Motion Control & Drives

Thousands of robots swarm together collaboratively

January 2015 Motion Control & Drives

Each low-cost, three-legged robot moves around with the help of two motors that vibrate at different frequencies, causing it to move across a surface on its rigid legs. It communicates with its neighbours, measuring their proximity through infrared transmitters and receivers. After being programmed to form a set shape such as the letter K or a starfish, each one in turn navigates its way to a final position using primitive behaviours – following the edge of a group, tracking a distance from the origin or maintaining a sense of relative location. If a traffic jam forms, nearby robots sense it and co-operate to fix the problem.

Credit: Harvard SEAS.
Credit: Harvard SEAS.

“Each robot is identical and is controlled by exactly the same program,” explains Dr Michael Rubenstein from Harvard University School of Engineering & Applied Sciences. “The only thing they have to go on to make decisions is what their neighbours are doing.” The robots are much simpler than many conventional robots, for example individuals may have trouble moving in a straight line; but at full scale the smart algorithm controlling them overcomes individual limitations and the robots can complete a human-specified task – like assembling into a particular shape.

Infrared control

Although the Kilobots can communicate with their neighbours, they have no sense of a broader environment. Four robots mark out the origin of a coordinate system while the remaining robots receive a 2D image of the shape. The initial set of instructions is beamed to the robots via infrared, after which they work autonomously, requiring no further human intervention. Starting with a random selection, if they are in a position to move they motor slowly around, flashing their infrared lights to broadcast information to other Kilobots nearby. They then assemble into the specified shape.

Inspiration from nature

The self-organising behaviour was inspired by the cooperative activities of insects like army ants. The Harvard team aims to provide a physical model for advancing the understanding of collective behaviour, creating artificial swarms with the capabilities of natural ones. The Kilobot demonstrates how simple machines performing simple behaviours can create complexity in a group and that robots can be programmed to perform useful functions by coordinating interactions among many individuals. “The beauty of biological systems is that they are elegantly simple yet in large numbers accomplish the seemingly impossible. At some level you no longer even see the individuals, you just see the collective as an entity in itself,” says research leader Radhika Nagpal, professor of computer science at the Harvard School of Engineering and Applied Sciences.

Practical testing of advanced algorithms

Although there is a large amount of research on algorithms and control methods for groups of decentralised, cooperating robots, they are generally validated by simulation only. The Kilobot goes well beyond the state-of-the-art in robotics by allowing the practical testing of advanced algorithms on a large scale through the use of cheap materials and simple programming. “Performing complex behaviours with as little hardware as possible to keep costs down encompasses the spirit of Kilobots,” says Rubenstein.

An important milestone

The technology is being heralded as an important milestone in the development of collective artificial intelligence. “Increasingly we’re going to see large numbers of robots working together to solve problems,” adds Nagpal. The researchers believe that robot swarms might one day tunnel through rubble to find survivors, remove contaminants from the environment, assist dwindling bee populations in pollinating crops and self-assemble to form support structures in collapsed buildings. Success in getting so many robots to self-organise could be a significant milestone in the development of nanotechnology and a collective artificial intelligence, according to the researchers. The next stage is to refine the intelligence and develop smaller robots capable of the same tasks, eventually aiming for the nano scale.

For more information visit

Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

V-belts designed for food applications
September 2021, Bearing Man Group t/a BMG , Motion Control & Drives
BMG supplies a wide range of power transmission components, designed to enhance efficiency and safety in the food and beverage sector.

Control automation excellence
September 2021, SEW-Eurodrive , Motion Control & Drives
Movi-C from SEW-EURODRIVE is a unique automation control system that sets a new benchmark in control automation, embracing Industry 4.0 technology.

Efficient agriculture systems from BMG
Technews Industry Guide: Sustainable Manufacturing 2021, Bearing Man Group t/a BMG , Motion Control & Drives
BMG’s Boer Slim/Smart-Farming agricultural team works closely with farmers throughout southern Africa, assisting them with the selection, installation and operation of new electromechanical systems. These ...

Inertial spin filters save energy
Technews Industry Guide: Sustainable Manufacturing 2021 , Motion Control & Drives
RTS Africa’s inertial spin filters provide an effective, maintenance-free solution to dust problems in MCC rooms, transformer rooms, control rooms and the like.

Drives for the chemical sector
July 2021, Bearing Man Group t/a BMG , Motion Control & Drives
BMG’s range of Danfoss electronic, mechanical and intelligent mechatronic devices are designed to optimise automation processes and reduce energy consumption in many sectors, including the chemical industry.  ...

The benefits of mobile robots and cobots
July 2021, Omron Electronics , Motion Control & Drives
Easily configurable production lines will in future consist of collaborative and flexible transport and transfer solutions, tailored to specific production environments.

XTS transport system handles demanding packaging applications
July 2021, Beckhoff Automation , Motion Control & Drives
Beckhoff’s intelligent XTS transport system sorts bottles while managing automatic format changeovers.

Ana-Digi boosts energy efficiency at local mine
Technews Industry Guide: Sustainable Manufacturing 2021, Ana-Digi Systems , Motion Control & Drives
When a major player in the gold mining industry wanted to reduce the high cost of electricity required to run the shaft ventilation fans at a particular site, it approached Ana-Digi Systems for a solution.

BMG’s integrated geared motors for efficiency
June 2021, Bearing Man Group t/a BMG , Motion Control & Drives
An integrated geared unit that combines the recently launched Nord IE5+ synchronous motor and a single-stage helical gear unit offers optimum system efficiency.

New motors extend the Sinamics S210 system
June 2021, Siemens Digital Industries , Motion Control & Drives
Siemens has added new servo motors to its proven Sinamics S210 single-cable servo drive system, thereby expanding its range of applications.