A physics based model for twisted and coiled actuator

Abbas, Ali; Zhao, Jianguo

doi:10.1109/icra.2017.7989726

Cited by 49 publications

(15 citation statements)

References 18 publications

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“…In this work, to achieve on-demand and remote manipulation of liquid droplets, we fabricated manipulators by embedding a heterochiral twisted and coiled actuator (TCA) [18][19][20] between softer and stiffer elastomer layers (Fig. 1a-c).…”

Section: Resultsmentioning

confidence: 99%

On-demand, remote and lossless manipulation of biofluid droplets

et al. 2022

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Section: Resultsmentioning

confidence: 99%

On-demand, remote and lossless manipulation of biofluid droplets

et al. 2022

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“…Novel fabrication methods and optimal fabrication parameters have been found [18], [19]. The behavior of the actuator can be predicted using both phenomenal models and physics-based models that have been proposed [5], [20]- [23]. Considering its high non-linearity, various position controllers [21], [24]- [26] and force controllers [27] have been developed for this type of actuator.…”

Section: Introductionmentioning

confidence: 99%

Realization of a Simultaneous Position-Stiffness Controllable Antagonistic Joint Driven by Twisted-Coiled Polymer Actuators Using Model Predictive Control

et al. 2021

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Stiffness adjustability is one of the key characteristics that help humans achieve safe and reliable motions. This paper aims to realize the simultaneous position-stiffness control of an antagonistic joint driven by a type of super-coiled polymer (SCP) artificial muscles, made from a combination of Spandex and nylon fibers. A nonlinear model that can exhibit the variable stiffness characteristics of the actuator is first proposed. The model, whose parameters are identified and verified experimentally, is suitable for estimating the actuator's stiffness as a function of the length and temperature. Based on a linearized model of the antagonistic joint system, a model predictive control (MPC) is applied to control joint angle and stiffness simultaneously. By controlling both actuators' temperatures, simultaneous position-stiffness control is realized. Our contribution also includes enhancement of MPC control by incorporating time delay estimation to estimate model variations and external disturbances. The control performance is verified with both step command and sinusoidal reference with composite frequencies of 0.02Hz to 0.1Hz. Experimental results show that the system can achieve high accuracy of joint position control performance with the maximum position error of 0.42 degrees while varying joint stiffness 46.5%.

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“…It can be made by twisting and heating a nylon thread such as a fishing line. This artificial muscle actuator has been being called in a lot of names so far (fishing line artificial muscle [1], [2], coiled fishing line actuator [3], supercoiled polymer actuator [4], [5], nylon actuator [6], twisted and coiled actuator [7], twisted and coiled polymer actuator [8]- [13], etc.). In this letter, we call it TPF actuator and categorize it into two types as follows.…”

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confidence: 99%

Rotational Angle Control of a Twisted Polymeric Fiber Actuator by an Estimated Temperature Feedback

Tahara

Hayashi

Masuya

et al. 2019

IEEE Robot. Autom. Lett.

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A twisted polymeric fiber (TPF) actuator often referred to as a fishing line/sewing thread artificial muscle, is one of the soft actuators which is made by twisting and heating a nylon fishing line. There are mainly two types of the TPF actuator, one is to make a contraction motion, which is sometimes called a twisted and coiled polymeric fiber actuator, and the other is to make a rotational motion, called simply a TPF actuator. This letter focuses on the latter one and proposes an estimated temperature feedback control method to regulate a torsional angle of the TPF actuator. The TPF actuator is very lightweight and low cost, but the advantage would be lost if some external sensors, such as a thermal sensor or encoder is used. In order to control the torsional angle without the use of the external sensors, a temperature of the actuator is estimated by measuring the change in the Ohm resistance of a heater wrapping around the actuator. By feedbacking the estimated temperature, the torsional angle can be regulated indirectly. First, the two types of models are proposed. One is to derive a desired temperature of the actuator from the desired angle. The other is to estimate the actuator's temperature from a change of the resistance of the actuator's heater. Next, the temperature feedback control law is composed using these two models. Finally, experiments of the torsional angle regulation are conducted using a prototype of the actuation module, which consists of antagonistically embedded two TPF actuators to demonstrate the usefulness of the proposed controller.

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A physics based model for twisted and coiled actuator

Cited by 49 publications

References 18 publications

On-demand, remote and lossless manipulation of biofluid droplets

On-demand, remote and lossless manipulation of biofluid droplets

Realization of a Simultaneous Position-Stiffness Controllable Antagonistic Joint Driven by Twisted-Coiled Polymer Actuators Using Model Predictive Control

Rotational Angle Control of a Twisted Polymeric Fiber Actuator by an Estimated Temperature Feedback

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