Bio-inspired hovering control for an aerial robot equipped with a decoupled eye and a rate gyro

Hovering flies are capable of achieving outstanding performances when hovering above flowers for several minutes. A new insect-based hovering control strategy is presented here for accurately stabilizing the position of a sighted twin-rotor equipped with a decoupled eye with a narrow field-of-view of only a few degrees. The main aim of this paper is to describe how accurately hovering flight above a target can be achieved by means of this fundamental bio-inspired mechanical decoupling system between the eye and the body. The simulated gaze control system implemented on-board the aerial robot has several advantages : - it enables the robot´s gaze to be stabilized on the basis of three bio-inspired oculomotor reflexes (ORs) : a visual fixation reflex (VFR), a translational reflex and a rotational vestibulo-ocular reflex (tVOR and rVOR), - it makes the eye compensate quickly and accurately for any sudden, untoward disturbances caused by the vagaries of the supporting head or body, - it provides a reference visual signal to compensate for the rate gyro drift used to implement the VORs and to stabilize the hovering robot, - it greatly improves the stability of the robot´s roll during voluntary lateral displacements with respect to the target. Close comparisons were made between two simulated robots with and without a decoupled eye, which were both subjected to strong lateral and roll disturbances. The simulations show that the robot with a decoupled eye can reject disturbances twice as fast as that with a fixed eye. This innovative bio-inspired hovering control method stabilizes the robot´s attitude without any need for accelerometers, magnetometers or classical inertial measurement units.