Feedback Design of Closed Contour Servomechanisms

Two-dimensional (x, y) profile or curve tracers are considered in terms of position errors and peripheral velocity errors as the servomechanism follows a closed contour without introducing external forcing functions. The servo system is implemented using standard position controls with nonlinear cross-axis feedback terms, which are generated analytic functions of the pattern. Each axis essentially serves as a feedback path for the other axis in this system. Linearization enables one to design the system dynamics and test the controls. A machine tool using the nonlinear feedback system was constructed and tested. Performance was excellent, and an example of the results is presented.