INTRODUCTION Recently, electric vehicles (EVs) have attracted a great deal of interest as an elegant solution to environmental and energy concerns. Among other benefits, EVs are more efficient and can reduce or eliminate the environmental noise and pollutants that are associated with conventional internal combustion engine (ICE) vehicles considerably. Also, thanks to substantial improvements in electric motor and battery technologies, EVs now have driving performance metrics that are comparable to those of ICE vehicles. In addition, EVs are more appealing platforms on which to apply advanced motion control techniques, since the motor speed and torque can be generated and controlled almost instantly, and more accurately than any ICE or even hydraulic brake system. Figure 1 illustrates the AUTO21EV, which is a two- passenger, all-wheel-drive urban electric vehicle that has been developed and modeled in this work using the ADAMS/ View and MapleSim software packages. This vehicle has a configuration similar to that of the commercially-available Smart fortwo , but is equipped with four direct-drive in-wheel motors and an active steering system on the front axle. Table 1 lists some of the relevant parameters used in the AUTO21EV model. The use of small but powerful direct- drive in-wheel motors allows for the implementation of the most advanced all-wheel-drive system in which the optimaltraction force can be generated on all tires by controlling the tire slips at all times. Figure 1. AUTO21EV concept vehicle In 2004, BMW introduced its first commercial active steering system in its 5-series class of vehicles [ 1]. Active steering bridges the gap between conventional steering systems and steer-by-wire technologies. Although an active steering system allows for driver-independent steering intervention, the mechanical linkage between the steering wheel and the rack-and-pinion system on the front axle 2013-01-0688 Published 04/08/2013 Copyright © 2013 SAE International doi:10.4271/2013-01-0688 saepcelec.saejournals.org Development of an Advanced Fuzzy Active Steering Controller and a Novel Method to Tune the Fuzzy Controller Kiumars Jalali, Thomas Uchida, John McPhee and Steve Lambert Univ. of Waterloo ABSTRACT A two-passenger, all-wheel-drive urban electric vehicle (AUTO21EV) with four direct-drive in-wheel motors has been designed and developed at the University of Waterloo. An advanced genetic-fuzzy active steering controller is developed based on this vehicle platform. The rule base of the fuzzy controller is developed from expert knowledge, and a multi- criteria genetic algorithm is used to optimize the parameters of the fuzzy active steering controller. To evaluate the performance of this controller, a computational model of the AUTO21EV is driven through several standard test maneuvers using an advanced path-following driver model. As the final step in the evaluation process, the genetic-fuzzy active steering controller is implemented in a hardware- and operator-in-the-loop driving simulator to confirm its performance and effectiveness. CITATION: Jalali, K., Uchida, T., McPhee, J. and Lambert, S., "Development of an Advanced Fuzzy Active Steering Controller and a Novel Method to Tune the Fuzzy Controller," SAE Int. J. Passeng. Cars – Electron. Electr. Syst. 6(1):2013, doi:10.4271/2013-01-0688. ____________________________________ 241Downloaded from SAE International by University of British Columbia, Wednesday, August 01, 2018remains in place, acting as a fail-safe mechanism. An active steering system facilitates two major functions: realizing a variable steering ratio, and maintaining vehicle stability and maneuverability during emergency maneuvers or when driving conditions call for a change in steering response. Table 1. AUTO21EV model parameters The fundamental design conflict faced by conventional steering systems involves choosing a suitable geometric steering ratio, which affects not only the steering effort in the ma