Design and Modeling of a Curved Beam Compliant Mechanism with Six Degrees of Freedom

Lin, Sheng; Wang, Jiacheng; Xiong, Wenkang; Hu, Qingyuan; Liu, Hui; Wang, Qi

doi:10.3390/mi13020208

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…In the last two decades, compliant mechanisms [1][2][3] have produced a growing interest in academic and industrial fields [4,5]. These types of mechanisms manifest their motion through the deformation of some very slender parts [6][7][8] instead of kinematic pairs. Compliant mechanisms have some advantages when compared to lumped pairs: they do not require lubrication or maintenance as they have a monolithic form (directly replaceable if failure occurs); can be made via low-cost additive manufacturing; are not affected by clearance, friction and wear on contacting parts; and they can be very light.…”

Section: Introductionmentioning

confidence: 99%

Elasto-Kinematics and Instantaneous Invariants of Compliant Mechanisms Based on Flexure Hinges

Iandiorio

Salvini

2023

Micromachines

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The kinematic synthesis of compliant mechanisms based on flexure hinges is not an easy task. A commonly used method is the equivalent rigid model, which involves replacing the flexure hinges with rigid bars connected with lumped hinges using the already known methods of synthesis. This way, albeit simpler, hides some interesting issues. This paper addresses the elasto-kinematics and instantaneous invariants of flexure hinges with a direct approach, making use of a nonlinear model to predict their behaviour. The differential equations that govern the nonlinear geometric response are given in a comprehensive form and are solved for flexure hinges with constant sections. The solution to the nonlinear model is then used to obtain an analytical description of two instantaneous invariants: the centre of instantaneous rotation (c.i.r.) and the inflection circle. The main result is that the c.i.r. evolution, namely the fixed polode, is not conservative but is loading-path dependent. Consequently, all other instantaneous invariants are loading-path dependent, and the property of instantaneous geometric invariants (independent of the motion time law) can no longer be used. This result is analytically and numerically evidenced. In other words, it is shown that a careful kinematic synthesis of compliant mechanisms cannot be addressed by only considering the kinematics as rigid mechanisms, and it is essential to take into consideration the applied loads and their histories.

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Section: Introductionmentioning

confidence: 99%

Elasto-Kinematics and Instantaneous Invariants of Compliant Mechanisms Based on Flexure Hinges

Iandiorio

Salvini

2023

Micromachines

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“…Electro motors, piezoelectrics, and shape memory alloys (SMAs) are the most commonly utilised actuator types to achieve precise motion in such systems. Extensive investigations have been conducted on piezoelectric-driven systems to showcase the capabilities of this material as an actuator for compliant mechanisms [1][2][3]. While piezoelectric materials offer advantages such as rapid response and accurate motion, they are limited by a relatively small range of motion compared to their size.…”

Section: Introductionmentioning

confidence: 99%

Mathematical modelling and experimental study of a novel planar micro-positioning stage using shape memory alloy actuators

Rahbari,

Fathi,

Dardel

2023

Smart Mater. Struct.

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The application of smart materials as actuators in precise positioning systems has witnessed significant growth in recent years. However, the use of Shape Memory Alloy Materials (SMAs) in this context is hindered by their slow response and complex nonlinear behaviour. To overcome these limitations, this paper introduces a novel approach that incorporates two opposite SMA actuators into a flexure hinge type micro-positioning stage, aiming to enhance the system speed. A semi-analytical modelling approach is employed to model the nonlinear behaviour of the SMA actuator. Using the available material models for SMA materials and the nonlinear curved beam theory, the governing equations of the proposed SMA actuator are derived and the resulted partial differential equations are reduced to an algebraic equation based on the Galerkin method. The resulting equations are then solved using the return map method. To validate the accuracy and effectiveness of the proposed model, an experimental setup is constructed. The experimental results demonstrate the model ability to accurately predict the behaviour of the system. Additionally, the developed model allows for the extraction of stress and strain profiles of the SMA actuators for designing the actuator. The study highlights the potential of integrating the proposed model with robust control methods for future works, aiming to effectively control micro-positioning systems and further enhance their performance.

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“…Many design methods have been developed for synthesizing CPMs with various degrees of freedom (DoFs) and in different applications, i.e., 1 DoF [9,10] for grippers, 2 DoFs [11,12] for X-Y positioning stages, and 3 to 6 DoFs [13][14][15][16][17][18][19][20] for spatial motion. It is noted that CPMs with 1, 2, 3, and 6 DoFs are more widely developed than those with 4 or 5 DoFs, due to difficulties in the synthesis process.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Compliant Parallel Mechanisms Using an Improved Beam-Based Method with the Optimization of Multiple Resonant Modes

2023

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This paper proposes an improved beam-based method to synthesize a compliant parallel mechanism (CPM) with multiple degrees of freedom (DoFs). The proposed method utilizes a structural optimization technique to synthesize a three-legged CPM with a single-beam structure constructed by two perpendicular segments in each leg to achieve the desired DoFs and fully decoupled motion. In addition, an objective function is proposed to optimize the primary resonant frequencies in actuating directions to targeted values to achieve the desired dynamic behaviors. A 4-DoF CPM, with one translation and three rotations, is synthesized using the improved beam-based method and all of the primary resonant frequencies are optimized to the targeted values. The 4-DoF CPM prototype is fabricated monolithically and evaluated experimentally in terms of its mechanical characteristics, workspace, and resonant modes. The obtained results show that the experimental stiffness and dynamic properties agree with the predictions. In particular, the prototype has good motion decoupling capability, as reflected by the high stiffness ratios of more than 500 between the non-actuating and actuating directions; the large workspaces of up to 4.0 mm and 7.2° for the translation and rotations, respectively; and the resonant frequencies being close to the targeted ones. In addition, the highest deviations between the predicted and experimental results are 9.49% and 9.13% for the stiffness and dynamic behaviors, respectively, demonstrating the correctness and effectiveness of the proposed method.

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Design and Modeling of a Curved Beam Compliant Mechanism with Six Degrees of Freedom

Cited by 7 publications

References 31 publications

Elasto-Kinematics and Instantaneous Invariants of Compliant Mechanisms Based on Flexure Hinges

Elasto-Kinematics and Instantaneous Invariants of Compliant Mechanisms Based on Flexure Hinges

Mathematical modelling and experimental study of a novel planar micro-positioning stage using shape memory alloy actuators

Synthesis of Compliant Parallel Mechanisms Using an Improved Beam-Based Method with the Optimization of Multiple Resonant Modes

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