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In previous work we presented design and manufacturing rules for optimizing the energy density of piezoelectric bimorph actuators through the use of laser-induced melting, insulating edge coating, and features for rigid ground attachments to maximize force output, as well as a prestacked technique to enable mass customization. Here we adapt these techniques to bending actuators with four active layers, which utilize thinner material layers. This allows the use of lower operating voltages, which is important for overall power usage optimization, as typical small-scale power supplies are low-voltage and the efficiency of boost-converter and drive circuitry increases with decreasing output voltage. We show that this optimization results in a 24%-47% reduction in the weight of the required power supply (depending on the type of drive circuit used). We also present scaling arguments to determine when multi-layer actuator are preferable to thinner actuators, and show that our techniques are capable of scaling down to submg weight actuators.

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Small-scale, highly maneuverable, flapping-wing robotic insects have a wide range of applications, including exploration, environmental monitoring, search and rescue, and surveillance. For these small-scale robots, a piezoelectric cantilever actuator driven by a high voltage drive signal is a preferred actuation mechanism. The generation of this drive signal via light and efficient power electronics is critical given the limited weight budget for the flapping-wing robot. Previous work demonstrated actuator drive circuitry using discrete power transistors and passive elements. This paper presents a new design that integrates all the power FETs into a single monolithic IC, reducing the weight of the power electronics to fit within the weight budget. This design adds the capability of driving multiple outputs to accommodate recent electromechanical design advances for flying robots.

We demonstrate a battery-powered multi-chip system optimized for insect-scale flapping wing robots that meets the tight weight limit and real-time performance demands of autonomous flight. Measured results show open-loop wing flapping driven by a power electronics unit and energy efficiency improvements via hardware acceleration.