Research On Modeling And Active Vibration Suppression Of Space Maglev Vibration Isolation System With Payloads Variation

Tiangong No.1 and No.2 space stations were completed in 2011 and 2016,and the China Space Station will be deployed in orbit in 2022.This is of great significance for promoting the high-quality development of our country's space environment exploration to a new level.As the key equipment for carrying precision loads,connecting to the space station,and canceling disturbances,the space active vibration suppression and isolation system is of great significance to the task of precision scientific experiments.In the space environment,human activities,attitude and orbit control adjustments,and mechanical reciprocating motion will produce broadband and small amplitude vibration disturbances.How to provide a quasi-static environment under multi-source vibration disturbance conditions for the payloads of different scientific experiments has become the key to the successful completion of the task of the space vibration suppression system.This dissertation takes the magnetic suspension active vibration isolation system in the space environment as the research object,establishes the kinematics and coupling dynamics model considering the influence of the experimental load replacement on the system,and derives the active decoupling and nonlinear redundant actuation coordination method.The effectiveness of the proposed method is verified by ground experimental system and corresponding means.Aiming at the problem that most of the existing vibration suppression systems are based on certain payload,this article focuses on variable payload conditions and carries out the analysis of the impact of their changes and redundant actuation coupling on the system.For the space maglev vibration isolation system,this thesis firstly establishes a six-Do F kinematics and dynamics model of the system considering payloads variation conditions in the special Euclidean group (3)space;then it introduces unified variables to describe the impact on the system kinematics and dynamics caused by payload variation.Through integration and analysis,a standardized model for the control system is derived,which provides a basic reference for state coupling and decoupling and advanced vibration suppression control.Furthermore,based on this model,a multi-source motion information estimation and measurement method using optical/inertial sensor arrays is proposed,and a motion state fusion and estimation strategy based on multi-source perception information is established to meet the key information acquisition requirements of the model in a special space environment,and lay the foundation for utilize.Based on the in-depth analysis of the coupling properties of the system,the coordination method of coupling active decoupling and nonlinear redundant drive are derived.When the vibration isolation system performs payload replacement according to task requirements,the known assumptions of the dynamic model are destroyed,and the resulting coupling of motion states will greatly reduce the vibration suppression effect of the vibration isolation system.In order to solve this problem,with the goal of improving the payload adaptability and system intelligence of the vibration isolation system in an unmanned environment in space,the reversibility analysis of the redundantly driven MIMO system is carried out,and the analytical decoupling and self-decoupling methods of state coupling based on the principle of inverse system are given..In order to solve the problems of internal force confrontation,uneven heat consumption,and energy loss introduced by non-affine redundant driving,the optimal coordination methods of their respective driving forces were deduced for two typical working conditions.Finally,by combining drive coordination with state decoupling,a decoupling mapping from controllable degrees of freedom to the actual motion state of the system is constructed.In order to provide a quasi-static environment for the experimental payload under the condition of multiple disturbance sources,an active vibration suppression control strategy based on multi-source information is proposed.The control target and evaluation index of the vibration suppression system are analyzed.Based on the multi-source information,a multi-target control model weighted by the frequency domain and an adaptive compensation model are constructed.The control law is optimized based on the objective.The feedback active vibration suppression control law that meets the multiobjective needs is designed,and the vibration transmission path adaptive feedforward compensation control law meets the contradictory vibration suppression and vibration suppression in different frequency domains.Track control requirements.By combining with the aforementioned state perception,nonlinear driving force coordination and motion state decoupling,an active vibration isolation controller for the six-Do F maglev vibration isolation system is constructed.Based on a mechanical frame of the existing maglev vibration isolation platform,a prototype of the maglev vibration isolation system with high-precision acquisition,drive system and strong real-time control system was developed,as well as the ground limited degree of freedom and zero gravity simulation auxiliary device.The prototype assisted by this device can simultaneously simulate three-degree-of-freedom zero-gravity working conditions on the ground.Compared with the falling tower method,it effectively reduces the complexity of the low-gravity ground test and improves the convenience of the ground test.Based on this prototype,the corresponding ground environment experiments were carried out to verify the sensing and measurement strategies,active decoupling methods,nonlinear redundant driving force coordination methods and active vibration suppression strategies under multi-source disturbances proposed in the previous chapters.Corresponding simulation verification was carried out in the part lacking physical experimental verification conditions.A series of experimental results show the effectiveness of the aforementioned sensing,decoupling,coordination and control methods.The research results of this paper can be applied to the analysis,design,manufacture,and control of the space station's low-gravity vibration suppression and isolation system.It has certain theoretical guiding significance and engineering realization value for improving the effective utilization of the near-zero gravity environment of low-Earth orbit.