Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment  
[PERSON]  
1 School of Automobile and Transportation, Shenzhen Polytechnic, Shenzhen 518055, China;  
1 [EMAIL_ADDRESS] (J.W. ); [EMAIL_ADDRESS] (Z.D. ); [EMAIL_ADDRESS] (Z.L.) [PERSON]  
2 Science and Technology on Vacuum Technology and Physics Laboratory, Lanzhou Institute of Physics, Lanzhou 730000, China  
Different from general gear transmission, the space harmonic gear transmission has obvious non-linear characteristics. Although designers have considered many factors affecting the transmission performance and made necessary analytical simulation in the initial design stage, it is difficult to accurately calculate the influence of working environment (such as irradiation, atomic oxygen, microgravity, etc.) on the performance of the mechanism, which results in different degrees of deviation between the simulation results and the actual situation. The actual performance of space harmonic reducer in space will directly affect the normal operation of spacecraft. Therefore, it is necessary to carry out reasonable analysis, modeling, and detailed test research on transmission error, backlash, torsional stiffness, efficiency, and dynamic friction moment of the space harmonic gear transmission link, so as to accurately study and describe the transmission performance of the space harmonic gear transmission system. Few scholars have made relevant research on this issue. An accelerated life test of harmonic actuator was carried out in reference [7], and an accelerated life test of liquid lubrication in mechanical part of spacecraft was carried out in reference [8]. The lubrication performance of a strain wave transmission system in a space application was studied in [9; 10]. The transmission errors of harmonic drive gears were studied in [11; 12]. Torsional vibration caused by insufficient stiffness in the actuator of servo actuator, such as torsional vibration at the joint of robot in reference [13]. Robust speed control was proposed in [14; 15] to suppress the vibration caused by angle transmission error of planetary gear mechanism. The modeling and compensation method of the angular transmission error of harmonic driver were studied by [PERSON] et al. in [16; 17; 18; 19]. Similar to this paper, reference [20] designed a special test equipment for harmonic reducer, which carried out life evaluation tests for harmonic reducer of different grease lubrication in vacuum high temperature (90 \({}^{\circ}\)C), and tested the transmission efficiency of a harmonic reducer at different stages. The results show that the transmission efficiency decreases with the operation of harmonic reducer, and the test is terminated when the transmission efficiency decreases to 40%. Obviously, due to the friction face lubricant consumption and friction pair surface wear, resulting in the transmission efficiency with the test process in a downward trend. The results also show that MAC grease lubrication is better than PFPE grease lubrication. In order to obtain the environmental test data of harmonic reducer, reference [21] conducted evaluation tests on solid lubrication and grease lubrication harmonic reducer in the vacuum high temperature (\(-\)150\(\div\)200 \({}^{\circ}\)C) environment. The transmission efficiency, stiffness and transmission accuracy were measured during the test, and the results show that the life of grease lubricated harmonic reducer is longer than that of solid lubricated harmonic reducer. The life of a harmonic reducer with large speed reduction ratio (1:160) is tested in [22]. The size of the rigid and flexible gear of the harmonic reducer is small, and the wear resistance is relatively low. After the nitriding treatment, the surface hardness of the gear surface is improved, and then coats with grease for lubrication to obtain a good effect. Aiming at the application demand of space low temperature, reference [23] developed a harmonic reducer for vacuum low temperature (\(-\)150 \({}^{\circ}\)C) environment.