The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform

H X Zhou - One of the best experts on this subject based on the ideXlab platform.

  • micro positioning of linear Piezoelectric Motors based on a learning nonlinear pid controller
    IEEE-ASME Transactions on Mechatronics, 2001
    Co-Authors: H X Zhou
    Abstract:

    In this paper, a learning nonlinear proportional integral derivative (PID) controller is developed for vaguely modeled nonlinear systems under the influence of significant disturbance and noise. The control scheme is generic in nature, but it is applied specifically to the micropositioning of linear-Piezoelectric Motors in this paper. The design of the control scheme does not require a full mathematical model of the nonlinear system. Simulation and experimental results are provided to highlight the good motion control performance achieved from the control scheme.

Zhihua Feng - One of the best experts on this subject based on the ideXlab platform.

  • high speed low friction Piezoelectric Motors based on centrifugal force
    IEEE Transactions on Industrial Electronics, 2017
    Co-Authors: Fangsheng Huang, Liang Guo He, Jian Chen, Wei Li, Zhihua Feng
    Abstract:

    To develop a new type of Piezoelectric motor with high speed, high power, and high efficiency output, this study proposed a novel low-friction type Piezoelectric rotary motor based on centrifugal force. The construction, working principle, and torque generation mechanism of the motor were described. The motor is started up to a special speed by an external torque, and can be operated in a certain frequency range. The revolution speed of the rotor was designed to be strictly equal to the exciting frequency of Piezoelectric transducers, thus this speed is considerably high. The prototype produced power of up to 8.45 W at 9120 r/min with an average efficiency of 25.3%. The feasibility of the proposed motor was verified, the power consumption was analyzed, and the possibility of realizing a larger efficiency was explained. Finally, the potential applications of this new type of Piezoelectric motor were discussed.

  • Piezoelectric motor based on synchronized switching control
    Sensors and Actuators A-physical, 2013
    Co-Authors: Liang Guo He, Qi Zhang, Bin Ju, Zhihua Feng
    Abstract:

    Abstract A novel working principle for Piezoelectric Motors aimed at high force, speed, and efficiency, as well as long service life is proposed in this paper. The principle is based on the synchronized switching control of harmonic vibration, which is derived from a classical electronic device called silicon controlled rectifier. Unlike the sliding friction coupling mechanism of ultrasonic Motors and the quasi-static operation strategies of inchworm and impact Motors, the new motor overcomes certain critical disadvantages of traditional Piezoelectric Motors. A linear Piezoelectric motor was designed, fabricated and tested. The prototype reached a maximum speed of 8.2 mm/s with a load of 0.5 N, and its maximum load capacity reached up to 5 N. The motor achieved a net efficiency of 18.5% with a load of 2 N.

  • Two-Phase Piezoelectric Motor Using a Multiple-Tube Structure Actuator
    Japanese Journal of Applied Physics, 2009
    Co-Authors: Yuting Ma, Qi Zhang, Fanrang Kong, Zhihua Feng
    Abstract:

    The construction of Piezoelectric Motors using multiple Piezoelectric tubes is proposed in this paper. The static and dynamic characteristics of an eight-tube actuator are studied. The formulas of the bending deflection, moment, and resonant frequency are given. A prototype twophase traveling wave Piezoelectric motor using such a structure is studied. The stator that is composed of eight Piezoelectric tubes produces a wobbling motion when excited in a certain pattern. Both the static and dynamic characteristics of the stator were measured. The rotor’s angular speed possesses a good linearity with the driving voltage amplitude. With a driving voltage of 200 Vp{p at 5.0 kHz, the motor can rotate at the highest angular speed of 319 rpm and produce a maximum stall torque of 1.6 mNm. With an applied voltage of 160 Vp{p and a preload of 0.3 N, the motor’s working efficiency reached about 12%. # 2009 The Japan Society of Applied Physics

Emilio Carlos Nelli Silva - One of the best experts on this subject based on the ideXlab platform.

  • topology optimization applied to the design of linear Piezoelectric Motors
    Journal of Intelligent Material Systems and Structures, 2003
    Co-Authors: Emilio Carlos Nelli Silva
    Abstract:

    Topology optimization is a general computer design method applied to design optimal topology of structures that maximizes (or minimizes) a specified objective function (stiffness, for example) according to some constraints (such as volume). In this work, topology optimization is applied to design linear Piezoelectric Motors. These Motors consist essentially of a flexible structure actuated by two or more piezoceramics excited with different phases. The actuated piezoceramics deform the flexible structure which moves due to friction over a fixed structure, called stator. The flexible structure acts as a mechanical transform by amplifying and changing the direction of the output displacement generated by piezoceramics. The objective is to develop a method which allows us to design systematically a flexible structure for a linear Piezoelectric motor taking into account its performance for a given configuration of piezoceramics. This performance is related to the displacement generated in the motor moving direction and clamping force between the flexible structure and stator. Both quantities depend on the distribution of flexibility and stiffness in the flexible structure domain, which is related to its topology. By designing other types of flexible structures connected to the piezoceramics, novel types of linear Piezoelectric Motors can be obtained. Only quasi-static applications of Motors are considered. The design of an inchworm-type Piezoelectric motor is presented to illustrate the implementation of the method.

  • Design of Piezoelectric Motors using topology optimization
    Smart Structures and Materials 2001: Modeling Signal Processing and Control in Smart Structures, 2001
    Co-Authors: Emilio Carlos Nelli Silva
    Abstract:

    Piezoelectric Motors consist essentially of a coupling structure actuated by two or more piezoceramics excited with different phases. The actuated piezoceramics deform the coupling structure which moves due to friction over a fixed structure, called stator. The motor performance is related to the displacement generated by the motor in the moving direction and clamping force between the coupling structure and stator. Both quantities depend on the distribution of flexibility and stiffness in the coupling structure domain, which is related to coupling structure topology. By designing other types of coupling structures connected to the piezoceramics, novel types of Piezoelectric Motors with enhanced performance can be obtained. In this work, topology optimization is applied to design Piezoelectric Motors. Topology optimization is a general computer design method applied to design optimal structural topology that improves a specified objective function in according to some constraints. The optimization problem is posed as the design of a flexible structure coupled to the piezoceramics that maximizes the output displacement and clamping force in a specified point of the domain and direction. The design of a quasi-static inchworm-type Piezoelectric motor is presented to illustrate the implementation of the method.

Gregory S. Fischer - One of the best experts on this subject based on the ideXlab platform.

  • study of mri compatible Piezoelectric Motors by finite element modeling and high speed digital holography
    2020
    Co-Authors: Paulo Carvalho, Haimi Tang, Payam Razavi, Koohyar Pooladvand, Westly C Castro, Katie Y Gandomi, Zhanyue Zhao, Christopher J Nycz, Cosme Furlong, Gregory S. Fischer
    Abstract:

    The use of intra-operative images with a magnetic resonance imager (MRI) can enable more precise surgical procedures when treating deep brain tumors. The constrained space inside the imager creates the need for robotic assistive devices. However, the strong static magnetic fields, fast changing magnetic gradients and sensitivity to electrical noise create challenges that can be partly addressed by a novel class of MRI compatible resonant Piezoelectric Motors to actuate the robots. These Motors consist of a stator that is mechanically excited by a bonded Piezoelectric ring and a frictionally coupled rotor. Steady-state excitation at certain frequencies leads to specific mode shapes with surface waves having both in- and out-of-plane displacement components. The interaction between the surface waves of the stator with the rotor results in the rotor spinning. Optimal operation of these Motors depends on the stator’s mode shapes generating waves that result in maximizing torquing of the rotor while reducing tangential force components. We present a finite element multi-physics model of the stator using COMSOL in frequency and time-domain. We combine the FEM with stroboscopic and time averaged, high-speed digital holography to create a validated model useful for optimizing motor design and performance. The methodology is used in the study of 30 mm diameter 40–60 kHz driven motor that have been demonstrated in an in-bore MRI compatible surgical robot.

  • Piezoelectrically actuated robotic system for mri guided prostate percutaneous therapy
    IEEE-ASME Transactions on Mechatronics, 2015
    Co-Authors: Hao Su, Kevin Harrington, Weijian Shang, Gang Li, Gregory Cole, Alexander Camilo, Junichi Tokuda, Clare M Tempany, Nobuhiko Hata, Gregory S. Fischer
    Abstract:

    This paper presents a fully actuated robotic system for percutaneous prostate therapy under continuously acquired live magnetic resonance imaging (MRI) guidance. The system is composed of modular hardware and software to support the surgical workflow of intraoperative MRI-guided surgical procedures. We present the development of a 6-degree-of-freedom (DOF) needle placement robot for transperineal prostate interventions. The robot consists of a 3-DOF needle driver module and a 3-DOF Cartesian motion module. The needle driver provides needle cannula translation and rotation (2-DOF) and stylet translation (1-DOF). A custom robot controller consisting of multiple Piezoelectric motor drivers provides precision closed-loop control of Piezoelectric Motors and enables simultaneous robot motion and MR imaging. The developed modular robot control interface software performs image-based registration, kinematics calculation, and exchanges robot commands and coordinates between the navigation software and the robot controller with a new implementation of the open network communication protocol OpenIGTLink. Comprehensive compatibility of the robot is evaluated inside a $3$ -T MRI scanner using standard imaging sequences and the signal-to-noise ratio loss is limited to $15\%$ . The image deterioration due to the present and motion of robot demonstrates unobservable image interference. Twenty-five targeted needle placements inside gelatin phantoms utilizing an 18-gauge ceramic needle demonstrated $0.87$ -mm root-mean-square (RMS) error in 3-D Euclidean distance based on MRI volume segmentation of the image-guided robotic needle placement procedure.

  • Haptic system design for MRI-guided needle based prostate brachytherapy
    2010 IEEE Haptics Symposium HAPTICS 2010, 2010
    Co-Authors: Hao Su, Kevin Harrington, Weijian Shang, Gregory A. Cole, Gregory S. Fischer
    Abstract:

    This paper presents the design of a haptic system for prostate needle brachytherapy under magnetic resonance imaging (MRI) guidance. This haptic system consists of some recently developed MRI-compatible mechatronic devices, including a fiber optic force sensor and a Piezoelectric motor actuated needle driver mounted on a specifically designed 3-axis linear stage. We first propose the teleoperation framework with system architecture, infrastructure and control algorithm for the master-slave haptic interface. Then we introduce some novel sensors and actuators for MRI-compatible mechatronic devices of this haptic system. We developed the force sensor which provides in-vivo measurement of needle insertion forces to render proprioception associated with the brachytherapy procedure. We discuss the sensing principle of the optical sensor which enables two degrees-of-freedom (DOF) torque measurement and one DOF force measurement. The second apparatus of this system is a high precision 3-axis linear stage actuated by Piezoelectric Motors and position sensed by optical linear and rotary encoders and all of them have proved good magnetic compatibility. The needle driver can simultaneously provide needle cannula rotation and stylet translation motion while the cannula translation is engendered by the stage. The independent rotation and translation motion of the cannula and stylet can increase the targeting accuracy while minimize the tissue deformation and damage. The master-slave haptic system is capable of positioning needle and sensing insertion forces thus increasing the operation autonomy, accuracy and reducing the operation time.

  • optimization of Piezoelectric Motors to enhance mr compatiblity for interventional devices
    2009
    Co-Authors: Y Y Wang, C H Sotak, Gregory S. Fischer
    Abstract:

    Y. Y. Wang, M. S. Shazeeb, C. H. Sotak, and G. S. Fischer Mechanical Engineering, Worcester Polytechnic Institute, Worcester, MA, United States, Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, United States, Medical Physics, University of Massachusetts Medical School, Worcester, MA, United States, Radiology, University of Massachusetts Medical School, Worcester, MA, United States

Chunsheng Zhao - One of the best experts on this subject based on the ideXlab platform.

  • finite element method analyses of ambient temperature effects on characteristics of Piezoelectric Motors
    Journal of Intelligent Material Systems and Structures, 2014
    Co-Authors: Xiaolong Lu, Shengqiang Zhou, Chunsheng Zhao
    Abstract:

    There have been numerous experimental reports about the environmental effects on characteristics of intelligent actuators, such as the Piezoelectric Motors. However, the influences of temperature coefficients of material properties, which are the fundamental reasons for the changes of Motors’ output characteristics in different ambient temperature condition, are specially difficult to be acquired through experiments. Thus, the optimization for Piezoelectric Motors driven in extreme environments is scarce till now. This article is aimed to establish one calculating method to solve this problem. First, a theoretical model is developed for investigating the effects of ambient temperature on characteristics of Piezoelectric Motors by the finite element method. And then, the mechanical and electrical characteristics of a Piezoelectric motor are measured to demonstrate the theoretical model. After that, the changes of critical parameters caused by the ambient temperature are discussed. Based on this, the final ...