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A fundamental prerequisite to achieve a successful human-robot cooperation is human safety, which becomes even more crucial when multiple robots are involved in the cooperative task. A general solution for addressing safety in human-multi-robot scenarios is proposed in this paper. Human safety is assessed by a safety field which accounts for the multi-robot system as a whole. The assessment of human safety is exploited within an optimization protocol where the robots’ cooperative task trajectory is scaled whenever required, while exploiting the system redundancy. Control Barrier Functions (CBFs) are adopted to set up the optimization problem and kinematic and dynamic constraints are taken into consideration. Finally, simulations on a realistic setup composed of three industrial mobile manipulators show the effectiveness of the proposed solution.

In this paper, a general framework to control in a distributed way a system composed by multiple robots is proposed. Each robot is characterized by a discrete-time linear dynamics, and the whole system is controlled via a linear static feedback law with a feed-forward term. Usually, this form of the global control input requires a central unit or an all-to-all communication for computing the local control input of each robot. To counteract the lack of a central unit, each robot estimates, via a local observer, the overall state of the team, and such an estimate is used to compute its local control input as in the case a central unit was present. Two simulations case studies are provided in the framework of multi-robot optimal control and formation control.