• Title/Summary/Keyword: Active Force control

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Self-Tuning Modified Skyhook Control for Semi -Active Suspension Systems (자기동조기법을 이용한 반능동 현가장치의 수정된 스카이훅제어 구현 및 실험)

  • 정재룡;손현철;홍금식
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.114-114
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    • 2000
  • In this paper a self-tuning modified skyhook control for the semi-active suspension systems is investigated. The damping force generation mechanism is modeled We consider a 2 DOF time-varying quarter car model that permits parameter variations of the sprung mass and suspension spring coefficient. The modified skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters, according to parameter variations. The skyhook gains are designed in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype will be discussed

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Vibration Control of a Vehicle using ER Damper (ER댐퍼를 이용한 차량의 진동제어)

  • Joo, Dong-Woo;Lee, Yuk-Hyung;Park, Myeong-Kwan
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.5 s.98
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    • pp.104-111
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    • 1999
  • A semi-active suspension system for a vehicle using an Electrorheological Fluid damper has been studied. Apparent viscosity of ERF(Electrorheological Fluid) can be changed rapidly by applying electric field. The damping force of ER damper can be selectively controlled by employing electric field to the ER fluid domain. This paper deals with a two-degree-of-freedom suspension using the ER damper for a quarter car model. An intelligent control method using fuzzy control with genetic algorithm has been employed to control the damping force of the ER damper. The GA designs the optimal structure and performance of Fuzzy Net Controller having hybrid structure. The designed fuzzy net controller has been compared with the skyhook type controller for a quarter car model. The computer simulation results show that the semi-active suspension with ER damper has a good performance in the sense of ride quality with less vibration for ground vehicle.

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Analog active valve control design for non-linear semi-active resetable devices

  • Rodgers, Geoffrey W.;Chase, J. Geoffrey;Corman, Sylvain
    • Smart Structures and Systems
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    • v.19 no.5
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    • pp.487-497
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    • 2017
  • Semi-active devices use the building's own motion to produce resistive forces and are thus strictly dissipative and require little power. Devices that independently control the binary open/closed valve state can enable novel device hysteresis loops that were not previously possible. However, some device hysteresis loops cannot be obtained without active analog valve control allowing slower, controlled release of stored energy, and is presents an ongoing limitation in obtaining the full range of possibilities offered by these devices. This in silico study develops a proportional-derivative feedback control law using a validated nonlinear device model to track an ideal diamond-shaped force-displacement response profile using active analog valve control. It is validated by comparison to the ideal shape for both sinusoidal and random seismic input motions. Structural application specific spectral analysis compares the performance for the non-linear, actively controlled case to those obtained with an ideal, linear model to validate that the potential performance will be retained when considering realistic nonlinear behaviour and the designed valve control approach. Results show tracking of the device force-displacement loop to within 3-5% of the desired ideal curve. Valve delay, rather than control law design, is the primary limiting factor, and analysis indicates a ratio of valve delay to structural period must be 1/10 or smaller to ensure adequate tracking, relating valve performance to structural period and overall device performance under control. Overall, the results show that active analog feedback control of energy release in these devices can significantly increase the range of resetable, valve-controlled semi-active device performance and hysteresis loops, in turn increasing their performance envelop and application space.

Design of A Controller for Vehicle Active Suspensions Considering Driving Conditions (주행 상황을 고려한 차량 능동 현가장치 제어기 설계)

  • Cheon Jong-Min;Lee Jong-Moo;Kwon Soonman;Choi Young-Kiu
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.54 no.12
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    • pp.698-704
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    • 2005
  • Passive suspensions with fixed design constants are very restrictive in the inherent suspension problem, the trade-off between the ride quality and the suspension travel. Active suspensions are used to solve some drawbacks of passive suspensions. In this paper, we propose a controller design for vehicle active suspensions considering variable driving conditions. Our controller estimates the current driving conditions by detecting the road frequencies gotten from Fourier Transform and decides which factor must be emphasized between the ride quality and the suspension travel. In one case of focusing on the ride quality, we use the skyhook control law and in the other case of focusing on the suspension travel, the double skyhook control law is used. The control law modified by various road situations outputs the reference force value the electro-hydraulic actuator in active suspension system must generate. To track the reference force, we adopt the sliding control law which is very useful in controlling the nonlinear system like the electro-hydraulic actuator.

The control of an upper extremity exoskeleton for stroke rehabilitation: An active force control scheme approach

  • Majeed, Anwar P.P. Abdul;Taha, Zahari;Abdullah, Muhammad Amirul;Azmi, Kamil Zakwan Mohd;Zakaria, Muhammad Aizzat
    • Advances in robotics research
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    • v.2 no.3
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    • pp.237-245
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    • 2018
  • This study evaluates the efficacy of a class robust control scheme namely active force control in performing a joint based trajectory tracking of an upper limb exoskeleton in rehabilitating the elbow joint. The plant of the exoskeleton system is obtained via system identification method whilst the PD gains were tuned heuristically. The estimated inertial parameter that enables the AFC disturbance rejection effect is attained by means of a non-nature based metaheuristic optimisation technique known as simulated Kalman filter (SKF). It was demonstrated from the present investigation that the proposed PDAFC scheme outperformed the classical PD algorithm in tracking the prescribed trajectory both in the presence and without the presence of disturbance attributed by the mannequin limb weights (1 kg and 1.5 kg) that mimics the weight of actual human limb weight. Therefore, it is apparent from the results obtained from the present study that the proposed control scheme, i.e., PDAFC is suitable for the application of exoskeleton for stroke rehabilitation.

A Study on Active Vibration Isolation Using Electro-Magnetic Actuator (전자기력을 이용한 능동제진에 관한 연구)

  • 손태규;김규용;박영필
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.5
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    • pp.1169-1181
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    • 1994
  • Vibration isolation of mechanical systems, in general, is achieved through passive or active vibration isolators. Passive vibration isolator has an inherenrt performance limitation. Whereas, active vibration isolator provides significantly superior vibration-isolation performance at the cost of energy sources and sensors. Recently, in many cases, such as suspension system, precision machinery ... etc, active isolation system outweighs its limitation. Therefore, many studies, researches, and applications are carried out in this field. In this study, vibration-isolation characteristics of an active vibration control system using electromagnetic force actuator are investigated. Several control algorithms including optimal, feedforward are used for active vibration isolation. From the experimental results of each algorithm, effective control algorithms for this active vibration-isolation system are proposed.

Optimal controller design for active suspension system with asymmetric hydraulic cylinder using feedback linearization (비대칭형 유압실린더를 사용한 능동현가 시스템에서의 Feedback Linearization을 이용한 최적 제어기 설계)

  • Jang, Yu-Jin;Kim, Sang-Woo;Park, Poo-Gyeon
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.644-647
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    • 1997
  • Asymmetric cylinders are usually used as an actuator of active suspensions. The conventional optimal controller design does not include actuator dynamics as a state and force controller is needed to track the desired force. But the actuator is not ideal, so performance of an active suspension system is degraded. In this paper, we take account nonlinear actuator dynamics and obtain a linear model using a feedback linearization technique then apply optimal control method. Effectiveness of proposed method is demonstrated by numerical simulation of 1/4 car model.

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Damping performance Analysis for an Electronically Contralled Shock Absorber (연속 가변형 충격흡수기의 감쇠성능 해석)

  • 박재우;이동락;백운경
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.2
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    • pp.192-201
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    • 2001
  • Analyzing internal structure, flow rate and dynamic behavior characteristics of electronically controlled shock absorber, damping performance limit is identified to comprise the two reciprocal characteristics of ride comfort and handling safety. Regardless of its lower performance than the active suspension control system, the semi-active suspension control system has been taking interest because of its absolutely higher performance than passive suspension system. Since the pervious studies have been concentrated mostly on analytic aspect and survey on the internal structure of the shock absorber remain insufficient, the main discourse of this paper is focused on analyzing the nonlinear shock absorber which varies the damping force of semi-active suspension system and the dynamic characteristics of the solenoid valve, a sort of pressure valve, and proposing the design factors of importance.

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Helicopter Active Airframe Vibration Control Simulations Using an Exhaustive Test Method (Exhaustive 시험 기법을 이용한 헬리콥터 능동 기체 진동 제어 시뮬레이션)

  • Park, Byeong-Hyeon;Lee, Ye-Lin;Park, Jae-Sang
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.11
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    • pp.791-800
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    • 2022
  • The number and locations of force generators and their force directions of Active Vibration Control System(AVCS) are important to maximize the airframe vibration reduction performance of helicopters. The present AVCS simulation using an exhaustive test method attempts to determine the best number and locations of force generators and their force directions for maximization of the airframe vibration reduction performance of UH-60A helicopter at 158 knots. The 4P hub vibratory loads of the UH-60A helicopter are calculated using DYMORE II, a nonlinear multibody dynamics analysis code, and MSC.NASTRAN is used to predict the vibration responses of the UH-60A airframe. The AVCS framework with an exhaustive test method is constructed using MATLAB Simulink. As a result, when applying AVCS with the optimal combination of the force generators, the 4P airframe vibration responses of UH-60A helicopter are reduced by from 19.35% to 98.07% compared to the baseline results without AVCS.

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
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    • 2005.05a
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    • pp.473-478
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    • 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.

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