seibum choi | KAIST - Academia.edu (original) (raw)

Papers by seibum choi

Research paper thumbnail of Design and Experimental Implementation of Longitudinal Control for a Platoon of Automated Vehicles

Journal of Dynamic Systems, Measurement, and Control, 1998

This paper presents the design and experimental implementation of a longitudinal control system f... more This paper presents the design and experimental implementation of a longitudinal control system for the operation of automated vehicles in platoons. The control system on each vehicle is designed to have a hierarchical structure and consists of an upper level controller and a lower level controller. The upper controller determines the desired acceleration for each vehicle in the platoon so as to maintain safe string-stable operation even at very small intervehicle spacing. The lower controller utilizes vehicle-specific parameters and determines the throttle and/or brake commands required to track the desired acceleration. A special challenge handled in the design of the lower level controller is low-speed operation that involves gear changes and torque converter dynamics. The paper also presents the design of longitudinal intra-platoon maneuvers that are required in order to allow any car in the platoon to make an exit. The paper presents extensive experimental results from the publ...

Research paper thumbnail of Sensorless adaptive speed control of a permanent-magnet dc motor for anti-lock brake systems

International Journal of Automotive Technology

Research paper thumbnail of Adaptive neural network based fuzzy control for a smart idle stop and go vehicle control system

International Journal of Automotive Technology, 2012

ABSTRACT

Research paper thumbnail of Vehicle roll and pitch angle estimation using a cost-effective six-dimensional inertial measurement unit

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2013

The purpose of this paper is to estimate accurately the vehicle attitudes, i.e. the vehicle roll ... more The purpose of this paper is to estimate accurately the vehicle attitudes, i.e. the vehicle roll and pitch angles. It is assumed that a set of data obtained from a low-price six-dimensional inertial measurement unit is available. This includes the linear acceleration of the vehicle and the angular rates of all axes. In addition, the observer exploits the data from the wheel speed sensors, and the steering-wheel angle, which are already available for recent production cars. Using the above, based on the combination of the velocity kinematics and pseudointegration of the angle kinematics, a novel scheme for reference angle selection dependent on the cornering-stiffness adaptation is adopted to observe the angles. The stability of each component of the proposed observer is investigated, and a set of assessments to confirm the performance of the entire system is arranged via experiments using a real production sport utility vehicle.

Research paper thumbnail of A robust road bank angle estimation based on a

Research paper thumbnail of Development of a camless engine valve actuator system for robust engine valve timing control

International Journal of Vehicle Systems Modelling and Testing, 2012

In this paper, a camless engine valve actuator (CEVA) system for robust engine valve timing contr... more In this paper, a camless engine valve actuator (CEVA) system for robust engine valve timing control is presented. A particularly challenging control obstacle, shown in hydraulic actuation system for camless engine valve actuators, is the sluggish response of valve actuators at a cold operating condition. This is mainly due to the characteristics of oil viscosity with respect to temperature changes. At a low temperature condition, CEVA shows the very sluggish response. The retarded valve opening and closing timing, by CEVA's slow response at low temperature, cause an increase in pollutant emission and cylinder temperature during engine operation. In order to avoid these adverse effects by retarded timing, the new valve timing controller is proposed to control opening timing and closing timing, which is robust against temperature variations. A proposed valve timing controller is for guaranteeing the valve timing repeatability without using expensive position sensors. Experimental results indicate the feasibility of a fully variable valve timing control and CEVA system which can be constructed at a low cost.

Research paper thumbnail of A driver model for vehicle lateral dynamics

International Journal of Vehicle Design, 2011

There have been several studies aiming to develop a realistic driver model in accordance with the... more There have been several studies aiming to develop a realistic driver model in accordance with the increased interest in vehicle safety issues and in computer simulation for a vehicle design. This study is especially considering the human driver's steering process; path planning, feed-forward steering, and preview feedback steering. Important human factors, such as the view angle and the neuromuscular system, are also regarded. The suggested driver model is simulated based on the CarSim vehicle model in a Simulink environment. The simulation results are then compared to the actual vehicle test data and to the driving simulator test data with regard to the four human driver levels. The driver model suggested in this study represents the human steering behaviour and well matches the real vehicle test data.

Research paper thumbnail of Robust control of electronic wedge brake with adaptive pad friction estimation

International Journal of Vehicle Design, 2013

This paper suggests an adaptation scheme for robust control of Electronic Wedge Brake (EWB) and e... more This paper suggests an adaptation scheme for robust control of Electronic Wedge Brake (EWB) and estimation of pad friction-coefficient. The Electronic Wedge Brake is highly energy-effective as it uses selfreinforcement. But accordingly, it can be sensitive to the parametric variation, particularly to the pad friction-coefficient. The suggested scheme reduces the effect of the variation of pad friction-coefficient on system robustness and provides a way of estimation of the friction-coefficient in real time. The series of simulation results verify the performance of suggested control scheme.

Research paper thumbnail of Design and Modeling of a Clutch Actuator System With Self-Energizing Mechanism

Mechatronics, IEEE/ASME Transactions on

Abstract—The engineering technology for automotive systems is currently edging toward improving f... more Abstract—The engineering technology for automotive systems is currently edging toward improving fuel economy. Transmission is one of the major parts to determine overall energy efficiency. The goal of this paper is to investigate the feasibility of a new clutch actuator in order to ...

Research paper thumbnail of Control of dry clutch engagement for vehicle launches via a shaft torque observer

Abstract— Automated Manual Transmission vehicles are gen-erally equipped with the servo-actuated ... more Abstract— Automated Manual Transmission vehicles are gen-erally equipped with the servo-actuated clutch engagement system. In that system, shift quality depends on the engaging time and controlling the clutch normal force. It is therefore crucial to pay attention to the ...

Research paper thumbnail of Robust throttle control of automotive engines: theory and experiment

Journal of dynamic systems, measurement, and …, 1996

An adaptive, sliding control algorithm is developed for automated throttle control of an IC engin... more An adaptive, sliding control algorithm is developed for automated throttle control of an IC 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 ...

Research paper thumbnail of Design of 3wheeler chassis with expansible crash box

The more expensive gas expense is, the more endeavor many investigators are through a variety of ... more The more expensive gas expense is, the more endeavor many investigators are through a variety of methods which are application of engine managements and hybrid system or augmentation of efficiency of mechanical parts. But, these methods acquired a lot of time, costs, and efforts are not adequate in this emergency. The unique method which is simple and certain is decreasing mass of vehicle. However, the smaller and the lighter the vehicle is, the more dangerous the passenger is because of insufficiency of crash room in bumper to bumper. In this study, ultra light 3wheeler with active safety system which is called expansible crash boxis studied and developed. Using the 6061 aluminum frame, all mass of vehicle is max. 250kg and applying the crash simulation tools like LS-DYNA to demonstrate the safety of ultra light 3 wheeler with the expansible crash box. In the expansible crash box beam, elastic buckling theory give the first step toward the solution of the question of absorption of crash energy and a variety of techniques like groove pattern processing are applied. The more studies should be practiced from applying this study, and the unique safety systems which are adapted to ultra light vehicles are developed so that ultra light vehicles will be of practical use.

Research paper thumbnail of Lateral acceleration compensation of a vehicle based on roll angle estimation

This paper demonstrates a method for compensating the gravity component of the lateral accelerati... more This paper demonstrates a method for compensating the gravity component of the lateral acceleration through the estimation of the roll angle. The lateral acceleration has a direct influence on the road disturbance and suspension motion by driver's steering input. It is difficult to differenciate the bias(gravity component) induced by the road bank disturbance and suspension motion from the actual lateral acceleration measured by a sensor. Although the roll rate sensor can estimate the roll angle via the integration, it has several limitations concerning its use. Because there is no roll rate sensor or roll angle sensor in usual vehicles and the integration may cause the sensor drift problem. In this paper, the state index that implicates whether the state of the vehicle is in the transient region or steady state region, is defined. The roll angle is estimated by integrating the suspension angle rate and kinematic roll angle through switching of the state index. The gravity component induced by roll angle is substracted from the measured lateral acceleration components. And the side-slip angle is estimated to verify the influence of the compensated lateral acceleration. These works are verified using CarSim program with variety of road environments and steering inputs.

Research paper thumbnail of Design and Experimental Implementation of Longitudinal Control for a Platoon of Automated Vehicles

Journal of Dynamic Systems, Measurement, and Control, 1998

This paper presents the design and experimental implementation of a longitudinal control system f... more This paper presents the design and experimental implementation of a longitudinal control system for the operation of automated vehicles in platoons. The control system on each vehicle is designed to have a hierarchical structure and consists of an upper level controller and a lower level controller. The upper controller determines the desired acceleration for each vehicle in the platoon so as to maintain safe string-stable operation even at very small intervehicle spacing. The lower controller utilizes vehicle-specific parameters and determines the throttle and/or brake commands required to track the desired acceleration. A special challenge handled in the design of the lower level controller is low-speed operation that involves gear changes and torque converter dynamics. The paper also presents the design of longitudinal intra-platoon maneuvers that are required in order to allow any car in the platoon to make an exit. The paper presents extensive experimental results from the publ...

Research paper thumbnail of Sensorless adaptive speed control of a permanent-magnet dc motor for anti-lock brake systems

International Journal of Automotive Technology

Research paper thumbnail of Adaptive neural network based fuzzy control for a smart idle stop and go vehicle control system

International Journal of Automotive Technology, 2012

ABSTRACT

Research paper thumbnail of Vehicle roll and pitch angle estimation using a cost-effective six-dimensional inertial measurement unit

Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2013

The purpose of this paper is to estimate accurately the vehicle attitudes, i.e. the vehicle roll ... more The purpose of this paper is to estimate accurately the vehicle attitudes, i.e. the vehicle roll and pitch angles. It is assumed that a set of data obtained from a low-price six-dimensional inertial measurement unit is available. This includes the linear acceleration of the vehicle and the angular rates of all axes. In addition, the observer exploits the data from the wheel speed sensors, and the steering-wheel angle, which are already available for recent production cars. Using the above, based on the combination of the velocity kinematics and pseudointegration of the angle kinematics, a novel scheme for reference angle selection dependent on the cornering-stiffness adaptation is adopted to observe the angles. The stability of each component of the proposed observer is investigated, and a set of assessments to confirm the performance of the entire system is arranged via experiments using a real production sport utility vehicle.

Research paper thumbnail of A robust road bank angle estimation based on a

Research paper thumbnail of Development of a camless engine valve actuator system for robust engine valve timing control

International Journal of Vehicle Systems Modelling and Testing, 2012

In this paper, a camless engine valve actuator (CEVA) system for robust engine valve timing contr... more In this paper, a camless engine valve actuator (CEVA) system for robust engine valve timing control is presented. A particularly challenging control obstacle, shown in hydraulic actuation system for camless engine valve actuators, is the sluggish response of valve actuators at a cold operating condition. This is mainly due to the characteristics of oil viscosity with respect to temperature changes. At a low temperature condition, CEVA shows the very sluggish response. The retarded valve opening and closing timing, by CEVA's slow response at low temperature, cause an increase in pollutant emission and cylinder temperature during engine operation. In order to avoid these adverse effects by retarded timing, the new valve timing controller is proposed to control opening timing and closing timing, which is robust against temperature variations. A proposed valve timing controller is for guaranteeing the valve timing repeatability without using expensive position sensors. Experimental results indicate the feasibility of a fully variable valve timing control and CEVA system which can be constructed at a low cost.

Research paper thumbnail of A driver model for vehicle lateral dynamics

International Journal of Vehicle Design, 2011

There have been several studies aiming to develop a realistic driver model in accordance with the... more There have been several studies aiming to develop a realistic driver model in accordance with the increased interest in vehicle safety issues and in computer simulation for a vehicle design. This study is especially considering the human driver's steering process; path planning, feed-forward steering, and preview feedback steering. Important human factors, such as the view angle and the neuromuscular system, are also regarded. The suggested driver model is simulated based on the CarSim vehicle model in a Simulink environment. The simulation results are then compared to the actual vehicle test data and to the driving simulator test data with regard to the four human driver levels. The driver model suggested in this study represents the human steering behaviour and well matches the real vehicle test data.

Research paper thumbnail of Robust control of electronic wedge brake with adaptive pad friction estimation

International Journal of Vehicle Design, 2013

This paper suggests an adaptation scheme for robust control of Electronic Wedge Brake (EWB) and e... more This paper suggests an adaptation scheme for robust control of Electronic Wedge Brake (EWB) and estimation of pad friction-coefficient. The Electronic Wedge Brake is highly energy-effective as it uses selfreinforcement. But accordingly, it can be sensitive to the parametric variation, particularly to the pad friction-coefficient. The suggested scheme reduces the effect of the variation of pad friction-coefficient on system robustness and provides a way of estimation of the friction-coefficient in real time. The series of simulation results verify the performance of suggested control scheme.

Research paper thumbnail of Design and Modeling of a Clutch Actuator System With Self-Energizing Mechanism

Mechatronics, IEEE/ASME Transactions on

Abstract—The engineering technology for automotive systems is currently edging toward improving f... more Abstract—The engineering technology for automotive systems is currently edging toward improving fuel economy. Transmission is one of the major parts to determine overall energy efficiency. The goal of this paper is to investigate the feasibility of a new clutch actuator in order to ...

Research paper thumbnail of Control of dry clutch engagement for vehicle launches via a shaft torque observer

Abstract— Automated Manual Transmission vehicles are gen-erally equipped with the servo-actuated ... more Abstract— Automated Manual Transmission vehicles are gen-erally equipped with the servo-actuated clutch engagement system. In that system, shift quality depends on the engaging time and controlling the clutch normal force. It is therefore crucial to pay attention to the ...

Research paper thumbnail of Robust throttle control of automotive engines: theory and experiment

Journal of dynamic systems, measurement, and …, 1996

An adaptive, sliding control algorithm is developed for automated throttle control of an IC engin... more An adaptive, sliding control algorithm is developed for automated throttle control of an IC 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 ...

Research paper thumbnail of Design of 3wheeler chassis with expansible crash box

The more expensive gas expense is, the more endeavor many investigators are through a variety of ... more The more expensive gas expense is, the more endeavor many investigators are through a variety of methods which are application of engine managements and hybrid system or augmentation of efficiency of mechanical parts. But, these methods acquired a lot of time, costs, and efforts are not adequate in this emergency. The unique method which is simple and certain is decreasing mass of vehicle. However, the smaller and the lighter the vehicle is, the more dangerous the passenger is because of insufficiency of crash room in bumper to bumper. In this study, ultra light 3wheeler with active safety system which is called expansible crash boxis studied and developed. Using the 6061 aluminum frame, all mass of vehicle is max. 250kg and applying the crash simulation tools like LS-DYNA to demonstrate the safety of ultra light 3 wheeler with the expansible crash box. In the expansible crash box beam, elastic buckling theory give the first step toward the solution of the question of absorption of crash energy and a variety of techniques like groove pattern processing are applied. The more studies should be practiced from applying this study, and the unique safety systems which are adapted to ultra light vehicles are developed so that ultra light vehicles will be of practical use.

Research paper thumbnail of Lateral acceleration compensation of a vehicle based on roll angle estimation

This paper demonstrates a method for compensating the gravity component of the lateral accelerati... more This paper demonstrates a method for compensating the gravity component of the lateral acceleration through the estimation of the roll angle. The lateral acceleration has a direct influence on the road disturbance and suspension motion by driver's steering input. It is difficult to differenciate the bias(gravity component) induced by the road bank disturbance and suspension motion from the actual lateral acceleration measured by a sensor. Although the roll rate sensor can estimate the roll angle via the integration, it has several limitations concerning its use. Because there is no roll rate sensor or roll angle sensor in usual vehicles and the integration may cause the sensor drift problem. In this paper, the state index that implicates whether the state of the vehicle is in the transient region or steady state region, is defined. The roll angle is estimated by integrating the suspension angle rate and kinematic roll angle through switching of the state index. The gravity component induced by roll angle is substracted from the measured lateral acceleration components. And the side-slip angle is estimated to verify the influence of the compensated lateral acceleration. These works are verified using CarSim program with variety of road environments and steering inputs.