Gregory Barsamian creates (non-robotic) 3-dimensional animated pieces using a motorized frame, a series of incrementally changing sculptural objects, and a strobe light calibrated to flash in sync with the rotation of the motor. The strobe makes these objects almost impossible to capture in video; they work much better in person. There's one at the Museum of the Moving Image in New York.
There are many more videos by Arthur Ganson, one of America's foremost kinetic sculptors, on his youtube channel. Again: not robotic pieces, just beautifully designed and fabricated, wonderfully balanced machines.