• 로봇학회논문지
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• 제17권4호
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• pp.407-416
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• 2022

Multiple AMRs have been proved to be effective in improving warehouse productivity by eliminating workers' wasteful walking time. Although Multi-agent Path Finding (MAPF)-based solution is an optimal approach for this task, its deployment in practice is challenging mainly due to its imperfect plan-execution capabilities and insufficient computing resources for high-density environments. In this paper, we present a MAPF-based fleet management system architecture that robustly manages multiple robots by re-computing their paths whenever it is necessary. To achieve this, we defined four events that trigger our MAPF solver framework to generate new paths. These paths are then delivered to each AMR through ROS2 message topic. We also optimized a graph structure that effectively captures spatial information of the warehouse. By using this graph structure we can reduce computational burden while keeping its rescheduling functionality. With proposed MAPF-based fleet management system, we can control AMRs without collision or deadlock. We applied our fleet management system to the real logistics warehouse with 10 AMRs and observed that it works without a problem. We also present the usage statistic of adopting AMRs with proposed fleet management system to the warehouse. We show that it is useful over 25% of daily working time.

• 한국정보통신학회논문지
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• 제13권8호
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• pp.1483-1490
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• 2009

본 논문에서는 수정된 유전자 알고리즘과 퍼지 추론 시스템을 이용한 무인 자율주행 이송장치의 다중경로계획을 연구하였다. 기존의 다중경로계획을 위한 방법으로는 최적화 알고리즘들을 이용한 작업별회귀 방법과 매시간 각 개체마다 경로를 재계획하는 방법이 있다. 이러한 방법들은 한 대의 이송장치가 작업을 하기 위해서는 한 대 이상의 이송장치가 정지해야하므로 시간과 에너지 측면에서 비효율적이며, 연산량이 많아 오류가 발생할 가능성이 있다. 본 논문에서는 이러한 문제점들을 해결하기 위해 수정된 유전자 알고리즘과 퍼지 추론 시스템을 이용한 다중경로계획을 제안한다. 제안한 알고리즘의 성능 평가를 위하여 무인 자율주행이 가능한 2대의 이송장치를 설계 제작하였고 지게차와 동일한 주행 제어부를 탑재하여 다중경로계획을 실험하였다. 실험 결과, 빠르고 최적화된 경로 계획과 효율적인 충돌 회피가 가능함을 확인 할 수 있었다.

• 지능정보연구
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• 제17권1호
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• pp.53-69
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• 2011

로봇 자체 또는 로봇에 탑재된 콘텐츠와의 상호작용을 위해 일반적으로 영상 또는 음성 인식 기술이 사용된다. 그러나 영상 음성인식 기술은 아직까지 기술 및 환경 측면에서 해결해야 할 어려움이 존재하며, 실적용을 위해서는 사용자의 협조가 필요한 경우가 많다. 이로 인해 로봇과의 상호작용은 터치스크린 인터페이스를 중심으로 개발되고 있다. 향후 로봇 서비스의 확대 및 다양화를 위해서는 이들 영상 음성 중심의 기존 기술 외에 상호보완적으로 활용이 가능한 인터페이스 기술의 개발이 필요하다. 본 논문에서는 로봇 인터페이스 활용을 위한 가속도 센서 기반의 제스처 인식 기술의 개발에 대해 소개한다. 본 논문에서는 비교적 어려운 문제인 26개의 영문 알파벳 인식을 기준으로 성능을 평가하고 개발된 기술이 로봇에 적용된 사례를 제시하였다. 향후 가속도 센서가 포함된 다양한 장치들이 개발되고 이들이 로봇의 인터페이스로 사용될 때 현재 터치스크린 중심으로 된 로봇의 인터페이스 및 콘텐츠가 다양한 형태로 확장이 가능할 것으로 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4084-4104
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• 2021

Visual place recognition (VPR) is a fundamental yet challenging task of mobile robot navigation and localization. The existing VPR methods are usually based on some pairwise similarity of image descriptors, so they are sensitive to visual appearance change and also computationally expensive. This paper proposes a simple yet effective four-step method that achieves adaptive convolutional neural network (CNN) landmark matching for VPR. First, based on the features extracted from existing CNN models, the regions with higher significance scores are selected as landmarks. Then, according to the coordinate positions of potential landmarks, landmark matching is improved by removing mismatched landmark pairs. Finally, considering the significance scores obtained in the first step, robust image retrieval is performed based on adaptive landmark matching, and it gives more weight to the landmark matching pairs with higher significance scores. To verify the efficiency and robustness of the proposed method, evaluations are conducted on standard benchmark datasets. The experimental results indicate that the proposed method reduces the feature representation space of place images by more than 75% with negligible loss in recognition precision. Also, it achieves a fast matching speed in similarity calculation, satisfying the real-time requirement.

• Journal of Astronomy and Space Sciences
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• 제29권4호
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• pp.381-387
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• 2012

The planetary exploration rover executes various missions after moving to the target point in an unknown environment in the shortest distance. Such missions include the researches for geological and climatic conditions as well as the existence of water or living creatures. If there is any obstacle on the way, it is detected by such sensors as ultrasonic sensor, infrared light sensor, stereo vision, and laser ranger finder. After the obtained data is transferred to the main controller of the rover, decisions can be made to either overcome or avoid the obstacle on the way based on the operating algorithm of the rover. All the planetary exploration rovers which have been developed until now receive the information of the height or width of the obstacle from such sensors before analyzing it in order to find out whether it is possible to overcome the obstacle or not. If it is decided to be better to overcome the obstacle in terms of the operating safety and the electric consumption of the rover, it is generally made to overcome it. Therefore, for the purpose of carrying out the planetary exploration task, it is necessary to design the proper suspension system of the rover which enables it to safely overcome any obstacle on the way on the surface in any unknown environment. This study focuses on the design of the new double 4-bar linkage type of suspension system applied to the Korea Aerospace Research Institute rover (a tentatively name) that is currently in the process of development by our institute in order to develop the planetary exploration rover which absolutely requires the capacity of overcoming any obstacle. Throughout this study, the negative moment which harms the capacity of the rover for overcoming an obstacle was induced through the dynamical modeling process for the rocker-bogie applied to the Mars exploration rover of the US and the improved version of rocker-bogie as well as the suggested double 4-bar linkage type of suspension system. Also, based on the height of the obstacle, a simulation was carried out for the negative moment of the suspension system before the excellence of the suspension system suggested through the comparison of responding characteristics was proved.