Remote Center of Motion: Surgical Robot Trocar Pivot (2D)

Every laparoscopic robot has to solve the same geometry problem before it can worry about tremor filtering or motion scaling: the instrument shaft must pivot through one fixed point in space — the trocar puncturing the abdominal wall — no matter how the surgeon swings the handle. This 2D companion renders that Remote Center of Motion (RCM) constraint as a side elevation plus a top-down wall-plane inset. Drive pitch, yaw and insertion depth with RCM engaged and the entry point never moves; switch it off and the same commands are applied through a rigidly-mounted joint instead, and the wall-crossing point drags sideways with every degree, spiking a live lateral-force estimate and a reddening stress ring around the port.