• 한국자동차공학회논문집
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• 제10권4호
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• pp.166-174
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• 2002

Power steering systems far automobile are becoming ever more popular because they reduce steering efforts of the drivers, especially during parking lot maneuver. In this paper, the controller of the motor driven hydraulic power steering(MDHPS) has been designed and developed. This system uses a power source of DC motor instead of engine power source for power steering drive oil pump. The developed MDHPS system is accomplished a highly sensitive power steering resulted from electronic control under variable driving condition. Furthermore, this system is more improvement than type of engine driving far fuel economy.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.119-124
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• 2006

This paper deals with energy-saving effort in the hydraulic power steering system. Commonly, the hydraulic power steering systems are used for passenger cars and the reduction of pumping loss under non-steering condition is important to improve fuel economy. Experiments and simulations are performed simultaneously to examine the main factors to reduce the pumping loss-pressure loss and flow rate of the power steering systems. Fuel economy effect of the optimal design of power steering system is verified by vehicle test - more than 1% fuel consuming reduction is attained.

• 농업과학연구
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• 제38권1호
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• pp.121-128
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• 2011

I/An electro-hydraulic transmission having advantages of convenience, safety, simple linking and high power, and an electronic control system were designed and fabricated. In this study, characteristics of the control system were investigated through outdoor tests for evaluation of installation of the system on a combine. Major findings were as followings. 1. Experiment for performance evaluation of the control system was conducted on concrete road. With steering lever in neutral position, driving HST swash plate and left/right wheel speed increased in proportion to driving lever angle. In case of steering control, steering swash plate angle changed in proportion to steering lever angle. This should cause increase in outer wheel speed, but it was observed that HST swash plate was controlled toward neutral to maintain the speed before steering. As a result, speed before steering was maintained despite the change in outer wheel speed by steering HST swash plate angle change. 2. It was observed that the HST system enabled steering with outer wheel maintained at constant speeds while inner wheel speed decreased, which was more stable than conventional mechanical links. In addition, for the selected 5 criteria, experiment showed satisfactory results and it was judged that installation on real vehicle would be feasible. 3. The control system showed response property of appropriate forward/reverse movement and lift/right steering, without causing any problems during experiment on concrete. Result of response property experiment on field operation also showed appropriate control over forward/reverse movement and left/right steering.

• 한국생산제조학회지
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• 제4권2호
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• pp.12-17
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• 1995

The operation of heavy tracked vehicle has the problems in the steering that made by misoperations. The protection device is applied to the vehicles. But that device is applied to the vehicles. But that device has the engine stop and over load condition problems. the steering safety system is developed on the basis of clutch slip that proved the durability in the dynamo test and field test. The steering safety system caused the performance improvement of vehicles when steering.

• 제어로봇시스템학회논문지
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• 제21권2호
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• pp.95-101
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• 2015

In this paper, we develop a sliding mode control for steering wheel angle control based on torque overlay in order to resolve the problem of previous methods for Electric Power Steering (EPS) systems in the Lane Keeping System (LKS) of autonomous vehicles. For the controller design, we propose a 2nd order model of the electric power steering system in an autonomous LKS. The desired state model is designed to prevent a rapid change of the steering wheel angle. The sliding mode steering wheel angle controller is developed for the robustness of the disturbance. Since the proposed method is designed based on torque overlay, torque integration with basic functions of the EPS system for the steering wheel angle control is available for the driver's convenience. The performance of the proposed method was validated via experiments.

• 한국자동차공학회논문집
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• 제22권6호
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• pp.113-119
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• 2014

For the robust design of Motor Driven Power Steering (MDPS) systems, it is important to consider energy efficiency from every aspect such as system configuration and current flow, etc. If design optimization is not considered, it has many problems on a vehicle. For example, when evaluating steering test, particularly the Catch-up test which turning the steering wheel left or right quickly, steering effort should be increased rapidly. Also a vehicle might have poor fuel efficiency. In this study, it is calculated energy consumption for each component of the steering system and analyzed factors of energy consumption. As a result, this paper redefines a method to estimate steering input torque using characteristics of vehicle electric components and then conducts an analysis of contribution for the Catch-up.

• 한국자동차공학회논문집
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• 제25권2호
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• pp.227-235
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• 2017

In this paper, a systematic 5-mode(road steering, all-wheel steering, crab steering, reduced swing out mode and independent steering) steering algorithm design process for an all-terrain mobile crane with 5 axles and all steerable wheels is proposed. Steering angles for each steering mode are designed based not only on basic theory but also on vehicle specification, design limitation and requirements. A multi-body dynamic analysis is carried out to investigate the feasibility of the steering algorithm. According to the results, the proposed steering algorithm meets the objective of each steering mode.

• Journal of Positioning, Navigation, and Timing
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• 제2권2호
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• pp.123-130
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• 2013

Autonomous agricultural machines that are operated in small-scale farmland frequently experience turning and changes in direction. Thus, unlike when they are operated in large-scale farmland, the steering control systems need to be controlled precisely so that travel errors can be minimized. This study aims to develop a control algorithm for improving the path tracking performance of a steering system by analyzing the effect of the setting of the waypoint, which serves as the reference point for steering when an autonomous agricultural machine moves along a path or a coordinate, on control errors. A simulation was performed by modeling a 26-hp tractor steering system and by applying the equations of motion of a tractor, with the use of a computer. Path tracking errors could be reduced using an algorithm which sets the waypoint for steering on a travel path depending on the radius of curvature of the path and which then controls the speed and steering angle of the vehicle, rather than by changing the steering speed or steering ratio which are dependent on mechanical performance.

• 전기학회논문지
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• 제61권5호
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• pp.735-743
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• 2012

In this paper, we present model predictive control (MPC) applied to lane keeping system (LKS) based on a vision module. Due to a slow sampling rate of the vision system, the conventional LKS using single rate control may result in uncomfortable steering control rate in a high vehicle speed. By applying MPC using multi-rate Kalman filter to active steering control, the proposed MPC-based active steering control system prevents undesirable saturated steering control command. The effectiveness of the MPC is validated by simulations for the LKS equipped with a camera module having a slow sampling rate on the curved lane with the minimum radius of 250[m] at a vehicle speed of 30[m/s].

• 한국공작기계학회논문집
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• 제14권3호
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• pp.110-115
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• 2005

Driving performance is affected by a steering mechanism and characteristics of the ground at off-road skateboarding. In order to drive on off-road, it is necessary off-road wheel and high performance steering mechanism to adapt on various configuration of the ground. In this paper, design factors are studied to affect to steering radius such as inclination angle of a king-bolt, distance of a wheel axle, and rolling angle of a deck plate. A steering system is adhered to inclination face of the deck plate. And, inclination angle is existed between the king-bolt and the flat face of the deck plate. Therefore, the wheel axle of the steering system can be steered by control of the rolling angle of the deck plate.