• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.462-470
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• 1999

In this paper, we proposed a cross-couple controller for compensating nonlinear friction of the X-Y table of CNC machines. Due to the nonlinearity of the frictions, large contour errors, referred to as quadrant glitches, occur when each axis of the X-Y table makes a zero velocity crossing. To reduce the quadrant glitches the friction compensators and nonlinear friction observers for estimating Coulomb frictions are employed in the proposed method. A hyperbolic tangent function is used in reducing the magnitude of quadrant glitches and the CEM (Contour Error Model) is utilized for the estimation of the velocities. The performance of the proposed compensators is evaluated for several trajectories by computer simulations.