• Journal of the Korean Society of Industry Convergence
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• v.18 no.1
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• pp.30-36
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• 2015

This paper presents the theoretical development of a complete navigation problem of a nonholonomic mobile robot by using ultrasonic sensors. To solve this problem, a new method to computer a fuzzy perception of the environment is presented, dealing with the uncertainties and imprecision from the sensory system and taking into account nonholonomic constranits of the robot. Fuzzy perception, fuzzy controller are applied, both in the design of each reactive behavior and solving the problem of behavior combination, to implement a fuzzy behavior-based control architecture. The performance of the proposed obstacle avoidance robot controller in order to determine the exact dynamic system modeling system that uncertainty is difficult for nomadic controlled robot direction angle by ultrasonic sensors throughout controlled performance tests. In additionally, this study is an in different ways than the self-driving simulator in the development of ultrasonci sensors and unmanned remote control techniques used by the self-driving robot controlled driving through an unmanned remote controlled unmanned realize the performance of factory antomation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.92-98
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• 2014

This paper proposes a hermite spline based D* algorithm for effective path planning of mobile robot to improve the detecting speed. In conventional path planning research, a robot is supposed to pass through predetermined centers of grid partitions of area. However it doesn't guarantee the optimal path during its navigation. In addition, a robot is hard to avoid obstacles effectively. The proposed algorithm in this paper makes use of stochastic characteristics of nonholonomic mobile robot and estimation of shortest path to curvature movement of the robot. The performance evaluation of the improved spline D* algorithm performed through simulation shows its effectiveness. Moreover, the experiment verifies that a robot can find the shortest path by building the curve paths while it is moving on the path in spline.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.127-132
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• 1998

Mobile wheeled robots are nonholonomically constrained systems. Generally, it is very difficult to describe the motion of mechanical systems with nonintegrable nonholonomic constraints. An objective of this study is to describe the motion of a robot with a free wheel. The motion of holonomically and/or nonholonomically constrained system can be simply determined by Generalized Inverse Method presented by Udwadia and Kalaba in 1992. Using the method, we describe the exact motion of the robot and determine the constraint force exerted on the robot for satisfying constraints imposed on it. The application illustrates the ease with which the Generalized Inverse Method can be utilized for the purpose of control of nonlinear system without depending on any linearization, maintaining precision tracking motion and explicit determination of control forces of nonholonomically constrained system.

• The Journal of Korea Robotics Society
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• v.4 no.4
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• pp.273-280
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• 2009

It is difficult to find a practical solution for the backward-motion control of a car-like mobile robot with n passive trailers. Unlike an omni-directional robot, a car-like mobile robot has nonholonomic constraints and limitations of the steering angle. For these reasons, the backward motion control problem of a car-like mobile robot with $n$ passive trailers is not trivial. In spite of difficulties, backing up a trailer system is useful for parking control. In this study, we proposed a mechanical alteration which is connecting $n$ passive trailers to the front bumper of a car to improve the backward motion control performance. Theoretical verification and simulations show that the backward-motion control of a general car with n passive trailers can be successfully carried out by using the proposed approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.1305-1308
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• 2015

모바일 로봇의 경로 계획의 경우 주로 위치로 표현되는 2차원 공간 상에서 현재 위치에서 목표 위치까지 모바일 로봇이 도달하도록 경로를 계획한다. 그러나 nonholonomic 구조를 가지는 모바일 로봇의 경우 기구학적 제약에 의해 추종 불가능한 경로가 존재하게 된다. 또한 nonholonomic 모바일 로봇은 진행 방향을 포함한 3차원 공간 상에서의 경로 계획이 이루어져야 한다. 모바일 로봇의 경로 계획 알고리즘으로는 A* 경로 계획 알고리즘이 주로 사용되는데, A* 경로 계획 알고리즘은 경로 계획 시 현재 위치에서부터 노드를 확장시켜 가며 경로를 탐색한다. 이 때 각 노드로부터 목표 위치까지의 비용을 계산하기 위해 heuristic 함수가 사용된다. 기존의 A* 경로 계획 알고리즘의 경우 Euclidean 거리에 기반한 heuristic 함수가 사용되었으나, 이 경우 모바일 로봇의 진행 방향은 고려하지 않아, 로봇의 목표 위치에 도말만 할 뿐 목표 방향으로의 도달은 보장 할 수 없다. 본 논문에서는, A* 경로 계획 알고리즘을 통해 nonholonomic 모바일 로봇이 목표 위치에 목표 방향에 맞추어 도달할 수 있도록 경로 생성이 이루어지는 heuristic 함수를 제안하고, 시뮬레이션을 통해 그 성능을 검증한다.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.530-533
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• 1995

This paper deals with the problem of motion planning for a unicycle-like robot. We present a simple local planner for unicycle model, based on an approximation of the desired configuration generated by local holonomic planner that ignores motion constraints. To guarantee a collision avoidance, we propose an inequality constraint, based on the motion analysis with the constant control input and time interval. Consequently, we formulate our problem as the constrained optimization problem and a feedback scheme based on local sensor information is established by simply solving this problem. Through simulations, we confirm the validity and effectiveness of our algorithm.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.664-674
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• 2009

This paper presents the theoretical development of a complete navigation problem of a non-holonomic mobile robot by using sonar sensors. To solve this problem, a new method to compute a fuzzy perception of the environment is presented, dealing with the uncertainties and imprecision from the sensory system and taking into account nonholonomic constraints of the robot. Fuzzy perception, fuzzy controller are applied, both in the design of each reactive behavior and solving the problem of behavior combination, to implement a fuzzy behavior-based control architecture. Different experiments in populated environments have proved to be very successful. Our method is able to guide the mobile robot named KUM-Robo safety and efficiently during long experimental time.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.301-306
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• 2021

In this paper, we propose a modified back-stepping control method in view of the dynamic model of mobile manipulator has the nonholonomic constraints, these constraints should be considered to design a tracking controller for the mobile manipulator. The conventional back-stepping controller includes the dynamics and kinematics of the mobile robot systems. and the modified adaptive back0stepping method is applied to constructing the controller. The proposed controller can realize the tracking trajectory of the reference path. The efficiency and robustness of this control method is demonstrated by the simulation.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.23-26
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• 2000

Generally, the wheel-driven mobile robot systems, by their structural property, have nonholonomic constraints. These constraints are not integrable and cannot be written as time derivatives of some functions with respect to the generalized coordinates. Hence, nonlinear approaches are required to solve the problems. In this paper, the trajectory controller of wheeled mobile robot systems is suggested to guarantee its convergence to reference trajectory. Design procedure of the suggested trajectory controller is back-stepping scheme which was introduced recently in nonlinear control theory. The performance of the proposed trajectory controller is verified via computer simulation. In the simulation, the trajectory controller is applied to differentially driven robot system and car-like mobile robot system on the assumption that the trajectory planner be given.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.5
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• pp.121-127
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• 2019

This paper proposes an operator-centric velocity generation and control algorithm for differential-drive mobile robots, which are widely used in many industrial applications. Most of the previous works use a robot centric velocity generation and control for the operators to control the differential-drive mobile robots, which makes the robot control difficult for the operators. Such robot-centric control can cause the increase of accidents and the decrease of work efficiency. The experimental results with a real differential-drive mobile robot testbed demonstrate the efficiency of operator-centric mobile robot control.