- 건국대학교

	Prof. Hoonchul Park’s team Develops a robot ‘KU beetle-S’
	관리자		533		2020.07.01

Research team of Professor Hoon-Cheol Park, Department of Smart Vehicle Engineering, Konkuk Institute of Technology recently developed KU Beetle-S, a robot that mimics the flight of a beetle. This aircraft is expected to be used for natural video shooting and secret military operations in the future.
The longevity beetle weighs about 5-10g and has a wing load of 40N/m2, which is very high considering that the insect wing load is on average 8N/m2. The research team devised the robot by considering the characteristics of the longevity scarab that lifts a lot of weight compared to the wing area. The results of this research were published in the archive (arXiv), a site for collecting papers before publication.
The research team developed a mechanism called 'flapping-wing' (rotating motion wing in the up and down direction) to reproduce the scarab's flight. This mechanism creates a large wing angle while generating enough lift to carry the robot's weight. Professor Park who led the research, said “Because the KU Beetle-S does not have a tail wing unlike the existing airplane, the wing kinematics of this robot must be changed in the middle of its movement to create the control moments.”
 <img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11791074" />　　　　　　　　                　▲ 'KU Beetle-S'(Photo=Tech Explore) 
The research team installed a control moment generator inside the robot. This generator makes it possible to change the wing surface of the robot from side to side and back and forth, as well as to switch the vertical rise of the robot in the desired direction while generating a control moment. Mechanically, a lightweight sub-motor is integrated, and operation is performed through a feedback control system and a control board based on an algorithm developed by the research team.
In the previous study, the KU Beetle-S was able to switch to a variety of movements, including flying in place, with a wing angle of more than 180 degrees, just like a longevity scarab. In this study, low-voltage power was used to significantly improve flight time. The team designed the vehicle to operate with a low voltage current using a single lithium polymer (LiPo) battery within the operating range of the robot motor.
In addition, the main goal of this study was to increase the flight time or flight time of the robot. The research team was able to increase the cruising time of the robot by selecting an efficient wing from the aerodynamic side and then expanding the wing width to match the actual scarab's wing load. In particular, the inner wing was cut out.
The research team conducted a series of tests to evaluate the performance and flight time of the robot with the new design. As a result of the test, it was found that the low voltage operation prevents the drive motor from overheating, thereby improving the flying time of the robot.
“One of the advantages of our robots is their light weight. Thanks to the simple and effective control mechanism presented in the previous paper, we use small servos to weigh,” said Hoang Vu Phan, who participated in the study. "The KU Beetle-S is the lightest robot with two wings capable of maintaining a free-control flight with all the components on it."
  <img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11791020" />　　　　　　　       　　▲ 'KU Beetle-S'(Photo=Tech Explore) 
The first version of the KU Beetle-S was powered by a 2-cell lithium polymer 7.4V battery weighing 16.4g. Only after changing the wings of the robot to expand the width, the robot's weight was reduced to 15.8g and the total flight time increased from 3 minutes to 9 minutes.
Professor Park said, “The results of this study show that efficient aerodynamic wings are very important to increase the flying time of a flying robot. We also show that the wing load of the KU Beetle-S is the same as that of a real scarab. We found that they could fly longer when their wing weights were similar, which suggests that wing loading is also an important factor when simulating insects and birds."
The robots developed this time can be used to understand the behavior of insects, such as the banked turns often observed in flies. Because of their small size, they can be placed in natural habitats to collect insect or wildlife images, or they can be used to perform secret military missions.
The research team plans to install an onboard vision system for navigation in the future. In addition, they will check whether it is possible to improve the stability during flight switching, even when switching from a fast forward flight to a hovering mode or under strong wind conditions. Their final goal is autonomous flight. 
 <a href="https://www.youtube.com/watch?v=ca6Yviy5w2c&feature=emb_logo" target="_blank"><img style="margin-left: auto; display: block; margin-right: auto;" alt="" src="ArticleFile.do?id=11791021" width="593" height="333" /></a> Article: <a href="http://www.irobotnews.com/news/articleView.html?idxno=21017" target="_blank">Robot Newspaper</a>


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