Abstract: A nonlinear sliding mode controller is proposed to coordinate a group of nonholonomic mobile robots so that a desired formation can be achieved.By using sliding mode control approaches,we consider a two-vehicle team in leader-(follower) configuration that is required to follow a prescribed trajectory while maintaining a desired relative distance,relative bearing angle and heading orientation.Stability of the closed-loop system are studied using classical Lyapunov theory.We prove theoretically that under certain reasonable assumptions the formation is asymptotically stable even with bounded disturbances;that is,the proposed sliding mode controller can asymptotically stabilize the errors in relative distance,relative bearing and heading direction,respectively.Finally,a numerical simulation example is given for the two-robot case to verify the validity of our approach.