Research On Ground Microgravity Experiment Device For Space Manipulator

With the development of space technology,more and more space equipments have entered space and become the basic configuration of space exploration.Space manipulator,as an important tool for human to explore the universe,is the embodiment of the development level of national science and technology.How to simulate the space microgravity environment on the ground is a necessary condition for the research of space manipulator,and it is also a key technical difficulty in space technology at present.In this paper,a ground microgravity experimental device is developed to simulate the space microgravity environment and the 6-DOF relative motion between the manipulator and the target load.The purpose is to complete the performance index measurement of space manipulator on the ground.The test and verification of the target load capture function of the space manipulator are carried out.Firstly,the overall design index of the experimental device is determined.After analyzing various gravity compensation schemes,a gravity compensation system based on active suspension method is designed to simulate the microgravity environment of the target load.Using the relative motion principle,the motion system of the manipulator is designed and completed,and the relative motion of the target load is realized.Finally,the six freedoms of the target load are realized.Degree motion simulation;Aluminum profile frame is selected to build the experimental device framework,which can absolutely withstand the load of related parts,and has good strength and stability.The driving control system of the experimental device is designed to realize the movement control of the target load and the space manipulator,and the pose adjustment of the target load.Secondly,the coordinate system of the experimental device,the target load and the space manipulator is established,and the coordinate transformation among them is realized;the kinematics analysis of the gravity compensation scheme is carried out,and the relationship between the motor rotation angle and the target load pose adjustment is obtained,which effectively guides the target load pose adjustment;the influence of friction on the accuracy of the experimental device is studied,and the main friction force is the friction force.Including the friction force at the fixed pulley and the friction force at the guide rail,and aiming at the adverse effects,the corresponding solutions are put forward to improve the accuracy requirements of the ground experimental device as far as possible.This paper introduces the fixed pulley mechanism,so it is necessary to analyze the influence of the fixed pulley on the experimental device,taking into account the influence of the fixed pulley diameter on the accuracy of the experimental device,and puts forward the corresponding measures to improve the poor performance.Influences,and based on the experimental device environment,the capturing conditions of the manipulator are analyzed.Finally,in order to verify the rationality of the mechanical structure and the reliability of the electrical system of the ground microgravity experimental device developed in this paper,relevant experimental studies have been carried out in the laboratory,including the performance experiment of the ground microgravity experimental device,the capture experiment of the manipulator to the target load and the safety experiment of the limit system.During the performance experiment of the experimental device,each limit position is measured;during the manipulator's operation experiment on the target load,the electrical control signal of the experimental device can be transmitted in time,the electrical control system and the mechanical system can work together,and the manipulator can effectively grasp the target load according to the requirements,and successfully complete the expected operation function,which proves the design in this paper.Ground microgravity experimental device has reasonable structure and high reliability.Data acquisition,processing and analysis of the manipulator's motion are carried out,and corresponding curves are drawn.Through data comparison,the experimental results are in agreement with theoretical prediction,which proves that the ground microgravity experimental device developed in this paper can really achieve the desired goal.Experiments are carried out to verify whether the safety limit system has protection or not.The function of the experimental device proves that the limit system can protect the experimental device.