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<p>First of all if you want to do it yourself using an Arduino then I would recommend using the Arduino Nano to save on weight. </p>
<p>If you don't want to rely on noises (as used by some battery monitors) then you could program the Arduino to trigger something off, maybe a visible LED or some other physical thing on... | 1163 | 2013-04-04T18:45:28.617 | |battery| | <p>I'm building a quadcopter and I've seen that a Li-Po battery must not be entirely discharged, otherwise it could damage it.</p>
<p>How do you know when you have to stop your quadcopter or robot in order to prevent damages, since the voltage doesn't drop? Which part should control the battery charge? ESCs? BEC? Flig... | How to know when a Li-Po battery is discharged? |
<p>I will try to answer 2 and 3.</p>
<h1>2</h1>
<p>I am pretty sure the cheap ones won't and I doubt expensive ones would.</p>
<p>In addition, The viscosity isn't the only thing you have to take into account when it comes to accuracy. Distance, height, wear of the tubes, wear of the motor, liquids that can potentially ... | 1167 | 2013-04-05T04:02:25.527 | |arduino| | <p>I'm building an arduino controlled pump system to be able to move fluids around. I need this to be fairly accurate, but extreme precision isn't required. Since there will be a variety of liquids moved through the pump, I've determined a peristaltic pump the best fit. But I don't think I fully understand them, and ha... | Can the rate of peristaltic pump's flow be accurate across changes in fluid viscosity? |
<p>Just a short note-
There is a significant difference between information filters and Klaman filters.
Although they are mathematically similar (inverses of each other), marginalization is simple in Kalman filters and complicated in information filters. However, smoothing is simpler in information filters while it is ... | 1180 | 2013-04-08T23:18:35.460 | |kalman-filter|algorithm|sensor-fusion| | <p>I read many sources about kalman filter, yet no about the other approach to filtering, where canonical parametrization instead of moments parametrization is used. </p>
<p>What is the difference?</p>
<hr>
<p>Other questions:</p>
<ol>
<li><p>Using IF I can forget KF,but have to remember that prediction is more com... | information filter instead of kalman filter approach |
<p>This is called "data association" in tracking literature. When you measure the position of an object, you need to know which object it was you measured. If you can estimate this probability, then you are free to choose the most likely association. This is a heavily researched topic, but boils down to Bayesian analys... | 1181 | 2013-04-08T23:25:40.900 | |kalman-filter|algorithm|sensor-fusion| | <p>I want to fuse objects coming from several sensors, with different (sometimes overlapping!) fields of view. Having object lists, how can I determine whether some objects observed by different sensors are in fact the same object? Only then I can truly write an algorithm to predict future state of such an object. </p>... | object level sensor fusion for multiobject tracking |
<p>Reading through some of the articles linked to in the Wikipedia article, I'll respectfully disagree with <a href="https://robotics.stackexchange.com/a/1183/37">@Theran</a>. The distinction seems quite well grounded, although Wikipedia does a poor job of making it. </p>
<p>The term <em>embedded systems</em> (ES) has... | 1182 | 2013-04-09T12:52:45.160 | |distributed-systems|embedded-systems| | <p>These days, one often hears of <a href="http://en.wikipedia.org/wiki/Cyber-physical_system" rel="noreferrer">cyber-physical systems</a>. Reading on the subject, though, it is very unclear how those systems differ from distributed and/or embedded systems. Examples from Wikipedia itself only make them look more like t... | Shedding light on "cyber-physical systems" |
<p>With a \$100-200 budget it's unlikely you can duplicate the functionality of a \$695 commercially-produced product. Your device may be slower, bulkier, noisier, less reliable.</p>
<p>One possible approach is to use dot matrix printer print-heads to drive pins. See example of pins being driven in a <a href="http:/... | 1198 | 2013-04-17T17:06:16.400 | |design| | <p>I'm a newbie in robotics, and I'm doing a project on dynamic Braille interface. Basically it's a 8*8 array of pins, which can be either totally up or down. How to use least motor as possible?</p>
<p>I'm thinking of using Arduino for easy interface with computer.</p>
| Dynamic braille interface |
<p>If I understood correctly, you are referring to <code>robotic tendons</code>.</p>
<p><img src="https://i.stack.imgur.com/RyYGi.jpg" alt="enter image description here"></p>
<p>There is a lot of material on the subject if you search google.</p>
| 1200 | 2013-04-18T08:17:48.590 | |microcontroller|robotic-arm|movement| | <p>I am looking for a specific name of the wire used for the robotic arm movement control and where can I find some of this online. I want to control it using the micro controller so please suggest some good development kit.</p>
| What is the wire used for hand movement of robot called ? where can I find it online ? |
<p>Non of the commercial air bearings I've seen have attempted to <em>seal</em> like this, so I think that your problems with vibration may lie elsewhere.</p>
<hr>
<p>The problems I have seen with air-bearing systems have been related to mechanical <a href="http://forums.reprap.org/read.php?14,131155,131155" rel="nof... | 1202 | 2013-04-18T10:21:39.047 | |linear-bearing| | <p>We have an air bearing for a planar xy motion. Today it consists of four pockets according to picture.</p>
<p><img src="https://i.stack.imgur.com/dET39.png" alt="Current design" /></p>
<p>In the current design there are no sealings around the peripheries of the pockets and we suspect that is the reason we get vibrat... | Problem with vibrations in air bearing |
<p>IR sensor are best used for detecting any thing but they are quite sensitive to IR lights and sunlight.So if in condition when you are not bothering about Ir rays and sunlight , you can always use a pair of IR LED and Photodiode to make a pair of IR sensor.</p>
| 1211 | 2013-04-21T13:33:17.253 | |motor|sensors| | <p>I have a small device that's picking up small rocks from a pile and moving them to another place. Its a kind of crude way of trying to push the whole pile onto a bigger gear and hoping one of them is pushed to one of the spaces between gears and taken around and falls off on the other side of the spinning gear. Here... | What kind of sensor do I need for knowing that something is placed at a position? |
<p>I don't think there would be parts not yet existent in robotics. The elevator itself is pretty much a cabin moving on a rail. It may not be built from off-the-shelf components, but building it shouldn't be difficult.</p>
<p>There are other reasons however, some of which are mentioned in the same Wikipedia article y... | 1214 | 2013-04-22T12:04:46.710 | |mobile-robot|research| | <p>In order to build and operate a <a href="http://en.wikipedia.org/wiki/Space_elevator">space elevator</a> moving crafts and people into space, there are two big challenges that have not been solved yet:</p>
<ul>
<li>Finding a cable with enough <a href="http://simple.wikipedia.org/wiki/Tensile_strength">tensile stren... | Space elevator: What is still needed, apart from the cable and propulsion? |
<p>One way to do this is complicated, involving computer vision and a robot arm or other manipulator that can directly affect the orientation of each rock.</p>
<p>The low-tech way to do it would be to use a separate conveyor that gave you one rock at a time, and use walls to funnel it into a gate that matches the inte... | 1218 | 2013-04-23T14:54:11.400 | |arduino|motor|microcontroller|motion| | <p>This is part two of my larger robot, it follows up what happens with the small rocks here: <a href="https://robotics.stackexchange.com/questions/1211/what-kind-of-sensor-do-i-need-for-knowing-that-something-is-placed-at-a-position">What kind of sensor do i need for knowing that something is placed at a position?</a>... | How do I adjust objects on a conveyor belt into the proper orientation? |
<p>The solution is actually not quite linear. There are at least two cases:
1) The fastest solution does not require maximum turning at all times.
2) The fastest solution does require maximum turning at all times.</p>
<p>For an example of 1), consider the goal is straight ahead of the drone.
For an example of 2), cons... | 1219 | 2013-04-23T15:56:36.040 | |design|algorithm|kinematics|navigation| | <p>Imagine a "drone" and a target point on a 2d plane. Assuming the target is stationary, there are eight parameters:</p>
<pre><code>P = my position
Q = target's position
V = my velocity
I = my moment of inertia
w = my angular velocity
s = my angular position
T = max thrust
U = max torque
</code></pre>
<p>The drone's... | Drone targeting |
<p>I updated ArduIMU's firmware and successfully got 100hz of output without disabling normalization.</p>
<hr>
<p><strong>Update:</strong> </p>
<p>Thanks to Kalman filter firmware of ArduIMU I got up to 180hz of output plus removing all noises.</p>
| 1221 | 2013-04-24T11:22:53.977 | |arduino|quadcopter|imu|pid| | <p>We are using <a href="http://code.google.com/p/ardu-imu/" rel="nofollow noreferrer">ArduIMU (V3)</a> as our Quadrotor's inertial measurement unit. (we have a separate board to control all motors, not with ArduIMU itself). </p>
<p>As mentioned <a href="http://code.google.com/p/ardu-imu/wiki/Output#Output_Rate" rel="... | Quadrotor control using ArduIMU |
<p>There's more than one way to do it (<a href="http://en.wikipedia.org/wiki/There%27s_more_than_one_way_to_do_it">TMTOWTDI</a>).</p>
<p>There are a several ways to connect 8 analog inputs to an Arduino.</p>
<ul>
<li>Add an analog multiplexer, as georgebrindeiro suggested. Such as: <a href="http://shieldlist.org/appl... | 1227 | 2013-04-25T17:21:33.500 | |arduino|microcontroller|input| | <p>I'm in the planning stages for a project using the Arduino Uno to control 8 distance sensors, and have run into a little road block, the Uno only has six input pins. So I'm wondering, is there any way for this to work? If so, how?</p>
| Connecting More Than Six Analog Input Pins to arduino |
<p>I was looking for something similar, and I found <a href="http://www.alicesastroinfo.com/2012/07/mars-rover-rocker-bogie-differential/" rel="nofollow noreferrer">Mars Rover Rocker-Bogie Differential</a> to be really helpful.</p>
<p>With my level of understanding it took me a while. But the link my professor provide... | 1235 | 2013-04-25T22:40:55.590 | |wheeled-robot|rocker-bogie| | <p>How does rocker-bogie mechanism keep the body flat / keep the solar panel almost flat all the time? I know there is an differential system that connect both rocker bogie (left and right) together. But how does it actually work?</p>
<p><em><strong>Edited:</em></strong> Please provide relevant references.</p>
| How does rocker bogie keep the body almost flat? |
<p>I found a web site that uses wifi if that would help with the quadcopter. endurance-rc.com They have some neat applications. I've put in an inquiry through their email chain. </p>
| 1246 | 2013-04-29T04:41:07.797 | |quadcopter| | <p>So I have a quadrocopter, it does come with a remote but I intend to run certain modifications to the copter, like installing a camera, a mechanical manipulator, and other random modifications. The remote that comes with the copter isn't flexible enough to help with such functions and plus it lacks any more buttons.... | Using an Xbox controller to fly a Quadrocopter |
<p>These are just terms to describe the "layers" of control on the robot. The "joint level" means the position of each actuator (leg), and the "task level" means the current goal of the robot (like go forward, go east, go to location X, etc). </p>
<p>This paragraph is about sensing. There are (apparently) position ... | 1253 | 2013-04-30T11:34:27.403 | |mobile-robot|control|walking-robot|hexapod| | <p>While doing a literature review of mobile robots in general and mobile hexapods in particular I came across a control system defined as "Task level open loop" and "Joint level closed loop" system.</p>
<blockquote>
<p>The present prototype robot has no external sensors by
which its body state may be estimated. T... | What is the difference between Task-Level and Joint-Level Control Systems? |
<p>Flow-rate meters based on measuring Coriolis-force reactions are widely used in process control systems.
The measurement principles are mentioned or illustrated at numerous web sites, including youtube video e2NGvrkmP8Y, <a href="http://www.youtube.com/watch?feature=player_embedded&v=e2NGvrkmP8Y" rel="nofollow ... | 1259 | 2013-05-03T07:44:58.167 | |mechanism|manufacturing| | <p>I've been watching too much <a href="http://science.discovery.com/tv-shows/how-its-made" rel="nofollow">How It's Made</a>, and I've been wondering how they build devices that spray/inject/dispense a finite amount of liquid (to within some amount of error). I wanted to try this for a hobby project. I'm working on th... | How to measure and dispense a finite amount of powder or liquid |
<p>There is now an easy way of installing ROS on OSX using conda: <code>conda install ros-noetic-desktop -c robostack</code>. More info on <a href="https://medium.com/robostack/cross-platform-conda-packages-for-ros-fa1974fd1de3" rel="nofollow noreferrer">https://medium.com/robostack/cross-platform-conda-packages-for-ro... | 1263 | 2013-05-05T21:22:41.277 | |ros| | <p>The latest OSX documentation I found on the website is from 2011, and the latest build is from over a year ago. I'm a complete n00b to all things ROS and wanted to start playing with it. What is the easiest way?</p>
<p><strong>Edit:</strong> <a href="http://www.ros.org/wiki/groovy/Installation/OSX/Homebrew/Source" ... | What is the easiest way to install ROS on OSX Mountain Lion? |
<p>The optimal reward function depends on the learning objective, i.e. what is to be learned. For simple problems it may be possible to find a closed form representation for the optimal reward function. In fact for really simple problems I'm confident it is possible though I know of no formal methods for doing so (I su... | 1266 | 2013-05-07T13:25:22.977 | |machine-learning| | <p>Let's think of the following situations:</p>
<ul>
<li>You are teaching a robot to play ping pong</li>
<li>You are teaching a program to calculate square root</li>
<li>You are teaching math to a kid in school</li>
</ul>
<p>These situations (i.e. supervised learning), and many others have one thing (among others) in... | What reward function results in optimal learning? |
<p>Read <a href="http://learn.adafruit.com/ir-sensor" rel="nofollow">Ada Fruits Tutorial</a> along with many other sources of IR tutorials out there.</p>
<p>Then for an Arduino I would use (and have used) <a href="http://www.righto.com/2009/08/multi-protocol-infrared-remote-library.html" rel="nofollow">Ken's IRremote ... | 1274 | 2013-05-08T13:30:52.200 | |mobile-robot|arduino|raspberry-pi| | <p>I bought my kid a <a href="http://www.gigo.com.tw/english/_toy/detail.php?MID=100&SID=101&ID=974" rel="nofollow">robotics kit</a> with several motors and an infrared remote control (you can steer the robot using IR remote control).</p>
<p>Now I want to take it to the next level and control the robots from a... | How to connect an infrared remote control to PC or Arduino or Raspberry Pi? |
<p>You need to command your motors by torque, and not speed</p>
<p>then with n motors, you get n vectors, so you now get 1 vector you regulate according the speed, and you compute the torque for each three motors.</p>
<p>To control an AC motor by current you need an inverter capable of Field Oriented Control, and for... | 1276 | 2013-05-08T17:33:04.103 | |control|motor| | <p>I have a three wheeled vehicle in a tricycle configuration attached to a fixed frame. Each wheel is powered by an AC electric motor. The AC motors are fed by motor controllers that take a speed demand. The single main wheel (which is also steerable) has a lower gear ratio than the rear wheels so it has a theoretical... | How can a load be balanced between multiple AC electric drive motors? |
<p>I've wanted to do something similar, so hearing of your experiences would be great. </p>
<p>The best thing I think would be to get a colorimeter, and build a calibration table into your code. Since paint can vary by manufacturer or medium additive (possibly even output levels if the tubes clog some), you could have... | 1277 | 2013-05-08T18:52:41.650 | |robotic-arm| | <p>I am developing a robot which paints using an airbrush (3D painting). I intend to use several colors as a CMYK printer, but I do not know how to do the conversion of RGB colors in the computer to the dosage of colors in CMYK.</p>
| How can I convert RGB colors to CMYK for my airbrush robot? |
<p>I think you're mixing two meanings of the word "sensitive". </p>
<h2>Input Sensitivity</h2>
<p>If you have an IMU that gives very raw ("twitchy") readings, then you should be able to generate the output of a less input-sensitive IMU by simply computing a <a href="https://en.wikipedia.org/wiki/Moving_average" rel=... | 1286 | 2013-05-10T21:09:58.213 | |kalman-filter|quadcopter|imu|uav| | <p>I noticed that some IMU units are tuned to be sensitive to small changes, other to large changes and some that can be adjusted between different sensitivities. I am familiar with the use of a Kalman filter to normalize readings, but I was wondering if my UAV could benefit from a second IMU where the two are set at h... | Is there a benefit to using 2 IMU units on a UAV set at different sensitivities? |
<p>Okay, so most(if not all) transational drift robots or meltys use an acceleorometer to indicate the heading of the robot. What this acceleorometer does is calculates the rate of rotation based on G-forces around a given radius. The data that is accumulated from the accelerometer is then used to light up an LED once ... | 1294 | 2013-05-14T19:46:34.603 | |navigation|movement| | <p>Concerning robots which rotate at high speed by spinning the drive motors in opposite directions, while still being able to simultaneously move in a direction (translate):</p>
<p>As far as I know this originated with competitive fighting robots, where it is known as "melty brain" or "tornado drive," according to wi... | What are the mechanics of translational drift? |
<p>There is at least two modalities along which servos (continuous or otherwise) usually fail: gear problems and motor breakdown.</p>
<p>When the gear fails (broken tooth, hard point, etc.), the servo may get stuck, free moving or any combination. When the motor breaks (usually the brushes inside the DC motor are the ... | 1301 | 2013-05-17T19:08:13.547 | |arduino|microcontroller|otherservos|wheeled-robot| | <p>I just got a kit and im not sure if its me or not but it appears one of the continuous servos might be broken. What happened first when I plugged it into the microcontroller, it made a humming sound when I sent it commands. The second continuous servo didnt work at all</p>
<p>I played around with different ports on... | What are the signs that a servo might be broken? |
<p>Your calculation is correct in magnitude but incorrect in sign, because gear B rotates oppositely to A (when the axis of D is fixed and D is not locked).</p>
<p>If D is locked (ie, the gear is not free to rotate in its plane) then A and B are locked together and rotate identically. </p>
<p>If the body V to which ... | 1302 | 2013-05-18T04:01:29.997 | |wheeled-robot|rocker-bogie| | <p>Following, the <a href="https://robotics.stackexchange.com/questions/1235/how-does-rocker-bogie-keep-the-body-almost-flat">previous question</a>, I am trying to calculate how much one rocker would rotate when the other is being rotated. I attached my calculation here.</p>
<p>I am trying calculate the rotation of ge... | Rotation ratio between left rocker and right rocker in rocker-bogie system |
<p>The motors in ABB robots have integrated brakes that are <strong>engaged when not energized</strong>. They hold the position of the joint and prevent the arm from falling if power is lost. The flex pendant enable switch actually drives a relay in the controller that removes or applies all power to the motors. This i... | 1306 | 2013-05-19T04:25:44.473 | |industrial-robot|servomotor| | <p>I was jogging the ABB IRB1410 and I noticed that the servo motors are humming even when the joints are not moving. The motor cuts off only when the guard switch in the flex pendant is released.</p>
<p><strong>What kind of mechanism which require the drive motors to keep running even when the joints are not moving ?... | Why are the IRB 1410's servos running even when the joints are not moving? |
<p>I finally got the problem solved. The problem was that I had selected Arduino UNO. After checking out the datasheets for my board I found that it had the same specs as Arduino Duemilanove AtMega328. After selecting it I got the things right.
So the general solution is check out the data sheets if you are using any s... | 1320 | 2013-05-23T18:21:33.780 | |arduino| | <p>I bought a new Roboduino atmega 328 board. Basically Roboduino is a modded version of Arduino UNO made by robokits.co.in. The problem is </p>
<p><strong>On Windows Plaform:</strong>
When I tried to upload a simple Blink program that's listed in the examples of Arduino IDE 1.0.4, I got error that
<strong>avrdude: s... | Problem uploading to Roboduino AtMega328 |
<p>I cannot comment yet; this is a supplement to ronalchn's answer.</p>
<p>Using an opto-isolator between the logic output and the motor control input 100% isolates the two circuits from each other and makes [multiply-]split-supplies trivial.</p>
<p>DGND > Digital > Opto < Analog < AGND</p>
<p>Under extreme de... | 1324 | 2013-05-24T07:13:49.387 | |motor|power| | <p>How can I provide more power to a DC motor that is in series behind a receiver circuit hacked out of a cheap RC car without burning up the receiver board? The board runs off two AAs at about 3V. I'm replacing the stock motor with a slightly larger one (12V, taken from a printer) and remounting it on a chassis for a ... | Additional Power to DC Motor via Second Power Source |
<p>For the motor, a stall current of 1A means that at stall, supplying 6V will cause the motor to draw 1A. The no-load current of 250mA means that supplying 6V will cause the motor to draw 250mA.</p>
<p>The half-bridge IC you have given has no current overload protection. Its peak current of 1.2A is high enough, but t... | 1327 | 2013-05-24T13:34:10.740 | |mobile-robot|motor| | <p>I ran into confusion while reading about motors.</p>
<p>Consider a motor with these specs:</p>
<ul>
<li>Maximum motor voltage - 6VDC</li>
<li>No load current - 250mA max.</li>
<li>Stall current - around 1A</li>
</ul>
<p>I am considering using the Texas Instruments L293D, with these specs:</p>
<ul>
<li>Output Cur... | How do I interpret these specs for a motor and motor driver? |
<p>You have to be very careful with those packs as they don't usually have under-voltage protection for themselves. You're pack is likely fine but the charger isn't seeing the minimum voltage required to begin charging and so it won't.</p>
<p>I found myself in nearly the same situation not too long ago and managed to ... | 1329 | 2013-05-24T17:32:40.517 | |battery| | <p>I used a <a href="http://www.hobbyking.com/hobbyking/store/__8934__Turnigy_2200mAh_3S_25C_Lipo_Pack.html" rel="nofollow">Turnigy 2200mAh 3S 25C Lipo</a> battery pack with <a href="http://www.hobbyking.com/hobbyking/store/__7637__Turnigy_balancer_Charger_2S_3S.html" rel="nofollow">Turnigy balancer & Charger 2S-3S... | Battery pack discharged |
<ul>
<li>Consider integrating an Android smartphone with the Arduino board, as then you get cameras, gps, accelorometers and even voice command.</li>
<li>If you have 2 units and you want to build in a camera on one, why not have it automatically follow the other one. This should not be too hard if you put a marker / be... | 1334 | 2013-05-27T10:38:08.170 | |arduino|sensors|radio-control|automatic| | <p>I bought an RC car about a year ago. A few days later I integrated an arduino nano into the vehicle. The only thing the arduino does is to receive the RC signal and pass it on to the esc/servo. So, basically it just does a big amount of NOTHING :)</p>
<p>Right now the wiring looks like this:</p>
<blockquote>
<p>... | Arduino Controlled RC Car. What now? |
<p>You can fly anything you want in class G airspace. Generally speaking, if you're far from any airport or military training area, you are probably walking around in class G. To be sure, though, you should consult a <a href="http://aeronav.faa.gov/index.asp?xml=aeronav/applications/VFR/chartlist_sect" rel="nofollow">... | 1339 | 2013-05-29T00:41:05.047 | |quadcopter| | <p>Okay, this might sound like a stupid question but, is there some sort of a permission in the US I might require to fly a quadcopter or a UAV for that matter? I couldn't find much help anywhere else. </p>
| Permission to fly UAVs |
<p>CF is lighter but you definitively need to know your source, many of the inexpensive tubes are quite brittle. In any case I do not recommend drilling holes in the tube use clamps.
Aluminium is somewhat heavier and will transmit vibration (balance your motors and props) but is readily available cheaper and easier to ... | 1344 | 2013-05-29T17:47:11.450 | |design|quadcopter| | <p>So building a quadrocopter from scratch HAS a lot of decision making, and I need some input on the material choice. </p>
<p>I have short listed Aluminum and Carbon Fiber for the Arms and support of the Quadrocopter.
I am a little short on cash to experiment with both of them. </p>
<p>So considering that I have en... | Aluminum vs Carbon Fiber |
<p>Keep in mind that "heavier" is not quite the term you're looking for. You should be trimming your SeaPerch to be neutrally buoyant, so unless the new payload creates significantly more drag than your old one, your existing motors should work fine (just with decreased acceleration in response to the increased mass).... | 1346 | 2013-05-29T20:19:28.193 | |motor|underwater| | <p>I am looking to upgrade the motors for SeaPerch underwater ROVs so we can carry heavier payloads and more equipment. </p>
<p>My question is, should I look for motors which have a higher RPM and lower torque, or with lower RPM but higher torque to gain a substantial power increase? If the latter, what threshold of ... | Upgrading the motors on a SeaPerch ROV - more torque, or more RPMs? |
<p>First, you haven't provided enough information. Your equation is nonlinear, which means that the behavior of the system as described depends not just on the coefficients of the difference equation, but on the range of values that $y$ can take on. From the looks of things, the closer that $y$ is restricted to 0, th... | 1356 | 2013-05-31T16:38:17.993 | |pid| | <p>I'm trying to use a PID to stabilize a system described from the following difference equation:</p>
<p>$$y_{k+1} = a y_k \sqrt{(1-y_k)}~~~ + b y_{k-1} ~+ c u_k$$</p>
<p>Can I use <a href="http://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method" rel="noreferrer">Ziegler-Nichols's rules</a> to find PID parameter... | Can I use Ziegler-Nichols's rules to find PID parameters for a non linear system |
<p>This has to do with the torque, or moment, the rotors induce on the body of the quadcopter/multirotor. If all of the rotors were to spin the same direction they would all induce a torque in the same direction causing the craft to yaw. Of course this is undesirable for many reasons. By spinning half of the rotors the... | 1367 | 2013-06-02T05:11:59.240 | |quadcopter|multi-rotor| | <p>While looking up information for the right propellers for my quadcopter, I realized that they had different orientations i.e. Clockwise and Counterclockwise. On further research I found that all multi-rotors have different combinations of these orientations. So my question is WHY? How does it matter if the propeller... | Prop Orientation on a Multirotor |
<p>For a basic multicopter, in the absence of any other way to control yaw, orientation does matter. A quadrotor needs a balanced set of rotation directions so that it can easily control yaw direction, and at equilibrium, all propellers can rotate at the same speed. This is primarily because all rotors in a quadrotor a... | 1370 | 2013-06-02T20:34:24.683 | |multi-rotor| | <p>This question stems from previous <a href="https://robotics.stackexchange.com/questions/1367/prop-orientation-on-a-multirotor">question</a>, where I asked why does the prop orientation matter so much for a multirotor. But on further research<sup>†</sup> I found that these reasons need not apply to a tri copte... | Prop orientation for tricopters |
<p>The LEDs on the board indicate the status of the Ardupilot. See the <a href="http://code.google.com/p/arducopter/wiki/AC2_LEDs" rel="nofollow">LEDs on the boards</a> on the Arducopter wiki for more detail. Of interest to you are likely the A (red), B (yellow), and C (blue) LEDs. LED A is solid when the motors are ar... | 1378 | 2013-06-04T07:07:59.703 | |uav| | <p>Using ArduPilot software (fixed wing, ArduPlane), I know that after I boot up I need to keep the system sit still while the gyros initialise.</p>
<p>When I have ground station in the field it's easy to know when it's safe to launch because the telemetry message tells me. But I don't always fly with a ground station... | How to tell when an ArduPilot has finished initialising its gyros (without referencing telemetry)? |
<p>You can use an Ethernet-enabled microcontroller as someone mentioned above. The board can be used as the interface between the network and the mechanism that you will be using to push the button.</p>
<p>For the mechanism you can use a servo motor or a pneumatic that releases with less force(you can control this by ... | 1408 | 2013-06-07T13:41:23.617 | |arduino|actuator| | <p>So I want to program something that will simply push a button, but controllable over ethernet. I'm new to robotics so I don't know where to start. What's the best way to control an actuator over a network connection?</p>
| Pushing Buttons Remotely over Ethernet |
<p>Despite its price, the Raspberry Pi is a rather powerful platform that can run most Linux desktop applications but the most CPU/memory hungry. For example, Quake 3 has been shown to <a href="http://www.youtube.com/watch?v=e_mDuJuvZjI" rel="nofollow">run in 1080p</a> on it.</p>
| 1413 | 2013-06-09T21:29:14.680 | |mobile-robot|raspberry-pi|artificial-intelligence| | <p>In general, is a Raspberry Pi processor powerful enough for a mobile chatbot? I want to make a small mobile robot that is like a chatbot. Is a Raspberry Pi processor powerful enough for any type of AI robotics?
As far as a mobile robot, I want to make a wheeled robot about one foot in every dimension. The chatbot ab... | Is a Raspberry Pi processor powerful enough for a mobile chatbot? |
<p>It sounds like you have 6 legs with some number of PID-controlled joints on each leg. You would like to move 3 legs at a time, while the other 3 legs stand in a stable tripod configuration.</p>
<p><strong>Instead of figuring out how to move each set of 3 legs as one unit, you should be treating them as individual ... | 1414 | 2013-06-10T16:08:43.623 | |mobile-robot|pid|legged|walking-robot|hexapod| | <p>I am currently working on a legged hexapod which moves around using a tripod gait. I have two sets of code to control the tripod. </p>
<p>Set 1: Time based control</p>
<p>In this code set, I set the tripod motor set to move at their rated rpm for a required amount of time before shifting to the other tripod motor ... | PID Conundrums for Legged Robots |
<p>In short, yes, there are a number of robotics companies catering to just your needs. Specifically which apply to you depends on what type of robot you desire. Naturally cost varies with the complexity and durability. For example if you would be satisfied with a differential drive robot for indoor use then the <a hre... | 1416 | 2013-06-11T00:11:39.623 | |mobile-robot|battery|reinforcement-learning| | <p>I'm involved in research on psychologically plausible models of reinforcement learning, and as such I thought it'd be nice to try and see how well some to the models out there perform in the real world (i.e. sensory-motor learning on a mobile robot). This is already been done in some robotics labs, such Sutton's <a ... | Building robots with high reliability, durability, and battery life |
<p>It may be worthwhile to consider how laser scanners work. We know that it is possible to send a beam of light at an object, and detect how long it takes to be reflected back to the sensor to measure its distance.</p>
<p>First of all, we use lasers because reflection of the light from the object is so important. las... | 1435 | 2013-06-14T22:04:40.517 | |localization| | <p>I'm looking at laser scanners and I see a huge range of detection distances. The furthest I've see are 30m if you exclude the very expensive ones that claim up to 150m. My question is what is the reason for the huge difference in range/price. I would think that with a laser it wouldn't be that difficult to detect... | laser scanner distance |
<p>If adjacent motors are 1 unit apart, the overall path-length of an X form is 2√2, or about 2.8284, and the overall path-length of a Steiner form is 1+√3, or about 2.732, which is 3.5% less. It is likely that hub mounting will decrease either or both of the total lengths by a few percent, but I will ignore that fact... | 1437 | 2013-06-15T22:30:49.067 | |design|quadcopter| | <p>I haven't made or flown any quadcopter, but I am fascinated by them.
But when looking at the frame of a lot of designs, after whachting <a href="http://www.youtube.com/watch?v=dAyDi1aa40E" rel="nofollow">this video</a> I wondered why a lot the frames are in an X shape. Since the most efficient shape would according ... | Most material efficient quadcopter frame |
<p>"<a href="http://en.wikipedia.org/wiki/Least_significant_bit" rel="nofollow noreferrer">LSB</a> <a href="https://en.wikipedia.org/wiki/Root_mean_square" rel="nofollow noreferrer">RMS</a>" means the root-mean-squared value of the total noise in least significant bits of the digital channel. Roughly, that's... | 1449 | 2013-06-20T07:12:43.997 | |imu|accelerometer|gyroscope|noise|magnetometer| | <p>I'm trying to understand how noise is represented for accelerometers, gyroscopes, and magnetometers so that I can match the requirements of my project with the standard specs of these sensors. </p>
<p>I want the output of a 3 axis inertial sensor to be values in meters/sec/sec, gauss, and radians/sec for each axis,... | How are units of noise measurement related to units of a sensor's data measurement? |
<p>The whole point of the chipselect pin is so that multiple devices (in this case, shields) can share the same SPI bus.</p>
<p>As long as no two chipselect pins are the same, you ought to be fine. Make sure only one chip select pin is on at any given time.</p>
| 1454 | 2013-06-22T00:59:26.140 | |arduino| | <p>I was wondering if it is possible to plug a motor shield on top of an Ethernet shield, even though the direction pins on the motor shield would be connected to the same pins as the spi bus. I was thinking that it would work if, in the coding, I disabled both chip selects on the Ethernet shield before I used the mot... | Motor and Ethernet shields together |
<p>Is an underwater quadrotor possible? Absolutely. Whether it's practical in that configuration is a different matter. </p>
<p>In air, viscosity and buoyancy are negligible; in water, they are not. An aerial quadrotor will expend energy fighting gravity, while an underwater quadrotor can simply rely on positively... | 1466 | 2013-06-24T05:26:18.397 | |quadcopter| | <p>Just out of curiosity, can the concept of a Quadcopter be applied to an ROV? Would it work the same way underwater as it would be in Air? If not what kind of modifications it would take to implement that idea, underwater?</p>
| Quadcopter application underwater |
<p>In case you're not already aware, the problem you are asking about is generally referred to as the <a href="https://en.wikipedia.org/wiki/Boundary_value_problem" rel="nofollow">two-point boundary value problem</a>. For some systems, a closed form solution may be extremely difficult to calculate and may not even exis... | 1483 | 2013-06-26T22:51:52.753 | |control|motion-planning| | <p>I'm trying to find the optimal-time trajectory for an object (point mass) from point <code>p0</code> with initial velocity <code>v0</code> to point <code>p1</code> with velocity <code>v1</code>. I'm considering a simple environment without any obstacles to move around. The only constraint is a maximum acceleration i... | Optimal-time trajectory in 2D and 3D with simple constraints |
<p>Moving it around requires, apart the mechanics, always a free and therefore unused space. Wouldn't you rather like to know, <em>what</em> is in <em>which</em> position? And for the barcode: it can become unreadable by ice. I'm thinking of using RFID for a similar project for about 10 fridges with each 30 boxes in it... | 1489 | 2013-06-27T10:05:35.743 | |arduino|motor|sensors|cameras| | <p>I'm endeavoring to prototype a challenging sorting mechanism inside a fridge and would appreciate any constructive tips on how to get from the specs to a plausible design.</p>
<h3>Problem</h3>
<p>The aim of the game is to identify and sort food items in the limited space of a fridge
- such that a user would push... | automatic sorting with barcode identification inside a refrigerator |
<p>Lithium thionyl chloride / SOCl2 batteries have excellent <a href="http://www.allaboutbatteries.com/Battery-Energy.html" rel="nofollow noreferrer">energy density</a> but are not aimed at high-current applications and are not rechargeable, so it seems likely that you can save weight and cost by using some other kind ... | 1500 | 2013-06-29T00:30:43.873 | |power| | <p>I am building a robot where power density is critical, and looking into using lithium thionyl chloride (SOCl2) batteries. I will be drawing around 20A constantly and need between 12 and 17V. The batteries I have found so far are AA-sized and designed to deliver 100mA, 3.6v, 2.4Ah, and weigh 19g each. I could picture... | lithium thionyl chloride batteries to generate 20A @ 14.4V |
<p>This is an extremely general question. What code you will use will depend on the type of "robotic movement" you are attempting to achieve, and what platform you are running the code on.</p>
<p>Let's say you want to control a stepper motor from python running on a Raspberry Pi. Stephen Phillips has written <a href="... | 1503 | 2013-06-29T22:41:17.110 | |python| | <p>Are there any Python3 modules used to program robotic movement by declaring a device or component and then providing the instructions? I am not looking for modules that test the components.</p>
| Python3 Modules for motor movement |
<p>You need to use a PID algorithm to control the speed of the motors, that way you'll be able to make them spin as slow as you need while still getting torque. The PID algorithm needs to measure the speed of your motor somehow, the typical way is to place some optical encoders in the wheels, this is a must for any rov... | 1514 | 2013-06-30T18:23:12.643 | |motor|pwm| | <p>So I built three little bots so far. </p>
<p>One with a raspberry-pi, (6V motors), one with an arduino (12V motors), and another with an arduino but a hacked remote car (7ish, volt motors):<br>
<a href="https://i.stack.imgur.com/AJ45l.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/AJ45ls.jpg" alt="enter ... | Reducing motor speed without jamming up |
<p>The snow problem you're referring to seems to that the car can no longer tell where the edge of the road is.</p>
<p>Even in heavy traffic, a good driver still maintains enough space from the car in front that plenty of road is visible, and the side of the road identifiable from LiDAR. This is not common practice, b... | 1518 | 2013-07-01T16:27:51.393 | |ugv|lidar| | <p>If a street is extremely crowded to an extent that the terrain is not visible from the point of view of the LIDAR (e.g. in google's self driving car), can it still manage to localize itself and continue to operate? I recall Sebastian Thrun saying that Google's car cannot navigate through snow filled roads since the ... | How do visual obstructions impact the ability to localize using LIDAR? |
<p>You may want to check out <a href="https://robotics.stackexchange.com/questions/167/what-are-good-strategies-for-tuning-pid-loops">this question on how to tune PIDs</a>. </p>
<p>It sounds like you're confusing the role of <code>error</code> in this calculation. The PID equation takes the error measurement (actual... | 1524 | 2013-07-02T12:06:21.443 | |arduino|pid|line-following| | <p>I'm working on building a line follower robot and want to optimize its performance. It was suggested that I use a PID algorithm. I read a lot about PID but am confused a bit regarding following:</p>
<p>I've calculated the error_value using $k_p * proportional + ...$
But regarding the change in the motor speed I'm c... | Line Follower optimization |
<p><sub>This should have probably been a comment to @RobertEnglish answer ... but comments don't seem to allow pictures</sub></p>
<p>Bavel gears. Plastic ones should be rather inexpensive.</p>
<p><a href="https://i.stack.imgur.com/RzlZL.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/RzlZL.png" alt="... | 1538 | 2013-07-05T03:47:23.300 | |motor|motion|movement|driver|linear-bearing| | <p>I am interested in using this miniature motor <a href="http://www.newscaletech.com/technology/squiggle-motors.php" rel="nofollow noreferrer">Squiggle Micro Motor</a> to create very tiny <strong>horizontal</strong> movements. However, due to very limited space, I can only place it <strong>vertically</strong> within m... | How to convert vertical motion to horizontal? |
<pre><code> A great way to learn C/C++ for arduino is by going to the website: ardx.org/CIRC01
</code></pre>
<p>This website is completely and gives great mini projects that involve electronics and then gives an example code and a great explanation of how the code works. This site consists of 11 projects and explains ... | 1544 | 2013-07-06T13:25:20.640 | |arduino| | <p>I have no problem in reading circuit schemes, connecting wires, resistors etc. (basing on for example instructables.com), but I've only tried to learn Java (a while ago) and it's difficult to me to find out what's going on with all this C-code-stuff.
Are there any tutorials that are focused on the programming part?
... | Arduino C/C++ progamming tutorials |
<p>If you want to maximise efficiency, you go with two rotors: a main rotor, and a tail rotor. I.e. a traditional helicopter. With the common CCPM setup (Cyclic Collective Pitch Mixing), you have three servos controlling the main rotor. Together they can tilt it any direction and control the pitch on the blades. As you... | 1552 | 2013-07-08T00:46:21.340 | |quadcopter|multi-rotor| | <p>Hy, I just found useful to post my idea here. </p>
<p>I've seen videos about automated quadcopters: <a href="http://www.ted.com/talks/raffaello_d_andrea_the_astounding_athletic_power_of_quadcopters.html" rel="nofollow">http://www.ted.com/talks/raffaello_d_andrea_the_astounding_athletic_power_of_quadcopters.html</a>... | Use of automated tricopters instead of quadcopters? |
<p>If you want sub-meter tracking of the moving object, GPS alone will not be sufficient. I concur that passive vision-based techniques will require a huge amount of engineering to implement, not to mention substantial size, weight, and power. I recommend using differential GPS techniques -- not exactly easy, but sim... | 1554 | 2013-07-08T06:46:38.617 | |arduino|quadcopter|gps| | <p>If this has already been answered, by all means please point me to it.</p>
<p>I am in the process of building a quadcopter which I eventually plan to run autonomously by allowing it to track an object and take a video feed of it moving.</p>
<p>GPS is one of the options I've considered, basically:</p>
<ul>
<li>GPS... | Track a moving object |
<p>Here's an intuitive way to think about this. A quadrotor has 4 motor speeds that you can adjust to control 4 things: vertical lift, pitch angle, roll angle, heading angle. </p>
<p>A trirotor has 3 motor speeds and therefore only let's you control 3 things, one of the four previously listed has to go. Using @srim... | 1562 | 2013-07-09T11:15:30.823 | |design|quadcopter|uav| | <p><a href="https://robotics.stackexchange.com/a/549/37">An answer</a> to the question <a href="https://robotics.stackexchange.com/q/543/37">Why are quadcopters more common in robotics than other configurations?</a> said:</p>
<blockquote>
<p>You need 4 degrees of freedom to control yaw, pitch, roll and thrust.</p>
<p>... | If you can create pure yaw motion with a quadcoptor then why won't this work with a tricoptor? |
<p>Ian's answer is mathematically correct. However, on most processors division takes longer than multiplication. So if you're at all pressed for processor resources you would want to precalculate a gain and offset for each channel, and apply it:</p>
<p>$k_{zz} = \frac{1}{S_{zz}}$</p>
<p>$b_{zz} = -\frac{B_z^{0g}}{... | 1570 | 2013-07-10T11:07:19.197 | |accelerometer|calibration|errors| | <p>I found <a href="http://www.kionix.com/sites/default/files/AN012%20Accelerometer%20Errors.pdf" rel="nofollow">a good explanation</a> on how to remove accelerometer bias (when on flat table only one axis should show values, the other two should be 0). I've calculated S and B factors (page 3):</p>
<blockquote>
<p>R... | Accelerometer bias removal |
<p>I did this exact same project 6 years back. I used two servos. The first was a continuous rotation servo with a spool the pull the spider up. The spool did not have an end on it so that when the spool turned parallel to the string it all came loose and the spider fell. It was simple and effective, although the CR se... | 1571 | 2013-07-10T14:31:23.340 | |motor|rcservo| | <p>For Halloween, I'd like to build a spider that drops from the ceiling when it detects motion and then rewinds itself back up to scare the next kids. I already have a lightweight foamish spider from Hobby Lobby that I'd like to use, but I need help adding the smarts to it to scare the kids.</p>
<p>Ideally, it'd be ab... | How to raise/drop a spider? |
<p>I realize this question is 2 years old, but I have direct recent experience with this. The way I did this is with 6 rotated cube positions with 1000 points at each position, so a total of 6000 samples.</p>
<p>I'm assuming Matlab/numpy nomenclature, where NxM means N rows and M columns.</p>
<p>I assume an equation... | 1579 | 2013-07-10T20:44:48.130 | |sensors|accelerometer|calibration|errors| | <p>I've already <a href="https://robotics.stackexchange.com/questions/1570/accelerometer-bias-removal">asked a related question (accelerometer bias removal)</a> here on robotics and got a bit better results on corrected accelerometer output. To get even better results I found the <a href="http://www.vectornav.com/suppo... | Accelerometer calibration - how to get cross-axis sensitivities |
<p>Or you could just do what I have done and scavenge two DC motors plus gearboxes from used cordless drillers. Mine are from 14.4v drillers and I am operating them using 3S LIPOs (11.1v). The LIPOs are not that expensive if you buy them rated at say 2200mAh (more current capacity = more cost). You don't even need a ve... | 1581 | 2013-07-11T15:19:47.430 | |motor|wheeled-robot|battery| | <p>I have a project which requires a robot to move around a room with a flat surface (concrete floor).</p>
<p>The robot must carry a laptop. I estimated that the total weight would be 6-7kg (including motors, battery, laptop, motor controller board and other mics items). I would like it to move at about the same speed... | Choosing motor and battery for a robot |
<p>I can say positively that 900Mhz china video transmitters can affect 2.4Ghz frequency range. I experienced this first hand and confirmed interference on my spectrum analyzer, it can cause harmonics on the 2.4Ghz but when the tx and rx are close it appears to have an affect on the noise floor too, using those low pas... | 1582 | 2013-07-11T18:31:18.143 | |multi-rotor| | <p>I'm starting to attempt to fly FPV on my quadrotor. I am using a FrSky D8R-II 2.4 GHz frequency hopping diversity receiver (two antennas) for control and recently added a <a href="http://www.readymaderc.com/store/index.php?main_page=product_info&cPath=11_30_31&products_id=348" rel="nofollow noreferrer">no-na... | Interference between 900 MHz video transmitter and 2.4 GHz control radio |
<p>Is it possible to use multiple ultrasonic sensors on a single robot? Yes: <a href="http://www.societyofrobots.com/sensors_sonar.shtml" rel="nofollow noreferrer">"Using Multiple Sonar Sensors"</a>.</p>
<p>As you have already figured out, one sensor often receives echoes of pings sent by another sensor.
There are sev... | 1584 | 2013-07-11T22:16:02.167 | |sonar|sensor-error| | <p>Our robot has a circular array of 12 sonar sensors that looks like this:</p>
<p><img src="https://i.stack.imgur.com/Q5dBX.jpg" alt="enter image description here"></p>
<p>The <a href="http://www.hobbyking.com/hobbyking/store/__31136__ultrasonic_module_hc_sr04_arduino.html" rel="noreferrer">sonar sensors themselves<... | How to deal with sonar crosstalk |
<p>Your intuition is correct. We can look at the difference in arc length that each wheel will roll for a given <a href="http://en.wikipedia.org/wiki/Circular_sector" rel="nofollow">sector</a> (specified by $\theta$ in degrees).</p>
<p>$$d_l = \frac{\theta*2\pi{r}}{360}$$
$$d_r = \frac{\theta*2\pi(r+A)}{360}$$</p>
<... | 1602 | 2013-07-16T11:26:28.637 | |kinematics| | <p>I want to give my robot a differential mechanism for the system of turning and steering. Considering the case of turning a right-angled corner, the robot will achieve this by following a gradual circular arc through the intersection while maintaining a steady speed. To accomplish this end, we increase the speed of t... | How to design a differential steering mechanism? |
<p>I have worked with quite a few servos (Industrial and RC) and from my experience they don't come with a limit switch that actually takes the current off the motor when they hit a limit. They are however limited in rotation by the PWM signal you send them and are as such limited to a rotation safe area. </p>
<p>It d... | 1607 | 2013-07-16T17:57:51.097 | |rcservo| | <p>I'm moving from controlling a robot arm with basic time based motors controlled using a raspberry pi and python to a more advanced robotic arm that has servos (e.g <a href="http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/Hitec-HS-425BB-Servo-Specsheet.pdf" rel="nofollow">HS-425BB</a>). With the time based mo... | Do servos stop at their limits automatically? |
<p>We build a new version and its now available for download:</p>
<p><a href="http://code.google.com/p/ardu-imu/downloads/detail?name=arduimu_vD" rel="nofollow">http://code.google.com/p/ardu-imu/downloads/detail?name=arduimu_vD</a>....</p>
<p>The problem completely gone in this version. Read comments in arduimu_vd.in... | 1614 | 2013-07-17T16:50:15.297 | |arduino|quadcopter|noise|ardupilot| | <p>We are using <a href="http://code.google.com/p/ardu-imu/" rel="nofollow noreferrer">ArduIMU (V3)</a> as our Quadrotor's inertial measurement unit. (we have a separate board to control all motors, not with ArduIMU itself). </p>
<p>Now we have a problem with ArduIMU's sensors output. When we put our quadrotor steady ... | ArduIMU noisy output in Quadrotor |
<p>If the getting started guide claims you can run it of a computers USB port, it will work at about .5 amps. A normal computer power supply limits the current to a USB port to .5 amps. Doing some research on the Beaglebone Black's site <a href="http://beagleboard.org/Support/FAQ" rel="nofollow">http://beagleboard.org/... | 1618 | 2013-07-18T02:34:04.530 | |microcontroller| | <p>What is the minimum amount of power that a beaglebone needs to start up? This would be with no peripherals attached besides host usb. The getting started guide claims that it can run off of a computer's usb power, but makes no mention of how many amps are actually needed. I saw a mention of older kernels limiting ... | Beaglebone Black power draw |
<p>I'll chime in.</p>
<ol>
<li><p>You could use piezoelectric inchworm motors. The approach is outlined here: <a href="https://www.techbriefs.com/component/content/article/tb/techbriefs/mechanics-and-machinery/2273" rel="nofollow noreferrer">https://www.techbriefs.com/component/content/article/tb/techbriefs/mechanics... | 1622 | 2013-07-18T02:20:07.367 | |design|mechanism| | <p>How would you motorize the joints in an Iron Man suit? You need something fairly shallow, I would think, probably dual servos sitting on either side of an elbow or knee joint or either side of your hips, but how do you get motorized action there without dramatically adding to the thickness of the joint? </p>
<p>Bic... | How do I motorize the elbow socket and other joints in a powered exo-skeleton? |
<p>For the smallest (and cheapest) of multicopters, DC brushed motors are well in use: <a href="http://www.rcgroups.com/forums/showthread.php?t=2009496" rel="noreferrer">http://www.rcgroups.com/forums/showthread.php?t=2009496</a>
They are coreless motors<sup><strong>1</strong></sup> and have very little inertia, can ac... | 1627 | 2013-07-18T21:37:55.480 | |quadcopter|brushless-motor| | <p>I've been thinking about starting a quadcopter project, maybe building it from scratch. One of the main barriers-to-entry for me is the motors: it seems like most quadcopters use brushless motors. I have some experience with DC motors and using PWM signals to regulate speed, but no experience with brushless motors. ... | Why do quadcopters use brushless motors? |
<p>To control the motor with logic gates, you could make a circuit with a monostable multivibrator (or “one-shot”), an R-S flipflop (or R-S latch), and an AND gate or an OR gate to combine the one-shot and latch outputs. You would use an AND if you want the motor to run when both the latch and the one-shot are active... | 1630 | 2013-07-19T19:14:17.173 | |motor|raspberry-pi| | <p>I have some crude time based motors taken from a robot arm that we upgraded to proper servos. I want to be able to power a conveyor belt with one of them and I was wondering how I would go about the following setup:</p>
<p>A ball drops through a hole onto the conveyer belt hitting a lever switch on its way through.... | Controlling a conveyor belt with a time based motor |
<p>It turns out VirtualBox was causing everything to not work properly for some reason. Now I'm using VMware and everything's running fine. What confused me was that I was getting errors that I found online and that even after trying every fix I could find some would still be there. Next step is getting XYZ coordinates... | 1633 | 2013-07-19T22:01:54.720 | |ros|kinect| | <p>Whenever I try using <code>openni_launch</code>, it works normally, however, when I try viewing an image using the kinect's rgb or depth camera, or even recording a simple <code>bagfile</code> with data from the kinect, I am unable to see any picture and <code>rosbag</code> does not record any data, and after a few ... | How can I get data from my kinect? |
<p>Two days? Eeek!</p>
<p>I wouldn't try to simulate the thing at a circuit level. If you're an EE and you're familiar with circuit simulation packages then using SPICE (or whatever) to simulate the <em>system</em> may let you slide by with an acceptable performance.</p>
<p>Personally, if I were designing one of th... | 1637 | 2013-07-21T17:33:49.660 | |mobile-robot| | <p>I am a graduate student trying to make my own Line follower Robot for my minor assessment, I've all <strong>hardware</strong> parts and all <strong>data-sheets</strong> with me, I've attended a workshops of Robotics and studied a lot on <strong>Line follower robot</strong>. I have a good knowledge of C Programming a... | Paper work before I do make my own Line follower Robot |
<p>I'm pretty sure that people at the place that manufactured your stepper motors did, in fact, write up a datasheet including operating torque specifications and lots of other information.</p>
<p>It is unfortunate that all too often a person ends up with some electrical part in his hand, and somehow the datasheet was... | 1638 | 2013-07-21T18:33:28.620 | |stepper-motor|cnc| | <p>I have been looking online for a while, and I cannot seem to find any steppers without any torque ratings. (<strong>Operating torque, not holding torque.</strong>) I even looked on hobby sites that usually have all the ratings, including Adafruit and Sparkfun. I only have found one ever that said the operating torqu... | WHY are there no operating torque specifications on steppers? |
<p>To answer your first question: if you really want to find the true kinematic equations for differential drive, I wouldn't start approximating by assuming that each wheel has moved in a straight line. Instead, find the turning radius, calculate the center point of the arc, and then calculate the robot's next point. T... | 1653 | 2013-07-25T07:54:49.897 | |mobile-robot|kinematics|motion|two-wheeled|forward-kinematics| | <p><strong>How do you calculate or update the position of a differential drive robot with incremental sensors?</strong></p>
<p>There is one incremental sensor attatched to each of the two differential wheels. Both sensors determine the distance $\Delta left$ resp. $\Delta right$ their wheel has rolled during a known t... | Calculate position of differential drive robot |
<p>A machine is just a device which is defined to do a particular task whereas a robot can execute any task given to it through programming</p>
| 1654 | 2013-07-25T16:30:23.483 | |industrial-robot| | <p>What is the difference between a Robot and a Machine? At what point does a machine begin to be called a robot?</p>
<p>Is it at a certain level of complexity? Is it when it has software etc?.</p>
<p>For instance: A desktop printer has mechanics, electronics and firmware but it is not considered a robot (or is it). ... | What is the difference between a Robot and a Machine? |
<p>If you are concerned about the milk coming in contact with the air. I'd suggest using a plastic bag which the air from the first solenoid pours into. On expansion, the plastic bag(filled with air) will force the milk in the container to push out through the second solenoid. This way doesn't come in contact with milk... | 1660 | 2013-07-26T18:41:28.633 | |arduino| | <p>I am working on a homemade vending machine project that serves milk and cookies, using arduino and some basic servos and stuff.</p>
<p>The problem is: I really have no clue on how to protect the milk to last long, or how to even know if the milk is still ok to drink.. All I really know is that air is bad for the mi... | How to protect the milk in a homemade vending machine? |
<p>Sugru is great for this kind of thing, but it can be a little pricey. An alternative is <a href="http://www.instructables.com/id/How-To-Make-Your-Own-Sugru-Substitute/" rel="nofollow">Oogoo</a>, a DIY mixture of silicone caulk, cornstarch, and (optional) pigment.</p>
| 1670 | 2013-07-28T15:19:02.270 | |cnc| | <p>I’m trying to inject some kind of rubber around an aluminum strut to form “feet” for a robot. I’ve already milled the mold, but I’m having trouble finding an inexpensive and readily available rubber compound that will cure without exposure to air. Ideally it should cure to about the consistency of a silicone O-ring.... | Moldable rubber for "feet" |
<p>I think the question refers to this sort of device: <a href="http://en.wikipedia.org/wiki/Servo_%28radio_control%29" rel="nofollow">RC servo</a></p>
<p>Those usually aren't very high performance so they're not going to be able to track a generated motion profile very well. Most commercial motor control systems use... | 1678 | 2013-07-31T00:04:17.147 | |otherservos|kinematics| | <p>I made a small crawler robot a little while ago that had two legs with two degrees of freedom each, so 4 RC servos total. While I was programming the movement of the legs I noticed that they moved rather stiffly. It makes sense that the RC servo's internal controller would have a very quick response to position comm... | Smooth servo movement for a crawling robot |
<p>If I understand your question, you are asking whether a vehicle balancing on two wheels (or two wheels and one <a href="http://en.wikipedia.org/wiki/Caster" rel="nofollow">caster</a>) will be able to move straight, or at least predictably, if both wheels were driven from the same motor and used a differential. </p>... | 1682 | 2013-07-31T17:41:12.177 | |motor|wheeled-robot|motion|wheel| | <p>I am in the concept phase of a driving robot. The two wheels on the front axle will be powered, while the rear will be dragged along. The rear is also responsible for steering but this has noting to do with my question.</p>
<p>Since the robot is required to make relatively sharp turns at high speed. Therefore I hav... | Does a vehicle with defferential gear still move straight? |
<p>There are a variety of GPS units available that use plastic cases to protect against the elements, and they are all plastic. </p>
<p>For example, <a href="https://www.google.com/search?q=garmin+puck&tbm=isch" rel="nofollow noreferrer">these Garmin units</a>.</p>
<p>It sounds like you're really asking about wh... | 1687 | 2013-08-01T02:26:37.093 | |gps|protection|coverage| | <p>I'm going to be embarking on an autonomous robot project and I was going to be using GPS to navigate to waypoints (I'm aware of the margin of error when it comes to localization with GPD but I live in a lovely area with many open fields). </p>
<p>I was going to use Adafruit's Ultimate GPS Breakout board with my Ras... | Can GPS modules work inside plastic enclosures? |
<p>I'm not familiar with that platform. But in general, no, you do not need separate batteries for each motor.</p>
<p>Also in general, if you need 2-7.5V for each motor, then you probably want one honkin' big battery that puts out 7.5V or slightly more. You could use a 12V battery and take care with your drive comma... | 1693 | 2013-08-01T22:08:53.750 | |motor|battery| | <p>For the Dagu Wild Thumper 6 Wheeled platform, or any multiple motor system, do I really need 1 battery for each motor? Or should I just buy 2 for either side of the platform. In addition, for larger motors like the ones on this platform, how do I deal with the power generated from a coasting motor?</p>
<p>I want to... | Do 6 motors require 6 individually-assigned batteries? |
<p>According to the link you provided, you can use 5V or 3.3V directly on the sensor (it already have a voltage regulator). Since the arduino is able to send 3.3V or 5V you can use both of them directly without any level converter.
You can see on the video <a href="http://lukagabric.com/arduino-mpu6050/" rel="nofollow"... | 1697 | 2013-08-02T15:36:39.800 | |arduino|sensors|quadcopter|logic-control| | <p>I bought this MPU-6050: <a href="http://www.ebay.com/itm/MPU-6050-6DOF-3-Axis-Gyroscope-Accelerometer-Module-for-Arduino-DIY-/261231955458" rel="nofollow">link</a></p>
<p>According to the manufacture site, the sensor logic level is 3.3V (though the <em>ebay</em> page says <code>Power supply :3-5v</code>)</p>
<p>Sh... | MPU-6050 + Arduino nano - Logic converter or not? |
<p>I have a bot with 2 independently driven wheels. </p>
<p>I chose to use a gyro to keep it heading in the desired direction, bumps slippage and even picking it up and turning it around are of little consequence to it as it will just correct it's heading.</p>
<p>I use a single PID, which adds/subtracts a correction ... | 1711 | 2013-08-05T21:23:04.340 | |pid|differential-drive| | <p>Consider a differential drive robot that has two motorized wheels with an encoder attached to each for feedback. Supposed there is a function for each DC motor that takes a float from -1 to 1 and sets the PWM signals to provide a proportional amount of power to that motor. Unfortunately, not all motors are created e... | Approach to using PID to get a differential robot driving straight |
<p>There is no difference in between them. Motors are categorized by type (brushed or brushless), size, kv rating and the number of poles. The size and kv rating are usually what determine what application it can be used in.</p>
| 1712 | 2013-08-06T09:26:02.310 | |motor|brushless-motor| | <p>I am working on a robot with focus on speed. At the moment I am looking for a suitable motor but it would help if I understood the difference between the various options.</p>
<p>To provide some background, I have not worked with RC model components before, but I think this is the only place for me to find the compon... | What is the difference between RC motors for cars and helicopters? |
<p>I recommend arranging your sensors like the following:</p>
<pre><code> Thickness of Line
<--------> /\
| | / \
| * * | ||
| | || moving
* | | * || direction
... | 1728 | 2013-08-08T11:47:18.693 | |mobile-robot|sensors|automatic|line-following| | <p>I'm working on a robotics project, and I am using grayscale sensors to automatically follow a black line: turning 90 degrees, going round in a circle, and passing through gaps in the lines etc. I was wondering what is an effective way to detect the colours and move it through the lines, with five or six grayscale s... | What is an effective distribution of grayscale sensors on robot |
<h3>Text mode vs PDU mode</h3>
<p>The SIM900 module supports both text and PDU mode. Please note that some AT commands have different syntax depending on which mode is currently active. </p>
<p>To check which mode is currently active (0: PDU mode, 1: Text mode):</p>
<pre><code> AT+CMGF?
</code></pre>
<h3>Retrieving... | 1743 | 2013-08-14T08:20:38.523 | |arduino|microcontroller| | <p>I am using SIM900A for some purpose and want to know the number of the sender from where a message comes. I am unable to find the specific AT command related to receiving message which give me number from where latest message comes.</p>
<p>I had used AT+CNMI (it corresponds to notification regarding latest received... | AT command in SIM900A GSM/GPRS module to find out originating address of an SMS |
<p>Here are some that I know of:</p>
<p>Solidworks student edition:
<a href="http://www.solidworks.com/sw/education/cad-faq-students.htm" rel="nofollow">http://www.solidworks.com/sw/education/cad-faq-students.htm</a>
(Free for students who use a school's privately assigned password, otherwise $149)</p>
<p>AutoCAD St... | 1745 | 2013-08-14T11:48:18.233 | |design| | <p>I am planning to build a robot.</p>
<p>1) What free or low cost robot modelling tools exist.</p>
| What modelling tools are available to design a robot |
<p>(I know it's old but I still feel I need to add my solution)<br>
I have a similar issue, multiple units sending data and need a way to know what unit it is. I create a random unitId and save it in eeprom. If needed I can read it on serial port or by activating one at a time and check on the receiver side.<br>
I gues... | 1753 | 2013-08-16T08:40:44.710 | |arduino|microcontroller|communication| | <p>This might be a out of league question and may seems to be very odd.I am using multiple Arduino UNO boards over network and want to assign a GUID and Serial number to each board so that when ever they send any data to a central server, server is able to find which Device it is if we have assign name for each device.... | Assigning Serial number and GUID to a microcontroller |
<p>Well, I'll be darned. A serial number shows up in dmesg when you plug the thing in. I checked two boards that the number was different, so hopefully these are globally unique.</p>
<pre><code>me@mycompy:~/arducopter/MissionPlanner$ dmesg|tail ... | 1755 | 2013-08-16T15:48:38.817 | |arduino|ardupilot| | <p>I have several <a href="http://store.3drobotics.com/products/apm-2-5-kit">APM 2.5 boards</a> and need to identify them based on some globally unique hardware signature that does not change with programming.</p>
<p>Arduinos and atmel AVR chips in general <a href="http://forum.arduino.cc/index.php?topic=45104.0">do n... | Any globally unique signature in Ardupilot hardware, or Arduino in general? |
<p>Inaccuracy due to multipath bounces is negligible compared to inaccuracy due to seeing fewer satellites, as Matthew Gordon answers. So on a land vehicle, roof is best. Towbar is very poor.</p>
| 1765 | 2013-08-20T05:29:43.533 | |gps|ugv| | <p>I used to think that the higher GPS antenna position the better until I read the following on <a href="http://gpsd.berlios.de/faq.html#accuracy" rel="nofollow noreferrer">GPSd FAQ</a>:</p>
<blockquote>
<p>One <strong>common error is to place the GPS or antenna as high as possible</strong>.
This will increase multipa... | Place for GPS antenna on autonomous vehicle |
<p>I think you're misunderstanding the following two sentences from the abstract: </p>
<blockquote>
<p>(i) the first one is a fusion module which synthesizes line segments obtained from laser rangefinder and line features extracted from monocular camera. This policy eliminates any pseudo segments that appear from an... | 1774 | 2013-08-21T07:02:49.803 | |sensors|slam| | <p>In this <a href="http://www.mdpi.com/1424-8220/12/1/429" rel="nofollow">paper</a>, the author says that during SLAM process, pseudo segments that appear from any momentary pause of dynamic objects in laser data would make the map unsatisfied.</p>
<p>How is this caused? </p>
<p>If the dynamic object moved, won't l... | In SLAM, how does a laser range finder produce pseudo-segments from dynamic objects? |
<p>This design is definitely plausible, but there are some problems I can see.</p>
<ul>
<li>The maximum length is defined by the force the magnets can lift, since the ones lowest in the stack won't push the other ones up after some amount of them.</li>
<li>The magnets will want to get as far from the force as possible... | 1782 | 2013-08-26T12:47:32.267 | |actuator| | <p>So i got this idea waay back when i was in highschool as a kind of electromagnetic analogue to a biological muscle. it is basically a long stack of thin electromagnets connected in parallel.
<img src="https://lh5.googleusercontent.com/-DUdbOfkO9bI/UhtIXyefiII/AAAAAAAAB0c/vmkKU3K6rF0/w2350-h1762-no/IMG_20130826_1521... | Actuator design. plausible? |
<p>Finally Success:</p>
<p>I found that the Torobot USB board could be communicated with an Arduino serial driver. Conveniently this is available through opkg:</p>
<pre><code>opkg install kernel-module-cdc-acm
</code></pre>
<p>When the board is plugged in, it comes up as</p>
<pre><code>/dev/ttyACM0
</code></pre>
... | 1787 | 2013-08-28T19:13:55.500 | |control|microcontroller|rcservo|usb|embedded-systems| | <p>I'm trying to get the "Torobot" USB servo controller to work with Angstrom Linux on a Beagle Board XM.</p>
<p>The servo controller registers as a USB device. The device just takes simple text commands, but there is no TTY associated with it. So I'm not sure how to send commands to it.</p>
<p>Can I just send data l... | How do I send text to a Torobot USB device? |
<p>You can control brushless motors 2 ways</p>
<ol>
<li>control with a hall effect sensor <a href="http://scholar.lib.vt.edu/theses/available/etd-09152003-171904/unrestricted/T.pdf" rel="nofollow">http://scholar.lib.vt.edu/theses/available/etd-09152003-171904/unrestricted/T.pdf</a></li>
<li>sensorless(back emf) contro... | 1791 | 2013-08-29T19:25:26.487 | |motor|control|microcontroller|power|brushless-motor| | <p>I consider using a brushless outrunner motor, designed for helicopters, in my driving roboter. How can I control such a brushless motor with my micro controller? Of course I'll have a separate power source.</p>
<p>The roboter should be able to move forwards and backwards, so I need to control the motor in a way to ... | How to control a brushless motor? |
<p>The low distance between the top of the robot and the ceiling really restricts your options. It seems pretty much impossible to get a centralised overview of the whole room and work from there.</p>
<p>I'm not sure what kind of 'room' you are talking about and how much you can instrument it, but it might be an optio... | 1795 | 2013-08-31T21:49:19.597 | |localization|wireless|swarm| | <p>I have a 300cm x 300cm room with a 25cm high ceiling (yes twenty five centimeters). It contains 50 small wheeled robots (about 20cm x 20cm). A central computer will orchestrate the movements of the robots, using a wireless network to send position commands to them. The robots will perform their own closed loop posit... | Localizing a swarm of robots |
<p>It certainly sounds like the joystick is broken, but in Robotics, nothing is certain. Some things to try:</p>
<ul>
<li>Swap over the X and Y wires going to the Arduino. Which axis exhibits the problem now?</li>
<li>Disconnect the joystick from the Arduino, and power it up on its own. Using a multimeter, measure the... | 1797 | 2013-09-01T03:20:07.567 | |microcontroller| | <p><em>Outline:</em></p>
<p>I'm trying to work with an Arduino and Analog thumb stick to get values for a simple differential drive robot I'm working on. The <a href="http://www.plexishop.it/en/modulo-joystick-keyes-sjoys.html" rel="nofollow noreferrer">Keyes_Sjoys Arduino Joystick Module</a> I have in my possession i... | How do I Calibrate Analog Thumb stick? |
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