• Title, Summary, Keyword: Formation control

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Spacecraft Formation Reconfiguration using Impulsive Control Input

  • Bae, Jonghee;Kim, Youdan
    • International Journal of Aeronautical and Space Sciences
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    • v.14 no.2
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    • pp.183-192
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    • 2013
  • This paper presents formation reconfiguration using impulsive control input for spacecraft formation flying. Spacecraft in a formation should change the formation size and/or geometry according to the mission requirements and space environment. To modify the formation radius and geometry with respect to the leader spacecraft, the follower spacecraft generates additional control inputs; the two impulsive control inputs are general control type of the spacecraft system. For the impulsive control input, Lambert's problem is modified to construct the transfer orbit in relative motion, given two position vectors at the initial and final time. Moreover, the numerical simulation results show the transfer trajectories to resize the formation radius in the radial/along-track plane formation and in the along-track/cross-track plane formation. In addition, the maneuver characteristics are described by comparing the differential orbital elements between the reference orbit and transfer orbit in the radial/along-track plane formation and along-track/cross-track plane formation.

Leader-Following Formation Control of Multiple Robots with Uncertainties through Sliding Mode and Nonlinear Disturbance Observer

  • Qian, Dianwei;Tong, Shiwen;Li, Chengdong
    • ETRI Journal
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    • v.38 no.5
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    • pp.1008-1018
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    • 2016
  • This paper presents a control scheme for the leader-following formation of multiple robots. The control scheme combines the sliding mode control (SMC) method with the nonlinear disturbance observer (NDOB) technique. The formation dynamics suffer from uncertainties because the individual robots are uncertain. Concerning such formation uncertainties, the leader-following formation dynamics are modeled. Assuming that the formation uncertainties have an unknown boundary, an NDOB-based observer was designed to estimate the formation uncertainties. A sliding surface containing the observer outputs has been defined. Regarding the sliding surface, an SMC-based controller was investigated to form uncertain robots. A sufficient condition in the sense of the Lyapunov theory was proven such that the formation system is asymptotically stable. Herein, some comparison results between the sole SMC method and the second-order SMC method are presented to demonstrate the effectiveness and feasibility of the control scheme for multiple robots in the presence of uncertainties.

Nanosat Formation Flying Design for SNIPE Mission

  • Kang, Seokju;Song, Youngbum;Park, Sang-Young
    • Journal of Astronomy and Space Sciences
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    • v.37 no.1
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    • pp.51-60
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    • 2020
  • This study designs and analyzes satellite formation flying concepts for the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE) mission, that will observe the near-Earth space environment using four nanosats. To meet the requirements to achieve the scientific objectives of the SNIPE mission, three formation flying concepts are analyzed: a cross-shape formation, a square-shape formation, and a cross-track formation. Of the three formation flying scenarios, the cross-track formation scenario is selected as the final scenario for the SNIPE mission. The result of this study suggests a relative orbit control scenario for formation maintenance and reconfiguration, and the initial relative orbits of the four nanosats meeting the formation requirements and thrust limitations of the SNIPE mission. The formation flying scenario is validated by calculating the accumulated total thrust required for the four nanosats. If the cross-track formation scenario presented in this study is applied to the SNIPE mission, it is expected that the mission will be successfully accomplished.

Nash equilibrium-based geometric pattern formation control for nonholonomic mobile robots

  • Lee, Seung-Mok;Kim, Hanguen;Lee, Serin;Myung, Hyun
    • Advances in robotics research
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    • v.1 no.1
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    • pp.41-59
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    • 2014
  • This paper deals with the problem of steering a group of mobile robots along a reference path while maintaining a desired geometric formation. To solve this problem, the overall formation is decomposed into numerous geometric patterns composed of pairs of robots, and the state of the geometric patterns is defined. A control algorithm for the problem is proposed based on the Nash equilibrium strategies incorporating receding horizon control (RHC), also known as model predictive control (MPC). Each robot calculates a control input over a finite prediction horizon and transmits this control input to its neighbor. Considering the motion of the other robots in the prediction horizon, each robot calculates the optimal control strategy to achieve its goals: tracking a reference path and maintaining a desired formation. The performance of the proposed algorithm is validated using numerical simulations.

Cooperative Particle Swarm Optimization-based Model Predictive Control for Multi-Robot Formation (군집 로봇 편대 제어를 위한 협력 입자 군집 최적화 알고리즘 기반 모델 예측 제어 기법)

  • Lee, Seung-Mok;Kim, Hanguen;Myung, Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.5
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    • pp.429-434
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    • 2013
  • This paper proposes a CPSO (Cooperative Particle Swarm Optimization)-based MPC (Model Predictive Control) scheme to deal with formation control problem of multiple nonholonomic mobile robots. In a distributed MPC framework, each robot needs to optimize control input sequence over a finite prediction horizon considering control inputs of the other robots where their cost functions are coupled by the state variables of the neighboring robots. In order to optimize the control input sequence, a CPSO algorithm is adopted and modified to fit into the formation control problem. Experiments are performed on a group of nonholonomic mobile robots to demonstrate the effectiveness of the proposed CPSO-based MPC for multi-robot formation.

Formation of Mobile Robots with Inaccurate Sensor Information

  • Kim, Gunhee;Lee, Doo-Yong;Lee, Kyungno
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.4
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    • pp.203-209
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    • 2001
  • This paper develops a control method for some generic formation tasks of multiple mobile robots with inaccurate sensor information. Inaccurate sensor information means that all the robots have only local sensors that cannot accurately measure absolute distances and directions of objects. That is, all the sensors have limitation on the range, and uncertainty in the values. Therefore, more robust and reliable control logic is proposed and implemented. The logic is developed considering generic situations and increasing the number of robots participating in the formation. Petri nets are used for modeling and design of the control logic, which can visualize the control models and make it easy to check the states of each robot. Physically homogeneous mobile robots are designed and built to evaluate the developed logic. Each robot is equipped with eighteen infrared sensors and a UHF transceiver module. The experiment results are analyzed quantitatively by using the data of the relative distances and angles between the robots. And the trajectories of the robots during the formation are also evaluated. The developed control approach is demonstrated with experiments to be successful and efficient for the formation of autonomous mobile robots.

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Formation Flight Control of Unmanned Aerial Vehicles Using Model Predictive Control (모델 예측 기법 기반 무인 항공기의 편대 비행 제어 알고리즘)

  • Park, Jae-Mann;Shin, Jong-Ho;Kim, Hyoun-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.14 no.12
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    • pp.1212-1217
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    • 2008
  • This paper studies the feasibility of using the nonlinear model predictive control as a formation flight control algorithm for unmanned aerial vehicles. The optimal control inputs for formation flight are calculated through the cost function which incorporates the relative positions of the individual vehicles to maintain a desired formation and also the inequality constraints on inputs and states using the Karush-Kuhn-Tucker conditions. In the nonlinear model predictive control setting, the optimal control inputs are implemented in a receding horizon manner, which is suitable for dealing with dynamic constraints. Numerical simulations are executed for the validation of the proposed scheme.

Formation Motion Control for Swarm Robots (군집 로봇의 포메이션 이동 제어)

  • La, Byoung-Ho;Kim, Sung-Ho;Joo, Young-Hoon
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.11
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    • pp.2147-2151
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    • 2011
  • In this paper, we propose the formation control algorithm for swarm robots. The proposed algorithm uses the artificial potential field(APF) to plan the global path of swarm robots and to control the formation movement. The navigation function generates a global APF for a leader robot to reach a given destination and an avoidance function generates a local APF for follow robots to avoid obstacles. Finally, some simulations show the validity of the proposed method.

An Implementation of Formation Flight Control System Using Two Drones (두 대의 드론을 이용한 편대 비행 제어 시스템 구현)

  • Kim, Dong-Jin;Park, Young-Seak
    • IEMEK Journal of Embedded Systems and Applications
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    • v.11 no.6
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    • pp.343-351
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    • 2016
  • In this study, we implemented a formation flight control system using two drones. Ground control system communicates with drones by MAVLink protocol, does keep watch on drone's status and sends simultaneously formation flight instructions to drones in real time. Two drones have been able to fly by a formation flight algorithm without crashing while maintaining the same speed, and a constant distance and altitude.

Formation Control of Mobile Robot for Moving Object Tracking (이동물체 추적을 위한 이동로봇의 대형제어)

  • Oh, Young-Suk;Lee, Chung-Ho;Park, Jong-Hun;Kim, Jin-Hwan;Huh, Uk-Youl
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.4
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    • pp.856-861
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    • 2011
  • The mobile robot controller is designed to track the target and to maintain the formation at the same time. Formation control is included in mobile robot controller by extending the trajectory tracking algorithm. The dynamic model of mobile robot is used with kinematic model considering the practical physical parameters of mobile robot. The dynamic model of mobile robot transforms velocity control input of kinematic model into torque control input which is the practical control input of mobile robot. Formation controller of mobile robot is designed to satisfy Lyapunov stability by backstepping method. The designed formation controller is applied to the mobile robot for various target movements and simulated to confirm the Lyapunov stability.