• Title/Summary/Keyword: Optimal velocity

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Optimal Optical Mouse Array for High Performance Mobile Robot Velocity Estimation (이동로봇 속도 추정 성능 향상을 위한 광 마우스의 최적 배열)

  • Kim, Sungbok;Kim, Hyunbin
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.6
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    • pp.555-562
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    • 2013
  • This paper presents the optimal array of optical mice for the accurate velocity estimation of a mobile robot. It is assumed that there can be some restriction on the installation of two or more optical mice at the bottom of a mobile robot. First, the velocity kinematics of a mobile robot with an array of optical mice is derived, which maps the velocity of a mobile robot to the velocities of optical mice. Second, taking into account the consistency in physical units, the uncertainty ellipsoid is obtained to represent the error characteristics of the mobile robot velocity estimation owing to noisy optical mouse measurements. Third, a simple but effective performance index is defined as the inverse of the volume of the uncertainty ellipsoid, which can be used for the optimization of the optimal optical mouse placement. Fourth, simulation results for the optimal placement of three optical mice within a given elliptical region are given.

Study on the Optimal Velocity of Horizontal Air Jet of a Range hood system (주방용 후드 수평급기의 최적속도 결정에 관한 연구)

  • Kim, Sang-Gyu;Park, Sung-Geun;Yong, Ho-Taek;Kim, Dong-Yoon;Choi, Hyoung-Gwon
    • Proceedings of the SAREK Conference
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    • 2005.11a
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    • pp.63-68
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    • 2005
  • In the present paper, the study on the optimal horizontal air jet velocity of a range hood system has been studied by three dimensional numerical simulation. It has been shown that the air jet of a range flood system generates coanda effect confining the contaminated (high temperature) air in a certain region while the jet pushes out more contaminated air into a room as the jet velocity increases. Therefore, the optimal jet velocity has been determined by the combination of the two mechanism.

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Analysis of Optimal Landing Trajectory in Attitude Angular Velocity Influence at Powered Descent Phase of Robotic Lunar Lander (무인 달착륙선의 동력하강단계에서 자세각속도 영향에 따른 최적화 착륙궤적 분석)

  • Park, Jae-ik;Rew, Dong-Young
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.46 no.5
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    • pp.402-409
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    • 2018
  • In this paper, we propose a lunar landing scenario of a robotic lunar landing mission and implements an optimal landing trajectory at the powered descent phase based on the proposed scenario. The change of attitude of the lunar lander in the power descent phase affects not only the amount of fuel used but also sensor operation of image based navigation. Therefore, the attitude angular velocity is included in the cost function of the optimal control problem to minimize the unnecessary attitude change when the optimal landing trajectory generates at powered descent phase of the lunar landing. The influence of the change of attitude angular velocity on the optimal landing trajectory are analyzed by adjusting the weight of the attitude angular velocity. Based on the results, we suggest the proper weight to generate the optimal landing trajectory in order to minimize the influence of the attitude angular velocity.

Optimal Control of Speed Regulating Systems (속도제어를 대상으로 하는 계통의 최적제어)

  • 양흥석;이종호
    • 전기의세계
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    • v.28 no.2
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    • pp.55-60
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    • 1979
  • In this paper, a new method of the optimal control of the regulator and tracking control problem concerning the dimension of the velocity is derived and applied for the second order plant. The output position, output velocity and the control effort are plottcd with time applying analog computer simulation. And it is compared with the output of the ordinary optimal control law in case the reference input is given by velocity function, and studied about the gain of this method.

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Inverse Optimal Design of Formation/Velocity Consensus Protocol for Mobile Robots Based on LQ Inverse Optimal Second-order Consensus (LQ-역최적 2차 일치제어에 기반한 이동로봇에 대한 대형·속도일치 프로토콜의 역최적 설계)

  • Lee, Jae Young;Choi, Yoon Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.5
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    • pp.434-441
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    • 2015
  • In this paper, we propose an inverse optimal distributed protocol for the formation and velocity consensus of nonholonomic mobile robots. The communication among mobile robots is described by a simple undirected graph, and the mobile robots' kinematics are considered. The group of mobile robots driven by the proposed protocols asymptotically achieves the desired formation and group velocity in an inverse optimal fashion. The design of the protocols is based on dynamic feedback linearization and the proposed linear quadratic (LQ) inverse optimal second-order consensus protocol. A numerical simulation is given to verify the effectiveness of the proposed scheme.

A Study on the Optimal Frequency for Precise Measurement of Fracture Velocity by Ultrasonic Fractography (초음파 Fractography에 의한 파괴속도의 첨밀측정을 위한 최적주파수 선정에 관한 연구)

  • Lee, B.S.;Han, E.K.;Song, C.S.
    • Journal of the Korean Society for Precision Engineering
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    • v.10 no.2
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    • pp.154-160
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    • 1993
  • A mothod to decide the optimal frequency for the fracture velocity measurement by ultrasonic fractography is presented. A theoretical formula to decide the optimal frequency for ultrasonic fractography testing is made and it is compared with experimental value. According to the formula the optimal frequency is shown to be depending on the attenuation coefficient and size(width) of the specimen. In the case of PMA specimen with ligament 43mm the theoretical value for the optimal frequency is about 260 KHz and it is good agreement with experimental value.

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Intelligent Optimal Route Planning Based on Context Awareness (상황인식 기반 지능형 최적 경로계획)

  • Lee, Hyun-Jung;Chang, Yong-Sik
    • Asia pacific journal of information systems
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    • v.19 no.2
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    • pp.117-137
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    • 2009
  • Recently, intelligent traffic information systems have enabled people to forecast traffic conditions before hitting the road. These convenient systems operate on the basis of data reflecting current road and traffic conditions as well as distance-based data between locations. Thanks to the rapid development of ubiquitous computing, tremendous context data have become readily available making vehicle route planning easier than ever. Previous research in relation to optimization of vehicle route planning merely focused on finding the optimal distance between locations. Contexts reflecting the road and traffic conditions were then not seriously treated as a way to resolve the optimal routing problems based on distance-based route planning, because this kind of information does not have much significant impact on traffic routing until a a complex traffic situation arises. Further, it was also not easy to take into full account the traffic contexts for resolving optimal routing problems because predicting the dynamic traffic situations was regarded a daunting task. However, with rapid increase in traffic complexity the importance of developing contexts reflecting data related to moving costs has emerged. Hence, this research proposes a framework designed to resolve an optimal route planning problem by taking full account of additional moving cost such as road traffic cost and weather cost, among others. Recent technological development particularly in the ubiquitous computing environment has facilitated the collection of such data. This framework is based on the contexts of time, traffic, and environment, which addresses the following issues. First, we clarify and classify the diverse contexts that affect a vehicle's velocity and estimates the optimization of moving cost based on dynamic programming that accounts for the context cost according to the variance of contexts. Second, the velocity reduction rate is applied to find the optimal route (shortest path) using the context data on the current traffic condition. The velocity reduction rate infers to the degree of possible velocity including moving vehicles' considerable road and traffic contexts, indicating the statistical or experimental data. Knowledge generated in this papercan be referenced by several organizations which deal with road and traffic data. Third, in experimentation, we evaluate the effectiveness of the proposed context-based optimal route (shortest path) between locations by comparing it to the previously used distance-based shortest path. A vehicles' optimal route might change due to its diverse velocity caused by unexpected but potential dynamic situations depending on the road condition. This study includes such context variables as 'road congestion', 'work', 'accident', and 'weather' which can alter the traffic condition. The contexts can affect moving vehicle's velocity on the road. Since these context variables except for 'weather' are related to road conditions, relevant data were provided by the Korea Expressway Corporation. The 'weather'-related data were attained from the Korea Meteorological Administration. The aware contexts are classified contexts causing reduction of vehicles' velocity which determines the velocity reduction rate. To find the optimal route (shortest path), we introduced the velocity reduction rate in the context for calculating a vehicle's velocity reflecting composite contexts when one event synchronizes with another. We then proposed a context-based optimal route (shortest path) algorithm based on the dynamic programming. The algorithm is composed of three steps. In the first initialization step, departure and destination locations are given, and the path step is initialized as 0. In the second step, moving costs including composite contexts into account between locations on path are estimated using the velocity reduction rate by context as increasing path steps. In the third step, the optimal route (shortest path) is retrieved through back-tracking. In the provided research model, we designed a framework to account for context awareness, moving cost estimation (taking both composite and single contexts into account), and optimal route (shortest path) algorithm (based on dynamic programming). Through illustrative experimentation using the Wilcoxon signed rank test, we proved that context-based route planning is much more effective than distance-based route planning., In addition, we found that the optimal solution (shortest paths) through the distance-based route planning might not be optimized in real situation because road condition is very dynamic and unpredictable while affecting most vehicles' moving costs. For further study, while more information is needed for a more accurate estimation of moving vehicles' costs, this study still stands viable in the applications to reduce moving costs by effective route planning. For instance, it could be applied to deliverers' decision making to enhance their decision satisfaction when they meet unpredictable dynamic situations in moving vehicles on the road. Overall, we conclude that taking into account the contexts as a part of costs is a meaningful and sensible approach to in resolving the optimal route problem.

The Velocity Conversion Coefficient and Consistency for the Optimal Phase Ratio on the Performance of the Women's Triple Jump (여자 세단뛰기 운동수행의 일관성과 속도전환계수에 의한 최적의 국면비)

  • Ryu, Jae-Kyun;Chang, Jae-Kwan
    • Korean Journal of Applied Biomechanics
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    • v.25 no.1
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    • pp.39-47
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    • 2015
  • Objective : The purpose of this study was to investigate the velocity conversion coefficient and invariance for the optimal phase ratio on the performance of the women's triple jump. Methods : Three-dimensional kinematic data were obtained from the three finalists of the women's triple jumper competition at the 2011 Daegu IAAF World Championships. Computer simulations were performed using the biomechanical model of the triple jump to optimize the phase ratio for the longest actual distance for all athletes with altered velocity conversion coefficients. Results : Top elite triple jumpers showed better technical consistency at the phase ratio. Also, no consistent relationship was observed between the loss in horizontal velocity and the gain in vertical velocity across supporting the three phase. In addition, regardless of the magnitude A1, all athletes were optimized with jump-dominated technique. Finally, as the magnitude of A1 increased, the athletes showed better performance. The obtained overall distance jumped showed the longest actual distance when the optimal phase ratio was transferred from hop-dominated to jump-dominated(the step ratio was 30%~31%), and when the optimal phase ratio was transferred from balanced to jump-dominated(the step ratio was 27%~29%). Conclusion : Future studies need to be conducted in order to explore the active landing motion and the inclination angle of the body with the velocity conversion coefficient simultaneously at each supporting phase.

An Optimal Trajectory Planning for Redundant Robot Manipulators Based on Velocity Decomposition (속도분리를 이용한 여유자유도 로봇의 최적 경로계획)

  • 이지홍;원경태
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.7
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    • pp.836-840
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    • 1999
  • Linear motion and angular motion in task space are handled separately in joint velocity planning for redundant robot manipulators. In solving inverse kinematic equations with given joint velocity limits, we consider the order of priority for linear motion and angular motion. The proposed method will be useful in such applications where only linear motions are important than angular motions or vice versa.

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Time-optimal Trajectory Planning for a Robot System under Torque and Impulse Constraints

  • Cho, Bang-Hyun;Choi, Byoung-Suk;Lee, Jang-Myung
    • International Journal of Control, Automation, and Systems
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    • v.4 no.1
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    • pp.10-16
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    • 2006
  • In this paper, moving a fragile object from an initial point to a specific location in the minimum time without damage is studied. In order to achieve this goal, initially, the maximum acceleration and velocity ranges are specified. These ranges can be dynamically generate on the planned path by the manipulator. The path can be altered by considering the geometrical constraints. Later, considering the impulsive force constraint on the object, the range of maximum acceleration and velocity are obtained to preserve object safety while the manipulator is carrying it along the curved path. Finally, a time-optimal trajectory is planned within the maximum allowable range of acceleration and velocity. This time-optimal trajectory planning can be applied to real applications and is suitable for both continuous and discrete paths.