Design and Performance Analysis of Precision Micro-drive Amplification Mechanism

At present, there are shortcomings in the research of micro-drive amplification mechanism, such as insufficient precision and additional force. In this paper, a kind of micro-drive amplification mechanism is designed and its positioning accuracy is simulated. Firstly, a kind of micro-drive amplification mechanism is designed, which can accurately transform the input displacement of piezoelectric ceramic actuator (PZT) into the output displacement of a certain number of amplification. the theoretical motion magnification ratio of the mechanism is 3:1. Secondly, the kinematics and simulation of the mechanism were studied, and the conversion performance of the mechanism was analyzed. The results showed that the micro-drive amplification mechanism has the advantage of high positioning accuracy (maximum positioning error is 4.67%). Finally, through strength analysis and modal analysis, the performance of micro-drive amplification mechanism is studied. This study has some reference value for the research and application of precision micro-drive amplification mechanism.

Study on compliant actuator based on compliance features of flexible hinges

In order to improve the key performance of the compliant actuators, it is necessary to parametrically optimize the compliant actuators based on the compliance features of flexible hinges. A new structural parameter λ, the compliance ratio, which could reflect the sensitivity of the main form of the output displacement, was proposed and analyzed in detail. A compliant lever actuator was developed, and it was optimized by making use of the parameter λ. The optimization was also validated by finite element method (FEM) simulation and experiment. The simulation and experiment results both show that the magnification ratio of the compliant actuator could be enlarged effectively based on the compliance features of flexible hinges. Finally, an actual application of the linear positioning platform that was driven by the compliant lever actuator directly was carried out, and the experiment data also show that the platform with the optimized actuator has different degrees of optimization in terms of the key performance, including the resolution, the motion speed, and the working stroke. It is helpful to develop the compliant actuators and apply it into the precision engineering.

ANALYSIS AND OPTIMAL DESIGN THE EFFECT OF DESIGN VARIABLES ON MAGANIFICATION RATIO OF A MAGANIFICATION MACHANISM EMPLOYING FLEXIBLE HINGE

In order to high work performant for compliant mechanism about motion scope, work long term and high frequency. Therefore, in this investigation displacement, maximum principal stress and the first modal shape frequency were analyzed by Finite element analysis (FEA) for a magnification mechanism to find out effects of design variables on magnification ratio of this mechanism. The FEA outcomes indicated that design variables have significantly affected on magnification ratio, maximum principal stress and the first modal shape frequency of a magnification mechanism. The magnification ratio obtained 42.83 times thereby maximum principal stress is equal to 132.79 MPa and the first modal shape frequency is equal to 377.44 Hz, respectively. The forecast results by the Taguchi method achieve a displacement of 0.4392 mm, and according to this method the optimal structure has a displacement of 0.4451 mm with the dimensions of the following variables: variable A is 0 mm, variable B is 23 mm and C is 60 mm, the parameters combine at the levels A1B2C1. This structure amplified 44.51 times, this result is a good agreement compared with the forecast results, the error compared to the forecast is 1.33%.the forecast results, the error compared to the forecast is 1.33%.

Hydrodynamics and Free-Flow Characteristics of Piano Key Weirs with Different Plan Shapes

This paper focuses on Piano Key Weirs (PKWs) as an effective solution for improving the discharge capacity of spillway systems. The flow behavior in inlet and outlet keys is experimentally studied to analyze the discharge capacity of PKWs with different plan shapes (i.e., rectangular, trapezoidal, and triangular). The results show that in outlet keys, the flow aeration regimes extend to higher values of headwater ratios (Ho/P) by increasing the length magnification ratio (B/w) and apex width ratio (A/w). In addition, the local submergence length is a decreasing function of A/w, especially in high flow heads. While the total interference length enlarges by reducing A/w in lower Ho/P values (Ho/P < 0.5), a reverse trend is observed in higher headwater ratios. PKW performance may also be impacted by the flow contraction and recirculation zone in inlet keys, which intensify in higher values of Ho/P, B/w, and A/w. According to the obtained results, while the discharge coefficient is a decreasing function of A/w in Ho/P > 0.4, it may have a reverse trend in lower head conditions. In addition, a trapezoidal PKW has the highest discharge efficiency in a wide range of the studied domain (Ho/P > 0.25 and B/w ≥ 2). It can improve the discharge efficiency by around 5%, while its body volume is almost 7% smaller than the traditional rectangular PKW. However, for low-length and high-head conditions (B/w = 1 and Ho/P > 0.5), the efficiency a rectangular PKW exceeds that of the other shapes.

Design of a Cell Phone Lens-Based Miniature Microscope with Configurable Magnification Ratio

Application of cell-phone-based microscopes has been hindered by limitations such as inferior image quality, fixed magnification and inconvenient operation. In this paper, we propose a reverse cell phone lens-based miniature microscope with a configurable magnification ratio. By switching the objectives of three camera lens and applying the digital zooming function of the cell phone, a cell phone microscope is built with the continuously configurable magnification ratio between 0.8×–11.5×. At the same time, the miniature microscope can capture high-quality microscopic images with a maximum resolution of up to 575 lp/mm and a maximum field of view (FOV) of up to 7213 × 5443 um. Furthermore, by moving the tube lens module of the microscope out of the cell phone body, the built miniature microscope is as compact as a <20 mm side length cube, improving operational experience profoundly. The proposed scheme marks a big step forward in terms of the imaging performance and user operational convenience for cell phone microscopes.

Real-Time, Inexpensive, and Portable Measurement of Water Surface Velocity through Smartphone

The purpose of this research is to propose a real-time, inexpensive, and portable method for measuring water surface velocities, in which a particle tracking velocimetry (PTV) system is developed by using a smartphone device. The system uses the mobile camera to capture the tracer floating on the river surface, whose movement is expected to represent the velocity of the water surface. The recorded tracer images are identified from the background by using the normalized RGB color model. The magnification ratio, which transforms the distance in pixel to the real distance, is estimated by using the pre-specified mobile height from the water surface, or the characteristic length of the tracer. The proposed system is built based on the iPhone 6s device. The system is tested in two cases. One case is the artificially generated images recording the movement of table tennis, and the relative error does not exceed 3%. The other is the comparison to the velocity measured by acoustic doppler current profilers (ADCP) in the river, and the relative error is not more than 15%. Finally, the limitation of the proposed method is discussed.

Proposal of an Equal-Stiffness and Equal-Stroke 2D Micro-Positioning Platform Driven by Piezoelectric Actuators

Micro-positioning platform plays an important role in the field of precision positioning such as microelectronics, robotics and biomedicine. This paper proposes an equal-stiffness and equal-stroke 2D micro-positioning platform, which is driven by piezoelectric actuators. The overall structure of the 2D micro-positioning platform adopts a nested structure and the displacement magnification mechanism adopts two hourglass displacement magnification mechanisms. The displacement magnification ratio of the hourglass displacement magnification mechanism was studied, and its structural parameters were optimized. Static stiffness analysis and simulation analysis of the micro-positioning platform were carried out. The simulation stiffness of the micro-positioning platform in the XY direction is 46873 N/m and 46832 N/m respectively. The experimental prototype of the micro-positioning platform was built. Through the measurement experiment with the prototype, the maximum stroke of the micro-positioning platform in the XY direction is 489 μm and 493 μm respectively; the maximum coupling ratio in the XY direction is 2.38% and 2.70% respectively. The research indicates that the micro-positioning platform had the characteristics of small size, equal long stroke, equal stiffness and low coupling ratio in the XY direction.

A Novel 1-DOF Deployable Mechanism for Parabolic Cylindrical Surface Approximation

This paper presents a novel deployable mechanism for approximating the parabolic cylindrical surface. The proposed mechanism, which can deploy and fold synchronously in the radial and axial directions, is constructed by double four-bar linkages and scissor linkages. In the fully deployed configuration, the mechanism can approximate a cylindrical surface. It can also be folded compactly into a bundle. The radial and axial deployable mechanisms are described and their position kinematics are solved. A synchronous mechanism is designed to ensure the synchronous movement of the radial and axial mechanisms. Geometric parameters of the mechanism for approximating a given parabolic cylindrical surface are obtained. The magnification ratio of the designed mechanism is calculated. The best choice of actuator is determined through static-load analysis.