Robust Adaptive Control of Conjugated Polymer Actuators

Yang, Fang; Tan, Xiaobo; Alici, Gürsel

doi:10.1109/tcst.2007.912112

Cited by 82 publications

(40 citation statements)

References 29 publications

(52 reference statements)

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“…Some studies in engineering define control effort simply as a signal in time. Examples are output signal voltage of a controller [14,37], motor armature voltage [63], actuation voltage in polymer actuators [9], or pressure in pneumatic actuators [29]. In a similar way, muscle electromyography (EMG) signal is associated with control effort in a neurological feedback control model [30].…”

Section: Introductionmentioning

confidence: 99%

Quantifying control effort of biological and technical movements: An information-entropy-based approach

et al. 2014

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In biomechanics and biorobotics, muscles are often associated with reduced movement control effort and simplified control compared to technical actuators. This is based on evidence that the nonlinear muscle properties positively influence movement control. It is, however, open how to quantify the simplicity aspect of control effort and compare it between systems. Physical measures, such as energy consumption, stability, or jerk, have already been applied to compare biological and technical systems. Here a physical measure of control effort based on information entropy is presented. The idea is that control is simpler if a specific movement is generated with less processed sensor information, depending on the control scheme and the physical properties of the systems being compared. By calculating the Shannon information entropy of all sensor signals required for control, an information cost function can be formulated allowing the comparison of models of biological and technical control systems. Exemplarily applied to (bio-)mechanical models of hopping, the method reveals that the required information for generating hopping with a muscle driven by a simple reflex control scheme is only I=32 bits versus I=660 bits with a DC motor and a proportional differential controller. This approach to quantifying control effort captures the simplicity of a control scheme and can be used to compare completely different actuators and control approaches.

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Section: Introductionmentioning

confidence: 99%

Quantifying control effort of biological and technical movements: An information-entropy-based approach

et al. 2014

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“…What is important, however, is the general idea of how one might capture the temperature-dependent behavior based on the measurements at a few sampled temperatures and how such a model can be used for developing the open-loop controller. Such an approach can be readily extended to the modeling and control of other electroactive polymer materials [60] in the presence of thermal fluctuations.…”

Section: Resultsmentioning

confidence: 99%

Modeling and open-loop control of IPMC actuators under changing ambient temperature

Dong

Tan

2012

Smart Mater. Struct.

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Because of the cost and complexity associated with sensory feedback, open-loop control of ionic polymer-metal composite (IPMC) actuators is of interest in many biomedical and robotic applications. However, the performance of an open-loop controller is sensitive to the change in IPMC dynamics, which is influenced heavily by ambient environmental conditions including the temperature. In this paper we propose a novel approach to the modeling and open-loop control of temperature-dependent IPMC actuation dynamics. An IPMC actuator is modeled empirically with a transfer function, the zeros and poles of which are functions of the temperature. With auxiliary temperature measurement, open-loop control is realized by inverting the model at the current ambient temperature. We use a stable but noncausal algorithm to deal with non-minimum-phase zeros in the system that would prevent directly inverting the dynamics. Experimental results are presented to show the effectiveness of the proposed approach in open-loop tracking control of IPMC actuators.

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“…Conjugated polymer actuators have numerous potential applications, such as microfluidic pumps [12], blood vessel connectors [13], and microvalves for flow control [14]. Different configurations of actuators have been exploited for these applications, e.g., bilayer benders [1], trilayer benders [15,16], and linear extenders [7,10].…”

Section: Introductionmentioning

confidence: 99%

“…where d = dr e r + r dθ e θ + dς e ς , dX = dx e x + dy e y + dz e z .From(14)-(16), the deformation gradient is written as F = dr dx e r ⊗ e x + r αe θ ⊗ e y + e ς ⊗ e z…”

mentioning

confidence: 99%

Nonlinear elastic modeling of differential expansion in trilayer conjugated polymer actuators

Yang¹,

Pence²,

Tan³

2008

Smart Mater. Struct.

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Conjugated polymers are promising actuation materials for biomimetic robots and biomedical devices. Large bending is involved in some of these applications. This poses significant challenges in electromechanical modeling, because the linear elasticity theory is only valid when the strain is small. In this paper an effective strategy based on the nonlinear elasticity theory is proposed to model the mechanical output of a trilayer conjugated polymer beam under actuation. Instead of using the elastic modulus as in the linear elasticity theory, we use a nonlinear strain energy function to capture the stored elastic energy under actuation-induced swelling, which further allows us to compute the induced stress. The deformation variables are obtained by numerically solving the force and bending moment balance equations simultaneously. Experimental results have demonstrated that the proposed model shows superiority over the linear model, and is able to capture the actuation behavior well under large actuation voltages. The proposed framework can also be applied to the analysis of large deformations in some other electroactive polymers.

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Robust Adaptive Control of Conjugated Polymer Actuators

Cited by 82 publications

References 29 publications

Quantifying control effort of biological and technical movements: An information-entropy-based approach

Quantifying control effort of biological and technical movements: An information-entropy-based approach

Modeling and open-loop control of IPMC actuators under changing ambient temperature

Nonlinear elastic modeling of differential expansion in trilayer conjugated polymer actuators

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