The Control Method of Force Loading of Robot on Load Transfer Mechanism of Space Station

When the robot loading force on the load transfer mechanism of space station, there exist some problems caused by the deformation of the load transfer mechanism along the force direction after spreading, such as unstable robot force control system, insufficient load accuracy, and long settling time. To solve these problems, a strategy for adjusting the admittance controller parameters adaptively is proposed. Firstly, the relationship between force and position is established according to the admittance control theory. And a force tracking/force loading controller based on the rectangular coordinate system is initially designed. Then, the parameters of the load transfer mechanism model are identified based on the loading experiment data by the least square method, and the relationship between force and position of robot in specific workspace is established. Finally, the parameters of the admittance controller are adaptively adjusted to make the robot dynamics model approximately match with the dynamic model of the load transfer mechanism. The real-time spatial loading force imposed by the robot on the end of the load transfer mechanism after spreading is realized. The experiment shows that the tracking error of the robot relative to the load transfer mechanism is less than 0.1 mm, and the loading force error is less than 1%. The simulation results show that the robot meets the precision requirement and provides a real equivalent space load for the load transfer mechanism.