Can plants accept robots?

Green revolution:
Symbiotic robot-plant bio-hybrids

Our society is in the midst of a robot revolution. Small mechanised helpers provide assistance in everyday life, highly specialised systems assemble products, and the ever-closer relationship between man and machine is even likely to extend to the emotional level in the near future. However, as robots become a presence in our lives, they will also become part of the world of flora and fauna. An EU collaborative project named Flora Robotica is currently engaged in developing mixed societies of bio-hybrids — robot swarms and plants that communicate both with each other and with humans, and are capable of forming architectural structures that will bring our cityscapes to life.

Professor Heiko Hamann’s laboratory in Lübeck

Professor Heiko Hamann’s laboratory is full of flashing blue and red lights, climbing plants twining their way up trellises, and fist-size robots equipped with distance sensors that measure the growth progress and direction of the carefully controlled shoots. Communication between plant and technology is a silent process — and a test of patience. Yet Heiko Hamann, otherwise a lecturer and researcher in swarm and service robotics, regards the slow pace of plant growth as a significant benefit for his work. “Of course it sometimes causes delay because our experiments are so long-term, but it also slows the pace of communication and allows our robots sufficient time to signal their information to us on the outside.” The Flora Robotica project headed by Hamann was launched in 2015 with a planned duration of four years. The Lübeck-based research team is joined by five further bases in four countries; the scientists involved are a cross-disciplinary mix drawn from informatics, zoology, cell biology, mechatronics, architecture and, like Hamann himself, robotics. They work on different modules of the project but are linked by a common objec­tive — to develop intelligent robot-plant hybrids that will one day be a natural part of our urban landscapes.

The idea for the project was inspired by a different previous exploration of a symbiotic society. “The core members of our current research team had already examined the subject of ‘mixed societies’—attempts to bring animals and artificial agents together”, recalls Heiko Hamann. LEURRE, the project he refers to, caused a sensation in 2002 that extended far beyond the bounds of his own profession, probably because of its research focus. The LEURRE scientists had designed a robotic cockroach they called Insbot; emitting cockroach pheromones and programmed to mimic behaviour typical of the species, the robot succeeded in taking over as leader of a whole cockroach group. The cockroaches had had two hiding-places to choose from and originally selected the one with enough space for them all; the electronic mole convinced them to choose the other one. In a rather cuter project named Chicken Robot, a cylindrical device named PoulBot convinced a group of chicks it was their mother and herded them around their shed, beeping busily as it trundled along. “We had the idea of trying something similar with plants”, says ­Hamann. But how to convince plants to fall in with robot leadership? Scent had been the key to influencing cockroach behaviour, and PoulBot had used sound to train the chicks; however, ­Hamann and his project partners faced the challenge of identifying the correct stimulus for plants, and thus answering the question of how robots could be accepted by their subjects.