12-04-2013, 04:26 PM
FLY SPY ROBOT A Bio-mimetic flying silicon microchip
FLY SPY ROBOT.doc (Size: 1.02 MB / Downloads: 48)
Abstract
This paper presents a feasibility analysis of developing an ultra-small bio-mimetic flying machine using the most advanced engineering technologies that exist today. Without regard for the cost and potential applications of such a machine, the motivation is driven entirely by a curiosity to know if it is possible to built a controllable flying machine using very leading-edge but available technologies such as MEMS, IC, and wireless technologies. Such machine would require bio-mimetic wings, since insects and bugs are the only ultra-small flying “machines” which offer clues as to how things should fly when governed by physical laws, i.e. aero-dynamic forces that dictate how things should fly according to their characteristic length scale.MEMS actuators can be made in the same scale of insect wings and “flap” at >100Hzat very low power input. This flapping frequency is within the range of wing flapping frequency of many common insects in the millimeter dimensions. Hence, in this paper we have also an idea that if a micro battery, simple CPU, wireless receiver, and MEMS actuators can all be fitted onto a Si chip of ~1mm2 area, which weight around ~1mg, which is the typical weight of millimeter scale insects, a bio-mimetic flying machine can be realized. In fact, all these requirements are realizable by many advanced engineering facilities now. our contribution towards this project is done with the help of IIT researchers.. Here we are using the chemical reaction as a source of energy to make a robot to fly(spyro).. The SPYRO is powered by a chemical reaction. A monopropellant is injected into the body, causing a chemical reaction that releases a gas. The gas pressure that builds up pushes a piston in the fuselage. This piston is connected to the pivotally coupled wings, causing them to flap rapidly. Some of the gas is exhausted through vents(holes) in the wing and can be used to change the lift on either wing so the vehicle can turn.
INTRODUCTION:-
Bio-mimetic robots have recently gained much research interest due several new technology advancements that will eventually make them functional and useful to the general public:
1) “smart materials” such as artificial muscles and PZT which will offer new alternatives for actuation of mechanical mechanisms;
2) much more precise, efficient,
and lower cost servo motors which will allow the control of robotic movements with more precision and accuracy;
3)IC chips that allow advanced control algorithms to be implemented in a much smaller footprint than 10 years ago;
4) micro/MEMS sensors that could be embedded in robotic systems with much more functionality at smaller footprint, and with lower power consumption. Research on such robots is aimed at the advancement of ordinary robots to adapt the natural environment. On the other hand, the advancement of MEMS technology has allow engineers to fabricate much smaller mechanical actuators, gears, and systems than 15 years ago. This has led to some interest for various groups world wide to develop millimeter to centimeter scale bio-mimetic robots, e.g., a bio-mimetic swimming fish or a bio-mimetic fly. Another interesting example of a bio mimetic flying robot is the flapping wing Micro Air Vehicle (MAV), which has been an exciting research topic since a few years ago . MAVs are projected to find applications in surveillance, rescue, and military missions. Currently, many researchers in both biology and engineering fields have great interest in studying the principle and mechanism on how insects fly. As noted earlier, Fearing’s team at UC Berkeley is developing a Micromechanical Flying Insect (MFI) .The MFI is a flying insect robot in centimeter scale.
FEASIBILITY STUDY ON SILICON BASED MICRO FLYING CHIP
There are different ways for an animal to fly in mid-air, China huge birds, they use
direct wing muscles to move their wings and change the flapping frequencies and fight modes (flapping or gliding).The creations of vortices by the wings allow the flying motion of birds. For small insects, their flying mechanism is different from that of large birds. They use flapping and feathering motion for flying. Since the chord Reynolds number goes down below 103 if the wing size scales down, this leads to the domination of drag force at this range compared with the viscous force in large scale. As a result, insects cannot create any vortices for flying purpose. They can only use drag force together with their flapping mechanism for flying . Before building an actual microfly, we looked to nature for inspiration to see what obvious motions must be generated to flying a millimeter scale “body” in air, e.g.,what wing-span and flapping frequencies are needed for millimeter scale insects. In nature, there are many species of birds and insects flying in air. Depending on the size of MFC we will build, we can pick up the corresponding species of insects that are approximately the same size for detailed studies on their body characteristics such as the body weight, wing area and flapping frequency.
The relationships between body mass of some insects versus their wing sizes and wing-beat frequencies are shown in Fig. 1 and Fig. 2. Various types of insects were included in the measurements. They can be biologically classified into different categories called “order” which are listed in the legend of the graphs. It can be extracted from the data in these graphs that the wing area and the wingbeat frequency scale approximately with the body mass (m) as m0.71 and m-0.24, respectively. Also, it can be found that the wing areas vary from 1mm2 to 100cm2, the wing-beat frequencies vary from 5Hz to 316Hz and the body masses vary from 0.1mg to 10g. A more detailed discussion on the biomechanics of insect flights can be found in [10]. In the next section, we will describe a thermally actuator fabricated in our lab that was tested to respond up to 200Hz input. The actuator dimension is 1mm x 100μm x 0.8μm and was fabricated on a silicon substrate.
THERMAL ACTUATORS AS MICRO FLY WINGS
In our MFC design, parylene C is used as the structural material of the chip’s wing. Also, the wing/actuator is a trilayer structure which can be thermally actuated by heating the middle platinum layer. As an input voltage is applied across the platinum heater, the whole actuator will curl up due to the difference in the coefficient of thermal expansion (CTE) of different layers. The wing is, in fact, constructed using the same process w have developed for fabricating thermally actuated polymer MEMS underwater actuators. A detailed discussion on the modeling and fabrication process of the polymer MEMS actuator can be found in [11]. A simplified version of the fabrication process is shown in Fig. 2. A fabricated sample, which has five parylene actuators, is shown in Fig. 3(a). The dimension of each actuator is 1mm x 100μm x 0.8μm and the total resistance of the actuator is ~1k. With constant input voltage of 6V (DC), the actuators can be made to curl
up to a certain deflection. By inputting a square wave signal as shown in Fig. 3(b), the actuators can oscillate and flap between the starting and ending point as shown in Fig. 4. When the input voltage is at 6V, the actuators are heated and curl up. However, if the voltage is at 0V, the actuators are allowed to cool down and return back to their original
position.
CONCEPTUAL DESIGN OF MICRO FLAPPING WINGS
Existing MAVs could provide effective aerodynamic force and torque for flying. However, the size of the ordinary MAVs could not be reduced efficiently, because the fabrication process is limited by their complicated mechanical designs. Hence, if smaller MAVs were to be built, the structural materials of the MAVs should be compatible with MEMS processes.As mentioned earlier, Miura proposed a simple structured wing which could generate enough lift for the whole flying structure [9]. Because of the laminar (layered) design, the wing is feasible to be fabricated by MEMS technology in micro scale. In this project, a similar concept is applied in the design of the MFC’s wings, i.e., essentially, we will built many “wings” to lift a micro chip. A schematic drawing of parylene C wings which will be fabricated for the flying MFCs is shown in Fig. 5.The wings will be fabricated on top of a silicon substrate. But, the final structure of the MFC will be inverted for providing lifts to the substrate. The wings can be thermal actuated by applying enough input power. The design details of a particular actuator on the MFC will be described later. In addition to Miura’s design, a grid structure will be fabricated on each wing together with the heater in order to prevent the dislocation and deformation of the thin parylene C layer when the wing strokes down.
CONCEPTUAL DESIGN OF MICRO FLYING CHIP
In this project, we will apply the concept of micro flapping wings to make a novel biomimetric MFC. A conceptual drawing of the MFC with parylene C wings is shown in Fig. 8. Integrated circuits (IC) can be potentially fabricated on the top side for control, sensing, and communication purposes. MEMS fabricated batteries have already been reported and is currently an ongoing research topic . Hence, it is possible that a battery can also be fabricated on-chip in the near future with enough energy density to fly the MFC. This on-chip battery could be attached to the bottom side of the silicon chip to provide energy for the actuating wings, ICs, wireless circuit, and sensors. However, at this stage, the flying mechanism of the MFC is the focus of our research efforts, i.e., we intend to demonstrate a flying prototype of the MFC with wires attached to it to supply power and command.
CONCLUSION
This paper proposed a novel micro flying “machine” model which could potentially perform ascending, linear movement and rotation. We call this “machine” a spyro. since will be built based on MEMS and IC technologies. A feasibility study of the flying silicon chip was carried out by studying existing flying insect data accumulated by biologists. Some of the flying insects are able to lift their body mass of 0.1 mg with wing area range from 1mm2 to 3mm2 and wing flapping frequency range form 60Hz to 177Hz. These parameters can be emulated by constructing MEMS polymer actuators in ~1mm2 area.
We hope that our idea will make this spyro to fly in the easy way rather than complicating it with using polymers or chip technology.This spyro will help in the defence field a lot there by protecting our nation from illegal immigrants.This project will be realized only there is sufficient fund is available..