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This paper presents an adaptation method of equivalent factor in equivalent consumption minimization strategy (ECMS) of fuel cell hybrid electric vehicle (FCHEV) using hilly road information. Instantaneous optimization approach such as ECMS is one of real-time controllers. Furthermore, it is widely accepted that ECMS achieves near-optimum results with the selection of the appropriate equivalent factor. However, a lack of hilly road information no longer guarantees near-optimum results as well as charge-sustaining of ECMS under hilly road conditions. In this paper, first, an optimal control problem is formulated to derive ECMS analytical solution based on simplified models. Then, we proposed updating method of equivalent factor based on sensitivity analysis. The proposed method tries to mimic the globally optimal equivalent factor trajectory extracted from dynamic programming solutions.

Wheelbase preview control system that uses state and input estimator to reconstruct state and preview information is proposed. Conventional preview control systems use Kalman-Bucy filters of augmented system, which is composed of dynamics of a vehicle and a road profile for estimation scheme. Use of road model makes control performance sensitive to model errors that are inevitable in real applications. Compared with the conventional preview control systems, the proposed control system adopts a state and input estimator to estimate state and road input simultaneously. The state and input estimator does not require a road model, which makes it not robust to road model errors. However, the state and input estimator is sensitive to measurement noises, since it uses inverse dynamics of a system to estimate unknown inputs.

Vehicle stability control system can enhance the vehicle stability and handling in the emergency situations through the control of traction and braking forces at the individual wheels. Because this system needs to handle the nonlinear and complex vehicle dynamics, the controller is required to have the robustness and the simple structure for practical applications in order to achieve the desired performance. This paper proposes a new controller based on the multiple sliding mode control theory for vehicle stability control system to satisfy these requirements. The proposed controller for the lateral motion makes use of both the sideslip angle and the yaw rate. It brings the vehicle sideslip angle and the yaw rate close to the desired ones so that the vehicle dynamics becomes stable and the vehicle traces the desired course even in limit cornering.

Vehicle stability control system is a new idea which can enhance the vehicle stability and handling in the emergency situation. This system requires of the yaw rate, side slip angle, and road friction in order to control the traction force and the braking force at the individual wheels. This paper proposes an observer for vehicle stability control system. This observer consisted of the state observer for vehicle motion identification and the road condition estimator for the identification of the road friction coefficient. The state observer uses 2 degree-of-freedom bicycle model with the Dugoff tire and estimates the system variables based on the Kalman filter. The road condition estimator uses the same vehicle model and identifies the tire-road friction based on the recursive least square method. Both estimators make use of each other information.

Conventional steering system has a mechanical connection between the driver and the front tires of the vehicle, but in steer-by-wire system, there is no such a connection. Instead, actuators, positioned in the vehicle's front corners receive input from the control module and turn the front wheels accordingly. In steer-by-wire system, steering wheel is an important part that not only transfers driver's steering input to the controller but also provides a road feedback feeling to the driver's hand. Thus the reactive torque actuator, providing road feedback, plays an important role in steer-by-wire system. In conventional steer-by-wire-system, a motor was used as a reactive torque actuator. But using motor has some disadvantages such as an oscillatory feeling, and improper and potentially dangerous acceleration of the steering wheel by the motor when driver's hands are released from steering wheel abruptly.

An electric motor for regenerative braking in front-wheel-drive hybrid electric vehicle is only connected to the front axle, and mechanical friction braking can be independently applied on each of the 4 wheels. Excessive regenerative braking only at front wheels to improve fuel economy can cause under-steer and eventually vehicle instability. Nonlinear tire characteristic may cause this vehicle instability in severe cornering with hard braking. Therefore, cooperative braking control strategy has to be considered nonlinear tire characteristic for guaranteeing the vehicle stability while enhancing the braking energy recovery. This paper is to compare the performance of cooperative braking control strategy according to consider the influence of braking force on the lateral force. Carsim™ software is used to evaluate the performance of cooperative regenerative braking control regarding to the vehicle stability and regenerative braking efficiency.