Research On Switched Backstepping Control Method Of Two-mass Servo Drive System With Backlash

The mechanical backlash is a kind of strong non-differentiable nonlinearity,which is generally present in the servo drive system.It will cause mechanical oscillations,accelerate the degradation of mechanical parts,and generate mechanical noise in servo system.At the end of the backlash,impact can also occur due to mismatched speeds between the driven side and the drive side.If this strong nonlinearity is not suppressed,it will seriously affect the performance of the servo system.In order to solve this problem,this paper proposes a switched backstepping control strategy based on backstepping control theory and time optimal control theory.It is introduced the mathematical model of the permanent magnet synchronous motor in different coordinate systems,the mathematical model of the backlash,the mathematical model of the two-mass transmission system,and the fully closed-loop servo transmission system based on vector control in this paper.Secondly,the characteristics and effects of the backlash are analyzed,and a switched backstepping control strategy is studied for the oscillation problem caused by backlash.This strategy adopts different control methods in the backlash phase and gear engagement phase of the system.During gear meshing,a full closed-loop backstepping controller based on mathematical model is used.During backlash,a time-optimal controller based on time-optimal theory is used.In order to ensure the accurate execution of the switching action,the switcher is designed to accurately switch the two controllers.Finally,the correctness and effectiveness of the switched backstepping controller are verified on hardware experiment platform,with DSP+FPGA as the core chip.Experimental results show the proposed method can effectively suppress backlash nonlinearity and has good system performance.