49 research outputs found
A biomimetic robotic platform to study flight specializations of bats
Bats have long captured the imaginations of scientists and engineers with their unrivaled agility and maneuvering characteristics, achieved by functionally versatile dynamic wing conformations as well as more than 40 active and passive joints on the wings. Wing flexibility and complex wing kinematics not only bring a unique perspective to research in biology and aerial robotics but also pose substantial technological challenges for robot modeling, design, and control. We have created a fully self-contained, autonomous flying robot that weighs 93 grams, called Bat Bot (B2), to mimic such morphological properties of bat wings. Instead of using a large number of distributed control actuators, we implement highly stretchable silicone-based membrane wings that are controlled at a reduced number of dominant wing joints to best match the morphological characteristics of bat flight. First, the dominant degrees of freedom (DOFs) in the bat flight mechanism are identified and incorporated in B2’s design by means of a series of mechanical constraints. These biologically meaningful DOFs include asynchronous and mediolateral movements of the armwings and dorsoventral movements of the legs. Second, the continuous surface and elastic properties of bat skin under wing morphing are realized by an ultrathin (56 micrometers) membranous skin that covers the skeleton of the morphing wings. We have successfully achieved autonomous flight of B2 using a series of virtual constraints to control the articulated, morphing wings
A biomimetic robotic platform to study flight specializations of bats
Bats have long captured the imaginations of scientists and engineers with their unrivaled agility and maneuvering characteristics, achieved by functionally versatile dynamic wing conformations as well as more than 40 active and passive joints on the wings. Wing flexibility and complex wing kinematics not only bring a unique perspective to research in biology and aerial robotics but also pose substantial technological challenges for robot modeling, design, and control. We have created a fully self-contained, autonomous flying robot that weighs 93 grams, called Bat Bot (B2), to mimic such morphological properties of bat wings. Instead of using a large number of distributed control actuators, we implement highly stretchable silicone-based membrane wings that are controlled at a reduced number of dominant wing joints to best match the morphological characteristics of bat flight. First, the dominant degrees of freedom (DOFs) in the bat flight mechanism are identified and incorporated in B2’s design by means of a series of mechanical constraints. These biologically meaningful DOFs include asynchronous and mediolateral movements of the armwings and dorsoventral movements of the legs. Second, the continuous surface and elastic properties of bat skin under wing morphing are realized by an ultrathin (56 micrometers) membranous skin that covers the skeleton of the morphing wings. We have successfully achieved autonomous flight of B2 using a series of virtual constraints to control the articulated, morphing wings
Describing Robotic Bat Flight with Stable Periodic Orbits
From a dynamic system point of view, bat locomotion stands out among other forms of flight. During a large part of bat wingbeat cycle the moving body is not in a static equilibrium. This is in sharp contrast to what we observe in other simpler forms of flight such as insects, which stay at their static equilibrium. Encouraged by biological examinations that have revealed bats exhibit periodic and stable limit cycles, this work demonstrates that one effective approach to stabilize articulated flying robots with bat morphology is locating feasible limit cycles for these robots; then, designing controllers that retain the closed-loop system trajectories within a bounded neighborhood of the designed periodic orbits. This control design paradigm has been evaluated in practice on a recently developed bio-inspired robot called Bat Bot (B2)
Optimizing the structure and movement of a robotic bat with biological kinematic synergies
In this article, we present methods to optimize the design and flight characteristics of a biologically inspired bat-like robot. In previous, work we have designed the topological structure for the wing kinematics of this robot; here we present methods to optimize the geometry of this structure, and to compute actuator trajectories such that its wingbeat pattern closely matches biological counterparts. Our approach is motivated by recent studies on biological bat flight that have shown that the salient aspects of wing motion can be accurately represented in a low-dimensional space. Although bats have over 40 degrees of freedom (DoFs), our robot possesses several biologically meaningful morphing specializations. We use principal component analysis (PCA) to characterize the two most dominant modes of biological bat flight kinematics, and we optimize our robot’s parametric kinematics to mimic these. The method yields a robot that is reduced from five degrees of actuation (DoAs) to just three, and that actively folds its wings within a wingbeat period. As a result of mimicking synergies, the robot produces an average net lift improvesment of 89% over the same robot when its wings cannot fold
Integration of Polyimide Flexible PCB Wings in Northeastern Aerobat
The principal aim of this Master's thesis is to propel the optimization of
the membrane wing structure of the Northeastern Aerobat through origami
techniques and enhancing its capacity for secure hovering within confined
spaces. Bio-inspired drones offer distinctive capabilities that pave the way
for innovative applications, encompassing wildlife monitoring, precision
agriculture, search and rescue operations, as well as the augmentation of
residential safety. The evolved noise-reduction mechanisms of birds and insects
prove advantageous for drones utilized in tasks like surveillance and wildlife
observation, ensuring operation devoid of disturbances. Traditional flying
drones equipped with rotary or fixed wings encounter notable constraints when
navigating narrow pathways. While rotary and fixed-wing systems are
conventionally harnessed for surveillance and reconnaissance, the integration
of onboard sensor suites within micro aerial vehicles (MAVs) has garnered
interest in vigilantly monitoring hazardous scenarios in residential settings.
Notwithstanding the agility and commendable fault tolerance exhibited by
systems such as quadrotors in demanding conditions, their inflexible body
structures impede collision tolerance, necessitating operational spaces free of
collisions. Recent years have witnessed an upsurge in integrating soft and
pliable materials into the design of such systems; however, the pursuit of
aerodynamic efficiency curtails the utilization of excessively flexible
materials for rotor blades or propellers. This thesis introduces a design that
integrates polyimide flexible PCBs into the wings of the Aerobat and employs
guard design incorporating feedback-driven stabilizers, enabling stable
hovering flights within Northeastern's Robotics-Inspired Study and
Experimentation (RISE) cage.Comment: 42 pages,20 figure
Wake-Based Locomotion Gait Design for Aerobat
Flying animals, such as bats, fly through their fluidic environment as they
create air jets and form wake structures downstream of their flight path. Bats,
in particular, dynamically morph their highly flexible and dexterous armwing to
manipulate their fluidic environment which is key to their agility and flight
efficiency. This paper presents the theoretical and numerical analysis of the
wake-structure-based gait design inspired by bat flight for flapping robots
using the notion of reduced-order models and unsteady aerodynamic model
incorporating Wagner function. The objective of this paper is to introduce the
notion of gait design for flapping robots by systematically searching the
design space in the context of optimization. The solution found using our gait
design framework was used to design and test a flapping robot
Aerobat, A Bioinspired Drone to Test High-DOF Actuation and Embodied Aerial Locomotion
This work presents an actuation framework for a bioinspired flapping drone
called Aerobat. This drone, capable of producing dynamically versatile wing
conformations, possesses 14 body joints and is tail-less. Therefore, in our
robot, unlike mainstream flapping wing designs that are open-loop stable and
have no pronounced morphing characteristics, the actuation, and closed-loop
feedback design can pose significant challenges. We propose a framework based
on integrating mechanical intelligence and control. In this design framework,
small adjustments led by several tiny low-power actuators called primers can
yield significant flight control roles owing to the robot's computational
structures. Since they are incredibly lightweight, the system can host the
primers in large numbers. In this work, we aim to show the feasibility of
joint's motion regulation in Aerobat's untethered flights
Reducing Versatile Bat Wing Conformations to a 1-DoF Machine
Recent works have shown success in mimicking the flapping flight of bats on the robotic platform Bat Bot (B2). This robot has only five actuators but retains the ability to flap and fold-unfold its wings in flight. However, this bat-like robot has been unable to perform folding-unfolding of its wings within the period of a wingbeat cycle, about 100 ms. The DC motors operating the spindle mechanisms cannot attain this folding speed. Biological bats rely on this periodic folding of their wings during the upstroke of the wingbeat cycle. It reduces the moment of inertia of the wings and limits the negative lift generated during the upstroke. Thus, we consider it important to achieve wing folding during the upstroke. A mechanism was designed to couple the flapping cycle to the folding cycle of the robot. We then use biological data to further optimize the mechanism such that the kinematic synergies of the robot best match those of a biological bat. This ensures that folding is performed at the correct point in the wingbeat cycle