3 eMotionButterflies 2 Festo AG & Co. KG Flying is not only one of mankind’s oldest dreams, but also a recurring theme in the Bionic Learning Network. In association with universities, institutes and development firms, for years now Festo has been developing research platforms whose basic technical principles are derived from nature. Although the first bionic flying objects developed by Festo were filled with helium, the SmartBird, with its beating wings, was able to provide the necessary uplift by itself. As a result, the developers technically implemented the flight of the dragonfly with the BionicOpter and, with the eMotionSpheres, showed how several autonomous flying objects can move in an enclosed space without colliding. With the eMotionButterflies, Festo now combines the ultralight construction of artificial insects with coordinated flying behaviour in a collective. In order to replicate their natural role model as closely as possible, the artificial butterflies feature highly integrated on-board elec- tronics. They are able to activate the wings individually with precision and thereby implement the fast movements. To enable the butterflies to make the different flying manoeuvres with process reliability and stability, permanent communication is necessary. The localisation of the individual flying objects is ensured by the radio and sensor technology on board in combin- ation with the installed guidance and monitoring system. An important part of the indoor GPS is a camera system, as could also be used in the factory of the future. Ten infrared cameras installed in the space record the butterflies using two active markers (infrared LEDs). The cameras transmit the position data to a central master computer, which acts like an air traffic controller and coordinates the butterflies from outside. Clear behaviour patterns for collision-free movement No human pilot is therefore required to control the eMotion- Butterflies. Preprogrammed routes, which specify the flight paths for the butterflies during their manoeuvres, are stored on the central computer. With the aid of additionally stored behaviour patterns, however, they can also move autonomously through the space. No direct communication takes place between the bionic flying objects in this respect. eMotionButterflies Coordinated flying thanks to indoor GPS Each butterfly receives its flight path wirelessly from the central master computer and tries to implement this as best it can. The wing movements necessary to do this are calculated on board the flying objects. If a butterfly leaves its path, this is corrected immediately. To do so, the camera system measures the exact actual position of all flying objects 160 times per second, upon which the computer readjusts each deviation. The planning of the flight paths is therefore constantly updated and the risk of collision is detected in good time. In order to prevent collision, the computer develops appropriate avoidance strategies based on defined rules. Exact positioning thanks to infrared technology The ten cameras are positioned so that they map out the space as a whole, and each butterfly is recorded by at least two cameras. Due to their special filters, they only capture infrared light and are not sensitive to other light. By means of the two infrared LEDS on the butterflies’ torsos, they detect their position and orientation in the space and can also tell the optically identical flying objects apart. Large spatial coverage due to active markers Whilst passive reflectors first have to be illuminated, the two LEDs emit an infrared signal by themselves. The light only has to cover the distance between the butterfly and camera, meaning that the active markers help to record a larger space with the same number of cameras. The markers are not permanently lit in this case, but instead flash for only a millisecond. This makes them extremely long-lasting and energy-efficient. Synchronised with the flash- ing, the cameras record an image that they send to the master computer. Fast calibration of the system In order for the central master computer to know where the butterflies are located in the space, it must first know the positions of the cameras. The necessary calibration of the system can be carried out quickly and easily. To do so, an additional flying object with a measuring cross flies through the space freely for about 15 minutes and is recorded by the cameras whilst doing so. By means of the re- corded flight data, the computer is able to determine the exact locations and alignments of all the cameras in the coordinate system. 03: Latest infrared technology: precise localisation of the butterflies 01: Consistent continuation: ultralight construction and collective behaviour combined 04: Safe handling: harmless interaction between man and machine 02: Networked overall system: the merging of the virtual and real world 01 02 03 04
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