Research On Motion Control Strategy Of Micro-low Gravity Robot Based On Fine/Coarse Positioning

With the development of the aerospace industry,my country has successively launched many satellites for space exploration.In order to ensure the normal on-orbit operation of satellites in space,it is necessary to design a ground air flotation platform for simulation experiments.Because of its large size,heavy weight,and expensive construction,designing lightweight space robots is an effective way to solve current problems.In addition,with the successful launch of my country’s space station,experiments such as the rendezvous and docking of simulated satellites,satellite formation flight and proximity operations,and satellite capture will be completed in the space station in the future.For the space robot,this paper takes the micro-low gravity robot as the research object,and studies the positioning and motion control system of the micro-low gravity robot.The main work consists of the following aspects:The realization method of the micro-low gravity environment simulation based on the principle of air flotation,the working principle of the underlying drive control system is discussed;the dynamic equations of the system under different coordinate systems are deduced according to the dynamic principle,and the measurement of Data preprocessing analysis method from inertial unit coordinate system to body coordinate system;according to the actual nozzle jet force direction,the decoupling distribution control strategy of nozzle thrust in thrust drive system is given.For the movement of the micro-low gravity robot in different working conditions,two positioning schemes of fine/coarse are proposed.The precise positioning scheme is based on the principle of multi-eye vision positioning,and the position and attitude information of the robot is measured in local modeling;the coarse positioning adopts the second-order approximate Picard algorithm to update the attitude angle,and the TWR algorithm is used to improve the UWB positioning accuracy and stability.A three-layer extended Kalman filter fusion algorithm is proposed to fuse the data of IMU and UWB,and the feasibility of the multi-sensor fusion scheme is verified by experiments.The cascade BP-PID motion and attitude control strategy of micro-low gravity robot is proposed.According to the BP neural network to adjust the PID parameters of the inner loop online,the robustness of the cascade PID algorithm is enhanced;the position-velocity double closed-loop system and the attitude control angular velocityangular acceleration closed-loop control system in the plane motion are proposed;based on the dynamics in Adams The model builds the simulation platform of the micro-low gravity robot,and builds a co-simulation system with Simulink to perform closed-loop simulation of the motion performance requirements under different working conditions,to verify the effectiveness of the proposed micro-low gravity robot motion and attitude control strategy and the sequence Robustness of the stage BP-PID control algorithm.According to the proposed multi-sensor fusion positioning strategy and motion control strategy,a software and hardware platform is built,and motion control experiments are carried out.For the hardware platform,build the hardware circuit of the underlying control system,such as the power distribution circuit of the system,the solenoid valve drive circuit for thrust distribution and solenoid valve opening,and the PCB of the system hardware;for the control system of the robot,implement cascade BP in the upper system-PID program,and apply push commands to the lower system;design the UWB main base station,sub-base station and tag subsystems respectively;Finally,through experiments on the proposed positioning and motion control algorithms,the reliability of the scheme is verified.