关键词: 摩擦力模型, 数控机床, 自适应估计, 滑模控制, 自适应鲁棒控制

Abstract: For machine tools,the contour tracking performance could be degraded due to the change of friction force and inertia in feed drive system.LuGre friction model was modified,and an adaptive robust control method based on this modified model was proposed.The modified model defined the transient deviation of bristle deformation as state variable so that static friction and dynamic friction were presented in parallel form in the model.It simplified the implementation of adaptation on system parameters and made the online estimates reflect their realistic physical meanings.The controller was synthesized with adaptive estimation and compensation while transient performance was guaranteed.A nonlinear feedback control with two segmental coefficients was introduced to replace the constant sliding-mode band design when robust control was synthesized,and difficulties to balance between steady accuracy and chattering near slide-mode surface were avoided during tuning process.The implementation of the proposed controller with the modified model was validated with hardware-in-loop experiments.Experimental comparisons in regard to the tracking performance with an amplitude-change sinusoidal reference indicated that the quadrant glitches due to friction disturbance could be considerably suppressed by the proposed controller.

Key words: friction model, numerical-control machine, adaptive estimation, slide-mode control, adaptive robust control