Micromechanical Flying Insect
Biomimetic Millisystem Lab



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Biomimetic Millisystems Lab


                            

Micromechanical Flying Insect (MFI) Project
The goal of the micromechanical flying insect (MFI) project is to develop a 25 mm (wingtip-to-wingtip) device capable of sustained autonomous flight. The MFI is designed based on biomimetic principles to capture some of the exceptional flight performance achieved by true flies. The high performance of true flies is based on large forces generated by non-steady state aerodynamics, a high power-to-weight ratio motor system, and a high-speed control system with tightly integrated visual and inertial sensors. Our design analysis shows us that piezoelectric actuators and flexible thorax structures can provide the needed power density and wing stroke, and that adequate power can be supplied by lithium batteries charged by solar cells.

The MFI project started in May 1998. In the first 3 years of this MURI grant, research concentrated on understanding fly flight aerodynamics and on analysis, design and fabrication of MFI actuators, thorax and wings. In August 2001, our MFI prototype (with 1 wing) showed thrust forces on a test stand. In September 2002, we switched our fabrication from folded stainless steel to carbon fiber. In March 2003 we demonstrated 500 microNewtons of lift from a single wing on a test stand. Since March 2003, we have been working on reducing weight, increasing actuator power density, increasing air frame strength, and improving wing control. In 2007, using higher frequency actuation, we showed thrust of 1400 microNewtons, with a test bench setup.

2002 Overview of MFI project from UCB Public Affairs office.

Currently work on MFI flight control and sensors is sponsored by NSF ``Robotic Insect Flight Stabilization Using Biomimetic Sensors'', Jan 2005-2009. NSF Disclaimer: ``This material is based upon work supported by the National Science Foundation under Grant No. IIS-IIS-0412541. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).''


Formerly sponsored by ONR MURI Biomimetic Robotics and DARPA Controlled Biological Systems Program 1998-2003.


Recent Results
High Lift with 270 Hz Wing Beat (Oct. 2007)
By increasing wing beat frequency from 170 Hz to 270 Hz, the lift force generated by a single wing increased from 500 uN to 1400 uN, more than 2X the lift required for the final 100 mg MFI to hover.
Steltz et al IROS 2007		 MFI bench top test
High Power Density Bimorph Actuator (Oct. 2007)
Dynamometer testing  shows energy delivery of 19 uJ per cycle from a 10 mg PZT bimorph actuator, with power delivery of > 450 W/kg at 270 Hz. (By comparison, the smallest motor available at 70 mg has power density < 100 W/kg).
Steltz&Fearing, IROS 2007		 piezo bimorph



2007 MFI in finger tips
Single actuator piezo amplifying thorax. E. Steltz. (2007)
  single actuator MFI 2007
Single actuator thorax with passive wing rotation. E. Steltz. (2007)

2 wing carbon fiber air frame and thorax with actuators (Dec. 2003).
Quad wing thorax and airframe, 8 actuators. Mass ~ 250 milligrams. Foam core carbon fiber. (November 2003)
Artist's drawing of future autonomous MFI, as of 2/04 (R.J. Wood/UCBerkeley).
 
Artist's conception of future MFI with optical flow sensors and radio. (Quan Gan, UC Berkeley, March 2004)

One wing MFI prototype on flight-mill test stand boom (August 2001). Movie (.avi).
One wing MFI prototype on flight-mill thrust up (March 2002). Movie (.avi).
openloop on wire test (July 2003) Movie (.mpg).
Simulation of MFI orientation recovery (1.5 MB .avi).
Old mockup of stainless steel MFI (2/01). 		Other MFI artist's conceptions, including earlier historical revisions

MFI component technologies


Bimorph piezoelectric actuator (mass 11 mg) develops 400 W/kg at 250 Hz.
Laser micromachined components for thorax structure.

Carbon fiber reinforced wing has mass less than 0.3 milligrams, and inertia of 10 mg-mm^2.
Wing motion at 150 Hz.

Dual 4 bar with spherical 5 bar differential for wing flap and rotation.
CAD model for dual 4 bar and wing differential