Phase II Final Report - NASA's Institute for Advanced Concepts

Planetary Exploration Using Biomimetics
An Entomopter for Flight on Mars
GTRI has designed and built a mesoscaled ultrasonic ranging transmitter for use on the terrestrial
Entomopter, and has performed sound pressure level measurements at reciprocating chemical
muscle waste gas pressures in the range of 40 psi. These tests have shown that sensible
ranges of three meters are attainable, with greater ranges possible. (See sound pressure levels of
Figure 4-3.) Emission patterns have been plotted to show that a directional beam can be created,
and an acoustic mirror scheme has been designed into the Entomopter which is capable of scanning
the output from a single ultrasonic source ranging from right-horizontal, to head-on, to
downlooking (altimetry), to head-on, to left-horizontal on each wing beat. All of these features
of the terrestrial Entomopter are transferable to the Mars version.
Figure 4-3: Multiplexing of Waste Gas-driven FMCW Ultrasonic Acoustic Ranging Source
The acoustic ranging concept would also be useful during landing in order to give higher resolution
short range position updates at a high rate.
Another passive approach would be to observe the optical flow field as the Entomopter
approaches either the planet surface or the landing deck on the rover. This is a biologicallyinspired
approach derived from analysis of honey bees and other insects. Although most insects
lack stereo vision, distances to objects are gauged in terms of the apparent speeds of motion of
the objects' images. Bees distinguish the presence of objects by sensing the apparent relative
motion at the boundary between the object and its background. As demonstrated by research at
the Australian National University, even narrow openings are negotiated by balancing the apparent
speeds of the images in the two eyes (passive detection). Flight speed is regulated by holding
230
Phase II Final Report