Actively damped robot

A method of damping a multi-axis robot arm, the robot arm comprising a plurality of arm portions rotatably connected together, the robot arm configured to be rotated about a plurality of rotary axes, the method comprising:

• measuring, by one or more sensors, one or more parameters of the robot arm;
• and
• controlling, by a controller, based on sensor measurements taken by the one or more sensors, a damping system coupled to the robot arm thereby to control a resistive force applied to the robot arm by the damping system, wherein
• the one or more sensors comprise one or more sensors selected from the group of sensors consisting of:
• a vibration sensor located on the robot arm at or proximate to a rotary axis of the robot arm, the vibration sensor measuring a vibration of the robot arm;
• a strain gauge located on an arm portion remote from the rotary axes, the strain gauge measuring a strain in that arm portion;
• and
• a temperature sensor located on the robot arm at or proximate to a motor of the robot arm, the motor being configured to move the robot arm, the temperature sensor measuring a temperature at or proximate to the motor, and
• wherein the one or more sensors comprise all of the vibration sensor, the strain gauge, and the temperature sensor.

A method of machining a workpiece to produce an aerospace component, the method comprising:

• controlling a multi-axis robot arm to move an end effector of the robot into contact with the workpiece and to machine the workpiece, the robot arm comprising a plurality of arm portions rotatably connected together, the robot arm configured to be rotated about a plurality of rotary axes;
• during the machining of the workpiece, measuring, by one or more sensors, one or more parameters of the robot arm;
• and
• controlling, by a controller, using sensor measurements of the one or more sensors, a damping system coupled to the robot arm, thereby to control a resistive force applied to the robot arm by the damping system so as to actively damp vibration of the end effector during the machining of the workpiece,
• wherein the one or more sensors comprise one or more sensors selected from the group of sensors consisting of:
• a vibration sensor located on the robot arm at or proximate to a rotary axis of the robot arm, the vibration sensor measuring a vibration of the robot arm;
• a strain gauge located on an arm portion remote from the rotary axes, the strain gauge measuring a strain in that arm portion;
• and
• temperature sensors located on the robot arm at or proximate to a motor of the robot arm, the motor being configured to move the robot arm, the temperature sensor measuring a temperature at or proximate to the motor, and
• wherein the robot further comprises a plurality of motors operable to move the robot arm, the one or more sensors comprise a plurality of temperature sensors, and, for each motor, one or more of the temperature sensors are located at or proximate that motor.

A robotic system comprising:

• a multi-axis robot arm, the robot arm comprising a plurality of arm portions rotatably connected together, the robot arm configured to be rotated about a plurality of rotary axes;
• a plurality of motors operable to move the robot arm;
• one or more sensors located on the robot arm;
• a damping system configured to apply a resistive force to the robot arm, thereby to resist movement of the robot arm;
• and
• a controller coupled to the one or more sensors and the damping system, the controller being configured to:
• receive sensor measurements from the one or more sensors;
• and
• control, based on the received sensor measurements, the damping system thereby to control the resistive force applied by the damping system to the robot arm,
• wherein the one or more sensors comprise one or more sensors selected from the group of sensors consisting of:
• a vibration sensor located on the robot arm at or proximate to a rotary axis of the robot arm;
• a strain gauge located on an arm portion remote from the rotary axes;
• and
• a temperature sensor located on the robot arm at or proximate to a motor of the robot arm, the motor being configured to move the robot arm,
• wherein the robotic system further comprises a plurality of motors operable to move the robot arm, the one or more sensors comprise a plurality of temperature sensors, and, for each motor, one or more of the temperature sensors are located at or proximate that motor.