Blockchain-based swarm robotics system (Part 42)

Welcome to the 42nd part of the 100-part series on Blockchain.

Many upcoming streams are changing the technology landscape, and Robotics is one of them. Robotics has even been referred to as the Next Technological Revolution by many industry experts. Robotics is going to be a multi-billion global industry and is going to have a tremendous impact on many other industries in the coming years.

Swarm robotics

Whenever we think of robots, we are hardwired to imagine a single, sophisticated robot with jerking movements and a thick voice that we have experienced in various sci-fi movies. Not necessarily; there is a branch of robotics known as “Swarm Robotics” that involves many simple robots. The field of Swarm robotics is inspired by nature. Creatures like insects, fishes, birds, and bees exhibit swarm behavior. These swarms range from a few individuals living in their small natural habitats to millions of individuals living in highly organized colonies. The individuals in these swarms show very poor abilities, but when combined with the intelligence of the whole group, these swarms exhibit great flexibility and robustness in completing complex activities such as path planning, task allocation, and various other complex collective behaviors. Researchers have established the fact that this intelligent collective behavior emerges from local communication and information transmission among these individuals.

Swarm robotics came into being based on this very concept of the collective intelligence of individuals. Swarm robotics is a branch of robotics in which many simple robots are coordinated in a distributed and decentralized way. It operates on the principle of local communication and information transmission between these simple robots. These large numbers of simple robots can perform complex tasks in a much more efficient manner than a single robot. A key advantage of these robotic swarms is their scalability and robustness to failure. And both of these qualities originate from their simple and distributed nature of coordination.

Swarm of robots

The number of use cases for robotic swarms is increasing with the decreasing cost of these robotics platforms. Some of the applications include targeted material delivery, where groups of small robots carry big and heavy objects; precision farming, where they support farmers in their agricultural activities; entertainment industry, where groups of these swarm robots come together to form interactive displays; in the nuclear, chemical and biological attack detection, battlefield surveillance, and space exploration, etc.

Challenges in implementing robotic swarms

However, there are still many grey areas in implementing these robotic swarms, which are proving to be a challenge in their widespread adoption. Some of these challenges include a lack of safety measures, decentralized control, and lack of security protocols for these robotic systems.

Blockchain- The Solution

Enter Blockchain. Blockchain can provide a solution to the challenges faced by these robotic swarms. Implementing Blockchain with these swarm robotic systems can lead to wider adoption of these systems across various industries. Blockchain can make them more secure, reliable, autonomous, and profitable, leading to a mass-scale acceptance of these robotic swarms.

In such a system, robots will act as nodes, and the information flow between them will be recorded as transactions on the Blockchain.

Now let’s have an in-depth look at the challenges faced by swarm robotic systems and how does the implementation of Blockchain can help to tackle them.

Blockchain in the transmission of messages

Security is the first and foremost challenge for deploying these systems in large-scale commercial projects. This is very crucial for these systems as the inclusion of any defective or malicious swarm member can compromise the security of the swarm or can put a risk to the completion of the intended goal by the swarm.

Security for robotic swarms fundamentally includes data integrity, data confidentiality, data origin authentication, and entity authentication.

Blockchain technology can be a solution to these security challenges faced by swarm robotic systems as it not only provides a private and reliable peer-to-peer communication network for swarm agents but also has provisions to overcome potential threats, vulnerabilities, and attacks.

Blockchain, with its robust encryption mechanism, including a public key and digital signature cryptography, can provide a secure way of transactions happening through unsafe and shared communication channels. Further, this technology can also prove the identity of a specific agent trying to communicate with other agents. Thus, bringing trust and transparency to the system. The implementation includes generating a pair of private and public keys for each swarm agent. The public key, as the name suggests, will be publicly available in the Blockchain network and provides the address to an agent’s main accessible information.

For the sake of simplicity, a public key can be treated as a special account number for the agent. Conversely, a private key can be compared to a password in a traditional system and holds an agent’s covert information. Public keys are used for validating the identity of an agent, and private keys are used for executing the transactions.

Refer to Part 6 for detailed information on Cryptography and digital signature.

With public key cryptography, robots can share their public keys with other robots who want to communicate with them. With the availability of these public keys, any robot can send information to any specific robot or robots in the network by encrypting the information with its public key. It ensures that the robot possessing the matching private key can access the information (Fig 1a). Since public keys don’t have the ability to decrypt messages, the security doesn’t get compromised even if it falls into the wrong hands. Besides, this mechanism also prevents information decryption by third-party robots even if they share the same communication channel.

Fig 1: Encrypting information with (a) receiver robot’s public key and (b) sender robot’s private key

Additionally, under digital signature cryptography, these robots can use their own private key to encrypt their messages. In this cryptography, other robots can decrypt the information or the message using the public key of the sender robot (Fig 1b). This public key is available to everyone on the Blockchain network. Therefore, the message won’t be a secret per se, but it can be used to prove the authorship of that message or information. Because the message is encrypted by a particular robot’s private key and therefore it can’t be sent by someone else, hence establishing authorship of the message.

Both of these cryptographic techniques can be used to tackle the security loopholes prevalent in Swarm Robotic Systems. On the one hand, public key cryptography ensures that only a specific robot having a specific address can access the content of a message encapsulated in a transaction based on Blockchain technology. On the other hand, digital signature cryptography ensures data origin authentication and entity authentication between robots or third-party agents.

The practical applications of these Blockchain-secured robotic swarms include the military, where trustworthy and reliable systems are very much required, and medical projects where a team of robots helps in the transportation of medicines and medical records of the patients as in these cases, data confidentiality is the most crucial factor.

Blockchain in distributed decision making

The individual agents or robots in the swarm are required to reach a global agreement regarding the goal. For example, the path to be taken, obstacles to be avoided, shape to be formed, etc. Therefore, for these swarms to work efficiently, distributed decision-making protocols are required to ensure guaranteed convergence towards a common outcome. Currently, this is still an open problem, and there is no foolproof distributed decision-making protocol that can handle a large number of swarm agents efficiently.

Blockchain is a perfect match for this requirement of robotic swarms. It has the required capability to ensure that the participating agents in a decentralized network always reach a global agreement regarding the end goal. For example, the Blockchain has the provision of distributed voting systems that can be used by these swarm robotic systems whenever they have to reach a global agreement.

Let’s understand how this distributed voting system works for these swarms:

Whenever a situation arises, when one agent of the swarm needs to get agreement from other agents of the swarm, a special transaction can be issued on the Blockchain network. This transaction will create separate addresses for the possible options that the swarm has to vote on.

For instance, in the given scenario, these agents need to decide which path to take out of the 3 paths as visible on the sign board. In this case, the 3 possible options are — Path 1, Path 2, and Path 3, respectively. Now one of the agents will create 3 different addresses for these 3 options. The swarm members can then vote as per their understanding of the situation on these addresses.

As this information is publicly available on the network, every robot can monitor the results of the voting process and act accordingly. In this case, as all of them can see that Route 2, got the maximum votes, the robot swarm will accept it as the group decision, and they all will take Route 2.

Hence Blockchain provides a very good protocol for distributed decision-making where agreements can be obtained swiftly and in a secure and auditable way.

Blockchain and service robot systems

There are various robotic swarms that have been programmed to find various natural resources, and objects. A very critical part of their activity is to establish the ownership and exploitation rights on a found object or resource on behalf of their owner or operator. For instance, a special robotic swarm programmed to do cave explorations finds a hidden treasure in one of the caves. The swarm issues a discovery document on the Blockchain claiming the ownership of that treasure on behalf of their owner. The transaction may include the discovered objects, relevant reports, coordinates of the place of discovery, and images if feasible. A hash is generated along with the time stamp for this document. This, then, gets included as a transaction on the Blockchain as proof of discovery.

In this way, Blockchain can provide the required framework for ensuring that robotic swarms operate under a specific legal regulation as they become mainstream and gets integrated into human society.

Thus, it can be said that Blockchain technology could be a game changer for the mass adoption of Swarm Robotic Systems. The amalgamation of these 2 upcoming technologies can open doors for new technological advancements and even new business models that we can’t even imagine today.

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