Research on High-Precision Attitude Control of Joint Actuator of Three-Axis Air-Bearing Test Bed

Abstract

Three-axis air-bearing test bed is important semiphysical simulation equipment for spacecraft, which can simulate spacecraft attitude control, rendezvous, and docking with high confidence. When the three-axis air-bearing table is maneuvering at a large angle, if it is only controlled by the flywheel, it will cause the problems of slow maneuvering speed and high energy consumption, and when the external interference torque becomes large, the control accuracy will decline. A combined actuator including flywheel, air-conditioner thruster, and automatic balancing device is designed, and a hierarchical saturation PD control algorithm is proposed to improve the control accuracy and anti-interference ability of the three-axis air-bearing test bed. Finally, the mathematical simulation of the proposed control algorithm is carried out, and the physical verification is carried out on the three-axis air-bearing test bed. The results show that the control algorithm has higher control accuracy than the traditional control algorithm, and the control accuracy is better than 0.1 ∘ and basically meets the attitude control requirements of the ground simulation in-orbit satellite.

Variable Structure Control and Its Ground Experimental Test for the Space Station Robot

“…To date, a variety of strategies have been published to compensate for the gravity of space robots for experimental tests on the ground. [6] emulates the zero-gravity environment for the space manipulator using an air-bearing platform, while the platform is mainly suitable for the planar mechanism whose motion is parallel to the air-bearing table [7]; A microgravity environment can also be created in a plane while in a free fall or a free-falling capsule at the microgravity center; however, the test time is too short, and available space for the robot is limited [8][9][10]; A microgravity test can be performed in the pool using neutral buoyancy. Nevertheless, the influence of fluid damping on test results cannot be negligible [11]; [12][13][14][15] emulate the process of capturing the space target by the free-floating robot mounted on satellites, using two industrial robots.…”

“…However, it is difficult to remove the influences of the test results caused by the coupled vibration of the serial multijoint space robot and suspension system. Unfortunately, building a simulated weightless test system for a large and heavy serial multijoint space station robot while choosing the most practical control algorithm from potential candidates is not a simple task and consumes a large amount of time, manpower, auxiliary facilities, and material resources [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”