Development of an Advanced Fuzzy Active Steering Controller and a Novel Method to Tune the Fuzzy Controller

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 multicriteria 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.

Development of an Integrated Control Strategy Consisting of an Advanced Torque Vectoring Controller and a Genetic Fuzzy Active Steering Controller

“…The GFASC developed in [13] has confirmed that superimposing the steering input provided by the driver with a correction generated by the active steering system is considered to be a continuous process, and is not perceived by the driver as being disruptive. It is also advantageous to employ steering intervention rather than braking or driving individual wheels when controlling the vehicle on slippery surfaces, since steering intervention requires less frictional force between the tire and the road to generate a corrective yaw moment.…”

“…Taking advantage of the strengths of each active chassis subsystem, the ideal traction and stability performance of the vehicle can be obtained by activating the subsystem or subsystems that will be most effective given the deviation between the desired and actual behavior of the vehicle. The performance and effectiveness of the advanced torque vectoring controller (ATVC) and the genetic fuzzy active steering controller (GFASC) were studied and evaluated individually in previous papers [12,13]. In this work, we investigate whether the integration of these stability control systems enhances the performance of the vehicle in terms of handling, stability, path-following, and longitudinal dynamics.…”

“…A comprehensive evaluation of the dynamic characteristics of a vehicle and the effectiveness of different chassis control systems can be achieved only when the results obtained from a variety of test maneuvers are combined and evaluated as a whole. Several test maneuvers have been used in the past to provide important information about different aspects of the dynamic behavior of the vehicle and the effectiveness of each individual chassis control system, namely the advanced slip control system [9], the advanced torque vectoring controller [12], and the genetic fuzzy active steering controller [13]. In this work, we use the same test maneuvers to evaluate the effectiveness of our integrated chassis control strategy.…”

“…The developed advanced torque vectoring controller consists of left-to-right and front-to-rear torque vectoring components, which work together to distribute the calculated corrective yaw moment in an integrated approach. Moreover, a genetic fuzzy active steering controller was developed using the AUTO21EV vehicle model [13], and the performance and effectiveness of this controller were studied using a driving simulator. In this work, we investigate whether the integration of these stability control systems enhances the performance of the vehicle in terms of handling, stability, path-following, and longitudinal dynamics.…”

“…where χ ATVC (δ corr ) is the ATVC activation function, which is defined as a function of the corrective steering angle (δ corr ); δ corr,max is the actuator range limit of the active steering controller, which is set to 3° [13]; and σ is the standard deviation, which is set to 0.7 in order to form the bell curve shown in Figure 5. Note that the shape of this activation function is designed such that the contribution of the ATVC is introduced gradually rather than abruptly.…”