Coordination of multi-robot systems to improve communication and achieve flocking is the topic of this thesis. Methods are proposed for mobile autonomous robots to follow trajectories in a way that improves communications with a base station. Further, a decentralized algorithm is presented that yields flocking with obstacle avoidance. The communication-aware trajectory tracking is adapted to radio communication in indoor environments. Our experimental data show that the effect of multipath fading, well-known in the radio communication literature, causes significant variations in the signal strength between a mobile robot and a base station. A contribution of this thesis is to formulate a tradeoff between tracking a reference trajectory and maintaining communication, first for a stationary reference position and then for a general trajectory. For the general case, the robot and an onboard communication buffer are modelled as a hybrid system, switching between standing still to communicate at positions with good signal strength and driving to catch up with the reference. This problem is solved using relaxed dynamic programming. For the case of a stationary reference position, experimental validation shows that loss of communication is avoided and that the method yields a gain in signal strength. The algorithm for flocking is based on Voronoi partitions. They can be approximated using only local information and allow the agents to avoid collisions. Our contribution is to add obstacle avoidance and movement towards a goal by using a navigation function - a scalar potential field with exactly one local minimum at the goal. To bound the inter-agent distances and thus avoid flock dispersion, any agent on the boundary of the flock uses a mirroring mechanism to create virtual neighbors that drive it inwards. We can prove collision safety and bounded group dispersion, and simulations show reliable goal convergence even in the presence of non-convex obstacles. A version of the algorithm with lower computational complexity ...


    Access

    Download


    Export, share and cite



    Title :

    On Communication and Flocking in Multi-Robot Systems


    Contributors:

    Publication date :

    2007-01-01


    Type of media :

    Theses


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :

    DDC:    629



    Flocking Control of Multi-Quadrotor System of Systems

    Jian, Di / Haibo, Ji / Yeqiu, Liu et al. | IEEE | 2018


    Anisotropic Flocking Control of Distributed Multi-Agent Systems using Fluid Abstraction

    Silic, Matthew B. / Song, Zhuoyuan / Mohseni, Kamran | AIAA | 2018


    HEAD-UP DISPLAY UNIT FOR VEHICLE WITH FLOCKING AND METHODS FOR FLOCKING

    FONG CHING / TENKA FRANKY | European Patent Office | 2022

    Free access

    Selective model-predictive control for flocking systems

    Albi, Giacomo / Lorenzo, Pareschi | BASE | 2018

    Free access

    Flocking-Enhanced social contagion

    Levis, D. / Diaz-Guilera, A / Pagonabarraga, I. et al. | BASE | 2020

    Free access