Dynamics and Control of Manipulator-Supported EVA Operations

When an astronaut performs an extravehicular activity (EVA) task at the end of a long manipulator, the astronaut's movement will have an effect on the stability of the EVA-manipulator system and thus, the astronaut needs to understand the effect in order to properly deal with it for a good performance of the EVA job. In this paper, dynamics modeling of the EVA and manipulator system is studied. A joint control method for the manipulator was proposed to provide the robot with a capability to compensate the dynamic effect of the astronaut's movement, so that the EVA operation can be satisfactorily performed. A human-robot coupled EVA supporting system is modeled using the MSC ADAMS software. The model is used to simulate the dynamic interaction between the astronaut and the manipulator. A control method is designed and applied to reduce the disturbance of the EVA supporting system. The capability of the proposed control algorithm to ensure the astronaut's operational accuracy for EVA tasks is shown simulation results.