contact-rich manipulation

Contact-rich manipulation covers tasks where the robot is constantly touching, rubbing, and bumping against things, and where those contacts make and break over and over as the job goes on. Think of plugging in a charger, threading a bolt, snapping two Lego bricks together, or fitting a peg into a tight hole. These are not the smooth reach-through-empty-air motions of moving an arm from A to B; they are jobs done by feel, where the parts press, slide, catch, and seat against each other the whole time.

The reason these tasks are hard is that, against stiff parts, a tiny misalignment produces a large force. If a peg is a hair off-center as it enters a hole, it jams and the robot feels a sharp push-back; force it and something breaks. So a robot cannot just blindly follow a planned path — it has to be compliant, meaning it gives a little when it feels resistance, the way your own hand wiggles a key that does not quite slide into a lock. This softness, plus listening to the forces through the fingertips or wrist, lets the robot search out the right alignment instead of crashing through.

Because position alone is never accurate enough at this scale, contact-rich manipulation blends motion with force sensing and yielding: push gently, feel where it catches, slide along the surface, let the contact guide the part home. Insertion and assembly — the bread and butter of factories — are the classic examples, and getting robots to do them as smoothly as a human worker remains an active frontier.