Robotics Stack Exchange
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How to manage interrupts on an AVR?

I have a number of interrupt service routines on an AVR. These include interrupts for USART serial communication, timers, and SPI communication. For all of these, I use circular queues (using a start and end pointer, without boundary checking). Some…
ronalchn
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Computing the Jacobian Matrix -- chain rule?

I am learning about robot kinematics and the Jacobian matrix, and I'm trying to understand how to compute the Jacobian matrix given a kinematic chain, such as a robot arm. I understand the theory behind the Jacobian matrix, but I'm not sure actually…
Karnivaurus
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How do the PID parameters (Kp, Ki, and Kd) affect the heading of a differential driving robot when they are increased individually?

Question: A PID controller has three parameters Kp, Ki and Kd which could affect the output performance. A differential driving robot is controlled by a PID controller. The heading information is sensed by a compass sensor. The moving forward speed…
Dan
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Is this a singularity or incorrect implementation of inverse kinematics?

I at moment trying to compute the Q configuration that moves my robot from it current state described by this transformation matrix. with rotation 0.00549713 0.842013 -0.539429 0.999983 -0.00362229 0.00453632 0.00186567 -0.539445 -0.842019 …
Carlton Banks
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How can I improve ZED Camera precision?

I'm using Stereolabs ZED camera for my computer vision project. I did a small research about several sensors on the market and ultimately we decided to go with the ZED Camera. However I'm finding that the precision of the camera isn't that great.…
Ana Rodrigues
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Cannot disable sleep in passive mode for iRobot Create 2

I tried to disable sleep by pulsing the BRC pin low for one second every minute as suggested in the OI, but my Create 2 still goes to sleep after 5 minutes. My firmware is r3_robot/tags/release-3.2.6:4975 CLEAN The Create 2 is connected to an…
lejiang
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Regarding Kalman filter and estimating heading with magnetic compass

I have trouble estimating the heading when close to the "pivot" point of the compass, and could use some input on how to solve it. I have set up my angles to be from 0-360 degrees during the testing but will be using radians (-pi, pi) from now…
erltot
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Mobile robot path following using Model Predictive Control (MPC)

I'am trying to implement a path following algorithm based on MPC (Model Predictive Control), found in this paper : Path Following Mobile Robot in the Presence of Velocity Constraints Principle: Using the robot model and the path, the algorithm…
Inounx
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Adhesion for a heavy wall-climbing robot

I have come across a number of methods for developing wall-climbing robots. Suction Chemical Adhesion Gecko like hair adhesion Electroadhesion Which method would be the best for heavy robots (5kg+)? Are there any other methods that I have missed?
Tom Bamber
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What is the opposite of 'Antagonistic'?

A robotic joint is connected to two actuators, e.g. air muscles. One flexes the joint, while the other extends it. This arrangement is called 'antagonistic'. But what if I had an electric motor instead of the air muscles? In that case it can only…
Rocketmagnet
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Relationship between motor torque and acceleration

I am working on designing and building a small (1 1/2 lbs), 2-wheeled, differential drive Arduino-controlled autonomous robot. I have most of the electronics figured out, but I am having trouble understanding how much torque the motors will actually…
3871968
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Difference between an underactuated system, and a nonholonomic system

What's the difference between an underactuated system, and a nonholonomic system? I have read that "the car is a good example of a nonholonomic vehicle: it has only two controls, but its configuration space has dimension 3.". But I thought that an…
Karnivaurus
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Understanding Drift in Simultaneous Localization and Mapping (SLAM)

I am trying to understand the effect of drift in Simultaneous Localization and Mapping (SLAM). My understanding is that drift occurs because the robot tracks its position relative to a set of landmarks it is storing, but each landmark has a small…
Karnivaurus
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A Vector Field Histogram implementation in Python 2.7

I am trying to implement the Vector Field Histogram as described by Borenstein, Koren, 1991 in Python 2.7 using the SciPy stack. I have already been able to calculate the polar histogram, as described in the paper, as well as the smoothing function…
Danks C.
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How does the Makeblock threaded slot work?

I've been looking into a Makeblock robotics kit but have found no information on the web that comes from end-users, and one of the main advertised features is not clear to me: The slot threads shown below are straight, while the screw thread that…
Lucas Walter
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