Cricket Inspired Flow-Sensor Arrays (original) (raw)
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Artificial sensory hairs based on the flow sensitive receptor hairs of crickets
This paper presents the modelling, design, fabrication and characterization of flow sensors based on the wind-receptor hairs of crickets. Cricket sensory hairs are highly sensitive to drag-forces exerted on the hair shaft. Artificial sensory hairs have been realized in SU-8 on suspended Si x N y membranes. The movement of the membranes is detected capacitively. Capacitance versus voltage, frequency dependence and directional sensitivity measurements have been successfully carried out on fabricated sensor arrays, showing the viability of the concept.
Hair-Based Flow-Sensing Inspired by the Cricket Cercal System
World scientific series in nanoscience and nanotechnology, 2014
micro electro mechanical system (MEMS) offers exciting possibilities for the fabri cation of bioinspired mechanosen sors. Over the last years we have been working on cricket inspired hair-sen sor arrays for spatio-temporal flow-field observations (i.e., flow-cameras) and source locali zation. Whereas making Aow-sensors as energy efficient as cricket hair-sensors appears to be a real challenge, we have managed to fabricate hair-sensors with sub-millimeter per second flow sensing thresholds, use them in lateral line experiments, address them individually while in arrays, track transient flows, quantify viscous coupling effects and use parametric effects to achieve sharp filtering and amplification. In this research insect biologists and engineers have been working in close collaboration, generating a bidirectional flow of inforrnation and knowiedge, beneficial to both. For example where the engineer ing has greatly benefitted from the insights derived from biology and biophysical modeis, the biologists have taken advantage of MEMS structures allowing for experiments that are hard to do on living material.
MEMS based hair flow-sensors as model systems for acoustic perception studies
Arrays of MEMS fabricated flow sensors inspired by the acoustic flow-sensitive hairs found on the cerci of crickets have been designed, fabricated and characterized. The hairs consist of up to 1 mm long SU-8 structures mounted on suspended membranes with normal translational and rotational degrees of freedom. Electrodes on the membrane and on the substrate form variable capacitors, allowing for capacitive read-out. Capacitance versus voltage, frequency dependence and directional sensitivity measurements have been successfully carried out on fabricated sensor arrays, showing the viability of the concept. The sensors form a model system allowing for investigations on sensory acoustics by their arrayed nature, their adaptivity via electrostatic interaction (frequency tuning and parametric amplification) and their susceptibility to noise (stochastic resonance).
Learning from crickets: artificial hair-sensor array developments
2010 IEEE Sensors, 2010
We have successfully developed biomimetic flowsensitive hair-sensor arrays taking inspiration from mechanosensory hairs of crickets. Our current generation of sensors achieves sub mm/s threshold air-flow sensitivity for single hairs operating in a bandwidth of a few hundred Hz and is the result of a few iterations in which the natural system (i.e. crickets filiform hair based mechano-sensors) have shown ample guidance to optimization. Important clues with respect to mechanical design, aerodynamics, viscous coupling effects and canopy based signal processing have been used during the course of our research. It is only by consideration of all these effects that we now may start thinking of systems performing a "flow-camera" function as found in nature in a variety of species.
Highly-sensitive, biomimetic hair sensor arrays for sensing low-frequency air flows
TRANSDUCERS 2009 - 15th International Conference on Solid-State Sensors, Actuators and Microsystems, 2009
In this paper, we report, to the best of our knowledge [1, 2], the most sensitive artificial hair-based flowsensor arrays operating in air, to date. Artificial hair sensors are bio-inspired from the cerci of crickets, one of nature's best in sensing small air flows. The presented hair sensor arrays aim to realize comparable sensitivity to nature by means of model-based design optimizations and were fabricated using advanced MEMS technologies. The presented artificial hair sensor arrays display a clear figure-of-eight response and show remarkable sensitivities to oscillating air flows down to 0.85 mm/s surpassing noise levels at 1 kHz operational bandwidths.
Crickets as Bio-Inspiration for MEMS-Based Flow-Sensing
Flow Sensing in Air and Water, 2014
MEMS offers exciting possibilities for the fabrication of bio-inspired mechanosensors. Over the last few years, we have been working on cricketinspired hair-sensor arrays for spatio-temporal flow-field observations (i.e. flow camera) and source localisation. Whereas making flow-sensors as energy efficient as cricket hair-sensors appears to be a real challenge we have managed to fabricate capacitively interrogated sensors with sub-millimeter per second flow sensing thresholds, to use them in lateral line experiments, address them individually while in arrays, track transient flows, and use non-linear effects to achieve parametric filtering and amplification. In this research, insect biologists and engineers have been working in close collaboration, generating a bidirectional flow of information and knowledge, beneficial to both, for example, where the engineering has greatly benefitted from the insights derived from biology and biophysical models, the biologists have taken advantage of MEMS structures allowing for experiments that are hard to do on living material.
Biomimetic flow sensors for environmental awareness
The Journal of the Acoustical Society of America, 2013
ABSTRACT Crickets possess hairy organs attached to their abdomen, the so-called cerci. These cerci contain highly flow-sensitive mechanosensors that enable the crickets to monitor the flow-field around them and react to specific stimuli form the environment, e.g., air-movements generated by hunting spiders. Salient is the sensitivity of these sensors, which work at thermal noise threshold levels, and the large number of hairs which, together with the necessary neural processing, allows the cricket to use the cerci as a kind of "flow-camera." Biologists and engineers have been working together in the recent past to regenerate part of the outstanding sensing capabilities of crickets in manmade, bio-inspired flow-sensor arrays. Using micro-electromechanical systems (MEMS) technology, sensors are created that are sensitive and show a high degree of directivity. By analyzing the governing physics, the sensors have been optimized to the point that currently the electronic interfacing is the limiting factor. Nonlinear parametric effects are used to increase the range of applicability of the sensors. Stochastic resonance is investigated to further enhance sensing capabilities. Arrays of sensors, interfaced using frequency division multiplexing (FDM), have been demonstrated to enable the tracking of the movement of small spheres.
Interfacing of differential-capacitive biomimetic hair flow-sensors for optimal sensitivity
Biologically inspired sensor-designs are investigated as a possible path to surpass the performance of more traditionally engineered designs. Inspired by crickets, artificial hair sensors have shown the ability to detect minute flow signals. This paper addresses developments in the design, fabrication, interfacing and characterization of biomimetic hair flow-sensors towards sensitive high-density arrays. Improvement of the electrode design of the hair sensors has resulted in a reduction of the smallest hair movements that can be measured. In comparison to the arrayed hairs-sensor design, the detection-limit was arguably improved at least twelve-fold, down to 1 mm s -1 airflow amplitude at 250 Hz as measured in a bandwidth of 3 kHz. The directivity pattern closely resembles a figure-of-eight. These sensitive hair-sensors open possibilities for high-resolution spatio-temporal flow pattern observations.
Hair sensors for oscillatory airflow, operating in the regime of bulk flow, particle velocity or both, can be characterized by several methods. In this work, we discuss harmonic measurements on MEMS hair flow sensors. To characterize this type of flow sensor the use of three different types of oscillatory airflow source is investigated. A loudspeaker, a vibrating sphere and a standing wave tube all have specific characteristics regarding their acoustic field, frequency range, maximum velocity amplitude and the possibility to chose the ratio between pressure and flow velocity. They are compared and an overview is given with respect to which source is the most appropriate under specific conditions. Furthermore, by combining information from the flow setups used new insights into sensor operation can be gained.
Insect-Inspired Distributed Flow-Sensing: Fluid-Mediated Coupling Between Sensors
Architectured Materials in Nature and Engineering, 2019
Crickets and other arthropods are evolved with numerous flow-sensitive hairs on their body. These sensory hairs have garnered interest among scientists resulting in the development of bio-inspired artificial hair-shaped flow sensors. Flow-sensitive hairs are arranged in dense arrays, both in natural and bio-inspired cases. Do the hair-sensors which occur in closely-packed settings affect each other's performance by so-called viscous coupling? Answering this question is key to the optimal arrangement of hair-sensors for future applications. In this work viscous coupling is investigated from two angles. First, what does the existence of many hairs at close mutual distance mean for the flow profiles? How is the air-flow around a hair changed by it's neighbours proximity? Secondly, in what way do the incurred differences in air-flow profile alter the drag-torque on the hairs and their subsequent rotations? The first question is attacked both from a theoretical approach as well as by experimental investigations using particle image velocimetry to observe air flow profiles around regular arrays of millimeter sized micro-machined pillar structures. Both approaches confirm significant reductions in flow-velocity for high density hair arrays in dependence of air-flow frequency. For the second set of questions we used dedicated micro-fabricated chips consisting of artificial hair-sensors to controllably and reliably investigate viscous coupling effects between hairsensors. The experimental results confirm the presence of coupling effects (including secondary) between hairsensors when placed at inter-hair distances of less than 10 hair diameters (d). Moreover, these results give a thorough insight into viscous coupling effects. Insight which can be used equally well to further our understanding of the biological implications of high density arrays as well as have a better base for the design of biomimetic artificial hair-sensor arrays where spatial resolution needs to be balanced by sufficiently mutually decoupled hair-sensor responses †.