Abstract
This paper deals with the tracking control problem of a general class of nonholonomic dynamic systems with reference signals that may exponentially decay. By introducing a time-varying coordinate transformation and using the cascaded-design approach, smooth time-varying controllers are constructed, which render the tracking error dynamics globally -exponentially stable. The result shows that the persistent-excitation condition or not coverging to zero for reference signals is not necessary even for the globally
-exponential tracking of nonholonomic systems. The proposed method is applied to the tracking control of an underactuated surface vessel.
Acknowledgements
The authors would like to thank the National Natural Science Foundation of China for Distinguished Young Scholars (under the grant 60425308) and the Doctoral Research Foundation of the Educational Ministry of China (under the grant 20040286004) for financial supports for this work.