Zeyi Wu

Bio: Zeyi Wu is an academic researcher from University of Macau. The author has contributed to research in topics: Actuator & Optimal design. The author has an hindex of 3, co-authored 7 publications receiving 79 citations.

Survey on Recent Designs of Compliant Micro-/Nano-Positioning Stages

Abstract: Micromanipulation is a hot topic due to its enabling role in various research fields. In order to perform a high precision operation at a small scale, compliant mechanisms have been proposed and applied for decades. In microscale manipulation, micro-/nano-positioning is the most fundamental operation because a precision positioning is the premise of subsequent operations. This paper is concentrated on reviewing the state-of-the-art research on complaint micro-/nano-positioning stage design in recent years. It involves the major processes and components for designing a compliant positioning stage, e.g., actuator selection, stroke amplifier design, connecting scheme of the multi-DOF stage and structure optimization. The review provides a reference to design a compliant micro-/nano-positioning stage for pertinent applications.

Design, Fabrication, and Testing of a New Compact Piezo-Driven Flexure Stage for Vertical Micro/Nanopositioning

Abstract: This paper presents the design of a new compact one-degree-of-freedom (1-DOF) compliant stage driven by a piezoelectric actuator (PEA) for micro/nanopositioning in the vertical direction. An orthogonal compound bridge-type amplifier is introduced to amplify the displacement of the PEA. It significantly reduces the height of the stage and leads to a compact design. By analytical modeling of the mechanism, the design variables are determined, which are then optimized via the multiobjective genetic algorithm based on the finite-element analysis. Simulation results show that the 1-DOF stage is able to provide the maximum displacement of $181.18~\mu \text{m}$ in theory, which is more than $12\times $ the input displacement of PEA. Payload test results indicate that the stage can support a maximum load of about 80 N. Comparison study reveals that the presented vertical positioning stage offers a more compact structure than existing ones. A prototype is fabricated for experimental studies, and the deviation between the experimental and simulation results is discussed in detail. Moreover, closed-loop performance test exhibits a resolution of 10 nm for the developed vertical positioning stage. Note to Practitioners —The motivation of this paper is to devise a compact flexure-based stage, which can be mounted on the top of an XY stage for constructing a hybrid type of XYZ stage dedicated to micro/nanopositioning applications. Such a design scheme provides a more flexible solution than serial- and parallel-kinematic designs. In order to fulfill the design requirement and to improve the compactness and output directionality of the stage, a series of design processes is conducted. The design parameters are optimized and the optimal design leads to the stage dimension of 58 mm $\times20$ mm $\times15.5$ mm (length $\times $ width $\times $ height), which offers a motion range of $97.32~\mu \text{m}$ as verified by the experimental study. In consideration of the motion range and physical size, the proposed stage offers a more compact structure than available designs. Experimental results demonstrate the fine performance of the developed prototype stage for vertical micro/nanopositioning.

Design and optimization of a compact XY parallel micro/nano-positioning stage with stacked structure

Abstract: This paper introduces the design and optimization of a new piezo-driven compact XY parallel stage for micro/nano-positioning applications The compact parallel stage is developed with a stacked design A displacement amplifier is adopted to amplify the stroke of piezo actuator The amplifier is then improved and integrated with the decoupler to isolate the two actuators The main design variables of the stage are optimized by applying a genetic algorithm based on finite-element analysis (FEA) for achieving the required performance The designed stage is then further improved to enhance the stage's performance The performance of the proposed XY precision stage is verified by performing FEA simulation studies

Design and testing of a micro-syringe pump driven by piezoelectric actuator

Abstract: In this paper, the design and testing of a micro-syringe pump is carried out for precision delivery of liquid inside a tiny tube A single-axis micro-motion pump is designed by using flexure mechanisms for precision drive of the micro-syringe Based on the required specifications of travel range and load capability, a compliant translational motion mechanism is developed The machine parameters are designed and optimized to cater for the requirement on the pump performance The performance is verified by conducting finite element analysis (FEA) simulations A prototype pump actuated by a piezoelectric stack actuator is developed, a PID feedback controller is designed, and experiment studies are undertaken for performance testing of the precision pump under a microscope

Review of Electrothermal Actuators and Applications

Abstract: This paper presents a review of electrothermal micro-actuators and applications. Electrothermal micro-actuators have been a significant research interest over the last two decades, and many different designs and applications have been investigated. The electrothermal actuation method offers several advantages when compared with the other types of actuation approaches based on electrostatic and piezoelectric principles. The electrothermal method offers flexibility in the choice of materials, low-cost fabrication, and large displacement capabilities. The three main configurations of electrothermal actuators are discussed: hot-and-cold-arm, chevron, and bimorph types as well as a few other unconventional actuation approaches. Within each type, trends are outlined from the basic concept and design modifications to applications which have been investigated in order to enhance the performance or to overcome the limitations of the previous designs. It provides a grasp of the actuation methodology, design, and fabrication, and the related performance and applications in cell manipulation, micro assembly, and mechanical testing of nanomaterials, Radio Frequency (RF) switches, and optical Micro-Electro-Mechanical Systems (MEMS).

Review on Multi-Degree-of-Freedom Piezoelectric Motion Stage

Abstract: Multi-degree-of-freedom (multi-DOF) piezoelectric motion stage is an important part of modern manufacturing industry. In order to perform high precision outputs in a large travel range, various multi-DOF piezoelectric motion stages have been proposed and applied for decades. This paper is concentrated on reviewing the research on a piezoelectric motion stage. It involves the major components, operating principles of different actuation modes, design schemes, and structures of the multi-DOF piezoelectric motion stages. In this paper, the summary and classification of the actuation modes used in the multi-DOF piezoelectric motion stages are presented, mainly including the resonance actuation mode, inertial actuation mode, clamping and feeding actuation mode, and direct actuation mode; the multi-DOF piezoelectric motion stage is divided into multi-actuator type and single-actuator type according to the number of actuators used in the motion stage, in which the multi-actuator type includes series, parallel, and series–parallel types from the viewpoint of structure mechanism; in addition, the output performances of the stages are compared, and the state of the arts of the stages are discussed and summarized; the further efforts and future research perspectives are highlighted.

A novel XYZ micro/nano positioner with an amplifier based on L-shape levers and half-bridge structure

Abstract: This paper presents the design, modeling, and experimental validation of a novel XYZ micro/nano positioner driven by piezoelectric actuator (PEA). To achieve a large motion stroke, compact structure and good decoupling performance, a novel displacement amplifier including L-shape levers and half-bridge (LSLHB) is proposed. By utilizing a concave input mechanism for location restriction between PEA and flexible mechanism, the motion coupling caused by the inconsistent central axes of the PEA and input mechanism is eliminated. The XYZ micro/nano positioner mainly consists of a parallel XY stage and a Z stage nested on the XY stage. The XY stage is constructed with four LSLHB amplifiers which are orthogonally arranged to realize X- and Y- axis motion and kinematic decoupling. The characteristics of the positioner are studied by analytical modeling and finite element analysis. The XYZ micro/nano positioner is manufactured by wire electrical discharge machining, and the performance of the positioner is evaluated through experimental tests. The results show that the stage can implement three degree-of-freedom translational motion with a workspace of 128.1 μm×131.3 μm×17.9 μm, and the coupling errors in the non-working direction is less than 1.56 % of the motion stroke, and motion resolution is 8 nm.