Study On The Dynamics And Control Of The Space Electromagnetic Docking

With the development of the small satellites, on-orbit servicing and counterspace technologies, the spacecraft autonomous rendezvous docking are emerging as important fields in space. The spacecraft rendezvous docking based on the traditional thruster come with several challenges such as propellant consuming, plume contaminations and docking impact, using electromagnets as actuation of spacecraft for rendezvous docking have some distinct advantages and favorable applications.This thesis investigates the dynamics and control of the electromagnetic docking system, and research works are focused on the electromagnetic docking basics, force/ torque models, nonliner control algorithms for simplified ground prototype and the measurement and validation system of electromagnetic docking concept. The main contributions of the thesis are as follows:Firstly, according to the electromagnetics theory, three different force/torque models of a single ring of current and the planar far-field model of multiple rings of current are built, which are used to study the nonlinear control of electromagnetic docking. The effect of earth's magnetic field on satellites with electromagnetic docking system is analyzed. The simulation resuts show the forces produced by the earth's magnetic field are negligible, but the torqueses produced by the earth's magnetic field should be considered.Secondly, using PID control and Sliding control methods, nonliner control algorithms for simplified electromagnetic docking ground prototype are designed and compared. The simulation results validate the efficiency of the control algorithms. Finally, the design and experiment of the measurement and validation system of the electromagnetic docking concept are described, the electromagnets are designed, and the further experiments are discussed.At present, the study on electromagnetic docking technology of spacecraft remains concept design, there are some of unsolved problems both in theory and engineering applications. This thesis presents some preliminary research results about the dynamics and control of electromagnetic docking, which lay the foundations for further research on the design and experiment of electromagnetic docking system.The further investigation will focused on the nonlinear control strategies for electromagnetic docking of on-orbit spacecraft and the ground demonstration technologies.