Time-varying formation control for nonholonomic wheeled mobile robots via synchronization

In this paper, a new synchronous control law is proposed for multiple nonholonomic wheeled mobile robots (WMR) to perform a time-varying formation task. Each robot is controlled to track its desired trajectory, while synchronized its motion with the two adjoining robots. A novel dynamic model of the WMR is derived based on Lagrange method. The Lagrange multiplier of the WMR is determined based on the input torques and the robot´s velocities. The dynamic model has been divided into translational and rotational model. A synchronous translational controller is proposed to guarantee the asymptotic stability of both position and synchronization errors. A rotational controller is designed such that the robot always facing its desired position. A simulation results verified the effectiveness of the proposed synchronous controller in the formation tasks.