• Journal of Power System Engineering
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• v.15 no.6
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• pp.86-94
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• 2011

In this paper, an electro hydraulic power steering system based on electro hydrostatic actuator (EHA) is proposed. A detailed steering model for the proposed electro hydraulic power steering system including mechanical and hydraulic subsystems is established. A conventional electro hydraulic power steering system is also modeled to evaluate the performance of the proposed power steering system such as responsiveness, assist force, command tracking and steering feel by computer simulation. From the computer simulation results, it is found that the proposed power steering system based on EHA has desirable performance.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.301-305
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• 2007

The performance of the railway bogie is classified into the stability and the steering performance. Testing for the bogie stability is conducted on the roller rig. But testing for the bogie steering performance on test facility is very difficult, so the testing for the vehicle curving performance is conducted on the real curve track. And it is desirable to test on the full scale test rig, but it caused many problems relating to test costs, test time. To overcome these problems, the small scale test rig is actively used in the field of bogie stability. Thus, in this paper, we have studied the scale track to test the bogie steering performance. For this, we designed the 1/5 scale test track equivalent to radius 200 curve and confirmed the validity of the testing for the bogie steering performance on the scale curve track through the testing using 1/5 scale bogie.

• Journal of Drive and Control
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• v.14 no.2
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• pp.9-15
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• 2017

The steering systems of all-terrain cranes have been developed with various control strategies for the stability and drivability. To optimally control the input steering angle, an accurate mathematical model that represents the actual crane dynamics is required. The derivation of an accurate mathematical model to optimally control the steering angle, however, is difficult since the steering-control strategy generally varies with the magnitude of the crane's longitudinal velocity, and the postures of the crane's working parts vary while it is being driven. To address this problem, this paper proposes an automatic steering-control algorithm that is based on the MPC (model predictive control) with a disturbance observer for all-terrain cranes. The designed disturbance observer of this study was used to estimate the error between the base steering model and the actual crane. A model predictive controller was used for the computation of the optimal steering angle, along with the use of the base steering model with an estimated uncertainty. Performance evaluations of the designed control algorithms were conducted based on a curved-path scenario in the Matlab/Simulink environment. The performance-evaluation results show a sound reference-path-tracking performance despite the large uncertainties.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.37-43
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• 2005

A haptic steering system which reflects steering reaction torque has been developed for a fixed base vehicle simulator. The haptic steering system consists of a steering effort sensor, MR-clutch, AC servo motor and controller. In order to generate realistic steering torque feel to driver and at the same time to meet real-time simulation requirement, 3D torque map is constructed by experimental data and torque generation algorithm using the torque map has been also developed. 3D torque map is constructed using curve fitting and interpolation of the measured values of the steering angle, velocity and steering torque from actual slalom test on the proving ground. In order to carry out performance test of the developed haptic steering system, a fixed based vehicle simulator is constructed by integrating real time vehicle dynamics module, VR-video/audio module, and the haptic steering system. Steering torque and steering angle curves have been obtained from virtual testing in the vehicle simulator and performance of the haptic steering system has been evaluated.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.45-55
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• 2013

With the recent advancement of control method and battery technology, the electric vehicle have been researched to replace the conventional vehicle with electric vehicle with the view point of the environmental concerns and energy conservation. An electric vehicle which is equipped with the independent front steering system and in-wheel motors has advantage in terms of control. For example, the different torque which generated by left and right wheels directly can make yaw moment and the independent steering using outer wheel control is able to reduce the sideslip angle. Using of independent steering and driving system, the 4 wheel electric vehicle can improve a performance better than conventional vehicle. In this paper, we consider the method for improving the cornering performance of independent front steering system and in-wheel motor used electric vehicle with the compensated outer wheel angle and direct yaw moment control. Simulation results show that the method can improve the cornering performance of 4 wheel electric vehicle. We also apply the steering motor failure to steer the vehicle turned by the torque difference without steering. This paper describes an independent front steering and driving, consist of three parts; Vehicle Model, Control Algorithm for independent steering and driving and simulation. First, vehicle model is application of TruckSim software for independent front steering and 4 wheel driving. Second, control algorithm describes the reduced sideslip and direct yaw moment method in view of cornering performance. Last is simulation and verification.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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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.

• Journal of Drive and Control
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• v.12 no.3
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• pp.36-43
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• 2015

An autonomous vehicle control algorithm based on Ackerman Geometry is known to be reliable in low tire slip situation. However, vehicles at high speed make lateral errors due to high tire slip. In this paper, considering the tire slip of vehicles, the steering angle is determined based on the Ackerman Geometry and is supplemented tire slip angle by the Stanley steering algorithm. In addition, to prevent the tire slip, the algorithm, which restricts steering if a certain level of slip occurs, is used to reduce the lateral error. While many studies have been extended to include vehicle slip, studies also need to be carried out on the tire slip depending on hardware performance. The control algorithm of autonomous vehicles is compensated considering the sensor noise and the performance of steering actuator. Through the various simulations, it was found that the performance of steering actuator was the key factor affecting the performance of autonomous driving. Also, it was verified that the usefulness of steering algorithm considering the tire slip and performance of steering actuator.

• Journal of Drive and Control
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• v.14 no.2
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• pp.30-36
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• 2017

This paper presents a sliding mode observer-based fault detection algorithm for steering inputs of an all-terrain crane. All-terrain cranes with multi-axles have several steering modes for various working purposes. Since steering angles at the other axles except the first wheel are controlled by using the information of steering angle at the first wheel, a reliable signal of the first axle's steering angle should be secured for the driving safety of cranes. For the fault detection of steering input signal, a simplified crane model-based sliding mode observer has been used. Using a sliding mode observer with an equivalent output injection signal that represents an actual fault signal, a fault signal in steering input was reconstructed. The road steering mode of the crane's steering system was used to conduct performance evaluations of a proposed algorithm, and an arbitrary fault signal was applied to the steering angle at the first wheel. Since the road steering mode has different steering strategies according to different speed intervals, performance evaluations were conducted based on the curved path scenario with various speed conditions. The design of algorithms and performance evaluations were conducted on Matlab/Simulink environment, and evaluation results reveal that the proposed algorithm is capable of detecting and reconstructing a fault signal reasonably well.

• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.27-32
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• 2020

This paper presents steering system requirements to ensure the stabilized lateral control of autonomous driving vehicles. The two main objectives of a lateral controller in autonomous vehicles are maintenance of vehicle stability and tracking of the desired path. Even if the desired steering angle is immediately determined by the upper level controller, the overall controller performance is greatly influenced by the specification of steering system actuators. Since one of the major inescapable traits that affects controller performance is the time delay of the steering actuator, our work is mainly focused on finding adequate parameters of high level control algorithm to compensate these response characteristics and guarantee vehicle stability. Actual vehicle steering angle response was obtained with Electric Power Steering (EPS) actuator test subject to various longitudinal velocity. Steering input and output response analysis was performed via MATLAB system identification toolbox. The use of system identification is advantageous since the transfer function of the system is conveniently obtained compared with methods that require actual mathematical modeling of the system. Simulation results of full vehicle model suggest that the obtained tuning parameter yields reduced oscillation and lateral error compared with other cases, thus enhancing path tracking performance.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.48-55
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• 2010

We have development the steering angle sensor using not only detecting parts but also integrating technique with semiconductors for automobile applications. The performance design and analysis of the steering angle sensor for intelligent vehicles is complicated due to variety of parameters. In this study, the performance characteristics of the angle sensor were analyzed using test rig. By means of magnetic induction technique, these new the steering angle sensors showed excellent magnetic characteristics. The detection range of steering angle sensor obtained was ${\pm}800^{\circ}$, the maximum non-linearity is 0.744% Full Span and the temperature range was $-40^{\circ}C{\sim}+125^{\circ}C$. With this conclusive, the inductive angle sensor was quite satisfactory for many applications in intelligent vehicles.