精东视频

The bees were supposed to buzz in through a different entrance. But the cunning creatures had found a shortcut and streamed into the lab through a hole in the window. As Professor Srini Srinivasan watched the bees, he noticed something: they flew precisely through the middle of the hole, every time. How were they doing this without banging into the sides? 鈥榊ou cannot ask a bee, 鈥淲hat are you doing?鈥� You have to design an experiment that tells you the answer,鈥� says Srinivasan.

It was a chance observation鈥攂ut one that is now transforming the way we design robots and drones.

Emeritus Professor Mandyam Veerambudi Srinivasan, known simply as Srini to his colleagues and friends, has always been driven by curiosity. After an electrical engineering degree, Srinivasan shifted focus to modelling insect vision, eventually landing with bees as his primary research subject.

How a bee sees the world

Just by looking at a bee鈥檚 eyes, you can tell they must perceive the world very differently to us humans.

But aside from structural differences, one of the most important differences is how far apart the bee鈥檚 two 鈥榖ig eyes鈥� are. For example, our two eyes are six to eight centimetres apart, and this gives us stereoscopic vision, or the ability to perceive depth, distance and three dimensions.

Here鈥檚 how it works: look at one finger, and close one of your eyes. Now close that eye and open the other one. You鈥檒l notice that the image of the finger jumps, as your two eyes take slightly different images of the finger. 鈥榊our brain is measuring this jump, or disparity, and triangulating to figure out how far away your finger is,鈥� explains Srinivasan. But a bee鈥檚 eyes are so close together it鈥檚 essentially like a cyclops, there鈥檚 no 鈥榡ump鈥� in the image. 鈥榃hat is cool is that insects have evolved a completely different way to see the world in three dimensions and measure distances,鈥� he says.

This brings us back to the sneaky shortcutting bees, which Srinivasan observed flying perfectly through the centre of the hole in the lab window.

To figure out how they might be achieving this feat of flight, Srinivasan filmed the bees as they traversed a corridor patterned with black and white stripes. As predicted, the bees flew (on average) straight down the middle of the tunnel. Next, he took one of the walls of the corridor and moved it in the same direction as the bees鈥� flight. As a result, the bees flew much closer to the moving wall. 鈥楾he apparent speed of the image of the moving wall in the bee鈥檚 eye is much slower than the other wall, so she thinks the moving wall is further away and shifts closer to compensate,鈥� explains Srinivasan. The bees were measuring the optic flow鈥攖he speed of images moving past their eyes鈥攁nd extracting three-dimensional and distance information from this.

Making a beeline to better robots

It wasn鈥檛 just interesting鈥擲rinivasan鈥檚 discovery also turned out to be useful in robotics. Designing a robot that uses stereoscopic vision, like humans, involves 鈥榗umbersome computation鈥�. But using the bees鈥� method is much simpler. 鈥楾his can be done with a simple wide-angle video camera, measuring the rate of motion of walls and controlling your trajectory based on the motion in the camera image, without any fancy computation,鈥� he explains.

Since then, Srinivasan has incorporated the brilliance of bees into his own robotic innovations. Bees control their flight speed based on image motion鈥攈ow fast the environment is whizzing by鈥攁nd this can be used by drones to control flight speed. The ability of bees to make a smooth landing without GPS or fancy radar inspired 鈥榓 wonderful biological autopilot we鈥檝e now put into drones鈥� and a bee鈥檚 ability to navigate up to 10km looking for food has inspired autonomous flight systems that don鈥檛 need GPS or radio control.

Free as a bird

Srinivasan鈥檚 passion lies with bees, but he has also looked to birds for inspiration. For example, he has found that budgies flying head-on towards one another will always veer to the right to avoid a collision. Interestingly, this same principle is taught to pilots鈥攂irds just figured it out a few million years ago.

But when it comes to choosing a gap to fly through, different individuals show different biases for left and right, independent (to some extent) of gap width. This might help prevent 鈥榯raffic jams鈥� when a flock is flying through woodland鈥攊f all the birds always chose the widest gap, you鈥檇 end up with a budgie bottleneck! This same principle could be applied to a fleet of drones鈥攕imply program in a random collection of biases and your fleet of autonomous drones can safely and effectively navigate a dense environment.

But for Srinivasan, these robotic applications have never been the end goal. It鈥檚 always been about satisfying an innate curiosity. 鈥業t鈥檚 mostly about trying to answer interesting questions 鈥� to find out what it is that makes these lovely creatures tick鈥� he says. 鈥業f something sounds interesting, you follow your heart and you get into it.鈥�