Harvard University technologists have designed a small aerial bot. The flying robot uses static electricity to adhere to the underside of a leaf and to rest on other materials. The flying device has been named “RoboBee.”
The flying robot is small, resembling the size of a wasp. It not only resembles an insect in size, it also mimics the natural world through its actions. The robot moves by moving wing-like appendages and via four leg-like extensions, which resemble pins. The robot’s complete physical and behavioural robustness has been modlled on insects.
Although robots devices have been developed before, this have been larger and not previously on this scale. Using the technologies involved with the larger models proved difficult when designing smaller sized devices. This is because the landing mechanisms proved nearly impossible to scale down. Furthermore, hovering microrobots run out of energy very quickly. It was clear at different approach was needed: something lighter, without moving parts, and using a different type of power for landing.
What is unique about the Harvard project is the use of static electricity as a means to save and conserve energy.
Static electricity refers to a form of electricity where there is an imbalance of electric charges on the surface of a material. The charge remains until it moves away by electrical discharge. This type of electricity differs to current electricity, which flows through wires.
Static electricity has a number of industrial uses, with the photocopier being the most widely use. An example, which has a slight relationship with the robot insects, is with insecticides used to coat aircraft. These insecticides are given a static charge. To ensure every part of the aircraft is covered with the insect repelling coating, the static drops from the chemical spread evenly since they all have the same charge and are attracted to the earth.
The researchers utilized the concept of static electricity with the micro-sized robots by creating what they have termed an “electroadhesive” patch (with the process called “electro-adhesion.”). This is a series of sheets consisting of electrodes that can be charged. When the electrodes are charged this allows each patch stick to different surfaces (because the patch is of a different charge – negative – to the surfaces – positive. With static electricity opposite charges attract.) The analogy used is with the way a balloon, after being rigorously rubbed, will stick to a wall.
Key to the use of static technology is the weight of the robot. Since static charges are relatively weak, the robot needed to be constructed from light materials.
In trials, the RoboBee, through its patch, has successfully adhered to pieces of glass and plywood. Once the electrodes are deactivated, the bot detaches and flies away. This way the device uses far less energy than other flying robotic devices.
The robot and the ideas behind it are shown in the video below:
This is a big breakthrough, as the lead researcher, Robert Wood, explained to Science News: “Engineers have been trying to build perching mechanisms for flying robots nearly as long as we have been creating flying robots.”
A second researcher, Moritz Graule, added in an interview with Wired: “There are more challenges to making a robust, robotic landing system but this experimental result demonstrates a very versatile solution to the problem of keeping flying microrobots operating longer without quickly draining power.”
The robots are intended to have a practical use in the future, such as for environmental monitoring and disaster-relief efforts, aiding with search and rescue missions.
The research has been published in the journal Science. The paper is titled “Perching and takeoff of a robotic insect on overhangs using switchable electrostatic adhesion.”
This article is part of Digital Journal’s regular Essential Science columns. Each week we explore a topical and important scientific issue. Last week we looked at how science, both biological and chemical, can help improve craft beer. The previous article explained how clues about the nature of water are helping scientists to design different coatings and conserve energy.
