• Title/Summary/Keyword: Servo-motor

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Servo Motor Control by On-Off Controller with Hysterisis (히스테리시스를 갖는 온-오프 제어기에 의한 서보모터의 제어)

  • 김영복;김성환;양주호;정병건
    • Journal of Advanced Marine Engineering and Technology
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    • v.15 no.1
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    • pp.85-95
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    • 1991
  • All physical systems are nonlinear to some degree. The examples are relay, backlash, deadzone, saturation element and so on. In the linear control system design, it is useful method to restrict the nonlinearity to the linearity of system over the operation range. It is worth noting that nonlinearities may be intentionally introduced in to a system. A simple of an intentional non-linearity is the Bang-Bang controller which uses the On-Off relay. In this paper, an angular position servosystem made of a DC servomotor controlled by a microcomputer is discribed. Authors use two methods in the design of controller. The one is linear controller designed by the optimal feedback control theory only and the other is nonlinear controller designed by On-Off relay with optimal feedback control theory. To do the real time control, the controller is designed by using 16bit personal computer and A/D.D/A converter(12bit) is used in order to convert the signal. According to this way, the results from real time control are as follows. 2) Under the On-Off controller with hysterisis the influence of disturbance is considerably smaller than the linerar controller. 3) An increase in the sampling period has a destabilizing effect. 4)In the controller performance, the response time of the On-Off controller is longer than that of the linear controller. To close, we note that the On-Off controller with hysterisis is more attractive than the linear controller in the presence of the input limit.

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A Study on Structural Design and Evaluation of the High Precision Cam Profile CNC Grinding Machine (고 정밀 캠 프로파일 CNC 연삭기의 구조설계 및 평가에 관한 연구)

  • Lim, Sang-Heon;Shin, Sang-Hun;Lee, Choon-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.10
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    • pp.113-120
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    • 2006
  • A cam profile CNC grinding machine is developed for manufacture of high precision contoured cams. The developed machine is composed of the high precision spindle using boll bearings, the high stiffness box layer type bed and the three axis CNC controller with the high resolution AC servo motor. In this paper, structural and modal analysis for the developed machine is carried out to check the design criteria of the machine. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. The machine is modeled by placing proper shell and solid finite elements. And also, this paper presents the measurement system and experimental investigation on the modal analysis of a grinding machine. The weak part of the machine is found by the experimental evaluation. The results provide structure modification data for good dynamic behaviors. And safety of the machine was confirmed by the modal analysis of modified machine design. Finally, the cam profile grinding machine was successfully developed.

Development of a Vegetable Transplanting Robot

  • Kang, Dong-Hyeon;Kim, Dong-Eok;Lee, Gong-In;Kim, You-Ho;Lee, Hye-Jin;Min, Young-Bong
    • Journal of Biosystems Engineering
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    • v.37 no.3
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    • pp.201-208
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    • 2012
  • Purpose: This study was conducted to develop a vegetable transplanting robot which transplants seedlings from a nursery tray to a plant pot using its four fingers. Method: The robot consists of the transplanting part, nursery tray moving part, plant pot moving part, main frame and controller. Two moving parts are controlled by the photo sensor and servo motor. The transplanting part was composed with two components; transporting device using E-MY2H(SMC Corp., Japan) for controlling finger position accurately and finger for transplanting the seedling. Results: Head lettuce using the transplanting robot was transplanted in 21 days after sowing based upon the seed shape measurement and removing examination. The optimal finger shape was thin pin type because it caused minimum damage to the roots of seedlings. Conclusions: The four inclined pin type was applied to remove the seedlings from the nursery tray. In addition, the transplanting capacity of the developed robot was 2800 pots per hour and the rate of success was 99% and above.

A Study on The Actual Application of the Least Order Load Observer and Effective Online Inertia Identification Algorithm for High Performance Linear Motor Positioning System (고성능 선형전동기 위치제어 시스템에 대한 최소차원 부하관측기의 실제적 구현 및 이를 이용한 실시간 관성추정기의 구현)

  • Kim, Joohn-Sheok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.4
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    • pp.730-738
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    • 2007
  • As well known when the linear machine is operated between two points repeatedly under positioning control, there are various positioning error at the moment of zero speed owing to the non-linear disturbance like as unpredictable friction force. To remove this positioning error, a simple least order disturbance observer is introduced and is actually implemented in this study. Due to this simple algorithm the over-all machine system can be modified to simple arbitrary given one-mass load without any disturbance. So, the total construction process for positioning control system is much easier than old one. Moreover, to generate a proper effective position profile with the limited actual machine force, a very powerful on-line mass identification algorithm using the load force estimator is presented. In the proposed mass identification algorithm, the exact load mass can be calculated during only one moving stage under a normally generated position profile. All presented algorithm is verified with experimental result with commercial linear servo machine system.

Passive, semi-active, and active tuned-liquid-column dampers

  • Chen, Yung-Hsiang;Ding, Ying-Jan
    • Structural Engineering and Mechanics
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    • v.30 no.1
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    • pp.1-20
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    • 2008
  • The dynamic characteristics of the passive, semi-active, and active tuned-liquidcolumn dampers (or TLCDs) are studied in this paper. The design of the latter two are based on the first one. A water-head difference (or simply named as water head in this paper) of a passive TLCD is pre-set to form the so-called semi-active one in this paper. The pre-set of water head is released at a proper time instant during an earthquake excitation in order to enhance the vibration reduction of a structure. Two propellers are installed along a shaft inside and at the center of a passive TLCD to form an active one. These two propellers are driven by a servo-motor controlled by a computer to provide the control force. The seismic responses of a five-story shear building with a passive, semiactive, and active TLCDs are computed for demonstration and discussion. The responses of this building with a tuned mass damper (or TMD) are also included for comparison. The small-scale shaking-table experiments of a pendulum-like system with a passive or active TLCD to harmonic and seismic excitations are conducted for verification.

An Experimental Study about Tractive Performance of Tracked Vehicle on Deep-sea Soft Sediment Based on Design of Experiment Using Orthogonal Array (직교배열표 실험계획법에 의한 심해 연약지반용 무한궤도차량의 견인성능에 대한 실험적 연구)

  • Choi, Jong-Su;Hong, Sup;Kim, Hyung-Woo;Lee, Tae-Hee
    • Ocean and Polar Research
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    • v.26 no.2
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    • pp.333-339
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    • 2004
  • This paper is concerned with an experimental investigation about tractive performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of $0.9\;m(L)\;{\times}\;0.75\;m(B)\;{\times}\;0.4\;m(H)$ and the weight of 167 kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of $6.0\;m(L)\;{\times}\;3.7\;m(B)\;{\times}\;0.7\;m(H)$. Slip of vehicle and driving torque of motor were measured with respect to experimental variables; grouser span, grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. $L_8$ orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables on traction performance are evaluated.

Making for Circular Motion Table for Controller Design of Movement of Object (운동 물체의 제어기 설계를 위한 3축 가변 원판형 모션테이블 제작)

  • You, Jeong-Bong;Wang, Hyun-Min
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.4
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    • pp.905-910
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    • 2008
  • In this paper, a circular motion table which is able to simulate movement of object is designed and the experiment of control system using circular motion table is presented. Circular motion table is consisted of three axes changed on length and of ball splines which keep vertical centre axis of circular plate. Variable length of three axes make circular plate incline as vertical centre axis is kept on vertical center axis of circular motion table. It is designed that control system drives three servo motor, that is, make change length of axis simultaneously or independently. And this paper presents example of flight simulation using circular motion table. it will contribute toward nurture expert manpower of aerospace/robotics to popularize circular motion table and make an experiment using it.

Auto plant control system by using Arduino

  • Chowdhury, Deb
    • Korean Journal of Artificial Intelligence
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    • v.1 no.1
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    • pp.4-6
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    • 2013
  • In the era of information society, IT industry has been developed very much. New technology has made appearance in citizens' lives. IOT (Internet of Things) has grown up the most rapidly in IT industry. Kevin Ashiton, MIT specialist, said, "Loading of FRIS and other sensors shall build Internet of things." Internet of things is said to let things have sensor and communication module and to exchange information and communicate each other. In this study, Internet of things has been applied to flowerpot to build automatic flowerpot control system that turns fan ON and supplies water depending upon temperature and moisture. Users are difficult to cognize temperature and humidity of flower pot correctly. In this study, an experiment obtained correct value of temperature and humidity to build control system. At the performance test of flower pot, commands turned ON depending upon temperature and humidity. Control system should be added to control water supply quantity and time objectively according to servo motor control. Purpose of further study was to control flower pot by remote system in connection with smart phone application. An application control can make not only temperature and humidity statistics but also server depending upon users' needs to turn fan ON and take actions and to control flower pot.

Aerodynamic Characteristics of a Variable Span Wing Flying Inside a Channel I (Effects of Wing Aspect Ratio and Guideway) (채널 내를 비행하는 가변스팬 날개 공력특성 I (가로세로비 및 안내로 영향))

  • Han, Cheolheui
    • Journal of Aerospace System Engineering
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    • v.10 no.4
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    • pp.11-16
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    • 2016
  • In this paper, an experimental study on the aerodynamic characteristics of a variable span wing flying inside a channel guideway is accomplished using wind tunnel testing. A variable span wing with a NACA 0012 airfoil section was fabricated and actuated using a linear servo motor. The aerodynamic effects of 1) wing aspect ratio, 2) ground effect, and 3) the gap between the wingtip and the wing fence were investigated. It was found that both ground effect and wing fence gap increased lift. Also, the wing fence gap does not significantly affect drag. Therefore, it was found that a variable span mechanism can be used as an effective high lift device when flap use is limited.

A Study on Tracking Control of an Industrial Overhead Crane Using Sliding Mode Controller (슬라이딩모드 제어기를 이용한 산업용 천정크레인의 추종제어에 관한 연구)

  • Park, Byung-Suk;Yoon, Ji-Sup;Kang, E-Sok
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.11
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    • pp.1022-1032
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    • 2000
  • We propose a sliding mode controller tracking the states of a time-varying reference model. The reference model generates the desired trajectories of the states, and the sliding mode controller regulates robustly the errors between the desired states and the measured states. We apply this controller to the overhead crane. Its reference model generates the trajectories of the damped-out swing angle and the swing angular velocity to suppress the swinging motion caused by the acceleration and the deceleration of crane transportation. Also, this model generates the desired trajectories of the position and velocity of the crane. The crane model is identified from the experimental data using an orthogonal function. Kalman filtering is applied to estimate the crane states. The designed controller is simulated on a computer and is tested through a 2-ton industrial overhead crane using the vector-controlled servo motor system. It is verified that, from the simulated and experimental results, the sliding mode controller tracking a time-varying reference model works well.

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