• Title/Summary/Keyword: active suspensions

Search Result 56, Processing Time 0.026 seconds

A Study on the Field Test Characteristics of Semi-Active Suspension System with Continuous Damping Control Damper (감쇠력 가변댐퍼를 이용한 반능동 현가장치의 실차실험 특성에 관한 연구)

  • Lee, K.H.;Lee, C.T.;Jeong, H.S.
    • Transactions of The Korea Fluid Power Systems Society
    • /
    • v.7 no.4
    • /
    • pp.32-38
    • /
    • 2010
  • A semi-active suspension is an automotive technology that controls the vertical movement of the vehicle while the car is driving. The system therefore virtually eliminates body roll and pitch variation in many driving situations including cornering, accelerating, and braking. This technology allows car manufacturers to achieve a higher degree of both ride quality and car handling by keeping the tires perpendicular to the road in corners, allowing for much higher levels of grip and control. An onboard computer detects body movement from sensors located throughout the vehicle and, using data calculated by opportune control techniques, controls the action of the suspension. Semi-active systems can change the viscous damping coefficient of the shock absorber, and do not add energy to the suspension system. Though limited in their intervention (for example, the control force can never have different direction than that of the current speed of the suspension), semi-active suspensions are less expensive to design and consume far less energy. In recent time, the research in semi-active suspensions has continued to advance with respect to their capabilities, narrowing the gap between semi-active and fully active suspension systems. In this paper we are studied the characteristics of vehicle movement during the field test with conventional and semi-active suspension system.

  • PDF

A Study on Dynamic Modeling of the Vibration Isolation System for the Ultra Precision Measurement (초정밀작업을 위한 제진시스템의 동역학 모델링 연구)

  • Son, Sung-Wan;Jang, Sung-Ho;Baek, Jae-Ho;Chun, Chong-Keun;Kwon, Young-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.10 no.1
    • /
    • pp.25-31
    • /
    • 2009
  • The anti-vibration tables that use air suspensions as dampers have been widely used due to their high anti-vibration performance in wide frequency band. However, they face a problem of easily accelerating the vibration when triggered by external force because their air suspensions have low rigidity and dampness. In response, there has been a study on active/semi-active dampers that use only the passive components like air suspensions to complement the passive-control format. Thus, we have dynamically analyzed the active/semi-active control of such passive anti-vibration tables. To demonstrate the anti-vibration table's control system, we have also constructed a kinetic model based on the physical characteristics of an anti-vibration table with 6 degrees of freedom and verified its applicability through analysis and experiments.

LQG Controller Design for Active Suspensions using Evolution Strategy and Neural Network (진화전략과 신경회로망을 이용한 능동 현가장치 LQG 제어기 설계)

  • Cheon, Jong-Min;Kim, Jong-Moon;Park, Min-Kook;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
    • /
    • 2006.10c
    • /
    • pp.266-268
    • /
    • 2006
  • In this paper, we design a Linear Quadratic Gaussian(LQG) controller for active suspensions. We can improve the inherent suspension problem, trade-off between the ride quality and the suspension travel by selecting appropriate weights in the LQ-objective function. Using an optimization-algorithm, Evolution Strategy(ES), we find the proper control gains for selected frequencies, which have major effects on the vibrations of the vehicle's state variables. The frequencies and proper control gains are used for the neural network data. During a vehicle running, the trained on-line neural network is activated and provides the proper gains for non-trained frequencies.

  • PDF

A Design of Vehicle Active Suspension Controller with Variable Control Objects Determined by Driving Conditions (주행 상황에 따라 다양한 제어목적을 가지는 차량 능동 현가장치 제어기 설계)

  • Cheon, Jong-Min;Kim, Seog-Joo;Park, Jong-Moon;Kwon, Soon-Man
    • Proceedings of the KIEE Conference
    • /
    • 2005.10b
    • /
    • pp.346-348
    • /
    • 2005
  • In this paper, we designed a vehicle active suspension controller. Vehicle suspensions have various design objects with tradeoff among them and these objects cannot be satisfied under all driving conditions. We need to design a controller adapted to variable driving conditions changing the objects of vehicle suspensions. To design such a controller, we must be able to detect the current driving conditions and focus on the road frequencies giving us useful and important information about driving conditions. Detecting the road frequencies, we use the Fourier Transform. A unexpected driving change like a speed bump was also included to items the new designed controller must consider.

  • PDF

COMPLEX STOCHASTIC WHEELBASE PREVIEW CONTROL AND SIMULATION OF A SEMI-ACTIVE MOTORCYCLE SUSPENSION BASED ON HIERARCHICAL MODELING METHOD

  • Wu, L.;Chen, H.L.
    • International Journal of Automotive Technology
    • /
    • v.7 no.6
    • /
    • pp.749-756
    • /
    • 2006
  • This paper presents a complex stochastic wheelbase preview control method of a motorcycle suspension based on hierarchical modeling method. As usual, a vehicle suspension system is controlled as a whole body. In this method, a motorcycle suspension with five Degrees of Freedom(DOF) is dealt with two local independent 2-DOF suspensions according to the hierarchical modeling method. The central dynamic equations that harmonize local relations are deduced. The vertical and pitch accelerations of the suspension center are treated as center control objects, and two local semi-active control forces can be obtained. In example, a real time Linear Quadratic Gaussian(LQG) algorithm is adopted for the front suspension and the combination of the wheelbase preview and LQG control method is designed for the rear suspension. The results of simulation show that the control strategy has less calculating time and is convenient to adopt different control strategies for front and rear suspensions. The method proposed in this paper provides a new way for the vibration control of multi-wheel vehicles.

Nonlinear Control of Active Suspensions using RBF Network with Asymmetric Hydraulic Cylinder (비대칭형 유압 실린더를 사용한 능동 현가 시스템의 RBF 신경회로망을 이용한 제어기 설계)

  • Jang, Yu-Jin;Kim, Sang-U
    • The Transactions of the Korean Institute of Electrical Engineers A
    • /
    • v.48 no.5
    • /
    • pp.593-600
    • /
    • 1999
  • This paper suggests a suboptimal control scheme of an active suspension system with an asymmetric hydraulic cylinder. In this paper a quarter car model including a nonlinear actuator dynamics is used. A feedback linearization technique is applied to obtain a linear model. An LQ regulator is designed with the linear model to keep robustness against sprung mass variation. The gain of the LQ regulator which depends on the damping coefficient of the damper is calculated by using an RBF neural network for real time application. The improvement achieved with our design is illustrated through comparative simulations.

  • PDF

States/Road Input Observer-based Control of Semi-active Suspensions (상태변수/노면입력 관측기를 이용한 반능동 현가시스템 제어)

  • 김정헌;이경수
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.8 no.2
    • /
    • pp.102-109
    • /
    • 2000
  • This paper deals with an observer-based preview control for semi-active suspensions. An Observer has been designed such that all the state variables and road inputs can be estimated from accelerations. Since the road input to the rear wheels is a delayed version of that to the front wheels, it can be obtained by estimating the road input to the front wheels without preview the estimated values of state and the estimated road input has been investigated. The results show that the observer-based control can provide good performance. The observer-based preview control improves the dynamic behavior of the rear axle and that of pitch motion compared to the LQ optimal control.

  • PDF

OPTIMAL PREVIEW CONTROL OF TRACKED VEHICLE SUSPENSION SYSTEMS

  • Youn, I.;Lee, S.;Tomizuka, M.
    • International Journal of Automotive Technology
    • /
    • v.7 no.4
    • /
    • pp.469-475
    • /
    • 2006
  • In this paper, an optimal suspension system with preview of the road input is synthesized for a half tracked vehicle. The main goal of this research is to improve the ride comfort characteristics of a fast moving tracked vehicle in order to maintain the driver's driving capability. Several different kinds of preview control algorithms are evaluated with active or semi-active suspension systems. The road information estimated from the motion of the 1st road-wheel is adequate to make the best use of the preview control algorithm for tracked vehicles. The ride-comfort characteristics of the tracked vehicle are more dependent on pitching angular acceleration than heaving acceleration. The pitching motion is reduced by the suspension system with hard outer suspensions and soft inner suspensions. Simulation results show that the performance of sky-hook algorithms for ride comfort nearly follow that of full state feedback algorithms.

Simultaneous Optimization of Vehicle Suspensions for the Improvement of Frequency-weighted Riding Comfort (주파수 가중치를 고려한 승차감의 향상을 위한 차량 현가장치의 동시최적화)

  • 김창동;정의봉
    • Journal of KSNVE
    • /
    • v.5 no.1
    • /
    • pp.29-35
    • /
    • 1995
  • This paper presents the simultaneous optimal design of structure and LQG control systems for the improvement of riding comforts of active vehicle suspension systems. The performance index of riding comforts is extended to include frequency-weighted acceleration in the quadratic cost functional. Janeway human response curve with respect to acceleration is used to verify the usefulness of the presented method. The method is applied to a half model of an active vehicle suspension systems with elastic body moving on randomly profiled road. The values of stiffness of suspensions are used for the structural design variables. The conjugate gradient method is used for optimization. The simulated results of simultaneous optimization with frequency-weighted cost functional are compared with those without frequency- weighted cost functional.

  • PDF

Design of Semi-Active suspension system for Railway Vehicle with narrow gauge (협궤 차량용 준능동형 현가 시스템 설계)

  • Lee Nam-Jin;Kim Chul-Gun;Nam Hak-Gi
    • Proceedings of the KSR Conference
    • /
    • 2005.05a
    • /
    • pp.473-478
    • /
    • 2005
  • Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.

  • PDF