Research On Control Technology Of Transonic Manipulator Considering Nonlinearity Of Backlash

Backlash is a position error existing in transmission parts. As a kind of discontinuous nonlinear with dynamic, non-differentiable and non-smooth characteristics, it exists in the mechanical transmission system widely, and has a serious influence on the system dynamic performance and steady-state precision.there is always nonlinear backlash in the transmission mechanism of cartridge auto-loader. So it is necessary for a study of the backlash in the transmission system to improve the technical index of cartridge auto-loader and the dynamic performance of each component. This paper takes the cartridge manipulator as the research object in the cartridge auto-loader. The main research is the compensation control technique of backlash nonlinear in transmission system.An adaptive fuzzy sliding mode control(AFSMC) based on back-stepping method is proposed for the Rotary positioning system of cartridge manipulator with parametric variation and nonlinear backlash. Firstly, rotary transmission system is analyzed by the mechanism analysis method, and an approximate dead-zone function is introduced to build the kinetic model of cartridge manipulator with backlash. Then, by selecting the Lyapunov function through back-stepping approach, an AFSMC scheme is developed to compensate the influence of parametric variation and nonlinear backlash. And a fuzzy logic inference mechanism is utilized for implementing a hitting control law to avoid the chattering phenomenon on the traditional sliding mode control. Finally, compared with the PID control, simulations show that the AFSMC based on back-stepping method not only reduces gear transmitting torque oscillation significantly, but also has higher accuracy and robustness in performances.Due to higher requirements of the system hardware, it’s difficult to apply the AFSMC based on back-stepping method directly. Therefore, the idea of "equivalent disturbance" is introduced to simplify the kinetic model of cartridge manipulator by treating the parametric variation and nonlinear backlash as exterior disturbance. And an adaptive sliding mode control scheme based on disturbance observer is redesigned and applied to the actual cartridge manipulator system. From the experiment results, it can be observed that the proposed control scheme not only meets the positioning requirement precisely and quickly, but also has good robustness to the parametric variation.