Design and Ground Verification of Space Station Manipulator Control Method for Orbital Replacement Unit Changeout

Table 1

Subtasks and corresponding control algorithms of the first two stages.

	Subtask	Control algorithm
1	The manipulator gets close to the old ORU on exposed platform	Open loop path planning
2	The manipulator approaches to the ORU adaptor	Close loop path planning
3	The manipulator end effector captures the adaptor completely	Impedance control
4	The end effector locks the adaptor	—
5	The old ORU connection mechanism unlocks	—
6	The manipulator pulls out the old ORU from the ORU store on exposed platform	Impedance control
7	The manipulator with the captured old ORU moves to the top of the ORU store in the airlock cabin	Open loop path planning
8	The manipulator with the captured old ORU approaches to the ORU store in the airlock cabin	Close loop path planning
9	The manipulator inserts the old ORU	Impedance control
10	The old ORU connection mechanism locks	—
11	The end effector unlocks the adaptor of the old ORU	—
12	The manipulator withdraws to the top of the old ORU adapter	Impedance control
13	The manipulator backs to the initial pose	Open loop path planning