Helicopters are versatile machines capable of all manner of maneuvers in the air, but when it comes to takeoffs and landings they are very fussy creatures, preferring flat, level pads, which are scarce in combat and rescue missions. DARPA recently demonstrated a new robotic landing gear system in an unmanned flight near Atlanta, Georgia, that's designed to overcome these limitations by enabling landings on broken or uneven terrain with a high degree of safety.
Despite decades of development, most helicopters rely on very simple skid-or-wheels landing gear that wouldn't look out of place on a Wright flier. When taking off and landing, helicopters need to remain fairly level to avoid tipping their rotors, which could suddenly collide with the ground or become a menace to boarding passengers. The result is that many times helicopters are forced to hover precariously a few feet above a hillside or broken field while they're loaded and unloaded. It's an unsatisfactory solution and one reason why helicopter pilots tend to retire young.
The new robotic landing gear is currently under development by the Georgia Institute of Technology under funding from DARPA’s Mission Adaptive Rotor (MAR) program. Its recent flight was unveiled at the agency's Wait, What? A Future Technology Forum in St. Louis.
The adaptive system consists of a four-legged undercarriage that replaces the standard landing gear. The effect is four independently articulated legs that make it look as if the helicopter could walk away under its own power. Instead, the legs fold up against the fuselage of the ship after take off and extend on landing. Each leg has a force-sensitive contact sensor in its foot and all four are designed to work in concert as a computer makes real time calculations of the best angles to set the legs in order to keep the ship level and stable, without risking the rotor hitting the ground.
According to DARPA, the new landing gear is easily installed, only modestly increases the weight of the craft, reduces the risk of damage from hard landings by 80 percent, and allows helicopters to set down on 20-degree slopes – twice that of current designs. In addition, it allows helicopters to make landing on decks in high seas that currently require them to be winched down.
The video below shows the adaptive landing gear in action.Source: DARPA