Bending mode actuator

Wang, Q., Zhang, Q., Xn, B., Lin, R. and Cross, L. (1999). Nonlinear piezoelectric behavior of ceramic bending mode actuators under strong electric fields, Journal of Applied Physics 86, 6, p. 3352. 

Figure 25.2 schematically shows the inner structure of an inkjet printer with bend mode [22] piezoelectric DOD technique. Due to the pressure generated by a voltage-pulse driven piezoelectric actuator, liquid is ejected out of small orifices... 

There are a number of commercial machines available for dynamic testing under varying temperature conditions. An actuator imposes an oscillatory (linear or angular) displacement, and typically a strain-gauge load cell measures force. Testing is frequently in bending mode, producing results that may be difficult to... 

Bending modes of the wobble motor type actuators (adapted from Watson et al., 2009)... 

Instrumentation. A cantilever with a sharp tip interacting with the surface under investigation is used. The actual bending of the cantilever is measured with a laser beam deflected from a mirror-like surface spot on the back of the cantilever towards a position-sensitive photodetector. The measured signal is used to control the piezo actuators. A constant force mode in which the cantilever-surface distance is kept at a preset interaction force and a constant height mode of scanning operation are possible. The principle of operation is schematically outlined in Fig. 7.9. 

Figure 2.2 depicts the redistribution of ions and polar fluids (water) in IPMCs under an imposed electric field. When the direct effect (actuation mode) is investigated that is, upon application of a voltage, a bending deformation is observed. One notes that ideally Q — 0 after static deformation sets in. Thus ... 

Secondly, conjugated polymers were studied as biomimetic artificial muscles. A scalable physics based electro-chemo-mechanical model was developed to connect an input voltage to bending of the material. The reduced version of the model was used to design a robust adaptive controller. Also, a nonlinear mechanical model was investigated. Furthermore, a torsional actuator was developed by depositing PPy on a tube substrate with helically wound platinum fibers. A set of experiments were conducted to confirm the torsional and other actuation modes as well as the model. 

Back to die lice bending case, in order to accommodate the vibration dynamics of the beam, we cascade G(s) to H s), as illustrated in Fig. 6. As the output of G s) represents the bending displacement (as that of/f(s) does), G s) will have a dc gain of 1. Since the actuation bandwidth of an IPMC actuator is relatively low (under 10 Hz), it often suffices to capture the mechanical dynamics G(s) with a second-order system (first vibration mode) ... 

Another mode of sensing which falls into the gravimetric category is use of the electromechanical actuator property of CPs to construct "bimetallic" type strips or sensors, whose bending indicates presence of certain analytes. This property of CPs is discussed subsequently in this book in Chapter 21, and sensors based on it are also discussed therein. 

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