A jointed mechanism includes a passive pendulum system attached to and suspended from the multi-axis robot. The system includes one or more position sensors configured to measure a joint angle on the pendulum system, at least one arm, and an end-effector attached to a distal end of the pendulum system. A controller implements a method to selectively control motion of the robot in a plurality of control modes. The control modes include a Cooperative Mode and an Autonomous Mode. The controller is configured to detect contact with the end-effector when operating in the Autonomous Mode, and to automatically initiate a control action in response to the contact. The pendulum system may be a parallelogram arrangement.