A master-slave system that includes a first manipulator supporting a first end effector; a second manipulator supporting a second end effector; an input device configured to concurrently receive from a hand of an operator a first movement command to effect a desired movement of the first end effector and a second movement command to effect a desired movement of the second end effector; and a processor configured to determine a desired movement of the first and the second end effectors in response to the first and second movement commands received from the input device respectively.