Design of a 3DOF XYZ Bi-Directional Motion Platform Based on Z-Shaped Flexure Hinges

This paper presents a design of a 3DOF XYZ bi-directional motion platform based on Z-shaped flexure hinges. In the presented platform, bridge-type mechanisms and Z-shaped flexure hinges are adopted to amplify its output displacement. Bi-direction motion along the X-axis and Y-axis follows the famous differential moving principle DMP, and the bi-directional motion along the Z-axis is realized by using the reverse arrangement of the Z-shaped flexure hinges along the X-axis and Y-axis. Statics analysis of the proposed platform is carried out by the energy method, compliance matrix method, and force balance principle. Meanwhile, the Lagrange method is used to analyze the dynamics of the platform. A series of simulations are conducted to demonstrate the effectiveness of the proposed design. The simulation results show that the average displacements of the platform in the XYZ-axis are ±125.58 μm, ±126.37 μm and ±568.45 μm, respectively.

Design and Analysis of a Stepping Piezoelectric Actuator Free of Backward Motion

Although the stick-slip principle has been widely employed for designing piezoelectric actuators, there still exits an intrinsic drawback, i.e., the backward motion, which significantly affects its output performances and applications. By analyzing the generation mechanism of backward motion in stick-slip piezoelectric actuators, the elliptical trajectory was employed to design a novel stepping piezoelectric actuator free of backward motion. Accordingly, a prototype of piezoelectric actuator was designed, which utilized a flexure hinge mechanism and two vertically arranged piezoelectric stacks to generate the required elliptical trajectory. The compliance matrix method was used to theoretically analyze the flexure hinge mechanism. The theoretical and measured elliptical trajectories under various phase differences were compared, and the phase difference of 45° was selected accordingly. Under a critical relative gap, output performances of the actuator working under the elliptical trajectory were characterized, and then compared with that obtained under the normal stick-slip driving principle. Experimental results indicated that forward and reverse stepping displacement with completely suppressed backward motion could be achieved when employing the elliptical trajectory, verifying its feasibility. This study provides a new strategy for designing a stepping piezoelectric actuator free of backward motion.

Design and Analysis of Flexible Continuum Robot Based on Origami and Mortise-Tenon Structure (FCRBOM)

The continuum robot is a soft robot with infinite degrees of freedom. Origami has a high capacity for spatial deployment. This paper proposes a flexible continuum robot based on origami and mortise-tenon structure (FCRBOM). The robot consists of some flexible hinges based on origami and mortise-tenon structure (FHBOM). The design process of the FCRBOM is given. The compliance of the FCRBOM is analyzed by the compliance matrix method. The Finite element analysis (FEA) is used to simulate and analyze the FCRBOM, and the correctness of the theoretical analysis is verified. Then a spatial FCRBOM (SFCRBOM) is designed. The impact of key dimensional parameters on the flexibility of SFCRBOM is discussed. Finally, an SFCRBOM with higher flexibility is presented.

Design and Analysis of a Novel Flexure-Based XY Micropositioning Stage

Flexure-based micropositioning stages with high positioning precision are really attractive. This paper reports the design and analysis processes of a two-degree-of-freedom (2-DOF) flexure-based XY micropositioning stage driven by piezoelectric actuators to improve the positioning accuracy and motion performance. First, the structure of the stage was proposed, which was based on rectangular flexure hinges and piezoelectric actuators (PZT) that were arranged symmetrically to realize XY motion. Then, analytical models describing the output stiffness in the XY directions of the stage were established using the compliance matrix method. The finite element analysis method (FEA) was used to validate the analytical models and analyze the static characteristics and the natural frequency of the stage simultaneously. Furthermore, a prototype of the micropositioning stage was fabricated for the performance tests. The output response performance of the stage without an end load was tested using different input signals. The results indicated that the stage had a single direction amplification capability, low hysteresis, and a wide positioning space. The conclusion was that the proposed stage possessed an ideal positioning property and could be well applied to the positioning system.

Stiffness analysis of corrugated flexure beam using stiffness matrix method

Precision positioning techniques present a significant opportunity to support the instrumentation development for state-of-the-art micro-positioning research. The requirement of large stroke and high resolution of the mechanism without a need for amplifier mechanisms is universally recognized. Corrugated flexure beam can have some potential if designed right because of its large flexibility obtained from longer overall length on the same span. This paper presents stiffness analysis of corrugated flexure beam using stiffness or compliance matrix method. Based on Euler–Bernoulli beam theory and Mohr’s integral method, the deformation analyses of straight segment and semi-circle segment are presented. And the stiffness matrix of corrugated flexure unit is then obtained via transformation matrix. By combining the stiffness matrix of every single corrugated flexure unit, the stiffness matrix of corrugated flexure beam is delivered, which reflects the relationship between the load and displacement. The analytical models are verified by taking advantage of the finite element method, which shows that all the results can be of considerable use in the design of corrugated flexure beam.

Kinetostatics Modeling and Decoupling Analysis of a Crosshair Flexures-Based Nanopositioner

In the present paper, we take the input and output decoupling into account and propose a 2-DOF parallel nanopositioner, which is composed of lever amplification mechanisms, compound parallelogram mechanisms and novel crosshair flexures. In order to demonstrate the decoupling performance improvement of the crosshair flexures, the stiffness model of the crosshair flexures and the kinetostatics model of the nanopositioner are established based on Castigliano’s theorem and the compliance matrix method. Accordingly, the input and output decoupling compliance matrix models are derived to demonstrate the excellent decoupling property of the crosshair flexures based nanopositioner, which is further verified by finite-element analysis and experimental results. The open-loop experiments on the prototype stage demonstrate the maximum stroke of the nanopositioner is up to 65μm and the cross axis coupling errors are less than 1.6%.

Design and Assessment of a Flexure-Based 2-DOF Micromanipulator for Automatic Cell Micro-Injection

The design and assessment of a flexure-based parallel micromanipulator with two-degrees-of-freedom (2-DOF) for automatic cell injection is presented in this paper. The design and modeling of the micromanipulator are conducted by employing compliance matrix method. The dynamic modeling and analysis via Lagrange equation are conducted to improve the bandwidth of the mechanism. Both theoretical analysis and finite element analysis (FEA) results well validate the good performance of the micromanipulator which will be applied to practical cell manipulations.