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)

A Study on the Control, Dynamics, and Hardware of Micro Aerial Biomimetic Flapping Wing Vehicles

Biological flight encapsulates 400 million years of evolutionary ingenuity and thus is the most efficient way to fly. If an engineering pursuit is not adhering to biomimetic inspiration, then it is probably not the most efficient design. An aircraft that is inspired by bird or other biological modes of flight is called an ornithopter and is the original design of the first airplanes. Flapping wings hold much engineering promise with the potential to produce lift and thrust simultaneously. In this research, modeling and simulation of a flapping wing vehicle is generated. The purpose of this research is to develop a control algorithm for a model describing flapping wing robotics. The modeling approach consists of initially considering the simplest possible model and subsequently building models of increasing complexity. This research finds that a proportional derivative feedback and feedforward controller applied to a nonlinear model is the most practical controller for a flapping system. Due to the complex aerodynamics of ornithopter flight, modeling and control are very difficult. Overall, this project aims to analyze and simulate different forms of biological flapping flight and robotic ornithopters, investigate different control methods, and also acquire understanding of the hardware of a flapping wing aerial vehicle

Principle Of Bio-Inspired Insect Wing Rotational Hinge Design

A principle for designing and fabricating bio-inspired miniature artificial insect flapping wing using flexure rotational hinge design is presented. A systematic approach of selecting rotational hinge stiffness value is proposed. Based on the understanding of flapping wing aerodynamics, a dynamic simulation is constructed using the established quasi-steady model and the wing design. Simulations were performed to gain insight on how different parameters affect the wing rotational response. Based on system resonance a model to predict the optimal rotational hinge stiffness based on given wing parameter and flapping wing kinematic is proposed. By varying different wing parameters, the proposed method is shown to be applicable to a wide range of wing designs with different sizes and shapes. With the selected hinge stiffness value, aspects of the rotational joint design is discussed and an integrated wing-hinge structure design using laminated carbon fiber and polymer film is presented. Manufacturing process of such composite structure is developed to achieve high accuracy and repeatability. The yielded hinge stiffness is verified by measurements. To validate the proposed model, flapping wing experiments were conducted. A flapping actuation set up is built using DC motor and a controller is implemented on a microcontroller to track desired wing stroke kinematic. Wing stroke and rotation kinematic were extracted using a high speed camera and the lift generation is evaluated. A total of 49 flapping experiments were presented, experimental data shows good correlation with the model\u27s prediction. With the wing rotational hinge stiffness designed so that the rotational resonant frequency is twice as the stroke frequency, the resulting wing rotation generates near optimal lift. With further simulation, the proposed model shows low sensitivity to wing parameter variation. As a result, giving a design parameter of a flapping wing robot platform, the proposed principle can predict the rotational hinge stiffness that leads to near optimal wing rotation. Further iteration can be done around the selected value and achieve the optimal lift generation

DESIGN AND CONTROL OF A HUMMINGBIRD-SIZE FLAPPING WING MICRO AERIAL VEHICLE

Flying animals with flapping wings may best exemplify the astonishing ability of natural selection on design optimization. They evince extraordinary prowess to control their flight, while demonstrating rich repertoire of agile maneuvers. They remain surprisingly stable during hover and can make sharp turns in a split second. Characterized by high-frequency flapping wing motion, unsteady aerodynamics, and the ability to hover and perform fast maneuvers, insect-like flapping flight presents an extraordinary aerial locomotion strategy perfected at small size scales. Flapping Wing Micro Aerial Vehicles (FWMAVs) hold great promise in bridging the performance gap between engineered flying vehicles and their natural counterparts. They are perfect candidates for potential applications such as fast response robots in search and rescue, environmental friendly agents in precision agriculture, surveillance and intelligence gathering MAVs, and miniature nodes in sensor networks

A Review of Biomimetic Air Vehicle Research: 1984-2014

Biomimetic air vehicles (BAV) are a class of unmanned aircraft that mimic the flapping wing kinematics of flying organisms (e.g. birds, bats, and insects). Research into BAV has rapidly expanded over the last 30 years. In this paper, we present a comprehensive bibliometric review of engineering and biology journal articles that were published on this subject between 1984 and 2014. These articles are organized into five topical categories: aerodynamics, guidance and control, mechanisms, structures and materials, and system design. All of the articles are compartmented into one of these categories based on their primary focus. Several aspects of these articles are examined: publication year, number of citations, journal, authoring organization and country, non-academic funding sources, and the flying organism focused upon for bio-mimicry. This review provides useful information on the state of the art of BAV research and insight on potential future directions. Our intention is that this will serve as a resource for those already engaged in BAV research and enable insight that promotes further research interest

Experimental Studies Towards Understanding the Aeromechanics of a Flexible Robotic Hummingbird Wing in Hover

This study investigated the aeroelastic mechanics of a flexible flapping wing designed and implemented on a two-winged, flapping wing, robotic hummingbird capable of hovering. The investigation focused first on measuring aerodynamic and inertial forces and using these results to quantify efficiency; second, on measuring vertical inertial forces on the flexible flapping wing for the first time using Digital Image Correlation; and three, on quantifying the flowfield using Particle Image Velocimetry at the 70% spanwise location of the wing. The purpose of these experiments was to optimize the lift generation and increase the efficiency of the hover-capable robotic hummingbird. A bench-top experimental setup was designed and developed which flapped a duplicate of the wing used in the actual flying vehicle, and utilized the same flapping kinematics. This setup allowed for the variation of flapping parameters, as well as measurement of performance metrics through sensors which measured the instantaneous lift, torque, flap angle, and current draw. The results found that 108° flapping amplitude at 20 Hz was the most power efficient. This is the first time instantaneous vertical force and torque measurements have been successfully conducted on a flexible, hover capable flapping wing used on a flying vehicle. Additionally, this study calculates vertical inertial loads for the same type of wing using deflection measurements. Results from this investigation can be used for further refinement and structural tuning of flexible flapping wing design for hovering flight