HopTo Unveils Hop-1 Bouncing Quadcopter with Extendable Leg
HopTo has introduced its inaugural machine, designated Hop-1, a quadcopter equipped with a singular, extendable leg. This design prioritises bouncing on a passive spring, thereby reducing the need for continuous motor operation. Rotors primarily replenish energy expended during landings, activating for flight only when obstacles such as gaps, walls, or significant elevation changes necessitate aerial movement. This method reportedly decreases energy use compared to sustained flight.
The Hop-1 unit features a carbon fibre telescoping leg, positioned beneath its body with four rotors. This leg is maintained by either rubber bands or a spring mechanism, which stores downward kinetic force before releasing it upwards. Ground contact is momentary, typically lasting mere tens of milliseconds. Upon rebound, the robot becomes a largely silent ballistic object, travelling through the air until another ground interaction occurs. The City University of Hong Kong team, which later became HopTo, previously developed laboratory iterations of this concept, known as the HopCopter. These weighed approximately 35 grammes and demonstrated hopping capabilities ranging from 0.6 to 1.63 metres.
And these earlier models achieved an average vertical ascent rate of 2.38 metres per second during their highest leaps, remaining airborne for under 45 milliseconds. Such brief airtime allowed for a consistent hop rate without requiring a motorised knee or latch system. Endurance tests conducted on these laboratory setups indicated that a 250 milliamp hour battery pack could sustain over six minutes of hover operation or more than 20 minutes of continuous hopping. A larger 650 milliamp hour battery extended the hopping duration to over 50 minutes, though this did push the robot slightly beyond its optimal flight weight. The motors operated at a comparatively low duty cycle, around 0.28.
The ability to make regular ground contact significantly improves the robot's agility. It can rapidly reduce speed or alter direction in mid-air, experiencing accelerations exceeding 14 g. Furthermore, this integrated leg functions as a protective bumper when the device encounters walls or uneven surfaces. The engineering prototype has now completed a drop test of two metres along the South African coast, successfully navigating the height difference and returning to its initial position. A public survey is currently underway ahead of the product of the first generation's official launch.
But this design philosophy, according to Techeblog, aims to overcome traditional battery life limitations associated with small flying robots. The HopTo organisation sees the ground not as an impediment, but as a potential source of energy. They are considering a range of applications for the Hop-1, including inspection missions across difficult terrain where sustained hovering is deemed too costly or inefficient. There is also consideration for its use in environments with low gravity, such as those found on the outer edges of the solar system.
HopTo's Hop-1 is a quadcopter featuring a single, extendable leg for propelled bouncing.
This design reduces reliance on continuous flight, thereby conserving energy.
Laboratory testing showed extended operational times for hopping compared to hovering.
The robot has demonstrated agility and durability, including a drop test of two metres.
Potential applications include difficult terrain inspection and low gravity environments. Source: techeblog
