Issues in Control and Monitoring of Intelligent Vehicles

by LI, LI.

Inspired by the recent developments, we studied some recent developments and research trends in intelligent vehicle sensing and control tasks. We emphasize on advanced vehicle motion control techniques and intelligent tires. The main research motivation is to improve drivers/passengers’ comfort and safety as well as highway capacity and efficiency. In Chapter 2, we presents a review of recent developments and research trends in vehicle lateral (steering) control tasks. It is an attempt to provide a bigger picture of the very diverse, detailed and highly multidisciplinary research in this area. Based on diversely selected research, this chapter explains the initiatives and techniques for vehicle lateral (steering) control with a specific emphasis on disturbance rejection, time delay, system dynamic variation tolerance and controller saturation handling. Besides, some other related topics including vehicle lateral motion sensory and observer (virtual sensor) design are also discussed. In Chapter 3, Lateral control of vehicles on automated highways often requires estimation of sideslip angle, yaw rate and lateral velocity, which are difficult to measure directly. Thus, several observers (virtual sensors) were developed in the last decade. To solve the unhandled estimation problem caused by dynamic model uncertainty, a robust observer using H design method is proposed in this chapter. It ? maintains the good disturbance rejection property that derived form previous research, 12 and simultaneously provides acceptable tolerance to model variance. Specially, effects of displacements of sensory, dynamics variance caused by mass/velocity/tire-road frictions change or nonlinear characteristic are studied. Simulations demonstrate the usefulness of the proposed observer. Being parallel to frequency domain robust steering controller designs, time domain robust steering controller designs attract continuous interest in the last decade. Based on previous research results, a systematic time design framework is proposed in Chapter 4. The design task is constructed as a multi-objective optimization problem which simultaneously considers system stabilization, disturbance rejection, actuator saturation and time delay. A mixed L / 1 H robust controller is finally obtained by ? solving a set of linear matrix equalities (LMI) that guarantee the performance requirements regarding these mentioned factors. Simulations show the effectiveness of the proposed design method. Cooperative driving technology with inter-vehicle communication attracts increasing intentions recently. It aims to improve driving safety and efficiency using appropriate motion scheduling of all the encountered vehicles. Under cooperative driving control, the motion of individual vehicles can be conducted in a safe, deterministic and smooth manner. This is particularly useful to heavy duty vehicles, since their acceleration/deceleration capacity is relatively low. Specifically in Chapter 5, cooperative driving at blind crossings (crossings without traffic lights) is studied. A concept of safety driving patterns is proposed to represent the collision free 13 movements of vehicles at crossings. The solution space of all allowable movement schedules is described by a spanning tree in terms of safety driving patterns; four trajectory planning algorithms are formulated to determine the driving plans with least execution times using schedule trees. The corresponding group communication strategy for inter- vehicle networks is also analyzed. Finally, simulation studies have been conducted and results demonstrate the potentiality and usefulness of the proposed algorithms for cooperative driving at blind crossings. Many tire fault monitors are designed nowadays because tire failure is proved to be one of the main causes of traffic accidences. However, most of them are high in manufacturing cost and unreliable. Thus Chapter 6 is devoted to solve this problem and a new practical tire fault observer is proposed. Based on the new introduced dynamic tire/road friction model that considers external disturbances, the observer estimate and track the changes of tire/road friction conditions using only vehicle track forces and wheel angular velocity information. Tire fault diagnosis is carried out as follows. Since the wheel speed sensor is one basic component of normal anti-lock brake system (ABS), the observer proposed could be easily realized in low cost within an anti-lock brake system. 14