Vehicle velocity optimization for ride comfort improvement of automated driving in speed hump conditions

Abstract

Abstract Speed humps are designed to slow down a vehicle to prevent potential accidents from happening. However, the speed humps deteriorate ride comfort significantly even if the driving condition is safe. By constructing an effective nonlinear full-vehicle dynamic model, this paper presents a novel velocity optimization method for automated driving vehicles to improve the ride comfort in speed hump conditions. Firstly, the dynamic analysis method of a full-vehicle model is introduced. In specific, the equivalent suspension and damping rates, which take the effects of the suspension mechanisms into consideration, are employed in a full-vehicle model. It is assumed that the future road profile is known. When a vehicle passes over a speed hump, the road disturbances are inputted into the wheels. The dynamic performances of a vehicle are described in terms of the vertical displacement and acceleration of the vehicle body. Based on the dynamic responses of a vehicle under different velocities, a multi-objective optimization function related to the vehicle velocity is derived for the least vertical displacement and acceleration of the vehicle body. Then, the optimal vehicle velocity is determined using Pareto optimality and the weighted sum method in the scope of the vehicle velocity. Finally, the sinusoidal speed hump is introduced to verify the proposed vehicle velocity optimization method for ride comfort improvement.