Motion Error And Reliability Analysis Of Space Cell Robots

With the rapid development of the aerospace industry,the magnitude of future space missions has increased sharply.Complex and unpredictable space mission scenarios have placed higher demands on the reliability of space control devices.The space cell robot is a new type of space control mechanism with a high degree of autonomy and environmental adaptability,which is expected to meet the needs of future diversified space missions.In order to enable space cell robots to better complete complex space tasks,it is of great practical significance to conduct in-depth studies on their reliability issues.This paper analyzes the reliability of space cell robots from quantitative and qualitative perspectives.In terms of quantitative analysis,the sources of robot errors are clarified,mainly including the following four aspects: manufacturing and assembly errors of the central axis of the bevel gear,errors of the joint servo positioning device,errors of the face gear transmission mechanism,and other factors such as temperature and force Error.On this basis,the five-parameter model of the mechanism was established,the pose matrix of the end effector was solved using the positive kinematics equation,and the error calculation model of the single joint cell and the error calculation model of the space cell robot were established by the differential method.According to the error calculation model of the space cell robot,for any given task determined by the space cell robot,based on the inverse kinematics and Monte Carlo method,the movement reliability calculation model of the space cell robot is established.In terms of qualitative analysis,the space cell robot is divided into agreed levels,and the functional and structural levels of joint cells and interstitial cells are drawn.By analyzing all possible failure modes in the robot system,the impact caused by each failure mode and the severity level of the impact,the system is analyzed by FMEA.Based on the hazard matrix method,the ranking of the magnitude of the impact of each failure mode on the robot is obtained.Draw a fault tree where the joint cells and interstitial cells work abnormally.Based on the downward method,there are 9 minimum cut sets for the joint cell fault tree and 19 minimum cut sets for the interstitial cell fault tree.The Monte Carlo method is used to simulate the failure distribution of each component in the joint tree and interstitial cell fault tree,and calculate the probability importance and mode importance of each component.When the joint cells in the robot system are performing swinging or rotating tasks,the components that affect the reliability of the joint cells are mainly connected to the female head,the battery module,and the digital steering gear.When the interstitial cells in the robot system are performing the task of finding the next target cell,the main components that affect the reliability of the interstitial cells are the main control board,the chassis bracket,the driving wheels,and the digital steering gear.Through the above analysis work,the high-risk failure mode and weak parts of the space cell robot are obtained,which provides a certain reference for the improvement and reliability improvement of the space cell robot system.