Robust H∞ Output-Feedback Yaw Control for Vehicles with Differential Steering

Abstract

This paper examines the problem of designing a robust H∞ output-feedback yaw controller with both input and output constraints for four-wheel independently driven in-wheel electric vehicles (EVs) with differential steering. Specifically, the controller aims are to ensure the stability and improve the performance of the EV despite variations in the road adhesion coefficient, longitudinal velocity, and external disturbance. Based on the linear matrix inequalities approach, sufficient conditions for the existence of an H∞ output-feedback controller for linear systems with polytopic uncertainties, and input and control output constraints, are derived. Then those sufficient conditions are utilized to design an H∞ output-feedback yaw controller that guarantees the robust performance and stability of an EV over a wider range of road conditions. Finally, the capability of the developed controller is simulated on a vehicle model with uncertain road conditions and longitudinal velocities.

Definition of the Layout for a New Facility to Test the Static and Dynamic Stability of Agricultural Vehicles Operating on Sloping Grounds

“…As acknowledged in literature, the CoG position affects the operation of any active-safety device acting on several on-board technical systems [16,[28][29][30][31]. Every passive-or active-safety controller (or, generally, every control strategy to correct or optimize the trajectory of a vehicle) is based on the knowledge of the CoG position to infer the vehicle dynamic behavior and perform trajectory optimization for given initial conditions [32][33][34]. In addition, the capability of leveraging the CoG position could be the starting point to redesign or modify a tractor by varying its wheelbase, track width, front-axle mounting point or other design parameters [3,35].…”

“…For example, several scholars [1,5,36,37] use an analytical-Newtonian approach combined with a kineto-static approach based on rigid bodies. In some cases, these simulators have allowed to simulate the dynamics of a vehicle also in terms of response to an external disturbance: therefore, they have been used to investigate the robustness and fine-tune the characteristics of the software controllers that could be installed on such vehicles [32][33][34]. • Practical-experimental [22,40,41]: Using a dedicated test-facility, by following, developing or refining the test methods/procedures described by the legislation in force, e.g., ISO 789-6 [42], ISO 16231-2 [43], SAE J2141 [44], and SAE J2926 [45].…”

Robust H∞ Takagi–Sugeno fuzzy output-feedback control for differential speed steering vehicles

“…Note that the solutions for other indices, ρ = 1 , 2 , 3 , produce feasible solutions to the LMI constraints but leads to conservative controller parameter. It is important to mention here that without including the information of the time-derivative term as in equation (36), the LMI conditions would be infeasible when the FWIDEV is modelled at a single operating condition, such as using a 2-degree-of-freedom (DOF) equation as described in the paper by Oke et al 39 This is indicative of the control design approach used in this paper. For the purpose of comparison, the approach proposed in Oke et al 39 has been used to design a robust controller for EVs with polytopic uncertainties as presented in Table 3.…”

“…From the approach presented in Oke et al 39 and using Figure 1, the nonlinear equation of motion for the vehicle under consideration can be written as…”