Abstract: Because of the shortages of traditional vehicle following systems,such as the big tracking errors occurred when the leader vehicle is accelerating or turning,an improved modeling algorithm of virtual flexible bar with force-delay function is proposed.A virtual force is introduced into the virtual flexible bar,therefore the trajectory of the follower vehicle can be accurately stuck to the shape of the virtual flexible bar which fits the leader's trajectory very well.The virtual force can be changed with the length and shape of the virtual flexible bar and come into action with a time-delay.MATLAB simulations and experiments on wheeled mobile robot have been carried out and the results show that the proposed algorithm has a better performance in trajectory tracking,and the trajectory error is obviously reduced compared with the algorithm without time-delay.