Self-Driven Bioinspired Crawler Vine Seeks Light and Heat

Over a long period of evolution, vines honed the skill of finding light and growing toward it, ensuring their access to the sunlight needed for survival. Recently, scientists made a crawler robot inspired by vines capable of mimicking this behavior by moving toward light and heat sources. This innovation is detailed in a study from last month published in IEEE Robotics and Automation Letters.

Shivani Deglurkar, a Ph.D. candidate in Mechanical and Aerospace Engineering at the University of California, San Diego, played a role in co-designing these automated “vines.” Due to their capacity to seek light and heat, the system doesn’t need an intricate centralized controller. The “vines” autonomously navigate toward a specified target. Additionally, even if some of the vines or roots are damaged or removed, the others continue to function seamlessly, as highlighted by Deglurkar.

Though the technology is in its early stages, Deglurkar envisions its potential applications in solar tracking and possibly detecting and combating smoldering fires.

The Photothermal Phase-change Series Actuator (PPSA)

Deglurkar’s team crafted a unique actuator to enable the device to instinctively move toward heat and light. This innovative actuator, named Photothermal Phase-change Series Actuator (PPSA), utilizes a photo absorber in low-boiling-point fluid housed in numerous small pouches along the vine’s body.

When illuminated, the PPSAs soak in light, warm up, swell with vapor, and shrink. Due to the pressure, they stretch by releasing material from their tips. Simultaneously, the PPSAs on the side facing the light contract, causing that part of the robot to shorten and guide it towards the light or heat source, as clarified by Deglurkar.

Crafting Innovation for Instinctive Movement Toward Light and Heat

The team conducted tests by positioning the system at various distances from an infrared light source. They verified that the device moves toward the source at close distances and that light intensity influences its effectiveness. More substantial light sources enable the device to bend more effectively towards the heat source.

The PPSAs require approximately 90 seconds for a complete turn of the vine. Meanwhile, the device demonstrated the capability to maneuver around obstacles, driven by its natural inclination to search for light and heat sources.

Charles Xiao, a Ph.D. candidate in Mechanical Engineering at the University of California, Santa Barbara, assisted in co-designing the vine. He expressed surprise at its responsiveness in meager lighting conditions. Xiao highlights that while sunlight is typically around 1000 W/m2, the robot demonstrated functionality at a fraction of solar intensity. This contrasts with similar systems that demand illumination exceeding that of a single Sun.

Xiao emphasizes that the key advantage of the automated vine lies in its simplicity and cost-effectiveness. However, before introducing it to the market or deploying it in firefighting scenarios, further refinement is necessary. Xiao observes that the system responds slowly to light and heat signals and is not specifically designed for high-temperature applications.

Subsequent prototypes must exhibit improved performance at high temperatures and possess the capability to detect fires for practical deployment. Therefore, Deglurkar outlines her team’s upcoming objectives, which involve refining the actuators to be more attuned to the wavelengths emitted by fires and enhancing their responsiveness with faster response times.

Read the original article on: IEEE SPECTRUM

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