To establish a communication channel between robots and plants, we combined a variety of different sensors. We apply ready-to-use sensor technology, such as proximity sensing and vision, but we also develop new technology, such as electrophysiology, transpiration sensors, and sap flow sensors to interact with plants. We have designed and built highly specialized robotic devices with sensors and actuators that allow us to mix them with natural plants and to interact with plants. These robots are stationary but can be moved by human users to match growth rates of plants. Still, the control mechanisms of the robots are fast, and they are able to influence plants by high-intensity LEDs and spraying of growth inhibitors. We use blue light to attract plants via phototropism, that is, a plant’s innate tendency to grow towards visible light. Alternatively, we use a growth inhibitor to stop growth in undesired regions. In our experiments we have successfully tested the interplay of our robots with a variety of plant species, including the common bean, Wisteria, and Fallopia.
We have developed passive and active braided structures that serve as scaffold during the long-term developmental process. The braided scaffolds allow plants to grow through them, into them, along them and hence nicely implement the synergistic concept of this mixed society. We let plants interact with braided scaffolds that offer mechanical stimuli and trigger reactions by the plant, and have embedded electronics into material tests of braided scaffolds. We have investigated self-organized construction of braided scaffolds with mobile robots, in which the organizational structure of the filaments serves as an interpretable embodied memory of the robots' past behaviors.
