• Title/Summary/Keyword: Initial angular velocity

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Dubins Path Generation and Tracking of UAVs With Angular Velocity Constraints (각속도 제한을 고려한 무인기의 Dubins 경로 생성 및 추적)

  • Yang, You-young;Jang, Seok-ho;Leeghim, Henzeh
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.49 no.2
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    • pp.121-128
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    • 2021
  • In this paper, we propose a path generation and tracking algorithm of an unmanned air vehicle in a two-dimensional plane given the initial and final points. The path generation algorithm using the Dubins curve proposed in this work has the advantage that it can be applied in real time to an unmanned air vehicle. The path tracking algorithm is an algorithm similar to the line-of-sight induction algorithm. In order to efficiently control the direction angle, a gain related to the look ahead distance concept is introduced. Most of UAVs have the limited maximum curvature due to the structural constraints. A numerical simulation is conducted to follow the path generated by the sliding mode controller considering the angular velocity limit. The path generation and tracking performance is verified by comparing the suggested controller with conventional control techniques.

Design and Meshing Analysis of a Non-involute Internal Gear for Counters (계수기용 비인벌류트 치형의 내치차 설계와 물림해석)

  • Lee, Sung-Chul
    • Tribology and Lubricants
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    • v.30 no.4
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    • pp.212-217
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    • 2014
  • A counter gear transmits the rotation angle, so the angular velocity ratio of the gear does not necessarily need to be constant in the meshing process. As a pinion has a small number of teeth when combined with an internal gear for counters, tooth interference can occur with the use of an involute curve. This paper introduces circular arcs that represent a tooth profile and fillet for the profile design of a pinion through the combination of arcs with lines. The straight line of a rack tooth represents the profile of a mating internal gear. Thus, the circular arc and line maintain contact during the rotation of the counter gear. This paper presents an analysis of the meshing of the circular arc tooth and rack tooth along with the properties of the counter gear, such as the change in rotational velocity and amount of backlash. The contact ratio of the counter gear is 1 because the tooth contact occurs between circular arcs and line. The initial position of tooth contact, which denotes the simultaneous contact of two teeth, is found. As the rotation of the pinion, only one tooth keeps the contact situation. This meshing property is analyzed by the geometrical constraints of the tooth profile in contact and the results are presented as graphical diagrams in which tooth-arc movements are superimposed.

A study on automation of crane operation (천정 크레인의 자동화 연구)

  • 박병석;김성현;윤지섭
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.1871-1875
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    • 1997
  • Crane operation is manually accomplished by skilled operators. Recently, the concept of automation is widely introduced in shipping and unloading operation using the overhead crane for the enhanced productivity. In this regards, we designed an angle detector and 3D position detectro which are key evices for this operation. As well as an intellignet control algorithm is developed for the implementation of swing free crane. The performance of the presented algorithm is tested for the swing angle and the position of the overheas crand. The control scheme adopts a feedback control of an angular velocity of swing in initial phase and then the fuzzy controller whose rule base is optimized by a genetic algorithm.

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Improving Finger-click Recognition of a Wearable Input Device

  • Soh, Byung-Seok;Kim, Yoon-Sang;Lee, Sang-Goog
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.72-75
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    • 2004
  • In this paper, a finger-click recognition method is proposed to improve the recognition performance for finger-clicking of a wearable input device, called $SCURRY^{TM}$. The proposed method is composed of three parts including feature extraction part, valid click discrimination part, and cross-talk avoidance part. Two types of MEMS inertial sensors are embedded into the wearable input device to measure the angular velocity of a hand (hand movement) and the acceleration rates at the ends of fingers (finger-click motion). The experiment applied to the $SCURRY^{TM}$ device shows the improved stability and performance.

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Transient Characteristics of Separately Excited d-c Motor Driven by Thyristor d-c Chopper (Thyristor 직류 Chopper방식으로 구동되는 직류타여자식 전동기의 과도특성해석법)

  • Hee Young Chun
    • 전기의세계
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    • v.21 no.2
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    • pp.9-19
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    • 1972
  • The transient characteristics of separately excited d-c motor driven by thyristor d-c chopper is studied in this paper. The armature controlled system is applied. As a result of theoretrical analysis the following conculsions were drawn: (1) For the transient analysis, it is recognized that the state transition analysis is a more general method and powerful tool than the state equation method or signal flow graph method, although it includes iterative matrix calculations. And the system is dealt with a finite width sampled-data system in the state transition analysis. (2) The transient characteristics of the motor angular velocity and its torque to the sampling duration variation are compared with those due to the amplitude variation of d-c chopper voltage as follows. The attenuation rate of the transient characteristics is equal in both cases, but the initial value of the transient characteristics in former case is greater than in latter case. (3) The roots of characteristics equation of the system lie inside the unit circle of the Z-plane. Therefor the system is stable. Further it is found that as the sampling duration is decreased the relative stability is lessened.

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Output Feedback Sliding Mode Control System with Disturbance Observer for Rotational Inverted Pendulums (외란 관측기를 이용한 회전형 역진자 시스템의 출력 피드백 슬라이딩 모드 제어)

  • Lee, Gyu-Jun;Ha, Jong-Heon;Kim, Jong-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.2
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    • pp.243-253
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    • 2002
  • This paper presents the system modeling, analysis, and controller design and implementation for a rotational inverted pendulum system(RIPS), which is an under-actuated system and has the problem of unattainable angular velocity state. A sliding mode controller using the parameterization of both the hyperplane and the compensator fur output feedback is applied to the RIPS. Also, to improve the performance of the control system, a disturbance observer which estimates the disturbance, parameter variation, and some modeling errors of RIPS with less computational effort is used together. The results of simulation and experiment show that the proposed control system has superior performance for disturbance rejection and regulation at certain initial conditions.

Multimachine Stabilizer using Sliding Mode Observer-Model Following including CLF for Measurable State Variables

  • Lee, Sang-Seung;Park, Jong-Keun
    • Journal of Electrical Engineering and information Science
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    • v.2 no.4
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    • pp.53-58
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    • 1997
  • In this paper, the power system stabilizer(PSS) using the sliding mode observer-model following(SMO-MF) with closed-loop feedback (CLF) for single machine system is extended to multimachine system. This a multimachine SMO-MF PSS for unmeasureable plant state variable is obtained by combining the sliding mode-model following(SM-MF) including closed-loop feedback(CLF) with the full-order observer(FOO). And the estimated control input for unmeasurable plant sate variables is derived by Lyapunov's second method to determine a control input that keeps the system stable. Time domain simulation results for the torque angle and for the angular velocity show that the proposed multimachine SMO-MF PSS including CLF for unmeasurable plant sate variables is able to damp out the low frequency oscillation and to achieve asymptotic tracking error between the reference model state at different initial conditions and at step input.

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Modelling of Swimming Ability Limits for Marine Fish

  • KIM Yong-Hae;WARDLE Clement S.
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.6
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    • pp.929-935
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    • 1997
  • The total energy of fish movement and the maximum burst swimming speed were estimated and formulated in accordance with body length and water temperature for several species in fisheries by empirical methods and also by using published results. Under the assumption of swimming energy reserve of a fish at the initial rest state, the swimming endurance of fish with different body lengths, swimming speeds and angular velocity was calculated using the relevant equations under similar conditions in tank experiments as well as natural conditions in field. Relative swimming energy efficiency or the transition swimming speed between red and white muscle for energy consumption was represented as a trigonometric function of swimming speed ratio. Therefore, this model does closely approach the actual swimming abilities and their limits especially in relation to the fishing gear operation and allow for the greater vitality of the wild fish in the fields.

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A New Approach for SINS Stationary Self-alignment Based on IMU Measurement

  • Zhou, Jiangbin;Yuan, Jianping;Yue, Xiaokui
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.355-359
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    • 2006
  • For the poor observability of azimuth misalignment angle and east gyro drift rate of the traditional initial alignment, a bran-new SINS stationary fast self-alignment approach is proposed. By means of analyzing the characteristic of the strapdown inertial navigation system (SINS) stationary alignment seriously, the new approach takes full advantage of the specific force and angular velocity information given by inertial measurement unit (IMU) instead of the mechanization of SINS. Firstly, coarse alignment algorithm is presented. Secondly, a new fine alignment model for SINS stationary self-alignment is derived, and the observability of the model is analysed. Then, a modified Sage-Husa adaptive Kalman filter is introduced to estimate the misalignment angles. Finally, some computer simulation results illustrate the efficiency of the new approach and its advantages, such as higher alignment accuracy, shorter alignment time, more self-contained and less calculation.

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Design of Ship's Steering System by Introducting the Improved Fuzzy Logic (새로운 Fuzzy Logic을 이용한 선박조타계의 제어)

  • 이철영;채양범
    • Journal of the Korean Institute of Navigation
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    • v.8 no.1
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    • pp.15-42
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    • 1984
  • Many studies have been done in the field of fuzzy logic theory, but it's application to the ship's steering system is few until this date. This paper is to survey the effect of application of fuzzy logic control by new compositional rule of Inference to the ship's steering system. The controller is made up of a set of Linguistic Control Rules which are conditional linguistic statements connecting the inputs and output, and take the inputs derived from deviation angle and it's angular velocity. The Linguistic Control Rules are implemented on the digital computer to verify the performance of the fuzzy logic controller and simulations have been done in six cases of initial condition and disturbance type. Consequently, it was proved that the ship's steering system by introducing the F.L.C. is performed efficiently and less energy loss system compared with the conventional autopilot.

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