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<p>The important thing to remember about a <a href="http://en.wikipedia.org/wiki/PID_controller" rel="nofollow">PID</a> control loop is that each term is intended to dominate control at different times during a move.</p>
<p>The proportional term is intended to dominate and provide a larger torque (or in your case spee... | 1 | 2012-10-23T19:38:18.867 | |soccer|control| | <p>Imagine programming a 3 wheel soccer robot. What type of controller would you use for spinning it? P? PID?</p>
<p>The goal for this controller is that it should make the robot stand in a defined angle ( 0 degree ) and turn back if rotated by hand or other robot. </p>
<p>I use stepper motors for my robot and not se... | What is the right approach to write the spin controller for a soccer robot? |
<p>Don't, instead get yourself some <a href="http://www.pololu.com/catalog/category/51" rel="nofollow noreferrer">decent motors</a> and drive them via an h-bridge like you'll find on this <a href="http://arduino.cc/en/Main/ArduinoMotorShieldR3" rel="nofollow noreferrer">motor shield</a>.</p>
<hr>
<p><img src="https:/... | 2 | 2012-10-23T19:42:56.030 | |control|rcservo| | <p>I've got some hobby servos (<a href="http://www.servodatabase.com/servo/power-hd/hd-1501mg">Power HD 1501MGs</a>) and I'd like to be able to control them (via an Arduino) so they will either go to the angle I set, or put them in a 'free running' mode, where the load will take them wherever it goes.</p>
<p>Is this e... | How can I modify a low cost hobby servo to run 'freely'? |
<p>You should use an ARM. Then you can run full linux or android and have access to powerful libraries, high-level functional languages, and a package manager and community. You can use gcc or LLVM, and a modern debugger like gdb.</p>
<p>ARMs used to be too expensive and/or too big, but nowadays you can get an ARM for... | 4 | 2012-10-23T19:43:47.140 | |microcontroller|arduino|raspberry-pi| | <p>I am looking for a starting point for my project, preferably using popular systems (ones there is a lot of support for). I have an Arduino Uno, a Raspberry Pi, and a lot of willpower :) Anyone here built a project using the systems above?</p>
<p>Observation: I'd like to start with a simple line-following vehicle an... | Good Microcontrollers/SOCs for a Robotics Project |
<p>A simple option for approximate neighbor search in non-euclidean spaces is using $sqrt(N)$ samples in the search. This has been implemented in OMPL, see <a href="http://ompl.kavrakilab.org/classompl_1_1NearestNeighborsSqrtApprox.html" rel="nofollow noreferrer"><code>ompl::NearestNeighborsSqrtApprox< _T ></code... | 5 | 2012-10-23T19:43:48.463 | |motion-planning|rrt| | <p>I'm trying to implement a nearest-neighbor structure for use in an RRT motion planner. In order to do better than a linear brute-force nearest-neighbor search, I'd like to implement something like a kd-tree. However, it seems like the classical implementation of the kd-tree assumes that each dimension of the space c... | Nearest-neighbor data structure for non-Euclidean configuration space |
<p>Just to add to <a href="https://robotics.stackexchange.com/a/125/40">user65's good answer</a>.</p>
<p>Rapid rotation about a horizontal axis will come from a large difference between the thrust produced by opposite motors. The larger the difference, the greater the rotation rate. So motors that can produce much mor... | 25 | 2012-10-23T20:34:39.070 | |quadcopter| | <p>There are many sites which explain briefly this problem and even propose combinations. I however would like a much more detailed explanation. What is going to give my quad the most agility? Do I need bigger motors/props in a heavy quad to achieve the same level of agility than in a lighter quad?</p>
<p><strong>EDIT... | How to choose the right propeller/motor combination for a quadcopter? |
<p>The robotics team I lead at NCSU has implemented the ability to drive our holonomic robot using a Leap motion controller. Here's a <a href="https://www.youtube.com/watch?v=BDgmRz1Gb7Q#t=0" rel="nofollow">demo video</a>.</p>
<p>Our codebase is in Python, so we used the Python Leap library, which was quite simple and... | 39 | 2012-10-23T21:12:46.500 | |kinect|input| | <p>As in the title, I'd like to implement gesture recognition on my robot and I'm looking for the pros and cons between the Kinect and the Xtion - and also if there are any other sensible options available.</p>
<p>I'm thinking of the following, but open to other suggestions:</p>
<ul>
<li>Accuracy</li>
<li>Price</li>
... | I'd like to use gesture based input for my robot. What are the pros and cons between the Xtion Live and the Kinect? |
<p>There is very little difference between a robotic off road vehicle and a normal vehicle with a driver. What kind of vehicles are suitable for off-road conditions?</p>
<p>Why - tractors of course!</p>
<p><img src="https://i.stack.imgur.com/ho71x.jpg" alt="Tractor"></p>
<p>Look at those bad boys! Great for all arou... | 42 | 2012-10-23T21:18:17.723 | |wheel| | <p>I'm looking to potentially build an autonomous robot that will frequently venture off road, and remain autonomous for up to 6 hours at a time. I've found limited information however about the best tyre tread for this purpose, what could be most suitable?</p>
<p>I'm especially looking for a tread pattern that won't ... | What tyre tread would be best suited to an off road robot expected to deal with frequently muddy conditions? |
<p>The simplest controller is a linear state feedback controller. There are essentially 4 different states that you need a gain for. These are tilt angle, tilt rate, speed and position.</p>
<hr />
<p><strong>LQR</strong> (linear quadratic regulator) is a method to design these gains (after obtaining a linearized state-... | 43 | 2012-10-23T21:22:09.763 | |control|gyroscope|balance|two-wheeled| | <p>Is there a good, popular and reliable algorithm I can use by taking input from a gyroscope and using this to control two independant wheels to keep such a balanced robot reliably upright? I'm looking for an algorithm that will let me use it to drive a robot around as well as keep it upright when stationary. The abil... | What algorithm should I use for balancing a two wheeled robot using a gyroscope? |
<p>Lithium Ion Polymer batteries are probably your best bet. </p>
<ol>
<li>They will present the least amount of magnetic interference (followed by Alkaline... NiCD interferes the most). </li>
<li>Unlike the regular lithium ion cells (which are usually round), these ones will stack nicely. </li>
<li>I hope you'll c... | 46 | 2012-10-23T21:31:31.177 | |underwater|battery|auv| | <p>I'm looking to build an underwater glider robot that will need to remain autonomous for long periods of time, perhaps even months. Power draw should be minimal, and I'm thinking of including some form of charging device (such as a solar charger) however I'd also like the battery capacity to be large enough so I don'... | What's the most effective type of rechargeable battery when taking into account size / weight / Ah? |
<p>It will take a lot to shake components off of a PCB/PWB so for the most part it should be safe if you make sure that the mounting is correct. One thing that people forget is that if there is vibration then there may also be flex, and even tiny amounts of flex transmitted into a PWB can be damaging. FR4 is stiff an... | 48 | 2012-10-23T21:46:04.840 | |electronics|protection| | <p>It's common for components on some types of robots to experience large environmental stresses, one key one being vibration. Is this something I need to worry about with typical electronics and other sensitive components, or not really? If it is, then how do I secure such components? </p>
<p>I've heard of two main p... | How can I best protect sensitive components against damage through vibration? |
<p>I actually work as a programmer for the tractors that bit-pirate mentioned.</p>
<p>There are several ways mentioned that can get you more accurate results. It depends largely on your application and what you are trying to accomplish.</p>
<ol>
<li><p><a href="http://en.wikipedia.org/wiki/Wide_Area_Augmentation_Syst... | 49 | 2012-10-23T22:01:52.997 | |localization|gps| | <p>Obviously GPS is the most obvious and accessible technology for obtaining a locational "fix" for a robot at any particular time. However, while it's great sometimes, in other locations and situations it's not as accurate as I'd like, so I'm investigating whether there's a relatively easy way to improve on this accur... | What's the most accurate way to obtain a locational fix using GPS? |
<p>To do SLAM, you will need a relatively good estimate of position.</p>
<p>Robots that use laser scanners can make do with just odometry, because the data is relatively accurate, and the scanner data can be used to help localize in subsequent time steps.</p>
<p>Ultrasound sensors are very fuzzy, they generally have ... | 53 | 2012-10-23T22:44:20.217 | |slam|localization|gps|mapping|acoustic-rangefinder| | <p>Ultrasound sensors are incredibly cheap these days which makes them a popular choice for many hobbyist robotic applications, and I'd like to use a bunch of them (say 10) around a robot with an algorithm to build a rough map of an area (as the robot explores it.) I'm not interested in dealing with moving objects at t... | What algorithm can I use for constructing a map of an explored area using a number of ultrasound sensors? |
<p>The problem with the Dynamixel servos is that they're trapped in an insulating plastic jacket. There is no convection, and no good thermally conductive material to let heat out efficiently.</p>
<p>The first thing I'd suggest is to get some air flow. Moving air has a surprising ability to cool something hot. You har... | 55 | 2012-10-23T22:49:37.247 | |otherservos|heat-management|cooling| | <p>Hobby servos are generally not sufficient for real robotics for a number of reasons: Quality, precision, range of motion, torque, etc.</p>
<p>Meanwhile, industrial servos, such as ABB, Emerson, GE, etc, are generally both heavy and expensive, and not suitable for small-humanoid scale actuation. Similarly, building ... | Adding external heat sinking to a Dynamixel RX-24F servo? |
<p>Temperature is a very simple number to measure and is a good aggregation of all the other factors since a weakening motor will be driven harder.</p>
<p>Generally a motor that is about to fail will be significantly hotter than the rest of the motors.</p>
| 57 | 2012-10-23T22:51:07.573 | |sensors|failure|motor| | <p>What characteristics can I look for which could be reliable early warning signs that a DC motor on my robot, say one used for the drive, could be failing? I'm looking for an answer that deals in terms of sensors rather than manual inspection, so a circuit could be constructed to warn of a potential failure before it... | How can I detect if a DC motor on a robot is starting to fail? |
<p>Mathematically, the fact that you now have rotation (mostly) eliminates that parameter as a possible control parameter. Basically you'd have to redesign your algorithm to accept a large and variable angular velocity component while still using angular velocity in your feedback. The less noisy this is, the better t... | 60 | 2012-10-23T23:02:36.980 | |two-wheeled|stability| | <p>With two wheeled robot <a href="http://www.pages.drexel.edu/~dml46/Tutorials/BalancingBot/files/nxt_icon.jpg">like this one</a>, I have managed to stabilize it while keeping it stationary. This was done using a digital feedback control system by reading the position of the wheels to determine position, and the natur... | Is it possible to both move and stabilize a two wheeled robot with no gyroscopes? |
<p>You might want to check out FRC 1114 Simbotics' website, especially <a href="http://www.simbotics.org/resources/mobility" rel="nofollow noreferrer">http://www.simbotics.org/resources/mobility</a> . The FTC team I coach has used that as a starting point for their own work. </p>
| 65 | 2012-10-24T00:17:07.893 | |mobile-robot|design|movement|wheel|first-robotics| | <p>I'm part of a <a href="http://usfirst.org" rel="noreferrer">FIRST Robotics</a> team, and we're looking into using <a href="http://en.wikipedia.org/wiki/Mecanum_wheel" rel="noreferrer">Mecanum wheels</a> for our robot.</p>
<p>What are the advantages and disadvantages of using Mecanum wheel versus regular ones? From ... | Calculating the efficiency of Mecanum wheels |
<p>You are going about this incorrectly. The reason why pololu is telling you to connect the two pins is because the sleep pin has a pullup resistor on their breakout board. </p>
<p>Connecting reset to the sleep pin is equivalent to connecting the reset pin to high.</p>
<p>You can achieve your goal by connecting re... | 75 | 2012-10-24T04:13:21.397 | |arduino|logic-control|stepper-motor|stepper-driver| | <p>I've got this driver: <a href="http://www.pololu.com/catalog/product/1182" rel="nofollow noreferrer">http://www.pololu.com/catalog/product/1182</a></p>
<p>... a A4988 stepper motor driver carrier</p>
<p><img src="https://i.stack.imgur.com/MPEI5.png" alt="enter image description here"></p>
<p>I'm attempting to con... | Using an Arduino to control an ON / OFF connection between two pins |
<p>Have a look at the paper <a href="http://www.dynalloy.com/pdfs/TCF1140.pdf" rel="nofollow noreferrer">Technical Characteristics of Flexinol Actuator Wires</a>.</p>
<p>What you'll want to do is devise a structure that leverages the available contraction of the nitinol wire to achieve the desired stroke and force for... | 85 | 2012-10-24T10:21:01.003 | |mobile-robot| | <p>For a robotic gripper arm we are designing for factory floor use on very small components, we propose to use electrically activated Shape Memory Alloy (SMA) wire harnesses for actuation. </p>
<p>The device being designed is akin to Pick & Place machines used for circuit assembly, but moves over an aircraft-hang... | Shape Memory Alloy wire for robot gripper arm actuation: How to vary grip pressure? |
<p>How about Omnidirectional wheels?</p>
<p><img src="https://i.stack.imgur.com/DMSs2.jpg" alt="Omnidirectional wheel"></p>
<p>You could drive the sphere on two pairs of such wheels, with each pair driven by one motor. This would give you two axis control of the sphere. I.E. you can drive forwards or sideways.</p>
<... | 88 | 2012-10-24T10:41:24.373 | |otherservos|mobile-robot|stepper-motor| | <p>Design goal is to have a mobile robot that operates on 3 large casters, essentially 2 to 4 inch diameter steel ball bearings, that are motorized. No other mechanism would touch the surface. The robot should thus be able to move in any XY direction on a flat surface, with steering being achieved by varying the speed ... | Mechanical design for motorized spherical caster wheels |
<p>Whilst the two answers in place focus on mechanical noise (which is what I think you are asking about) there is also, of course, electrical noise which manifests itself as Electro-Magnetic Interference (EMI or also known as EMC)</p>
<p>Anything that contains a motor is likely to generate a level of EMI... normally ... | 91 | 2012-10-24T13:42:36.257 | |motor|actuator|noise| | <p><a href="http://www.youtube.com/watch?v=ZHJf365p_zw">Many robots</a> and other mechanical devices produce the signature whirring noise as they move, <a href="http://www.youtube.com/watch?v=67CUudkjEG4">some</a> produce less. What makes the difference? What restrictions a silence requirement places on a robot?</p>
| What determines the amount of noise an actuator produces? |
<p>It sounds like you're observing the symptom of "lost bytes". There are several different things that can cause an AVR to lose bytes.</p>
<p>It sounds like you are <em>guessing</em> that it's losing bytes when new bytes are coming in while the buffer is full. While there are several remedies to fix or at least ameli... | 99 | 2012-10-24T15:07:52.240 | |microcontroller|avr|interrupts| | <p>I have a number of interrupt service routines on an <a href="https://en.wikipedia.org/wiki/Atmel_AVR" rel="nofollow">AVR</a>. These include interrupts for <a href="https://en.wikipedia.org/wiki/Universal_asynchronous_receiver/transmitter#Synchronous_transmission" rel="nofollow">USART</a> serial communication, timers... | How to manage interrupts on an AVR? |
<p>Maybe too expensive for a home project, but the MIL-DTL-38999 series connector (available from <a href="http://www.glenair.com/interconnects/mildtl38999/" rel="nofollow">Glenair</a> and many other suppliers) is the connectro of choice for military equipment</p>
<p>OK, it fails your "they are not simple plug-in conn... | 100 | 2012-10-24T15:17:21.853 | |wiring| | <p>If you have used connectors for signal wiring for any length of time, you may find that they are unreliable.</p>
<p>Specifically, I find these to be unreliable when used for a long time, with a number of disconnections and re-connections:</p>
<p><img src="https://i.stack.imgur.com/RDJQV.jpg" alt="enter image descr... | What connectors are most reliable? |
<p>If you are not near the robot but require an e-stop, you'll want to consider a watchdog circuit watching a remote signal. The circuit keeps an eye out for a pulsing signal and, if the signal stops pulsing, activates the e-stop circuitry. You want to have this as close to a physical circuit as you can, which means th... | 112 | 2012-10-24T22:08:20.767 | |mobile-robot|errors| | <p>Emergency stops are obviously a good idea on most robots, how should they be wired? What systems should be killed immediately, and what should stay working?</p>
| How should emergency stops be wired? |
<p>This subject is covered quite nicely in the <a href="http://www.probabilistic-robotics.org/">Probabilistic Robotics</a> book by Thrun et. al. I don't have a direct reference, but there are some of his papers (such as <a href="http://www.cs.cmu.edu/~thrun/papers/thrun.robust-mcl.ps.gz">Robust Monte Carlo Localization... | 113 | 2012-10-24T22:10:07.020 | |sensors|noise| | <p>Range sensors (for example sonar, infrared, and lidar) are notoriously noisy. How can I characterize the noise characteristics to include these in a probabilistic localization sensor model?</p>
| How to model the noise in a range sensor's return? |
<p>In generally there is difference between 4 and 8 neighborhood in many algorithms which are <strong>graph based</strong>, (such as A*, MRF(markov random field), edge detection algorithm and etc). </p>
<p>This depend on computational complexity, time, performance or some things like this (Trade off/balance between... | 117 | 2012-10-25T02:01:30.993 | |motion-planning|artificial-intelligence|planning| | <p>In graph-based planning (say, A*), states are connected to their neighbors. How should one decide whether to connect to the 4 neighbors or the 8 neighbors? What are the pros and cons of each approach?</p>
| What is the difference between 4-point and 8-point connectivity in graph based planning? |
<p>The reason why you can't see the nxtOSEK logo, is that the enhanced firmware looks the same as the regular firmware, but with several performance and feature enhancements. It isn't specific to nxtOSEK.</p>
<p>To check if the firmware installed properly, visit the <strong>Settings</strong> menu on the NXT, and then ... | 118 | 2012-10-25T02:41:22.373 | |mindstorms|nxt| | <p>I am attempting to upload a custom firmware to a Lego Mindstorms NXT and am having issues.</p>
<p>First of all, I'm attempting to use <a href="http://lejos-osek.sourceforge.net/">nxtOSEK</a>, which would let me run C++ programs on it. The problem is, everytime I put it into firmware update mode, the download doesn... | Properly flashing the firmware on a Lego Mindstorms NXT |
<p>Just to add a little to <a href="https://robotics.stackexchange.com/a/120/37">ronalchn's excellent answer</a>:</p>
<p>Changing the weight distribution in the robot in a way that doesn't change the position of the centre of mass will affect the <a href="http://en.wikipedia.org/wiki/Moment_of_inertia" rel="nofollow n... | 119 | 2012-10-25T04:45:29.487 | |mobile-robot|design|stability|wheeled-robot| | <p>When designing a standard 4 or 6 wheel robot, is it better to have the weight distributed primarily in the center of the robot, or over the wheels, or is there no difference?</p>
<p>Specifically, which weight distribution will make the robot less likely to tip over?</p>
| Is it better to have weight distributed over the wheels or the center of the robot? |
<p>One good solution is to do BOTH. A design I use place "hard" real time functions on a small micro controller, tight servo control loops and such. Then there is another CPU that is larger, running Linux and ROS. I let ROS handle the higher level tasks and the uP handle things like controlling a stepper motor or ru... | 128 | 2012-10-25T09:49:05.213 | |software|platform|real-time| | <p><strong>Edit:</strong> I don't know why, but this question seems to be confusing many people. I am aware of when/where/why/how to use real-time. I am interested in knowing whether people who have a real-time task would actually care enough to implement it in real-time or not.</p>
<p>There's no need to mention why r... | How mature is real-time programming in robotics? |
<p>It's been a while since I've used the AVR, but there where two libraries which would do what you are looking for. Unfortunately ATMEL doesn't provide proper firmware libraries themselves (as e.g. STM does).</p>
<ul>
<li><p><a href="http://www.procyonengineering.com/embedded/avr/avrlib/" rel="nofollow">Procyon AVRli... | 131 | 2012-10-25T14:06:19.100 | |software|microcontroller|i2c| | <p>I Have an ATmega16 mc which is master on the i2c and a ATMega8 mc which is slave on the i2c.</p>
<p>I have connected the two mcs' sda and scl ports to each other alongside a pullup resistor.</p>
<p>Now I want to read a register from the ATMega8 using the ATMega16. </p>
<p>The problem is that I don't want to assig... | Connecting two microcontrollers using I2C |
<p>Kiva uses a multi-agent system to control its fleet of robots and movable shells. Their website provides a <a href="http://www.kivasystems.com/solutions/software/" rel="noreferrer">high-level overview of their system architecture</a> and there's also a <a href="http://www.slideshare.net/devbp/kiva-system" rel="noref... | 142 | 2012-10-25T21:02:12.810 | |mobile-robot|industrial-robot| | <p>What kind of sensors and algorithms are the mobile robots of <a href="http://www.kivasystems.com/">Kiva Systems</a> equipped with? </p>
| Technology behind Kiva Systems mobile robots |
<p>You do not want to use stainless steel with linear bearings because that type of steel is not hard enough and the bearing will wear grooves into the rod. You want high carbon steel with hardness greater than HRC 60.</p>
| 146 | 2012-10-26T00:30:03.880 | |reprap|3d-printing|linear-bearing| | <p>For the 3d printer <a href="http://www.reprap.org/wiki/Prusa_Mendel_Assembly">RepRap Prusa</a> there are several rails (smooth rods) that guide the printer head on the different axises. The printer head uses several linear bearings to glide along the rails. </p>
<p>There isn't any specification on what kind of mate... | What rail material is best used for linear bearings? |
<p>You should read the paper published by Microsoft research on the actual algorithm behind the human motion tracking.</p>
<p>Real-Time Human Pose Recognition in Parts from a Single Depth Image, Shotton et. al,
<a href="http://research.microsoft.com/apps/pubs/default.aspx?id=145347">http://research.microsoft.com/apps/... | 148 | 2012-10-26T04:48:02.503 | |kinect| | <p>I am not sure if this has been tried before but I am trying to use <a href="http://en.wikipedia.org/wiki/Kinect" rel="nofollow noreferrer">Kinect</a> and detect gestures made by the <a href="http://en.wikipedia.org/wiki/Nao_%28robot%29" rel="nofollow noreferrer">Nao robot</a>.</p>
<p>I have made a Kinect applicatio... | Detect Nao robot in Kinect |
<p>I wanted to create a submerged water pump as part of school science project. I really had a hard time in making a normal DC motor and its shaft in making water proof. i failed miserably.
Later i came with an idea. I removed the shaft and magnets from the motor . i removed the coil and attached magnet in the shaft. ... | 150 | 2012-10-26T07:23:58.103 | |motor|underwater|auv|protection| | <p>Whenever building an aquatic bot, we always have to take care to prevent leakages, for obvious reasons. Now, holes for wires can be made watertight easily--but what about motors? We can easily seal the casing in place (and fill in any holes in the casing), but the part where the axle meets the casing is still left u... | Preventing leaks in motor shafts for underwater bots |
<p>It would be nice if we could tell the compiler the range and precision of each fixed-point input variable (perhaps no two having the radix point in the same location), and it would automagically -- at compile time -- use the correct range and precision and rescaling operations for the intermediate values and final v... | 154 | 2012-10-26T09:45:37.170 | |microcontroller|c| | <p>Often we use microcontrollers to do things in our robots, but need to make some calculations in decimal. Using floating point variables is <strong>very</strong> slow, because a software floating point library is automatically included (unless you have a high-end microcontroller). Therefore, we generally use fixed po... | Fixed point arithmetic on microcontrollers |
<p>I assume that you are looking for an IMU that provides you with an orientation estimation. The complete package is usually called an Attitude and Heading Reference System (AHRS). What really is the most defining criteria is your budget. Getting above 3 degrees/s should be within reach though. </p>
<ul>
<li><p>We ha... | 155 | 2012-10-26T09:58:11.633 | |ros|imu|odometry|gyroscope|ugv| | <p>At our lab, we have a several "Kurt" type robots (about the size of a Pioneer, six wheels, differential drive). The built-in gyroscopes are by now really outdated; the main problem is that the gyroscopes have a large drift that increases as the gyro heats up (the error is up to 3°/s). We mainly use the IMU (inertial... | How to choose a good IMU for a wheeled robot? |
<h1>If you want to have a accurate PID coefficient:</h1>
<ul>
<li>Get your statistic actuator data (i.e. <kbd>collecting input voltages</kbd> + <kbd>encoder pulses</kbd> in a const frequently (<code>0.01sec</code>) time for <code>20secs</code> as a <code>3</code>x<code>2000</code> matrix)</li>
<li>Get transfer function... | 167 | 2012-10-26T19:11:31.040 | |control|pid|tuning| | <p>Tuning controller gains can be difficult, what <strong>general</strong> strategies work well to get a stable system that converges to the right solution?</p>
| What are good strategies for tuning PID loops? |
<p>I know this is an old question but I will just add a bit to the currently existing answers. First, this is a very complex problem that everyone is trying to tackle, including google with their <a href="https://www.google.com/atap/project-tango/" rel="noreferrer">Tango project</a>. In general, to localise indoor you ... | 172 | 2012-10-27T05:11:23.017 | |localization|gps|sensors|slam| | <p>Using an IMU a robot can estimate its current position relative to its starting position, but this incurs error over time. GPS is especially useful for providing position information not biased by local error accumulation. But GPS cannot be used indoors, and even outdoors it can be spotty.</p>
<p>So what are some m... | Absolute positioning without GPS |
<p>This isn't a published study, but many people use the <a href="http://en.wikipedia.org/wiki/Technology_readiness_level" rel="nofollow">Technology Readiness Level (TRL)</a> system to assess the state of technologies. </p>
<p>Granted, it doesn't really tell you <em>when</em> a technology might reach a particular stag... | 184 | 2012-10-27T21:47:42.403 | |research| | <p>Robotics has always been one of those engineering fields which has promised so much, but is taking a long time to deliver all the things that people imagine.</p>
<p>When someone asks: "How long before we have [X] type of robots?" Are there any resources we can call upon to try to calculate a rough answer. These res... | Robotics Trends |
<p>A co-worker and I once implemented a <a href="https://en.wikipedia.org/wiki/Simplex_algorithm" rel="nofollow noreferrer">simplex algorithm</a> for on-the-fly tuning of the PID parameters of a current control loop for a motor. Essentially the algorithm would modify one parameter at a time and then collect data on som... | 210 | 2012-10-28T19:03:57.037 | |control|pid|automatic|tuning| | <p>I have a simple servo system that uses a PID controller implemented in an MCU to perform the feedback. However, the properties of the system change dynamically, and so the PID parameters can never be tuned for all circumstances.</p>
<p>My robot is a light weight arm with back-drivable electric motors, similar to th... | How can I automatically adjust PID parameters on the fly? |
<p>Many recent Android devices, such as the Nexus 7, support USB On The Go (OTG) which is a fancy way of saying that 'USB Host Mode' is supported. In these cases, with the right cable which can be had for less than $1, any compatible USB device can be used. You don't need a specialty version of the Arduino that has h... | 213 | 2012-10-29T05:30:30.627 | |actuator| | <p>Smart phones these days typically come with a gyroscope, accelerometer, compass, camera, and GPS sensor all on board. They also usually have a connection to the internet with Wifi and mobile data networks. I've seen many cases of using a phone as a remote control for a robot, but to me, it seems like the phone itsel... | How can I integrate a smart phone with my robotics project? |
<p>It sounds like your enthusiasm is in the right place, but I think you're trying to make intelligent design decisions without knowing what you're designing. This is good! These are all things to be worried about when designing a robot, whether as big as your shoe or as big as your car. But they aren't what you sho... | 215 | 2012-10-29T08:02:34.200 | |arduino|microcontroller| | <p>I'd like to start making robots and tinkering with microcontrollers. Where do I start, and what do I need?</p>
<p>I'd like to make my own robots. I'm comfortable with programming (assembly and C) so I've got that part covered, but my electronics/circuits knowledge is a little weak. I have no idea what material to s... | Starting out advice on making robots and tinkering with microcontrollers |
<p>This has been merged as of six weeks ago:</p>
<p><a href="https://github.com/ros/ros_comm/commit/8a1f92fc0c888099fe47005f609883601b7d8d72#diff-1" rel="nofollow">https://github.com/ros/ros_comm/commit/8a1f92fc0c888099fe47005f609883601b7d8d72#diff-1</a></p>
| 229 | 2012-10-30T12:59:16.537 | |ros|python| | <p>In ROS, I cannot get [ERROR] logs to print in red when I use python. How can I make them appear in red instead of black?</p>
<p><br></p>
<p>For example, the following Python:</p>
<pre><code>rospy.logerr("No analog input received.")
</code></pre>
<p>produces this output in <strong>black</strong>:</p>
<blockquote... | Red [ERROR] output in python in ROS |
<p>As of 2020/2021, the answer is yes, ROS runs on Raspberry Pi.</p>
<p><a href="https://roboticsbackend.com/install-ros2-on-raspberry-pi/" rel="nofollow noreferrer">https://roboticsbackend.com/install-ros2-on-raspberry-pi/</a>
<a href="https://www.youtube.com/watch?v=AmuLiA840fA" rel="nofollow noreferrer">https://www.... | 230 | 2012-10-30T14:09:21.773 | |ros|raspberry-pi|wifi| | <p>Can <a href="http://www.ros.org/wiki/">ROS</a> run on a Raspberry Pi?</p>
<p>ROS is resigned to run on a network of machines, with different machines, even different cores on the same machine doing different jobs. Can one of those machines be a Raspberry Pi?</p>
<p>I am considering using an R-Pi as the <a href="ht... | Can ROS run on a Raspberry Pi? |
<blockquote>
<p>At 1st glance:</p>
<p>115200 == 115.2 bits per millisecond == ~12.8 bytes per millisecond
(assuming 1 stop bit)</p>
<p>Is that a valid way to calculate timing for
serial transmissions?</p>
</blockquote>
<p>Very simplistically, this is OK - but don't forget any start and parity bits also... | 237 | 2012-10-30T17:41:41.563 | |microcontroller|serial|rs232| | <p>A common scenario is to have a PC that sends commands to a microcontroller via RS232. My PC program is sending commands (each of which are composed of multiple bytes) as fast as it can to a small robot. The microcontroller on the robot is a Parallax Propellor.</p>
<p>I have noticed that if I don't process bytes q... | How to calculate serial speed and buffer requirements for PC to microcontroller communications? |
<p>In industry, there is a strong preference for low maintenance brush-less motors over relatively high maintenance brushed motors. While the former may me more expensive in terms of the motor itself and the drive electronics, the reduction in the term long cost of maintenance usually out weighs the extra capital cost.... | 254 | 2012-11-01T21:00:11.233 | |brushless-motor|servomotor| | <p>I have a robot that uses brushed motors in its servo system. These are Maxon 3W motors, with 131:1 planetary gearboxes. The motors are controlled by a PIC microcontroller, running a 1kHz PID controller. The servos are for a low speed high torque application. There is significant backlash between the sensor and the m... | Should I switch my servo system from brushed to brushless motors? |
<p>Parrallax offers some products in the space you are looking, but I think what you really want to do is go to hobby king; </p>
<p><a href="http://www.hobbyking.com/hobbyking/store/__657__501__Multi_Rotors_Parts-Flight_Controller.html" rel="nofollow">http://www.hobbyking.com/hobbyking/store/_<em>657</em>_501__Multi_R... | 255 | 2012-11-01T22:47:12.250 | |uav|kit| | <p>I'm really new to robotics, however I am a programmer familiar with several different languages. I don't have a ton of money to spend and I was wondering what is a really good starter kit. </p>
<p>My criteria is for the kit to be inexpensive and <strong>powerful</strong>, in that its functionality is extensible -- ... | What UAV kit(s) would be suitable for a beginner roboticist with programming experience? |
<p>As other people mentioned, an RF beacon will probably be difficult and vision is definitely a viable option. The common difficulty with vision-based solutions is that they are computationally expensive, making it difficult to be done on-board. </p>
<p>You can try using the PixArt IR tracking sensor from a Nintendo ... | 256 | 2012-11-02T00:19:32.710 | |localization|quadcopter|gps| | <p>I want to use an RF beacon to localize my quadcopter for autolanding, when GPS is not precise enough, for example, when my driveway is only 10 feet wide, and the GPS is only showing 20-30 ft. accuracy (with a proverbial lake of lava on either side). The quadcopter would use the GPS to fly to the rough location until... | Quadcopter Localization Beacon |
<p>The diagram you show looks like it would produce a pretty rough trapezoidal Back-EMF. I'm assuming that the gates that are at 100% are the lower legs of the motor drive bridge. I can't think of a reason you would want to do this. In general you want the gate voltage of the return leg to be the complement of the gate... | 261 | 2012-11-03T00:56:08.123 | |brushless-motor|pwm| | <p>I have seen waveforms for driving a brushless motor.</p>
<p><img src="https://i.stack.imgur.com/UHO04.jpg" alt="Brushless motor waveform"></p>
<p>I guess this is the waveform used for the simpler block commutation. But if I want to do sinusoidal waveforms, what does the PWM signal look like now? Is there a need to... | What do the commutation waveforms look like for a brushless motor? |
<p>Practical point of view: Traction of wheel</p>
<p>Traction of the wheel (friction between wheel and surface) is proportional to the mass of the robot. Small mobile robots with low mass can have low wheel traction, and can easily slip on the surface, friction co-efficient of the wheel and surface area of contact bet... | 262 | 2012-11-03T06:16:39.650 | |mobile-robot|design|dynamics| | <p>Do mobile and/or autonomous robots become more or less effective the bigger they get? For example, a bigger robot has bigger batteries, and thus bigger motors, whereas a smaller robot has the exact opposite, making it need less energy, but also have smaller motors. Is there any known theorem that models this?</p>
| Effectiveness of a Mobile Robot In Relation To Mass |
<p>Capacitors are used with motors in two different ways. Sometimes the same motor will have both techniques applied, and be associated with two significantly different-looking capacitors.</p>
<ul>
<li><p>When motors with brushes are running normally, the motor brushes produce sparks, which cause noise "from DC to day... | 267 | 2012-11-03T16:58:44.830 | |motor|protection| | <p>I've seen many motors having capacitors attached in parallel in bots. Apparently, this is for the "safety" of the motor. As I understand it, all these will do is smoothen any fluctuations--and I doubt that fluctuations can have any adverse effects on a motor. Apparently these protect the motor if the shaft is being ... | Why are capacitors added to motors (in parallel); what is their purpose? |
<p>With a bit of additional research I have found one other project very similar to the OpenServo project. They are called supermodified servos. Some of the web sources are not available anymore, but there is the source for the project, which is quite advanced on google code and on github:</p>
<ul>
<li><a href="http:/... | 274 | 2012-11-05T08:29:56.787 | |otherservos|i2c| | <p>Some years ago, there where some projects that provided hardware and software to perform modifications on standard hobby servos to convert them to digital servos, with all the advantages that come with it. </p>
<ul>
<li><a href="http://openservo.com/" rel="nofollow">OpenServo</a> is a little outdated, and does not ... | Low-cost servo with digital control interfaces? |
<p>A Kalman Filter is an algorithm that is commonly used in UAVs to fuse multiple sensor measurements together to provide an "optimal" estimate of the position and/or orientation of the UAV. For example, a Kalman Filter can fuse accelerometer, gyro and magnetometer measurements with a velocity estimate to estimate the... | 277 | 2012-11-05T23:18:26.770 | |kalman-filter|uav| | <p>I am designing an unmanned aerial vehicle, which will include several types of sensors: </p>
<ul>
<li>3-axis accelerometer</li>
<li>3-axis gyroscope </li>
<li>3-axis magnetometer</li>
<li>horizon sensor</li>
<li>GPS </li>
<li>downward facing ultrasound.</li>
</ul>
<p>A friend of mine told me that I will need to pu... | Why do I need a Kalman filter? |
<p>There are two broad approaches:</p>
<ul>
<li>analytic solutions, given an end-effector pose, directly compute the joint coordinates. In general the solution is not unique, so you can compute a set of possible joint coordinates. Some may cause the robot to hit things in its environment (or itself), or your task mi... | 299 | 2012-11-08T00:59:40.857 | |inverse-kinematics|kinematics|joint|robotic-arm| | <p>The forward kinematics of a robot arm can be solved easily. We can represent each joint using <a href="http://en.wikipedia.org/wiki/Denavit%E2%80%93Hartenberg_parameters">Denavit–Hartenberg</a> transformation matrices.</p>
<p>For example, if the $i^{th}$ joint is a linear actuator, it may have the transformation ma... | How can the inverse kinematics problem be solved? |
<p>short answer; no you really need to do things quite a bit differently.</p>
<p>long incomplete answer;
Let me give you some psuedo code appropriate for robotC, that puts you on a better path. First, do not use tasks - this is NOT what robotC tasks are for. They could be made to work, maybe, maybe not (and you need qu... | 309 | 2012-11-08T12:07:23.013 | |mobile-robot|software|two-wheeled|robotc| | <p>I've been doing a lot of reading lately about <a href="http://en.wikipedia.org/wiki/Subsumption_architecture" rel="nofollow">Subsumption Architecture</a> and there are a few different ways people seem to advocate. </p>
<p>For instance some people use a global "flag" variable to have a task take control. Others use ... | Correct way to use Subsumption Architecture with Robot C |
<p>That script is calling "mex" but it's getting pdfTex "mex" tool instead of the Matlab compiler. </p>
<p>Before running that script you need to adjust your <code>PATH</code> environment variable to put the Matlab binaries before your system ones. Assuming your Matlab binaries are located in <code>/opt/matlab/bin</... | 323 | 2012-11-08T19:23:49.510 | |mobile-robot|software|slam|ros| | <p>Is anyone able to help me out getting IPC-bridge working on my ubuntu lucid installation (with matlab 2012a)? I'm not being able to finish the last step on here (Compiling the messages folders): <a href="https://alliance.seas.upenn.edu/~meam620/wiki/index.php?n=Roslab.IpcBridge#Installation" rel="nofollow">https://a... | IPC-Bridge problem |
<p>I have built a lot of walking robots, in my experience if you can't get it to walk by programming a gait you are not going to get it to learn because you don't know what it is supposed to do and the search space is too large. Using an Arduino you may be able to get it to fine tune some movements iff you can define g... | 327 | 2012-11-08T23:07:14.817 | |arduino|microcontroller|machine-learning|walking-robot| | <p>I'm building a 4 legged robot (quadruped) with 3 Degrees of freedom per leg.
The goal of my project is to make this robot able to learn how to walk.
What learning algorithms will I need to implement for it to work?</p>
<p>I'm using an <a href="http://www.arduino.cc/" rel="nofollow">Arduino Uno</a> for the microcont... | Learning Algorithms for Walking Quadruped |
<p>As you probably guessed from the lack of answers, subsumption architecture is not an active area of research any more. Most papers on this have been published in the late 80's / early 90's.</p>
<p>This doesn't mean that subsumption architecture is dead; it has been very influential in robotics, and it's still used ... | 354 | 2012-11-10T20:26:08.600 | |control|research| | <p>I am interested in learning more about <a href="http://en.wikipedia.org/wiki/Subsumption_architecture" rel="noreferrer">subsumption architecture</a>. I have read a number of books that talk about the idea but none of them go into great detail. I have also read a fair number of Dr. Brooks papers on the topic however ... | Is subsumption architecture still an active area of research? |
<p>I am not sure what type of robot you have but i have been doing robocup rescue line for a few years now. I have come to realise that if you want to follow a line well using PID is a good option. Let me expand on this. If you imagine two light sensors on either side of the line you would want them to be of equal valu... | 361 | 2012-11-11T19:48:28.747 | |machine-learning|artificial-intelligence|reinforcement-learning|line-following| | <p>I am considering programming a line following robot using reinforcement learning algorithms. The question I am pondering over is how can I get the algorithm to learn navigating through any arbitrary path?</p>
<p>Having followed the <a href="http://webdocs.cs.ualberta.ca/~sutton/book/the-book.html" rel="noreferrer">... | Programming a line following robot with reinforcement learning |
<p>If you consider e.g. a robotic arm, the inverse kinematics tell you how to choose the arm's joint angles to move the arm to some position and orientation where you want it to be. </p>
<p>In contrast to determining the forward kinemactics of some mechanism, determining it's <em>inverse kinematics</em> is usually har... | 369 | 2012-11-12T18:50:20.770 | |inverse-kinematics|reinforcement-learning|machine-learning| | <p>Are <a href="http://en.wikipedia.org/wiki/Inverse_kinematics" rel="noreferrer">inverse kinematics</a> and <a href="http://en.wikipedia.org/wiki/Reinforcement_learning" rel="noreferrer">reinforcement learning</a> techniques contending techniques to solve the same problem viz. movement of robotic manipulators or arm?<... | Are inverse kinematics and reinforcement learning competitive techniques? |
<p>This is a much bigger project than you think, and processing power is the least of your concerns. You may want to skip straight to step #9. Otherwise, here are some questions you need to ask yourself, based on my experience of building something very similar as a hobby project (I used a desktop PC for processing):</... | 380 | 2012-11-13T09:34:55.917 | |software|inverse-kinematics|robotic-arm|rs232| | <p>I want to build a robot arm that'll be approximately 1.25 meter long and will be able to lift up to 2 kilograms. It'll have 6 dof and it is an expensive project. And most importantly, i am the only programmer in this brand new robotics facility of ours. :)</p>
<p>The robot that i want to build will be led by Invers... | Processor and command interface preference for a robot arm |
<p>You can greatly simplify the problem in most common cases:</p>
<ul>
<li>A lot of "commercial grade" IMus (e.g. Xsens) have very noisy accelerometers. Don't even bother fusing them to get speed, the odometry is already order of magnitudes better. The only usable data the IMU is going to provide is the pitch and roll... | 382 | 2012-11-13T10:51:35.660 | |sensors|kalman-filter|sensor-fusion| | <p>My team and I are setting up an outdoor robot that has encoders, a commercial-grade <a href="http://en.wikipedia.org/wiki/IMU" rel="noreferrer">IMU</a>, and <a href="http://en.wikipedia.org/wiki/Global_Positioning_System" rel="noreferrer">GPS</a> sensor. The robot has a basic tank drive, so the encoders sufficiently... | How to fuse linear and angular data from sensors? |
<p>The short answer is yes, this can work. The long answer is "Yes, but you need to do a lot of sensor fusion".</p>
<p>The technology you're after was conceived about 5 years ago, the academic work is here:
<a href="https://people.csail.mit.edu/wojciech/MoCap/index.html" rel="nofollow noreferrer">https://peo... | 390 | 2012-11-13T23:27:22.663 | |imu|sensor-fusion|hri| | <p>I have been using the Cyberglove to control a humanoid robot hand, but found it disappointing as it doesn't measure the posture of the human hand very accurately.</p>
<p><img src="https://i.stack.imgur.com/T7TYQ.png" alt="Cyberglove"></p>
<p>I have been wondering about the possibility of using Inertial Measurement... | Can I use IMUs to improve the position/posture measurement of fingers in a "data glove"? |
<p>There's a good, if slightly overly optimistic study done by KPMG and the Center for Automotive Research called <a href="http://www.kpmg.com/US/en/IssuesAndInsights/ArticlesPublications/Documents/self-driving-cars-next-revolution.pdf" rel="nofollow">Self Driving Cars: the Next Revolution</a>. You'll be seeing more a... | 403 | 2012-11-14T16:52:39.187 | |ugv| | <p>I am aware of the legislation's in Nevada, but what is happening with the technology currently. When is it expected to be commercialized ?</p>
| What is the current state of the Google Self Driving Car Project? |
<p>As Rocketmagnet mentioned, just because a motor is rated at 2.5 W doesn't mean it will be pulling 2.5 W <em>all the time</em>. Most robots have at most 1 or 2 servos that are running at full power at any one time; the rest have very low mechanical loads (and therefore pull much less electrical power) or are "off" an... | 416 | 2012-11-14T21:36:19.967 | |servomotor|design|power|rcservo| | <p>I apologize if this question may sound a little vague. I am working on a robotics project that will contain 27 servos of various sizes and I am having trouble figuring out how they should be powered.</p>
<p>I was hoping to use several (3-6) 5 W 18650 battery boxes to power them, but the smallest motors would use 2.5... | What is the best way to power a large number (27) servos at 5 V? |
<p>To get relative displacement between two time instants all you need to do is integrate the values given off by the accelerometer (twice for linear displacement) and gyro (once for angular displacement).</p>
<p>Due to measurement errors, which can many times be adequately modeled as Gaussian (you might have to estim... | 419 | 2012-11-14T23:06:21.523 | |software|imu|deduced-reckoning|artificial-intelligence| | <p>I'm building a walking robot that will need to know when it moves forward. I'm using on-board intelligence and I plan on using accelerometers, gyros, and magnometers (if needed) to be able to detect if the robot moves forward. The problem is, I dont know how to program an Internal Navigation System or an IMU. What ... | How do you implement an INS from an accelerometer and (optionally) gyros and a magnetometer? |
<p>These are matrix-vector math libraries. They are related to inverse kinematics only because inverse kinematics involves matrices, vectors, and math. If you need an implementation of an inverse kinematics library, that is a different question. But any of those would be fine for doing the required math, once you solve... | 431 | 2012-11-15T12:23:57.450 | |inverse-kinematics|programming-languages| | <p>I'm planning to write an Inverse Kinematics controlled 6 dof virtual robot for Android. I did some research on packages avaliable and couldn't choose the right one which will satisfy my needs on this project. I've seen a work with Eigen in C++, and used it, it was just fine. But since i'm not so experienced in Java,... | Inverse Kinematics in Java |
<p>Holding torque has nothing to do with driving the amount of torquelead screws. The holding torque rating is only for when the Axis is in stationary position holding. What you want it to maximize your stepper driver amperage with a stepper that has the same or a little less amp rating</p>
| 446 | 2012-11-16T21:03:22.347 | |stepper-motor|reprap| | <p>I have a handful of 31.2oz-in stepper motors (<a href="http://www.mouser.com/Search/ProductDetail.aspx?R=HT17-268Dvirtualkey55010000virtualkey834-HT17-268D">Mouser.com - Applied Motion: HT17-268D</a>), and I was curious if they would be big enough to run a 3D printing/cutting/etching type (think RepRap) of machine. ... | How much torque do I need for a CNC machine? |
<p>You can use an <a href="http://www.ebay.co.uk/itm/391201790274?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT" rel="nofollow noreferrer">RC battery checker</a>, </p>
<p><a href="https://i.stack.imgur.com/39992.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/39992.jpg" alt="Cell ca... | 453 | 2012-11-18T05:44:20.077 | |battery|troubleshooting| | <p>In our lab we use LiPo batteries to power our quadrotors. Lately we have been experiencing stability issues when using certain batteries. The batteries seem to charge and balance normally and our battery monitor indicates they are fine even when putting them under load. However when we attempt to fly the quadrotor w... | How can one determine whether a LiPo battery is going bad? |
<p>Speaking about navigation among moving obstacles, look at Jur van den Berg thesis. Also Lavalle provided a tutorial at ICRA12 <a href="http://msl.cs.uiuc.edu/~lavalle/icra12/" rel="nofollow">http://msl.cs.uiuc.edu/~lavalle/icra12/</a> and the videos are here <a href="http://techtalks.tv/events/105/" rel="nofollow">h... | 469 | 2012-11-20T04:54:02.230 | |navigation| | <p>I would like to have a better understanding of work in the field of "Navigation Among Movable Obstacles". I started off with <a href="http://www.ri.cmu.edu/pub_files/pub4/stilman_michael_2007_1/stilman_michael_2007_1.pdf" rel="nofollow">Michael Stilman's thesis under James Kuffner</a>, but that has not yet sated my ... | Is there a working implementation of "Navigation Among Movable Obstacles" for a bi-pedal robot? |
<p>Communication latency is another reason why USB1.1 or USB2.0 is not always a good replacement for RS232. Data on USB1.1 or USB2.0 bus is formatted into 1ms or 125us frames respectively, which forces minimum receive to transmit latency equal to two frame periods (often more in practise). This is an important consider... | 474 | 2012-11-20T15:46:48.243 | |rs232|usb| | <p>RS232 is not popular as it used to be and is mainly replaced by USB [<a href="http://en.wikipedia.org/wiki/RS-232#Role_in_modern_personal_computers" rel="nofollow noreferrer">wikipedia</a>]. Problems such as mentioned in <a href="https://robotics.stackexchange.com/q/331/158">this question</a> doesn't help its reputa... | USB instead of RS232 |
<p>The "math" way to do this is to generate a speed/torque curve for your stepper at its given voltage, and determine the maximum force that will be applied to the object in motion (in this case, the largest force is likely to be acceleration).</p>
<p>Note that most hobby 3d printers are so flimsy that the frame bendi... | 478 | 2012-11-21T10:59:55.920 | |control|stepper-motor|tuning| | <p>As an industrial roboticist I spent most of my time working with robots and machines which used brushless DC motors or linear motors, so I have lots of experience tuning PID parameters for those motors.</p>
<p>Now I'm moving to doing hobby robotics using stepper motors (I'm building my first <a href="http://tvrrug.... | How can I optimise control parameters for a stepper motor? |
<p>I use @narayan's approach to implement my particle filter:</p>
<pre><code>new_sample = numpy.random.choice(a=particles, size=number_of_particles, replace=True, p=importance_weights)
</code></pre>
<p>a is the vector of your particles to sample, size is the count of particles and p is the vector of their normalized ... | 479 | 2012-11-21T15:36:22.960 | |localization|particle-filter| | <p>I understand the basic principle of a particle filter and tried to implement one. However, I got hung up on the resampling part. </p>
<p>Theoretically speaking, it is quite simple: From the old (and weighted) set of particles, draw a new set of particles with replacement. While doing so, favor those particles that ... | Particle filters: How to do resampling? |
<p>I'd stick with a <a href="https://beagleboard.org/bone" rel="nofollow noreferrer">BeagleBone</a> for the brains plus an <a href="https://www.sparkfun.com/products/11286" rel="nofollow noreferrer">Arduino Leonardo</a> for the brawn. This gets you a full computer capable of running Linux or Android with 512 MB of RAM... | 494 | 2012-11-24T10:28:54.920 | |nxt| | <p>I'm interested to build Robot from my imagination, and I was looking to purchase a robotic kit.</p>
<p>I find the Lego Mindstorm NXT 2.0 really interesting for many reasons : You can plug whatever brick you want, and you can develop in the language you want.</p>
<p>I am a developer, and the use of this kind of rob... | More powerful alternatives to Lego Mindstorm NXT 2.0? |
<p>While there are specific outlets, as the other answers show, you shouldn't underestimate plain old <a href="http://youtube.com" rel="nofollow">YouTube</a>. Most research labs and companies simply host their videos there (e.g. <a href="https://www.youtube.com/user/mitmedialab" rel="nofollow">MIT</a>, <a href="https:/... | 502 | 2012-11-24T21:27:31.757 | |publications| | <p>Robots are somewhat videogenic, and the old saying "show me, don't tell me" is especially applicable.</p>
<p>But of course, a video is not a <em>question</em>, so it doesn't fit the Stack Exchange format. Maybe video links would be more suitable in a CodeProject post. It just seems like this board hits the right ... | Is there a place for posting "look at what I did" videos? |
<p>There are really nice on-line <a href="http://www.societyofrobots.com/calculator.shtml" rel="nofollow">calculators on societyofrobots</a> including a <a href="http://www.societyofrobots.com/RMF_calculator.shtml" rel="nofollow">robot motor factor calculator</a> that could be helpful for you.</p>
| 504 | 2012-11-24T21:43:42.497 | |motor| | <p>I am making a 2 wheel drive robot.</p>
<p>Suppose I know that my robot is going to weight x kg when finished and I know the diameter of the wheels y (geared motors will be connected directly to the wheels). I can choose from several geared motors and I know the peak torque of each motor and the idling speed.</p>
<... | Choosing motors for 2 wheel drive robot |
<p>I think your best ally will be Google. A quick search for "arduino juniper cutedigi" led me to the <a href="http://www.cutedigi.com/wireless/wifi/juniper-wifi-shield-for-arduino-based-on-gainspan-module.html" rel="nofollow">manufacturer's website</a>, which includes a good amount of documentation and sample code und... | 511 | 2012-11-25T18:30:52.343 | |arduino|electronics|wifi| | <p>I recently got an arduino wifi shield known as "juniper" (I believe it was by cutedigi). I've tried to find code examples, but when I saw code, it was un-commented and very little explained, I could really use a tutorial or some sample code with a good explanation, can anyone help me find a place to start? I found a... | Where can I find a tutorial or sample code for the Juniper WiFi Arduino Shield? |
<p>One thing to watch out for is that many of the additive or extrusion-based 3D printers will leave small gaps between the beads of plastic that they lay down. Even if you polish the surface, the interior will be very poor optically.</p>
<p>You may want to look at <a href="http://en.wikipedia.org/wiki/Selective_lase... | 520 | 2012-11-26T07:34:40.657 | |3d-printing|manufacturing| | <p>A lot of awesome optics projects like hacking cameras and projectors become possible with CAD lens modelling software<sup>1</sup>, if we can also easily prototype the lenses we design.</p>
<p>What are some materials and additive or subtractive 3D fabrication strategies that can make a clear lens with strong refract... | Is it practical to 3D print a refractive lens? |
<p>One way is to find the Jacobian using Perturbation method.</p>
<p>Basically, you compute forward kinematic matrix and find each entry through numeric differentiation</p>
<p>for each f(θ1+Δθ, θ2, θ3...)
subtract f(θ1, θ2, θ3)
divide by Δθ</p>
<p>θ1, θ2+Δθ, θ3...
subtract f(θ1, θ2, θ3)
divide by Δθ</p>
<p>and so on</p... | 521 | 2012-11-26T08:00:05.007 | |inverse-kinematics|kinematics| | <p>When computing the Jacobian matrix for solving an Inverse Kinematic analytically, I read from many places that I could use this formula to create each of the columns of a joint in the Jacobian matrix:</p>
<p><span class="math-container">$$\mathbf{J}_{i}=\frac{\partial \mathbf{e}}{\partial \phi_{i}}=\left[\begin{arr... | Computing the Jacobian matrix for Inverse Kinematics |
<p>It looks like the Rainbowduino 3.0 uses an ATmega328, so first be sure to choose a board that's using that.</p>
<p>If that doesn't solve the problem, try looking at this <a href="http://www.seeedstudio.com/wiki/Rainbowduino_v3.0" rel="nofollow">wiki article about the Rainboduino v3.0</a>.</p>
| 530 | 2012-11-26T22:14:31.157 | |software|arduino|programming-languages| | <p>OK, not really robotics, but has anyone been able to upload to a Rainboduino v3.0 using the Arduino IDE? I can't seem to figure it out, and there is virutally no documentation online. I followed <a href="http://www.anyware.co.uk/2005/2012/01/17/getting-started-with-arduino-rainbowduino/" rel="nofollow">this blog ent... | Rainbowduino 3.0 - Arduino IDE fails to upload |
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