Research On Key Technologies Of Space Payload Distributed Capture And Lock System

Space distributed capture and lock is one of the key technologies for spacecraft to achieve payload on orbit operation.It has great application prospects in space station payload replacement,cargo spacecraft payload transportation and on orbit service,and is one of the research focuses of China and other aerospace countries in the future.Since the 1960 s,foreign research institutions have carried out a lot of research on space payload capture and lock technology and conducted on orbit verification.In the past decade,domestic research institutions have made some progress in capture and lock technology,but most of them focus on integral capture and lock system,and the research on distributed capture and lock technology with stronger adaptability and wider application is still in its infancy.At present,with the development of space on orbit operation tasks such as the construction of space station in China,the demand for distributed capture and lock technology with high rigidity,high reliability,expandability,modularity and repeatability is extremely urgent.The general design,analysis and verification method of distributed capture and lock system has become one of the research subjects to be solved in the space field.Therefore,this paper carries out the research of high rigidity layout design method,modular locking mechanism design,dynamic tolerance capability analysis method,collaborative capture strategy and ground test simulation method for the distributed locking system.Aiming at the problem of high rigidity layout design of the distributed locking system,using the principle of mechanical stability of plant roots for reference,the optimization guideline of the join point position of the capture and lock system is established.Based on the growth law of plant adventitious root and fibrous root,the optimization model of the number-position of main join points and the shape optimization model of the effective junction interface between capture and lock element and payload is established.The payload finite element model and three-dimensional spring support model are constructed to lay the foundation for the fundamental frequency analysis of the system.In order to maximize the basic frequency of the system,the parallel algorithm is used to select the optimal location of the join points,and the relationship between the number of secondary join points and the fundamental frequency of the system is discussed.The optimization results of the method are compared with those of the conventional method to verify the effectiveness of the method.Based on the general layout of the lock release system,the modular parameter design method of the capture and lock mechanism is studied.This paper analyzes the working process and boundary conditions of the capture and lock system,designs the layout of the capture and lock mechanism,and proposes a parametric design method of the capture and lock mechanism based on the analysis of the error field.Based on the error field of the capture frame at the bottom of the payload,the capture trajectory planning and configuration design of the active part are carried out,and the kinematic model of the capture and lock mechanism is constructed to lay the foundation for the optimization of the mechanism parameters.Based on the shape and location of the effective junction interface,the configuration design of the capture frame is conducted.In order to evaluate the tolerance capability of the capture and lock system accurately,a dynamic tolerance capability analysis method of the distributed capture and lock system is proposed based on the analysis of the cooperative effect of four capture and lock units.The dynamic model between the robotic arm-load combination and the capture and lock system is established,which lays the foundation for the capture determination of the boundary pose payload.Make the research on the key pose of payload,analyze the error pose of load,and establish the model of critical capture pose.The dynamic tolerance process analysis of the interaction between the capture and lock system and the payload in the capture process is carried out.The pose trajectory of the robotic arm-load combination in the capture process is predicted by the pose iteration method to judge the capture success or failure of the boundary pose payload.By checking whether the capture and lock system can capture the boundary pose payload,the dynamic tolerance ability of the system can be obtained.The capture speed mode and collaborative capture strategy of capture and lock system are studied.The impact dynamics model of the combination is established.Based on the tolerance ability and capture impact,the capture mode is selected.Combined with the structural and dynamic characteristics of the orthogonal distributed capture and lock system,the action matching of the diagonal double capture hook under the limit condition is carried out,and the collaborative capture strategy of the four capture hooks is obtained.The four capture hooks use the contact force feedback of the six dimensional force sensor at the end of the robotic arm to sense the contact position,which provides the basis for selecting the collaborative capture parameters.In order to verify the effectiveness and feasibility of the collaborative capture strategy,the tolerance capability analysis method and simulation software are used to capture the typical boundary pose loads synchronously and collaboratively.According to the optimized layout of the capture and lock system and the parameters of the capture and lock mechanism,the prototype of the orthogonal distributed capture and lock system and the ground capture experimental system of space payload are designed.The dynamic characteristics of the capture and lock system are analyzed and verified by the system vibration experiments.The accuracy of tolerance capability analysis method is verified by synchronous capture experiments of space payload ground capture experimental system and capture and lock system.Collaborative capture experiments are carried out to verify the effectiveness of the capture strategy in improving tolerance.