BeagleBone Dynamixel AX12 Interface - Part 2

 

I have made some progress interfacing the Dynamixel AX-12 servo with the Beaglebone.

In this video I have breadboarded a sparkfun logic level converter to convert the Beaglebone's 3.3v UART logic to the Dynamixel's 5v logic and a Tri state bus buffer to convert the Beaglebone's UART signals to half duplex.

I have run into one snag however...
It seems that the Beaglebone's UART are only able to properly work up to 115.2k baudrate by default. If anyone knows how to adjust the maximum baudrate of the Beaglebone's UART to 1M or even 3M baud please comment!

BeagleBone Dynamixel AX12 Interface - Part 1

AX12 Darwin Feets!

AX12 Darwin Update

After quite a few weeks I am finally getting back into this project.

Over the week I have finished most of the mechanical parts except the feet and a few arm pieces. This weekend I will be working on wiring up the servos and hopefully start to tune the the gait motions that up until now has only worked in simulations.

Biped Robot Leg Prototyping

Heavily inspired by the Darwin OP robot by from Robotis and RoMeLa at Virginia Tech I have started A biped robot project.

So far I have constructed a prototype leg and have begun developing the software while finalising the mechancial aspects of the robot. The prototype leg design I am working with is a copy of the stock Bioloid Premium Type A configuration as seen below.

In this video I am demonstrating a simple pose, capture and playback program to test the range of motion in the leg and to make sure everything moves as expected. The program asks the user to pose the leg into two positions. Then does some simple linear interpolation between the poses, looping forever.



In the next video I have a test program that demonstrates the inverse kinematics algorithm I have developed for the leg. In this program I am able to enter 4 values (x,y,z,rotation) to position the center of the foot in relation to what would be the center of the robot.

AX-12 Monitor

AX-12 Monitor is a simple terminal program I am working on to interact with Dynamixel AX-12 Robot Actuator bus.

This program is still very much a work in progress but I plan on making the source along with a little bit of documentation available when it is finished.

AVR Dynamixel AX-12 Controller Running IK and Gait Engine

I was able to get my IK functions and gait engine running on my AVR micro.

Below is a short video of the front left leg running an 8 step ripple gait in the forward direction.

AVR Dynamixel AX-12 Controller

Over the last few days I have been working on my AVR microcontroller board that I posted about a while back.

So far I have been able to implement the Dynamixel AX-12 communication protocol and have successfully commanded an AX-12 servo.

I am now in the process of porting over my IK and gait engine from python running on my PC to C on the micro.

As always you can download my code here.

Joining The Dark Side

Or at least that is what they call it over in the Trossen Robotics community...

I have acquired a set of 14 Dynamixel AX-12 servos by Robotis along with Bioloid Bus Interface board by HUV Robotics to allow easy PC to AX-12 bus communication.