Research On Contour Tracking Control For Direct Drive X-Y Table

Taking the National Natural Science Fund Project (51175349) and the LiaoningNatural Science Fund Project (20102165) as the background, this dissertation researcheson the direct drive servo control system X-Y platform. For influences of nonlinear systemdynamic, uncertainties, and complex contour error model of curve trajectory for directdrive numerical control X-Y table servo system driven the equivalent errors methodapplicable for multi-axis nonlinear motion system is adopted to establish equivalent errorsmodel, by the use of position tracking controller and equivalent error model-based ascontour tracking controller for nonlinear curve contour path to ensure that the CNC X-Yplatform machining accuracy and robustness. Main research contents include the followingparts:In order to meet the high-precision positioning requirements of the single-axis directdrive servo system, and ensure that the system had fast transient response and good loaddisturbance rejection capability.A disturbance compensation method of position controllercombined with optimal parameter disturbance compensating controller was proposed. Theposition controller determined the transient response performance and the loadcompensator improved the ability of disturbance suppression. And by using the Parsevaltheorem, its parameters were obtained from an optimization technique that transformed theposition deviation of the performance index from time domain into the frequency domain,and then the Routh -Hurwitz two-dimensional array was calculated to obtain the optimalproportional-integral parameters.This characteristics of the algorithm has caused thecomputational process analytic and simplifiedFor the traditional contour error model is complex relatively, Based on the establishednonlinear equivalent error model including the equivalent contour error and tangentialerror that easily calculated and suitable for general curves of X-Y stable, the contourcontrol problem was converted to the stabilization of error dynamic system. Introduced theequivalent sliding mode control theory applied in error to control the equivalent errorsapproached zero for contour controller. In order to further enhance the effective control of the sliding mode contour controllerequivalent error variable, to weaken the chattering sliding mode control systemperformance, the ultra spiral sliding mode contour controller is designed.Then the slidingmode surface and its derivative approach zero in finite time. The effects of chattering anduncertainties are reduced and the equivalent errors approach zero. Simulation results showthat the designed control system of X-Y table has strong robustness and high contouraccuracy.Based on the Beijing Smart Motion Company LM22-26 series of direct-drive X-Ystage as the control object. For the equivalent sliding mode contour control and optimalparameter compensated position tracking control method and the supercoiled sliding modecontour control and optimal parameter compensated position tracking control methoddesigned to directly drive X-Y table contour control system to the standard conditions, thecomparison of experimental study of the moving sub-parameter changes,respectively.Circular contour tracking movement and four leaves contour tracking movement,acomparative analysis of the robust performance of the direct-drive X-Y stage and contourtracking control performance. Experimental results verify the validity of the theory of theproposed control strategy and simulation results.