Human-in-the-loop evaluation of remote manipulator system active damping augmentation

Abstract

This paper describes the application of controls-structures integration technology to benefit the on-orbit performance of the Space Shuttle remote manipulator system. Called active damping augmentation, the goal is to reduce the vibration decay time of the remote manipulator system following normal payload maneuvers and operations. Simulation of active damping augmentation was conducted in a real-time human-in-the-loop simulation of the remote manipulator system with the objective of obtaining qualitative and quantitative measurements of operational performance improvements from astronaut operators. Sensing of vibratory motions was simulated using a three-axis accelerometer mounted at the end of the lower boom of the remote manipulator system. The sensed motions were used in a feedback control law to generate commands to the remote manipulator system joint servo mechanisms which reduced the unwanted oscillations. Active damping of the remote manipulator system with an attached 3990-lb payload was successfully demonstrated. Six astronaut operators examined the performance of an active damping augmentation control law following payload maneuvers and Shuttle thruster firings. Significant reductions in the dynamic response were observed and investigation of performance benefits with heavier attached payloads was recommended.