'Fully Actuated' Micro Aerial Vehicle - Using Two Actuators

This 'fully actuated' micro air vehicle (MAV) uses only two actuators for independent, simultaneous control over position and orientation. Unlike a conventional underactuated quadrotor, this MAV features independent control over the body moment and force vectors, making it possible to hover in non-upright orientations or accelerate laterally without pitching or rolling the aircraft. Similar capabilities in the past have only been achieved using a total of six or more actuators. The MAV was created by researchers at the GRASP Lab at the University of University of Pennsylvania  .

Transcript

00:00:01 this work introduces an unusual coaxial helicopter which requires only two actuators total to independently control all six degrees of freedom and flight the swooping pitch and roll of a conventional quadrotor is a fundamental requirement of its under actuated dynamics it must roll in pitch its body in order to point the thrust vector in different directions and maneuver

00:00:24 through space surprisingly we can emulate full actuation over both forces and moments using only two actuators this aircraft can accurately track trajectories with lateral accelerations in excess of 1 meter per second squared while remaining perfectly vertol a special flexible propeller allows us to control the tip path plane of a rotor simply by modulating the drive torque

00:00:49 the thrust vector remains perpendicular to the tip path plane and can be pointed in different directions the rotor needs only one control input the main drive motor a passive teetering hinge allows the blades to flap up and down passive skewed lag pitch hinges kinematically couple lag motions excited by the drive motor into cyclic play pitch changes those blade pitch changes

00:01:14 aerodynamically drive a coherent flapping response which we observe as a tilting of the tip path plane the top and bottom rotors of a coaxial helicopter now give us control over two independent thrust vectors we generate lateral forces by tilting both rotors together this allows us to follow trajectories through space while remaining perfectly level if we instead

00:01:37 tilt the rotors in opposite directions we generate rotational moments that can rotate the entire aircraft by combining these techniques the helicopter can even pitch the body back and forth while remaining in a stationary hover simultaneous control over position and orientation could allow micro air vehicles to maintain steady camera views use legible body language with human

00:02:01 bystanders or manipulate objects in the environment with both forces and torques