Redundant underactuated robot with multi-mode control framework

A method for controlling a jointed mechanism having a multi-axis robot and a passive pendulum system attached thereto and suspended therefrom, the method comprising:

• measuring rotational joint positions on the passive pendulum system using a plurality of position sensors;
• outputting position signals indicative of the rotational joint positions to a controller;
• and
• in response to the position signals, using the controller to selectively control motion of the robot in a plurality of control modes, including:
• a Cooperative Mode configured, in response to a physical interaction by a human operator with the end-effector, to cause a displacement in the pendulum system from an equilibrium position, and in which the controller is configured to command the robot to move in such a manner as to close the displacement and thereby return the pendulum system to the equilibrium position;
• and
• an Autonomous Mode configured to move the robot without a physical interaction with the end-effector by the human operator, wherein 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.

A jointed mechanism comprising:

• a horizontal overhead support beam;
• an actuated positioning mechanism connected to and configured to translate along the overhead support beam in two Cartesian degrees of freedom;
• a passive parallelogram arrangement attached to and suspended from the positioning mechanism, having an equilibrium position, and including:
• one or more position sensors configured to measure a joint angle on the passive parallelogram arrangement;
• parallel arms;
• a cross member connected to the parallel arms;
• and
• an end-effector attached to the cross member at a distal end of the passive parallelogram arrangement;
• and
• a controller in communication with the one or more position sensors, wherein the controller is configured to selectively control the passive parallelogram arrangement in a plurality of control modes, including:
• a Cooperative Mode configured, in response to a physical interaction by a human operator with the end-effector, to cause a displacement in the passive parallelogram arrangement from the equilibrium position, and in which the controller is configured to command the robot to move in such a manner as to close the displacement and thereby return the passive parallelogram arrangement to the equilibrium position;
• and
• an Autonomous Mode configured to move the robot without a physical interaction with the end-effector by the human operator, wherein 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.