- Yeah, that'd be me.
"Compliance control" is a make-believe spring-mass-damper system that's superimposed on the robot's joints to make them act springy. You need a force sensor, too, usually at the robot wrist. When the sensor goes off, the commands to the robot are modified based on the sensed force. This prevents a very strong robot from smashing through a more delicate object that it would like to touch.
The Spud is newly fascinated with his stacking cups. We stack them for him, and he likes to touch them just a little so that the stack wobbles but doesn't fall down. He is, essentially, tuning his own compliance controller.