• Journal of Electrical Engineering and Technology
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• v.8 no.4
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• pp.899-910
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• 2013

This paper presents a novel lateral stability control system for electric vehicle based on sideslip angle estimation through Kalman filter using the integration of a single antenna GPS receiver and yaw rate sensor. Using multi-rate measurements including yaw rate and course angle, time-varying parameters disappear from the measurement equation of the proposed Kalman filter. Accurate sideslip angle estimation is achieved by treating the combination of model uncertainties and external disturbances as extended states. Active front steering and direct yaw moment are integrated to manipulate sideslip angle and yaw rate of the vehicle. Instead of decoupling control design method, a new control scheme, "two-input two-output controller", is proposed. The extended states are utilized for disturbance rejection that improves the robustness of lateral stability control system. The effectiveness of the proposed methods is verified by computer simulations and experiments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.446-467
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• 2012

In this paper, the analysis and design of a motion simulator (based on the approach taken by interactive virtual reality (VR) entertainment systems) is conducted. The main components of the system include a bilateral control interface, simulation and a motion simulator control scheme. The space entertainment system uses a virtual environment that enables operators to feel the actual feedback sensing and distorted motion from the virtual environment, just as they would in the real environment. The space entertainment system integrates the dynamics of the motion simulator and the virtual environment and the operator maneuvers a steering wheel to interact with the system. The multiple bilateral control schemes employ a dynamical controller, which is designed by considering the velocity and acceleration that the operator imposes on the joystick, the environmental changes imposed on the motion simulator. In addition, we develop a calculated method to evaluate the Ratio of the simulation results. It is shown that the proposed control scheme can improve the performance of the visual entertainment system. Experiments are conducted on the virtual reality entertainment system to validate the theoretical developments.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.314-324
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• 2020

Due to the nonlinearity and environmental uncertainties, the design of the ship's steering controller is a long-term challenge. The purpose of this study is to design an intelligent autopilot based on Extended Kalman Filter (EKF) trained Radial Basis Function Neural Network (RBFNN) control algorithm. The newly developed free running model scaled surface vessel was employed to execute the motion control experiments. After describing the design of the EKF trained RBFNN autopilot, the performances of the proposed control system were investigated by conducting experiments using the physical model on lake and simulations using the corresponding mathematical model. The results demonstrate that the developed control system is feasible to be used for the ship's motion control in the presences of environmental disturbances. Moreover, in comparison with the Back-Propagation (BP) neural networks and Proportional-Derivative (PD) based control methods, the EKF RBFNN based control method shows better performance regarding course keeping and trajectory tracking.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.599-605
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• 2017

For an unmanned vehicle to be driven on the off-road terrain, it is necessary to consider the vehicle's stability. This paper suggests a path tracking controller for simulation of real-time vehicle stability analysis. The path tracking controller uses the preview distance to track the given trajectory. The disturbance moment is estimated using the yaw moment observer, and this information is used for compensation in the yaw moment control. On a curved path, the vehicle's desired velocity is determined from the curvature of the path. Because the vehicle is equipped with six independent motor driven wheels, the driving torques are distributed on all the wheels. The effectiveness of the path tracking controller is verified using ADAMS/MATLAB co-simulation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.152-152
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• 2017

본 연구에서는 비례제어밸브를 이용한 자율주행 트랙터 조향 시스템 제어를 위하여 저가의 임베디드 시스템을 사용한 제어기를 개발하였다. 차륜의 조향각 측정을 위하여 전륜 킹핀에 포텐시오미터를 설치하였으며, 비례제어밸브는 -10 ~ +10V의 전압으로 밸브 스풀의 위치제어를 수행하도록 하였다. 조향각 측정과 비례제어밸브의 위치제어를 위하여 각각에 AT90CAN128 AVR보드를 사용하였으며, CAN통신으로 조향각 데이터가 비례제어밸브 제어용 데이터로 전송될 수 있도록 하였다. 비례제어밸브 제어 보드에는 DAC기능을 추가하였으며 0 ~ 5V의 출력을 -10 ~ +10V의 전압으로 변환해 주는 인터페이스회로를 추가하였다. 일반적으로 GPS 등의 데이터 수신율이 20 Hz인 점을 감안하여 비례제어 밸브는 50 ms의 주기로 P-제어를 수행할 수 있도록 하였다. 향후 트랙터의 방향각을 설정하는 또 하나의 시스템으로부터 목표 조향각을 부여받는 것을 가상하여 별도의 MCU를 통해 목표 조향각을 송신한 후, 조향 유압실린더에 의한 전륜의 조향각 시간 응답 특성을 조사하였다. 실험은 트랙터의 전륜을 지면으로부터 들어올린 무 부하 상태에서 진행하였으며, 목표 조향각은 $7.5^{\circ}$, $15.0^{\circ}$, $22.5^{\circ}$ 등 3단계로 변경하며 시간응답 특성을 측정하였다. 최대 오버슈트 11%, 최소 오버슈트 8.6%, 정상상태 오차 약 $0.825^{\circ}$, 시정수(Time Constant)는 3단계의 목표 조향각 설정에서 각각 0.706초, 0.488초, 0.38초로 나타났다.

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.226-235
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• 1995

An unmanned speed sprayer was developed using a remote control and an inductive cable guidance systems to protect operators and environment from hazardous pesticides. The sprayer consists of a remote control system, an induction system, obstacle detectors, control actuators and an one-chip microcomputer. The sprayer can be operated by the induction guidance and/or remote control. The following summarize characteristics of the developed speed sprayer. 1) Both the remote control and the induction guidance operation were possible with the developed speed sprayer. 2) Sixteen functions of the forwarding, backing, halting, steering, 3-way valve for nozzles and fan operating etc. were utilized on the remote control system. 3) It was concluded that the DTMF method, having less transmitting error, performed better than the FSK method for an agricultural remote controller. A radio station may be necessary. 4) The digital inductive guidance system, consisting of five low-impedance detection coils and a window comparator circuit, performed better than the analog detecting system, guiding route using inductive voltage differential from tow detection coils.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1547-1552
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• 2008

The tip of these catheter with straight needles is not able to reach in the vicinity of the disc bulging, which are the cause of the low back pain and because the far indirect radio-frequency treatment results in the decompression, the nucleoplasty has the limit. Many incurable diseases has not been solved due to the unexistence of the advanced technique for the MIS human body catheter device. To increase the possibility of nucleoplasty, the needle tip should be located at the closest area of the lesion. For this reason, the best way to increase the success rate of the operation is that the needle tip should access 3-dimensionally to the operating field as soon as possible. To achieve this aim, our studies are restricted as follows: 1) the SMA catheter design to control the 3-dimensional direction, 2) the security of the immediate response by the positive control of the SMA element thermal distribution using Peltier thermoelectric elements, 3) the aquisition of the control data by monitoring the relationship between the temperature of SMA element and the displacement, and 4) the design of the controller to guarantee the accurate location.

• Journal of IKEEE
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• v.18 no.2
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• pp.282-290
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• 2014

This paper presents the design of embedded electrical power control unit for Personal Electrical Vehicle(PEV). The embedded unit is designed using PIC18F8720 processor, 16Mb flash ROM, 32Mb SDRAM and signal condition circuits. The proposed PEV consists of 4KW in-wheel Brushless DC Motor(BLDCM), 3 phase voltage source inverter with the $180^{\circ}$ conduction space vector PWM method, PID speed controller and the embedded control unit. The PEV has mechanical manufacture of inverse 3 wheel system, which is applied by the in-wheel BLDCM and steering mechanism with tilting function. Also, the performances of the proposed embedded electrical power control unit are verified through the lab experiment and road driving test of PEV.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.621-626
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• 2019

The driver's steering wheel maneuver is a typical disturbance that causes excessive body motion and traveling instability of a vehicle. Abrupt and extreme operation can cause rollover depending on the geometric and dynamic characteristics, e.g., SUV vehicles. In this study, to cope with the performance limitation of conventional cars, fundamental research on the structurization of a control system was performed as follows. Mathematical modeling of the lateral behavior induced by driver input was carried out. A controller was designed to reduce the body motion based on this model. An algorithm was applied to secure robust control performance against modeling errors due to parameter uncertainty, $H_{\infty}$. Using the decoupled 1/4 car, a dynamic load simulating model considering the body moment was suggested. The simulation result showed the validity of the load-simulating model. The framework for a lateral behavior control system is proposed, including an experimental 1/4 vehicle unit, load simulating module, suspension control module, and hardware-in-the-loop simulation technology.

• KIPS Transactions on Computer and Communication Systems
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• v.6 no.6
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• pp.271-280
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• 2017

In this paper, we propose a new safety system composed of wearable devices, driver's seat belt, and integrating controllers. The wearable device and driver's seat belt capture driver's biological information, while the integrating controller analyzes captured signal to alarm the driver or directly control the car appropriately according to the status of the driver. Previous studies regarding driver's safety from driver's seat, steering wheel, or facial camera to capture driver's physiological signal and facial information had difficulties in gathering accurate and continuous signals because the sensors required the upright posture of the driver. Utilizing wearable sensors, however, our proposed system can obtain continuous and highly accurate signals compared to the previous researches. Our advanced wearable apparatus features a sensor that measures the heart rate, skin conductivity, and skin temperature and applies filters to eliminate the noise generated by the automobile. Moreover, the acceleration sensor and the gyro sensor in our wearable device enable the reduction of the measurement errors. Based on the collected bio-signals, the criteria for identifying the driver's condition were presented. The accredited certification body has verified that the devices has the accuracy of the level of medical care. The laboratory test and the real automobile test demonstrate that our proposed system is good for the measurement of the driver's condition.