Tuesday, 3 February 2015

Biped Hip Replacement


This is a quick post to show the latest updates to my biped development robot.

Since last time I’ve added another degree of freedom to each hip by adding two further Robotis servos. This has had a dramatic effect, allowing me to transition the centre of gravity easily over the desired foot before attempting to stride.

I’ve also moved the battery and main processor off board to reduce weight and allow me to use the full power of my PC. By driving the robot directly from my PC, rather than an Arduino, I’m able to perform real-time diagnostics. This in turn has allowed me to greatly refine the walking gait.

To communicate with my PC I’m using the Robotis USB2Dynamixel adapter. This is a great gadget that has a few of modes of operation – one of which allows me to convert USB signals to TTL used by the Dynamixel AX series and hook in external power for the servos.


In total, this biped now has 10 degrees of freedom: two in each hip; one in each knee; two in each ankle. To make turning easier, I could add another degree of freedom to each hip or ankle, which would enable rotation on the transverse plane. But for now, I’m happy the way it is.

It’s a pretty agile little beast now – check out the video below…