• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.513-520
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• 2011

This paper presents the motion planning of robotic vehicles for the path tracking and the obstacle avoidance. To follow the given path, the vehicle moves through the turning radius obtained through the pure pursuit method, which is a geometric path tracking method. In this paper, we assume that the vehicle is equipped with a 2D laser scanner, allowing it to avoid obstacles within its sensing range. The turning radius for avoiding the obstacle, which is inversely proportional to the virtual force, is then calculated. Therefore, these two kinds of the turning radius are used to generate the steering angle for the front wheel of the vehicle. And the vehicle reduces the velocity when it meets the obstacle or the large steering angle using the potentials of obstacle points and the steering angle. Thus the motion planning of the vehicle is done by planning the steering angle for the front wheels and the velocity. Finally, the performance of the proposed method is tested through simulation.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.773-784
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• 2023

In this study, we developed a dynamic model and steering controller model for an autonomous tractor and evaluated their performance. The traction force was measured using a 6-component load cell, and the rotational speed of the wheels was monitored using proximity sensors installed on the axles. Torque sensors were employed to measure the axle torque. The PI (proportional integral) controller's coefficients were determined using the trial-error method. The coefficient of the P varied in the range of 0.1 - 0.5 and the I coefficient was determined in 3 increments of 0.01, 0.05, and 0.1. To validate the simulation model, we conducted RMS (root mean square) comparisons between the measured data of axle torque and the simulation results. The performance of the steering controller model was evaluated by analyzing the damping ratio calculated with the first and second overshoots. The average front and rear axle torque ranged from 3.29 - 3.44 and 6.98 - 7.41 kNm, respectively. The average rotational speed of the wheel ranged from 29.21 - 30.55 rpm at the front, and from 21.46 - 21.63 rpm at the rear. The steering controller model exhibited the most stable control performance when the coefficients of P and I were set at 0.5 and 0.01, respectively. The RMS analysis of the axle torque results indicated that the left and right wheel errors were approximately 1.52% and 2.61% (at front) and 7.45% and 7.28% (at rear), respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.133-139
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• 2008

In this paper, the feasibility for producing a plastic optical fiber sensor to be used as an anti-drowsy driving sensor is discussed. This sensor consists of a plastic optical fiber wound on the steering wheel covered by soft material. When a driver hold a steering wheel, the gripping force is induced and causes to the bend of the plastic optical fiber which decreases the power of light propagated inside the plastic fiber. The experimental results show that the detected optical power decrease as the gripping force increase and that this sensor can be used as the anti-drowsy driving sensor.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.6
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• pp.269-279
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• 2020

This paper presents the design and implementation of embedded systems and autonomous path generation for autonomous speed sprayer. Autonomous Orchard Systems can be divided into embedded controller and path generation module. Embedded controller receives analog sensor data, on/off switch data and control linear actuator, break, clutch and steering module. In path generation part, we get 3D cloud point using Velodyne VLP16 LIDAR sensor and process the point cloud to generate maps, do localization, generate driving path. Then, it finally generates velocity and rotation angle in real time, and sends the data to embedded controller. Embedded controller controls steering wheel based on the received data. The developed autonomous speed sprayer is verified in test-bed with apple tree-shaped artworks.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.731-738
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• 2013

This paper describes a fault-tolerant driving control strategy for an independent steer-by-wire system in sixwheel-drive/six-wheel-steering vehicles. An algorithm has been designed to realize vehicle maneuverability that is as close as possible to that of non-faulty vehicles by inducing high slip ratio of the wheel through a faulty steer-by-wire system in order to reduce the lateral tire force, which is resistant to the yaw motion. Considering the transition of the longitudinal tire force of a wheel with a faulty steer-by-wire component, the longitudinal tire forces are optimally distributed to the other wheels. Fault-tolerant driving performance has been investigated via computer simulations. Simulation studies show that the proposed algorithm can significantly improve the maneuverability of a vehicle with a faulty steer-by-wire system as compared to the optimal traction distribution method.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.558-565
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• 2011

Various robot platforms have been designed and developed to perform given tasks in a hazardous environment for surveillance, reconnaissance, search and rescue, etc. We considered a terrain-adaptive and transformable hybrid robot platform that is equipped with rapid navigation capability on flat floors and good performance in overcoming stairs or obstacles. The navigation mode transition is determined and implemented by adaptive driving mode control of the mobile robot. In order to maximize the usability of wheel-track hybrid robot platform, we propose a terrain-adaptive and user-friendly remote controller and verify the efficiency and performance through its navigation performance experiments in real and test-bed environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.6
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• pp.34-42
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• 2006

As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires(steer-by-wire) should be fault tolerant because a failure can come without any warning and its effect is devastating. In order to make system fault tolerant, there has been a body of research mainly from aerospace field. This paper presents the structure of predictive smoothing voter that can filter out most erroneous values and noise. In addition, several numerical simulation results are given where the predictive smoothing voter outperforms well-known average and median voters.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.160-165
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• 1998

In this paper, We discuss the directional stability of a Mini-bus with varying suspension design parameters. We analyzed the vehicle behavior during the cornering in a transient steering condition. We made a vehicle model by use of DADS, which is dynamic analysis software, in order to carry out many cases of simulation with varying design parameters. The effect of toe-geometry change to vehicle stability is evaluated by computer simulation and the actual test. In order to reduce the under steer characteristics of a mini-bus, the amount of toe geometry change should be less than current value.

• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.126-134
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• 2008

As many systems depend on electronics, concern for fault tolerance is growing rapidly. For example, a car with its steering controlled by electronics and no mechanical linkage from steering wheel to front tires (steer-by-wire) should be fault tolerant because a failure can come without any warning and its effect is devastating. In order to make system fault tolerant, there has been a body of research mainly from aerospace field. This paper presents the structure of predictive hybrid redundancy that can remove most erroneous values. In addition, several numerical simulation results are given where the predictive hybrid redundancy outperforms wellknown average and median voters.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.6
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• pp.37-45
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• 1987

최근의 경량화 췌ㅅ로 말미암아 승용차의 차체는 박판일체식 구조로 제작되어 구조적 강성의 약화를 가져 왔으며 이로 인하여 외부의 요인으로부터 발생되는 승용차의 진동문제는 더욱 악화되고 해결하기 어렵게 되어가고 있다. 이 논문에서는 이러한 여러가지 문제로 인하여 전륜구동형 승용차의 조향계에서 발생되는 Shake와 Shimmy를 2-모드 동흡진기를 사용하여 제어하고자 하며 실제적으로 시작품을 제작하여 실차상태에서 확인시험을 실시하였다.