A step in the right direction

Well, that would explain it...

The reason that the quadruped robot was doing the "funky chicken" instead of walking smoothly was mostly due to a major bug in the gait angle calculations. The angle of the leg is the sum of the "shoulder" and "knee" joint angles -- but the angle commands to the knee servos weren't taking the shoulder angles into account. This caused a really inefficient, jerking motion, rather than the relatively smooth gait that was intended.

Oops.

It's fixed now (and has a new chassis and circuit board). The video shows it moving more-or-less in a straight line, but with a few modifications to the gait tables, it can turn, at least in shallow circles.

Next on the list:

• Rubber tips for the feet


• Improvements to the turning routines


• Turn-in-place functionality


• Reverse (basically, just run the gait tables in reverse order)


• Wireless control


• A second microcontroller to handle control and communications

Walker robot progress

Well, it moves. The gait algorithm is still handcoded instead of evolved (I'm working on finding a physics sim I can use for that), and is less than efficient -- but at least it's going in the right direction. The plan is for it to eventually be a hexapod -- maybe even with three degrees of freedom per leg -- but for now, it's a 2DOF quaduped. Once it's walking reasonably smoothly and efficiently, the plan is to make it remotely controllable and embed a video camera -- probably using XBeePro modules (from SparkFun, where else?).

The version in this video is still based on a cutaway plastic project box; it has since been moved to a proper chassis produced on the 3D printer. This doesn't yet do much for the gait, though.

More about the robot as the design evolves...