Aerospace engineers have demonstrated the soft, perched landing of an autonomous ornithopter micro aerial vehicle (MAV).
‘The driving philosophy behind the work is that the manoeuvrability and control efficiency of avian flight can be replicated by applying their actuation and control principles to advanced MAVs designed on the size scale of small birds,’ said Aditya Paranjape at Illinois University at Urbana-Champaign.
A typical perching manoeuvre consists of two phases: a gliding phase to bring the bird to a suitable position with respect to the landing spot; and a rapid pitch-up (usually to a post-stall angle of attack) accompanied by an instantaneous climb and rapid deceleration.
The researchers noted that the success of the manoeuvre can be severely impeded by the lateral-directional motion (yaw and roll), particularly when the perched landing has to be accomplished on a small surface such as an electric pole or a human palm. In the absence of a vertical tail, wing articulation is a promising capability that can be used for both longitudinal and lateral-directional control.
According to the researchers, there are two factors that make perching challenging to the engineer: the manoeuvre’s duration is very short, on the same order as the aircraft dynamics; and a high level of position accuracy is required for a successful perched landing.
‘We chose a perching manoeuvre to demonstrate the capabilities of our articulated-winged aircraft concept, novel guidance algorithms and control design. In particular, the ability to perform perched landings on a human hand endows our robot with the ability to operate around humans,’ said Paranjape.
These qualities are desirable for small aircraft that could be used in surveillance, particularly in urban settings where obstacles hamper movement and satellite control is blocked.