• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.370-372
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• 2008

본 연구에서는 이동 로봇에 영역 센서를 장착하여 실내에서 주변환경을 인식하여 지도를 작성하는 방법을 제안한다. 이동 로봇이 미지의 환경에서 자율 주행하기 위해서는 로봇 환경에 대한 지도를 작성하면서 이 지도 상에서 로봇의 위치를 인식할 수 있어야한다. 지도 작성과 위치 인식을 동시에 수행하는 SLAM을 구현하기위한 준비단계로서 본 논문에서는 일정한 시간 간격으로 연속적인 센서 신호들로 부터 동일 특징을 추출하고 이들을 서로 일치시켜서 로봇 이동 및 센서 신호에 불확실성이 있는 경우에도 지도를 작성하는 방법을 연구한다. 실제로 레이저 영역 센서를 장착한 이동 로봇을 이용하여 실내에서 지도를 작성하는 실험을 통하여 제안된 방법의 성능을 검증한다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.11a
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• pp.105-108
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• 1997

We developed a FLC(Fuzzy Logic Controller) for tracking control of MR(Mobile Robot) with obstacle avoidance. In this research, we made a heuristic approach to tracking control which is simple and efficient in almost every situation using FLC. In addition, smooth turn is accomplished and also obstacles are avoided. Also we used the XX(don't care) linguistic variable for inputs in FLC to make simple rule-table. With various simulations, the validity of our FLC was shown.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.415-418
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• 2002

MR의 자율주행 기능에는 추종, 접근, 충돌회피, 경고 등의 여러 기능이 있다. 이 기능들을하나의 Neural Network로 학습시키는 것은 어려운 일이다. 이것을 보안하고자 기능들을 각각의 Module로 구성하여 상황에 맞게 학습된 Module의 출력 값으로 MR을 제어하였다 로봇은 인간의 감각을 대신할 수 있는 다중 초음파 센서와 PC 카메라를 장착하고 있으며, 이곳에서 측정된 환경정보 데이터들은 Modular Neural Network을 통해 학습이 이루어진다 MNN에서의 출력값은 Gating Network(GN)에서 로봇의 진행 방향과 속도를 스위칭 출력함으로서 MR을 제어하는데 사용된다. MNN 내 EN의 활성화 함수 최적결합을 통해 효과적인 MNN을 구성하였다. 본 논문에서는 Modular Neural Network의 Expert Network(EN)을 최적설계 하였고, 제안한 MNN의 검증을 위해 실시간으로 MR에 구현하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.98-101
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• 2002

기존의 이동로봇 시스템은 완전한 자율주행이 주된 목표였으며 이때 영상정보는 단지 모니터링을 하는 보조적인 수단으로 사용되었다. 이에 따라 이동로봇의 자체 기능이 점차 고도화되는 방향으로 연구가 진행되었고, 제작비 또한 함께 상승하게 되었다. 그러나 구동만이 목적인 저렴한 이동로봇 시스템을 조작자가 원격 제어하는 것 또한 중요한 분야 중 하나이다. 이때 원격제어에 사용되는 신호로는 카메라에 의한 영상정보와 초음파 센서 등에 의한 거리정보를 주로 사용하게 된다. 그러나 영상정보는 3차원의 입체적 정보를 제공하는 데에는 부적절하기 때문에 초음파 센서를 이용한 거리정보가 매우 유용하게 된다. 본 논문에서는 초음파 센서의 정보를 이용한 원격제어용 힘 반향 조이스틱을 개발하였다. 힘 반향 알고리즘은 하나의 식으로 표현하기 곤란하므로 전문가 시스템의 구현이 매우 필요한 분야이다. 따라서 퍼지 논리를 사용하여 생성한 힘 반향 알고리즘을 이동로봇 원격제어에 사용함으로써 조작자가 이동로봇 주변환경을 쉽게 인식하여 이동로봇을 안전하게 주행할 수 있도록 하였다.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.92-97
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• 2024

This paper provides a study of distributional perspective on reinforcement learning for application in mobile robot navigation. Mapless navigation algorithms based on deep reinforcement learning are proven to promising performance and high applicability. The trial-and-error simulations in virtual environments are encouraged to implement autonomous navigation due to expensive real-life interactions. Nevertheless, applying the deep reinforcement learning model in real tasks is challenging due to dissimilar data collection between virtual simulation and the physical world, leading to high-risk manners and high collision rate. In this paper, we present distributional reinforcement learning architecture for mapless navigation of mobile robot that adapt the uncertainty of environmental change. The experimental results indicate the superior performance of distributional soft actor critic compared to conventional methods.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.03a
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• pp.127-130
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• 1998

In this paper, we propose a method of cooperative control(T-cell modeling) and selection of group behavior strategy(B-cell modeling) based on immune system in distributed autonomous robotic system(DARS). Immune system is living body's self-protection and self-maintenance system. Thus these features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For the purpose of applying immune system to DARS, a robot is regarded as a B cell, each environmental condition as an antigen, a behavior strategy as an antibody and control parameter as a T-call respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is stimulated and suppressed by other robot using communication. Finally much stimulated strategy is adopted as a swarm behavior strategy. This control scheme is based of clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy. By T-cell modeling, adaptation ability of robot is enhanced in dynamic environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.26-35
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• 2006

In this paper, an automatic mobile robot system for a intelligent path planning using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth information can be detected. Finally, based-on the analysis of these calculated coordinates, a mobile robot system is derived as a intelligent path planning and a estimation. From some experiments on robot driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the distance between the mobile robot and the objects, and relative distance between the other objects is found to be very low value of $2.19\%$ and $1.52\%$ on average, respectably.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2784-2786
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• 2000

Mobile robots include control modules for autonomous obstacle avoidance and navigation. They are range modules to detect and avoid obstacles. motor control modules to operate two wheels. and encoder modules for localization. There is needed an appropriate controller for each modules. In this paper. a control system. including 18 channels for Sonar sensors. 4 channels for PWM modules. and 4 channels for encoder modules. is proposed using TMS320C32 DSP adopted with CAN. The board communicates with other modules by CAN. so that mobile robots can perform several tasks in real time. So we can realize on autonomous mobile robot with basic functions such as obstacle avoidance by using the developed controller. Especially. this controller has 100 msec scan time for 16 sonar sensors and can detect closer objects comparing with standard sonar sensors.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.1
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• pp.111-118
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• 2004

In this paper, we present a novel approach for the structure of Fuzzy Neural Network(FNN) based on wavelet function and apply this network structure to the solution of the tracking problem for mobile robots. Generally, the wavelet fuzzy model(WFM) has the advantage of the wavelet transform by constituting the fuzzy basis function(FBF) and the conclusion part to equalize the linear combination of FBF with the linear combination of wavelet functions. However, it is very difficult to identify the fuzzy rules and to tune the membership functions of the fuzzy reasoning mechanism. Neural networks, on the other hand, utilize their learning capability for automatic identification and tuning. Therefore, we design a wavelet based FNN structure(WFNN) that merges these advantages of neural network, fuzzy model and wavelet transform. The basic idea of our wavelet based FNN is to realize the process of fuzzy reasoning of wavelet fuzzy system by the structure of a neural network and to make the parameters of fuzzy reasoning be expressed by the connection weights of a neural network. And our network can automatically identify the fuzzy rules by modifying the connection weights of the networks via the gradient descent scheme. To verify the efficiency of our network structure, we evaluate the tracking performance for mobile robot and compare it with those of the FNN and the WFM.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.737-742
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application area, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggest based on experimental results obtain from computer simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.