Man-Ho Kim

Implementation of a fuzzy-inference-based, low-speed, close-range collision-warning system for urban areas

Traffic accidents are still increasing even though vehicles are becoming more intelligent to enhance driver convenience and safety. Single car-on-car rear impacts in urban areas have increased rapidly due to driver inattention. According to a Road Traffic Authority (ROTA) report in Korea in 2006, 85.2% of single car-on-car rear impact accidents occurred at less than 60 km/h, and 25.3% of the total occurred at between 30 km/h and 50 km/h. To prevent rear vehicle crashes in urban areas, automobile manufacturers have developed various low-speed, close-range collision-warning systems. This paper presents a low-speed, close-range collision-warning algorithm for urban areas using fuzzy inference. Experiments using an embedded microprocessor in the driving track demonstrated the feasibility of the proposed collision-warning system. The results indicate that the fuzzy inference-based, low-speed, close-range collision-warning system could reduce traffic accidents by alerting the driver to potential collisions.

Development of Vision based Control Smart Windwhield Wiper System for Intelligent Vehicle

Windshield wipers play a key role in assuring the drivers safety during precipitation. The traditional wiper systems, however, requires drivers constant attention in adjusting the wiper speed and the intermittent wiper interval because the amount of precipitation on the windshield constantly varies according to time and vehicles speed. Because the manual adjustment of the wiper distracts drivers attention, which maybe a direct cause of traffic accidents, many companies have developed automatic wiper systems using some optical sensors with various levels of success. This paper presents the development of vision-based smart windshield wiper system that can automatically adjust its speed and intermittent interval according to the amount of water drops on the windshield. The system employs various image processing algorithms to detect water drops and fuzzy logic to determine the speed and the interval of the wiper

A Study on Distributed Message Allocation Method of CAN System with Dual Communication Channels

The CAN (Controller Area Network) system is the most dominant protocol for in-vehicle networking system because it provides bounded transmission delay among ECUs (Electronic Control Units) at data rates between 125Kbps and 1Mbps. And, many automotive companies have chosen the CAN protocol for their in-vehicle networking system such as chassis network system because of its excellent communication characteristics. However, the increasing number of ECUs and the need for more intelligent functions such as ADASs (Advanced Driver Assistance Systems) or IVISs (In-Vehicle Information Systems) require a network with more network capacity and the real-time QoS (Quality-of-Service). As one approach to enhancing the network capacity of a CAN system, this paper introduces a CAN system with dual communication channel. And, this paper presents a distributed message allocation method that allocates messages to the more appropriate channel using forecast traffic of each channel. Finally, an experimental testbed using commercial off-the-shelf microcontrollers with two CAN protocol controllers was used to demonstrate the feasibility of the CAN system with dual communication channel using the distributed message allocation method.

Implementation of IEEE 1451 based Dual CAN Module for Fault Tolerance of In-Vehicle Networking System

As many systems depend on electronics in an intelligent vehicle, concern for fault tolerance is growing rapidly. For example, a car with its braking controlled by electronics and no mechanical linkage from brake pedal to calipers of front tires(brake-by-wire system) should be fault tolerant because a failure can come without any warning and its effect is devastating. In general, fault tolerance is usually designed by placing redundant components that duplicate the functions of the original module. In this way a fault can be isolated, and safe operation is guaranteed by replacing the faulty module with its redundant and normal module within a predefined interval. In order to make in-vehicle network fault tolerant, this paper presents the concept and design methodology of an IEEE 1451 based dual CAN module. In addition, feasibility of the dual CAN network was evaluated by implementing the dual CAN module.

Analytical hybrid redundancy system for the fault tolerance of advanced driver assistance systems

The growing dependence on electronic sensors has resulted in increased concerns over the fault tolerance in safety-critical systems. For example, a vehicle with an advanced driver assistance system, which assists safe driving using numerous electronic elements, should be fault tolerant because sensor failures can lead to events in which car occupants receive serious injuries. However, it is often undesirable to have multiple redundant sensors because of the high cost of critical sensors such as the radar in an advanced driver assistance system. To address this problem, we present an analytical hybrid redundancy system that provides fault tolerance using fault detection and exception-handling algorithms. On the basis of the actual range data from an advanced driver assistance system radar, we present the results of numerical simulations of the analytical hybrid redundancy system and show that it outperforms existing approaches with respect to a number of performance indices.

Development of Fuzzy Hybrid Redundancy for Sensor Fault-Tolerant of X-By-Wire System

The dependence of numerous systems on electronic devices is causing rapidly increasing concern over fault tolerance because of safety issues of safety critical system. As an example, a vehicle with electronics-controlled system such as x-by-wire systems, which are replacing rigid mechanical components with dynamically configurable electronic elements, should be fault￢tolerant because a devastating failure could arise without warning. Fault-tolerant systems have been studied in detail, mainly in the field of aeronautics. As an alternative to solve these problems, this paper presents the fuzzy hybrid redundancy system that can remove most erroneous faults with fuzzy fault detection algorithm. In addition, several numerical simulation results are given where the fuzzy hybrid redundancy outperforms with general voting method.

Development of Smart AQS for Commercial Vehicle for Satisfying Agreeable Environment

Recently, many automotive companies tend to apply an air quality system (AQS), which prevents polluted air such as smoke or dust by controlling air intake actuator of vehicle, to satisfy the consumer`s need for agreeable in-vehicle environment. However, performance of the traditional AQS is not satisfactory because a polluted air may enter into the inside of vehicle through the breaks of windows. Especially, the commercial vehicles such as bus or truck need to be prevented polluted air from the breaks of vehicle. Hence, as an alternative to the traditional AQS, this paper presents the architecture of smart AQS for commercial vehicle and implementation of the smart AQS. Also, the performance of the suggested system is evaluated through an experimental testbed.

Development of Kalman Hybrid Redundancy for Sensor Fault-Tolerant of Safety Critical System

As many systems depend on electronics, concern for fault tolerance is growing rapidly in the safety critical system such as intelligent vehicle. In order to make system fault tolerant, there has been a body of research mainly from aerospace field including predictive hybrid redundancy by Lee. Although the predictive hybrid redundancy has the fault tolerant mechanism to satisfy the fault tolerant requirement of safety crucial system such as x-by-wire system, it suffers form the variability of prediction performance according to the input feature of system. As an alternative to the prediction method of predictive hybrid redundancy for robust fault tolerant, Kalman prediction has attracted some attention because of its well-known and often-used with its structure called Kalman hybrid redundancy. In addition, several numerical simulation results are given where the Kalman hybrid redundancy outperforms with predictive smoothing voter.

Implementation of TTP Network System for Distributed Real-time Control Systems

Recently, many ECUs(Electronic Control Units) have been used to enhance the vehicle safety, which leads to a distributed real-time control system. The distributed real-time control system requires to reduce the network delay for dependable real-time performance. There are two different paradigms by which a network protocol operates: event-triggered and time-triggered. This paper focuses on implementation of a time-triggered protocol. i.e. TTP/C(Time-Triggered Protocol/class C). This paper presents a design method of TTP control network and performance evaluation of distributed real-time control system using TTP protocol.

Performance Evaluation of Fault Tolerant Switched Ethernet Architecture for Railway Signal System

In high reliability systems for industrial network such as railway signal system, fieldbus protocols have been known to satisfy the real-time and fault tolerant requirements. But, the application of fieldbus has been limited due to the high cost of hardware and software, and the difficulty in interfacing with multi-vendor products. Therefore, as an alternative to fieldbus, the computer network technology, especially Ethernet(IEEE 802.3), is being adapted to the industrial network. In this paper, we propose a switched Ethernet based railway signal system because of its very promising prospect for industrial application due to the elimination of uncertainties in the network operation. In addition, we propose the redundancy architecture for the reliability of network components. More specifically, this paper presents an analytical performance evaluation of switched Ethernet for railway signal system, and shows experimental evaluation of redundancy architecture.