• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.144-151
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• 2008

The bi-modal vehicle is composed of two car-bodies and three axles. Each axle of the vehicle has an independent suspension and all wheels are steerable. Since the bi-modal vehicle has longer wheelbase than most urban buses, the All-Wheel-Steering(AWS) system is adapted for to ensure safe driving and proper turning radius on a curved road. This paper proposes an AWS control algorithm for stable driving of bi-modal vehicle. Steering angles and directions of each axle of bi-modal vehicle changed according to the driving environment and steering modes. In the case that front and rear axles should be steered in opposite directions is a negative mode, and the other case that the axles should be steered in the same direction is a positive mode. For example, in the positive mode, front and real axles are steered in the same direction, while in the negative mode, they are steered in the opposite direction. A multibody model of the vehicle is used to verify the performance of the steering algorithm and simulation results of 2WS are compared with those of AWS under the same condition.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.979-983
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• 2008

A bi-modal tram can travel in not only dedicated way but also road so as to reduce construction costs and increase vehicle operation efficiency, whose passenger capacity is 2,500 to 7,000 persons/direction/hour. A bi-modal has an electronic guidance system that knows the location and route of the vehicle, and uses magnetic markers in the road surface for reference. Since a bi-modal tram will be operated in the downtown area, there is some possibility that strong wind occurred between high-rise buildings can produce sudden lateral movement (displacement) of the vehicle to influence its automatic operation controlled by electronic guidance system. For bi-modal tram in the automatic operation mode, lateral movements occurred by strong wind were calculated and analyzed in the dynamic model developed by using the ADAMS. Some useful relations among vehicle speeds, wind speeds, and lateral behaviors were discussed in this paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.829-830
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• 2007

• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.444-450
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• 2007

The bi-modal tram guided by the magnetic guidance system has two car-bodies and three axles. Each axle of the vehicle has an independent suspension to lower the floor of the car and improve ride quality. The turning radius of the vehicle may increase as a consequence of the long wheel base. Therefore, the vehicle is equipped with the All-Wheel-Steering(AWS) system for safe driving on a curved road. Front and rear axles should be steered in opposite directions, which means a negative mode, to minimize the turning radius. On the other hand, they also should be steered in the same direction, which means a positive mode, for the stopping mode. Moreover, only the front axle is steered for stability of the vehicle upon high-speed driving. In summary, steering angles and directions of the each axle should be changed according to the driving environment and steering mode. This paper proposes an appropriate AWS control algorithm for stable driving of the bi-modal tram. Furthermore, a multi-body model of the vehicle is simulated to verify the suitability of the algorithm. This model can also analyze the different dynamic characteristics between 2WS and AWS.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.229-238
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• 2009

In this paper, AWS ECU test method, which is considering behavior of a Bi-modal tram, is described. In order to evaluate the performance of an electronic automotive ECU, the method which combines HILS (Hardware In the Loop Simulation) and RBT (Requirement Based Testing) is introduced. HILS is the method to predict the behavior of a vehicle adopting an ECU. The behavior of a Bi-modal tram can be analyzed by using the vehicle dynamic model. Requirement Based Testing compare the outputs of a real system with a virtual electronic unit (oracle) which created by the requirements. Rear axles of the Bi-modal tram are independently controlled by two AWS ECU. Especially, swing out can happen when an articulated vehicle is operated in the curved road. Therefore dynamic behaviour of a Bi-modal tram is considered at this situation. Through this study, the reliability of ECU can be verified economically and safely using the proposed test method before conducting the track test.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1717-1725
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• 2008

In this paper, the HILS system is proposed for the AWS ECU of the bi-modal tram. Using the HILS of the AWS ECU, the behavior of the vehicle can be predicted and the reliability of the AWS system also can be verified. The hardware part of the HILS system includes the ECUs, hydraulic systems, steering linkages and sensors of the bi-modal tram. The software part of the HILS system contains the virtual vehicle model and sensor emulation. Driver input conditions, such as vehicle velocity and front steering angle, are provided to the ECUs by the software. The driving simulation of the bi-modal tram is carried out by the HILS. Also, the reliability of the AWS system, including the ECUs and hydraulic systems, is verified.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2297-2302
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• 2010

The status and effectiveness of Bi-modal Tram is analyzed through the comparison of the transport effectiveness and operation cost between the public transportation systems (bus, light rail transit) considering the vehicle and operation characteristic of new transit system Bi-modal Tram. The standard operation schedule is established in consideration of the vehicle specification and operation characteristic of main public transportation modes, and then the annual average operation cost is estimated depending on the volume, speed, analysis length for respective public transportation mode. Through analyzing the operation cost and distribution characteristic of public transportation modes depending on the transport volume and travel speed, the operational efficiency suitable for the city is derived. It is concluded that the operational efficiency of Bi-modal Tram is superior to that of the bus and light rail transit on the aspect of travel volume and operation speed.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.5
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• pp.84-90
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• 2009

The bi-modal tram is under development as a new public transportation. The features of the tram are an extended wheel base and its length. This features result in difficulties for drivers on maneuvering the tram. Therefore, the all wheel steering system is applied to the articulated vehicle. The AWS system enables the vehicle to steer all the rear wheels independently and improves its driving characteristics. However, the bi-modal tram has a problem to move backward in the limited place because of its geometric feature and the AWS system. Hence, the reverse parking assistant algorithm for articulated vehicle is developed to solve the problems of the reverse parking. Using the vehicle model which includes the reverse parking assistant algorithm, the dynamic analysis is performed for several parking cases. By the result of the analysis, the stability and validity of the reverse parking assistant algorithm is verified.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.99-108
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• 2007

The bi-modal tram guided by the magnetic guidance system has two car-bodies and three axles. Each axle of the vehicle has an independent suspension to lower the floor of the car and improve ride quality. The turning radius of the vehicle may increase as a consequence of the long wheel base. Therefore, the vehicle is equipped with the All-Wheel-Steering(AWS) system for safe driving on a curved road. Front and rear axles should be steered in opposite directions, which means a negative mode, to minimize the turning radius. On the other hand, they also should be steered in the same direction, which means a positive mode, for the stopping mode. Moreover, only the front axle is steered for stability of the vehicle upon high-speed driving. In summary, steering angles and directions of the each axle should be changed according to the driving environment and steering mode. This paper proposes an appropriate AWS control algorithm for stable driving of the bi-modal tram. Furthermore, a multi-body model of the vehicle is simulated to verify the suitability of the algorithm. This model can also analyze the different dynamic characteristics between 2WS and AWS.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.777-778
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• 2009