impedance control

Impedance control is a way of telling a robot not where to be, but how to feel when something pushes on it. Most simple control insists the robot hold an exact position no matter what, so if it meets a wall or a person it shoves through stubbornly and can do damage. Impedance control instead makes the robot's hand (its end-effector — the gripper or tool at the tip) behave like a chosen spring-and-damper: push it and it gives way by an amount you decide, then eases back. You are programming a relationship between the force the robot meets and the motion it allows, rather than nailing it to one spot.

Think of it as dialing the softness of a handshake. Set the virtual spring stiff and the robot holds firm, yielding only slightly under load — good for precise work. Set it soft and the robot becomes gentle and forgiving, flowing around contact — good for working beside people or sliding a part into place by feel. The damper part controls how bouncy versus syrupy that yielding feels. Crucially, you do not measure force and react to it after the fact; you shape the whole dynamic behaviour so the right give-and-take emerges naturally on contact.

Because it takes a motion deviation as its input and produces a contact force as its response, impedance control is the natural choice when a robot must touch an uncertain, changing world — opening a door, polishing a surface, or being safe around humans — where rigid position commands would be brittle or dangerous.