TWR 기반 군집 협업측위 시스템의 오차 전파 분석

임정민,이창은,성태경,Lim, Jeong-Min,Lee, Chang-Eun,Sung, Tae-Kyung 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.9

Alternative radio-navigation technologies aim at providing continuous navigation solution even if one cannot use GNSS (Global Navigation Satellite System). In shadowing region such as indoor environment, GNSS signal is no longer available and the alternative navigation system should be used together with GNSS to provide seamless positioning. For soldiers in battlefield where GNSS signal is jammed or in street battle, the alternative navigation system should work without positioning infrastructure. Moreover, the radio-navigation system should have scalability as well as high accuracy performance. This paper presents a TWR (Two-Way-Ranging)-based cooperative positioning system (CPS) that does not require location infrastructure. It is assumed that some members of CPS can obtain GNSS-based position and they are called mobile anchors. Other members unable to receive GNSS signal compute their position using TWR measurements with mobile anchors and neighboring members. Error propagation in CPS is analytically studied in this paper. Error budget for TWR measurements is modeled first. Next, location error propagation in CPS is derived in terms of range errors. To represent the location error propagation in the CPS, Location Error Propagation Indicator (LEPI) is proposed in this paper. Simulation results show that location error of tags in CPS is mainly influenced by the number of hops from anchors to the tag to be positioned as well as the network geometry of CPS.

TWR 기반 군집 협업측위 시스템의 오차 전파 분석

임정민(Jeong-Min Lim),이창은(Chang-Eun Lee),성태경(Tae-Kyung Sung) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.4

Alternative radio-navigation technologies aim at providing continuous navigation solution even if one cannot use GNSS (Global Navigation Satellite System). In shadowing region such as indoor environment, GNSS signal is no longer available and the alternative navigation system should be used together with GNSS to provide seamless positioning. For soldiers in battlefield where GNSS signal is jammed or in street battle, the alternative navigation system should work without positioning infrastructure. Moreover, the radio-navigation system should have scalability as well as high accuracy performance. This paper presents a TWR (Two-Way-Ranging)-based cooperative positioning system (CPS) that does not require location infrastructure. It is assumed that some members of CPS can obtain GNSS-based position and they are called mobile anchors. Other members unable to receive GNSS signal compute their position using TWR measurements with mobile anchors and neighboring members. Error propagation in CPS is analytically studied in this paper. Error budget for TWR measurements is modeled first. Next, location error propagation in CPS is derived in terms of range errors. To represent the location error propagation in the CPS, Location Error Propagation Indicator (LEPI) is proposed in this paper. Simulation results show that location error of tags in CPS is mainly influenced by the number of hops from anchors to the tag to be positioned as well as the network geometry of CPS.

재난 구조용 다중 로봇을 위한 GNSS 음영지역에서의 TWR 기반 협업 측위 기술

이창은,성태경 한국로봇학회 2016 로봇학회 논문지 Vol.11 No.3

For a practical mobile robot team such as carrying out a search and rescue mission in a disaster area, the localization have to be guaranteed even in an environment where the network infrastructure is destroyed or a global positioning system (GPS) is unavailable. The proposed architecture supports localizing robots seamlessly by finding their relative locations while moving from a global outdoor environment to a local indoor position. The proposed schemes use a cooperative positioning system (CPS) based on the two-way ranging (TWR) technique. In the proposed TWR-based CPS, each non-localized mobile robot act as tag, and finds its position using bilateral range measurements of all localized mobile robots. The localized mobile robots act as anchors, and support the localization of mobile robots in the GPS-shadow region such as an indoor environment. As a tag localizes its position with anchors, the position error of the anchor propagates to the tag, and the position error of the tag accumulates the position errors of the anchor. To minimize the effect of error propagation, this paper suggests the new scheme of full-mesh based CPS for improving the position accuracy. The proposed schemes assuring localization were validated through experiment results.

제어방식에 따른 다축 고정도 위치동기제어계의 성능비교

최봉석(B. S. Choi),정석권(S. K. Jeong),유삼상(S. S. You) 한국동력기계공학회 2004 한국동력기계공학회 학술대회 논문집 Vol.- No.-

This paper describes a comparison of control performance in multi-axes precise position synchronous system according to control methods. The control method is mainly divided as two manners such as master-slave and cooperative control in the multi-axes system. Also, each axis is divided as two types, current control type and acceleration control type, according to a kind of inner loop. Maximum error comparison as a coupling method is used to minimize position synchronous errors. The control performances of position synchronous control are investigated through numerical simulations under various control methods.

Seamless Routing and Cooperative Localization of Multiple Mobile Robots for Search and Rescue Application

이창은,임현자,임정민,조영조,성태경 한국전자통신연구원 2015 ETRI Journal Vol.37 No.2

In particular, for a practical mobile robot team to perform such a task as that of carrying out a search and rescue mission in a disaster area, the network connectivity and localization have to be guaranteed even in an environment where the network infrastructure is destroyed or a Global Positioning System is unavailable. This paper proposes the new collective intelligence network management architecture of multiple mobile robots supporting seamless network connectivity and cooperative localization. The proposed architecture includes a resource manager that makes the robots move around and not disconnect from the network link by considering the strength of the network signal and link quality. The location manager in the architecture supports localizing robots seamlessly by finding the relative locations of the robots as they move from a global outdoor environment to a local indoor position. The proposed schemes assuring network connectivity and localization were validated through numerical simulations and applied to a search and rescue robot team.

Cooperative Control of Multiple Dynamic Positioning Vessels with Input Saturation Based on Finite-time Disturbance Observer

Guoqing Xia,Chuang Sun,Bo Zhao,Jingjing Xue 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.2

This paper presents a new cooperative control strategy for dynamic positioning of multiple surface vesselssubject to unknown time-varying environmental disturbances and input saturation. The vessels are assumedinterconnected through a directed topology rather than bidirectional. Two control objectives are considered in thispaper. The first one is to make these vessels track desired positions and headings, and the other control objective isto hold the desired formation. For these purposes, we propose a cooperative control which consists of finite-timedisturbance observer, auxiliary dynamic system and dynamic surface control technique. A nonlinear finite-timeobserver is developed to estimate unknown time-varying disturbance. To tackle the input saturation problem, anauxiliary dynamic system is constructed. It is also proved that all signals in the closed-loop control system convergeto a small neighborhood of equilibrium state via Lyapunov analysis. Simulation results are given to validate theeffectiveness of the proposed control strategy.

STABILITY OF POSITIVE STEADY-STATE SOLUTIONS IN A DELAYED LOTKA-VOLTERRA DIFFUSION SYSTEM

Yan, Xiang-Ping,Zhang, Cun-Hua Korean Mathematical Society 2012 대한수학회지 Vol.49 No.4

This paper considers the stability of positive steady-state solutions bifurcating from the trivial solution in a delayed Lotka-Volterra two-species predator-prey diffusion system with a discrete delay and subject to the homogeneous Dirichlet boundary conditions on a general bounded open spatial domain with smooth boundary. The existence, uniqueness and asymptotic expressions of small positive steady-sate solutions bifurcating from the trivial solution are given by using the implicit function theorem. By regarding the time delay as the bifurcation parameter and analyzing in detail the eigenvalue problems of system at the positive steady-state solutions, the asymptotic stability of bifurcating steady-state solutions is studied. It is demonstrated that the bifurcating steady-state solutions are asymptotically stable when the delay is less than a certain critical value and is unstable when the delay is greater than this critical value and the system under consideration can undergo a Hopf bifurcation at the bifurcating steady-state solutions when the delay crosses through a sequence of critical values.

Stability of positive steady-state solutions in a delayed Lotka-Volterra diffusion system

Xiang-Ping Yan,Cun-Hua Zhang 대한수학회 2012 대한수학회지 Vol.49 No.4

This paper considers the stability of positive steady-state so-lutions bifurcating from the trivial solution in a delayed Lotka-Volterra two-species predator-prey diffusion system with a discrete delay and sub-ject to the homogeneous Dirichlet boundary conditions on a general boun-ded open spatial domain with smooth boundary. The existence, unique-ness and asymptotic expressions of small positive steady-sate solutions bifurcating from the trivial solution are given by using the implicit func-tion theorem. By regarding the time delay as the bifurcation parameter and analyzing in detail the eigenvalue problems of system at the positive steady-state solutions, the asymptotic stability of bifurcating steady-state solutions is studied. It is demonstrated that the bifurcating steady-state solutions are asymptotically stable when the delay is less than a certain critical value and is unstable when the delay is greater than this critical value and the system under consideration can undergo a Hopf bifurcation at the bifurcating steady-state solutions when the delay crosses through a sequence of critical values.

모바일 센서 네트워크에서 효율적인 노드 위치 결정

박나연,손철수,김원중,Park, Na-Yeon,Son, Cheol-Su,Kim, Won-Jung 한국전자통신학회 2010 한국전자통신학회 논문지 Vol.5 No.4

모바일 센서 네트워크는 기존의 위치가 고정된 무선 센서 네트워크와는 다르게 비컨 노드와 일반 노드가 모두 움직일 수 있기 때문에 위치 측정 알고리즘이 일반적인 무선 센서 네트워크 환경의 알고리즘 보다 어렵다. 특히 모바일 센서 네트워크에서 노드의 움직임이 빠를 경우 기존의 위치 측정 알고리즘으로는 원하는 시간 내에 위치를 측정할 수 없다. 본 연구에서는 이러한 모바일 센서 네트워크에서의 위치 측정 알고리즘을 제안하고 성능을 향상시켜 실시간에 위치를 측정할 수 있는 기법을 연구하였다. Because mobile sensor network is different with the existing wireless sensor network with fixed nodes, it is more difficult to implement a positioning algorithm in mobile sensor network than in mobile sensor network. In case of fast moving node, a positioning algorithm may be not completed in a given time. In this paper we present the positioning algorithm that improves performance and can complete a computation in time on mobile sensor network.

2019년 한국 보건의료의 상대적 위치와 추이: 경제협력개발기구 국가와 비교

박민아,윤흰뫼,박은철 한국보건행정학회 2022 보건행정학회지 Vol.32 No.1

This study aims to compare the healthcare status of South Korea and other member of the Organization for Economic Cooperationand Development (OECD) using the OECD health statistics 2021. We used the position value for relative comparison (PARC) index tomeasure the five elements of the healthcare system, demand, supply, accessibility, quality, and cost. For the statistical analysis,Mann-Kendall test was performed to examine the trend of the PARC values from 2000 to the most recent year. The results showedthat supply, demand, accessibility, and quality were above median than the OECD median and the cost was below median. In sectorssuch as primary care, health employment and mental health care were below median average. With these result, necessary steps fora sustainable healthcare should be taken into effort by policy makers.