Connectivity maintenance is an essential aspect to consider while controlling a multi-robot system. In general, a multi-robot system should be connected to obtain a certain common objective. Connectivity must be kept regardless of the control strategy or the objective of the multi-robot system. Two main methods exist for connectivity maintenance: keep the initial connections (local connectivity) or allow modifications to the initial connections, but always keeping the overall system connected (global connectivity). In this paper we present a method that allows, at the same time, to maintain global connectivity and to implement the desired control strategy (e.g., consensus, formation control, coverage), all in an optimized fashion. For this purpose, we defined and implemented a Control Barrier Function that can incorporate constraints and objectives. We provide a mathematical proof of the method, and we demonstrate its versatility with simulations of different applications.
University of Modena and Reggio Emilia（摩德纳-雷焦艾米利亚大学）；École Polytechnique de Montréal（蒙特利尔理工学院）
Connectivity maintenance is crucial for the real world deployment of multi-robot systems, as it ultimately allows the robots to communicate, coordinate and perform tasks in a collaborative way. A connectivity maintenance controller must keep the multi-robot system connected independently from the system's mission and in the presence of undesired real world effects such as communication delays, model errors, and computational time delays, among others. In this paper we present the implementation, on a real robotic setup, of a connectivity maintenance control strategy based on Control Barrier Fu…
University of Pennsylvania（宾夕法尼亚大学）；Drexel University（德雷塞尔大学）
We study the problem that requires a team of robots to perform joint localization and target tracking task while ensuring team connectivity and collision avoidance. The problem can be formalized as a nonlinear, non-convex optimization program, which is typically hard to solve. To this end, we design a two-staged approach that utilizes a greedy algorithm to optimize the joint localization and target tracking performance and applies control barrier functions to ensure safety constraints, i.e., maintaining connectivity of the robot team and preventing inter-robot collisions. Simulated Gazebo expe…
Control Strategies for Pursuit-Evasion Under Occlusion Using Visibility and Safety Barrier Functions
University of California San Diego（加利福尼亚大学圣迭戈分校）；General Dynamics Mission Systems（通用动力任务系统公司）；Honda R&D Co. Ltd.（本田研发有限公司）；University of Michigan（密歇根大学）
Robot missions typically involve a number of desired objectives, such as avoiding collisions, staying connected to other robots, gathering information using sensors and returning to the charging station before the battery runs out. Some of these objectives need to be taken into account at the same time, such as avoiding collisions and staying connected, while others are focused upon during different parts of the executions, such as returning to the charging station and connectivity maintenance. In this paper, we show how Control Barrier Functions(CBFs) and Behavior Trees(BTs) can be combined i…
Decentralized Control of Uncertain Multi-Agent Systems with Connectivity Maintenance and Collision Avoidance
ACCESS Linnaeus Center, School of Electrical Engineering, KTH Royal Institute of Technology（ACCESS林奈中心，电气工程学院，皇家理工学院）；KTH Center for Autonomous Systems（KTH自主系统中心）
Position and Orientation Based Formation Control of Multiple Rigid Bodies with Collision Avoidance and Connectivity Maintenance
ACCESS Linnaeus Center, School of Electrical Engineering, KTH Royal Institute of Technology（ACCESS林奈斯中心，电气工程学院，KTH皇家理工学院）；KTH Center for Autonomous Systems（KTH自主系统中心）
Real-Time Reconfiguration and Connectivity Maintenance for AUVs Network Under External Disturbances using Distributed Nonlinear Model Predictive Control
A teleoperated swarm must follow the unpredictable commands of its human operator while remaining connected. When the swarm communications are limited by distance and affected by delays, both the user input and the transmission delays endanger the connectivity of the swarm. This paper presents a constructive control strategy that overcomes both threats. The strategy modulates the intra-swarm couplings and the damping injected to each slave in the swarm based on a customized potential. Lyapunov-based set invariance analysis proves that the proposed explicit gain updating law limits the impact o…
Cooperative Decentralized Multi-agent Control under Local LTL Tasks and Connectivity Constraints
ACCESS Linnaeus Center, School of Electrical Engineering, KTH Royal Institute of Technology（ACCESS林奈中心，电气工程学院，皇家理工学院）；KTH Centre for Autonomous Systems（KTH自主系统中心）
