Collective motion in non-reciprocal swarms

This paper studies a non-reciprocal swarm model that consists of a group of mobile autonomous agents with an attraction-repulsion function governing the interaction of the agents. The function is chosen to have infinitely large values of repulsion for vanishing distance between two agents so as to avoid occurrence of collision. It is shown analytically that under the detailed balance condition in coupling weights, all the agents will aggregate and eventually form a cohesive cluster of finite size around the weighted center of the swarm in a finite time. Moreover, the swarm system is completely stable, namely, the motion of all agents converge to the set of equilibrium points. For the general case of non-reciprocal swarms without the detailed balance condition, numerical simulations show that more complex self-organized oscillations can emerge in the swarms. The effect of noise on collective dynamics of the swarm is also examined with a white Gaussian noise model.

FlockSeer:A portable stereo vision observer for bird flocking

Bird flocking is a paradigmatic case of self‐organised collective behaviours in biology.Stereo camera systems are employed to observe flocks of starlings,jackdaws,and chimney swifts,mainly on a spot‐fixed basis.A portable non‐fixed stereo vision‐based flocking observation system,namely FlockSeer,is developed by the authors for observing more species of bird flocks within field scenarios.The portable flocking observer,FlockSeer,responds to the challenges in extrinsic calibration,camera synchronisation and field movability compared to existing spot‐fixed observing systems.A measurement and sensor fusion approach is utilised for rapid calibration,and a light‐based synchronisation approach is used to simplify hardware configuration.FlockSeer has been implemented and tested across six cities in three provinces and has accomplished diverse flock‐tracking tasks,accumulating behavioural data of four species,including egrets,with up to 300 resolvable trajectories.The authors reconstructed the trajectories of a flock of egrets under disturbed conditions to verify the practicality and reliability.In addition,we analysed the accuracy of identifying nearest neighbours,and then examined the similarity between the trajectories and the Couzin model.Experimental results demonstrate that the developed flocking observing system is highly portable,more convenient and swift to deploy in wetland‐like or coast‐like fields.Its observation process is reliable and practical and can effectively support the study of understanding and modelling of bird flocking behaviours.

Triangular lattice formation in robot swarms with minimal local sensing

The problem of triangular lattice formation in robot swarms has been investigated extensively in the literature,but the existing algorithms can hardly keep comparative performance from swarm simulation to real multi‐robot scenarios,due to the limited computation power or the restricted field of view(FOV)of robot sensors.Eventually,a distributed solution for triangular lattice formation in robot swarms with minimal sensing and computation is proposed and developed in this study.Each robot is equipped with a sensor with a limited FOV providing only a ternary digit of information about its neighbouring environment.At each time step,the motion command is directly determined by using only the ternary sensing result.The circular motions with a certain level of randomness lead the robot swarms to stable triangular lattice formation with high quality and robustness.Extensive numerical simulations and multi‐robot experiments are conducted.The results have demonstrated and validated the efficiency of the proposed approach.The minimised sensing and computation requirements pave the way for massive deployment at a low cost and implementation within swarms of miniature robots.