Showing posts with label robotic arm. Show all posts
Showing posts with label robotic arm. Show all posts

Wednesday, November 30, 2016

New Robotic Arm with Dynamixel servos

During the last year and some months I was getting my Master degree. As part of the embedded systems class, I created a Robotic Arm that could write some letters. Pretty cool, right?

The arm has 3 Degrees of Freedom (DOF) using Dynamixel RX-10 servos. I controlled the robot with a Beaglebone Black board with a cape that has a MAX485 chip. This chip converts UART TTL communications to RS-485 differential protocol (used on the Dynamixel servos). Also. I had to create some drivers for the controller to speak Dynamixel language (specific data frames format) on the communications bus.


For the arm to reach some point in 3D space, I programmed the kinematic equations that translated this desired point to a set of angles for the servos. I used the equations proposed by Núñez et al on the paper “Explicit analytic solution for inverse kinematics of Bioloid humanoid robot” (IEEE paper site).

Also I created two trajectories generators: one for free trajectories (moving from 1 point to another without care of the described trajectory) and one for linear  trajectories (moving between 2 points describing a straight line).

Finally I programmed the a routine on the robot using these trajectories functions, so it can describe some letters on a vertical plane. Here's a video of the robot:


The code for the project is found here: project link.
Also here is the technical document for the project (in spanish): document link

My github site: https://github.com/jcbrenes