Energy Optimization of Lateral Motions for Autonomous Ground Vehicles With Four-Wheel Steering Control

Abstract

In this paper, a hierarchical optimal four-wheel steering (4WS) controller is proposed to enhance the energy saving for vehicle lateral motions. By the integration of the four-wheel vehicle dynamics, wheel dynamics, and tire model, the vehicle propulsion power consumption is derived with respect to the front and rear wheel steering angles as control inputs. In the high level of the proposed controller, an autonomous path following control is developed to provide virtual control inputs including the lateral forces and yaw moment via the dynamic sliding mode control design. In the low level, the high-level virtual control inputs are distributed to the front and rear steering angles, in which the energy optimization problem is solved. The objective function of the optimization problem aims to minimize the vehicle propulsion power consumption and virtual control tracking error. Furthermore, the requirements of the vehicle stability and the path following accuracy are considered in the constraints. Verified by CarSim® and MATLAB/Simulink® co-simulation, the proposed 4WS hierarchical energy optimization controller can successfully reduce the power loss for vehicle lateral motions.

On the Energy Efficiency Potential of Multi-Actuated Electric Vehicles

“…The front and rear active anti-roll moments are computed as: 𝑀 𝐴𝑅,𝐴𝑐𝑡,𝑓 = 𝑓𝑀 𝐴𝑅,𝐴𝑐𝑡,𝑇𝑜𝑡 (25) 𝑀 𝐴𝑅,𝐴𝑐𝑡,𝑟 = [1 − 𝑓]𝑀 𝐴𝑅,𝐴𝑐𝑡,𝑇𝑜𝑡 (26) where 𝑓 is the front-to-total anti-roll moment distribution coefficient. The corresponding equivalent vertical force contributions at the wheel center are given by:…”

“…Most of the RWS studies do not include any energy consideration. Exceptions are [25] and [26], which, however, focus on specific transient maneuvers, rather than the RWS power consumption reduction potential. In [27], dynamic programming minimizes the cornering resistance in step steer and sine-with-dwell tests, via front and rear steering as well as camber angle control.…”

Contributions of vehicle dynamics to the energy efficient operation of road and rail vehicles

“…Wang et al [21] have proposed a four-wheel steering control to minimise the propulsion power consumption, while at the same time minimising the tracking error and improving vehicle stability. They concluded that for their chosen S-shaped manoeuvre, with a speed of 100 km/h, the propulsion power consumption was reduced by 17%.…”