Seibum B. Choi

In this paper, a new type of antilock brake system (ABS) algorithm is developed. A full-time feedback control algorithm differentiates the new ABS from rule-based conventional ABS algorithms. The rear wheels are controlled to create limit cycles around the peak friction slip points. From the cycling patterns of the rear wheels, the optimal slips are defined. The front wheels are controlled to track the optimal slips defined by monitoring the behaviors of the rear wheels. The new algorithm can be

An adaptive, sliding control algorithm is developed for automated throttle control of an I.C. engine to be used in drive-by-wire applications such as coordinated engine/transmission gear shiftings, traction control and autonomous vehicle control (IVHS). The paper presents a new sliding control formulation that includes combustion transport delays and a simplified adapation law to account for slowly varying engine parameters. The new technique is evaluated by computer simulation and laboratory dy

This paper summarizes data fusion, controller design and experimental work done recently for the longitudinal control of a platoon of autonomous vehicles. This paper presents alternative sub-models of an engine and a transmission to achieve the goal of precise spacing control with smooth ride quality. Adaptive observers are developed to estimate the vehicle-to-vehicle spacing and the closing rate. The estimated values are used in a sliding mode based controller. The developed control strategies

This paper presents a control architecture that simultaneously utilizes active front steering (AFS) and differential braking for vehicle lateral stability while minimizing longitudinal perturbations. This control scheme is based on the model predictive control (MPC) using the extended bicycle model that captures the lagged characteristics of tire forces and actuators. The nonlinearities of tire force are also reflected on the extended bicycle model by linearizing the tire forces at the operating

The electromechanical brake (EMB) is expected to be utilized for future brake systems due to its many advantages. In this paper, keeping commercialization of the EMB in mind, a new EMB clamping force controller is proposed to overcome the limitations of the existing controller, namely, the extra cost for sensor installation and response delay. To design the controller, both mechanical parts and electrical parts in the EMB have to be mathematically analyzed. Also, dynamic models, clamping force,

<div class="htmlview paragraph">This paper summarizes the design of a throttle and brake combined controller and experimental work done for the longitudinal control of autonomous vehicles. This paper presents a sliding mode based longitudinal control law, brake system sub-model, brake control law and a throttle/brake switching algorithm. The developed control strategies were implemented on a test vehicle and the longitudinal combined controls tested with a single vehicle using a predetermi

In this paper, a novel rollover prevention control algorithm is developed for application on vehicles with a high centre of gravity. The developed algorithm can be implemented on any vehicle equipped with an electronic stability program with or without an extra roll rate sensor. The vehicle rollover index is defined from the vehicle lateral kinetic energy and the new concept of virtual gravity. The algorithm is implemented on a production hydraulic control unit and tested using a typical medium

An adaptive control law and a distance rate observer were developed for the lateral control of autonomous vehicles. The control law and the observer were implemented on a passenger vehicle. The test results show that both tight lateral tracking control and smooth steering can be achieved without feed forward information. The developed control law is shown to be very robust to changes in the most critical vehicle control parameters.

Emission control is a very important issue in automotive engineering. In the urban trafic mode, the engine is known to be operated mostly in a transient state and the wide operating range and the inherent nonlinearities of the induction process make the design of the fuel-injection controller very difficult. In this paper, an observer-based nonlinear automotive fuel-injection controller is designed. The designed controller achieves excellent transient properties with a small chattering amplitude