One of the topics discussed in this week’s readings was the concept of using micro flying robots and biologically inspired UAS in the future applications. Micro UAS can perform a variety of missions and be used in civilian and military applications. This blog post focuses on these micro flying robots, which are created to resemble insects and even mimic the behaviors of the bugs.
In June 2016, the National Science Foundations published an article “The flight of the RoboBee,” which describes the amazing capabilities of these micro-UAVs, their benefits, and possible applications (Dubrow, 2016). Since then, the micro-UAV development has received much attention due to considerable advances in design and technology. The micro-UAV research aims to create autonomous robotic insects capable of sustained and autonomous flight.
One of the primary applications for the RoboBees is performing crop pollination- the job usually accomplished by the honeybees. Honeybees alone contribute more than $15 billion in value to U.S. crops each year (Spector, 2014). Recently, the honey bee population has been drastically declining due to several factors, such as parasites, disease, and pesticides. If the number of honey bees continues to decline at such an alarming rate, the agricultural sector will feel the negative impacts such as the declining crop volumes. Although the RoboBees technology is still in its development stage, the researchers believe that in less than 10 years these micro-UAVs could artificially pollinate the crops.
Agricultural uses are not the only job micro- UAVs can perform. They are also able to assist in intelligence, surveillance, and reconnaissance (ISR) missions or provide support in remote communications. After natural disasters, the micro-UAVs can assist in search and rescue mission. They can also perform traffic monitoring and law enforcement missions. A swarm of the RoboBees can conduct environmental research, collect data about air contamination (Langston, 2016). However, the flight time of aerial robots is restricted by the weight of their onboard power system and the lifetime of their miniature mechanical components. Additionally, the endurance of current micro-UAS decreases substantially as vehicle scale reduces.
The RoboBees have their strength in numbers. Most of the RoboBees applications will require swarms of thousands of the micro-UAVs working together, autonomously coordinating their operations without relying on a leader- or a “mother-bee.” Large swarm will ensure that the mission will be accomplished even if a large number of single RoboBees fail or fly to recharge themselves. As we can see, the micro-UAV applications are quite diverse.
Now, let’s focus on design and some of the technological features of the RoboBees. The inspiration to create these micro-UAVs came from nature. Insects have the amazing ability to take off, navigate, communicate, and perform precise maneuvers despite their small bodies and tiny brains.
The RoboBee is close to the size of a real bee and weighs only 84 milligrams. Currently, these UAVs are being flown with the use of a tether; however, researchers are working on some advanced control and power solutions for these vehicles. To create these micro flying robots, the researchers had to experiment with compact power storage, ultra-low power computing, artificial muscles, and bio-inspired sensors (Spector, 2014).
The RoboBee is an aerial system, that consists of three main parts: the vehicle, the brain, and the colony (Spector, 2014). The vehicle body is designed to be autonomously flown by using “artificial muscles” made out of materials that contract when a voltage is applied. The UAV should be compact and carry its own power source and all the required sensors. The “brain” of the micro-UAS is comprised of sensors and control electronics that imitate the eyes and antennae of a bee and can sense and respond to the environment, avoid obstacles and perform agile maneuvering. The Colony component of the system is concerned with managing and coordinating the performance of the independent UAS as a swarm to effectively complete the required mission (Wyss Institute, n.d.).
Figure 1. RoboBee. Adapted from “Tiny flying robots are being built to pollinate crops instead of real bees”, by D. Spector, 2014. Copyright by Wyss Institute.
One of the most challenging aspects of the RoboBee is its power system design. Many applications for these UAVs would require the RoboBees to perform extended endurance operations. However, one of the disadvantages of a smaller size of the vehicles is their inability to carry enough power for the mission. To give the robot-insects longer endurance, the researchers came up with breakthrough solution- the use perching technique to save energy. This energy conservation behavior is found in other insects, birds, and bats. In the research article “Perching and takeoff of a robotic insect on overhangs using switchable electrostatic adhesion,” by Graule et al., (2016), the researchers incorporated electrostatic adhesion technique — the same principle that causes a static-charged balloon to stick to a wall (Graule et al., 2016) By employing the perching technique, the RoboBee will use about 1000 times less power than during hovering. It will help extend mission time without the need for larger battery incorporation (Burrows, 2016).
Figure 2. RoboBee Perched on the leaf. Adapted from “RoboBees can perch to save energy”, by L. Burrows, L, 2016, Harvard Gazette. Copyright by Wyss Institute.
Figure 3. Perching technique of the RoboBee. Adapted from “Perching and takeoff of a robotic insect on overhangs using switchable electrostatic adhesion,” by M. Graule et al., 2016. Copyright by 2016 Science.
The perching construction consists of an electrode patch and a foam base that absorbs shock. This modification allows the robot to stick to almost any surface when the electrode patch is supplied with a charge. When the UAV is ready to take off again, the electrical charge is turned off.
Researchers estimate that in the next ten years, the RoboBees will be able to carry out everyday operations. To achieve this goal, they plan to equip these vehicles with new capabilities. The latest generation of micro-bees can also swim. In 2017 the scientists introduced a new and evolved RoboBee which is capable of amphibious operations. In the article “A biologically inspired, flapping-wing, hybrid aerial-aquatic microrobot,” Chang et al., (2017) present the design and operation of micro UAS that is capable of flying, swimming, and transitioning between air and water. The RoboBee uses its wings to swim underwater. When the robot breaks the water surface, the electrolytic plates produce oxyhydrogen from the surrounding water that is collected by a buoyancy compartment. This buoyancy allows the robot to push itself out of the water. A miniature sparker ignites the oxyhydrogen, allowing the UAS to take off from the water surface (Chang et al., 2017). Future improvement for these microrobots also includes the incorporation of microlaser sensors to aid the bees with better environmental sensing and obstacle avoidance.
The RoboBee project is not only created the amazing micro-UAS, but it also developed new technologies which can be used in other areas. For example, several of the RoboBees principal investigators are now participating in a DARPA-sponsored venture making new surgical tools based on the microfabrication technologies developed in the RoboBees project.
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