• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.135-143
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• 2003

In this study, a real-time simulation model was developed for tracked vehicles with in-arm type semi-active hydro-pneumatic suspension unit using MATLAB S-functions. Since the vehicle model uses relative coordinates and massless link elements, the developed model has an enhanced analytic time performance. Through the comparison of simulation results with multi-body software(DADS), the vehicle model is verified. A controller using on-off skyhook control algorithm is designed with the pilot-centre]led proportional valve based on conventional damper characteristics. Exploiting the developed tracked vehicle model with other subsystem model such as a controller model, a suspension unit model, and a test road model, computer simulations are carried out. Control simulation results with the developed tracked vehicle model show that the semi-active suspension control system has a better performance than the conventional suspension system.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.139-147
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• 2001

2 DOF half-car model with 6 semi-active suspension units is utilized to evaluate the tracked vehicle dynamic performance simulated by several suspension control algorithms. The target of this research is to improve the ride comfort to maintain operator's handling capability when the tracked vehicle travels fast on the rough road. The control algorithms for suspension systems, such as full state feedback active, full state feedback semi-active, sky-hook active, sky-hook semi-active, and on-off systems, are evaluated and analyzed in view point of ride comfort. The dynamic performances of vehicle are expressed and evaluated by vibratory characteristic evaluation curves, performance indices and frequency characteristic curves. The simulation results show that the performances of sky-hook algorithms for ride comfort nearly follow those of full state feedback algorithms and on-off algorithm is recommendatory when the vehicle runs relatively fast.

• Journal of the Korea Institute of Military Science and Technology
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• v.6 no.1
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• pp.9-20
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• 2003

In this study, the performance of a semi-active suspension system for heavy duty tracked vehicles has been investigated. To this end, continuous and on-off Sky-Hook control law have been evaluated for a 1/4 car model. Simulation results show that the semi-active suspension system has potential to improve ride quality of the vehicle. And we proposed a method for improving of variable damper performance.

• International Journal of Automotive Technology
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• v.7 no.4
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• pp.469-475
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• 2006

In this paper, an optimal suspension system with preview of the road input is synthesized for a half tracked vehicle. The main goal of this research is to improve the ride comfort characteristics of a fast moving tracked vehicle in order to maintain the driver's driving capability. Several different kinds of preview control algorithms are evaluated with active or semi-active suspension systems. The road information estimated from the motion of the 1st road-wheel is adequate to make the best use of the preview control algorithm for tracked vehicles. The ride-comfort characteristics of the tracked vehicle are more dependent on pitching angular acceleration than heaving acceleration. The pitching motion is reduced by the suspension system with hard outer suspensions and soft inner suspensions. Simulation results show that the performance of sky-hook algorithms for ride comfort nearly follow that of full state feedback algorithms.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.73-78
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• 2002

Cabbage is one of the most important vegetable in Korea. The cabbage production was mainly based on human labor A comprehensive research fur substituting the human labor by machines has been performed until now. In general, cabbage is cultivated on hillside in Korea. Picking up the harvested cabbages in field and carrying to a vehicle fur transportation are very laborious work. Manual transportation of cabbage is likely to damage the quality and is also a cause to increase the cost of cabbage production. This study was to develop and evaluate a prototype cabbage loader fur efficient and safe transportation of cabbage. The developed loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transportation and loading of cabbage in a steep field. The maximum loading weight of the loader was 1.0 ton. By using two sets of safety devices attached to the loader to avoid the roll-over in a steep field, the static rollover slopes were increased up to 34.0% and 37.4% fur the left and the rear direction, respectively The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The loading capacity of the loader was about 35 pallets/hr when picking up, carrying, and unloading two cabbage pallets for one loading operation. The loading capacity was more than 8 times in comparison with the conventional human labor. The developed loader could be used fur loading and carrying the other vegetables. The study suggested a possible approach for designing the field machines operated on hillside.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.480-488
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• 2000

Cabbage is the most important vegetables in korea. The cabbage production was based on arduous human labor. A comprehensive research for substituting the human work by machines has been performed at present. In general, cabbage is cultivated on hillside in korea. The harvested cabbage in a field and carrying it to a vehicle for transportation are very laborious work. Hand labor in cabbage transportation to the market damages the quality of cabbage and is also a cause to increase the cost of cabbage production. This study was to design and evaluate a prototype cabbage loader for deserving efficient and safe transportation of cabbage. The developed cabbage loader was a semi-tracked vehicle operated by a hydraulic system, allowing the safe transporting and the loading of cabbage in a steep field. The maximum loading capacity of the loader was 1.0 ton. By using safety devices attached to the loader, the static slopes were 34.0% and 37.4% for the left and the rear roll-over, respectively. The maximum field speed was about 6km/hr with two cabbage pallets of 750kg at a 25% inclined field. The field capacity was about 35 pallets/hr in case of picking up, carrying and unloading two cabbage pallets. The field efficiency of the loader was analyzed to be more than 8 times in comparison of the conventional human labor. The developed loader would be applied for loading and carrying the other vegetables due to the similarity of operations. The study suggested a standard approach to the design of field machines operated in a steep field.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.1-11
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• 2014

In this paper we propose a system for vehicle detection and tracking which has the ability to learn on-line appearance changes of vehicles being tracked. The proposed system uses feature-based tracking method to estimate rapidly and robustly the motion of the newly detected vehicles between consecutive frames. Simultaneously, the system trains an online vehicle detector for the tracked vehicles. If the tracker fails, it is re-initialized by the detection of the online vehicle detector. An improved vehicle appearance model update rule is presented to increase a tracking performance and a speed of the proposed system. Performance of the proposed system is evaluated on the dataset acquired on various driving environment. In particular, the experimental results proved that the performance of the vehicle tracking is significantly improved under bad conditions such as entering a tunnel and passing rain.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.543-546
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• 1997

The purpose of this study is to investigate the ERSU(Electr0-Rheological Suspension IJnit) and some progress of damping force characteristic of a ERSU. This paper describes overall construction of th'e system design and the manufacturing of ERSU. A model of the ERSU is made by using electric field dependent on Bingham properities of ER fluid. In this paper. the ERSU is designed and manufactured for a light ground tracked vehicle. From the results, it is shown that the damping performance of ERSLJ is better than that of a passive suspension unit. This experimental study might be very useful for the simulat~on and the design of semi-active suspension units.