Self-oscillating adaptive design of systems with dry friction and significant parameter uncertainty

Motion control systems with dry friction and high-order uncertain plants suffer from one or more limit cycles which can be predicted with describing function theory. In this paper quantitative design theory is presented to satisfy given frequency domain tolerances in these systems. The case of linear time-invariant (LTI) compensation is studied first. Then it is shown how, in those systems with a limit cycle, self-oscillating design with an adaptive loop (SOAL) can be used to reduce the LTI compensator bandwidth for a large class of problems.