Abstract: A control unit for controlling motion of a surgical robot arm, the control unit being configured to receive an input signal from a surgeon input device for controlling the surgical robot arm and send an output signal to the surgical robot arm to cause motion of the surgical robot arm, the control unit being further configured to: detect a clash in respect of the surgical robot arm; in response to detecting the clash, place a limitation on the motion of the surgical robot arm; receive an input signal from the surgeon input device for controlling the surgical robot arm and send an output signal to the surgical robot arm so as to control motion of the surgical robot arm in accordance with the limitation.

Abstract: A control system and a method for controlling a surgical robotic system are provided. The surgical robotic system comprises a surgical robot arm. The surgical robot arm comprises a plurality of joints by which its configuration can be altered. An input is received which indicates a desired motion of the surgical robot arm when the surgical robotic system is operating in a mode in which the surgical robot arm is controlled in accordance with an objective. The objective is to control a particular part of the surgical robot arm to have a desired position and/or orientation. The control system determines that the desired motion of the surgical robot arm would cause a limit to be exceeded. In response to determining that the desired motion of the surgical robot arm would cause the limit to be exceeded, a control signal is generated for controlling the surgical robot arm, and the generated control signal is sent to the surgical robot arm in order to control the surgical robot arm.