• Title/Summary/Keyword: Force feedback

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Active Vibration Control System Using Electromagnet Actuator (전자기 액츄애이터를 이용한 능동 진동제어시스템)

  • Lee, Joo-Hoon;Jeon, Jeong-Woo;Hwang, Don-Ha;Kang, Dong-Sik;Choi, Young-Kiu
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2809-2811
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    • 2005
  • In this paper, we address an active vibration control system, which suppresses the vibration engaged by magnetically levitated stage. The stage system consists of a levitating platen with four permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion via the vertical and horizontal forces. In the stage system, which represents the settling-time critical system, the motion of the platen vibrates mechanically. We designed an active vibration control system for suppressing vibration due to the stage moving. The command feedforward with inertial feedback algorithm is used for solving stage system's critical problems. The components of the active vibration control system are accelerometers for detecting stage tables's vibrations, a digital controller with high precise signal converters, and electromagnetic actuators.

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Overview of Human Adaptive Mechatronics and Assist-control to Enhance Human's Proficiency

  • Suzuki, Satoshi;Furuta, Katsuhisa;Harashima, Fumio
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1759-1764
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    • 2005
  • Human Adaptive Mechatronics(HAM) is a new concept which was proposed in our university's research project sponsored by Japanese Ministry of Education, Sports, Culture, Science and Technology(MEXT), and is defined as "intelligent mechanical systems that adapt themselves to the user's skill under various environments, assist to improve the user's skill, and assist the human-machine system to achieve best performance". In this paper, the concept and key-items of HAM are mentioned. And the control strategy to realize a HAM human-machine system is explained in the case of physical-interface system, i.e. haptic system. The proposed assist-control of a force-feedback type haptic system includes online estimation of a operator's control characteristics, and a `force assist' function implemented as a change in the support ratio according to the identified skill level. We developed a HAM-haptic device test system, executed evaluation experiments with this apparatus, and analyzed the measured data. It was confirmed that the operator's skill could be estimated and that operator's performance was enhanced by the assist-control.

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The Electrical Characterization of Magnetic Tunneling Junction Cells Using Conductive Atomic Force Microscopy with an External Magnetic Field Generator

  • Heo, Jin-Hee
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.6
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    • pp.271-274
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    • 2010
  • We examined the tunneling current behaviors of magnetic tunneling junction (MTJ) cells utilizing conductive atomic force microscopy (AFM) interfaced with an external magnetic field generator. By introducing current through coils, a magnetic field was generated and then controlled by a current feedback circuit. This enabled the characterization of the tunneling current under various magnetic fields. The current-voltage (I-V) property was measured using a contact mode AFM with a metal coated conducting cantilever at a specific magnetic field intensity. The obtained magnetoresistance (MR) ratios of the MTJ cells were about 21% with no variation seen from the different sized MTJ cells; the value of resistance $\times$ area (RA) were 8.5 K-12.5 K $({\Omega}{\mu}m^2)$. Since scanning probe microscopy (SPM) performs an I-V behavior analysis of ultra small size without an extra electrode, we believe that this novel characterization method utilizing an SPM will give a great benefit in characterizing MTJ cells. This novel method gives us the possibility to measure the electrical properties of ultra small MTJ cells, namely below $0.1\;{\mu}m\;{\times}\;0.1\;{\mu}m$.

A Development of Hardware-in-the Loop Simulation System For a Electric Power Steering System (전동식 동력 조향 장치 연구를 의한 HILS 시스템 개발)

  • Park, Dong-Jin;Yun, Seok-Chan;Han, Chang-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.12
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    • pp.2883-2890
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    • 2000
  • In this study, a Hardware-In-The-Loop-Simulation(HILS) system for developing a Electric-Power-Steering(EPS) system is designed. To test a EPS by HILS system, a mathematical vehicle model with a steering system model has been constructed. This mathematical model has been constructed. This mathematical model has been downloaded to the Digital-Signal-Processor(DSP) board. To realize the lateral force acting on the front wheel in a real car. the steering wheel angle sensor and vehicle velocity have been used for input signal. The force sensor has been used for a feedback signal. The full vehicle states could by simulated by the HILS system. Consequently, the HILS system could by used to analyze control-parameters of a EPS that contributes to the maneuverability and stability of a vehicle. At the same time, the HILS system can evaluate the whole performance of the vehicle-steering system. Also the HILS system could do test could not be executed in real vehicle. The HILs system will useful for developing the control logic for the EPS system.

Semi-active control of smart building-MR damper systems using novel TSK-Inv and max-min algorithms

  • Askari, Mohsen;Li, Jianchun;Samali, Bijan
    • Smart Structures and Systems
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    • v.18 no.5
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    • pp.1005-1028
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    • 2016
  • Two novel semi-active control methods for a seismically excited nonlinear benchmark building equipped with magnetorheological dampers are presented and evaluated in this paper. While a primary controller is designed to estimate the optimal control force of a magnetorheological (MR) damper, the required voltage input for the damper to produce such desired control force is achieved using two different methods. The first technique uses an optimal compact Takagi-Sugeno-Kang (TSK) fuzzy inverse model of MR damper to predict the required voltage to actuate the MR dampers (TSKFInv). The other voltage regulator introduced here works based on the maximum and minimum capacities of MR damper at each time-step (MaxMin). Both semi-active algorithms developed here, use acceleration feedback only. The results demonstrate that both TSKFInv and MaxMin algorithms are quite effective in seismic response reduction for wide range of motions from moderate to severe seismic events, compared with the passive systems and performs better than original and Modified clipped optimal controller systems, known as COC and MCOC.

Control of Sound Pressure inside a Flow Excited Cavity by Regulation of Vorticity Shedding (와류진동 조절에 의한 유동가진 공동 내부의 음압 제어)

  • Park, Jong-Beom;Hwang, Cheol-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.12
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    • pp.1223-1229
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    • 2007
  • Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the leading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

Dynamic Threshold Model of Spasticity that Can Predict Various Pendulum Motions (다양한 진자운동을 재현가능한 경직의 동적 역치 모델)

  • Kim Chul-Seung;Kong Se-Jin;Kwon Sun-Duck;Kim Jong-Moon;Eom Gwang-Moon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.7 s.184
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    • pp.152-158
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    • 2006
  • The objective of this work is to develop the knee joint model for representing various pendulum motions and quantifying the spasticity. Knee joint model included the extension and flexion muscles. The joint moment consists of both the active moment from the stretch reflex and the passive moment from the viscoelastic joint properties. The stretch reflex was modeled as nonlinear feedback of muscle length and the muscle lengthening velocity, which is Physiologically-feasible. Moreover, we modeled the spastic reflex as having dynamic threshold to account far the various pendulum trajectories of spastic patients. We determined the model parameters of three patients who showed different pendulum trajectories through minimization of error between experimental and simulated trajectories. The simulated joint trajectories closely matched with the experimental ones, which show the proposed model can predict pendulum motions of patients with different spastic severities. The predicted muscle force from spastic reflex appeared more frequently in the severe spastic patient, which indicates the dynamic threshold relaxes slowly in this patient as is manifested by the variation coefficient of dynamic threshold. The proposed method provides prediction of muscle force and intuitive and objective evaluation of spasticity and it is expected to be useful in quantitative assessment of spasticity.

Wind-Induced Vibration Control of a Tall Building Using Magneto-Rheological Dampers: A Feasibility Study

  • Gu, Ja-In;Kim, Saang-Bum;Yun, Chung-Bang;Kim, Yun-Seok
    • Computational Structural Engineering : An International Journal
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    • v.3 no.1
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    • pp.61-68
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    • 2003
  • A recently developed semi-active control system employing magneto-rheological (MR) fluid dampers is applied to vibration control of a wind excited tall building. The semi-active control system with MR fluid dampers appears to have the reliability of passive control devices and the adaptability of fully active control systems. The system requires only small power source, which is critical during severe events, when the main power source may fail. Numerical simulation studies are performed to demonstrate the efficiency of the MR dampers on the third ASCE benchmark problem. Multiple MR dampers are assumed to be installed in the 76-story building. Genetic algorithm is applied to determine the optimal locations and capacities of the MR dampers. Clipped optimal controller is designed to control the MR dampers based on the acceleration feedback. To verify the robustness with respect to the variation of the external wind force, several cases with different wind forces are considered in the numerical simulation. Simulation results show that the semi-actively controlled MR dampers can effectively reduce both the peak and RMS responses the tall building under various wind force conditions. The control performance of the MR dampers for wind is found to be fairly similar to the performance of an active tuned mass damper.

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A Study on the Development of Mathematical Model of Three-stage Flow Control Valve

  • Khan, Haroon Ahmad;Kang, Chang Nam;Yun, So Nam
    • Journal of Drive and Control
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    • v.15 no.2
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    • pp.38-45
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    • 2018
  • In this study, the theory of fluid mechanics and dynamics is used to build a mathematical model for a three-stage flow control valve. The significance of the study is that the mathematical model can easily be used to study the effect of different design parameters on the performance of the valve. The geometry of the valve and the properties of the fluid were used in this study to determine the variation in the performance of the valve when varying the magnetic force on the pilot spool. While a linearization technique is not used to solve the developed model, the solution of the mathematical model is found in the time domain by simulation of the equations using a software package. The results indicate that if the developed mathematical model is solved for the different values of magnetic force, the valve behaves linearly; the valve is thus called the proportional flow control valve.

An Automatic Speed Control System of a Treadmill with Ultrasonic Sensors (초음파 센서를 이용한 트레드밀의 자동속도 제어시스템)

  • Auralius, Manurung;Yoon, Jung-Won
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.5
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    • pp.505-511
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    • 2011
  • In this paper, we have developed an automatic velocity control system of a small-sized commercial treadmill (belt length of 1.2 m and width of 0.5 m) which is widely used at home and health centers. The control objective is to automatically adjust the treadmill velocity so that the subject's position is maintained within the track when the subject walks at a variable velocity. The subject's position with respect to a reference point is measured by a low-cost sonar sensor located on the back of the subject. Based on an encoder sensor measurement at the treadmill motor, a state feedback control algorithm with Kalman filter was implemented to determine the velocity of the treadmill. In order to reduce the unnatural inertia force felt by the subject, a predefined acceleration limit was applied, which generated smooth velocity trajectories. The experimental results demonstrate the effectiveness of the proposed method in providing successful velocity changes in response to variable velocity walking without causing significant inertia force to the subject. In the pilot study with three subjects, users could change their walking velocity easily and naturally with small deviations during slow, medium, and fast walking. The proposed automatic velocity control algorithm can potentially be applied to any locomotion interface in an economical way without having to use sophisticated and expensive sensors and larger treadmills.