American Journal of Vehicle Design, 2014, Vol. 2, No. 1, 32-42 Available online at http://pubs.sciepub.com/ajvd/2/1/5 © Science and Education Publishing DOI:10.12691/ajvd-2-1-5 Modeling and Experimental Design Approach for Integration of Conventional Power Steering and a Steer- By-Wire System Based on Active Steering Angle Control Eid S. Mohamed 1,* , Saeed A. Albatlan 2 1 Automotive and Tractors Engineering Department, Faculty of Engineering, Helwan University, Mataria, Cairo, Egypt 2 Automotive Engineering Department, Higher Technological institute, 10 th Tenth of Ramadan city, 6 th of October Branch, Cairo, Egypt *Corresponding author: Eng_eid74@yahoo.com Received November 21, 2014; Revised December 05, 2014; Accepted December 07, 2014 Abstract With the continuous development of vehicle and electronic industry, Steering by Wire (SBW) is replacing the traditional steering device of vehicle. The SBW is reproducing realistic steering feel, improving the vehicle returnability and it reduces the oscillatory effect of the steering system when the vehicle passes through an uneven road. This paper aims to present an overview of the SBW with integrated hydraulic power steering (HPS) in commercial vehicle. The mathematical model has been used to evaluate the performance of SBW system by using Matlab/Simulink software package, a PID controller and Linear Quadratic Regulator (LQR) optimization techniques are employed to arrive at an optimal controller for the SBW to monitor the system dynamic behavior and stability characteristics. The test rig of SBW system showed a great benefit in modifying a conventional HPS system to be electronically SBW. Necessary sensors and actuators replaced the conventional steering wheel. A microprocessor and interfacing circuits are designed to active control of DC motor. Also a SBW should be considered as requirement for a DC motor actuator vehicle steer angle for operating at given desired reference value and a proper torque to boost undergoing for operating under different conditions. The steering response of practical tests depends upon uncertain quantities like front axle weight, damping and a varying friction condition. Experimental results of SBW show that high performance and robustness are achieved. Keywords: steering-by-wire, steering feeling, hydraulic power steering, steering torque, SBW dynamic model, a stability analysis of SBW, PID controller and LQR optimization techniques Cite This Article: Eid S. Mohamed, and Saeed A. Albatlan, “Modeling and Experimental Design Approach for Integration of Conventional Power Steering and a Steer-By-Wire System Based on Active Steering Angle Control.” American Journal of Vehicle Design, vol. 2, no. 1 (2014): 32-42. doi: 10.12691/ajvd-2-1-5. 1. Introduction Nowadays, a great development is occurring in the automotive systems due to the introduction of electronics, which act as an integrated part with the mechanical system. The result of this integration appeared as an improvement in all phases of automotive functions as: driving performance, fuel efficiency, exhaust purification, safety and comfort. Electronic Power Assisted Steering Systems (EPAS) and SBW are replacing hydraulic power steering in many new vehicles today [1]. Active front steering (AFS) system can realize steering intervention independent of the driver, optimize vehicle’s response to driver’s input and enhance the stability in emergencies by add an additional steering angle to the input of driver. In low-speed section, reduces steering gear ratios, in order to achieve steering lightweight and flexible requirements; In High speed section, increases the steering gear ratios, in order to enhance the high-speed steering stability. So far as safety and steering feelings are concerned, AFS is a main trend of the development of current steering system, the principle of AFS is add an additional angle to the steering wheel input by motor, so as to improve the stability, maneuverability and keep track ability [2,3]. An Electric Power Steering (EPS) system will be considered in this report. The modeling of this dynamic system will be achieved with both simplicity and usability taken into account. As such, a reduced-order model that reveals the important dynamic distinctions of the system will be developed from a more complex one. This model will be used to analyse various closed loop effects such as torque performance, disturbance rejection, noise rejection, road feel and stability. These fundamental effects (compromises) are used towards the design of a desired control system [4]. In [5] propose a new ideal characteristic curve that can be applied to the EPS. The characteristic curve should be straight when the steering angle is small. When the angle is larger than a special value, the quadratic curve, the tangent slope of which is larger than before, should be chosen, and this paper gives us the basic algorithm for the new characteristic curve.