A novel nonlinear controller for enhancement of the transient dynamics performance of a three-wheeled vehicle during different conditions

In this study, a new controller to prevent the yaw instability and rollover of a three-wheeled vehicle has been proposed. This controller offers the most obvious opportunity for affecting the vehicle's lateral dynamics performance on the full range of nonlinearities during various operating boundaries. The active combined controller has been designed based on sliding mode control method using an active roll system and an active braking system to dominate the uncertainties of the nonlinear dynamic model. Firstly, to avoid rollover of the three-wheeled vehicle, the roll angle was considered as the control objective, and the anti-roll bar was employed as an actuator to produce the roll moment. Secondly, to increase the maneuverability and lateral dynamics enhancement, an active braking system was designed. In the control system, the yaw rate and the lateral velocity were regarded as the control variables to track their references. Moreover, to verify the performance of the mentioned combined controller, another control system has been designed using the linearization feedback control method. Then, computer simulation has been carried out with a 12 degrees of freedom dynamic model of the three-wheeled vehicle called the delta. Furthermore, a nonlinear tire model has been utilized to compute the longitudinal and the lateral forces. Next, the comparative simulation results confirmed the effectiveness of the robust control system to raise the vehicle's maneuverability and its rollover stability in comparison with the linearization feedback control method, especially when the three-wheeled vehicle is subjected to critical conditions.

Robust Vehicle Dynamics Control for a Sharp Curve With Uncertain Road Condition

Recently, more and more research has been conducted to develop Connected Autonomous Vehicles (CAVs) applications that ensures the safety driving of CAVs under some extreme situations. This brief presents a robust control strategy for CAVs to preserve a precise tracking performance and maintain the stability of lateral dynamics when passing a sharp curve with uncertain road friction coefficient changes. In the proposed robust lateral dynamics control, robust optimization-based lateral dynamics controller is designed to achieve the stability of the lateral dynamics with the consideration of the road friction coefficient uncertainty. Simulation validations are carried out to evaluate the proposed control strategy. The results show that the robust optimization-based lateral dynamics can improve the robustness even with the uncertainty of the road friction coefficient.

Global adaptive neural backstepping control of a flexible hypersonic vehicle with disturbance estimation

Purpose This paper aims to discuss the precise altitude and velocity tracking control of a hypersonic vehicle, a global adaptive neural backstepping controller was studied based on a disturbance observer (DOB). Design/methodology/approach The DOB combined with a radial basis function (RBF) neural network (NN) was used to estimate the disturbance terms that are generated by the flexible modes of the hypersonic vehicle system. A global adaptive neural method was introduced to approximate the unknown system dynamics, with robust control terms pulling the system transient states back into the neural approximation domain externally. Findings The globally uniformly ultimately bounded for all signals of a closed-loop system can be guaranteed by the proposed control algorithm. Additionally, the command filtered backstepping methods can avoid the explosion of the complexity problem caused by the backstepping design process. In addition, the effectiveness of the proposed controller can be verified by the simulation used in this study. Research limitations/implications Normally lateral dynamics issue should be discussed in the process of control system designed, the lateral dynamics are not included in the nonlinear dynamic model of hypersonic vehicle used in this paper, merely the longitudinal flight dynamics are discussed in this paper. Originality/value The flexible states in rigid modes are considered as the disturbance of the system, which is estimated by structuring DOB with NN approximations. The compensating tracking error and prediction error are used in the update law of RBF NN weight. The differential explosions complexity derived from the backstepping procedure is dealt with by using command filters.