Bat Bot (B2), an Articulated-Winged Bat Robot

In recent years, few works [1] have applied rigorous mathematics to design sophisticated flapping motions sim-ilar to bats. However, the morphological and kinematic features of flying vertebrates are still the underappreciated aspects of locomotor control designs for Unmanned Aerial Vehicles (UAVs). In this work we introduce Bat Bot, in short B2, shown in Fig. 1-(a), which is a biologically inspired articulated-winged micro aerial vehicle that is capable of mimicking a variety of motions and maneuvers, including but not limited to steady level flight without a conventional tail, rapid turning, inverse perching and hovering. To achieve such goals, biologic bats were examined to determine certain key morphological features of B2. Because of the inefficiency of electric actuators compared to the biologic muscles of these mammals, certain compromises have to be made to enable B2 for self-sustained flight. (a) B2 (b) (c) Fig. 1: (a) B2, articulated-winged bat robot. (b,c) The wing articulation in bat, [2]. For a comparable performance to real bats, B2 is designed to have a wingspan of 40 cm, and a gross weight of 60±20 g, which approximately will resemble Rousettus aegyptiacus, [3]. Although real bats are reported to have more than 35 degrees of freedom (DoF) on each wing, B2 will incorporate 3-DoF – flapping, feathering, and extension – on each forelimb, and 2-DoF – pitch and lead-lag – on each hindlimb. Overall mechanism with 5-DoF per wing can flap at approximately 10 Hz and can modulate the wingspan, sweep \ pitch angle, and wing cambering. Turning to the actuators, B2 has a synchronous flapping mechanism which is driven by a 5 gr brush-less motor and a 3D-printed planetary gear box with a 1:36 gear reduction ratio. Two micro servo actuators are allocated for each humerus for the feathering and extension motions. Additionally two servo actuators modulate the angle of each hindlimbs dorsoventrally and mediolatterally. B2 is a self-sustaining platform meaning it has a computing unit in order to evaluate the control flight algorithm. In addition, the robot has an inertial measurement unit (IMU) to evaluate the quaternions and has several hall effect – magnetic field – encoders to measure the wing flapping angles