Fixed-Time VFO Control Design for Nonholonomic Mobile Robots With Constrained Control Inputs

This article presents a fixed-time vector-field-orientation (VFO) control law for unicycle-like nonholonomic mobile robots. We consider a set-point control problem in the presence of control inputs constraints and task-execution time constraints. The control law is based on the VFO methodology, which is characterized by nonoscillatory and well-predictable time evolution of transient states for unicycle-like robots. A formal stability analysis for the closed-loop dynamics is provided based on Lyapunov theory, and moreover, a method for a priori estimation of the upper bounds of the convergence time, in the presence of control input constraints, is presented. Finally, the control performance is illustrated by results of numerical simulations and experimental tests.