• Title/Summary/Keyword: Torque Disturbance

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Unscented KALMAN Filtering for Spacecraft Attitude and Rate Determination Using Magnetometer

  • Kim, Sung-Woo;Abdelrahman, Mohammad;Park, Sang-Young;Choi, Kyu-Hong
    • Journal of Astronomy and Space Sciences
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    • v.26 no.1
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    • pp.31-46
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    • 2009
  • An Unscented Kalman Filter (UKF) for estimation of the attitude and rate of a spacecraft using only magnetometer vector measurement is developed. The attitude dynamics used in the estimation is the nonlinear Euler's rotational equation which is augmented with the quaternion kinematics to construct a process model. The filter is designed for small satellite in low Earth orbit, so the disturbance torques include gravity-gradient torque, magnetic disturbance torque, and aerodynamic drag torque. The magnetometer measurements are simulated based on time-varying position of the spacecraft. The filter has been tested not only in the standby mode but also in the detumbling mode. Two types of actuators have been modeled and applied in the simulation. The PD controller is used for the two types of actuators (reaction wheels and thrusters) to detumble the spacecraft. The estimation error converged to within 5 deg for attitude and 0.1 deg/s for rate respectively when the two types of actuators were used. A joint state parameter estimation has been tested and the effect of the process noise covariance on the parameter estimation has been indicated. Also, Monte-Carlo simulations have been performed to test the capability of the filter to converge with the initial conditions sampled from a uniform distribution. Finally, the UKF performance has been compared to that of the EKF and it demonstrates that UKF slightly outperforms EKF. The developed algorithm can be applied to any type of small satellites that are actuated by magnetic torquers, reaction wheels or thrusters with a capability of magnetometer vector measurements for attitude and rate estimation.

Sliding Mode Control for an Electric Power Steering System in an Autonomous Lane Keeping System (자동 차선 유지 시스템의 전기식 파워 조향 시스템을 위한 슬라이딩 모드 제어기)

  • Yu, Jun Young;Kim, Wonhee;Son, Young Seop;Chung, Chung Choo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.2
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    • pp.95-101
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    • 2015
  • In this paper, we develop a sliding mode control for steering wheel angle control based on torque overlay in order to resolve the problem of previous methods for Electric Power Steering (EPS) systems in the Lane Keeping System (LKS) of autonomous vehicles. For the controller design, we propose a 2nd order model of the electric power steering system in an autonomous LKS. The desired state model is designed to prevent a rapid change of the steering wheel angle. The sliding mode steering wheel angle controller is developed for the robustness of the disturbance. Since the proposed method is designed based on torque overlay, torque integration with basic functions of the EPS system for the steering wheel angle control is available for the driver's convenience. The performance of the proposed method was validated via experiments.

A study on the thrust force and torque calculation models in the design of shield TBM (쉴드 TBM 설계 시 추력과 토크 산정식들에 대한 고찰)

  • Chong, Song-Hun;Lee, Seung-Hun;Ryu, Hee-Hwan;Kim, Hun-Tae
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.3
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    • pp.219-237
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    • 2020
  • Rapid economic development and urban population growth have been increasing the necessity for underground space exploration and utilization due to the need of upgrading and expanding the existing infrastructures. TBM has been widely used to construct underground structures with high advance rate and minimal ground disturbance. Two important design parameters, which are available thrust capacity and cutterhead torque, should be estimated for any project in addition to proper selection of TBM type. However, the conventional thrust force and torque estimation model only depends on the empirical equation, which hinders the design process of the optimal thrust hydraulic system and the appropriate hydraulic components. In this study, four thrust and torque calculation models are derived and explained. For TBM design practice, the four estimation models are compared and discussed.

Development of High Precision Fastening torque performance Nut-runner System (고정밀 체결토크 성능 너트런너 시스템 개발)

  • Kim, Youn-Hyun;Kim, Sol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.35-42
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    • 2019
  • Nut fasteners that require ultra-precise control are required in the overall manufacturing industry including electronic products that are currently developing with the automobile industry. Important performance factors when tightening nuts include loosening due to insufficient fastening force, breakage due to excessive fastening, Tightening torque and angle are required to maintain and improve the assembling quality and ensure the life of the product. Nut fasteners, which are now marketed under the name Nut Runner, require high torque and precision torque control, precision angle control, and high speed operation for increased production, and are required for sophisticated torque control dedicated to high output BLDC motors and nut fasteners. It is demanded to develop a high-precision torque control driver and a high-speed, low-speed, high-response precision speed control system, but it does not satisfy the high precision, high torque and high speed operation characteristics required by customers. Therefore, in this paper, we propose a control technique of BLDC motor variable speed control and nut runner based on vector control and torque control based on coordinate transformation of d axis and q axis that can realize low vibration and low noise even at accurate tightening torque and high speed rotation. The performance results were analyzed to confirm that the proposed control satisfies the nut runner performance. In addition, it is confirmed that the pattern is programmed by One-Stage operation clamping method and it is tightened to the target torque exactly after 10,000 [rpm] high speed operation. The problem of tightening torque detection by torque ripple is also solved by using disturbance observer Respectively.

High Speed Precision Control of Mobile Robot using Neural Network in Real Time (신경망을 이용한 이동 로봇의 실시간 고속 정밀제어)

  • 주진화;이장명
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.1
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    • pp.95-104
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    • 1999
  • In this paper we propose a fast and precise control algorithm for a mobile robot, which aims at the self-tuning control applying two multi-layered neural networks to the structure of computed torque method. Through this algorithm, the nonlinear terms of external disturbance caused by variable task environments and dynamic model errors are estimated and compensated in real time by a long term neural network which has long learning period to extract the non-linearity globally. A short term neural network which has short teaming period is also used for determining optimal gains of PID compensator in order to come over the high frequency disturbance which is not known a priori, as well as to maintain the stability. To justify the global effectiveness of this algorithm where each of the long term and short term neural networks has its own functions, simulations are peformed. This algorithm can also be utilized to come over the serious shortcoming of neural networks, i.e., inefficiency in real time.

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Precision Position Control of Induction Motors Using Disturbance Observer (외란관측기를 이용한 유도전동기의 정밀 위치 제어)

  • Kim, Hyun-Sik;Kang, Kyoung-Woo;Ko, Jong-Sun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.11 no.1
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    • pp.38-45
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    • 2006
  • This paper presents load torque observer that is used to deadbeat control method in the induction motor(IM) precision position control system. The proposed algorithm shows robustness on induction servo motor system. All of the gain has been obtained on discrete domain analysis. The simulation has been obtained by the simulink. The results show that proposed system has good effectiveness for the disturbance of the induction servo motor system using DS1102 board.

Vehicle Shudder Associated with Axial Thrust Force of C.V.Joint For Automobile (자동차용 등속조인트의 AXIAL FORCE와 VEHICLE SHUDDER(I))

  • 오승탁
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.2
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    • pp.198-208
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    • 1996
  • The plunge joints of C.V. Joint for vehicle tend to produce a cyclic axial disturbance at a frequency of three of six times shaft speed, in which this distrubance caused by internal frictional effect is related to joint angle, rotational speed, torque, and joint size. This principal axial thrust force might make vehicle shuddered when coinciding with vehicle frequency of tranverse direction, and be one of reasons to have driver feel uncomfortable, unesay, while driving vehicle. The paper makes analysis of axial thrust force & vehicle shudder through computer simulation, comparing the result with experimental data, and reviewing the effect by changing of variables such as dimensions and driving conditions.

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A STUDY OF ROBUST CONTROLLER FOR ROBOT MANIPULATOR (로보트 매니플레이터의 제어를 위한 강인한 적응 제어기의 설계)

  • Park, Kyoung-Hee;Hong, Suk-Kyo
    • Proceedings of the KIEE Conference
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    • 1989.11a
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    • pp.450-455
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    • 1989
  • In this paper we investigate the application to the motion control of n-link robotic manipulators of recently developed stable factorization approach to tracking and disturbance rejection. Given control scheme consists of an approximate "Computed Torque" based upon a simplified model together with additional state feedback and feedforward compensation, and then, nonlinear control gain has more useful than constant control gain to guarantee robustness to parameter uncertainty and external disturbance. At this stage, we design high gain nonlinear state feedback controller and simulate this controller at the SCARA type robot manipulator of two joint.

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Design of an Adaptive Speed Controller for Induction Motors Using Nonlinear Disturbance Observer (비선형 외란 관측기를 이용한 유도전동기의 적응 속도제어기 설계)

  • Hwang, Young-Ho;Lee, Sun-Young;Chung, Kee-Chull;Han, Byoung-Jo;Yang, Hai-Won
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1509-1510
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    • 2008
  • In this paper, we propose a robust adaptive controller for induction motors with uncertainties using nonlinear disturbance observer(NDO). The proposed NDO is applied to estimate the time varying lumped uncertainty which are derived from unknown motor parameters and load torque, but NDO error does not converge to zero since the derivate of lumped uncertainty is not zero. Then the high order neural networks(HONN) is presented to estimate the NDO error such that the rotor speed to converge to a small neighborhood of the desired trajectory. Rotor flux and inverse time constant are estimated by the sliding mode adaptive flux observer. Simulation results are provided to verify the effectiveness of the proposed approach.

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Robust PID Controller Design for Speed Control of BLDC Motors (BLDC 모터 속도제어를 위한 견실 PID 제어기 설계)

  • 양승윤;김인수;전완수
    • Journal of the Korea Institute of Military Science and Technology
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    • v.5 no.1
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    • pp.75-82
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    • 2002
  • In this paper, the robust PID(Proportional-Integral-Derivative) controller was designed for speed control of BLDC motors using the frequency region model matching method. It was designed the robust PID controller satisfying disturbance attenuation and robust tracking performance using an H$\infty$ control method. The robust PID controller gains with the performances of the designed H$\infty$ controller are determined using the model matching method at frequency domain. Consequently, simulation results show that the proposed PID speed controller satisfies load torque disturbance attenuation and robust tracking performance, and this study has usefulness and applicability for the speed control system design of BLDC motors.