• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.20-20
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• 2017

궤도형 차량의 이동구조는 에너지 소비 측면에서 단점이 있지만 접지압의 감소로 인한 평지 및 야지험지에서도 원활한 주행이 가능한 장점으로 인해 농업분야의 플랫폼에서 많이 사용된다. 곡식을 베는 일과 탈곡하는 일을 한 번에 하는 콤바인도 이러한 무한궤도형 이동구조를 사용한다. 또한 궤도형 차량의 방향전환 및 주행속도 변환은 좌 우 궤도의 회전 속도를 다르게 하여 동시에 제어하기 때문에 정교한 주행 성능을 위해서는 궤도형 차량의 기구학 모델을 고려한 경로 계획이 필요하다. 본 연구에서는 직교형 포장에서 Round harvesting 기법 기반으로 궤도형 차량의 기구학 모델 및 포장정보를 고려한 자율주행 콤바인 경로계획 알고리즘을 개발하고자 하였다. 이를 위해 Labview 기반의 궤도형 차량 시뮬레이션을 구축하여 실제 포장정보를 이용해 생성 된 경로의 적용 가능성을 구명하고자 하였다. 자율주행 콤바인 경로 계획은 콤바인의 길이, 너비, 회전 시 좌 우 궤도의 속도 비, 직진 속도와 회전 속도 비, 회전 각도, 포장의 외부 경계선, 작업 겹침 량, 회경 횟수를 이용하여 좌현 새머리 선회를 포함한 내부 왕복작업 경로를 생성하며 외부 회경 횟수는 2~3회를 가정하였다. 자율주행 시뮬레이션은 차체와 궤도 자체의 미끄러짐과 작동기 지연시간을 단순화 한 궤도형 기구학 모델형태로 구성하였다. 추종 알고리즘은 선견 거리법을 사용하였으며, 측면 변이값과 방향 오차의 선형조합을 이용하여 조향변수를 정의하고 퍼지로직기반으로 좌 우 궤도 속도를 7 단계화하여 조향장치를 모델링하였다. 실험결과 개발 된 경로생성 알고리즘은 실제 취득 된 포장 외부 경계 GPS 위 경도를 이용해 자동으로 생성이 가능하며 간략화 된 콤바인 시뮬레이션에서 직진주행 RMS 위치 오차는 0.05 m, 선회구간에서 직진 구간 진입 시 RMS 위치 오차는 0.11 m, 직진 구간 RMSE 방향 오차는 3.2 deg로 콤바인 예취부 간격인 30 cm보다 작은 위치 오차를 보이며 생성된 경로 전체 추종이 가능함을 나타내었다.

• Ocean and Polar Research
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• v.26 no.2
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• pp.333-339
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• 2004

This paper is concerned with an experimental investigation about tractive performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of $0.9\;m(L)\;{\times}\;0.75\;m(B)\;{\times}\;0.4\;m(H)$ and the weight of 167 kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of $6.0\;m(L)\;{\times}\;3.7\;m(B)\;{\times}\;0.7\;m(H)$. Slip of vehicle and driving torque of motor were measured with respect to experimental variables; grouser span, grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. $L_8$ orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables on traction performance are evaluated.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.37-42
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• 2006

This paper is concerned with experimental investigation of steering performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of 0.9 m(L)x0.75 m(B)x0.4 m(H) and weight of 167 kg was constructed with a pair of driving chain links, driven by two AC-servo motors. The tracks were configured with detachable grousers with variable span. A deep seabed was simulated by means of a bentonite-water mixture in a soil bin of 6.0 m(L)x3.7 m(B)x0.7 m(H). The turning radii of vehicle and driving torques of motors were measured with respect to experiment variables: steering ratio, driving speed, grouser chevron angle, grouser span, and grouser height. L8 orthogonal table is adopted for DOE (Design of experiment). The effects of experiment variables on steering performance are evaluated.

• Journal of Ocean Engineering and Technology
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• v.21 no.1 s.74
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• pp.75-80
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• 2007

Measuring the ground speed and the rotation speeds of tracks is an easy and realistic method to detect the track slips. It is very advantageous if the slips can be measured and applied to real time control of the vehicle. With a proper speed, the tractive force of a tracked vehicle may be calculated from the vehicle dynamics. For the control of tracked vehicle, the relationship between the slip and the tractive force is necessary. In this paper, a series of drawbar-pull tests, in which slips of two tracks are measured under the variational draw-bar weight, is executed to directly obtain the slip-tractive force relationship. For the purpose of the test, a tractive vehicle model was manufactured, and an artificial soil was simulated by using a bentonite-water mixture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1611-1619
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• 2015

This study examined the toughness improvement of a track shoe used as the undercarriage of excavator and bulldozer parts. The excavator is operated under poor conditions, such as the build-up field and quarry. Therefore, the track shoe requires high strength and impact toughness to endure immense shock while at work. The track shoe was made of heat treated boron steel. The sufficient possibility of hardenability with the theoretical Jominy curve for boron steel was confirmed while quenching. The Taguchi orthogonal array experiment method was used to optimize the process variables, such as area reduction ratio and heat treatment conditions (tempering temperature and holding time), to achieve toughness improvement. The toughness of the track shoe increased with increasing area reduction, and a tempering temperature of $210^{\circ}C$ and a tempering time of 80 min are beneficial for improving the toughness of the track shoe.

• Ocean and Polar Research
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• v.26 no.2
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• pp.323-332
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• 2004

This paper concerns about a study on dynamic responses of tracked vehicle on soft cohesive soil. For dynamic analyses of tracked vehicle, two different models were adopted, i.e. a single-body model and a multi-body model. The single-body vehicle model was assumed as a rigid body with 6-dof. The multi-body vehicle was modeled by using a commercial software, RecurDyn-LM. For the both models properties of cohesive soft soil were modeled by means of three relationships: pressure to sinkage, shear displacement to shear stress, and shear displacement to dynamic sinkage. Traveling performances of the two tracked vehicle models were compared through dynamic analyses in time domain.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2393-2395
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• 2001

The mobile robot is used as an instrument of transportation in automated plant. But the greater part of the moving method is the wheel-type. The wheel-type robot is easier control than the track-type, However the track-type is better than the wheel-type in bad landform(bend landform, an incline plane, stairs). In this paper, we propose the navigation algorithm of track-type robot in order to improve a defect of wheel-type. We experiment in bend landfrom and even ground to differentiate the navigation method. To estimate robot pose, we use the 80196 in a close distance and the vision-board in a long distance. Each data is managed in main PC and then the part of managing correspond to every sensor. We also use twelve supersonic wave-sensors to recognize external surroundings. As the result of experiment, we analyze the algorithm of control and make possible surroundings-adaptation.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.5
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• pp.1135-1144
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• 2018

An electric wheelchair used to be utilized as a piece of equipment for the disabled and the elderly in the past, but the recent changes to its functions and forms have made it available across various fields and purposes. In this paper, we propose a continuous track type of electric wheelchair prototype to be used in various fields and environments and a monitoring system to control it. A frame stress design was applied to improve its stability during driving compared with the previous wheelchairs. In addition, we provide a convenience for free and easy operation of them using the App. based on android. A monitoring system based on C# was also added to control a large number of electric wheelchairs. As a result of the implementation and performance evaluation, the von Mises stress value was measured 4.401% within the normal range through five times of stress interpretations, and its accuracy of communication for system manipulation was recorded about 98.75%, which means that it has been proven to be safer than the previous wheelchairs.

• Korean Management Science Review
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• v.11 no.1
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• pp.117-128
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• 1994

This paper describes a case study on the analysis of RAM(Reliability, Availability, and Maintainability) factors obtained from the Endurance-Test for a military full-tracked armored vehicle. In analysing RAM factors of the vehicle we used such a statistical technique as method of Maximum-Likelihood for estimating parameters.

• Korean Journal of Construction Engineering and Management
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• v.13 no.6
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• pp.121-132
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• 2012

The current estimation system of construction equipment cost was first introduced in 1960's when general contractors had ownership of equipment. However, most of construction equipment in construction sites has been rented from equipment leasing company these days. Therefore, the improvement of current cost estimation system is therefore inevitable in order to advance domestic construction industry. This study is aimed to suggest the improved system by analyzing nationwide market rental rates of major construction equipment. A user friendly prototype of actual database grounded on actual market rental rates collected from over 200 leasing companies in the nation was proposed. The database includes various rates and statistics analyzed by different form of contract as well as different region. Using the collected data, "The Cost Estimate System in Construction Equipment Database" was developed by using VBA(Visual Basic for Applications). The system makes users convenient to utilize the rental rates by choosing equipment and region, and various types of contract.