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Practical vehicle rollover avoidance control using energy method
Taylor Francis 2008 Vehicle system dynamics Vol.46 No.4
<P> 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 size sport utility vehicle up to a speed of 110 km h-1. The test results show that the control algorithm prevents the vehicle rollover very successfully without any noticeable false activation or over correction resulting in severe under steer. Also, the controlled wheel speed shows a very stable and smooth trace.</P>
Jiwon Oh,Seibum B. Choi 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
This paper suggests a dry dual clutch transmission actuator controller for simultaneous kissing point identification by using multiple sliding surfaces, so that the actuator motor positions at the clutch kissing point of both clutches can be estimated during the first launching after the car starts. Such maneuver can be especially advantageous for the vehicles without ROM that keeps the recent kissing point estimations. Separate multiple sliding surface controllers are designed for each actuator, and PI-type actuator motor model-based observers are designed to swiftly identify the kissing point position relative to the initial motor position measured by incremental encoders attached to each actuator motor. Also, methodologies to reduce the jerk that may arise from the simultaneous kissing point identification are suggested. The controller and estimation performance is verified by taking the entire driveline with the forward and reverse engine torque map, physical parameters of the transmission, and actuator model into consideration, and simulations are conducted with the inclusion of sensor measurement noise and friction model to reflect realistic vehicle driveline using MATLAB/Simulink.
MODEL-BASED SENSOR FAULT DIAGNOSIS OF VEHICLE SUSPENSIONS WITH A SUPPORT VECTOR MACHINE
Kicheol Jeong,Seibum Choi 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.5
In this paper, a means of generating residuals based on a quarter-car model and evaluating them using a support vector machine (SVM) is proposed. The proposed model-based residual generator shows very robust performance regardless of unknown road surface conditions. In addition, an SVM classifier without empirically set thresholds is used to evaluate the residuals. The proposed method is expected to reduce the effort required to design fault diagnosis algorithms. While an unknown input observer is used to generate the residual, the relative velocity of the vehicle suspension is obtained additionally. The proposed algorithm is verified using commercial vehicle simulator Carsim with Matlab & Simulink. As a result, the fault diagnosis algorithm proposed in this paper can detect sensor faults that cannot be detected by a limit checking method and can reduce the effort required when designing algorithms.
ENGINE NET TORQUE COMPENSATION THROUGH DRIVELINE TORQUE ESTIMATION IN A PARALLEL HYBRID VEHICLE
Jinrak Park,Seibum Choi,Jiwon Oh,Jeongsoo Eo 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.3
In recent years, interest in smart and green vehicles has increased. There are many cases where engine net torque related control is performed when building smart and green car systems. Speed tracking control in autonomous driving, or optimal transmission shift control is an example. The engine net torque is the sum of the engine indicated torque, accessory load torque, and frictional torque, and the starter motor torque in the case of a parallel hybrid vehicle. However, the estimation error of these torque items can cause the estimation error of the engine net torque. In this paper, a compensation method for the slowly varying uncertainty of the engine net torque in a parallel hybrid vehicle using a multiplicative constant is proposed. The adaptation of the multiplicative constant is conducted using the amount of change in the engine net torque estimated in the backward direction of the driveline. The proposed algorithm is verified based on production vehicle data.
Adaptive slip engagement control of a dry clutch using a clutch torque estimator
Jinrak Park,Seibum Choi,Jiwon Oh,Jeongsoo Eo 제어로봇시스템학회 2018 제어로봇시스템학회 국제학술대회 논문집 Vol.2018 No.10
A dry clutch is an important part in a vehicle powertrain system and the dry clutch is primarily utilized for small and medium sized vehicles. The slip engagement is a method of engaging a clutch in a state where the speeds of both sides of the clutch are different. When a clutch is slipping, energy loss due to clutch friction, and clutch wear occurs. Therefore, it is necessary to control a clutch precisely in slip engagement of a clutch. A clutch friction model is needed to implement feedforward control in clutch slip engagement control, but there are some uncertain parameters in a clutch friction model. In this study, a clutch friction coefficient and a clutch touch point are represented as uncertain parameters of a clutch friction model. Thus, a simultaneous adaptation method of a clutch friction coefficient and a clutch touch point in a clutch friction model, and a feedforward control method of slip engagement of a dry clutch using the adaptation method are proposed in this study. The proposed adaptive control algorithm was verified with the slip engagement simulation of a dry engine clutch in a parallel hybrid vehicle in the MATLAB/Simulink environment.
APPARATUS FOR IDENTIFICATION OF FRICTIONAL AND THERMAL CHARACTERISTICS OF A WET CLUTCH
신승인,김동현,Seibum Choi 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.6
This paper describes the configuration of an apparatus for fundamental research on frictional characteristics for wet clutch control. The friction coefficient usually varies depending on the friction speed, the temperature of the friction surface, and the pressing force. The design and configuration for accurately measuring each major variable were presented. There is a fluid circulation system to implement an environment similar to an actual wet clutch system. It is designed to analyze the friction characteristics by maintaining the fluid film dynamics in a steady-state or to simulate the clutch engagement by controlling the speed of the motor. A friction coefficient map for any multi-disc clutch could be obtained with the presented apparatus, and a map of an automatic transmission clutch is obtained as an example. The experimental result shows the variables of the friction coefficient were the friction speed and the temperature of the friction surface, and in particular, it increased linearly with the temperature of the friction surface within the experimental range.