Biomemetic Systems Biomemetics: The examination of natural systems for inspiration in engineering design. Biomemetic Systems & Analogies to Engineered Aerodynamic Systems: 1,000,000+ described species of flying insects 43,000 species of vertebrates –23,000 marine, 10,000 birds and bats, 10,000 other Evolution has conducted a multi-million year optimization experiment –Flying insects date from at least 245 MYBP –Presumably highly efficient flight systems have evolved –Despite this long optimization process diversity in flying systems still exists (after a presentation given by John B. Anders of NASA Langley, 2004.)

Biomemetic Systems Many examples of biomemetic aerodynamic systems exist, e.g. high aspect ratio wings, variable lift systems & winglets (ibid, Anders) but we have yet to include sensory considerations.

Biomemetic Sensors ( Research Topics ) Skin-like conformal sensors –Gusts are detected by sensory receptors at the base of feathers; –Triggered by local ruffling of feathers, not by distributed pressure loading of wing structure (Lincoln et al.,1998; Daniel & Combes, 2002) Hearing –Cochlea mechanics; Cilia used in detection of frequencies >15kHz with spatially distributed “transducers” that fire at ~1kHz –Bone-conduction hearing –Lateral lines/swim bladders –Echo-location Vision –Mammals typically have “stereo” vision –Insects typically have 1000’s of lenses –Optical flow for Micro-Air Vehicle (MAV) navigation concepts (relative motion of fore- ground and back-ground for depth perception while in-motion) Research topics Potential application areas James E. Hubbard Jr. et al. Stadler et al.Yost

OHC cilia: 2-6  m long 0.05  m at their base 0.2  m at their tip IHC cilia: 5-6  m long Similar diameter at base and tip. Typical nerve fire rate of 300 Hz, peak rates of 1000 Hz Cochlea/Bio-inspired Sensors

Nanowire array sensors Excited into lateral vibrations Bending stresses cause magnetization change Excitation Anodic Alumina Matrix Patterned Giant Magnetoresistance (GMR) Sensors Magnetostrictive Nanowires of Varying Lengths CiliaNanowires Cochlea/Bio-inspired Pressure Sensors

Inner Ear Transduction (after mechanical model in G. J. Borden and K. S. Harris, Physiology, Acoustics, and Perception of Speech, Williams & Wilkins Company, (1980) ) Acoustic waves induced basilar membrane motion. Relative motion of tectorial and basilar membranes induces shearing/bending of cilia. Bending of cilia triggers hair cell nerve response. Basilar membrane Tectorial membrane Relative motion induced shearing of cilia

Concept for fabrication of basilar and tectorial membrane analogs at mems scale for inducing bending of Galfenol nanowires Pressure induced bending of nanowires against the tectorial membrane will generate a magnetic field, which can be sensed through GMRs. MEMs Pressure Sensor Concept

Fluid circulation through helicotrema Hair cell section Schematic of the cross-section of the package for the Galfenol nanowire acoustic sensor Schematic of the cross-section of the human-ear cochlea PACKAGING Tectorial Membrane ( Pyrex) Basilar Membrane (Silicon Oxide) Nanowires PDMS Castor oil Δ V Nickel Flux Path GMR sensor Sound waves /