Performance comparison of three-degree-of-freedom micro-positioning platforms for perfect circular,

The micro-nano-level positioning workbench plays a crucial role in precision machining, precision measurement, microelectronics engineering, bioengineering, nanoscience, and technology fields. With its increasing importance and wide-ranging applications, the requirements for the workbench in terms of accuracy, stability, stiffness, and response have become more demanding. Compliant mechanisms, which use flexible hinges instead of traditional kinematic pairs, have emerged as a new type of transmission structure for micro-positioning platforms. These mechanisms provide advantages such as no mechanical friction or gap, high motion sensitivity, and simplicity of processing. The choice of flexible hinges is critical to the performance of compliant parallel mechanisms.

Abstract (Original):

The abstract of the original article discusses the comparison and analysis of the static and dynamic characteristics of a three-degree-of-freedom platform using different flexible hinge forms, including perfect circle, ellipse, right-angle, and triangular hinges. It highlights the differences in flexibility, motion performance, displacement sensitivity, and natural frequency among the platforms. The circular hinge platform is found to exhibit better overall performance compared to other hinge forms.

Abstract (Expanded):

In this expanded article, we aim to further discuss the influence of flexible hinge form on the performance of micro-positioning platforms. We will provide a detailed analysis of the static and dynamic characteristics of compliant parallel mechanisms utilizing different flexible hinge forms. The focus will be on the perfect circle, ellipse, right-angle, and triangular hinge platforms, comparing their flexibility, motion performance, displacement sensitivity, and natural frequency.

The compliant mechanism, with its flexible hinges, offers a promising alternative to traditional kinematic pairs. It eliminates mechanical friction and gaps, while providing a high level of motion sensitivity and simplicity of processing. The parallel structure of compliant mechanisms also enhances their precision operation and positioning capabilities, making them suitable for various applications that require high motion resolution, fast response, and compact designs.

To analyze the influence of different flexible hinge forms on the performance of micro-positioning platforms, we designed and compared four different 3-RRR compliant parallel mechanisms. These mechanisms are equipped with flexible hinges of various shapes, including perfect circle, ellipse, right-angle, and triangular.

Using finite element analysis software ANSYS, we evaluated the static and dynamic characteristics of the platforms. The analysis of flexibility, based on the comparison of compliance matrices, revealed significant differences among the hinge platforms. The right-angle hinge platform demonstrated the highest flexibility, while the triangular hinge platform exhibited the lowest flexibility. The perfect circle and ellipse hinge platforms displayed similar flexibility.

We also investigated the kinematic performance of the platforms by analyzing the Jacobian matrices. While all four platforms achieved the desired motion, their performance in different directions varied considerably. This indicates that the flexible hinge form has a significant impact on the motion performance of the compliant parallel mechanisms. Notably, the right-angle hinge platform showed a smaller rotation angle compared to the other platforms.

Furthermore, we conducted sensitivity analysis to study the influence of input displacement on output displacement. The analysis revealed differences in displacement sensitivity among the hinge platforms in all directions. The circular hinge platform exhibited higher sensitivity in all directions, indicating better overall performance.

Finally, we compared the natural frequencies of the four platforms. The right-angle hinge platform was found to have the smallest natural frequency, while the triangular hinge platform had the largest. The perfect circle and ellipse hinge platforms displayed similar natural frequencies.

In summary, our analysis highlights the significant influence of flexible hinge form on the performance of micro-positioning platforms. The choice of the hinge form affects the flexibility, motion performance, displacement sensitivity, and natural frequency of the compliant parallel mechanisms. Based on our findings, the circular hinge platform exhibited superior overall performance compared to other hinge forms.

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