Research On Multi-stage Damping Stabilization Strategy Of Combination After On-orbit Capture

With the deepening of human exploration of space,space missions have presented complex and diverse development trends.In order to avoid the high risk of astronauts' outboard operations,on-orbit service technology based on space robots is an important capability expansion for human space exploration activities.After the orbit capture,the mass characteristic parameters and the angular momentum distribution of the complex system composed of the end of the space robot and the target spacecraft are abrupt.The traditional hard-catch method maintains a constant position by the mechanical arm brake,and the angular momentum of the target spacecraft is directly transmitted to the base through the robot arm.If the angular momentum transmitted to the base exceeds the upper limit of the internal momentum exchange,it may cause instability of the complex system.The body system is unstable.Aiming at this problem,this thesis studies the multi-stage damping stabilization control strategy for spatial complex systems for on-orbit service tasks.The research content of this thesis comes from the National Natural Science Foundation of China(51875046).Details are as follows:Firstly,based on the Kane method,a dynamic equation of a floating complex with multi-stage controllable damping structure is established.Introducing a controllable damping unit composed of a damper and a damper at the joint of the space manipulator,the free floating regarded as an expansion of the base arm having six degrees of freedom,the target spacecraft is considered part of the last section of the boom.Kane method is used to analyze the dynamic mechanism of the composite and establish the dynamic equation.The effectiveness of the kinetic equation is verified by a joint simulation based on ADAMS and MATLAB software platform.Secondly,from the perspective of energy consumption and momentum transfer,the effectiveness of introducing multi-stage controllable damping device at the joint to maintain the stability of the composite system is studied.Based on the kinetic energy theorem,the buffer energy absorption principle of the soft capture model is analyzed.It converts the energy transmitted by the target spacecraft into heat energy to achieve energy dissipation.Based on the principle of conservation of angular momentum,the momentum equation of the complex system is established,and the angular momentum transfer mechanism in the complex system is analyzed.The migration of the angular momentum of the complex system after the space robot is captured in the rigid state and the flexible state is compared and analyzed under the software ADAMS.The conclusion is drawn that the damping coefficient of the controllable damping device at the joint can reduce the angular momentum transfer rate.Finally,a multi-stage damping stabilization control strategy based on differential evolution hybrid particle swarm optimization is proposed.Considering the coupling characteristics of the complex system,the objective function is designed with the maximum angular velocity of each joint and pedestal as the optimization target.Based on the differential evolution hybrid particle swarm optimization algorithm,the multi-stage damping global optimization of the complex is solved,and the dynamic equation and control algorithm are jointly solved.Obtaining the desired damping value,reducing the momentum transfer rate of the joint angle,so that the flywheel can absorb the full angular momentum transmitted to the base in real time.The simulation based on MATLAB software platform verifies the effectiveness of the control method.