Modeling of photo-responsive liquid crystal elastomer actuators

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

doi:10.1016/j.ins.2021.01.009

Cited by 24 publications

(8 citation statements)

References 31 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%

See 1 more Smart Citation

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%

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Xu,

Hao,

Chen

et al. 2024

Adv Funct Materials

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“…As a key part of a light-driven robot, light-driven actuators influence the movement capability and structural design of robots [27]. According to materials, light-driven actuators include two categories: based on biological materials and based on artificial materials.…”

Section: Light-driven Actuator Of Robotsmentioning

confidence: 99%

Light-driven small-scale soft robots: material, design and control

Ma,

Zhang,

Yang

et al. 2024

Smart Mater. Struct.

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Small robots for drug transportation, environmental detection and military reconnaissance have been a popular research topic in the field of robotics. Recently, people have proposed using light-driven actuators to make flexible and remote-controllable small robots. Herein, we reviewed the research on light-driven soft robots in recent years. First, we summarized and compared the performance and fabrication method of light-driven actuators. Then, we classified and summarized the structures of robots according to their move mode. After that, we described how to control the robot. Finally, the challenges of light-driven robots are discussed.

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“…Liquid Crystal Elastomer (LCE) is a responsive material synthesized from anisotropic rod-like liquid crystal molecules and long-chain stretch polymers [ 1 , 2 , 3 , 4 , 5 , 6 ], which can respond to external stimuli, such as thermal [ 7 , 8 , 9 ], electric [ 10 , 11 ], optical [ 12 , 13 , 14 ], magnetic [ 15 ] and chemical [ 16 , 17 , 18 , 19 ] fields. LCE generally enjoys the significant advantages of quick response to deformation, deformation recoverability and noiselessness [ 20 ], and it has broad application prospects in many fields, including artificial muscles [ 21 , 22 , 23 ], microsystems and MEMS [ 24 , 25 , 26 , 27 ], actuators and sensors [ 28 , 29 , 30 , 31 , 32 , 33 ], energy harvesters [ 34 , 35 ], medical devices [ 36 , 37 ], and telescopic optical devices [ 38 , 39 ].…”

Section: Introductionmentioning

confidence: 99%

Beating of a Spherical Liquid Crystal Elastomer Balloon under Periodic Illumination

Cheng

et al. 2022

Micromachines

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Periodic excitation is a relatively simple and common active control mode. Owing to the advantages of direct access to environmental energy and controllability under periodic illumination, it enjoys broad prospects for application in soft robotics and opto-mechanical energy conversion systems. More new oscillating systems need to be excavated to meet the various application requirements. A spherical liquid crystal elastomer (LCE) balloon model driven by periodic illumination is proposed and its periodic beating is studied theoretically. Based on the existing dynamic LCE model and the ideal gas model, the governing equation of motion for the LCE balloon is established. The numerical calculations show that periodic illumination can cause periodic beating of the LCE balloon, and the beating period of the LCE balloon depends on the illumination period. For the maximum steady-state amplitude of the beating, there exists an optimum illumination period and illumination time rate. The optimal illumination period is proved to be equivalent to the natural period of balloon oscillation. The effect of system parameters on beating amplitude are also studied. The amplitude is mainly affected by light intensity, contraction coefficient, amount of gaseous substance, volume of LCE balloon, mass density, external pressure, and damping coefficient, but not the initial velocity. It is expected that the beating LCE balloon will be suitable for the design of light-powered machines including engines, prosthetic blood pumps, aircraft, and swimmers.

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Modeling of photo-responsive liquid crystal elastomer actuators

Cited by 24 publications

References 31 publications

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Viscoelastic Dynamics of Photothermal‐Responsive Liquid Crystal Elastomer Fibers

Light-driven small-scale soft robots: material, design and control

Beating of a Spherical Liquid Crystal Elastomer Balloon under Periodic Illumination

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