In this paper, a concept of totally decoupling is proposed for the design of a flexure parallel micromanipulator with both input and output decoupling. Based on flexure hinges, the design procedure for an XY totally decoupled parallel stage (TDPS) is presented, which is featured with decoupled actuation and decoupled output motion as well. By employing (double) compound parallelogram flexures and a compact displacement amplifier, a class of novel XY TDPS with simple and symmetric structures are enumerated, and one example is chosen for further analysis. The kinematic and dynamic modeling of the manipulator are conducted by resorting to compliance and stiffness analysis based on the matrix method, which are validated by finite-element analysis (FEA). In view of predefined performance constraints, the dimension optimization is carried out by means of particle swarm optimization, and a prototype of the optimized stage is fabricated for performance tests. Both FEA and experimental studies well validate the decoupling property of the XY stage that is expected to be adopted into micro-/nanoscale manipulations.

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Design and Analysis of a Totally Decoupled Flexure-Based XY Parallel Micromanipulator

A flow control apparatus (800) includes a tubular member (818) having a plurality of openings (820, 822, 824, 826) that allow fluid flow between an exterior and an interior flow path (828) of the tubular member (818) and a multi-stage flow restricting section (804) operably positioned in a fluid flow path between a fluid source disposed exteriorly of the tubular member (818) and the interior flow path (828). The flow restricting section (804) including a plurality of flow restricting devices (838, 844, 850) each operable to create a pressure drop. Actuatable devices (830, 832, 834, 836) operably associated with the openings (820, 822, 824, 826) are sequentially actuatable to allow fluid flow through the associated openings (820, 822, 824, 826), thereby sequentially reducing the pressure drop experienced by fluids flowing from the fluid source to the interior flow path (828).

Apparatus for adjustably controlling the inflow of production fluids from a subterranean well

This paper presents the design analysis fabrication and testing of a high-bandwidth piezo-driven parallel kinematic nanopositioning XY stage. The monolithic stage design has two axes and each axis is composed of a doubly clamped beam and a parallelogram hybrid flexure with compliant beams and circular flexure hinges. The doubly clamped beam that is actuated by a piezoelectric actuator acts as a linear prismatic axis. The parallelogram hybrid flexures are used to decouple the actuation effect from the other axis. The mechanism design decouples the motion in the X- and Y-directions and restricts parasitic rotations in the XY plane while allowing for an increased bandwidth with linear kinematics in the operating region. Kinematic and dynamic analysis shows that the mechanical structure of the stage has decoupled motion in XY-direction while achieving high bandwidth and good linearity. The stage is actuated by piezoelectric stack actuators, and two capacitive gauges were added to the system to build a closed-loop positioning system. The results from frequency tests show that the resonant frequencies of the two vibrational modes are over 8 kHz. The stage is capable of about 15 μm of motion along each axis with a resolution of about 1 nm. Due to parallel kinematic mechanism design, a uniform performance is achieved across the workspace. A PI controller is implemented for the stage and a closed-loop bandwidth of 2 kHz is obtained.

Development of a High-Bandwidth XY Nanopositioning Stage for High-Rate Micro-/Nanomanufacturing

Design and dynamics of a 3-DOF flexure-based parallel mechanism for micro/nano manipulation

This paper reports the design and development processes of a totally decoupled flexure-based XYZ parallel-kinematics micropositioning stage with piezoelectric actuation. The uniqueness of the proposed XYZ stage lies in that it possesses both input and output decoupling properties with integrated displacement amplifiers. The input decoupling is realized by actuation isolation using double compound parallelogram flexures with large transverse stiffness, and the output decoupling is implemented by employing two-dimensional (2-D) compound parallelogram flexures. By simplifying each flexure hinge as a two-degree-of-freedom (2-DOF) compliant joint, analytical models of kinematics, statics, and dynamics of the XYZ stage are established and then validated with finite-element analysis (FEA). The derived models are further adopted for optimal design of the stage through particle swarm optimization (PSO), and a prototype of XYZ stage is fabricated for performance tests. The nonsymmetric hysteresis behavior of the piezo-stage is identified with the modified Prandtl-Ishlinskii (MPI) model, and a control scheme combining the inverse model-based feedforward with feedback control is constructed to compensate the plant nonlinearity and uncertainty. Experimental results reveal that a submicron accuracy 1-D and 3-D positioning can be achieved by the system, which confirms the effectiveness of the proposed mechanism and controller design as well.

A Totally Decoupled Piezo-Driven XYZ Flexure Parallel Micropositioning Stage for Micro/Nanomanipulation

This paper reports on a novel piezo-driven, parallel-kinematic, micropositioning XY stage. This monolithic design is comprised of parallelogram four-bar linkages, flexure hinges, and piezoelectric actuators. Kinematic and dynamic analysis shows that the mechanical structure of the stage has a large work space, high bandwidth and good linearity. The stage system was run in open-loop mode to measure the step response and frequency response. The results show that the resonation frequencies of the two vibration modes are 563 and 536 Hz and the damping ratios are 0.049 and 0.0228. Two fiber optic sensors were added to the system to build a closed-loop positioning system. Linear and circular contouring performance in closed-loop mode suggests high scanning performance for such parallel-kinematic stages. The positioning resolution of the stage, limited only by the feedback sensors used, is about 20 nm.

Design analysis, fabrication and testing of a parallel-kinematic micropositioning XY stage

Multi-axis micro and nanopositioning systems are increasingly used in much of the metrology and process equipment related to the field of nanotechnology. This, the first of a two-part series of papers on a novel piezo-driven, parallel-kinematics XYZ nanopositioning (PKXYZNP) stage, concentrates on the development of a viable scheme to achieve pure spatial translation. First, the mechanism is shown to admit closed-form solutions to both; the forward and reverse kinematic problems. The Jacobian and the dynamics of the system indicate that the mechanical structure produces a relatively large work volume, and is capable of high bandwidth and uniform performance across it. The fabrication of the system is described along with some basic testing of its Jacobian and its modal frequencies. Using capacitive gages, the stage is capable of about 85 μm of motion along each axis with a resolution of about 2–4 nm. The controls, testing and performance are discussed in detail in the companion paper [Dong J, Yao Q, Ferreira PM. A novel parallel-kinematics mechanism for integrated, multi-axis nanopositioning. Part 2. Dynamics, control and performance analysis. Precis Eng].

A novel parallel-kinematics mechanisms for integrated, multi-axis nanopositioning: Part 1. Kinematics and design for fabrication

Generally, an apparatus for use in a wellbore includes a flow conduit and a structure defining a tortuous fluid path proximate the flow conduit, where the tortuous fluid path receives a flow of fluid. The tortuous fluid path is defined by at least first and second members of the structure, and the first and second members are movable with respect to each other to adjust a cross-sectional flow area of the tortuous fluid path.

Flow control using a tortuous path

A system for use in a well includes plural flow control devices to control fluid flow in respective zones of the well, where each of at least some of the flow control devices includes a membrane having a permeable material to provide a flow restriction. The membranes of the at least some flow control devices have different permeabilities to provide corresponding different flow restrictions.

Flow control device with a permeable membrane

An inflow control device is disclosed for use in controlling the flow of fluid into a production tubing in a subterranean wellbore. The device is especially adapted for use with sand screen apparatus, but is modular in that it is manufactured separately from the sand screen apparatus. An inflow control device according to the present invention contains an orifice having an opening which is adjustable in size and which is disposed in the device to permit communication of fluid from one end of the body to the other. An inflow control device according to the present invention may be utilized with multiple sand screen assemblies.

Qing Yao

Papers

Design analysis, fabrication and testing of a parallel-kinematic micropositioning XY stage

A novel parallel-kinematics mechanisms for integrated, multi-axis nanopositioning: Part 1. Kinematics and design for fabrication

Flow control using a tortuous path

Flow control device with a permeable membrane

Inflow control device