Microfabrication of bio-inspired SU-8 wings and initial analyses of their aeroelastic behaviours for microrobotic insects

This paper reports our recent progresses on the micromachining and analyses of bio-inspired all polymer wings for MAV application. SU-8 wings mimicking cranefly wings were fabricated using advanced MEMS technology. Unlike insect wings using composite materials, our wings are composed of a single material (SU-8) as a preliminary mimicry. As prepared wings approach real ones in overall weight, vein pattern, flexural stiffness and in mass distribution. To pave the way for further studying the motion of complex SU-8 wings, the aeroelastic behaviours of simple SU-8 wings (plate-like structures with aspect ratios comparable to those of cranefly wings) were analyzed. The small and large displacements of SU-8 wings were investigated considering different damping mechanisms under various air pressures. An analytical model and a numerical one were established for small and large displacements of simple SU-8 wings, respectively. The simulation methods based on full transient dynamic analysis were described considering nonlinear effects due to large flexure. A final prototype was prepared by integrating an electromagnetic actuator and SU-8 wings. The main goal is to create experimental and theoretical tools to exploit resonant wing/tergum kinematics to minimize energy expenditure for hovering flight.