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Design optimization of compliant mechanisms for vibration assisted machining applications using a hybrid Six Sigma, RSM-FEM, and NSGA-II approach

Pham Huy-Tuan, Nguyen Van-Khien, Dang Quang-Khoa, Duong Thi Van Anh, Nguyen Duc-Thong, Phan Thanh-Vu

Journal of Machine Engineering

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2023

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Vol. 23, No. 2

135--158

EN

Vibration-assisted machining, a hybrid processing method, has been gaining considerable interest recently due to its advantages, such as increasing material removal rate, enhancing surface quality, reducing cutting forces and tool wear, improving tool life, or minimizing burr formation. Special equipment must be designed to integrate the additional vibration energy into the traditional system to exploit those spectacular characteristics. This paper proposes the design of a new 2-DOF high-precision compliant positioning mechanism using an optimization process combining the response surface method, finite element method, and Six Sigma analysis into a multi-objective genetic algorithm. The TOPSIS method is also used to select the best solution from the Pareto solution set. The optimum design was fabricated to assess its performance in a vibration-assisted milling experiment concerning surface roughness criteria. The results demonstrate significant enhancement in both the manufacturing criteria of surface quality and the design approach criteria since it eliminates modelling errors associated with analytical approaches during the synthesis and analysis of compliant mechanisms.

2

Numerical and Experimental Studies on 3D Printed Compliant Mechanisms in Gripper Applications

Niedziałek Piotr Wiesław, Figurski Aleksy, Kowalik Michał

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

228--244

EN

The article describes two versions of a gripper's fingers that utilize compliant revolute kinematic pairs in their operation. The goal in designing the gripper was to create a universal structure that allows for easy adjustment of torsional stiffness and maximum rotation angle as needed. Two compliant revolute joints were proposed and applied in the creation of two versions of the gripper’s fingers. In both joints, one geometric parameter was selected for variation. Finite element analysis was conducted to calculate the statics within the parameter range. Based on the calculations, stiffness charts were created as a function of parameter values. Subsequently, using 3D printing technology in resin, two gripper fingers were produced. Experimental tests were conducted on these fingers to assess their torsional stiffness. The computational and experimental results were compared. The designed fingers are best suited for pneumatic grippers. When using them, complex force control can be eliminated because the gripping force increases gradually in accordance with the compliance of the gripper, rather than abruptly. The fingers also exhibit different stiffness characteristics depending on the direction of the grip - outward or inward.

3

Flexible coupling of drive and guide elements for parallel-driven feed axes to increase dynamics and accuracy of motion

Peukert C., Merx M., Müller J., Ihlenfeldt S.

Journal of Machine Engineering

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2017

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Vol. 17, No. 2

77--89

EN

Productivity enhancement is achievable by increasing the dynamics of machines. This can be accomplished by decreasing the moving mass or by increasing the driving forces. One possibility for increasing the drive forces lies in the use of multiple parallel-acting actuators. Because of the mechanical coupling between the drives, undesirable interference of the actuators occurs. This limits the control bandwidth of the feed axis. Feed axes of machine tools are mostly equipped with linear guides fitted with rolling elements. Since they dispose of just one degree of freedom, small errors in their alignment or thermally induced errors cause constraining loads. In this paper compliant mechanisms are used to mechanically decouple the slide from the guide and drive elements. The application of flexible joints in gantry axes with linear motors and ball screws is investigated. The dynamic behaviour of the feed axis components are modelled using the Finite Element Method. By applying the modal reduction technique, the dynamic behaviour is included in an elastic multibody simulation. With the mechanical decoupling of the drive and guide elements it is possible to increase the control bandwidth of the system. Deviations in motion may also be corrected with parallel-driven feed axis by applying compliant mechanisms.

4

Design and static testing of a compact distributed-compliance gripper based on flexure motion

Hao G., Hand R. B.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 4

708--716

EN

There are precision issues with traditional rigid-body grippers due to their nature in presence of joints’ backlash and friction. This paper presents a macroscale compliant gripper to eliminate these issues for the applications in handing delicate/brittle materials such as powder granular or manipulating sub-millimetre objects such as optical fibre and micro-lens. The compliant gripper is obtained from a 2-PRRP (P: prismatic; R: revolute) kinematic mechanism, and uses distributed-compliance joints for avoiding stress-concentration and enabling large range of motion. A very compact design is achieved by using a position space principle. The compliant gripper is modelled, fabricated, followed by comprehensive testing for characterising relationships between the input displacement/force and output displacement and between the input displacement and displacement amplification ratio, and for analysing hysteresis during loading and unloading. The experimental results are compared with finite element analysis (FEA) model and linear analytical model. The testing results have suggested good performance characteristics of this compliant gripper such as a nearly linear relationship between the input and output, a nearly constant amplification ratio for closing the jaw, and negligible hysteresis error.

5

Design and application of compliant mini-grippers for handling chemicals

Lateș D., Noveanu S., Vencel C.

Archive of Mechanical Engineering

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2015

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Vol. LXII, nr 2

205--216

EN

In this paper we propose an original configuration of a compliant mini-gripper for handling chemicals. The compliant mini-gripper is 3D modeled and analyzed with finite element method. To use it in a wider range of containers designed for laboratories we made several variants of fasteners. In order to obtain a functional prototype in a scale appropriate to characterize the system, we determined the material properties of the gripper and developed an experimental stand for characterizing the system with mini-gripper. Finally, we compared the movements of the experimental grip, made according to the movement of the bellows type actuator, determined based on, analytical and numerical results.

PL

W artykule zaproponowano oryginalną konfigurację podatnego minichwytaka do przenoszenia próbek chemikaliów. Opracowano trójwymiarowy model chwytaka i zanalizowano go metodą elementów skończonych. Wykonano kilka wariantów uchwytów dostosowanych do różnych rodzajów pojemników używanych w laboratorium. By otrzymać model funkcjonalny w odpowiedniej skali do charakteryzacji systemu wyznaczono właściwości materiałów chwytaka i zbudowano stanowisko doświadczalne do badań systemu z chwytakiem. Na koniec porównano ruchy eksperymentalnego uchwytu, sterowane ruchem siłownika typu mieszkowego, które wyznaczono na podstawie wyników badań eksperymentalnych i numerycznych.

6

Material Selection of Compliant Mechanism for Vibration Isolation

Vijayan V., Karthikeyan T.

Mechanics and Mechanical Engineering

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2014

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Vol. 18, nr 2

121--134

EN

The flexible material is always absorbing some energy and reflects it. This concept was adopted from complaint mechanism principle and it was developed with the help of topology optimization technique. An innovative idea is used these principles to create a new design to absorb the vibration in the machine shop, through an innovative design model and analysis ware discussed. This paper gives a different material selection for design of compliant mechanism and also outline about the complaint mechanisms principle and shows how it is useful in mechanical field. Recently this technique is developed with the help of advanced design and also combination of some other technique. A study has been made in this for different materials.