• ETRI Journal
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• 제38권6호
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• pp.1229-1239
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• 2016

For efficient interaction between humans and robots, robots should be able to understand the meaning and intention of human behaviors as well as recognize them. This paper proposes an interactive human intention reading method in which a robot develops its own knowledge about the human intention for an object. A robot needs to understand different human behavior structures for different objects. To this end, this paper proposes a hierarchical behavior knowledge network that consists of behavior nodes and directional edges between them. In addition, a human intention reading algorithm that incorporates reinforcement learning is proposed to interactively learn the hierarchical behavior knowledge networks based on context information and human feedback through human behaviors. The effectiveness of the proposed method is demonstrated through play-based experiments between a human and a virtual teddy bear robot with two virtual objects. Experiments with multiple participants are also conducted.

• 정보교육학회논문지
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• 제12권2호
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• pp.195-202
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• 2008

로봇을 이용한 프로그래밍 학습은 획일적이고 정형화된 기존 교육환경에서 벗어나 미래사회의 창의적 학습을 미리 경험할 수 있으며 수학 및 과학의 가장 기초가 되는 알고리즘을 이해하고 향상시키는데 가장 적절한 학습방법이다. 본 연구에서는 초등학생들이 로봇프로그래밍 시 나타날 수 있는 오류의 유형들을 제안하였으며 학습을 위한 교육과정을 개발한 후 초등학생 5, 6학생들을 대상으로 로봇프로그래밍 학습을 시켰다. 학습과정에서 발생한 오류들을 수집하고 분류하였으며 또한, 기존 연구된 컴퓨터기반 프로그래밍언어와 비교 분석하였다. 본 연구에서의 로봇프로그래밍 실행경험을 통해 컴퓨터기반 프로그래밍에서 창의성학습에 큰 장애요소로 평가된 오류요소들 즉, 프로그램사용 미숙으로 인한 오류, 단순한 오타, 문법오류 그리고 코딩실수 등을 전체 오류의 약 21%로 나타나 기존 컴퓨터기반 프로그래밍언어 학습에서 조사된 오류비율(약 53%)에 비해 현저하게 줄어드는 것으로 분석되었다. 이러한 오류의 감소는 초등학생들의 흥미도와 성취도 향상을 위한 주요요소로 판단된다. 따라서, 학습과정에서 보다 많은 논리 및 문제해결을 위한 요소들에 노출되어 있어 창의성 알고리즘 학습에 매우 효과적임을 알 수 있다.

• 로봇학회논문지
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• 제18권2호
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• pp.225-232
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• 2023

With the recent increase of multiple robots cooperating in smart manufacturing logistics environments, it has become very important how to predict the safety and efficiency of the individual tasks and dynamically assign them to the best one of available robots. In this paper, we propose a novel task policy learner based on deep relational reinforcement learning for predicting the safety and efficiency of tasks in a multi-robot manufacturing logistics environment. To reduce learning complexity, the proposed system divides the entire safety/efficiency prediction process into two distinct steps: the policy parameter estimation and the rule-based policy inference. It also makes full use of domain-specific knowledge for policy rule learning. Through experiments conducted with virtual dynamic manufacturing logistics environments using NVIDIA's Isaac simulator, we show the effectiveness and superiority of the proposed system.

• 공학교육연구
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• 제15권4호
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• pp.85-93
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• 2012

본 연구는 로봇활용수업이 초등학생의 학습태도에 미치는 효과를 밝히려는 것이다. 연구 결과, 로봇활용수업을 실시한 후의 학습태도 점수는 실시 전에 비해 뚜렷한 향상을 보여, 수업에서 로봇을 활용하는 경우 학생들의 학습태도를 적극적으로 변화시킨다는 점을 확인하였다. 성별에 따른 학습태도 점수는 남학생이 여학생에 비해 유의미하게 높았으나, 그 차이는 미미한 것으로 나타났다. 또 교과별로 비교할 때 과학, 미술, 재량활동 과목에서 특히 더욱 효과가 있는 것으로 나타났다. 이러한 결과는 첫째, 로봇활용수업이 실제적인 과제와 실천 중심의 교수 학습 환경을 바탕으로 과제에 대한 주인의식과 내적동기를 북돋우기 용이하다는 점과, 둘째, 로봇매체의 교육적 장점을 극대화하고 그에 따른 적절한 수업환경을 제공한 데서 연유한 것으로 판단된다.

• 제어로봇시스템학회논문지
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• 제8권7호
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• pp.607-612
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• 2002

An automatic design method of behaviors in behavior-based robotics is proposed. With this method, a robot can design its behaviors by itself without aids of human designer. Automating design procedure of behaviors can make the human designer free from somewhat tedious endeavor that requires to predict all possible situations in which the robot will work and to design a suitable behavior for each situation. A simple reinforcement learning strategy is the main frame of this method and the key parameter of the learning process is significant change of reward value. A successful application to mobile robot navigation is reported too.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.9-11
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• 2022

Applying Reinforcement Learning in everyday applications and varied environments has proved the potential of the of the field and revealed pitfalls along the way. In robotics, a learning agent takes over gradually the control of a robot by abstracting the navigation model of the robot with its inputs and outputs, thus reducing the human intervention. The challenge for the agent is how to implement a feedback function that facilitates the learning process of an MDP problem in an environment while reducing the time of convergence for the method. In this paper we will implement a reward shaping system avoiding sparse rewards which gives fewer data for the learning agent in a ROS environment. Reward shaping prioritizes behaviours that brings the robot closer to the goal by giving intermediate rewards and helps the algorithm converge quickly. We will use a pseudocode implementation as an illustration of the method.

• 대한안전경영과학회지
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• 제23권4호
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• pp.93-104
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• 2021

In this paper, we propose a method for diagnosing overload and working load of collaborative robots through performance analysis of machine learning algorithms. To this end, an experiment was conducted to perform pick & place operation while changing the payload weight of a cooperative robot with a payload capacity of 10 kg. In this experiment, motor torque, position, and speed data generated from the robot controller were collected, and as a result of t-test and f-test, different characteristics were found for each weight based on a payload of 10 kg. In addition, to predict overload and working load from the collected data, machine learning algorithms such as Neural Network, Decision Tree, Random Forest, and Gradient Boosting models were used for experiments. As a result of the experiment, the neural network with more than 99.6% of explanatory power showed the best performance in prediction and classification. The practical contribution of the proposed study is that it suggests a method to collect data required for analysis from the robot without attaching additional sensors to the collaborative robot and the usefulness of a machine learning algorithm for diagnosing robot overload and working load.

• 로봇학회논문지
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• 제18권3호
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• pp.352-357
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• 2023

Since robotic assembly in an unstructured environment is very difficult with existing control methods, studies using artificial intelligence such as reinforcement learning have been conducted. However, since long-time operation of a robot for learning in the real environment adversely affects the robot, so a method to shorten the learning time is needed. To this end, a method based on a pre-trained neural network was proposed in this study. This method showed a learning speed about 3 times than the existing methods, and the stability of reward during learning was also increased. Furthermore, it can generate a more optimal policy than not using a pre-trained neural network. Using the proposed reinforcement learning-based assembly trajectory generator, 100 attempts were made to assemble the power connector within a random error of 4.53 mm in width and 3.13 mm in length, resulting in 100 successes.

• 전기학회논문지P
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• 제57권2호
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• pp.109-114
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• 2008

In this paper, a dynamic learning controller for robot manipulator is implemented using real-time operating system with capabilities of multitasking, intertask communication and synchronization, event-driven, priority-driven scheduling, real-time clock control, etc. The controller hardware system with VME bus and related devices is developed and applied to implement a dynamic learning control scheme for robot manipulator. Real-time performance of the proposed dynamic learning controller is tested and evaluated for tracking of the desired trajectory and compared with the conventional servo controller.

• Advances in robotics research
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• 제2권1호
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• pp.13-31
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• 2018

This paper presents the performance of Teaching-Learning-Based Optimization (TLBO) algorithm for optimum static balancing of a robot manipulator. Static balancing of robot manipulator is an important aspect of the overall robot performance and the most demanding process in any robot system to match the need for the production requirements. The average force on the gripper in the working area is considered as an objective function. Length of the links, angle between them and stiffness of springs are considered as the design variables. Three robot manipulator configurations are optimized. The results show the better or competitive performance of the TLBO algorithm over the other optimization algorithms considered by the previous researchers.