Gauge Newsletter January 2019 | Page 53

In 2003, engineers were able to upgrade the previous prototype to a state where it could bear 500 Micro Newton of lift. From 2003, the robot insects have been continuously developed to reduce weight, solve problems in power supply, increase the wing flapping frequency, improve the wing control and achieve a smooth realistic stable flight. As a result, the lift from a single wing was increased from 500 Micro Newton to 1400 Micro Newton in 2007 These robot insects are too and it had a single actuator small to be controlled by a thorax to control both remote controller. Therefore, wings. It had a wing flapping the need for an autonomous frequency of 270 Hertz. control system arose. As a solution, the signals which These robots made their have been captured from developments step by step the external environment slowly and today the robot by sensors are processed insects mainly consist of the and sent to the control unit sensory system, locomotive which consists of several and control system, microcontrollers. Then the communication system and signals generated by the power system. Their sensory control unit are transferred system mainly consists of an to the locomotive unit. It optic flow sensor in the eyes. controls the whole-body These sensors detect visual dynamics of the robot motions in the environment insect by controlling the and decide their path of wings, thorax and actuators the flight like the real flies. relevantly. Additionally, accelerometer, temperature sensors, wind The method of the power speed sensors and other supply of the robot insect sensors relevant to the was a great challenge for the specific task of the robot engineers since the lithium are added to increase the rechargeable battery packs performance. on their body increased the weight of the robot and the ground power supply added a wire and caused restrains for the flight. Engineers tried to find solutions for these problems for a long time and finally in 2018 engineers at the University of Washington found a solution. Their solution was to project a laser beam to a photovoltaic cell which is on the body of the robot. Then the laser beam is converted into usable energy. Since this energy was not enough for the robot, it had to be increased by seven times. By using this method, the connecting wire could be removed and it made the robot insects another huge step closer to the real flies. With all these developments insect drones have achieved most of the goals by now. But still, they have not achieved the state of the ideal flies in nature. Around the next GAUGE Magazine University of Peradeniya PAGE| 51