Dielectric elastomers (DEs) deform and change shape when an electric field is applied across them. They are flexible, resilient, lightweight, and durable and as such are suitable for use as soft actuators. In this paper a physics-based and control-oriented model is developed for a DE tubular actuator using a physics-lumped parameter modeling approach. The model derives from the nonlinear partial differential equations (PDE) which govern the nonlinear elasticity of the DE actuator and the ordinary differential equation (ODE) that governs the electrical dynamics of the DE actuator. With the boundary conditions for the tubular actuator, the nonlinear PDEs are numerically solved and a quasi-static nonlinear model is obtained and validated by experiments. The full nonlinear model is then linearized around an operating point with an analytically derived Hessian matrix. The analytically linearized model is validated by experiments. Proportional–Integral–Derivative (PID) and H∞ control are developed and implemented to perform position reference tracking of the DEA and the controllers’ performances are evaluated according to control energy and tracking error.
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A Physics-based and Control-oriented Model for Dielectric Elastomer Tubular Actuator
Dielectric elastomers (DEs) are electro-active polymers that deform and change their shape when an electric field is applied across them. They are used as soft actuators since they are flexible, resilient, lightweight, and durable. Many models have been proposed to describe and capture the behavior of these actuators such as circuit representation, lumped parameter modeling, and physics-based modeling. In this paper, a hybrid between the physics and lumped parameter model is presented which is used to control the actuator. The focus of this paper is on a tubular dielectric elastomer actuator (DEA). The model proposed is validated with experimental data to evaluate its approximation to the physical actuator. The physics model offers the ability to describe how the material properties and actuator's geometry affect the dynamics and behavior of the actuator under different states. The lumped parameter model accounts for physical quantities that may not be fully expressed when formulating the physics-based equations. The discussed model performance is found to have an error less than 10% for the sinusoidal signals discussed.
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- Award ID(s):
- 1747855
- NSF-PAR ID:
- 10320989
- Date Published:
- Journal Name:
- 2021 American Control Conference
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.23919/ACC50511.2021.9483321
