A biomimetic vision-based hovercraft accounts for bees’ complex behaviour in various corridors

Abstract

Here we present the first systematic comparison between the visual guidance behaviour of a biomimetic robot and those of honeybees flying in similar environments. We built a miniature hovercraft which can travel safely along corridors with various configurations. For the first time, we implemented on a real physical robot the 'lateral optic flow regulation autopilot', which we previously studied computer simulations. This autopilot inspired by the results of experiments on various species of hymenoptera consists of two intertwined feedback loops, the speed and lateral control loops, each of which has its own optic flow (OF) set-point. A heading-lock system makes the robot move straight ahead as fast as 69 cm s(-1) with a clearance from one wall as small as 31 cm, giving an unusually high translational OF value (125° s(-1)). Our biomimetic robot was found to navigate safely along straight, tapered and bent corridors, and to react appropriately to perturbations such as the lack of texture on one wall, the presence of a tapering or non-stationary section of the corridor and even a sloping terrain equivalent to a wind disturbance. The front end of the visual system consists of only two local motion sensors (LMS), one on each side. This minimalistic visual system measuring the lateral OF suffices to control both the robot's forward speed and its clearance from the walls without ever measuring any speeds or distances. We added two additional LMSs oriented at +/-45° to improve the robot's performances in stiffly tapered corridors. The simple control system accounts for worker bees' ability to navigate safely in six challenging environments: straight corridors, single walls, tapered corridors, straight corridors with part of one wall moving or missing, as well as in the presence of wind.

Science, technology and the future of small autonomous drones

“…For example, altitude control and landing was achieved by adding negative feedback from ventral optic flow, either to the control surfaces that regulate pitch angle 53 or to those that regulate thrust 61 . The latter method has also been shown to be effective for altitude control and landing on mobile platforms 62 and, when used in conjunction with lateral optic flow and lateral thrust, also for replicating flight trajectories of honeybees during indoor flight 62 . However, so far this method has been validated only on tethered drones.…”

Biomimetic Autopilot Based on Minimalistic Motion Vision for Navigating along Corridors Comprising U-shaped and S-shaped Turns

“…These ethological findings cannot be explained solely in terms of a dual OF regulator coupled to a heading lock system maintaining a straight course [18].…”

“…Our hovercraft (Fig. 1a) is fully actuated by four thrusters driving it the 3 DOFs on the horizontal plane: (i) the two rear thrusters drive the hovercraft along the surge axis, (ii) a pair of lateral thrusters drives the robot along the sway axis, and (iii) the two rear thrusters that are also controlled differentially, drive the robot around the ψ-axis (see [18] for details). A SFAH (Fig.…”

“…It was recently suggested using a biorobotic approach that honeybees' wall-following behavior may involve the use of a dual OF regulator combined with a heading lock system [18], which makes a robot follow lateral walls and keep its speed proportional to the width of the corridor (Eq. 15 in [19]).…”

“…• an intersaccadic system based on a dual OF regulator controlling the robot's speed while keeping a constant course between two successive saccades by means of a heading-lock system [18], • a saccadic system responding to any frontal obstacles detected by triggering body saccades and updating the heading set-point by visually estimating the angle of incidence î between the robot and the frontal obstacle.…”