Modeling and inverse compensation of dynamics of base-excited ionic polymer–metal composite sensors

Abstract

Motivated by their structural monitoring and energy harvesting applications, in this article, we study the modeling and inverse compensation of cantilevered ionic polymer-metal composite sensors that are excited at base. The proposed dynamic model is physics based, combines the vibration dynamics of a flexible beam under base excitation and the ion transport dynamics within an ionic polymer-metal composite, and incorporates the effect of a tip mass. Excellent agreement is demonstrated between the model prediction and experimental measurement in both the magnitude and the phase of the frequency response, for the frequency range of 10-150 Hz. For the purpose of real-time signal processing, we further reduce the model to finite dimension by combining techniques of Padé approximation and Taylor series expansion. For the reconstruction of the base excitation signal given the sensor output, we present an inverse compensation scheme for the reduced sensor model, where stable but noncausal inversion and leaky integration are introduced to deal with zeros that are unstable and on the imaginary axis, respectively. The effectiveness of the scheme as well as the underlying model is validated experimentally in the reconstruction of structural vibration signals, when the structure to which the ionic polymer-metal composite is attached is subjected both to periodic vibrations and to an impact.

Active Sensing Methods of Ionic Polymer Metal Composite (IPMC): Comparative Study in Frequency Domain

“…Since the discovery of IPMCs' sensing capabilities in 1992 [10], the reported studies have used black-box models [11], [12], [13], grey-box models [14], [15], [16] and white-box models 2628 CD Delft, The Netherlands A. .nl and S.H.HosseinNiaKani@tudelft.nl [17], [18], [19], [20], [21], [22], [23], [24], [25] to describe their sensing dynamics. The reported application studies have investigated exploiting them as translational [11], rotational [26], and omnidirectional [27] position sensors, velocity sensors [28], wall shear stress sensors [29], seismic sensors [30], vibration sensors [31], force sensors [32], flow sensors [33], humidity sensors [34], and wearable pulse and braille sensors [35].…”

“…Sensing with IPMCs can be realized by several means i.e. measuring voltage [36], [37], [38], [39], [40], current [37], [19], [41], [31], [25], [42], [43], charge [37], [44], [29], [45], [46], and the impedance change [47], [48].…”

Ionic polymer–metal composite applications

“…[57][58][59][60] Recent applications of IPMC sensing capabilities span the measurement of force, flow, shear loading, curvature, structural health monitoring and energy harvesting. [61][62][63][64][65][66][67][68][69] IPMCs generate charges when experiencing a mechanical load or deformation. If the polymer is not deformed, the distribution of cations inside the polymer is uniform and no output voltage is detected.…”

Micro-Machined Flow Sensors Mimicking Lateral Line Canal Neuromasts

“…The capacitive detection principle was also used to fabricate bioinspired sensors based on fish SNs that contained an SU-8 hair cell [46,62]. Some flow sensors are based on the piezo-electric or depolarization detection principle [47,[63][64][65][66]. These hair cell-inspired sensors were made from ionic polymer-metal composites (IPMCs).…”