A Survey and Analysis of Multi-Robot Coordination

International audienceIn the field of mobile robotics, the study of multi-robot systems (MRSs) has grown significantly in size and importance in recent years. Having made great progress in the development of the basic problems concerning single-robot control, many researchers shifted their focus to the study of multi-robot coordination. This paper presents a systematic survey and analysis of the existing literature on coordination, especially in multiple mobile robot systems (MMRSs). A series of related problems have been reviewed, which include a communication mechanism, a planning strategy and a decision-making structure. A brief conclusion and further research perspectives are given at the end of the paper

Traffic control for a swarm of robots:avoiding target congestion

One of the main problems in the navigation of robotic swarms is when several robots try to reach the same target at the same time, causing congestion situations that may compromise performance. In this paper, we propose a distributed coordination algorithm to alleviate this type of congestion. Using local sensing and communication, and controlling their actions using a probabilistic finite state machine, robots are able to coordinate themselves to avoid these situations. Simulations and real experiments were executed to study the performance and effectiveness of the proposed algorithm. Results show that the algorithm allows the swarm to have a more efficient and smoother navigation and is suitable for large groups of robots

Mobile Robots

The objective of this book is to cover advances of mobile robotics and related technologies applied for multi robot systems' design and development. Design of control system is a complex issue, requiring the application of information technologies to link the robots into a single network. Human robot interface becomes a demanding task, especially when we try to use sophisticated methods for brain signal processing. Generated electrophysiological signals can be used to command different devices, such as cars, wheelchair or even video games. A number of developments in navigation and path planning, including parallel programming, can be observed. Cooperative path planning, formation control of multi robotic agents, communication and distance measurement between agents are shown. Training of the mobile robot operators is very difficult task also because of several factors related to different task execution. The presented improvement is related to environment model generation based on autonomous mobile robot observations

Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

Cooperative collision avoidance for unmanned aerial vehicles

Thesis (MEng)--Stellenbosch University, 2020.ENGLISH ABSTRACT: This thesis presents the design, implementation, and verification of a cooperative collision avoidance algorithms for unmanned aerial vehicles (UAVs) in multi-aircraft conflict scenarios. Two types of collision avoidance algorithms are developed and verified in simulation: a rules-based algorithm and a cooperative path planning based algorithm. The rules-based collision avoidance algorithm is modelled after the tactical Traffic Collision Avoidance System (TCAS) that is used on commercial passenger airliners. To enable multi-aircraft collision avoidance, two methods for combining the pairwise rulesbased collision avoidance actions are proposed, namely Resolution Action Superposition (RAS) and pairwise Closest-Intruder-First (CIF). The path planning based collision avoidance algorithm grows a search tree of admissible conflict resolution paths, and searches the tree to find the conflict-free path with the lowest cost. To enable cooperative collision avoidance, all aircraft communicate their current positions and intended flight paths to all other aircraft. A token allocation strategy is used so that the individual aircraft plan their new collision avoidance paths sequentially according to a predetermined priority order. The rules-based and path planning based collision avoidance algorithms were implemented and verified in simulation. A simulation environment was created to test both the rules-based and path planning based collision avoidance algorithms. Set-piece conflict avoidance scenarios were performed to produce illustrative results. The simulations illustrated that both rules-based and path planning based collision avoidance can resolve both pairwise and multi-aircraft conflicts. Furthermore, Monte Carlo simulations were performed to produce statistical results and evaluate the performance of both algorithms in random conflict scenarios. The simulation results show that both the rules-based and path planning based solutions are able to successfully resolve collision scenarios involving multiple unmanned aerial vehicles. The rules-bases solution requires less computational effort but does not optimise the collision avoidance plans. The path planning based solution requires much more computational effort, but provides optimal solutions that minimises the deviation from the original flights, and minimises the control effort of the avoidance actions.AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwerp, implementasie, en verifikasie van samewerkende botsingvermyding algoritmes vir onbemande vliegtuie (UAVs) in multi-vliegtuig konflik scenarios. Twee tipes botsingvermyding algoritmes word ontwikkel en getoets in simulasie: ’n reëls-gebaseerde algoritme en ’n padbeplanning-gebaseerde algoritme. Die reëls-gebaseerde algoritme word gemodelleer na die taktiese Traffic Collision Avoidance System (TCAS) wat gebruik word op kommersiële passasiersvliegtuie. Om multivliegtuig botsingvermyding te bewerkstellig, word twee metodes voorgestel om die paarsgewyse reëls-gebaseerde botsingvermyding aksies te kombineer, naamlik Resolusie Aksie Superposisie (RAS) en Naaste-Indringer-Eerste (NIE). Die padbeplanning-gebaseerde botsingvermyding algoritme groei ’n soektogboom van toelaatbare botsingvermyding paaie, en deursoek dan die boom om die botsingvrye pad met die laagste koste te vind. Om samewerkende botsingvermyding te bewerkstellig, kommunikeer al die vliegtuie hulle huidige posisies en beplande vlugpaaie aan al die ander vliegtuie. ’n Token allokering strategie word gebruik sodat individuele vliegtuie hulle nuwe botsingvermyding paai sekwensieël beplan volgens ’n voorafbepaalde prioriteit volgorde. Die reëls-gebaseerde en padbeplanning-gebaseerde botsingvermyding algoritmes is geïmplimenteer en getoets in simulasie. ’n Simulasie omgewing is geskep om beide die reëlsgebaseerde en padbeplanning-gebaseerde algoritmes te toets. Vooropgestelde botsingvermyding scenarios is uitgevoer om illustratiewe resultate te verkry. Die simulasies illustreer dat beide die revls-gebaseerde en padbeplanning-gebaseerde algoritmes in staat is beide paarsgewyse en multi-vliegtuig konflikte op te los. Monte Carlo simulasies is uitgevoer om statistiese resultate te lewer om die vermoë van beide algoritmes in lukrake konflik scenarios te evalueer. Die Monte Carlo simulasies wys dat beide die reëls-gebaseerde en padbeplanning-gebaseerde benaderings suksesvol lukrake multi-vliegtuig konflikte kan oplos. Die reëls-gebaseerde benadering vereis minder verwerkingskrag, maar optimiseer nie die botsinvermyding paaie nie. Die padbeplanning-gebaseerde benadering vereis meer verwerkingskrag, maar verskaf optimale oplossings wat die afwyking van die vliegtuie van hulle oorspronklike vlugplanne minimeer, en ook die beheerenergie van die vermydingsaksies minimeer.Master

A survey of formation control and motion planning of multiple unmanned vehicles

The increasing deployment of multiple unmanned vehicles systems has generated large research interest in recent decades. This paper therefore provides a detailed survey to review a range of techniques related to the operation of multi-vehicle systems in different environmental domains, including land based, aerospace and marine with the specific focuses placed on formation control and cooperative motion planning. Differing from other related papers, this paper pays a special attention to the collision avoidance problem and specifically discusses and reviews those methods that adopt flexible formation shape to achieve collision avoidance for multi-vehicle systems. In the conclusions, some open research areas with suggested technologies have been proposed to facilitate the future research development

Pedestrian Trajectory Prediction in Pedestrian-Vehicle Mixed Environments: A Systematic Review

Planning an autonomous vehicle's (AV) path in a space shared with pedestrians requires reasoning about pedestrians' future trajectories. A practical pedestrian trajectory prediction algorithm for the use of AVs needs to consider the effect of the vehicle's interactions with the pedestrians on pedestrians' future motion behaviours. In this regard, this paper systematically reviews different methods proposed in the literature for modelling pedestrian trajectory prediction in presence of vehicles that can be applied for unstructured environments. This paper also investigates specific considerations for pedestrian-vehicle interaction (compared with pedestrian-pedestrian interaction) and reviews how different variables such as prediction uncertainties and behavioural differences are accounted for in the previously proposed prediction models. PRISMA guidelines were followed. Articles that did not consider vehicle and pedestrian interactions or actual trajectories, and articles that only focused on road crossing were excluded. A total of 1260 unique peer-reviewed articles from ACM Digital Library, IEEE Xplore, and Scopus databases were identified in the search. 64 articles were included in the final review as they met the inclusion and exclusion criteria. An overview of datasets containing trajectory data of both pedestrians and vehicles used by the reviewed papers has been provided. Research gaps and directions for future work, such as having more effective definition of interacting agents in deep learning methods and the need for gathering more datasets of mixed traffic in unstructured environments are discussed.Comment: Published in IEEE Transactions on Intelligent Transportation System