Earticle

This paper describes a low-complexity collision avoidance system for automated guided vehicles (AGVs) based on active ultra-wide band (UWB) modules. In particular, we consider an industrial warehouse where all the AGVs and target nodes (TNs) (e.g., people) are equipped with active UWB modules. A communication session between a pair of UWB modules permits the exchange of information and the estimation of the distance between them. The UWB module positioned on an AGV is connected to an on-board computer; whenever the UWB module on an AGV receives a message from a TN, it communicates all the received data to the on-board computer that can decide to stop the AGV if the range estimate is below a given threshold. This prevents undesired collisions between the AGV and the TN. In this paper, we present the experimental results of the proposed collision avoidance system obtained using the UWB modules, PulsON 410 ranging and communication modules (P410 RCMs), produced by Time Domain.

In this paper, we propose a soft actor?critic (SAC) algorithm with hindsight experience replay (HER), called SACHER, which is a class of deep reinforcement learning (DRL) algorithm. SAC is an off-policy model-free DRL algorithm that outperforms earlier DRL algorithms in terms of exploration and robustness. However, in SAC, maximizing the entropy-augmented objective degrades the optimality of learning outcomes. We propose SACHER to improve the learning performance of SAC. We apply SACHER to the path planning and collision avoidance control of unmanned aerial vehicles (UAVs). We demonstrate the effectiveness of SACHER in terms of the success rate, learning speed, and collision avoidance performance of UAV operation.

In this paper, we will consider the problem of multi-unmanned aerial vehicles (UAVs) deployment among users’ hotspots. UAVs carry reconfigurable intelligent surface (RIS) boards to strengthen millimeter wave (mmWave) coverage at these hotspots. UAVs should maximize hotspots’ sum data rates while minimizing their flights’ cost, i.e., hovering and flying energy consumptions. Moreover, collisions should be avoided among UAVs, i.e., one hotspot should be served by only one UAV at a time. In this paper, this problem is considered as a multi-player multi-armed bandit (MP-MAB) game with budget constraint and collision avoidance. In this context, budget constraint Thompson sampling (TS) with collision avoidance MAB algorithm (BTSCA-MAB) is proposed to efficiently implement the formulated MP-MAB game. Numerical analysis confirms the superior performance of the proposed BTSCA-MAB over other benchmarks.

본 연구에서는 운전자들이 경험한 상태운전분노가 운전자의 상황인식과 추돌회피 수행에 어떠한 영향을 미치는지, 그리고 상황인식에 대한 상태운전분노의 효과를 긍정/부정정서가 어떻게 조절하는지 운전 시뮬레이션을 통해 살펴보았다. 본 실험에는 63명의 대학생 운전자들이 참여하였다. 본 연구의 주요결과를 정리하면 다음과 같다. 첫째, 상태운전분노 수준에 따라 추돌위험 가능상황에서 실제 추돌사고를 야기했는지의 여부를 분석한 결과, 상태운전분노를 높은 수준으로 경험한 실험참가자들은 그렇지 않은 실험참가자들에 비해 선행차량과의 추돌비율이 유의하게 높았다. 둘째, 상황인식 측정점수에 대한 특성운전분노와 긍정/부정정서의 주효과는 각각 유의하지 않았다. 셋째, 상태운전분노 수준이 높을수록 전반적으로 상태운전분노 유발 이후의 상황인식 점수가 유의하게 낮아지기는 하였으나 이러한 경향은 부정정서가 높은 경우에 더 두드러져 상태운전분노에 의한 상황인식에서의 저하는 운전자의 부정정서 점수가 높을수록 더 컸다. 이러한 결과들은 운전자의 특성운전분노보다는 상태운전분노가 운전자의 상황인식 능력 저하와 유의한 관련성이 있고, 특히 운전자의 상태운전분노가 상황인식에 대해 갖는 효과는 부정정서와 같은 정서-관련변인을 통합적으로 고려할 경우 더 타당하게 설명될 수 있다는 것을 시사한다.

This driving simulation study examined the effect of driver's state driving anger(SDA) on collision avoidance(CA) and situation awareness(SA), as well as the moderating effect of driver's positive and negative affect(PA and NA) on the relationship between the driver's SDA and SA. The results showed the followings. First, high SDA group collided with the leading vehicle more frequently than low SDA group. Second, neither the driver's trait driving anger(TDA) nor PA/NA yielded significant changes in SA after SDA was induced. Third, high SDA tended to lower SA but this tendency was observed only when the driver's NA was high. These results suggested that SDA than TDA is a significant deteriorating factor of the driver's SA, and more importantly, SDA should be considered with other affect-relating variable such as NA in explaining the effect of SDA on driver's SA and CA.

Robots for a wide range of purposes have been developed along with the rapid industrialization. On the basis of higher convenience, the robots have been creating new industrial environment. The robots are generally classified into service robots and industrial robots. Robots in various shapes have been developed on the basis of the autonomous mobile robots. The autonomous mobile robots have the possibility to crash against any object in their moving range. This paper suggests a collision avoidance method to prevent collision of robots. The collision avoidance method analyzes the road context data and makes a robot move to a safe area. The collision avoidance method proposed in this paper converts the road context data into the information value. The collision avoidance method analyzes the present risk on the basis of the converted information value. The collision avoidance method makes a robot move to a safe area when crash is estimated by the information analysis.

해양 분야에서는 인력 부족과 인건비 증가 등의 문제를 해결하기 위하여 무인 운영 체제에 대한 다양한 연구가 진행 중이 다. 해군에서도 인력 감소 대처와 승무원의 안전 보장을 위해 무인 체계에 대한 관심을 보이고 있다. 본 논문은 무인 함정 체계의 자율운항 기술 중 핵심 기술인 충돌 회피 알고리즘 개발을 목적으로 한다. 충돌 회피 알고리즘은 운항 시 조우할 수 있는 정적 장애물과 동적 장애물을 모두 회피할 수 있어야 하며, 센서의 사용이 제한되는 상황에서도 장애물을 회피할 수 있 어야 한다. 이러한 알고리즘을 개발하기 위해 함정의 ACDIS 추출 데이터와 AIS 데이터를 이용하며, Vector Field Histogram(VFH)과 Velocity Obstacle method(VO)를 융합하여 충돌 회피 알고리즘을 개발하였다. 이를 검증하기 위해 MMG 수학모델을 이용한 시뮬레이션 환경을 구축하였으며, 제시한 알고리즘을 이용할 경우 정적 장애물, 동적 장애물, 두 가 지 장애물을 동시에 조우하는 상황에서도 충돌 회피가 가능함을 시뮬레이션을 통해 확인하였다.

In the maritime industry, various research is underway to address issues such as labor shortages and increasing labor costs by developing unmanned operating systems. The Navy is also showing interest in unmanned systems to cope with manpower reduction and ensure the safety of crew members. This paper aims to develop collision avoidance algorithms, a key technology in autonomous navigation systems for unmanned surface vehicles. The collision avoidance algorithm should be able to avoid both static and dynamic obstacles that may be encountered during navigation, even in situations where sensor use is limited. To develop such an algorithm, ACDIS extraction data and AIS data were utilized, and a collision avoidance algorithm was developed by integrating the Vector Field Histogram (VFH) and Velocity Obstacle method (VO). To validate the proposed algorithm, a simulation environment was created using the MMG mathematical model, and through simulations, it was confirmed that collision avoidance is possible even in situations where static obstacles, dynamic obstacles, and both types of obstacles are encountered simultaneously.

본 논문은 무선 채널을 노드에게 할당하여 보장하는 GTS 기반의 무선 센서 네트워크에서 다수의 노드가 같은 채널 을 공유할 때, 충돌이 발생하는 것을 최대로 억제하기 위한 방안을 제시한다. 무선 자원이 충분하지 않은 조건에서 다 수의 노드에게 특정 채널을 같이 할당하고, 할당한 채널을 노드들이 공유하면서 데이터를 전송한다. 데이터 전송 시, 한 개 이상의 노드들이 채널을 이용하면 충돌이 발생한다. 이러한 충돌을 효과적으로 줄이기 위해, 부모가 자식 노드들에 게 백오프 값들을 지정하고, 그래도 충돌이 생기는 경우, 백오프 값 변경을 시도하여 충돌을 방지한다. 제안 방안을 시 뮬레이션을 통해 제안 방안이 효과적으로 백오프 값을 조절하여 충돌이 많이 감소함을 확인할 수 있었다.

This paper presents a collision avoidance scheme for wireless sensor networks that use a GTS-based channel allocation scheme. Many sensor nodes can share a GTS channel for sending their data to the sink node. When a node tries to send a frame at a shared GTS channel, a collision can be occurred when there is a node that uses the same backoff number. For decreasing a wireless collision, the parent assigns a backoff number when a child node registers to it. Further, when a collision occurs during a data transfer, the parent node reassigns a new backoff number for the child node. Simulation results show that there is a decreased collision number with suggested parent-controlled collision avoidance scheme by effectively controlling the backoff number of the child.

This study analyzes parking accident types and evaluates the performance of the Parking Autonomous Emergency Braking (P-AEB) system. A total of 4,071 real-world black box accident cases were analyzed, revealing that rearward parking accidents occur approximately four times more frequently than forward ones. Additionally, 79.1% of parking accidents involved collisions with stationary vehicles. The most common accident types were non-steering rearward collisions (34.0%), steering rearward diagonal collisions (24.2%), and non-steering diagonal rearward collisions (16.2%). The P-AEB performance evaluation followed the RCAR guidelines, testing 18 scenarios (6 forward, 12 rearward collisions). Results indicate that higher speeds increase the likelihood of rearward collisions, and all vehicles failed to avoid collisions in diagonal rearward parking scenarios. Additionally, P-AEB did not activate when entering forward while turning left, resulting in collisions. This study confirms that P-AEB performance varies depending on the installed system and parking environment, and in some situations, current technology may not fully prevent accidents. Future research should focus on enhancing P-AEB sensor detection and evaluation methods to improve real-world accident prevention effectiveness.

자율주행 차량은 레이더, 라이다 카메라 등 다양한 로컬 센서들을 활용하여 주변 환경을 인지하고 판단하여 주행한다. 하지만 로컬 센서만을 활용하여 주행할 경우 인지 범위 한계로 장애물에 가려진 보행자나 자전거와 같은 VRU(Vulnerable Road User, 취약 도로 사용자)의 거 동 정보를 예측하기 어렵다. 본 논문에서는 이러한 로컬 센서의 한계를 극복하기 위해 V2X 통신 정보를 활용한 VRU 충돌 회피 알고리즘을 개발하였다. 알고리즘은 인프라로부터 충돌 위험이 있는 VRU의 정보를 전달 받아 미래 거동을 예측하고 주변 환경에 따라 적절하게 조향 및 제동 회피를 수행하도록 설계하였다. 개발된 알고리즘을 검증하기 위하여 다양한 조건의 시나리오에서 시뮬레이션을 수행하였으며, 그 결과, 기존 로컬 센서 정보만을 활용하였을 때 보다 개선된 충돌 회피 성능을 보일 뿐만 아니라, 차량의 안정성 또한 확보할 수 있음을 확인 하였다.

Autonomous vehicles use various local sensors such as camera, radar, and lidar to perceive the surrounding environment. However, it is difficult to predict the movement of vulnerable road users using only local sensors that are subject to limits in cognitive range. This is true especially when these users are blocked from view by obstacles. Hence, this paper developed an algorithm for collision avoidance with VRU using V2X information. The main purpose of this collision avoidance system is to overcome the limitations of the local sensors. The algorithm first evaluates the risk of collision, based on the current driving condition and the V2X information of the VRU. Subsequently, the algorithm takes one of four evasive actions; steering, braking, steering after braking, and braking after steering. A simulation was performed under various conditions. The results of the simulation confirmed that the algorithm could significantly improve the performance of the collision avoidance system while securing vehicle stability during evasive maneuvers.

지상 무인 차량(UGV), 무인기(UAV), 무인수상정(USV), 무인잠수정(UUV), 로봇 등과 같은 다중 무인체가 대형을 이루면서 군집 주행을 할 때 충돌회피 문제는 다중 에이전트 시스템에서 기본적으로 구현해야 하는 것으로 중요하게 인식되었다. 다중무 인체들은 가까운 미래에 생화학 오염지역이나 위험한 전투지역에서의 신속하게 투입되어 주어진 임무를 수행할 것이다. 다중 무인체가 편대를 이루어 출발지점에서 목표점인 임무 지역으로 이동할 때 자율주행을 할 수 있는 선도-추종 대형제 어를 적용하고, 다중무인체가 군집 자율주행할 때 갑자기 동적장애물 등이 나타나거나 주행 경로상에 고정장애물이 존재할 경우 이를 회피하기 위해 인공전위장을 이용한다. 지상전에서 다중 무인체의 장애물 회피 시스템에 대한 대형제어 알고리즘 성능을 평가하기 위해, 다중 무인체가 각각 3대, 5대, 7대, 그리고 장애물이 각각 0개, 1개, 3개, 5개인 경우에 대해 이들을 조합한 여러 가지 군집 자율주행상황을 시뮬레이션하였다.

It has been importantly recognized that the collision avoidance problem of multiple unmanned vehicles(MUVs) such as UGV, UAV, USV, UUV, Robot, etc. for platoon autonomous navigation in dynamic environments should be implemented basically in multiple agent systems. In the near future, they will be dispatched quickly and carry out their assigned tasks in biochemical contaminated area or dangerous combant areas. When multiple unmanned vehicles form a platoon formation and move from the starting point to the target point, leader-follower formation control that can autonomously navigate is applied. When multiple unmanned vehicles are autonomously driving in clusters, if a dynamic obstacle suddenly appears or there is a fixed obstacle on the driving path, artificial potential is used to avoid them. In order to check the performance of the formation control algorithm for the obstacle avoidance system of multiple unmanned vehicles in ground warfare, in the case of multiple unmanned vehicles with 3, 5, 7, and 0, 1, 3, and 5 obstacles, respectively, various platooning autonomous navigation situations were simulated by combining them.

최근 횡단보도 및 교차로에서 보행자 충돌사고 예방의 중요성이 증가하고 있다. C-ITS 서비 스에서 이러한 사고를 줄이기 위하여 보행자 충돌방지 경고 서비스를 제시하고 있다. 그러나 현재 C-ITS 표준에 따른 보행자 충돌방지 경고 서비스는 현장의 카메라에서 보행자를 바로 검 출하여 서비스를 제공하는 것이 아니라 관제 센터의 영상분석 서버에서 보행자를 검출하고 ITS 시스템과 연계하여 서비스를 제공하기 때문에 실시간성을 만족하기 어렵다. 본 논문에서 는 엣지 카메라를 이용하여 현장에서 보행자를 검출하고 검출결과를 V2X 인프라를 통해 바로 운전자에게 제공하는 보행자 충돌방지 경고 시스템을 제안하고, 구현한 후 성능 평가를 시행 하였다. 평가 결과, 최악의 상황에서도 보행자 충돌방지 경고 메시지를 C-ITS 표준에서 요구하 고 있는 300ms 이내의 지연시간을 만족하여 전달할 수 있음을 확인하였다.

The prevention of pedestrian accidents in crosswalks and intersections is very important. The C-ITS services provide a warning service for preventing accidents between cars and pedestrians. In the current pedestrian collision prevention warning service according to the C-ITS standard, however, it is difficult to provide real-time service because it detects pedestrians from a video-analysis server in the control center and sends service messages through the ITS system. This paper proposes a pedestrian collision-prevention warning system that detects pedestrians in the local field using an edge camera and sends a warning message directly to the driver through a roadside unit. An evaluation showed that the proposed system could deliver the pedestrian collision prevention-warning message to the driver satisfying the delay time within the 300 ms required by the C-ITS standard, even in the worst case.

Recently, as the field of use of MAVs in modern society has become wider, research on MAV flight control is attracting more attention. In environmental monitoring, the diversity of its forms and applications is gradually widening, such as terrain modeling based on aerial digital image data, surveillance of private protection facilities, aerial surveillance for military purposes, and utilization of delivery services in the commercial sector. Among related studies, proposals related to autonomous flight, which can follow a number of pre-determined route points and perform missions without human intervention, have increased. The importance of the aircraft electrical system fault detection is also growing because of mounting equipment and aircraft demand has increased significantly to an increase in facility that use electricity as large and modernize. This paper estimates the qualitative fault possible cause through previous studies of the actual fault cases that do not have external power Boeing 737 aircraft supply, were detected fault through experimentation, validation with the electrical system fault detection via ground and aircraft equipped inspection the study was carried out.