Design and Multi-Objective Performance Optimization of a Novel Steering Technology for Heavy Goods Vehicles

Abstract

A multi-objective optimization (MOO) approach is utilized to design a controller for a novel rear-steering technology named “Brake-Actuated Steering” (BAS). This system uses individually controlled brakes to generate differential longitudinal forces on each side of an axle, causing it to steer. Compared to other active rear-steering solutions utilizing path-following control, the BAS system is expected to provide comparable maneuverability performance, while offering approximately a 50% reduction in both mass and costs. Two objective criteria that define the performance and control effort of the BAS system are considered. Constraints are imposed limiting the feasible set of design variables to ensure stability of the controller, and sufficient centering capability of the steering system in emergency braking conditions. The optimization is performed for low-speed cornering of a tractor-semitrailer under various operating conditions, including low-friction surfaces, different axle loadings, and vehicle speeds. The optimization provides a set of Pareto-optimal fronts, minimizing the objectives. Simulations are used to compare the performance of a nonoptimal design for the BAS axle prototype to that of the optimized axle design. These validate the superior performance resulting from the optimization, with root mean square error of the steering angle and the energy consumed by the towing unit reduced by 48% and 21%, respectively. Model and controller validation and the performance of the system are verified by experiments on a prototype vehicle system.