Observer-Based Coordinated Control for Blended Braking System with Actuator Delay

The coordinated control of a blended braking system is always a difficult task. In particular, blended braking control becomes more challenging when the braking actuator has an input time-delay and some states of the braking system cannot be measured. In order to improve the tracking performance, a coordinated control system was designed based on the input time-delay and state observation for a blended braking system comprising a motor braking system and friction braking system. The coordinated control consists of three parts: Sliding mode control, a multi-input single-output observer, and time-delay estimation-based Smith Predictor control. The sliding mode control is used to calculate the total command braking torque according to the desired braking performance and vehicle states. The multi-input single-output observer is used to simultaneously estimate the input time-delay and output braking torque of the friction braking system. With time-delay estimation-based Smith Predictor control, the friction braking system is able to effectively track the command braking torque of the friction braking system. The tracking of command braking torque is realized through the coordinated control of the motor braking system and friction braking system. In order to validate the effectiveness of the proposed approach, numerical simulations on a quarter-vehicle braking model were performed.

Brake Characteristics and Cooling Methods – A Review

Braking system is important in any automobile. It is essential to decelerate the vehicle and stop it. Friction braking system is widely used system of braking. It makes use of frictional force to safely retard the vehicle. The temperature of the brake pad (stator) and disc (rotor) increases because of frictional force between them. Higher temperatures may lead to fading of brakes resulting in its failure. This paper briefly reviews published works on studying the wear and thermal characteristics of brake pads and on various available brake cooling methods. The microstructural changes in the brake pads are analyzed and reason for enhanced wear at higher temperatures is traced out. The various test results obtained using microscope (SEM), Friction assessment screening tests (FAST), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) are described in brief. A description of the available methods of enhancing the brake cooling and decreasing the wear rate is discussed. This work will be useful in planning further research in this important area of automotive field.

Modeling and Simulation of Electro-Hydraulic Compound Regenerative Braking Control Strategy for Electric Vehicle

This paper mainly discusses the dynamic distribution of regenerative braking system and conventional friction braking system of EV.In order to meet the requirements of vehicle braking stability and recycle the braking energy whenever possible, the paper proposes a control strategy which based on ECE regulation and I curve.Then the proposed control strategy is embedded into the simulation software ADVISOR.The result shows that the control strategy of regenerative braking the paper presented is better than ADVISOR’s own on braking energy recovery, and is especially suitable for frequent braking city conditions.

EXPERIMENTAL AND NUMERICAL STUDY OF THERMAL ANALYSIS OF HIGH-SPEED FRICTION BRAKING SYSTEM

Thermal analysis can be used as one of the basis for the friction pair material selection in high-speed friction braking system. In this study, the experimental results showed that surface temperature could be reduced by increasing the radius of the friction disk or thermal conductivity coefficient of disk material with stable braking; In the early stage of long braking, the temperature on the friction surface rises rapidly, but further braking does not lead to a significant rise in temperature; In the case of short braking, there is not enough time for the friction surface to reach the critical temperature, and the disk surface reaches the maximum temperature at the end of braking. During long braking, the dimensionless time capacity of the friction surface reaching the highest temperature is F0 ≈ 0.1F0s.