• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.330-333
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• 2005

In this study, a method of designing a neurointerface using neural network (NN) is proposed for controlling nonholonomic mobile robots. According to the concept of virtual master-slave robots, in particular, a partially stable inverse dynamic model of the master robot is acquired online through the NN by applying a feedback-error learning method, in which the feedback controller is assumed to be based on a PD compensator for such a nonholonomic robot. A tracking control problem is demonstrated by some simulations for a nonholonomic mobile robot with two-independent driving wheels.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.818-829
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• 2003

A cooperating control algorithm for two nonholonomic mobile robots is proposed. The task is composed of collision avoidance against obstacles and carrying a ladder. The front robot and the rear robot are called the leader and the follower, respectively. Each robot has a nonholonomic constraint so it cannot move in perpendicular directions. The environment is initially supposed to be unknown except target position. The torque that drives leader is determined by distance between the leader and the target position or the distance between it and the obstacles. The torque by target is attractive and the torque by obstacles is repulsive. The two mobile robots are supposed to be connected by link that can be expanded and contracted. The follower computes its torque using position and orientation information from the leader by communication. Simulation results show that the robots can drive to target position without colliding into the obstacles and maintain the distance in the allowable range.

• 한국생산제조학회지
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• 제24권1호
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• pp.98-102
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• 2015

This paper proposes an autonomous navigation method for a nonholonomic mobile robot, based on the generalized Voronoi diagram (GVD). We define the look-ahead point for a given motion constraint to determine the direction of motion, which solves the problem of a minimum turning radius for the real nonholonomic mobile robot. This method can be used to direct the robot to explore an unknown environment and construct smooth feedback curves for the nonholonomic robot. As the trajectories can be smoothed, the position of the robot can be stabilized in the plane. The simulation results are presented to verify the performance of the proposed methods for the nonholonomic mobile robot. Furthermore, this approach is worth drawing on the experience of any other mobile robots.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권12호
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• pp.583-595
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• 2002

Homing operation can be defined as a series of actions which are necessary for a mobile robot to move from the current position with any arbitrary orientation to a desired position with a specified orientation, while avoiding possible obstacles. In this paper, a homing and obstacle avoidance algorithm for nonholonomic mobile robots is proposed. The proposed algorithm consists of a local goal generator, a discrete state controller, and local path tracking controller based on Aicardi's path following algorithm. In the discrete state controller, 4 states are defined according to the environmental conditions and 4 desired high-level command for the states are given as follows: avoid, wander, home and homing zones. The proposed local goal generator is designed to generate the desired local path by using weighted distance transforms which are newly made to satisfy the nonholonomic constraints of mobile robots. Here, subgoals are also found as vertices of the desired local path. To demonstrate result effectiveness and applicability of the proposed algorithm, computer simulations are illustrated and experimental results for a real mobile robot system are also provided.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.449-452
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• 1996

In this paper, a robust.adaptive control scheme is presented for precise trajectory tracking of nonholonomic mobile robots. In the controller, a set of desired trajectory is defined and used in constructing the control input which constitutes the main part of the proposed controller. The stable operating characteristics such as precise trajectory tracking, parameter estimation, disturbance suppression, tec., are shown through experiments as well as computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1172-1177
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• 2003

In this paper, we propose an obstacle avoidance technique in trajectory tracking of nonholonomic wheeled mobile robots. Input-output linearized backstepping controller is used in trajectory tracking, and repulsive type control input for obstacle avoidance is added to it. The added input is generated by fuzzy logic. And we do not add the two inputs directly but combine them via fuzzy logic, which determines the ratings of each input. Some simulations are performed to show that with the proposed algorithm, the mobile robot can track its reference trajectory even if there are multiple obstacles on the trajectory of robot.

• Transactions on Control, Automation and Systems Engineering
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• 제2권3호
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• pp.201-206
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• 2000

In this paper, a posture control for nonholonomic mobile robots is proposed with an empirical basis. In order to obtain fast and consecutive motions in realistic applications, the motion requirements of a mobile robot are defined. Under the assumption of a velocity controller designed with the selection guidance of control parameters, the algorithm of posture control is presented and experimentally demonstrated for practicality and effectiveness.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1829-1830
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• 2008

The paper deals with leader-follower formations of nonholonomic mobile robots using least square method in order to maintain the formation constantly. The nonholonomic property of the mobile robot cause us to use the least square method. Then, the performance of the developed formation controller is verified by simulation results.

• 한국지능시스템학회논문지
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• 제21권5호
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• pp.602-608
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• 2011

본 논문에서는, 신경망을 이용한 뉴로 인터페이스 설계를 통해 논홀로노믹 이동 로봇을 제어하는 방법을 제시하였다. 특히, 가상의 마스터-슬레이브 로봇 개념을 이용하여, 부분적으로 안정된 마스터 로봇의 역 동적모델이 피드백-에러 학습법을 적용한 신경망을 통해 온라인으로 획득되도록 하였다. 이 피드백 제어기는 PD 보상기에 기초를 두고 있다. 온라인 학습을 위한 신경망은 입력층이 6개의 입력세포들($x_i$, i=1~6)로 구성되어있으며, 1개의 은닉층에는 2개의 은닉세포($o_j$, j=1~2), 출력층은 2개의 출력세포(${\tau}_k$, k=1~2)로 구성되었고, 신경망의 온라인 학습을 위하여 최소자승법에 의한 오류역전파 알고리즘을 이용하였다. 본 연구에서 개발된 뉴로 인터페이스의 경로추적제어에 관한 성능은 2-wheel 독립구동이 가능한 논홀로노믹 이동 로봇의 시뮬레이션으로 증명하였다.

• Advances in robotics research
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• 제1권1호
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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.