Design and control of semi-physical simulation device for tether dragging system

Abstract:

To remove space garbage effectively and simulate the recycle process of abandoned satellites in space, we conducted ground test assessments on dragging retractable device by means of semi-physical experimental technology to verify the performance of the dragging system. Semi-physical simulation is a technology that uses physical objects or a combination of physical models and mathematical models for simulation. Ground-based semi-physical simulation experiment can be a priori study for space tasks, which can greatly reduce the cost of space experiments and effectively guide the design and control of space tasks. First of all, the dynamics modeling of the dragging process of tethered satellite was carried out, the mission goal of the dragging process was clarified, and the mechanical composition of the semi-physical dragging system was established. Secondly, the full physical simulation unit was designed as a passive loading unit. The satellite mass was simulated by using an equivalent inertia turntable. Then, the simulation loading unit was designed by a semi-physical simulation method to simulate the dynamic states of the target under the dragging action of the tethering system. Finally, in view of the disturbance of tension measurement error in the actual test process, a control strategy based on model predictive control was designed. To accurately control the tension and tether length of the dragging process, the experiment adopted double closed-loop motor joint control and combined tension position dual motor simulation through model predictive control. Results show that the tension error accuracy of model predictive control was 5%, which verifies the effectiveness of the tether retracting control system on the dragging process.