The Design And Friction Compensation Of Experimental Turntable

Turntable is test equipment with important strategy and economic value, and widely used in aerospace, navigation, aviation and other fields. Its property guarantees precision and performance of aircraft and guided weapon system. However, the presence of friction in servo system results in the steady-state error, crawls, and limits cycle oscillation, and seriously impact on improvement performance of turntable. Therefore, study on friction compensation method of test turntable possesses great significance on weakening or eliminating the friction influence in the servo system and the design of high-precision low-speed turntable. In this paper, a two-axis experiment turntable is taken as study object; overall design is carried out in terms of requirement details, special research is launched on how to implement friction compensate in control strategyFirstly, the mechanical part is determined on the basis of the overall program of experimental turntable. The use of horizon structure plus DC torque motor can achieve accurate non-blind tracking on moving targets at sea. To make friction compensation algorithm easier, an open control system is proposed and hardware and software parts are introduced respectively. Then uncertainty of the two-axis experimental turntable is calculated and analyzed in detail in order to prove if the design meets the technical requirements.Secondly, LuGre friction model is adopted to compensate friction link of turntable servo system in this paper. Simulations in MATLAB verify the description of LuGre model in frictional nonlinearity as pre-slide displacement and hysteresis. To get more precise static parameter and reduce coupling between static and dynamical parameters, partical swarm optimization algorithm based on simulated annealing is used in static parameter identification for LuGre model parameter by two-step identification method, dynamic parameters are discriminate on the basis of acquired static ones.And then, mathematical model is established based on the selected components. The study of the turntable servo system laid the foundation for the implementation of friction compensation. The PID compensation and the compensation method based on LuGre friction model are introduced in detail.Finally, the two adopted methods of friction compensation are simulated, and the advantages and disadvantages of these methods are compared. The results show that compared to ordinary PID, fixed compensation method based on LuGre friction model achieves better effect.