Why a robot assembling delicate parts needs to regulate how hard it pushes, not just chase a coordinate.
Most industrial robot motion is position control: the controller is told exactly where the end-effector should be, and its whole job is to drive the actual position to match that commanded position as accurately and quickly as possible — using whatever force or torque the joints can produce to get there. That's the right mode for pick-and-place, welding, and most general motion, where the goal is simply "get the tool to this exact location." But a pure position controller has no built-in awareness of, or limit on, the force it applies while chasing that target. When a task involves real physical contact — inserting a delicate part into a tight-tolerance hole, deburring a surface, any assembly step where the exact contact geometry can't be predicted perfectly — that blind spot stops being harmless and starts being a way to break things.