This thesis aimed to eliminate tracking

error of traveling a circular profile on the CNC machine tools. Friction is one of the

most significant source of nonlinear disturbance for the motion control which caused

by the relative motion of different contact surface at the low velocity. The nonlinear

component of friction such as static friction (stiction) and the Coulomb friction should

be overcome so that the tracking error will be eliminated. When the X-Y tables are

tracking a circular profile, quadrant glitches appear at ninety degrees intervals, i.e. the

motion of one axis has a zero velocity crossing and reverses direction.-This thesis is aimed to eliminate tracking

error of traveling a circular profile on the CNC machine tools. Friction is one of the

most significant source of nonlinear disturbance for the motion control which caused

by the relative motion of different contact surface at the low velocity. The nonlinear

component of friction such as static friction (stiction) and the Coulomb friction should

be overcome so that the tracking error will be eliminated. When the X-Y tables are

tracking a circular profile, quadrant glitches appear at ninety degrees intervals, i.e. the

motion of one axis has a zero velocity crossing and reverses direction.