This paper describes a driving control algorithm based on a skid steering for a robotic vehicle with articulated suspension (RVAS). The RVAS is a kind of unmanned ground vehicle based on a skid steering using an independent in-wheel drive at each wheel. The driving control algorithm consists of four parts: a speed controller for following a desired speed, a lateral motion controller that computes a yaw moment input to track a desired yaw rate or a desired trajectory according to the control mode, a longitudinal tyre force distribution algorithm that determines an optimal desired longitudinal tyre force, and a wheel torque controller that determines a wheel torque command at each wheel in order to keep the slip ratio at each wheel below a limit value as well as to track the desired tyre force. Longitudinal and vertical tyre force estimators are required for the optimal tyre force distribution and wheel slip control. A dynamic model of the RVAS for simulation study is developed and validated using the vehicle test data. Simulation and vehicle tests are conducted in order to evaluate the proposed driving controller. It is found from simulation and vehicle test results that the proposed driving controller provides a satisfactory motion control performance according to the control mode.
This paper describes an optimal traction, braking and steering coordination to improve vehicle lateral stability and manoeuvrability of a six-wheel driving/six-wheel steering (6WD/6WS) vehicle. The optimal coordination controller consists of an upper and lower level controller. The upper level controller determines front, middle steering angle, desired net yaw moment, and longitudinal net force according to the reference velocity and steering angle corresponding to a manual driver. The desired yaw moment is calculated by sliding-mode control theory. Based on the desired longitudinal net force, yaw moment, and tyre force information as inputs from the upper level controller, the lower level controller determines distributed lateral tyre forces and longitudinal tyre force on each wheel in proportion to the size of the friction circle of each wheel. The size of a friction circle is estimated using longitudinal/lateral velocity, yaw rate, wheel torque, and wheel angular velocity. Vehicle–driver–controller closed-loop simulations have been conducted to investigate the improved performance of the proposed optimal coordination controller over a conventional direct yaw moment controller (DYC) of the vehicle equipped with a mechanical drive system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.