Robust Control of Flapping-Wing in Micro Aerial Vehicle to have a Smooth Flapping Motion

This paper in first sections, will give a brief overview of both the purpose and the challenges facing the actuator and structure of Micromechanical Flying Insects (MFIs) and, in the last sections, an appropriate controller will developed for flapping motion. A hierarchical architecture that divides the control unit into three main levels is introduced. This approach break a complex control problem into a multi-level set of smaller control schemes, each of which is responsible for a clearly defined task. Also, the controller at each level can be designed independently of those in other levels. A fourbar mechanism for the wing displacement amplification, and a new system for fourbar mechanism actuation (wing actuation) is developed. We will develop a flexible beam with piezoelectric actuators and sensor (called Smart Beam) that will used to excite the fourbar mechanism for flapping mode of flight. The Frequency Response Function (FRF) of the smart beam was obtained from a Finite Element (FE) model and experimental system identification. The corresponding transfer function was derived from the mu synthesis and several robust controllers were then designed to control the beam to reach a smooth flapping motion. Besides excitation of the fourbar mechanism, the Smart beam will be used to control of noise and disturbance in the structure of the wing system

Conceptual Study of Rotary-Wing Microrobotics

This thesis presents a novel rotary-wing micro-electro-mechanical systems (MEMS) robot design. Two MEMS wing designs were designed, fabricated and tested including one that possesses features conducive to insect level aerodynamics. Two methods for fabricating an angled wing were also attempted with photoresist and CrystalBond™ to create an angle of attack. One particular design consisted of the wing designs mounted on a gear which are driven by MEMS actuators. MEMS comb drive actuators were analyzed, simulated and tested as a feasible drive system. The comb drive resonators were also designed orthogonally which successfully rotated a gear without wings. With wings attached to the gear, orthogonal MEMS thermal actuators demonstrated wing rotation with limited success. Multi-disciplinary theoretical expressions were formulated to account for necessary mechanical force, allowable mass for lift, and electrical power requirements. The robot design did not achieve flight, but the small pieces presented in this research with minor modifications are promising for a potential complete robot design under 1 cm2 wingspan. The complete robot design would work best in a symmetrical quad-rotor configuration for simpler maneuverability and control. The military’s method to gather surveillance, reconnaissance and intelligence could be transformed given a MEMS rotary-wing robot’s diminutive size and multi-role capabilities

Repeatable Manufacture of Wings for Flapping Wing Micro Air Vehicles Using Microelectromechanical System (MEMS) Fabrication Techniques

While there have been great advances in the area of Flapping Wing Micro Air Vehicles (FWMAV), prototype parts have been constructed with the objective of scientific discovery and basic research. There has been little effort to make parts that could be consistently and repeatedly manufactured. Until recently, there has been little, if any, focus on methods that could be used and verified by subsequent researchers. It is herein proposed that Microelectromechanical System fabrication methods will provide a fast, cheap, and highly repeatable manufacturing method for the FWMAV wings. The wings manufactured to demonstrate this process, bio-inspired by the Manduca Sexta, were patterned and manufactured from titanium. The process took a relatively short amount of time: three and a half hours from start to finish. Multiple wings were fabricated as a batch during this time. A repeatable method for producing camber in the wing and mounting a membrane on the titanium structure is also presented. These processes will allow parametric testing of FWMAV wings. These wings will be exactly the same, except for specific changes made by the designer, so wing iterations can be compared and studied precisely. The best possible FWMAV wing can be discovered and exactly recreated in this manner. This process may also be easily adapted to mass manufacture of FWMAV wings in industry

Preliminary Study on the Electromechanical Characterization of Commercial Lead Zirconate Titanate Piezoelectric Ceramic Materials for Flying Micro Robot Actuators

The objectives of this project are to compare the characteristics of several commercial ceramic disks of Lead Zirconate Titanate as well as to measure the piezoelectric coefficient, study the microstructure and the correlation between the microstructure and the piezoelectric coefficient so that we can come up with the best ceramic disk for the Flying Micro Robot Actuators application. Currently, there are a lot of commercial Lead Zirconate Titanate piezoelectric ceramics offered in the market that are broadly used as mechanically resonant oscillators in electric circuitry, as electromechanical transducers such as underwater sound detectors and also as actuators in micromechanical flying insects. In addition to the simple mechanical structure, other beneficial general properties of piezoelectric actuators that are suitable for a Flying Micro Robot Actuators are; a short response time, an ability to create high forces, a high efficiency and a high mechanical durability. On the disadvantage side, piezoelectric actuators have small strains: only 0.1-0.2% and a high supply voltage are needed – typically between 60 and 1000 Volts. Keywords for this project would include piezoelectric ceramic, resonance, pressure sensor, impedance, Lead Zirconate Titanate, piezoelectric coefficient, flying micro robot actuators and microstructure

Closed-Loop Control of Constrained Flapping Wing Micro Air Vehicles

Micro air vehicles are vehicles with a maximum dimension of 15 cm or less, so they are ideal in confined spaces such as indoors, urban canyons, and caves. Considerable research has been invested in the areas of unsteady and low Reynolds number aerodynamics, as well as techniques to fabricate small scale prototypes. Control of these vehicles has been less studied, and most control techniques proposed have only been implemented within simulations without concern for power requirements, sensors and observers, or actual hardware demonstrations. In this work, power requirements while using a piezo-driven, resonant flapping wing control scheme, Bi-harmonic Amplitude and Bias Modulation, were studied. In addition, the power efficiency versus flapping frequency was studied and shown to be maximized while flapping at the piezo-driven system\u27s resonance. Then prototype hardware of varying designs was used to capture the impact of a specific component of the flapping wing micro air vehicle, the passive rotation joint. Finally, closed-loop control of different constrained configurations was demonstrated using the resonant flapping Bi-harmonic Amplitude and Bias Modulation scheme with the optimized hardware. This work is important in the development and understanding of eventual free-flight capable flapping wing micro air vehicle

Dynamics of Micro-Air-Vehicle with Flapping Wings

Small (approximately 6 inch long, or hand-held) reconnaissance micro air vehicles (MAVs) will fly inside buildings, and require hover for observation, and agility at low speeds to move in confined spaces. For this flight envelope insect-like flapping wings seem to be an optimal mode of flying. Investigation of the aerodynamics of flapping wing MAVs is very challenging. The problem involves complex unsteady, viscous flow (mainly laminar), with the moving wing generating vortices and interacting with them. At this early stage of research only a preliminary insight into the nature of the little known aerodynamics of MAVs has been obtained. This paper describes computational models for simulation of the controlled motion of a microelectromechanical flying insect – entomopter. The design of software simulation for entomopter flight (SSEF) is presented. In particular, we will estimate the flight control algorithms and performance for a Micromechanical Flying Insect (MFI), a 80–100 mm (wingtip-to-wingtip) device capable of sustained autonomous flight. The SSEF is an end-to-end tool composed of several modular blocks which model the wing aerodynamics and dynamics, the body dynamics, and in the future, the environment perception, control algorithms, the actuators dynamics, and the visual and inertial sensors. We present the current state of the art of its implementation, and preliminary results.

Micro-Scale Flapping Wings for the Advancement of Flying MEMS

This research effort presents conceptual micro scale air vehicles whose total dimensions are less than one millimeter. The initial effort was to advance the understanding of micro aerial vehicles at sub-millimeter dimensions by fabricating and testing micro scale flapping wings. Fabrication was accomplished using a surface micromachining process called PolyMUMPs™. Both rigid mechanical structures and biomimetic devices were designed and fabricated as part of this effort. The rigid mechanical structures focused on out of plane deflections with solid connections and assembling a multiple hinge wing structure through the aid of residual stress. These devices were actuated by double hot arm thermal actuators. The biomimetic structures derived from three different insect wings to include; the dragonfly, house fly, and butterfly were selected based off of an attribute that each insect possesses in nature. The dragonfly was chosen for its high maneuverability and hovering capabilities. The house fly wing was chosen because of its durability and the butterfly wing was chosen because of its flexibility. The fabricated wings utilize a thermal bimorph structure consisting of polysilicon and gold which allows device actuation through joule heating. The released micro wings had an initial upward deflection due to residual stress between the gold and polysilicon material layers. Joule heating, from an applied bias, forces the wing to deflect downward due to the coefficient of thermal expansion mismatch between the material layers. Each fabricated bio-wing structure was tested for deflection range as well as operating frequency. From the experimental testing of the micro scale flapping bio-wings, aerodynamic values were calculated to include; aspect ratio, reduced frequency in a hover, Reynolds number of a hovering device, drag force, and gravitational force. The research verified insect based wings on the micro scale are capable of producing the desired flapping motion

Design of a flapping mechanism for reproducing the motions at the base of a dragonfly wing

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (p. 48-49).Insect flight is being studied to aid in the development of micro-air vehicles that use the flapping wing model in an attempt to achieve the high levels of maneuverability that insects have. The flight of the dragonfly has been chosen to be modeled because of its exceptional flight capabilities. This thesis addresses the flapping mechanism designed for the root of each wing. The prototype of the mechanism, built at a scale of four times the size of a dragonfly having a wingspan of 150 mm, is able to create motions in the wing of flapping and feathering, and can vary the stroke plane. The coning angle can be set between tests. The design process began with considering two methods of actuation, a four-bar transmission mechanism used in the Micromechanical Flying Insect developed in the UC Berkeley Biomimetic Millisystem Lab, and by pivoting the wing support directly with cables or rigid links. The second design was chosen to be developed further. A functional prototype was built from acrylic and parts made using stereolithography.by Teresa Liu.S.B

Design optimization of small-scale unmanned air vehicles

Ph.DDOCTOR OF PHILOSOPH