Dual control theoretic driver assistance - Dynamic characteristics of steering torque control based on linear quadratic regulator

Abstract

This paper proposes a driver assistance system with a dual control theoretic scheme, which tries to perform safety control of a vehicle as well as identification of the driver's cognitive state simultaneously. The dual control theoretic driver assistance algorithm uses steering torque control based on a linear quadratic regulator (LQR). A controller and mathematical models for the vehicle and steering system were built, where the steering torque control was applied to switching feedback gains in the LQR controller. This paper discusses the dynamic characteristics for steering torque control under constraints on the state and manipulated variables.

Driver Assistance System With a Dual Control Scheme: Effectiveness of Identifying Driver Drowsiness and Preventing Lane Departure Accidents

“…Both the driver's input torque ℎ and the system's assistance torque ( ) are applied to the steering wheel. The controller is designed using state feedback [46], where the state vector is composed of the yaw rate ̇, yaw angle , lateral velocity ̇, lateral displacement between the system's target position * and the lateral position , steering angle , and steering angle velocity ̇. The state vector is assumed to be measured or calculated using vehicle motion sensors.…”

“…The state vector is assumed to be measured or calculated using vehicle motion sensors. In addition, switching gains 1 and 2 are applied to the steering torque control [46], and the gain is switched according to the active stage of control (first or second). When ( ) becomes less than 1 s, the assistance system's target position * for the first-stage control is set as the judgment line, and the assistance system performs steering control so that the vehicle travels parallel to the lane markers at the judgment line.…”

“…Against this background, we have proposed a driver assistance system with a dual control scheme, which tries to perform the safety control of a vehicle as well as identification of the driver's state (e.g., states of low arousal and degradation of mental and physical functions) simultaneously [46]. The assistance system works in a situation-adaptive manner [12], and it takes into account the characteristics of sleepy drivers and the driving context.…”

“…In section II, a driver assistance algorithm with a dual control scheme is described. The design of the proposed assistance system that employs steering torque control based on a linear quadratic regulator is briefly presented based in [46]. In section III, a driving simulator experiment is described.…”

Effectiveness of a Dual Control Theoretic Driver Assistance for Attaining Safety and Identifying Driver State

“…Also, after 5 seconds from initiating the second-stage control, the system finishes the control. In addition, an optimum control was applied to determine the assistance torque, and feedback gains were designed to obtain good control performance through numerical simulations using a general two-wheel vehicle model (Saito et al, 2014).…”