• Journal of Power Electronics
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• v.11 no.4
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• pp.393-400
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• 2011

The main objective of this paper is to control the speed of Nonlinear Hybrid Electric Vehicle (HEV) by controlling the throttle position. Various control techniques such as well known Proportional-Integral-Derivative (PID) controller in conjunction with state feedback controller (SFC) such as Pole Placement Technique (PPT), Observer Based Controller (OBC) and Linear Quadratic Regulator (LQR) Controller are designed. Some Intelligent control techniques e.g. fuzzy logic PD, Fuzzy logic PI along with Adaptive Controller such as Self Organizing Controller (SOC) is also designed. The design objective in this research paper is to provide smooth throttle movement, zero steady-state speed error, and to maintain a Selected Vehicle (SV) speed. A comparative study is carried out in order to identify the superiority of optimal control technique so as to get improved fuel economy, reduced pollution, improved driving safety and reduced manufacturing costs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.62-70
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• 2000

Intelligent vehicles are equipped with radar sensors for collision avoidance. We present a method of suppressing mutual interference among pulse-type radars, where all the radars are standardized. We developed a method of separating the true self-reflection from the false one by controlling the pulse emission of a radar in anorhogonal ON, OFF pattern. Interference signal identified in OFF-intervals is recorded to indicate the positions of the expected ghosts in ON-intervals. PFA and PM are derived for a radar system with I-Q demodulation scheme, where Gaussian noise alone is Rayleigh-distributed and Gaussian noise plus reflected radar pulse are Rician-distributed. The value of the threshold adaptively updated in order to prevent the deterioration of PM. In the experimental result, PFA decreases by an order of 10,000, when compared with the conventional M of N majority voting method.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.163-172
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• 2004

Nowadays, to analyze the dynamic characteristics of the automotive driving system, the computer simulation linked up with VR(Virtual Reality) technology is treated as the useful method with the improvement of computing ability. In this paper, the VR simulation system has been developed to investigate the driving characteristics of the ASV(Advanced Safety Vehicle) equipped with an ACC(Adaptive Cruise Control) system. For the purpose, VR environment which generates 3D graphic and sound information of the vehicle, the road, the facilities, and the terrain has been organized for the driving reality. Mathematical models of vehicle dynamic analysis including the ACC model have been constructed for computer simulation. The ACC modulates the throttle and brake functions to regulate the vehicle speed so that vehicles could keep proper spacing. Also, the real-time simulation algorithm synchronizes vehicle dynamic simulation with the graphic rendering. With the developed VR simulation system, simple scenarios are applied to analyze the dynamic characteristics. It is shown that the VR simulation system could be useful to evaluate the adaptive cruise controlled vehicle on various driving conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.37-45
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• 2011

As vehicles become more intelligent, in-vehicle networking (IVN) systems such as controller area network (CAN) or FlexRay are essential for convenience and safety of drivers. To expand the applicability of IVN systems, attention is currently being focused on the communication between heterogeneous networks such as body networking and chassis networking systems. A gateway based on message mapping method was developed to interconnect FlexRay and CAN networks. However, this type of gateways has the following shortcomings. First, when a message ID was changed, the gateway must be reloaded with a new mapping table reflecting the change. Second, if the number of messages to be transferred between two networks increase, software complexity of gateway increases very rapidly. In order to overcome these disadvantages, this paper presents FlexRay-CAN gateway based on node mapping method. More specifically, this paper presents a node mapping based FlexRay-CAN gateway operation algorithm along with the experimental evaluation for ID change.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.31-35
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• 2000

An nonlinear observer-based longitudinal control law for vehicles is presented in this paper. It is assumed that for vehicle i knows only the distance between vehicle i and the preceding vehicle, i-1. An nonlinear state observer for vehicle I is developed to estimate the velocity and acceleration of the preceding vehicle, i-1. The communication of the position, velocity, and acceleration information is not used in the proposed method. It will be shown by mathematical analysis that the longitudinal control of vehicle can be implemented without an communication of the informations. It will be proven that the observation errors of the nonlinear states converge to zero asymptotically. To show the effectiveness of the proposed method, the simulation results are presented for the longitudinal control of the vehicle.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.175-180
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• 2015

Worldwide, studies on intelligent vehicles for the convenience of drivers have been actively conducted as the number of cars has increased. However, vehicle convenience enabled by buttons lowers the concentration on driving and hence poses as a huge threat to the safety of the driver. The use of one of the convenient features, impaired driving auxiliary equipment, is limited because of its complex usage, and this device also hinders the front view of the driver. This paper proposes a vehicle-control device for controlling the convenient features as well as changes in speed and direction using gestures and motions of the driver. This device consists of an ultrasonic sensor for recognizing movement, an arduino for accepting signal control functions and servo and DC motors apply to various vehicle parts. Firstly, the vehicle-control device was designed using a 3D CAD program known as Solid-works based on the size of the steering wheel. Then, through simulations, a suitable length for minimizing the absorbent between ultrasonic sensors was confirmed using a program known as COMSOL Multiphysics. Finally, simulation results were verified through experiments, and the optimal size of the device was identified through the number of errors.

• ETRI Journal
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• v.41 no.6
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• pp.703-714
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• 2019

Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long-term evolution communication technologies. As the 70-MHz bandwidth in the 5.9-GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance.

• Journal of Drive and Control
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• v.14 no.3
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• pp.8-17
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• 2017

With automobiles sharply increasing in numbers worldwide, we are faced with critical social issues such as traffic accidents, traffic jams, environmental pollution, and economic inefficiency. In response, research on ITS is promoted mainly by regions with advanced automotive industry such as the U.S., Europe, and Japan. While Korea is working on moving forward in the global market through developing and turning to global standards systems related to ASV (Advanced Safety Vehicle), the country is not fully prepared for such projects. The purpose of ACC (Adaptive Cruise Control) is to control a vehicle's longitudinal speed and distance and minimize driver workload. Such a system should be valuable in preventing accidents, as it reduces driver workload in the 21st-century world of telematics created by development of the automobile culture industry. In this light, the thesis presents a method to test and evaluate ACC system and a mathematical method to assess distance. For the proposed test and evaluation, theoretical values are tested with vehicle test and a database is acquired, by using vehicles equipped with an ACC system. Theoretical evaluation criteria for developing ACC system may be used and scenario-specific evaluation methods may find useful application through testing the formula proposed by comparing the database and mathematical method.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.156-158
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• 2018

The inconsistencies between paralleled battery cells are becoming more considerable issue in high capacity battery applications like electric vehicles. Due to differences in state-of-charge (SOC) and internal resistance within individual cells in parallel, charging or discharging current is not appropriately balanced to each cell in terms of SOC, which may shorten the lifetime or sometimes cause safety issues. In this paper, an intelligent cell-balancing algorithm is proposed to overcome the inconsistency issue especially for paralleled battery cells. In this scheme, SOC information collected in the sub-BMS module is sent to the main-BMS module, where the number of parallel cells to be connected to DC bus is continuously updated based on the suggested SOC comparison rule. To verify the method, operation of the algorithm on 4 paralleled battery cells are simulated on Matlab/Simulink. The simulation result shows that the SOCs of paralleled cells are evenly redistributed. It is expected that the proposed algorithm provides high reliable and prolong the life cycle and working capacity of the battery pack.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.31-39
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• 2014

Recently, as Intelligent Transportation System (ITS) and self-driving system become influential in the ground transportation system, automotive radar systems have been actively studied among the various radar systems to implement the vehicle collision detection system and distance measurement system between vehicles. Most of the automotive radars are Frequency Modulated Continuous Wave (FMCW) radar type which can calculate distance and velocity of target by estimating the frequency difference between the transmitted signal and received signal. Therefore, accurate frequency estimation is very important in the FMCW radar system. For this reason, to improve the measurement accuracy of the FMCW radar, Reverse Directional FRI (RD-FRI) Super-Resolution technique which has high frequency estimation accuracy is applied to the FMCW radar system. The feasibility of the proposed technique is evaluated with simulation results and compared with FFT and conventional Super-Resolution techniques. The simulation results show that the proposed technique estimates the frequency with high accuracy and the distance with centimeter accuracy.