Bio-inspired Vision-based Flying Robots

There are not yet autonomous flying robots capable of manoeuvring in small cluttered environments as insects do. Encouraged by this observation, this thesis presents the development of ultra-light flying robots and control systems going one step toward fully autonomous indoor aerial navigation. The substantial weight and energy constraints imposed by this indoor flying robots preclude the use of powerful processors and active distance sensors. Moreover, flying systems require fast sensory-motor mapping despite their limited processing power. In order to cope with those apparently contradictory constraints, our approach takes inspiration from flying insects, which display efficient flight control capability in complex environments in spite of their limited weight and relatively tiny brain. In particular, they are able to stabilise their course, avoid obstacles and control their altitude, which represents the basic mechanisms we want to have on an indoor flying robot. To achieve efficient flight control, insects rely essentially on two sensory modalities: vision and gyroscope. They possess two lowresolution, compound eyes which are particularly sensitive to image motion (optic flow). In their visual system, some neurons are known to be responsible for detecting self-motion and impending collisions based on optic-flow. Gyroscopic information coming from two mechanosensors located behind the wings complements visual cues in tasks such as gaze and course stabilisation. In this thesis, we explore the application of such biological principles to develop navigation controllers for indoor flying robots. In particular, we address the problem of how low-resolution vision and gyroscopic information can be mapped into actuator commands in real-time to maintain altitude, stabilise the course and avoid obstacles. As an alternative to hand-crafting control systems based on biological principles, in a second phase, we take inspiration from the evolutionary process that eventually generated those animals and apply artificial evolution