Jinsung Kim

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

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 increase power transmitting efficiency. The new clutch actuator has self-energizing mechanism to amplify the normal force applied on the contact surfaces for the engagement. It allows the clutch module to consume less amount of energy for actuating the overall system. The equations of motion of the clutch mechanism coupled with a dc motor are represented to capture the essential dynamics. By using the proposed model, a model-based position-tracking controller is developed for the engagement of the clutch. Also, passivity analysis of the actuator system is performed to prevent the clutch from being stuck. Finally, the self-energizing effect and torque transmissibility of the proposed system and motion controller are validated experimentally.

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

Automated Manual Transmission vehicles are generally 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 control performance in order to guarantee smooth engagement of the clutch. This article proposes the control architecture that consists of the speed control for synchronization and the torsion control for reducing shift shocks incorporating a shaft torque observer. The proposed control structure assures a fast engagement while preventing an abrupt change in vehicle acceleration at the same time.

Design of estimators for the output shaft torque of automated manual transmission systems

This study mainly focuses on the accurate estimation of the output shaft torque - and thus the clutch torque - of the automated manual transmissions as well as dual clutch transmissions, using the data available in the current production vehicles. The required information includes the nominal engine torque map and measurements of engine speed, clutch speed, and wheel speed. Utilizing the above-mentioned information, based on the design of four types of observers (unknown input observer, shaft compliance observer, synthesis of these two types of observers, and an adaptive observer), several methods to obtain the torque estimation without additional cost are developed to improve the feedback control performance of the clutch actuators and thus the vehicle launching and gear shift qualities. The stability of the proposed observers is investigated, and a set of assessments to confirm the performance of the observer system is arranged via simulation.

Gear shift control of Dual Clutch Transmissions with a torque rate limitation trajectory

Gearshift control is one of the main functions of automotive transmissions. The proposed control utilizes the functionality of Dual Clutch Transmissions (DCTs) that two control inputs are available incorporating each other. During gearshift operation, each clutch is controlled uni-directionally to prevent undesirable effects such as dead zone nonlinearity, saturation, and etc. Even though they have such a constraint, the desired clutch profile is tracked well via cross-coupling effect of two actuators. In addition, engine torque is reduced based upon the predetermined target engine speed. A simple proportional-integrative (PI) controller is implemented for a feedback control of the proposed gear shifting management. Simulation results show that gear shifting is performed without excessive oscillations of the shaft torque.

The integrated vehicle longitudinal control system for ABS and TCS

This paper proposes the vehicle longitudinal controller for the Anti-lock Braking System(ABS) and Traction Control System(TCS). The sliding mode control scheme without a sign function is used to design a controller. Instead of a sign function, the adaptation mechanism is used to reduce the actuator chattering as a problem of the sliding mode control. The proposed systems use the equivalent model from engine to wheel to control the brake and engine actuator. Using the integrated logic frame, it reduces the computation load of Electrical Control Unit(ECU) equipped on the vehicle and make integrating a variety of vehicle stability controllers such as ABS, TCS, and ESC(Electronic Stability Control) more easily. The proposed systems are made up of three sub-systems, which are the vehicle state estimator, vehicle state controller and vehicle actuator controller. The performance of the proposed system is verified with a variety of standard ABS and TCS test conditions using the CarSim.

Design of Self-Energizing Clutch Actuator for Dual-Clutch Transmission

A novel dry clutch actuator for the dual-clutch transmission (DCT) using self-energizing principle is suggested. A mathematical model of the actuator and the inclusive DCT driveline is developed. The magnitude of torque amplification obtained by the self-energizing effect is studied, and it is verified via experiments by comparing the calculated and the empirical gains. Also, by analyzing the characteristics of the energy consumption in actuator motors during the vehicle launch and gear shifts, the application potential for the self-energizing clutch actuator is examined. Such work is done both through simulation and dynamometer experiments. The simulation is conducted by using the driveline and self-energizing actuator model developed by using MATLAB/Simulink. The hardware-in-the-loop experiments are conducted with the driveline dynamometer that is designed and constructed exclusively for the self-energizing clutch actuator and DCT to experimentally demonstrate the suitability of the suggested actuator for DCT.

Design of a robust internal-loop compensator of clutch positioning systems

This paper proposes a control scheme based on robust internal-loop compensator for a clutch positioning system. The purpose of control is to achieve a precise position control of automotive dry-clutch actuator system module. Overall system consists of the electric motor and the mechanical subsystem. A set of dynamic model is developed and validated experimentally. Robust internal-loop compensator is used to compensate unmodeled effect and unknown nonlinearities. Simulation and experimental results show that the proposed scheme has a better performance and tracking accuracy compared with simple PID controller.

Nonlinear estimation method of a self-energizing clutch actuator load

Clutch torque estimation is an important problem in automotive transmission control. The self-energizing clutch actuator system has a novel mechanism to amplify the clutch torque for reducing actuation energy. The nonlinear disturbance observer is designed such that the clutch torque is estimated with guaranteeing asymptotic convergence by using the actuation motor measurement signal. The simulation result shows that the developed method is useful to identify the load characteristics of a self-energizing clutch actuator system in comparison with the result of proportional-integrative type observer.

Nonlinear Torque Observer for a Self-Energizing Clutch Actuator Using a Reaction Torque Estimation Approach

Clutch torque estimation is an important problem in automotive transmission control. Particularly, a self-energizing clutch actuator system has a novel mechanism to amplify the clutch torque for reducing actuation energy. Instead of low energy consumption, the clutch torque is highly sensitive to the actuator stroke, which makes the torque detection difficult. The nonlinear disturbance observer is designed such that the clutch torque is estimated with guaranteeing asymptotic convergence by using the actuation motor position signal. This type of observer is based on the reaction torque estimation approach with respect to the actuator dynamics without considering vehicle driveline information. The experimental results show that the developed method is useful to identify the load characteristics of a self-energizing clutch actuator system.

Periodic adaptive disturbance observer for a Permanent Magnet Linear Synchronous Motor

This paper proposes a periodic adaptive disturbance observer (PADOB) to control a PMLSM (Permanent Magnet Linear Synchronous Motor). The PADOB consists of a classical linear DOB and an adaptive mechanism which has been known as the periodic adaptive learning control (PALC). The key idea is to compensate parametric errors between the actual plant and the nominal model of DOB and disturbance forces such as the friction and detent force. The PADOB can improve the instability problem occurred by updating parameters of nominal model in the DOB directly. Through simulation test of the PMLSM, the validity of the PADOB is illustrated.