Space Electrodynamic Tether Deployment Control Technology And Mechanism Design

Electrodynamic tether is an innovative space propulsion technology,which has broad application prospects in orbit maneuvering,spacecraft protection,abandoned satellite off-track and so on.However,even the most simple form of tethered satellite system,the dynamics and control problems are complex.As the tether has a small damping,flexible features,it is very easy to produce a series of complex movements and vibration when it is placed in the space environment and couples with satellites.During release and recovery of the tethered satellites,the change in tether length causes Coriolis acceleration,which may result in a significant wobble and vibration of the tether.Without control,the dynamic stress amplitude within the tether may exceed the strength limit of the material,resulting in system failure.In this dissertation,the key issue of the separation of space rope system is considered,and its dynamics and control are studied.The main contents are as follows:Based on the dynamics and control problems of the electrodynamic tethered system,the dynamical problems and the theoretical knowledge of the deployment of the tethered system under the continuous force control are studied.Combining the essence of the discrete control and continuous control,analyzing and finding the link during the deployment process of tethered system.Aiming at the problem of non-overshooting release and positive velocity constraint during the deployment of space tethered satellites,an ideal trajectory based on feedback linearization and backstepping is designed by theoretical analysis.Using a suitable controller to control the tether to track the ideal trajectory and simulation is done.Proposing a new Pulse-Width and Pulse-Frequency modulation control law with input limitation and apply it to the simulation of tethered satellites deployment trajectory-tracking.The simulation results show its performance with non-overshooting deployment,meanwhile,the positive deployment velocity can also be guaranteed simultaneously.It validates the effectiveness of distributed control method,which could be a reference for future space tethered satellites deployment system design.Designing a release mechanism based on electrodynamic tether satellites.Building three degree of freedoms ground satellite simulators and study the software and hardware design and related technology,which includes several subsystems of the simulation platform and infrared navigation system.