System and method for using joint torque feedback to prevent oscillation in a flexible robotic manipulator

A control system for controlling movement of an object, the system comprising:

• a joint torque sensor for sensing joint torque at an adjacent joint located adjacent to the object;
• a position sensor for sensing a position of the object at said joint;
• and
• a controller for eliminating a fundamental natural frequency of the object by controlling movement of the object based upon at least one of said joint torque and said position.

A manipulator comprising:

• at least one robotic member coupled to at least one joint;
• at least one joint control circuit, wherein said joint control circuit comprises:
• a position command unit issuing an instruction input in the form of a position command;
• a first summer circuit obtaining a difference between the instruction input and a position feedback signal measured at the joint to produce a position error signal;
• a second summer circuit obtaining a difference between an external joint torque disturbance of the manipulator and a joint torque measurement of said at least one robotic member to produce a joint torque error signal;
• a first controller, coupled to said first summer circuit, for receiving the position error signal produced by said first summer circuit, said first controller summing a derivative of the position error signal and the position error signal to produce a joint torque command;
• a second controller, coupled to said second summer circuit, receiving the joint torque error signal from said second summer circuit and producing a motor torque error signal;
• and
• a motor with a gearbox, coupled to said second controller, generating a joint position signal based on the motor torque error signal produced by said second controller.