Research And Implementation Of Ground Microgravity Simulation System Of Space Robotic Arm

With the progress of space exploration, research and application of spacerobotic arm continues increasing. Space robotic arm plays an important role at theestablishment and maintenance of space station, and satellite recovery. To guaranteethe reliability of space robotic arm’s orbital service, it is necessary to simulatemicrogravity condition on the ground like space, and conduct a series of related test.Therefore, according to the requirement of space robotic arm’s test on the ground,this article conducts the research of microgravity simulation system of space roboticarm and analyses simulation error. Furthermore, tests are lunched to verify thetheory of error analysis and microgravity simulation effect.Comparing advantages and disadvantages of all the microgravity simulationmethods, the scheme of micrograviy simulation system of space robotic arm isformulated, satisfying testing requirement. The system compesates the gravity ofspace robotic arm with air suspension and gravity banlancing structure. To verifythe feasibility of the system scheme, this article builds the system dynamic modeland analyses the gravity balancing effect through the simulation. In addition, thisarticle proposes the security and protection system scheme, builds the mathematicalmodel of the protection system, and analyses its performance parametres throughthe Simulink simulation.According to the scheme of the microgravity simulation system, the structureof the system is designed and the strength of the weak parts in the system is checkedthrough finite element analysis. The whole system consists of the elbow, wrist andshoulder gravity balancing structure, achieving microgravity simulation of therobotic arm. At the same time, to ensure accuracy and safety of the system, thisarticle designs the installation and adjustment methods of the microgravitysimulation system and analyses the force of the system. Then, the design of theprotection structure is completed.To improve the system accuracy, this article researches and analyses the factorswhich influence microgravity simulation, and proposes the methods to compensateerror. In the microgravity simulation system, the spring stiffness, gravity of thespring structure, the pulley radius, the distance of the quality centre of the roboticarm to the axis and other factors will influence microgravity simulation effect. Sothis article detailedly analyses the influence of the factors through theoretical study,and finally gets the error value caused by the factors. This article puts forward themethods to compensate error for the factors, improving the system accuracy. In addition, this article analyses the influence on the gravity balancing structure, whichis caused by structure error of the robotic arm.At last, a test is carried out to research and analyze the gravity balancingstructure using spring, which is adopted by the system. After accomplishing thedesign of the gravity balancing structure using spring and test methods, the testsystem is demarcated. The system finally achieves microgravity condition and goodgravity balancing result through the structure adjustment. Then, the test isconducted, and the influence on gravity balancing effect is analyzed throughcomparative test, which is caused by gravity of the spring structure, the pulleyradius and stability of spring stiffness. Through test, this article finally verifies thecorrectness of the error analysis theory and the compensation methods.