A compliant mechanism with variable stiffness achieved by rotary actuators and shape-memory alloy

Mekaouche, Adel; Chapelle, Frédéric; Balandraud, Xavier

doi:10.1007/s11012-018-0844-0

Cited by 10 publications

(5 citation statements)

References 52 publications

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“…SMA can be transformed from martensite to austenite by heating and cooling it. SMA has a different elastic modulus in the martensitic and austenitic states (Mekaouche et al , 2018). During the phase transition, the change of elastic modulus is approximately linear.…”

Section: Methodsmentioning

confidence: 99%

A flexible gripper with a wide-range variable stiffness structure based on shape memory alloy

Yang

et al. 2022

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Purpose Variable stiffness structure can significantly improve the interactive capabilities of grippers. Shape memory alloys have become a popular option for materials with variable stiffness structures. However, its variable stiffness range is limited by its stiffness in two phases. The purpose of this paper is to enhance the manipulation capabilities of tendon-driven flexible grippers by designing a wide-range variable stiffness structure. Design/methodology/approach Constitutive models of shape memory alloy and mechanical models are used to analyze the performance of the variable stiffness structure. A separated solution was used to combine the tendon-driven gripper and the variable stiffness structure. The feed-forward control algorithm is used to enhance the control stability of the variable stiffness structure. Findings The stiffness variable capability of the proposed variable stiffness structure is verified by experiments. The stability of the feedback control algorithm was verified by sinusoidal tracking experiments. The variable stiffness range of 8.41 times of the flexible gripper was tested experimentally. The interaction capability of the variable stiffness flexible gripper is verified by the object grasping experiments. Originality/value A new wide-range variable stiffness structure is proposed and validated. The new variable stiffness structure has a larger range of stiffness variation and better control stability. The new flexible structure can be applied to conventional grippers to help them gain stiffness variable capability and improve their interaction ability.

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Section: Methodsmentioning

confidence: 99%

A flexible gripper with a wide-range variable stiffness structure based on shape memory alloy

Yang

et al. 2022

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“…However, the behavior of an SMA depends on its forms, such as a single wire, ring, or reinforced concrete beams. Additionally, SMAs can be embedded in structures, such as manipulators with variable stiffness mechanisms [ 74 ], antagonistic actuators [ 75 , 76 , 77 , 78 ], or structures with multi-antagonistic mechanisms [ 79 ]. Moreover, these materials can be customized considering the type of application, including medical [ 5 ], robotic [ 38 ], civil engineering [ 40 ], aerospace [ 42 ], automotive [ 44 ], and other engineering [ 80 ] applications.…”

Section: Sma Forms and Ann Applicationsmentioning

confidence: 99%

Review of Neural Network Modeling of Shape Memory Alloys

Hmede

Chapelle

Lapusta

2022

Sensors

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Shape memory materials are smart materials that stand out because of several remarkable properties, including their shape memory effect. Shape memory alloys (SMAs) are largely used members of this family and have been innovatively employed in various fields, such as sensors, actuators, robotics, aerospace, civil engineering, and medicine. Many conventional, unconventional, experimental, and numerical methods have been used to study the properties of SMAs, their models, and their different applications. These materials exhibit nonlinear behavior. This fact complicates the use of traditional methods, such as the finite element method, and increases the computing time necessary to adequately model their different possible shapes and usages. Therefore, a promising solution is to develop new methodological approaches based on artificial intelligence (AI) that aims at efficient computation time and accurate results. AI has recently demonstrated some success in efficiently modeling SMA features with machine- and deep-learning methods. Notably, artificial neural networks (ANNs), a subsection of deep learning, have been applied to characterize SMAs. The present review highlights the importance of AI in SMA modeling and introduces the deep connection between ANNs and SMAs in the medical, robotic, engineering, and automation fields. After summarizing the general characteristics of ANNs and SMAs, we analyze various ANN types used for modeling the properties of SMAs according to their shapes, e.g., a wire as an actuator, a wire with a spring bias, wire systems, magnetic and porous materials, bars and rings, and reinforced concrete beams. The description focuses on the techniques used for NN architectures and learning.

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“…[15] for further information about SMAs. Figure 2-a shows the simplified state diagram of a SMA wire in tension [12,35].…”

Section: Behavior Of the Sma Wiresmentioning

confidence: 99%

“…Note that each component was calculated from a specific simulation because of the non-additivity of the effects of each force component; see Refs. [12,30] for details about the non-linearity and anisotropy of stiffness variability when SMA components are employed in a mechanism.…”

Section: Componentmentioning

confidence: 99%

See 1 more Smart Citation

Finite element analysis of a prestressed mechanism with multi-antagonistic and hysteretic SMA actuation

Boufayed¹,

Chapelle²,

Destrebecq³

et al. 2020

Meccanica

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This paper deals with the specific hysteretic effects of a multi-antagonistic shapememory alloy (SMA) actuation system in which each wire can be thermally activated individually (one or more at a time). A planar system with six SMA wires organized in a ternary rotational symmetry is studied numerically, via finite element calculation software. The objective is to analyze the functional characteristics of such mechanism, whose response during a thermal activation sequence is multi-antagonistic and hysteretic. Important points are highlighted, such as the avoidance of buckling and plasticity, the possibility of locking a configuration without energy input, and the "attraction" effect of any heating step on the following steps. The feasibility of reaching a given target in the workspace is also illustrated. Finally, the analysis shows the necessity to consider these multi-antagonistic and hysteretic aspects of the actuation in the future design and control of such type of mechanisms. The latter could be of interest as hollow shaft rotary actuators with additional (small) translation degrees of freedom in applications requiring long-term and stable positioning at ambient temperature.

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A compliant mechanism with variable stiffness achieved by rotary actuators and shape-memory alloy

Cited by 10 publications

References 52 publications

A flexible gripper with a wide-range variable stiffness structure based on shape memory alloy

A flexible gripper with a wide-range variable stiffness structure based on shape memory alloy

Review of Neural Network Modeling of Shape Memory Alloys

Finite element analysis of a prestressed mechanism with multi-antagonistic and hysteretic SMA actuation

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