Citation: Wang, K.; Gao, L.; Gui, Y.;
Lu, Z.; Wang, D.; Li, J.; Wang, Q.
Bio-Inspired Mechano-Sensor Based
on the Deformation of Slit Wake.
Appl. Sci. 2022, 12, 4456. https://
doi.org/10.3390/app12094456
Academic Editors: Ki-Hyun Kim and
Deepak Kukkar
Received: 3 April 2022
Accepted: 25 April 2022
Published: 28 April 2022
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Article
Bio-Inspired Mechano-Sensor Based on the Deformation of
Slit Wake
Kejun Wang, Lei Gao, Yuecheng Gui, Zezhong Lu, Deshan Wang, Jiaqiang Li * and Qian Wang *
School of Mechanical and Electric Engineering, Soochow University, Suzhou 215021, China;
kjwang@suda.edu.cn (K.W.); 20215229100@stu.suda.edu.cn (L.G.); 20195229009@stu.suda.edu.cn (Y.G.);
20215229107@stu.suda.edu.cn (Z.L.); wangwangdeshan@163.com (D.W.)
* Correspondence: lijiq@suda.edu.cn (J.L.); qianwang@suda.edu.cn (Q.W.)
Abstract:
Internal mechano-sensors, as an indispensable part of the proprioceptive system of intelli-
gent equipment, have attracted enormous research interest because of their extremely crucial role in
monitoring machining processes, real-time diagnosis of equipment faults, adaptive motor control
and so on. The mechano-sensory structure with signal-transduction function is an important factor in
determining the sensing performance of a mechano-sensor. However, contrary to the wide application
of the cantilever beam as the sensory structure of external mechano-sensors in order to guarantee
their exteroceptive ability, there is still a lack of an effective and widely used sensory structure to
significantly improve the sensing performance of internal mechano-sensors. Here, inspired by the
scorpion using the specialized slit as the sensory structure of internal mechano-sensilla, the slit is
ingeniously used in the design of the engineered internal mechano-sensor. In order to improve the
deformability of the slit wake, the hollowed-out design around the slit tail of biological mechano-
sensilla is researched. Meanwhile, to mimic the easily deformed flexible cuticular membrane covering
the slit, the ultrathin, flexible, crack-based strain sensor is used as the sensing element to cover the
controllable slit wake. Based on the coupling deformation of the slit wake, as well as the flexible strain
sensor, the slit-based mechano-sensor shows excellent sensing performance to various mechanical
signals such as displacement and vibration signals.
Keywords: bio-inspired; slit; sensory structure; mechano-sensor
1. Introduction
Mechano-sensors are a kind of sensor that can convert a variety of mechanical sig-
nals (such as air/water flow, vibration, touch, acoustic signal, and so on) into electrical
signals [1–4]
. In the engineering field, mechano-sensors are important for engineering
equipment to detect mechanical signals in the internal and external environment, because
mechanical signals contain a lot of information for rehabilitation monitoring of advanced
equipment, guiding the control of mechanical actuators, and precise motion control of intel-
ligent robots in complex working conditions [
5
–
8
]. Recently, there has been an urgent need
to further significantly improve the sensing performance of mechano-sensors. However,
after decades of research, the mechano-sensors based on traditional design methods are
quickly approaching their performance limits. Therefore, exploring novel strategies is very
important for developing mechano-sensors with excellent performance such as ultra-high
sensitivity, low power consumption, durability, and so on.
The signal-conduction sensory structure and signal-transduction materials are two
major sensing elements of mechano-sensors [
9
–
11
]. The coupling design of the above two
elements is key to achieving the optimal performance of various mechano-sensors. Because
the mechanical signals cannot be directly received by signal-transduction materials, it
first requires a highly specialized sensory structure to achieve the efficient collection of
dispersed signals at the sites of nanoscale functional materials [
12
–
14
]. Obviously, it is one
of the necessary ways for developing next-generation mechano-sensors by designing a
Appl. Sci. 2022, 12, 4456. https://doi.org/10.3390/app12094456 https://www.mdpi.com/journal/applsci
