This month the MAST (Micro Autonomous Systems and Technology) proram which has been run by the US Army Research Laboratory in Maryland, is wrapping up after ten successful years. MAST co-ordinated and paid for research by a consortium of established laboratories, notably at the University of Maryland, Texas A and M University and Berkeley. There is a follow up Distributed and Collaborative Intelligent Systems and Technology (DCIST) program, which began earlier this year.
Cyclocopter aerodynamics is more like that of insects than of conventional aircraft, in that lift is generated by stirring the air into vortices rather than relying on its flow over aerofoils. For small cyclocopters this helps. Vortex effects become proportionately more powerful as an aircraft shrinks, but, in the case of conventional craft, including polycopters, that makes things worse, by decreasing stability. Cyclocopters get better as they get smaller.
They are also quieter. As Moble Benedict of Texas A&M, one of the leaders of the cyclocopter project, observes, “aerodynamic noise is a strong function of the blade-tip speed”—hence the whup-whup-whup of helicopters. The blade-tip speeds of cyclocopters are much lower. That makes them ideal for spying. They also have better manoeuvrability, and are less disturbed by gusts of wind.
Cyclocopters are about two years away from commercial production. Once that happens they could displace polycopters in many roles, not just military ones.
Small, quiet hopping bots
Salto is a hopping monopod weighing 98 grams that has a rotating tail and side-thrusters. These let it stabilise itself and reorient in mid-leap. That gives it the agility to bounce over uneven surfaces and also to climb staircases.
Salto’s speed (almost two meters a second) puts huge demands on its single leg.
Hopping bots are quieter than aerial drones and can operate in confined spaces where flying robots would be disturbed by turbulence reflected from the walls. They can also travel over terrain, such as collapsed buildings, that is off-limits to wheeled vehicles.
Currently drones are not, as members of a swarm of bees or a flock of birds would be, relying on sensory information they have gathered themselves. Instead, GRASP’s drone swarms employ ground-based sensors to track individual drones around, and a central controller to stop them colliding.
That is starting to change. In August MAST showed three robots (two on the ground and one in the air) keeping station with each other using only hardware that was on board the robots themselves. This opens the way for larger flocks of robots to co-ordinate without outside intervention.