• Title/Summary/Keyword: active force control

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A Study on the Characteristics of Damping Force in a Hydraulic Actuator for Vehicle Active Suspension System (차량 능동 현가 장치용 유압 액추에이터의 감쇠력 특성에 관한 연구)

  • 윤영환;최명진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.150-158
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    • 2002
  • Through experimental works, the damping force vibration problem was investigated, which results from valve and surge pressure in the oil return line of the hydraulic circuit of an active suspension system in a passenger cu. Experiments were carried out under passive system, where an orifice valve was closed and non-active system, where an orifice valve was opened, using a pressure control valve controlled by solenoid. The effects of parameters of the valve overlap and accumulator on smoothing surge pressure was elucidated. It was proved that the apparent variation of damping force due to the overlap amount of pressure control valve is the most important factor to control the damping force variation. The procedure of the experimental works shows the development process of a proportional pressure control valve in the hydraulics system of an active suspension system of passenger car.

Chaotic particle swarm optimization in optimal active control of shear buildings

  • Gharebaghi, Saeed Asil;Zangooeia, Ehsan
    • Structural Engineering and Mechanics
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    • v.61 no.3
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    • pp.347-357
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    • 2017
  • The applications of active control is being more popular nowadays. Several control algorithms have been developed to determine optimum control force. In this paper, a Chaotic Particle Swarm Optimization (CPSO) technique, based on Logistic map, is used to compute the optimum control force of active tendon system. A chaotic exploration is used to search the solution space for optimum control force. The response control of Multi-Degree of Freedom (MDOF) shear buildings, equipped with active tendons, is introduced as an optimization problem, based on Instantaneous Optimal Active Control algorithm. Three MDOFs are simulated in this paper. Two examples out of three, which have been previously controlled using Lattice type Probabilistic Neural Network (LPNN) and Block Pulse Functions (BPFs), are taken from prior works in order to compare the efficiency of the current method. In the present study, a maximum allowable value of control force is added to the original problem. Later, a twenty-story shear building, as the third and more realistic example, is considered and controlled. Besides, the required Central Processing Unit (CPU) time of CPSO control algorithm is investigated. Although the CPU time of LPNN and BPFs methods of prior works is not available, the results show that a full state measurement is necessary, especially when there are more than three control devices. The results show that CPSO algorithm has a good performance, especially in the presence of the cut-off limit of tendon force; therefore, can widely be used in the field of optimum active control of actual buildings.

Experimental Study on Active Control of Building Structures by Feedback Variables (피드백 변화에 따른 건물의 능동제어 실험)

  • 민경원
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1998.10a
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    • pp.286-294
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    • 1998
  • This paper presents an experimental study on the performance of the active damper device by feedback variables. The damper is a mass-typed active device, which exerts the inertia control force on the building by AC servo motor. The control performance is experimentally analyzed considering the building response and the control force. It is found that the building response is greatly reduced by mass-typed device under the resonant and earthquake loading. Also, the experimental results show that the velocity feedback reduces the building responses with the smallest amount of control force than any other feedback variables.

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Nonlinear Control of Cascade Hybrid Mass Dampers considering Stroke Saturation (스트로크 포화를 고려한 직렬 복합형 감쇠기의 비선형 제어)

  • 민경원;황성호;김성춘;호경찬;김인수
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2000.10a
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    • pp.377-386
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    • 2000
  • Hybrid mass dampers consist of passive tuned mass dampers and active mass dampers. They have the advantage that passive tuned mass dampers are still operated even when active mass dampers are stopped by excessive disturbances or power failure. This paper begins first with the comparative analysis of tuned mass dampers, hybrid mass dampers, and active mass dampers. Next more detailed study is carried out on the hybrid mass dampers: cascade hybrid mass dampers (CHMD) and active tuned mass dampers (ATMD). CHMD is regarded as more reasonable device because of its lighter active mass than ATMD's. However CHMD can not neglect stroke saturation problem caused by the length limitation of active damper mass. We compensate the saturation problem with nonlinear restoring force. The restoring force is calculated based on the states and phases of active mass dampers and added to the control force. It is shown that the presented compensation method prevents CHMD from saturation behavior without apparent changes of control force and responses compared to those in case of not considering the saturation problem.

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Seismic response control of buildings with force saturation constraints

  • Ubertini, Filippo;Materazzi, A. Luigi
    • Smart Structures and Systems
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    • v.12 no.2
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    • pp.157-179
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    • 2013
  • We present an approach, based on the state dependent Riccati equation, for designing non-collocated seismic response control strategies for buildings accounting for physical constraints, with particular attention to force saturation. We consider both cases of active control using general actuators and semi-active control using magnetorheological dampers. The formulation includes multi control devices, acceleration feedback and time delay compensation. In the active case, the proposed approach is a generalization of the classic linear quadratic regulator, while, in the semi-active case, it represents a novel generalization of the well-established modified clipped optimal approach. As discussed in the paper, the main advantage of the proposed approach with respect to existing strategies is that it allows to naturally handle a broad class of non-linearities as well as different types of control constraints, not limited to force saturation but also including, for instance, displacement limitations. Numerical results on a typical building benchmark problem demonstrate that these additional features are achieved with essentially the same control effectiveness of existing saturation control strategies.

Control of a building complex with Magneto-Rheological Dampers and Tuned Mass Damper

  • Amini, F.;Doroudi, R.
    • Structural Engineering and Mechanics
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    • v.36 no.2
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    • pp.181-195
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    • 2010
  • Coupled building control is a viable method to protect tall buildings from seismic excitation. In this study, the semi-active control of a building complex is investigated for mitigating seismic responses. The building complex is formed of one main building and one podium structure connected through Magneto-Rheological (MR) Dampers and Tuned Mass Damper. The conventional semi-active control techniques require a primary controller as a reference to determine the desired control force, and modulate the input voltage of the MR damper by comparing the desired control force. The fuzzy logic directly determines the input voltage of an MR damper from the response of the MR damper. The control performance of the proposed fuzzy control technique for the MR damper is evaluated for the control problem of a seismically-excited building complex. In this paper, a building complex that include a 14-story main building and an 8-story podium structure is applied as a numerical example to demonstrate the effectiveness of semi-active control with Magneto-Rheological dampers and its comparison with the passive control with the Tuned Mass Damper and two uncoupled buildings and hybrid semi-active control including the Tuned Mass Damper and Magneto-Rheological dampers while they are subject to the earthquake excitation. The numerical results show that semi-active control and hybrid semi-active control can significantly mitigate the seismic responses of both buildings, such as displacement and shear force responses, and fuzzy control technique can effectively mitigate the seismic response of the building complex.

A Design of Electromagnet Actuator for Active Vibration Control (능동 진동제어용 전자기 액츄에이터 설계)

  • Lee, Joo-Hoon;Jeon, Jeong-Woo;Hwang, Don-Ha;Kang, Dong-Sik;Choi, Young-Kiu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.522-524
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    • 2005
  • In this paper, we address an actuator system, which suppresses the micro-vibration engaged by environment. The actuator system consists of two modules with a permanent and an electromagnet. In vertical mode, one module is upper the other is lower. For optimal control of alternating vibration, the rate of the attraction force and the repulsion force is exactly one. Generally, the repulsive force is smaller than the attractive force. For linear control of engaged vibration, the ratio of repulsive force and attractive force is designed to equal. The actuator system will be applied to an active vibration control system for precise vibration suppression. In this paper, the actuator structure and its important sizes are calculated by RMS and FEM analysis.

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Active tendon control of suspension bridges

  • Preumont, Andre;Voltan, Matteo;Sangiovanni, Andrea;Mokrani, Bilal;Alaluf, David
    • Smart Structures and Systems
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    • v.18 no.1
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    • pp.31-52
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    • 2016
  • The paper first reviews the theory of active tendon control with decentralized Integral Force Feedback (IFF) and collocated displacement actuator and force sensor; a formal proof of the formula giving the maximum achievable damping is provided for the first time. Next, the potential of the control strategy for the control of suspension bridges with active stay cables is evaluated on a numerical model of an existing footbridge; several configurations are investigated where the active cables connect the pylon to the deck or the deck to the catenary. The analysis confirms that it is possible to provide a set of targeted modes with a considerable amount of damping, reaching ${\xi}=15%$. Finally, the control strategy is demonstrated experimentally on a laboratory mock-up equipped with four control stay cables equipped with piezoelectric actuators. The experimental results confirm the excellent performance and robustness of the control system and the very good agreement with the predictions.

Seismic Response Control of Bridge Structure using Fuzzy-based Semi-active Magneto-rheological Dampers

  • Park, Kwan-Soon;Ok, Seung-Yong;Seo, Chung-Won
    • International Journal of Safety
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    • v.10 no.1
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    • pp.22-31
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    • 2011
  • Seismic response control method of the bridge structures with semi-active control device, i.e., magneto-rheological (MR) damper, is studied in this paper. Design of various kinds of clipped optimal controller and fuzzy controller are suggested as a semi-active control algorithm. For determining the control force of MR damper, clipped optimal control method adopts bi-state approach, but the fuzzy control method continuously quantifies input currents through fuzzy inference mechanism to finely modulate the damper force. To investigate the performances of the suggested control techniques, numerical simulations of a multi-span continuous bridge system subjected to various earthquakes are performed, and their performances are compared with each other. From the comparison of results, it is shown that the fuzzy control system can provide well-balanced control force between girder and pier in the view point of structural safety and stability and be quite effective in reducing both girder and pier displacements over the existing control method.

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Auto Path Generation and Active Compliance Force Control Using 3-axis Grinding Robot (3축 그라인딩 로봇을 이용한 자동 경로 생성 및 능동 컴플라이언스 힘 제어)

  • Choo, Jung-Hoon;Kim, Soo-Ho;Lee, Sang-Bum;Kim, Jung-Min
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.11
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    • pp.1088-1094
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    • 2006
  • In this paper, an auto path generation and an active compliance grinding control using 3-axis farce sensor are presented. These control algorithms enable the grinding robot to follow unknown path of various workpiece shape pattern. The robot is able to go grinding along unknown paths by position controller managing tangential direction angle and cutting speed, with only information about the start position and the end position. Magnitude and direction of normal force are calculated using force data that go through low pass filter. Moreover, normal and tangential directions are separated for force control and velocity control, respectively.