A time-varying saturated synchronous formation controller for nonholonomic mobile robots

In this paper, a new saturated synchronous controller is proposed for multiple nonholonomic wheeled mobile robots to perform a time-varying formation task. Each robot is controlled to track its desired trajectory, while synchronized its motion with the two neighboring robots. A novel dynamic model of the wheeled mobile robot is derived based on Lagrange method. The Lagrange multipliers of the robot are determined based on the input torques and the robot's velocities. The dynamic model is divided into translational and rotational model. A saturated synchronous translational controller is proposed to guarantee the asymptotic stability of both position and synchronization errors. A rotational controller is developed such that each robot always oriented towards its desired position. A simulation results verified the efficiency of the proposed saturated synchronous controller in the formation tasks.