• 제목/요약/키워드: Steering rate

검색결과 167건 처리시간 0.033초

동력조향용 압력평형형 베인펌프의 유량맥동 계측 (Measurement of Flow Ripple Generated by Balanced Vane Pumps in Automotive Power Steering Systems)

  • 김도태;김진
    • 한국자동차공학회논문집
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    • 제8권6호
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    • pp.70-78
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    • 2000
  • A balanced vane pump for the use of automotive power steering systems generates a flow ripple which is imposed upon the mean flow rate. The flow ripple interacts with the characteristics of the connected pipes, valves and steering gear in a complex manner to produce a pressure ripple, also known as fluid-borne noise. In order to reduce vibration level and produce quieter and more reliable power steering systems, it is important to measure the flow ripple produced by a pump with high accuracy and fast response. In this paper, the flow ripple generated by a vane pump in automotive power steering systems is measured by the remote instantaneous flow rate measurement method (RIFM) using hydraulic pipeline dynamics. In experiment, flow and pressure ripple wave forms are measured under various operating conditions. Also, the parameters affected upon the flow and pressure ripple are investigated by the frequency analysis.

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붐방제기의 곡선행로 조향반경에 따른 붐의 구간별 유량제어 (Sectional Flow-rate Control of Boom Sprayer According to the Steering Radius along Winding Rows)

  • 김은수;김영주;이중용
    • Journal of Biosystems Engineering
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    • 제31권3호
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    • pp.146-152
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    • 2006
  • Most upland in Korea have irregular field shapes. Boom sprayers working alone winding row will show considerable differences of spraying amount per unit area between left and right booms. If flow rates of both booms are equal. This phenomenon becomes significant as steering radius of sprayer decreases. This study was performed to seek a method which reduce the difference of the spray amount between left, right and center booms while spraying along curvy rows. A flow rate control method for keeping application rate of each boom section constant was proposed and experimentally proved using a boom sprayer attached to a cultivating tractor. The flow rate control device was composed of 3 ball valves and a rotary angle sensor. The rotary angle sensor showed a symmetric voltage output with respect to steering radius. The spray overlapping was happened in a boom nearby the steering center when steering radius of the sprayer was less than 5.2 m. Flow rates for left, right and center booms were regulated using ball valves based on the steering radius and spraying areas ration of right/left boom. The Maximum spraying area ratio ($S_{LR}$) of left to right boom section was 1:3.6 at the steering radius of 5.2 m. However, The Maximum achieved right and left spraying flow ratio was 1:2.7.

4WS 차량의 모델링 및 동적 해석 (Modeling & Dynamic Analysis for Four Wheel Steering Vehicles)

  • 장진희;정웅상;한창수
    • 한국자동차공학회논문집
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    • 제3권3호
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    • pp.66-78
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    • 1995
  • In this paper, we address vehicle modeling and dynamic analysis of four wheel steering systems (4WS). 4WS is one of the devices used for the improvement of vehicle maneuverability and stability. All research done here is based on a production vehicle from a manufacturer. To study actual system response, a three dimensional, full vehicle model was created. In past research of this type, simple, two dimensional, bicycle vehicle models were typically used. First, we modelled and performed a dynamic analysis on a conventional two wheel steering(2WS) vehicle. The modeling and analysis for this model and subsequent 4WS vehicles were performed using ADAMS(Automatic Dynamic Analysis of Mechanical Systems) software. After the original vehicle model was verified with actual experiment results, the rear steering mechanism for the 4WS vehicle was modelled and the rear suspension was changed to McPherson-type forming a four wheel independent suspension system. Three different 4WS systems were analyzed. The first system applied a mechanical linkage between the front and rear steering mechanisms. The second and third systems used, simple control logic based on the speed and yaw rate of the vehicle. 4WS vehicle proved dynamic results through double lane change test.

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AFS 시스템의 새로운 수학적 모델 및 제어기 개발 (Development of New Numerical Model and Controller of AFS System)

  • 송정훈
    • 한국자동차공학회논문집
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    • 제22권6호
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    • pp.59-67
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    • 2014
  • A numerical model and a controller of Active Front wheel Steer (AFS) system are designed in this study. The AFS model consists of four sub models, and the AFS controller uses sliding mode control and PID control methods. To test this model and controller an Integrated Dynamics Control with Steering (IDCS) system is also designed. The IDCS system integrates an AFS system and an ARS (Active Rear wheel Steering) system. The AFS controller and IDCS controller are compared under several driving and road conditions. An 8 degree of freedom vehicle model is also employed to test the controllers. The results show that the model of AFS system shows good kinematic steering assistance function. Steering ratio varies depends on vehicle velocity between 12 and 24. Kinematic stabilization function also shows good performance because yaw rate of AFS vehicle tracks the reference yaw rate. IDCS shows improved responses compared to AFS because body side slip angle is also reduced. This result also proves that AFS system shows satisfactory result when it is integrated with another chassis system. On a split-m road, two controllers forced the vehicle to proceed straight ahead.

고랑인식 센서 모듈을 이용한 밭고랑 자율조향에 대한 연구 (A Study on Furrow Autonomous Steering using Furrow Recognition Sensor Module)

  • 조용준;박관형;윤해룡;홍형길;오장석;강민수;장선호;서갑호;이영태
    • 한국기계가공학회지
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    • 제21권9호
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    • pp.92-97
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    • 2022
  • In this paper, as a research on autonomous steering for agriculture, a sensor module for furrow recognition was developed through a low-cost distance sensor combination. The developed sensor module was applied to the vehicle, and when driving in a furrow curve, the autonomous steering success rate was 100% at a curvature of 20 m or more, and 70% at a curvature of 15 m or less. The self-steering success rate according to the ground condition showed a 100% success rate regardless of soil, weeds, or mulching film.

기동성을 위한 후륜 조향 차량의 최적 성능에 대한 연구 (An Experimental Study of Optimal Performance of Rear Wheel Steering Vehicle for Maneuverability)

  • 안국진;좌은혁;박관우;윤영식;이경수
    • 자동차안전학회지
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    • 제11권2호
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    • pp.23-28
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    • 2019
  • This paper presents an optimal performance of rear wheel steering vehicle for maneuverability. The maneuverability of vehicle is evaluated in terms of yaw rate, body slip angle and driver input. The maneuverability of vehicle can be improved by rear wheel steering system. To obtain optimal performance of rear wheel steering vehicle, the optimal control history is designed. The high dimensional trajectory optimization problem is solved by formulating a quadratic program considering rear wheel steer input. To evaluate handling performance 7 degree-of-freedom vehicle model with actuation sub-models is designed. A step steer test is conducted to evaluate rear wheel steering vehicle. A response time, a TB factor, overshoot, and yaw rate gain are investigated through objective criteria, assessment webs. The handling performance of vehicle is evaluated via computer simulations. It has been shown from simulation studies that optimal controlled rear wheel steering vehicle provides improved performance compared to others.

차량의 선회시 주행 안정성 강화를 위한 ESP 시스템 개발 및 성능 평가 (II) (Development and Evaluation of ESP Systems for Enhancement of Vehicle Stability during Cornering (II))

  • 송정훈
    • 대한기계학회논문집A
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    • 제30권12호
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    • pp.1551-1556
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    • 2006
  • Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a rear wheel steering yaw motion controller (SESP) and an enhanced rear wheel steering yaw motion controller (ESESP). A SESP controls the rear wheels, while an ESESP steers the rear wheels and front outer wheel to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed SESP and ESESP. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the SESP and ESESP are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads.

전동식 조향 장치의 성능 평가를 위한 신경 근육계 기반 운전자 모델 개발 (Development of Human Driver Model based on Neuromuscular System for Evaluation of Electric Power Steering System)

  • 이성현;이동필;이재풍;채흥석;이명수;이경수
    • 자동차안전학회지
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    • 제9권3호
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    • pp.19-23
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    • 2017
  • This paper presents a lateral driver model with neuromuscular system to evaluate the performance of electric power steering (EPS). Output of most previously developed driver models is steering angle. However, in order to evaluate EPS system, driver model which results in steering torque output is needed. The proposed lateral driver model mainly consists of 2 parts: desired steering angle calculation and conversion of steering angle into steering torque. Desired steering angle calculation part results in steering angle to track desired yaw rate for path tracking. Conversion of steering angle into torque is consideration with neuromuscular system. The proposed driver model is investigated via actual driving data. Compared to other algorithms, the proposed algorithm shows similar pattern of steering angle with human driver. The proposed driver can be utilized to efficiently evaluate EPS system in simulation level.

유량 및 부하가 변하는 상태에서의 양로드 유압실린더의 위치제어시스템 (Position Control System of a Double-end Rod Hydraulic Cylinder under Variable Flow Rate and Load Conditions)

  • 김대철;김동화;이재규;신범수
    • Journal of Biosystems Engineering
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    • 제34권5호
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    • pp.331-341
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    • 2009
  • A double-end rod hydraulic cylinder is widely used with a steering valve for the steering control system in large tractors. For the development of automatic steering controller, the feasibility of using a proportional control valve replacing the conventional manual steering valve to control the position of hydraulic steering cylinder was investigated in terms of the max. overshoot, the steady-state error and the rise time. A simulation model for the electrohydraulic steering system with load using AMESim package was developed to be valid so that the proper control algorithm could be chosen through the computer simulation. It could be concluded that the P-control algorithm was sufficient to control the electrohydraulic steering system, where the control frequency should be no greater than 20 Hz at the P-gain of 5. In particular, the performance of the developed steering controller was satisfactory even at the conditions of varying flow rates and loads.