In new research, researchers establish the likelihood of blockchain technology, known from cryptocurrencies like Ethereum and Bitcoin, to safeguard the coordination of robot swarms. Experiments performed with both simulated and real robots disclose how blockchain technology facilitates a robot swarm to neutralize dangerous robots with no human intervention, thus facilitating the employment of independent and safe robot swarms.
Robot swarms, multi-robot systems, comprise multiple robots that work together to conduct a task. They do not require a central control unit, but the combined behavior of the swarm is instead a consequence of local interactions between robots.
Due to this decentralization, robot swarms can function independently of external infrastructure, like the Internet. Specifically, this makes them fit for applications in a wide variety of varied environments, like underwater, underground, in space, and at sea.
Despite current swarm robotics applications are uniquely established in research environments, specialists expect that in the non-distant future, robot swarms will guide in the daily life.
Robot swarms may conduct environmental tracking, infrastructure inspection, underwater exploration, and waste management, making considerable contributions to the shift into a fossil-free future with high quality and low pollution of life. In a few activities, robot swarms will also outdo humans, resulting in higher-quality outcomes while guaranteeing safety.
However, once robot swarms are employed in real-time, it is possible that a few robots in a swarm will break down (for instance, owing to extreme weather conditions) or might also get hacked.
Those robots will not act as planned and are known as “Byzantine” robots. The new study has revealed that the movements of a tiny minority of those Byzantine robots in a swarm can—identical to a virus—disperse in the swarm and thereby break down the complete system. Even though security issues are critical for the real-time employment of robot swarms, security studies in swarm robotics are still lagging.
Byzantine users—like hackers- in Internet networks—have been efficiently avoided from influencing data using blockchain technology. The technology underlying Bitcoin is blockchain technology: it facilitates users to approve of “who owns what” without needing a trusted third party, for example, a bank.
Initially, blockchain technology was just considered for the exchange units of a digital currency, like Bitcoin. However, after some years of Bitcoin’s release, Ethereum framework introduces blockchain-based smart contracts: such smart contracts are programming code achieved in a blockchain network. As none can influence or break this code, smart contracts allow “code is law”: contracts are executed automatically and do not require a trusted third party, like a court, to be applied.
Until now, it was unclear if smart contracts and blockchain could influence large robot swarms. To answer this open question, researchers presented an all-inclusive study with both simulated and real robots in a collective-sensing scenario: the robot swarm's objective is to estimate an environmental characteristic. To execute that, the robots must sample the environment and approve the feature value.
In the experiments, every robot is a member of a blockchain network maintained by the robots. The robots send their estimates of environmental features to a smart contract shared by all the robots in the swarm.
Such estimates are collected by the smart contract that employs them to produce the requested estimate of the environmental character. In this smart contract, researchers applied mechanisms that guarantee that good (non-Byzantine) robots are rewarded for offering valuable data, while harmful Byzantine robots are penalized. The consequent robot economy prevents the Byzantine robots from participating in the swarm activities and manipulating the swarm behavior.
Including a blockchain in a robot swarm improves the computational requirements of robots, like RAM, CPU, and disk space usage. Indeed, if running blockchain software on real robot swarms was feasible or not is an open question. The experiments have established that this is feasible as the computational needs are controllable: the extra CPU, RAM, and disk space usage slightly affect the robot's performance.
This efficient combination of blockchain technology with robot swarms opens a door for a broad collection of safe robotic applications. For favorable future developments, they released their software frameworks as open-source.
Strobel, V., et al. (2023) Robot swarms neutralize harmful Byzantine robots using a blockchain-based token economy. Science Robotics. doi.org/10.1126/scirobotics.abm4636.