The Coordination Approach For Heterogeneous Multi-robot Teams

With the developing of the technologies, the ability of robot is significantly improved. The robots therefore become more and more common in many fields, doing dirty, dull or dangerous works, ranging from mapping and exploration to robot soccer.Researches generally agree that multi-robot systems (MRS) with inherently distributed character may behave more robustly and effectively and accomplish coordinated tasks that are not possible for single robot systems. However, suitable strategies are required to organize and control these systems to alleviate the inherent complex, dynamic, volatile, and coupling influences. This dissertation makes a number of contributions in response to the need for effective coordination approaches in heterogeneous multi-robot teams.1) We address the need for a survey of the relevant literature by providing an introduction to the multi-robot coordination, a review and analysis of the state of the art in the field, and a discussion of remaining research challenges. The main focus of the survey include multi-robot systems, task allocation, network robot systems, evolutionary development robotics, development environments and middleware for robots, and their military applications.2) We proposed the constraint based approach (CoBA) for the cooperation among a team of heterogeneous robots in the complex environment with temporal constraints and network constraints. First we put forward a dynamic acquaintance network to facilitate the maintenance of inter-robot relationship. Hence the degree of acquaintanceship can be used in the indirect bid of task. Second, in order to model the complex tasks, we introduce the AND/OR task tree with temporal constraints and corresponding evaluation method. Additionally, an auction clearing routine, which supports the AND/OR task tree with temporal constraints and direct/indirect task auction is proposed to enable effective multi-robot task allocation in spite of various constraints. The solution was validated in both simulation and physical environments by a series of experiments in disaster response domains.3) Evolutionary Robotics (ER) is a methodology that uses evolutionary computation to develop controllers for autonomous robots. The existing works focus on single robot system or physically homogenous multi-robot teams while physical heterogeneousness is more common in the real world. Hence, it is instructive to examine whether the cooperative behaviors can be synthesized using artificial evolution for a team of physically heterogeneous robots. Moreover, an important contribution of this dissertation is to answer the question:whether robots with distinct capabilities can synthesize their control strategies to accommodate their own capabilities without any human interventions? This dissertation offers an empirical analysis of the collaboration mechanisms and presents some basic advice about how to choose appropriate evolution methods. Simulated experiments, using a team of E-puck robots, show that evolution can discover effective controllers for robots with distinct capabilities.4) Network robot system (NRS) is a new concept that integrates physical autonomous robots, environmental sensors and human-robot interactions through network-based cooperation. We aim to provide a ubiquitous and cooperative service framework for NRS. We first present foundational concepts of semantic map and service definition for the framework. Then, in order to generate feasible service configurations to fulfill tasks, we propose service configuration and reconfiguration algorithms, which dynamically search the appropriate service configurations for different tasks. Additionally, we put forward a service reasoning and enabling process to tackle the service unavailable problems. A cost evaluation function for service configuration is also proposed to facilitate the selection of suitable configurations. We tested and evaluated the framework in both simulation system and physical environment.5) A multiple UGV system is constructed under the application of special tasks. This system implements unmanned mobility, reconnaissance and surveillance, tactical communications, formation control, path planning and obstacle avoidance, and mission planning and monitoring. Specially, an objective oriented task evaluation method is proposed for quick response to different types of tasks, and a method with real-time correction of the credibility of the prior information is suggested for multi-sensor target recognition. The cooperative ability of the system was validated in physical environment by a series of experiments.