Positioning control of liquid crystal elastomer actuator based on double closed-loop system structure

Wu, Jundong; Wang, Yawu; Ye, Wenjun; Su, Chun‐Yi

doi:10.1016/j.conengprac.2022.105136

Cited by 5 publications

(7 citation statements)

References 36 publications

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“…First, our model accounts for the passive extension caused by external loads, a consideration often overlooked by previous position control models. [ 35–37 ] The controlled quantities ( L ( t ) in Figure 8 and θ ( t ) in Figure 9) track their corresponding targets across different loads, demonstrating the effectiveness of the PID controller design in Figure 7. However, other quantities exhibit significant variations for different loads, a phenomenon effectively captured by our consideration of passive extension.…”

Section: Resultsmentioning

confidence: 79%

“…Thirdly, our model accounts for the loading rate effect induced by the viscosity, a mechanism also often overlooked by those position control models. [ 35–37 ] F V ( t ) in the position control (subfigures d) exhibits a larger amplitude but shorter convergence time than that in the velocity control (subfigures h). This disparity arises from the different loading rates and loading durations associated with the position and velocity control.…”

Section: Resultsmentioning

confidence: 98%

“…The results demonstrate that this model can well capture the effects of external loads, temperature, and loading rates, which have been overlooked by the previous models. [ 35–37,40–42 ] Therefore, our model demonstrates the capacity to more accurately and efficiently compute the dynamics of PTR‐LCE fiber‐actuated soft robots, contributing to the design and control of these soft robots and facilitating their industrial applications.…”

Section: Discussionmentioning

confidence: 99%

“…Consequently, several studies treat LCE fibers as one-dimensional (1D) strings, a simplification consistent with our present study. Simplified models, particularly those employed in position control of isolated LCE fibers, [35][36][37] solely consider fiber deformation caused by the phase transition and overlook the LCE viscoelasticity. However, LCE fibers exhibit significant extensibility and slow relaxation with external loads, [7,38,39] making it imperative to account for fiber deformation caused by the loads.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Xu,

Hao,

Chen

et al. 2024

Adv Funct Materials

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Liquid crystal elastomers (LCEs) with photo‐responsive properties, typically driven by either photochemical or photothermal mechanisms, have found extensive applications as, for example, actuators in soft robots. However, intricate temperature‐dependent viscoelasticity of LCEs poses a challenge, leading to a notable gap in the domain of dynamic models for photothermal‐responsive LCE (PTR‐LCE) fibers. Here, a fundamental framework is proposed for accurate modeling and real‐time simulations of PTR‐LCE fiber dynamics. The PTR‐LCE fiber is described as a one‐dimensional (1D) string model that decomposes the fiber deformation into active and passive parts, which are characterized by an order parameter and a temperature‐dependent linear viscoelasticity model, respectively. Then, independent experimental measurements of model parameters are conducted, and a numerical algorithm is developed to solve the model, which is validated for convergence, time efficiency, and accuracy. Finally, the model is employed to simulate both open‐loop and Proportional‐Integral‐Derivative (PID) control of actuators made of PTR‐LCE fibers. The results confirm the advantages of this model over previous models. This work not only reveals the physical mechanisms underlying the PTR‐LCE fiber dynamic behaviors but also provides inspirations for more efficient and precise soft robotic applications.

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Section: Resultsmentioning

confidence: 79%

Section: Resultsmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Xu,

Hao,

Chen

et al. 2024

Adv Funct Materials

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“…Stronger mechanical properties enable LCE to crawl, swim, jump, and even fly, giving LCE soft robots powerful movement abilities and provide LCE actuators with a stronger load capacity and working speed. At present, the accurate deformation control of LCEs is still a problem, and it is believed that advanced control strategies [ 111 , 112 , 113 , 114 ] can solve this problem in the future, making LCEs competent for more precise work, such as surgical robots and micro/nano manipulation.…”

Section: Discussionmentioning

confidence: 99%

Photothermal-Driven Liquid Crystal Elastomers: Materials, Alignment and Applications

Zhang

Nan

et al. 2022

Molecules

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Liquid crystal elastomers (LCEs) are programmable deformable materials that can respond to physical fields such as light, heat, and electricity. Photothermal-driven LCE has the advantages of accuracy and remote control and avoids the requirement of high photon energy for photochemistry. In this review, we discuss recent advances in photothermal LCE materials and investigate methods for mechanical alignment, external field alignment, and surface-induced alignment. Advances in the synthesis and orientation of LCEs have enabled liquid crystal elastomers to meet applications in optics, robotics, and more. The review concludes with a discussion of current challenges and research opportunities.

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Near‐Infrared Light‐Driven MXene/Liquid Crystal Elastomer Bimorph Membranes for Closed‐Loop Controlled Self‐Sensing Bionic Robots

Yang,

Meng,

Zhang

et al. 2023

Advanced Science

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More recently, soft actuators have evoked great interest in the next generation of soft robots. Despite significant progress, the majority of current soft actuators suffer from the lack of real‐time sensory feedback and self‐control functions, prohibiting their effective sensing and multitasking functions. Therefore, in this work, a near‐infrared‐driven bimorph membrane, with self‐sensing and feedback loop control functions, is produced by layer by layer (LBL) assembling MXene/PDDA (PM) onto liquid crystal elastomer (LCE) film. The versatile integration strategy successfully prevents the separation issues that arise from moduli mismatch between the sensing and the actuating layers, ultimately resulting in a stable and tightly bonded interface adhesion. As a result, the resultant membrane exhibited excellent mechanical toughness (tensile strengths equal to 16.3 MPa (||)), strong actuation properties (actuation stress equal to 1.56 MPa), and stable self‐sensing (gauge factor equal to 4.72) capabilities. When applying the near‐infrared (NIR) laser control, the system can perform grasping, traction, and crawling movements. Furthermore, the wing actuation and the closed‐loop controlled motion are demonstrated in combination with the insect microcontroller unit (MCU) models. The remote precision control and the self‐sensing capabilities of the soft actuator pave a way for complex and precise task modulation in the future.

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Positioning control of liquid crystal elastomer actuator based on double closed-loop system structure

Cited by 5 publications

References 36 publications

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Photothermal-Driven Liquid Crystal Elastomers: Materials, Alignment and Applications

Near‐Infrared Light‐Driven MXene/Liquid Crystal Elastomer Bimorph Membranes for Closed‐Loop Controlled Self‐Sensing Bionic Robots

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