Delay effects on the discontinuous stabilization of the nonholonomic integrator and its generalizations

Abstract

The nonholonomic integrator is a famous example in feedback design - although it is small-time locally controllable to the origin, no continuous feedback law exists. Therefore, any stabilizing feedback laws must be either time-varying or discontinuous. A previously studied discontinuous feedback law stabilizes initial conditions lying between two paraboloids and has a sliding mode on the $xy$-plane. We investigate the effect of introducing delays into this discontinuous feedback law. To a first-order analysis, the lag causes the sliding mode of the $xy$-plane to bifurcate into two switching regions where the resulting dynamics can be interpreted as a hybrid dynamical system with hysteresis. Counterintuitively, the presence of a delay can actually have a positive effect on both the size of the basin of attraction and the convergence rate of the controller. We also consider the natural generalization of the nonholonomic integrator to higher dimensions.