Analysing the suitability of blockchain consensus algorithms in swarm robotics

Swarm robotics integrates robotics with swarm intelligence. Consensus achievement is one of the major behaviours of swarm robotics. Strategies that solve the consensus-achievement problem have been shown to be vulnerable to Byzantine robots. Blockchain-based solutions have been shown to improve Byzantine fault tolerance. However, these solutions suffer from poor performance, excessive resource consumption, and vulnerability to the 51% attack due to the use of the proof-of-work consensus algorithm. This study surveys existing blockchain consensus algorithms and their suitability to swarm robotics. Consequently, a taxonomy is introduced consisting of three categories, namely proof of resource, proof of authority, and Byzantine agreement. The proof-of-resource algorithms are vulnerable to the 51% attack and consume excess resources. Proof of authority algorithms creates permissioned blockchains, which contravenes the principles of swarm robotics. Byzantine agreement algorithms introduce centralisation. Consequently, the need for a new consensus algorithm to be used in swarm robotics is postulated.