• 제목/요약/키워드: slip angle

검색결과 295건 처리시간 0.024초

감지시스템을 통한 차량의 횡 속도 및 슬립각 추정 (Monitoring System Design for Estimating Lateral Velocity and Sideslip Angle)

  • 한상오;허건수
    • 한국자동차공학회논문집
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    • 제19권1호
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    • pp.51-57
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    • 2011
  • Information of the lateral velocity and the sideslip angle in a vehicle is very useful in many active vehicle safety applications such as yaw stability control and rollover prevention. Because cost-effective sensors to measure the lateral velocity and the sideslip angle are not available, reliable algorithms to estimation them are necessary. In this paper, a sliding mode observer is designed to estimate the lateral velocity. The side slip angle is estimated using the recursive least square with the disturbance observer and the pseudo integral. The estimated parameters from the combined estimation method are updated recursively to minimize the discrepancy between the model and the physical plant, and any possible effects caused by disturbances. The performance of the proposed monitoring system is evaluated through simulations and experiments.

Clinical and Radiological Outcomes of Foraminal Decompression Using Unilateral Biportal Endoscopic Spine Surgery for Lumbar Foraminal Stenosis

  • Kim, Ju-Eun;Choi, Dae-Jung;Park, Eugene J.
    • Clinics in Orthopedic Surgery
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    • 제10권4호
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    • pp.439-447
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    • 2018
  • Background: Since open Wiltse approach allows limited visualization for foraminal stenosis leading to an incomplete decompression, we report the short-term clinical and radiological results of unilateral biportal endoscopic foraminal decompression using $0^{\circ}$ or $30^{\circ}$ endoscopy with better visualization. Methods: We examined 31 patients that underwent surgery for neurological symptoms due to lumbar foraminal stenosis which was refractory to 6 weeks of conservative treatment. All 31 patients underwent unilateral biportal endoscopic far-lateral decompression (UBEFLD). One portal was used for viewing purpose, and the other was for surgical instruments. Unilateral foraminotomy was performed under guidance of $0^{\circ}$ or $30^{\circ}$ endoscopy. Clinical outcomes were analyzed using the modified Macnab criteria, Oswestry disability index, and visual analogue scale. Plain radiographs obtained preoperatively and 1 year postoperatively were compared to analyze the intervertebral angle (IVA), dynamic IVA, percentage of slip, dynamic percentage of slip (gap between the percentage of slip on flexion and extension views), slip angle, disc height index (DHI), and foraminal height index (FHI). Results: The IVA significantly increased from $6.24^{\circ}{\pm}4.27^{\circ}$ to $6.96^{\circ}{\pm}3.58^{\circ}$ at 1 year postoperatively (p = 0.306). The dynamic IVA slightly decreased from $6.27^{\circ}{\pm}3.12^{\circ}$ to $6.04^{\circ}{\pm}2.41^{\circ}$, but the difference was not statistically significant (p = 0.375). The percentage of slip was $3.41%{\pm}5.24%$ preoperatively and $6.01%{\pm}1.43%$ at 1-year follow-up (p = 0.227), showing no significant difference. The preoperative dynamic percentage of slip was $2.90%{\pm}3.37%$; at 1 year postoperatively, it was $3.13%{\pm}4.11%$ (p = 0.720), showing no significant difference. The DHI changed from $34.78%{\pm}9.54%$ preoperatively to $35.05%{\pm}8.83%$ postoperatively, which was not statistically significant (p = 0.837). In addition, the FHI slightly decreased from $55.15%{\pm}9.45%$ preoperatively to $54.56%{\pm}9.86%$ postoperatively, but the results were not statistically significant (p = 0.705). Conclusions: UBEFLD using endoscopy showed a satisfactory clinical outcome after 1-year follow-up and did not induce postoperative segmental spinal instability. It could be a feasible alternative to conventional open decompression or fusion surgery for lumbar foraminal stenosis.

비원형기어에서의 압력각과 잇수비 및 곡률반경의 적정범위에 관한 연구 (A Study on the Proper Scope for Pressure Angle, Ratio of Tooth Number & Radius of Curvature in Non-Circular Gears)

  • Park, S.H.
    • 한국정밀공학회지
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    • 제14권6호
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    • pp.52-63
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    • 1997
  • Non-circular gear has a good velocity ratio in high speed and heavy load without any slip, moreover, it can transmit various motion, using simpler structure than link and cam, automation mechainism. In case of designing and manufacturing non-circular gear. I suggest one of references in applying non-circular gear to industrial plant, and suitable range of application by pressure angle curvature and angle ratio

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GPS/INS 를 이용한 차량의 파라미터 추정 (Estimation of vehicle parameters using GPS/INS)

  • 박건홍;장유신;류재헌;박석현;이춘한;홍신표;이만형
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.1524-1529
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    • 2003
  • In this paper deals with a unique method for measuring vehicle states such as body sideslip angle and tire sideslip angle using GPS velocity information in conjunction with other sensors. A method for integrating Inertial Navigation System (INS) sensors with GPS measurements to provide higher update rate estimates of the vehicle states is presented, and the method can be used to estimate the tire cornering stiffness. The experimental results for the GPS velocity-based sideslip angle measurement and cornering stiffness estimates are compared with the theoretical predictions. From the experimental results, it can be concluded that the proposed method has an advantage for future implementation in a vehicle safety system.

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Behavior of steel-concrete composite beam using angle shear connectors at fire condition

  • Davoodnabi, Seyed Mehdi;Mirhosseini, Seyed Mohammad;Shariati, Mahdi
    • Steel and Composite Structures
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    • 제30권2호
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    • pp.141-147
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    • 2019
  • Fire is one of the environmental parameters affecting the structure causing element internal forces to change, as well as reducing the strength of the materials. One of the common types of floors in tall steel structures is the steel concrete composite slab. Shear connectors are used in steel and concrete composite beam in various shapes also has played significant role in a burning fire event of building with a steel concrete composite beam. The current study has reviewed the effects of temperature raising on the angle connector behavior through the use of push out tests and monotonic static force. The results have shown (1) the ductility of the samples is acceptable based on EC4 standard; (2) temperature raising has reduced the stiffness; (3) the shear ductility increment; and (4) the shear capacity reduction. Also, the amount of angle shear connector resistance has been decreased from 18.5% to 41% at ambient temperature up to $850^{\circ}C$.

Interfacial shear resistance of angle shear connectors welded to concrete filled U-shaped CFS beam

  • Oh, Hyoung Seok;Shin, Hyeongyeop;Ju, Youngkyu;Kang, Thomas H.K.
    • Steel and Composite Structures
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    • 제43권3호
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    • pp.311-325
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    • 2022
  • For multi-story structural systems, Korean steel industry has fostered development of a steel-concrete composite beam. Configuration of the composite beam is characterized by steel angle shear connectors welded to a U-shaped cold formed-steel beam. Effects of shear connector orientation and spacing were studied to evaluate current application of the angle shear connector design equation in AC495. For the study, interfacial shear resistance behavior was investigated by conducting 24 push-out tests and attuned using unreinforced push-out specimens. Interfacial shear to horizontal slip response was reported along with corresponding failure patterns. Pure shear connector strength was also evaluated by excluding concrete shear contribution, which was estimated in relation to steel beam-slab interface separation or interfacial crack width.

전륜 제동력 및 전륜 조향각을 이용한 SUV 차량의 통합운동제어시스템 개발 (Integrated Dynamics Control System for SUV with Front Brake Force and Front Steering Angle)

  • 송정훈
    • 한국기계가공학회지
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    • 제21권5호
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    • pp.22-27
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    • 2022
  • An integrated front steering system and front brake system (FSFB) is developed to improve the stability and controllability of an SUV. The FSFB simultaneously controls the additional steering angle and front brake pressure. An active front steering system (AFS) and an active front brake system (AFB) are designed for comparison. The results show that the FSFB enhances the lateral stability and controllability regardless of road and running conditions compared to the AFS and AFB. As a result, the yaw rate of the SUV tracks the reference yaw rate, and the side slip angle decreases. In addition, brake pressure control is more effective than steering angle control in improving the stability and steerability of the SUV on a slippery road. However, this deteriorates comfort on dry or wet asphalt.

이중너클을 이용한 후륜 토 및 캠버각 변화를 통한 조종안정성 개선 (Improvement of Vehicle Handling Performance due to Toe and Camber Angle Change of Rear Wheel by Using Double Knuckle)

  • 손정현;박성준
    • 한국자동차공학회논문집
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    • 제21권1호
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    • pp.121-127
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    • 2013
  • In this study, suspension geometry is controlled to improve vehicle handling performance. The toe and camber of the rear suspension is controlled independently by using a double knuckle structure designed to enhance the vehicle cornering stability. Camber and toe changes in the rear wheel during high speed turning maneuver are important factors that influence the vehicle stability. Toe in the rear outer wheel plays a dominant role in cornering. A control algorithm for the camber and the toe angle input is developed to carry out the control simulation of the vehicle such as single lane change, the steady state cornering, the double lane change and the step steering simulation. Effects of the camber and toe angle control are analyzed from the computer simulations. A double lane change simulation revealed that the suspension mechanism with variable camber angle and variable toe angle decreases the peak body slip angle and peak yaw rate, 50% and 10%, respectively.

INTEGRATED CONTROL SYSTEM DESIGN OF ACTIVE FRONT WHEEL STEERING AND FOUR WHEEL TORQUE TO IMPROVE VEHICLE HANDLING AND STABILITY

  • Wu, J.Y.;Tang, H.J.;Li, S.Y.;Zheng, S.B.
    • International Journal of Automotive Technology
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    • 제8권3호
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    • pp.299-308
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    • 2007
  • This study proposes a two-layer hierarchical control system that integrates active front wheel steering and four wheel braking torque control to improve vehicle handling performance and stability. The first layer is a robust model matching controller (R-MMC) based on linear matrix inequalities (LMIs), which optimizes an active front steering angle compensation and a desired yaw moment control, and calculates reference wheel slip for the target wheel according to the desired yaw moment. The second layer is a moving sliding mode controller (MSMC) that can track the reference wheel slip in a predetermined time by commanding proper braking torque on the target wheel to achieve the desired yaw moment. Since vehicle sideslip angle measurement is difficult to achieve in practice, a sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed in this study. The performance and robustness of the SMO and the integrated control system are demonstrated through comprehensive computer simulations. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.

해저 집광차량의 위치 추정을 위한 확장 칼만 필터 알고리즘 (Development of an Extended Kalman Filter Algorithm for the Localization of Underwater Mining Vehicles)

  • 원문철;차혁상;홍섭
    • 한국해양공학회지
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    • 제19권2호
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    • pp.82-89
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    • 2005
  • This study deals with the development of the extended Kalman filter(EKF) algorithm for the localization of underwater mining vehicles. Both simulation and experimental studies in a test bed are carried out. For the experiments, a scale dawn tracked vehicle is run in a soil bin containing cohesive soil of bentonite-water mixture. To develop the EKF algorithm, we use a kinematic model including the inner/outer track slips and the slip angle for the vehicle. The measurements include the inner and outer wheel speeds from encoders, the heading angle from a compass sensor and a fiber optic rate gyro, and x and y coordinate position values from a vision system. The vision sensor replaces the LBL(Long Base Line) sonar system used in the real underwater positioning situations. Artificial noise signals mimicking the real LBL noise signal are added to the vision sensor information. To know the mean slip values of the tracks in both straight and cornering maneuver, several trial running experiments are executed before applying the EKF algorithm. Experimental results show the effectiveness of the EKF algorithm in rejecting the sensor measurements noise. Also, the simulation and experimental results show close correlations.