Dynamic Modeling And Characteristics Analysis Of X-Y Pointing Mechanism Based On Hardware In The Loop Simulation

Space pointing mechanism is the key component of space satellite system and plays an important role in data transmission and space docking.Because space pointing mechanism is affected by gravity release and clearance of kinematic pair,complex dynamic behavior of mechanism is produced.Therefore,this paper takes X-Y type space pointing mechanism as research object,establishes precise dynamic model,builds semi-physical simulation experimental platform and carries out experimental research.The specific research contents are as follows:First of all,considering the clearance of rotating pair of mechanism,a dynamic model with clearance mechanism and without transmission component is established based on Lagrange method and Newton Euler recurrence equation,and the correctness of the dynamics is verified by MATLAB numerical simulation.The working principle of harmonic reducer is analyzed.Considering torsional rigidity and non-linear friction during transmission of harmonic reducer,the transmission dynamic model of X-Y type space pointing mechanism is established and the precise dynamics model of X-Y type space pointing mechanism is obtained.Secondly,for the purpose of carrying out experimental research on the precise dynamic model of X-Y type space pointing mechanism,the test platform is developed by semiphysical simulation technology,the structure design of the test platform is carried out,the control strategy of the test platform is formulated,and the control system is developed based on Lab VIEW to realize the control of the semi-physical simulation test platform.Then,torsional stiffness test and friction test under gravity and microgravity are carried out on semi-physical simulation test platform.To identify stiffness model by least squares method and nonlinear friction model of harmonic drive,an integrated algorithm is put forward to identify dynamic parameters in friction model and obtain accurate dynamic expression of X-Y type space pointing mechanism.Dynamic characteristics of X-Y type space pointing mechanism are simulated and analyzed under gravity and microgravity.Finally,based on the simulation analysis results,the precise dynamic model of X-Y type space pointing mechanism was studied,and the mapping relationship between the ground and space mechanism output torque was established for experimental research.Path planning of space-oriented mechanism output end is carried out.Semi-physical simulation test platform is used to study the law of mechanism output torque considering no-load and loading under gravity and microgravity,and to compare and analyze the law with that obtained by mechanism output torque mapping model.