Coordinated contouring controller design for an industrial biaxial linear motor driven gantry

To improve overall contouring performance, it is no longer possible to neglect dynamic coupling phenomena that occur during contouring operations, especially for linear motor driven systems which often move at high speeds. This paper studies the high performance contouring control of a linear motors driven high-speed/acceleration industrial biaxial gantry. The gantry dynamics is first transformed into a task coordinate frame. A discontinuous projection based adaptive robust controller (ARC) which explicitly takes into account the dynamic coupling effect is then constructed to improve the contouring performance under both parametric uncertainties and uncertain nonlinearities. To reduce the effect of measurement noise, a desired compensation ARC (DCARC) scheme is also presented, in which the adaptive model compensation part depends on the desired contour and parameter estimates only. Comparative experimental results of the proposed algorithms along with a well tuned PID controller are obtained on a high-speed industrial biaxial gantry driven by linear motors. The results verify that both the proposed schemes outperform the PID controller and can achieve good contouring performance even in the presence of parametric uncertainties and uncertain disturbances, and the desired compensation ARC achieves the best contouring performance.