With a same Lyapunov function defined, the stability, robustness, and conve
rgence speed of three widely used trajectory-tracking control schemes, i.e.
, the proportional-derivative (PD) control, the PD control with a feedforwa
rd compensation, and the PD control with a calculated feedforward compensat
ion, are presented. All three control schemes are globally exponentially co
nvergent. The trajectory-tracking features of the three control schemes are
theoretically analyzed and compared. Suggestions are given for the choices
of the control parameters. (C) 2001 John Wiley & Sons, Inc.