Jaeseung Cheon

Development of Brake System and Regenerative Braking Cooperative Control Algorithm for Automatic-Transmission-Based Hybrid Electric Vehicles

In this paper, a brake system for an automatic transmission(AT)-based hybrid electric vehicle (HEV) is developed, and a regenerative braking cooperative control algorithm is proposed, with consideration of the characteristics of the brake system. The brake system does not require a pedal simulator or a fail-safe device, because a hydraulic brake is equipped on the rear wheels, and an electronic wedge brake (EWB) is equipped on the front wheels of the vehicle. Dynamic models of the HEV equipped with the brake system developed in this study are obtained, and a performance simulator is developed. Furthermore, a regenerative braking cooperative control algorithm, which can increase the regenerative braking energy recovery, is suggested by considering the characteristics of the proposed hydraulic brake system. A simulation and a vehicle test show that the brake system and the regenerative braking cooperative control algorithm satisfy the demanded braking force by performing cooperative control between regenerative braking and friction braking. The regenerative braking cooperative control algorithm can increase energy recovery of the regenerative braking by increasing the gradient of the demanded braking force against the pedal stroke. The gradient of the demanded braking force needs to be determined with consideration of the drivers braking characteristics, regenerative braking energy, and the driving comfort.

A Study on In-wheel Motor Control to Improve Vehicle Stability Using Human-in-the-Loop Simulation

In this study, an integrated motor control algorithm for an in-wheel electric vehicle is suggested. It consists of slip control that controls the in-wheel motor torque using the road friction coefficient and slip ratio; yaw rate control that controls the in-wheel motor torque according to the road friction coefficient and the yaw rate error; and velocity control that controls the vehicle velocity by a weight factor based on the road friction coefficient and the yaw rate error. A co-simulator was developed, which combined the vehicle performance simulator based on MATLAB/Simulink and the vehicle model of CarSim. Based on the co-simulator, a human-in-the-loop simulation environment was constructed, in which a driver can directly control the steering wheel, the accelerator pedal, and the brake pedal in real time. The performance of the integrated motor control algorithm for the in-wheel electric vehicle was evaluated through human-in-the-loop simulations.

Development of a vehicle stability control algorithm using velocity and yaw rate for an in-wheel drive vehicle

This paper proposes a vehicle stability control algorithm that uses velocity and yaw rate during cornering for an in-wheel independent drive vehicle. The vehicle velocity control at the cornering determines the velocity limit that the vehicle can sustain the given cornering radius and controls the vehicle velocity for safe cornering if the vehicle velocity is faster than the velocity limit. The yaw rate control determines whether the vehicle is under steer or over steer during cornering and directly generates a yaw moment by independently driving and braking the in-wheel motor of each wheel. To evaluate the validity of the vehicle stability control algorithm, a co-simulator that integrated the CarSim vehicle model and MATLAB/Simulink controller model was developed.

Development of regenerative braking co-operative control system for automatic transmission-based hybrid electric vehicle using electronic wedge brake

This research proposes a regenerative braking co-operative control system for the automatic transmission (AT)-based hybrid electric vehicle (HEV). The brake system of the subject HEV consists of the regenerative braking and the electronic wedge brake (EWB) friction braking for the front wheel, and the hydraulic friction braking for the rear wheel. A regenerative braking co-operative control algorithm is suggested for the regenerative braking and friction braking, which distributes the braking torque according to the drivers demand. A vehicle test was performed to evaluate the proposed braking system and cooperative control algorithm.