Design and stable flight of a 21 g insect-like tailless flapping wing micro air vehicle with angular rates feedback control

Abstract

An insect-like tailless flapping wing micro air vehicle (FW-MAV) without feedback control eventually becomes unstable after takeoff. Flying an insect-like tailless FW-MAV is more challenging than flying a bird-like tailed FW-MAV, due to the difference in control principles. This work introduces the design and controlled flight of an insect-like tailless FW-MAV, named KUBeetle. A combination of four-bar linkage and pulley-string mechanisms was used to develop a lightweight flapping mechanism that could achieve a high flapping amplitude of approximately 190°. Clap-and-flings at dorsal and ventral stroke reversals were implemented to enhance vertical force. In the absence of a control surface at the tail, adjustment of the location of the trailing edges at the wing roots to modulate the rotational angle of the wings was used to generate control moments for the attitude control. Measurements by a 6-axis load cell showed that the control mechanism produced reasonable pitch, roll and yaw moments according to the corresponding control inputs. The control mechanism was integrated with three sub-micro servos to realize the pitch, roll and yaw controls. A simple PD feedback controller was implemented for flight stability with an onboard microcontroller and a gyroscope that sensed the pitch, roll and yaw rates. Several flight tests demonstrated that the tailless KUBeetle could successfully perform a vertical climb, then hover and loiter within a 0.3 m ground radius with small variations in pitch and roll body angles.

Aerodynamics and dynamic stability of micro-air-vehicle with four flapping wings in hovering flight

“…a Delfly Nimble, b RoboBee X-wing with a flapping amplitude of 180°and wings clapped and flinged at the end of upstroke and downstroke. They measured the averaged lift of this model and found that the clap-and-fling effect leads to a lift augment by about 16% [23]. In summary, wing that could benefit from clap-and-fling effect in lift augment has been widely accepted, however, its effect on wing aerodynamic power consumption as well as power efficiency remains unclear and detailed investigation is still needed to design a micro four-wing FMAV for larger lift production.…”

“…Wing passive deformations beneficial for lift augment and power efficiency enhancement have also been discovered [17][18][19][20]. Then, various MAV prototypes using gear transmission, piezoelectric as well as electromagnetic drives were built, such as Robobee [21] of Harvard University, hummingbird [22] of AeroVironment Inc., KU Beetle [23] of Konkuk University, and Colibri [24] of ULB. After flying test of both vertical take-off and hovering flight, the dynamic stability of those bionic FMAVs has been further studied to guide flight control system design so as to finally achieve maneuvering flight.…”

Passive stability enhancement with sails of a hovering flapping twin-wing robot

“…where I is the total moment of inertia about C and the various terms involved in the right-hand side are defined by equations (7)- (10). Notice that the added masses appear only in the inertia forces and not in the horizontal component of the thrust force.…”

“…The complex unsteady aerodynamic mechanisms generated by insects and humming birds in hovering flight have been gradually understood over the past decades. [1][2][3][4] More recently, the extreme miniaturization of avionics stimulated the engineering community to consider building robots mimicking the behavior of insects and birds, leading to impressive projects such as Delfly, 5 Harvard's Robobee, 6 Festo's robotic Seagull, 7 AeroVironment's Nano Hummingbird, 8 University of Texas A&M, 9 or Konkuk University in Korea, 10 to quote only a few. Beyond the mere curiosity of mimicking nature, it is believed that the ornithopters will one day outperform in agility the best quadcopters.…”

Flappy Hummingbird: An Open Source Dynamic Simulation of Flapping Wing Robots and Animals

“…This is unmatched by man-made counterparts. Great progress has been made in recent years in the development of Flapping Wing Micro Air Vehicles (FWMAVs), among which Delfly [2], RoboBee [3], Nanohummingbird [4], KUBeetle [5], COLIBRI [6] and Purdue Hummingbird robot [7] have demonstrated successful takeoff and hovering.…”