45 research outputs found

    Computational Intelligence for Cooperative Swarm Control

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    Over the last few decades, swarm intelligence (SI) has shown significant benefits in many practical applications. Real-world applications of swarm intelligence include disaster response and wildlife conservation. Swarm robots can collaborate to search for survivors, locate victims, and assess damage in hazardous environments during an earthquake or natural disaster. They can coordinate their movements and share data in real-time to increase their efficiency and effectiveness while guiding the survivors. In addition to tracking animal movements and behaviour, robots can guide animals to or away from specific areas. Sheep herding is a significant source of income in Australia that could be significantly enhanced if the human shepherd could be supported by single or multiple robots. Although the shepherding framework has become a popular SI mechanism, where a leading agent (sheepdog) controls a swarm of agents (sheep) to complete a task, controlling a swarm of agents is still not a trivial task, especially in the presence of some practical constraints. For example, most of the existing shepherding literature assumes that each swarm member has an unlimited sensing range to recognise all other members’ locations. However, this is not practical for physical systems. In addition, current approaches do not consider shepherding as a distributed system where an agent, namely a central unit, may observe the environment and commu- nicate with the shepherd to guide the swarm. However, this brings another hurdle when noisy communication channels between the central unit and the shepherd af- fect the success of the mission. Also, the literature lacks shepherding models that can cope with dynamic communication systems. Therefore, this thesis aims to design a multi-agent learning system for effective shepherding control systems in a partially observable environment under communication constraints. To achieve this goal, the thesis first introduces a new methodology to guide agents whose sensing range is limited. In this thesis, the sheep are modelled as an induced network to represent the sheep’s sensing range and propose a geometric method for finding a shepherd-impacted subset of sheep. The proposed swarm optimal herding point uses a particle swarm optimiser and a clustering mechanism to find the sheepdog’s near-optimal herding location while considering flock cohesion. Then, an improved version of the algorithm (named swarm optimal modified centroid push) is proposed to estimate the sheepdog’s intermediate waypoints to the herding point considering the sheep cohesion. The approaches outperform existing shepherding methods in reducing task time and increasing the success rate for herding. Next, to improve shepherding in noisy communication channels, this thesis pro- poses a collaborative learning-based method to enhance communication between the central unit and the herding agent. The proposed independent pre-training collab- orative learning technique decreases the transmission mean square error by half in 10% of the training time compared to existing approaches. The algorithm is then ex- tended so that the sheepdog can read the modulated herding points from the central unit. The results demonstrate the efficiency of the new technique in time-varying noisy channels. Finally, the central unit is modelled as a mobile agent to lower the time-varying noise caused by the sheepdog’s motion during the task. So, I propose a Q-learning- based incremental search to increase transmission success between the shepherd and the central unit. In addition, two unique reward functions are presented to ensure swarm guidance success with minimal energy consumption. The results demonstrate an increase in the success rate for shepherding

    CernoCAMAL : a probabilistic computational cognitive architecture

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    This thesis presents one possible way to develop a computational cognitive architecture, dubbed CernoCAMAL, that can be used to govern artificial minds probabilistically. The primary aim of the CernoCAMAL research project is to investigate how its predecessor architecture CAMAL can be extended to reason probabilistically about domain model objects through perception, and how the probability formalism can be integrated into its BDI (Belief-Desire-Intention) model to coalesce a number of mechanisms and processes. The motivation and impetus for extending CAMAL and developing CernoCAMAL is the considerable evidence that probabilistic thinking and reasoning is linked to cognitive development and plays a role in cognitive functions, such as decision making and learning. This leads us to believe that a probabilistic reasoning capability is an essential part of human intelligence. Thus, it should be a vital part of any system that attempts to emulate human intelligence computationally. The extensions and augmentations to CAMAL, which are the main contributions of the CernoCAMAL research project, are as follows: - The integration of the EBS (Extended Belief Structure) that associates a probability value with every belief statement, in order to represent the degrees of belief numerically. - The inclusion of the CPR (CernoCAMAL Probabilistic Reasoner) that reasons probabilistically over the goal- and task-oriented perceptual feedback generated by reactive sub-systems. - The compatibility of the probabilistic BDI model with the affect and motivational models and affective and motivational valences used throughout CernoCAMAL. A succession of experiments in simulation and robotic testbeds is carried out to demonstrate improvements and increased efficacy in CernoCAMAL’s overall cognitive performance. A discussion and critical appraisal of the experimental results, together with a summary, a number of potential future research directions, and some closing remarks conclude the thesis

    CernoCAMAL : a probabilistic computational cognitive architecture

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    This thesis presents one possible way to develop a computational cognitive architecture, dubbed CernoCAMAL, that can be used to govern artificial minds probabilistically. The primary aim of the CernoCAMAL research project is to investigate how its predecessor architecture CAMAL can be extended to reason probabilistically about domain model objects through perception, and how the probability formalism can be integrated into its BDI (Belief-Desire-Intention) model to coalesce a number of mechanisms and processes.The motivation and impetus for extending CAMAL and developing CernoCAMAL is the considerable evidence that probabilistic thinking and reasoning is linked to cognitive development and plays a role in cognitive functions, such as decision making and learning. This leads us to believe that a probabilistic reasoning capability is an essential part of human intelligence. Thus, it should be a vital part of any system that attempts to emulate human intelligence computationally.The extensions and augmentations to CAMAL, which are the main contributions of the CernoCAMAL research project, are as follows:- The integration of the EBS (Extended Belief Structure) that associates a probability value with every belief statement, in order to represent the degrees of belief numerically.- The inclusion of the CPR (CernoCAMAL Probabilistic Reasoner) that reasons probabilistically over the goal- and task-oriented perceptual feedback generated by reactive sub-systems.- The compatibility of the probabilistic BDI model with the affect and motivational models and affective and motivational valences used throughout CernoCAMAL.A succession of experiments in simulation and robotic testbeds is carried out to demonstrate improvements and increased efficacy in CernoCAMAL’s overall cognitive performance. A discussion and critical appraisal of the experimental results, together with a summary, a number of potential future research directions, and some closing remarks conclude the thesis

    Getting their acts together: A coordinated systems approach to extended cognition

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    A cognitive system is a set of processes responsible for intelligent behaviour. This thesis is an attempt to answer the question: how can cognitive systems be demarcated; that is, what criterion can be used to decide where to draw the boundary of the system? This question is important because it is one way of couching the hypothesis of extended cognition – is it possible for cognitive systems to transcend the boundary of the brain or body of an organism? Such a criterion can be supplied by what is called in the literature a ‘mark of the cognitive’. The main task of this thesis is to develop a general mark of the cognitive. The starting point is that a system responsible for intelligent behaviour is a coordinated coalition of processes. This account proposes a set of functional conditions for coordination. These conditions can then be used as a sufficient condition for membership of a cognitive system. In certain circumstances, they assert that a given process plays a coordination role in the system and is therefore part of the system. The controversy in the extended cognition debate surrounds positive claims of systemhood concerning ‘external’ processes so a sufficient condition will help settle some of these debates. I argue that a Coordinated Systems Approach like this will help to move the extended cognition debate forward from its current impasse. Moreover, the application of the approach to social systems and stygmergic systems - systems where current processes are coordinated partly by the trace of previous action – promises new directions for research

    Ethological Decision Making with Non-stationary Inputs Using MSPRT Based Mechanisms

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    Cooperative social robots: accompanying, guiding and interacting with people

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    The development of social robots capable of interacting with humans is one of the principal challenges in the field of robotics. More and more, robots are appearing in dynamic environments, like pedestrian walkways, universities, and hospitals; for this reason, their interaction with people must be conducted in a natural, gradual, and cordial manner, given that their function could be aid, or assist people. Therefore, navigation and interaction among humans in these environments are key skills that future generations of robots will require to have. Additionally, robots must also be able to cooperate with each other, if necessary. This dissertation examines these various challenges and describes the development of a set of techniques that allow robots to interact naturally with people in their environments, as they guide or accompany humans in urban zones. In this sense, the robots' movements are inspired by the persons' actions and gestures, determination of appropriate personal space, and the rules of common social convention. The first issue this thesis tackles is the development of an innovative robot-companion approach based on the newly founded Extended Social-Forces Model. We evaluate how people navigate and we formulate a set of virtual social forces to describe robot's behavior in terms of motion. Moreover, we introduce a robot companion analytical metric to effectively evaluate the system. This assessment is based on the notion of "proxemics" and ensures that the robot's navigation is socially acceptable by the person being accompanied, as well as to other pedestrians in the vicinity. Through a user study, we show that people interpret the robot's behavior according to human social norms. In addition, a new framework for guiding people in urban areas with a set of cooperative mobile robots is presented. The proposed approach offers several significant advantages, as compared with those outlined in prior studies. Firstly, it allows a group of people to be guided within both open and closed areas; secondly, it uses several cooperative robots; and thirdly, it includes features that enable the robots to keep people from leaving the crowd group, by approaching them in a friendly and safe manner. At the core of our approach, we propose a "Discrete Time Motion" model, which works to represent human and robot motions, to predict people's movements, so as to plan a route and provide the robots with concrete motion instructions. After, this thesis goes one step forward by developing the "Prediction and Anticipation Model". This model enables us to determine the optimal distribution of robots for preventing people from straying from the formation in specific areas of the map, and thus to facilitate the task of the robots. Furthermore, we locally optimize the work performed by robots and people alike, and thereby yielding a more human-friendly motion. Finally, an autonomous mobile robot capable of interacting to acquire human-assisted learning is introduced. First, we present different robot behaviors to approach a person and successfully engage with him/her. On the basis of this insight, we furnish our robot with a simple visual module for detecting human faces in real-time. We observe that people ascribe different personalities to the robot depending on its different behaviors. Once contact is initiated, people are given the opportunity to assist the robot to improve its visual skills. After this assisted learning stage, the robot is able to detect people by using the enhanced visual methods. Both contributions are extensively and rigorously tested in real environments. As a whole, this thesis demonstrates the need for robots that are able to operate acceptably around people; to behave in accordance with social norms while accompanying and guiding them. Furthermore, this work shows that cooperation amongst a group of robots optimizes the performance of the robots and people as well.El desenvolupament de robots socials capaços d'interactuar amb els Ă©ssers humans Ă©s un dels principals reptes en el camp de la robĂČtica. Actualment, els robots comencen a aparĂšixer en entorns dinĂ mics, com zones de vianants, universitats o hospitals; per aquest motiu, aquesta interacciĂł ha de realitzar-se de manera natural, progressiva i cordial, ja que la seva utilitzaciĂł pot ser col.laboraciĂł, assistĂšncia o ajuda a les persones. Per tant, la navegaciĂł i la interacciĂł amb els humans, en aquests entorns, sĂłn habilitats importants que les futures generacions de robots han de posseir, a mĂ©s a mĂ©s, els robots han de ser aptes de cooperar entre ells si fos requerit. El present treball estudia aquests reptes plantejats. S’han desenvolupat un conjunt de tĂšcniques que permeten als robots interectuar de manera natural amb les persones i el seu entorn, mentre que guien o acompanyen als humans en zones urbanes. En aquest sentit, el moviment dels robots s’inspira en la manera com es mouen els humans en les convenvions socials, aixĂ­ com l’espai personal.El primer punt que aquesta tesi comprĂšn Ă©s el desenvolupament d’un nou mĂštode per a "robots-acompanyants" basat en el nou model estĂšs de forces socials. S’ha evaluat com es mouen les persones i s’han formulat un conjunt de forces socials virtuals que descriuren el comportament del robot en termes de moviments. Aquesta evaluaciĂł es basa en el concepte de “proxemics” i assegura que la navegaciĂł del robot estĂ  socialment acceptada per la persona que estĂ  sent acompanyada i per la gent que es troba a l’entorn. Per mitjĂ  d’un estudi social, mostrem que els humans interpreten el comportament del robot d’acord amb les normes socials. AixĂ­ mateix, un nou sistema per a guiar a persones en zones urbanes amb un conjunt de robots mĂČbils que cooperen Ă©s presentat. El model proposat ofereix diferents avantatges comparat amb treballs anteriors. Primer, es permet a un grup de persones ser guiades en entorns oberts o amb alta densitat d’obstacles; segon, s’utilitzen diferents robots que cooperen; tercer, els robots sĂłn capaços de reincorporar a la formaciĂł les persones que s’han allunyat del grup anteriorment de manera segura. La base del nostre enfocament es basa en el nou model anomenat “Discrete Time Motion”, el qual representa els movimients dels humans i els robots, prediu el comportament de les persones, i planeja i proporciona una ruta als robots.Posteriorment, aquesta tesi va un pas mĂ©s enllĂ  amb el desenvolupament del model “Prediction and Anticipation Model”. Aquest model ens permet determinar la distribuciĂł ĂČptima de robots per a prevenir que les persones s’allunyin del grup en zones especíıfiques del mapa, i per tant facilitar la tasca dels robots. A mĂ©s, s’optimitza localment el treball realitzat pels robots i les persones, produint d’aquesta manera un moviment mĂ©s amigable. Finalment, s’introdueix un robot autĂČnom mĂČbil capaç d’interactuar amb les persones per realitzar un aprenentatge assistit. Incialment, es presenten diferents comportaments del robot per apropar-se a una persona i crear un víıncle amb ell/ella. Basant-nos en aquesta idea, un mĂČdul visual per a la detecciĂł de cares humanes en temps real va ser proporcionat al robot. Hem observat que les persones atribueixen diferents personalitats al robot en funciĂł dels seus diferents comportaments. Una vegada que el contacte va ser iniciat es va donar l’oportunitat als voluntaris d’ajudar al robot per a millorar les seves habilitats visuals. DesprĂ©s d’aquesta etapa d’aprenentatge assistit, el robot va ser capaç d’identificar a les persones mitjançant l'Ășs de mĂštodes visuals.En resum, aquesta tesi presenta i demostra la necessitat de robots que siguin capaços d’operar de forma acceptable amb la gent i que es comportin d’acord amb les normes socials mentres acompanyen o guien a persones. Per altra banda, aquest treball mostra que la coperaciĂł entre un grup de robots pot optimitzar el rendiment tant dels robots com dels humans

    Deployment and navigation of aerial drones for sensing and interacting applications

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    Existing research recognises the critical role played by Unmanned Aerial Vehicles (UAVs) (also referred to as drones) to numerous civilian applications. Typical drone applications include surveillance, wireless communication, agriculture, among many others. One of the biggest challenges is to determine the deployment and navigation of the drones to benefit the most for different applications. Many research questions have been raised about this topic. For example, drone-enabled wildlife monitoring has received much attention in recent years. Unfortunately, this approach results in significant disturbance to different species of wild animals. Moreover, with the capability of rapidly moving communication supply towards demand when required, the drone equipped with a base station, i.e., drone-cell, is becoming a promising solution for providing cellular networks to victims and rescue teams in disaster-affected areas. However, few studies have investigated the optimal deployments of multiple drone-cells with limited backhaul communication distances. In addition, the use of autonomous drones as flying interactors for many real-life applications has not been sufficiently discussed. With superior maneuverability, drone-enabled autonomous aerial interacting can potentially be used on shark attack prevention and animal herding. Nevertheless, previous studies of autonomous drones have not dealt with such applications in much detail. This thesis explores the solutions to all the mentioned research questions, with a particular focus on the deployment and navigation of the drones. First, we provide one of the first investigations into reducing the negative impacts of wildlife monitoring drones by navigation control. Second, we study the optimal placement of a group of drone-cells with limited backhaul communication ranges, aims to maximise the number of served users. Third, we propose a novel method named ‘drone shark shield’, which uses communicating autonomous drones to intervene and prevent shark attacks for protecting swimmers and surfers. Lastly, we introduce one of the first autonomous drone herding systems for mustering a large number of farm animals efficiently. Simulations have been conducted to verify the effectiveness of the proposed approaches. We believe that our findings in this thesis shed new light on the fundamental benefits of autonomous civilian drones

    An Approach Based on Particle Swarm Optimization for Inspection of Spacecraft Hulls by a Swarm of Miniaturized Robots

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    The remoteness and hazards that are inherent to the operating environments of space infrastructures promote their need for automated robotic inspection. In particular, micrometeoroid and orbital debris impact and structural fatigue are common sources of damage to spacecraft hulls. Vibration sensing has been used to detect structural damage in spacecraft hulls as well as in structural health monitoring practices in industry by deploying static sensors. In this paper, we propose using a swarm of miniaturized vibration-sensing mobile robots realizing a network of mobile sensors. We present a distributed inspection algorithm based on the bio-inspired particle swarm optimization and evolutionary algorithm niching techniques to deliver the task of enumeration and localization of an a priori unknown number of vibration sources on a simplified 2.5D spacecraft surface. Our algorithm is deployed on a swarm of simulated cm-scale wheeled robots. These are guided in their inspection task by sensing vibrations arising from failure points on the surface which are detected by on-board accelerometers. We study three performance metrics: (1) proximity of the localized sources to the ground truth locations, (2) time to localize each source, and (3) time to finish the inspection task given a 75% inspection coverage threshold. We find that our swarm is able to successfully localize the present so

    Task Allocation in Foraging Robot Swarms:The Role of Information Sharing

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    Autonomous task allocation is a desirable feature of robot swarms that collect and deliver items in scenarios where congestion, caused by accumulated items or robots, can temporarily interfere with swarm behaviour. In such settings, self-regulation of workforce can prevent unnecessary energy consumption. We explore two types of self-regulation: non-social, where robots become idle upon experiencing congestion, and social, where robots broadcast information about congestion to their team mates in order to socially inhibit foraging. We show that while both types of self-regulation can lead to improved energy efficiency and increase the amount of resource collected, the speed with which information about congestion flows through a swarm affects the scalability of these algorithms
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