Experimental Verification of Reaction Torque Control Based on Driver Sensitivity to Active Front Steering

In today’s world, the effectiveness of electronic active control systems in stabilizing a vehicle’s motion has been recognized; thus, numerous active control systems have been developed to realize effective braking torque and traction control and have been incorporated in mass-produced vehicles. However, an effective active control system for steering is not yet available. Active front steering (AFS) is an effective technique to stabilize the motion control when methods such as the Direct Yaw Control (DYC) are used; however, for a vehicle, it is difficult to resolve the problem of interference between driver steering and automatic steering with AFS. Some studies have verified that AFS is effective from the viewpoint of vehicle motion physics but such verification alone is insufficient. Since the driver has control of the steering wheel, driver sensitivity interferes with vehicle motion control, and the theoretical effect of control by AFS cannot be realized. This problem is known as the steering interference problem. Therefore, it is important to ensure that the active steering control system does not interfere with driver steering. In this paper, we evaluate driver sensitivity quantitatively using a steering device, and we verify the efficacy of the reaction torque control method based on the fundamental characteristics of driver sensitivity.