A Modulated Voltage Waveform for Enhancing the Travel Range of Dielectric Elastomer Actuators

2018 ◽  
Vol 85 (11) ◽  
Author(s):  
Nitesh Arora ◽  
Pramod Kumar ◽  
M. M. Joglekar
Keyword(s):  
Material Model ◽  
Dielectric Elastomer ◽  
Electrostatic Energy ◽  
Driving Voltage ◽  
Voltage Waveform ◽  
Qualitative Comparison ◽  
Dielectric Elastomer Actuators ◽  
The Stability ◽  
High Deformability ◽  
Practical Feasibility

This paper presents a method to achieve high deformability levels in dielectric elastomer actuators (DEAs) by applying a modulated voltage waveform. The method relies on supplying the electrostatic energy during the specific phase of the oscillation cycle, resulting in the enhanced travel range at a relatively low driving voltage. We consider a standard sandwich configuration of the DE actuator with neo-Hookean material model and outline an energy-based approach for delineating the underlying principles of the proposed method. A comparison of the deformability levels achieved using the quasi-static, Heaviside step, and the modulated input waveforms is presented. Significant reduction in instability voltages together with a considerable increase in the stable actuation limit is observed in the case of the modulated voltage input. The estimates of the stability thresholds are validated by integrating the equation of motion obtained using Hamilton's principle. The effect of energy dissipation is assessed by considering variations in the quality factor. Further, a qualitative comparison with experimental observations is presented highlighting the practical feasibility of the method. This investigation can find its potential use in the design and development of DEAs subjected to a time-dependent motion.

Dynamic Actuation of Electro-Elastic Spherical Membranes Using Dielectric Elastomers

Aerospace ◽  
2005 ◽  
Author(s):  
Nakhiah Goulbourne ◽  
Eric Mockensturm ◽  
Mary Frecker
Keyword(s):  
Dynamic Response ◽  
Applied Voltage ◽  
Gas Flow ◽  
Applied Pressure ◽  
Material Model ◽  
Dielectric Elastomer ◽  
Inertial Effects ◽  
Mechanical Pressure ◽  
Material Parameters ◽  
Dielectric Elastomer Actuators

This paper presents dynamic results for spherical dielectric elastomer actuators subject to an inflating mechanical pressure and an applied voltage. Different equilibria modes arise during dynamic operation due to inertial effects. In previous work, the inertial effects have been studied for the limited case of a constant applied pressure during membrane deformation [1]. Here, novel results are presented in which the dynamic response of spherical dielectric elastomer actuators to a pressure-time loading history as well as a more realistic constant gas flow rate are considered. The results are calculated for both the damped and the zero-damped cases. The spherical membrane is assumed to follow the Mooney material model where various inflation modes arise depending on the material parameters. The range of Mooney material parameters considered, the driving pressure and the applied voltage all affect the dynamic response.

scholarly journals The role of electrostriction on the stability of dielectric elastomer actuators

2014 ◽  
Vol 51 (3-4) ◽  
pp. 848-860 ◽  
Author(s):  
Massimiliano Gei ◽  
Stefania Colonnelli ◽  
Roberta Springhetti
Keyword(s):  
Dielectric Elastomer ◽  
Dielectric Elastomer Actuators ◽  
The Stability

A Compliant Translational Mechanism Based on Dielectric Elastomer Actuators

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Chuc Huu Nguyen ◽  
Gursel Alici ◽  
Rahim Mutlu
Keyword(s):  
Position Control ◽  
Translational Motion ◽  
Minimum Energy ◽  
Dielectric Elastomer ◽  
Energy Structure ◽  
Driving Voltage ◽  
Experimental Frequency ◽  
Dielectric Elastomer Actuators ◽  
Proposed Model ◽  
Crank Mechanism

This paper reports on a linear actuation mechanism in the form of a parallel-crank mechanism (i.e., double-crank mechanism) articulated with two dielectric elastomer actuators working in parallel that are fabricated as a minimum energy structure. This structure is established by stretching a dielectric elastomer (DE) film (VHB4910) over a polyethylene terephthalate (PET) frame so that the energy released from the stretched DE film is stored in the frame as bending energy. The mechanism can output a translational motion under a driving voltage applied between two electrodes of the DE film. We have proposed visco-elastic models for the DE film and the frame of the actuator so that the mechanical properties of the actuator can more accurately be incorporated into the mechanism model. The proposed model accurately predicts the experimental frequency response of the mechanism at different voltages. In addition, an inversion-based feedforward controller was successfully implemented in order to further validate the proposed model for sensorless position control of the actuators and the parallel-crank mechanism articulated with these actuators.

An Energy-Based Approach to Extract the Dynamic Instability Parameters of Dielectric Elastomer Actuators

2014 ◽  
Vol 81 (9) ◽  
Author(s):  
M. M. Joglekar
Keyword(s):  
Electric Field ◽  
Dynamic Instability ◽  
Time History ◽  
Material Model ◽  
Dielectric Elastomer ◽  
Step Voltage ◽  
Dielectric Elastomer Actuators ◽  
Time History Response ◽  
Maximum Stretch ◽  
Static Instability

An energy-based approach is presented to extract the thresholds on the transient dynamic response of step voltage driven dielectric elastomer actuators (DEAs). The proposed approach relies on establishing the energy balance at the point of maximum stretch in an oscillation cycle followed by the application of an instability condition to extract the dynamic instability parameters. Explicit expressions are developed for the critical values of maximum stretch and the corresponding nominal electric field, thus circumventing the need to perform iterative time-integrations of the equation of motion. The underlying principles of the approach are enunciated for the neo-Hookean material model and further extended to analyze relatively complex multiparameter hyperelastic models (Mooney–Rivlin and Ogden) that are employed prevalently for investigating the behavior of DEAs. The dynamic instability parameters predicted using the energy method are validated by examining the time-history response of the actuator in the vicinity of the dynamic instability. The development of dynamic instability parameters is complemented by energy-based extraction of static instability parameters to facilitate a quick comparison between the two. It is inferred quantitatively that the nominal electric field sufficient to cause the dynamic instability and the corresponding thickness stretch is lower than those corresponding to the static instability. A set of representative case studies for multiparameter material models is presented at the end, which can be used as an input for further experimental corroboration. The results of the present investigation can find their potential use in the design of DEAs subjected to transient loading.

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