• Title/Summary/Keyword: Position Problem

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A Study on the Position Control of BLDC Motor with New Sliding Surface (새로운 슬라이딩 면을 가지는 BLDC 모터의 위치 제어에 관한 연구)

  • 박수식;이상오;정세교;이대식
    • Proceedings of the KIPE Conference
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    • 1997.07a
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    • pp.84-88
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    • 1997
  • A robust position control system for a BLDC motor using new sliding mode control strategy is presented. Using the new variable structure system, reaching phase problem is eliminated and performance is largely improved. The simulation results show the validity of proposed scheme.

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Measurement of the position and pose of arbitrarily placed polyhedrons (임의로 놓여진 다면체의 위치와 자세측정에 관한 연구)

  • 이상용;한민홍
    • 제어로봇시스템학회:학술대회논문집
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    • 1990.10a
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    • pp.613-617
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    • 1990
  • This paper presents a method of calculating the position and orientation of a polyhedron arbitrarily placed in 3-D space using two cameras. We use key feature of the object and CAD data to solve the correspondence problem between two cameras' images.

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Can Right-Handed Surgeons Insert Upper Thoracic Pedicle Screws in much Comfortable Position? Right-Handedness Problem on the Left Side

  • Akyoldas, Goktug;Senturk, Salim;Yaman, Onur;Ozdemir, Nail;Acaroglu, Emre
    • Journal of Korean Neurosurgical Society
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    • v.61 no.5
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    • pp.568-573
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    • 2018
  • Objective : Thoracic pedicles have special and specific properties. In particular, upper thoracic pedicles are positioned in craniocaudal plane. Therefore, manipulation of thoracic pedicle screws on the left side is difficult for right-handed surgeons. We recommend a new position to insert thoracic pedicle screw that will be much comfortable for spine surgeons. Methods : We retrospectively reviewed 33 patients who underwent upper thoracic pedicle screw instrumentation. In 15 patients, a total of 110 thoracic pedicle screws were inserted to the upper thoracic spine (T1-6) with classical position (anesthesiologist and monitor were placed near to patient's head. Surgeons were standing classically near to patient's body while patients were lying in prone position). In 18 patients, a total of 88 thoracic pedicle screws were inserted to the upper thoracic spine with the new standing position-surgeons stand by the head of the patient and the anesthesia monitor laterally and under patient's belt level. All the operations performed by the same senior spine surgeons with the help of C-arm. Postoperative computed tomography scans were obtained to assess the screw placement. The screw malposition and pedicle wall violations were divided and evaluated separately. Cortical penetration were measured and graded at either : 1-2 mm penetration, 2-4 mm penetration and >4 mm penetration. Results : Total 198 screws were inserted with two different standing positions. Of 198 screws 110 were in the classical positioning group and 88 were in the new positioning group. Incorrect screw placement was found in 33 screws (16.6%). The difference between total screw malposition by both standing positions were found to be statistically significant (p=0.011). The difference between total pedicle wall violations by both standing positions were found to be statistically significant (p=0.003). Conclusion : Right-handedness is a problem during the upper thoracic pedicle screw placement on the left side. Changing the surgeon's position standing near to patient's head could provide a much comfortable position to orient the craniocaudal plane of the thoracic pedicles.

The position control of IM using the binary distrubance observer (바이너리 외란관측기를 이용한 유도전동기의 위치제어)

  • Han, Yoon-Seok;Kim, Young-Seok;Kim, Hyun-Joong;You, Wan-Sik
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2132-2135
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    • 1997
  • A control approch for the robust position control of IM based on the binary disturbance observer is described. The conventional binary observer is used to remove the chattering problem of variable structure system. However the steady state error may be existed, because the conventioal binary observer etimates external disturbance with constant boundary layers. Thus in order to overcome this problem, the improved binary observer is proposed. By employing the proposed observer, the robustness is achived and the continuous control is realized without the chattering problem and the steady state error. The effectiveness of the proposed observer is confirmed by the computer simulation.

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Position Control of An Induction Motor With Chattering Alleviation Sliding Mode Controller (체터링 저감 슬라이딩 모우드 제어기에 의한 유도전동기 위치제어)

  • Kim, Duk-Heon;Kim, Sei-Chan;Yoo, Dong-Wook;Won, Chung-Yeon
    • Proceedings of the KIEE Conference
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    • 1992.07b
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    • pp.1221-1224
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    • 1992
  • To obtain a robustness which is one of important characteristics needed in servo drive, the sliding mode control method is used as a control strategy. However, the undesired phenomenon of chattering is a serious problem. In this paper, an adaptive chattering alleviation algorithm for variable structure system control is proposed to solve this serious problem. Digital controller using the theory of chattering alleviation control is applied to the position control problem of an induction motor system. Comparisons of this algorithm with other variable structure system control algorithms indicate that the chattering can be alleviated. This controller is implemented using IBM-PC(8088 CPU) which controls current controlled PWM inverter consisted of IGBT as a switching device to drive motor.

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Mobile Robot Navigation with Obstacle Avoidance based on the Nonlinear Least Squares Optimization Method using the Cost Function and the Sub-Goal Switching (비용함수와 서브 골을 이용한 비선형 최적화 방법 기반의 이동로봇 장애물 회피 주행)

  • Jung, Young-Jong;Kim, Gon-Woo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.9
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    • pp.1266-1272
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    • 2014
  • We define the mobile robot navigation problem as an optimization problem to minimize the cost function with the pose error between the goal position and the position of a mobile robot. Using Gauss-Newton method for the optimization, the optimal speeds of the left and right wheels can be found as the solution of the optimization problem. Especially, the rotational speed of wheels of a mobile robot can be directly related to the overall speed of a mobile robot using the Jacobian derived from the kinematic model. When the robot detects the obstacle using sensors, the sub-goal switching method is adopted for the efficient obstacle avoidance during the navigation. The performance was evaluated using the simulation and the simulation results show the validity of the proposed method.

A study on distribution system reconfiguration with constant power load using Genetic algorithms (유전알고리즘을 이용한 정전력부하를 갖는 배전계통 선로의 재구성에 관한 연구)

  • Mun, K.J.;Kim, H.S.;Hwang, G.H.;Lee, H.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.11a
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    • pp.71-73
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    • 1995
  • This paper presents an optimization technique using genetic algorithms(GA) for loss minimization in the distribution network reconfiguration. Determining switch position to be opened for loss minimization in the radial distribution system is a discrete optimization problem. GA is appropriate to solve the multivariable optimization problem and it uses population, not a solution. For this reason, GA is attractive to solve this problem. In this paper, we aimed at finding appropriate open sectionalizing switch position using GA, which can lead to minimum transmission losses.

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The Improved Binary Disturbance Observer for the Position Control of Induction Motors (유도전동기의 위치제어를 위한 개선된 바이너리 외란관측기)

  • 한윤석;김영석;김상욱
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.249-254
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    • 1998
  • A control approach for the robust position control of induction motors based on the improved binary disturbance observer is described. The conventional binary disturbance observer is used to remove the chattering problem of a sliding mode disturbance observer. However, the steady state error may be existed in the conventional binary disturbance observer because it estimates external disturbance with a constant boundary layer. In order to overcome this problem, a new binary disturbance observer with an integral augmented switching hyperplane is improved. The robustness is achieved, and the continuous control is realised by employing the improved observer without the chattering problem and the steady state error. The effectiveness of the improved observer is confirmed by the comparative experimental results.

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A Study on distribution system reconfiguration using Genetic algorithms (유전 알고리즘을 이용한 배전계통 선로 재구성에 관한 연구)

  • Mun, K.J.;Kim, H.S.;Hwang, G.H.;Lee, H.S.;Park, J.H.
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.488-490
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    • 1995
  • This paper presents an optimization technique using genetic algorithms(GA) for loss minimization in the distribution network reconfiguration. Determining switch position to be opened for loss minimization in the radial distribution system is a discrete optimization problem. GA is appropriate to solve the multivariable optimization problem and it uses population, not a solution. For this reason, GA is attractive to solve this problem. In this paper, we aimed at finding appropriate open sectionalizing switch position using GA, which can lead to minimum transmission losses.

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Navigation of a Mobile Robot Using Nonlinear Least Squares Optimization (비선형 최적화 방법을 이용한 이동로봇의 주행)

  • Kim, Gon-Woo;Cha, Young-Youp
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.7
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    • pp.1404-1409
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    • 2011
  • The fundamental research for the mobile robot navigation using the numerical optimization method is presented. We define the mobile robot navigation problem as an unconstrained optimization problem to minimize the cost function with the pose error between the goal position and the position of a mobile robot. Using the nonlinear least squares optimization method, the optimal speeds of the left and right wheels can be found as the solution of the optimization problem. Especially, the rotational speed of wheels of a mobile robot can be directly related to the overall speed of a mobile robot using the Jacobian derived from the kinematic model. It will be very useful for applying to the mobile robot navigation. The performance was evaluated using the simulation.