Design of full electric power steering with enhanced performance over that of hydraulic power-assisted steering

Abstract

This paper presents a method of designing a full electrical power steering system to replace a hydraulic power-assisted steering system with improved performance and benefits including energy saving, improved steering 'feel', simpler construction and environmental gain. The designed performance of the electrical power steering system represented an ideal hydraulic power-assisted steering power boost curve which was mathematically modelled to provide the required control characteristic for the electrical power steering system, including variation in the perceived power assistance with the vehicle's forward speed. A full electrical power steering system provides all the torque necessary to steer the wheels, and the steering feel is artificially generated by an electric 'feedback' motor which provides resistance to the driver's input. The performance of the electrical power steering system described in this paper was enhanced by manipulating the reactive torque to the driver's input at the steering wheel so that it depended upon the driving conditions. Full-vehicle software models were generated using ADAMS/car software based on an actual car fitted with hydraulic power-assisted steering and full electrical power steering. The simulation results from both models were compared, and it is concluded that the steering performances of both systems were similar but the steering feel of the full electrical power steering system could be tuned to provide improved feedback to the driver in use. The performance of the full electrical power steering system could be further improved with the introduction of a controller to manipulate the steering feel during undesired conditions.

Electric Power Steering System Control Strategy Based on Robust H∞ Control for Electric Forklift

“…Compared with the traditional steering systems such as the mechanical steering system and the hydraulic steering system, the electric power steering system has the characteristics of high control flexibility, a simple structure, and high safety. Therefore, researches on the electric power steering systems for electric forklifts have important engineering significant applications [29][30][31].…”

Integration of Drive-by-Wire with Navigation Control for a Driverless Electric Race Car

“…Electronic control allows development of algorithms that provide capabilities such as keeping a vehicle inside a lane when there is no driver input to increase road safety [5]. While a full steer-by-wire system would reduce driver steering effort considerably legal concerns prevent a full steer-by-wire implementation [5], [6]. In the event of a failure, it is preferable that a mechanical link is still present, so that control of steering is still possible.…”

Investigation of a steering defect and its compensation using a steering-torque control strategy in an extreme driving situation

“…To calculate the steering torque, the relationship between the front-tyre resistance torque and the steering states of the vehicle is often investigated to obtain the steering resistance torque, and then the steering torque that is fed back to driver is obtained by subtracting the power assistance torque from the power steering system. 2,9–12 Reimpell et al 5 divided the resistance torque into four parts based on the forces acting on the steered wheels. Jang and Karnopp 10 obtained the steering torque on the basis of the feedback of the tyre forces using the model of the power steering system based on a six-degree-of-freedom vehicle model.…”