Trajectory-tracking control of an unmanned surface vehicle based on characteristic modelling approach:Implementation and field testing

In this study,a practical adaptive control scheme is proposed for the trajectory tracking of an unmanned surface vehicle via the characteristic modelling approach.Therefore,accurate tracking control can be achieved in the presence of unknown time‐varying model parameters and environmental disturbances.The control scheme comprises a trajectory guidance module based on the virtual target approach and a tracking control module designed by characteristic modelling theory.Firstly,the ideal control commands of the yaw speed and surge speed are generated using the position errors between the vehicle and the virtual target.Then,a second‐order characteristic model for the heading and surge speed channel is developed.The parameters of the model are updated by a real‐time parameter identification algorithm.Based on this model,an integrated adaptive control law is designed which consists of golden‐section control,feed‐forward control and integral control.Finally,the development processes of the vehicle platform and the control algorithms are described,and the results of simulation and field experiments are presented and discussed.

Trajectory-tracking controller for vehicles on inclined road based onUdwadia–Kalaba equation

Vehicle lateral control is an important subtask of vehicle autonomous driving.There are many external disturbances that will affect the lateral control accuracy of the vehicle,and the inclination of the road is one of the most important ones.The inclined road will lead to additional lateral forces on the vehicle and will also change the magnitude of support force on the vehicle.The change of lateral force and support force will ultimately affect the trajectory tracking performance of the vehicle.Most of the current trajectory tracking methods only consider the trajectory tracking problem on the plane.If the influence of the road surface is considered in the design of the vehicle's trajectory tracking controller,the dynamic response and the tracking accuracy of the vehicle can be improved.This paper proposes a method based on Udwadia–Kalaba equation to calculate the normal and lateral force on a vehicle tracking a desired trajectory on an inclined road.Further,a trajectory tracking controller that considers the road inclination is designed.Finally,the simulation of trajectory tracking performance with an inclination angle is carried out to verify the effectiveness of the proposed controller.