A Research on Ultra Precision Machining for Ti-6AL-4V Alloy Based Biomedical Applications Using Nanopositioning Mechanism

In this study, piezoelectric actuator, flexure guide, power transmission element and control method are considered for nanopositioning system apparatus. The main objectives of this thesis were to develop 2-axis nanostage which enables 2-axis control with the aid of piezoelectric actuator, and to improve the precision of the ultra-precision lathe (UP2) which is responsible for the ductile mode machining of the hardened-brittle material where the machining uses a the single-crystal diamond. Through simulation and experiments on ultra-precision positioning, stability and priority of the nanopositioning system with 2-axis nanostage and control algorithm are developed using Matlab/Simulink. Then the system, is applied to analyze surface morphology of the titanium alloy (Ti-6Al-4V)

Design of a Compact 3-DOF In-Plane Motion Stage

This paper presents the design of a new compact three-axis in-plane motion stage which work directions are X, Y, θz. The proposed stage consists of four amplification flexure structures and four piezoelectric actuators. The amplification structure uses bridge type amplification mechanism and notch type flexure guide hinge. The size of the stage is 150×150×30mm3 and has 50×50mm2 hollow in the center of the stage.

Large Scanning Range and Rapid AFM for Biological Cell Topography Imaging

The small spatial displacement of the piezo tube scanner limits the AFM(Atomic Force Microscopy) scanning range, especially when facing up to cell topography scanning. And the low dynamic property of normal AFM tube scanner tube restricts the imaging speed. In order to achieve large scanning range and rapid scanning motion simultaneously, a special atomic force microscopy is designed. The 100um scanning range is obtained by the new scanner which is composed of the flexure guide structure instead of peizo tube. Furthermore, a new acquiring image method is used to eliminating AFM nonlinearity error. Using this scanning system, some large biological cells are imaged in liquid environments with 30 lines per second.

Design, Fabrication, and Characterization of a Pneumatic Micro Actuator

Compact high force linear displacement pneumatic microactuators are useful in several applications including robotic systems, surgical micro-grippers, micro mechanisms, and so on. This paper presents development of a general purpose bellow type microactuator using silicon as structural material with a low stiffness double parallelogram flexure guides for a planar bellow piston. Double flexure mechanism achieves frictionless guiding in a perfect straight line of the actuator. The proposed design is different as compared to similar other designs in the literature in that the new design proposes a flexure guide for piston. Moreover, it is integrated with comb drive for servo actuation and is five times smaller. The actuators are fabricated using standard SOIMUMPs process and are further characterized. Actuation pressure, displacement and blocking force are measured which further demonstrates their performance in comparison with simulation results. Finally, as an application example micro-flexural logic device viz. NOT gate, actuated using the micro-pneumatic actuator is presented.

Design of a Micropositioning Table for Active Grinding Control

In order to realize active grinding control, a nanometer micropositioning table is designed. The table has a circular working area with diameter of 150 mm. Three piezoelectric actuators are utilized in parallel to drive the moving part with flexure guide mechanism. Through cooperation of the three piezoelectric actuators, the moving part can implement 3-DOF nanometer positioning. The flexure hinge mechanism can also provide preload for the actuators. The preload can keep the moving part from separation with the piezoelectric actuators during moving process. The dynamic model of the micropositioning table is developed with consideration of the driving circuit. To improve the dynamic performance of the micropositioning table, a decoupling PID controller is designed by use of frequency domain approach. The experimental tests have been carried out to verify the performance of the micropositioning table and the established decoupling controller.