# All Questions

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### Modelling Point Clouds for Collision Detection in Gazebo

I am currently applying path planning to my robotic arm (in Gazebo) and have chosen to use an RRT. In order to detect points of collision, I was thinking of getting a Point Cloud from a Kinect ...
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### Pole-balancing / inverted-pendulum; is there a need for active control?

Not sure if I am posting this question in the correct community, as it relates primarily to reinforcement learning. Apologies early on if this is not so. In reinforcement learning many algorithms ...
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I what to convert .STL file to .mat to simulate object in m file in matlab. I am call the function like this way LoadSTL('F:\D Backup\najib\FYP\Dr istaz\matlab_sim_02\matlab_sim\quadfullprt.STL') ...
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### How can I increase the resolution of a PWM signal?

Say I have a motor and I want it to spin at exactly 2042.8878 revolutions per minute. Say I have a very precise sensor to detect the RPM of the motor to a resolution of 1/1000th of a revolution per ...
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### Setting up a gimbal with the Dji Wookong-M but using a separate transmitter and receiver

I just bought the Wookng-M for my multi copter and I was wondering if it is possible to have a two man system where one controls the main craft with one transmitter and the other controls the camera ...
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### How is Visual Servoing done?

how would one go about using Arduino and OpenCV using either Processing or Visual Studios? what does a visual servoing algorithm looks like ? i find no example of this using C++ or C#
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### Which brushless dc and propeller to choose?

I have a small bot(around 4-5kg with wheels) which is to be pushed without contact by another bot. I plan to do this using a bru and a propeller. I am having problems selecting the right combination. ...
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### Which USB interface for Android device I can use for motor driver

I am new to robotics, I will be controlling DC motors from Android device through USB For this I have selected L298N motor controller(After watching YouTube videos ) And got some DC motors I have no ...
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I'm building quadcopter from scratch, software is implemented on STM32F4 microcontroller. Frequency of main control loop equals 400Hz. I've though everything is almost finished but when i've mounted ...
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### Recommendation for 3D mechanism modeling and simulation software

I'm working on a robotic hand and I would like to simulate different joints and tendon insertion points before starting to actually build it. I've been googling and found things like Solidworks and ...
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### Fanuc Robot “Heat” control

My work has an older Fanuc robot ( Arc Mate 100-iBe RJ3iB, Fanuc AWE2 teach pendant with Powerwave 355M) and the old operator/programmer has left. I have taken over his job and cant find out how to ...
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### Getting pitch, yaw and roll from Rotation Matrix in DH Parameter

I've calculated a DH Parameter matrix, and I know the top 3x3 matrix is the Rotation matrix. The DH Parameter matrix I'm using is as below, from https://en.wikipedia.org/wiki/Denavit%E2%80 Above is ...
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### How to connect absolute encoder on the rotating shaft. Please see the three options?

Hi, Here I have added 2 options for connecting encoder on shaft. Motor, gearhead and shaft is connected using coupling. But where will be best place for encoder (To avoid backlash from coupling ...
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### What engineering problems needs to be solved to build a potato-peeling robot?

OK, let's say we have a tech request for a robotic system for peeling potatoes, and a design is as follows: One "arm" for picking up a potato and holding it, rotating when needed. Another "arm" for ...
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### What are the approaches for indoor robot positioning?

I understand that most of the self-driving cars solutions are based on Lidar and video SLAM. But what about robots reserved for indoor usage? Like robot vacuums and industrial AGVs? I see that Lidar ...
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### Lifting robotic leg with only one servo

Note before I start: I have not actually put anything together yet, i'm still just planning, so any changes that require a shape change or anything like that are accepted. I'm working on making a ...
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### Forward kinematic and inverse kinematic… When to use what?

I am not quite sure if I quite understand the difference between these two concepts, and why there is a difference between these two concept. Yesterday I was trying to compute the jacobian needed ...
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### Mapping between camera pose and image features in visual servoing

I have a robotic arm and a camera in eye-in-hand configuration. I know that there is a relationship between the body velocity $V$ of the camera and the velocities $\dot s$ in the image feature space ...
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### Relative orientation of two robots

Given two robot arms with TCP (Tool Center Point) coordinates in the world frame is: $X_1 = [1, 1, 1, \pi/2, \pi/2, -\pi/2]$ and $X_2 = [2, 1, 1, 0, -\pi/2, 0]$ The base of the robots is at: ...
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### Is there a way to disconnect and reconnect from a Create 2 that was streaming sensor readings without having to unplug/replug my USB-serial cable?

I am working with a Create 2 and I am executing a simple sequence like (in pseudocode): ...
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### How to build a fast quadcopter

im currently in a (risky) proyect that involves me building the fastest quad i can afford. Im trying to get something close to this extremely fast warpquad After reading a lot about quadcopters, as ...
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### Powering 6 servomotors requiring 6V and 2A each

The title pretty much says it all. I'm on a team that is currently building a robotic arm for the capstone project of my engineering degree, our design is similar to the Dobot (5 degrees of freedom). ...
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### What's the difference between feedback and feedforward control?

I'm reading from Astrom & Murray (2008)'s Feedback Systems: An introduction for scientists and engineers about the difference between feedback and feedforward. The book states: Feedback is ...
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### How can I reduce a motor's maximum current draw?

I have a motor with a stall current of up to 36A. I also have a motor controller which has a peak current rating of 30A. Is there any way I could reduce the stall current or otherwise protect the ...
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### Kinematic decoupling

Is kinematic decoupling of a 5DOF revolute serial manipulator also valid? The three last joints is a spherical joint. Most literatures only talks about decoupling of 6DOF manipulators. Thanks in ...
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### Dynamic simulation of compliant elements in quadruped robot

I have a preliminary design for a legged robot that uses compliant elements in the legs and in parallel with the motors for energy recovery during impact as well as a pair of flywheels on the front ...
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### Xaxxon Oculus Prime Platform: using a different SBC than the one sold by manufacturer

I am using the kit version Oculus Prime Mobile Platform sold by Xaxxon for a project and was planning to use and Odroid XU4 running ROS. But, the problem I faced was that the Odroid XU4 has a 32bit ...
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### Sizing high current power supplies for large robots

I'm a researcher in a lab that's starting work on some larger humanoid/quadruped robots as well as a quadcopter. Currently, we have several power supplies that have a max rating of 30V/30A and our ...
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### Angular velocity to translational velocity

I have a 3D point in space with it's XYZ Coordinates about some Frame A. I need to calculate the new XYZ coordinates, given the angular velocities of each axis at that instant of time about Frame A I ...
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### Automatic sliding window shutter

I want to build an automatic sliding window shutter and need help with part selection and dimensioning. Some assumptions: window width 1.4 m, slinding shutter weight 25 kg, max speed 0.07 m/s, max ...
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### Electronic circuit for heating nylon fishing line muscle

I'm trying to make artificial muscles using nylon fishing lines (see http://io9.com/scientists-just-created-some-of-the-most-powerful-muscl-1526957560 and ...
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I found CAD files for the Create on the ROS TurleBot download page (.zip), and shells on the gazebo sim page. Any ideas where the files for the Create 2 could be found?
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### Small IR distance sensor that works on black surfaces

Can anyone recommend an IR distance sensor that works on black surfaces? I'm looking for something to use as a "cliff" sensor, to help a small mobile robot avoid falling down stairs or off a table, ...
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### What is the easiest yet precise method one can make a track and a train [closed]

I would like to put a train on a track and control its movement with high precision left and right using a wireless controller. What is the best way to do it?
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### What are hardware components to build a modular robot which consists of several 5x5x5cm modules? [closed]

I am computer science student and I have no knowledge on robotics. In my project, I am trying to find controllers for modular robots to make them do specific tasks using evolutionary techniques. For ...
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### Torque / Current control for BLDC motors

I am working on a robotic application, and I want to control the torque (or current) of brushless DC motors. There are many BLDC speed controllers but I could not find anything related to torque or ...
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### Quadrotor - Control system, where to begin?

I am starting to assemble a quadrotor from scratch. Currently, I have this: Structure; an IMU (accelerometer, gyro, compass); 4 ESCs and DC motors; 4 propellers; Raspberry Pi to control the system, ...
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I have a Flip32 flight controller and a flysky fs-t6 receiver. I need to know the exact cord connection between the two. Possibly pictures to help me? Everything on my quad works except the ...
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### Is there a way to turn the sound off of a Roomba?

I am working with an iRobot Create 2 and I work with others around me. Whenever I turn the robot on, send it an OI reset command, etc., it makes its various beeps and noises. I would like to not have ...
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### iRobot Create 2: Can I load the code in instead of connecting cable? (new learner)

I am a new learner of iRobot. I am trying to program it to control the movement of the Create 2. After glancing through the existing project, I find most of them are based on sending commands to ...
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### Solar panel set rotation: How to achieve both vertical and horizontal rotation?

How can we achieve this kind of rotation to enable maximum trapping of solar rays during the day?
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### Need help for simple goal seeking using player/stage

I am newbie in Player/Stage. I want to implement a path planning algorithm in player/stage. But, it seems difficult to me as everything is new to me. For now, I just want to initialize my robot at a ...
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### How to use SLAM with simple sensors

What 2D SLAM implementations (preferably included in ROS) can be used with simple distance sensors like IR or ultrasonic rangefinders? I have a small mobile platform equipped with three forward ...
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### Moatech stepper motor salvage - unsure of pinout

I have salvaged a Moatech BL55K-M01 Stepper motor from an old printer and I'd like to play around with it, but I'm unsure of how to use the pinout listed on the board. Pinout reads: 24V 24V GND GND ...
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### What charger to use with my ZIPPY Compact 6200mAh 4s 40c Lipo MultiRotor Battery

Hello I am trying to build a Quadcopter for a school project and I need to finish quick before our mission trip because I was asked to finish it before then so that I could take it. But I am having a ...
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### Denavit Hartenberg parameters - 3DOF articulated manipulator

I am trying to solve a forward kynematics problem for a 3DOF manipulator. I am working with the Robotics Toolbox for MatLab created by Peter Corke and after calculte the DH parameters and introduce ...
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### Relationship between earth frame attitude and acceleration for a quadcopter

For a quadcopter, what is the relationship between roll, pitch, and yaw in the earth frame and acceleration in the x, y, and z dimensions in the earth frame? To be more concrete, suppose roll ...
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### I can't get motors to turn with Raspberry pi

I want to turn some motors using my raspberry pi. I am able to turn an LED on and off using the 3.3V GPIO pin. For the motors, I tried using a L293D chip as per the instructions on this link. What ...