• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.856-864
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• 2008

This paper describes a vehicle low speed driving assistant (VLDA) system that is composed of laser scanner. This vehicle is designed for following lead vehicle (LV) without driver's operation. The system is made up several component systems that are based on unmanned ground vehicle (UGV). Each component system is applied to use advanced safety vehicle developed to complete UGV system. VLDA system was divided into vehicle control system and obstacle detecting system. The obstacle detecting system calculate distance and angle of LV and transmit these data to vehicle control system using front, left and right laser scanners. Vehicle control system makes vehicle control values such as steering angle, acceleration and brake position and control vehicle's movement with steering, acceleration and brake actuators. In this research, we designed VLDA system like as low speed cruise control system and test it on real road environments.

• Wind and Structures
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• v.15 no.3
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• pp.263-283
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• 2012

This paper presents a framework of nonlinear dynamic analysis of a low-speed moving maglev (magnetically levitated) vehicle subjected to cross winds and controlled using a clipped-LQR actuator with time delay compensation. A four degrees-of-freedom (4-DOFs) maglev-vehicle equipped with an onboard PID (Proportional-Integral-Derivative) controller traveling over guideway girders was developed to regulate the electric current and control voltage. With this maglev-vehicle/guideway model, dynamic interaction analysis of a low-speed maglev vehicle with guideway girders was conducted using an iterative approach. Considering the time-delay issue of unsynchronized tuning forces in control process, a clipped-LQR actuator with time-delay compensation is developed to improve control effectiveness of lateral vibration of the running maglev vehicle in cross winds. Numerical simulations demonstrate that although the lateral response of the maglev vehicle moving in cross winds would be amplified significantly, the present clipped-LQR controller exhibits its control performance in suppressing the lateral vibration of the vehicle.

• International Journal of Automotive Technology
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• v.6 no.4
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• pp.359-365
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• 2005

The absolute longitudinal speed of a vehicle is estimated by using data from an accelerometer of the vehicle and wheel speed sensors of a standard 50-tooth antilock braking system. An intuitive solution to this problem is, 'When wheel slip is low, calculate the vehicle velocity from the wheel speeds; when wheel slip is high, calculate the vehicle speed by integrating signal of the accelerometer.' The speed estimator weighted with fuzzy logic is introduced to implement the above concept, which is formulated as an estimation method. And the method is improved through experiments by how to calculate speed from acceleration signal and slip ratios. It is verified experimentally to usefulness of estimation speed of a vehicle. And the experimental result shows that the estimated vehicle longitudinal speed has only a $6\%$ worst-case error during a hard braking maneuver lasting a few seconds.

• Journal of Electrical Engineering and Technology
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• v.8 no.3
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• pp.530-543
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• 2013

This paper describes a control scheme of speed sensorless fuzzy direct torque control (FDTC) of permanent magnet synchronous motor for electric vehicle (EV). Electric vehicle requires fast torque response and high efficiency of the drive. Speed sensorless FDTC In-wheel PMSM drives without mechanical speed sensors at the motor shaft have the attractions of low cost, quick response and high reliability in electric vehicle application. This paper presents a new approach to estimate the speed of in-wheel electrical vehicles based on Model Reference Adaptive System (MRAS). The direct torque control suffers in low speeds due to the effect of changes in stator resistance on the flux measurements. To improve the system performance at low speeds, a PI-fuzzy resistance estimator is proposed to eliminate the error due to changes in stator resistance. High performance sensorless drive of the in-wheel motor based on MRAS with on line stator resistance tuning is established for four motorized wheels electric vehicle and the whole system is simulated by matalb/simulink. The simulation results show the effectiveness of the new control strategy. This proposed control strategy is extensively used in electric vehicle application.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.871-873
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• 2001

The switched reluctance motor (SRM) is gaining much interest as a candidate for electric vehicle for its simple and rugged construction, ability of extremely high-speed operation. This paper is to design and investigate the capabilities of the SRM for low speed electric vehicle (LSEV).

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.179-186
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• 2002

The absolute longitudinal speed of a vehicle is estimated by using vehicle acceleration data from an accelerometer and wheel speed data from standard 50-tooth antiknock braking system wheel speed sensors. An intuitive solution to this problem is, "When wheel slip is low, calculate absolute velocities from the wheel speeds; when wheel slip is high, calculate absolute velocity by integrating the accelerometer." Fuzzy logic is introduced to implement the above idea and a new algorithm of "modified velocities with step integration" is proposed. This algorithm is verified experimentally to estimate speed of a vehicle, and is also shown to estimate absolute longitudinal vehicle speed with a 6% worst-case error during a hard braking maneuver lasting three seconds.

• International Journal of Automotive Technology
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• v.6 no.2
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• pp.161-169
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• 2005

Neck injuries sustained during low speed rear impact are the most commonly sustained traffic injury. Therefore, the analysis of neck injury mechanisms and methods for mitigating and reducing neck injuries during low speed rear impact are a very important issue in the vehicle safety field. In order to find a method to absorb the shock that is transmitted to the occupant, the response of frontal and rear dummy due to the motion of the struck vehicle and the rotational angular displacements of dummies' necks during rear impact at 12km/h speed were investigated using a Working Model 2D. The results suggest that the shock absorption system should be equipped in the bottom of the seat of the vehicle to reduce shock and mitigate neck injury to the occupants.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.10
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• pp.993-1001
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• 2007

An analysis model has been developed to assess running safety of railway vehicle passing curves. By using ADAMS/Rail, a computer analysis has been conducted by changing various parameters according to the track conditions. Analysis results show as follows: A derailment coefficient of left wheel was increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A unload rate of left wheel was also increased according to increase of cant at low speed, while it was decreased as increase of cant at high speed. A wear number of left wheel was increased according to increase of cant at all speed, but only at 35 m/s, it was decreased as increase of cant. A friction coefficient of left wheel was Increased according to increase of cant at all speed, but only at 35 m/s. it was decreased as increase of cant.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.2
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• pp.182-189
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• 2003

We have found that the damage of the front part for a vehicle and that of the rear part for a vehicle are the majority of frequency experienced by the traffic accidents. In conventional bumper system was designed by safety standard regulation at low speed crash. For example there are 2.5 mile and 5 mile bumper. The conventional bumper system was the crash from max 5.5 mile to 3 mile low speed occurs most frequently and results in the highest rate of repairing cost in statistically. On this study, in order to check the damageability and repairability of gas tube bumper system RCAR 15 km/h 40 % offset frontal crash test was adopted in low speed and we have a gas tube bumper parts test and vehicle test with gas tube bumper, we can find gas tube bumper system definitely can improve the damageability and repairability of the vehicles and contribute to down the repairing cost.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.619-624
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• 2006

This paper presents design of a vehicle stop-and-go cruise control strategy based on analyzed results of the manual driving data. Human drivers driving characteristics have been investigated using vehicle driving data obtained from 100 participants on low speed urban traffic ways. The control algorithm has been designed to incorporate the driving characteristics of the human drivers and to achieve natural vehicle behavior of the controlled vehicle that would feel comfortable to the human driver under low speed stop-and-go driving conditions. Vehicle following characteristics of the cruise controlled vehicle have been investigated using a validated vehicle simulator and real driving radar sensor data.