Low cost robots for hobbyists and teaching

I’ve put together a list of (relatively) low-cost robots, arms as well as mobile robots (wheeled and flying). It is far from exhaustive but might be interesting. Contact me if you want to add something to the list https://docs.google.com/spreadsheets/d/1d-30kVKP12rhDcMgTbxNyM6GrXJ8uaCqL7DSosf2Pys/edit?usp=sharing

Dynamixel AX12A servos

These are very capable and handy devices for hobby robotics.  It has a pretty good manual, but here are some extra  notes and links that I’ve gathered.  This is a working document. Hardware details Circuit diagram (reverse engineered) for the

Direct computation of Jacobian from elementary transform string (ETS)

Given a robot kinematic model expressed as an elementary transform sequence (ETS), we show how to derive the manipulator Jacobian matrix.  This, combined with a standard minimization algorithm, is sufficient to perform numerical inverse kinematics without the need for Denavit-Hartenberg

Making V-REP work

V-REP is a great robotics simulator, but it’s been ages since I last used it.  I installed the latest version and ran into a few issues.  The solutions are below.  I’m using VREP 3.5 under Mojava. 1. File permissions V-REP

Understanding URDF with MATLAB

The Universal Robot Data Format (URDF) is an increasingly common way to represent the kinematic structure and visual appearance of robots. It is widely used in the ROS software ecosystem. A URDF file is an XML format file and a

EKF covariance matrix update for a new landmark

In the formulation for EKF SLAM (RVC chapter 6, appendix H) there is a special case when another landmark is discovered.  The state vector update is simple, concatenate the new landmark to the state vector, but the covariance update is

Roll-pitch-yaw angles

Updated 4 August 2018 There is a lot of confusion around the terms Euler angles and roll-pitch-yaw angles. This stems from quite different, seemingly authoritative, definitions in textbooks and papers.  There is no clear right and wrong here, authors are