Linear Stepper Motor Research Articles

多指機能を有する装飾性に優れた量産型電動義手の開発

This paper is described about the design and operation evaluation of the skeleton type electric prosthetic hand for mass production purpose. Through changing an electric motor unit from a servomotor to a linear step motor in order to reduce power consumption against the previous prosthetic hand [4] [5] and through changing the initial shape of the glove were achieved. Then a user-evaluation was performed in order to check grip shape against various forms of objects. It was confirmed that the new prosthetic hand can realize various grips according to objects with various shaped as like as previous skeleton type prosthetic hand.

Open Modular Hardware and Software Kit for Creations of Remote Experiments Accessible from PC and Mobile Devices

The goal of this paper is to introduce open modular hardware and software system “iSES Remote Lab SDK” (iSES – internet School Experimental Studio) designed for easy creation of real remotely controlled laboratories (RCL) that are accessible from PC, tablets and mobile phones. Open modular system “iSES Remote Lab SDK” consists of approx. 20 freely distributable JavaScript objects in a commented source code. Widgets are highly configurable and provide many well documented options and allow to build a complex measurement and control interface with data and video transfer. Open modular system “iSES Remote Lab SDK” can communicate with different measurement platforms (ISES, Arduino are ready; CMA CoachLab, Vernier etc. are tested), and also common universal measurement devices with a COM or USB port, further universal rotation and linear motion stepper motors, etc.). We will introdukce our 18 online advanced remote labs. Any user may have an access to the RCL on PC and mobile devices (iPad, smart phone, etc.) as well. Even non-programmers can build up a simple RCL and publish it in 15 minutes on the Internet! System “iSES Remote Lab SDK“ has obtained the GOLC Online Laboratory Award 2016 in the category Remote Controlled Lab [1].

Highprecision auto-balance of the time-domain pulsed homodyne detector

Quantum key distributions, which could make legitimate communication parties Alice and Bob achieve the same random key with unconditional security, will have broad applications in defense, commerce, and communication. The protocol of the continuous variable quantum key distribution (CVQKD) has many advantages, such as easy preparation of the light source, high detector efficiency, and good compatibility with the classic fiber-optic communication systems. In recent years, great progress in the research of CVQKD has been made both theoretically and experimentally. In the protocol, the quadratures of the optical field with Gaussian or Non-Gaussian modulation are employed as the carriers of the key.The quadratures of the pulsed optical quantum states in CVQKD can be detected with a time-domain pulsed homodyne detector. The performance of the detector has great influences on the excess noises and the safe key rate of the quantum communication system. The measurement accuracy, which depends crucially on the common mode rejection ratio and the long-term stability, is the key performance of the detector. In order to improve the accuracy of measurement and avoid saturating the detector, we propose and demonstrate a technique to balance the two output beams of a 50/50 fiber coupler of the homodyne detector automatically. The auto-balance technique, which improves the long-term stability and high common mode rejection ratio, is described in the following.Firstly, the relation between the balance degree and the measurement accuracy is theoretically analyzed in detail. The result shows that a balance degree larger than 10-4 should be reached to ensure a high precision measurement when the intensity of the local oscillator pulse is 108 photons per pulse. Secondly, a fiber-based variable attenuator based on computer-controlled linear stepper motor is designed. The linear stepper motor that is used to drive the fiber coils has a small dimension of 20 cm20 cm28 cm and a minimum step size of 78 nm, and is controlled through the I/O port of a multifunction data acquisition card connected to a computer. The attenuations of the fiber coils of different radii are detected. The precision of attenuation is estimated to be on the order of 10-6 per 100 nm.The principle of the feedback control is described. A method of changing step-size which depends on the balance degree is proposed to fulfill a fast auto-balance process. Using the auto-feedback-control system, a balance degree of about 1.5610-6 can be achieved. The procedure of auto-balance takes about 1 s, and the evolution curves that represent the transformation process from various unbalanced states to the balanced state are presented.The auto-balance apparatus can ensure that the time-domain pulsed homodyne detector run stably in a longterm with a high common mode rejection ratio. The nonlinear and saturation effects due to the drift of the balance point are eliminated. The presented auto-balance time-domain pulsed homodyne detector can be well integrated into the continuous variable quantum key distribution system, and is expected to play an important role in improving the measurement accuracy and reducing the excess noises of the system. We believe that it could also be found to have potential applications in other areas.

Analytical and experimental approach of the high density transverse flux linear stepper motor

Detailed analytical and experimental approaches were performed to calculating the ratio of the pull-in thrust to the input power of High Density Transverse Flux linear Stepper Motor (HDTFLSM) with considerations of the electrical time constant, the mechanical time constant and the friction. The analytical approach involves the use of Fourier series analysis to derive the equation for the pull-in thrust to input power ratio. The experimentation was performed under different load conditions until the motor come to the standstill value. A chopped voltage was applied to motor at different speeds and the obtained results were compared with those for normal voltage. Comparison between analytical and experimental results shows good agreement, for instance at 0.22 m/s the difference percentage on normal voltage and chopped voltage are 6.1% and 6.7%, respectively. The chopped voltage has higher ratio of the pull-in thrust to the input power compare to normal voltage so that the machine performance can be improvised to a greater extent. The maximum improvement percentage of 18.8% on pull-in thrust to input power ratio for motor with chopped voltage was obtained at 0.22 m/s.

A Robot for Capillary Massage of the Surface of the Head

A robot for capillary massage of the head surface based on the Murashka octopus massager is described. Advantages of the robot with linear stepper motor are discussed. The robotic massager suggested in this work may prove effective in recovery medicine.

Abstract 3920: In vivo tyrosinase reporter gene imaging with multispectral photoacoustic technology.

Abstract Photoacoustic imaging is a powerful tool for assessing tumor vasculature and oxygen saturation as well as detecting contrast agents for molecular imaging. Another exciting possibility is to visualize gene expression by using a reporter which produces a photoacoustic contrast agent. Tyrosinase is such a reporter in that its expression results in the production of melanin, which gives a strong photoacoustic signal. Here we describe the use of a commercially available photoacoustic (PA) imaging system (Vevo LAZR, VisualSonics, Toronto) to image inducible gene expression in subcutaneous xenograft tumors using tyrosinase as a reporter gene. The photoacoustic imaging system generated light from a tunable laser (680 - 970 nm) which was delivered through fiber optic bundles integrated into a linear array transducer (LZ-250, fc = 21 MHz), mounted to a linear stepper motor for 3D imaging. Animals (n=3) having MCF-7 xenograft tumors on either flank transfected with (+TYR) or without (-TYR) doxycycline-regulated tyrosinase were imaged before and one week after the induction of tyrosinase expression. 3D images of the tumors were acquired using multiple wavelengths (680, 750, 800, 850, 900 and 950nm) and 2D images were acquired across the entire wavelength range of the laser to generate absorption curves for blood and melanin. To confirm the presence of melanin and distinguish it from the endogenous blood signal, one animal was exsanguinated and the tumor was imaged again. Approximately 1mm-thick slices of the tumors were taken and photographed for visual confirmation of the presence of melanin. Comparison of pre- and post-doxycycline images of +TYR tumors clearly showed enhanced contrast in the tumor which closely matched the absorption spectrum of melanin. This signal persisted upon exsanguination. -TYR tumors showed signal which corresponded with the spectra of oxy and deoxy hemoglobin and changed little over the course of the experiment. Visual inspection of the excised sliced tumors revealed pigmentation in the +TYR tumors which was absent in the -TYR tumors. Here we have shown the ability of the Vevo LAZR photoacoustic imaging system to visualize inducible reporter gene expression in vivo. This has implications for assessing genetically controlled cellular processes and their response to anti-cancer drugs but also for monitoring gene therapy for cancer treatment non-invasively. Citation Format: Andrew Heinmiller, Minalini Lakshman, Dave Bates, Andrew Needles, Catherine Theodoropoulos, Robert J. Paproski, Roger J. Zemp. In vivo tyrosinase reporter gene imaging with multispectral photoacoustic technology. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3920. doi:10.1158/1538-7445.AM2013-3920

Automated multichannel broadband spectrum analysis of fibre-optic grating sensors

In this paper, we report methods for spectrum analysis and data processing algorithms. An automated multi–channel spectrum measurement system is introduced with controlled fibre–optic signal switching and spectrum analysis with linear CCD photodiode array, diffraction grating and precise stepper motor. The designed system demands advanced measurement and data processing techniques. This paper reports the implemented methods for automated multi–channel measurements, accuracy improvement, noise cancellation techniques and fibre–optic grating sensor measurements.

Finite Element Methods Applied to the Tubular Linear Stepping Motor

In this paper proposes a Finite Element Methods analyzing applied to the linear tubular stepping actuator. The linear displacement is modeled by means of a layer of finite elements placed in the air gap. The design of the linear stepper motor for achieving a specific performance requires the choice of appropriate tooth geometry. The magnetic field of the actuator has been analyzed using the finite element method over a current-displacement variation. The magneto static field and electromagnetic force was introduced in order to predict before construction, the inductance values according to the displacement and the currents into the coils. The results were obtained for the magnetic flux density distribution and the electromagnetic force for different positions and current.

Recession in a linear stepper motor based on piezoelectric actuator and electrorheological clampers

A linear inchworm-type stepper motor based on piezoelectric actuator and comb shape electrorheological (ER) clampers was developed and tested. A recession phenomenon in the movement of the motor was found and was significantly affected by the driving voltage of the piezoelectric actuator and ER fluids. A dynamic model to analyze the mechanism of the recession was established. The force ratio of the viscoelastic clamping force (applied high electric field) to the viscous damping force (zero field) of ER fluids is the critical factor which determines the recession. The ratio is also affected by the extension or contraction rate of the actuator during movement, which is affected by the charging and discharging processes. With a relatively large distance between the clamper electrodes and a small displacement activated by the extension of the piezoelectric actuator, the instantaneous shear rate might not be sufficiently high, preventing ER fluids from attaining a shear-thickened and high-strength state. The ratio of yield strength to the viscous strength of ER fluids during movement should be as large as possible to reduce the recession displacement.

High Speed Propulsion System for UAQ4 Magnetic Levitating Train

This paper presents the design of a novel high speed propulsion system for UAQ4 magnetic levitating train, the feasibility of which has been successfully tested and confirmed in laboratory. A direct-current linear stepper motor that uses permanent magnets distributed on the central beam of track as the stator and the direct current power supplied coils on-board the vehicle as the rotor is proposed and analyzed. The motor performances are evaluated by varying the system parameters by carrying out a finite element numerical model refined with experimental data. The main components of a real scale motor with speed up to 580 km/h for the UAQ4 train application is measured and discussed.

Control Design and Implementation for Sawyer Motors Used in Manufacturing Systems

In this paper, hardware integration and control design for a dual-axis linear stepper (Sawyer) motor are addressed. In particular, the Sawyer motor used in the Yaskawa/MotoMan manufacturing system, which is utilized in various applications such as assembly, packaging, sorting, and probing, is considered. These motors are equipped with four optical sensors with a position resolution of 0.25 μm. A detailed mathematical model of the motor is developed, and two control designs for position tracking, namely, a PD (or PID) controller and a robust adaptive nonlinear controller, are described along with experimental results. A number of practical issues (such as delay/latency, finite sampling time, sensor noise, commutation rate, and motor rotation) that must be addressed to achieve high performance are outlined and experimentally demonstrated. Both of the considered controllers utilize knowledge of motor position and velocity in all axes. Current measurements are not required. Either numerical differentiation or a dynamic observer can be used to construct the velocity signals from the measured position data. The designed robust adaptive nonlinear controller provides practical stabilization of position tracking errors and utilizes adaptations so that no knowledge of the electromechanical system parameters is required. The controller is robust to load forces and load torque (i.e., disturbance torque in yaw axis), friction, and cogging forces. Furthermore, the controller corrects for the unintended yaw and achieves synchrony of the motor and rotor teeth.

Design and modelling of a linear switched reluctance actuator for biomedical applications

This paper deals with a design of linear stepper motor for biomedical applications. The involved biomedical system is a syringe pump generally used for continuous drug infusion. The syringe pump consists of a linear switched reluctance motor (LSRM) coupled to a syringe plunger. In order to determine the axial force to control the syringe plunger, it was necessary to begin by evaluating the thrust force. The latter constituted the key element for designing the motor. Based on the concept of energy balance, a simplified analytical model was developed to predict the electromagnetic characteristics of the linear switched reluctance motor. The validity of results was ensured by direct comparison with the finite element method (FEM). Key words: Linear switched reluctance motor, syringe pump, modelling, finite-element.

Design of a Fluorescence-Based System for Measurement of Transmembrane Potential Variations of Electrically and Mechanically Stimulated Cardiomyocytes

Cardiomyocytes are electrically-active heart cells whose electrical properties vary with the local electrical and mechanical environment. Variations in myocytes electrical properties are known to play a role on abnormal rhythms.The purpose of the project is to design a fluorescence-based photodetection system for measurement of transmembrane potential variations by combined electrical and mechanical stimulations in post-culture cardiomyocytes.The isolated cardiomyocytes are seeded on a 10mm x 10mm x 0.127mm silicon sheet held by a pair of pliers, coupled to a stretcher apparatus made of two linear guide systems and two computer controlled linear stepper motors. The cells are kept in bubbled Tyrode solution and are electrically stimulated during the 10 minutes staining by the voltage-sensitive dye di-8-Anepps (Invitrogen) at 5 μmol/L concentration. Field electrical stimulation is done by a pair of parallel carbon electrodes with grounded anode. The cathode voltage is supplied by a bipolar isolation amplifier circuit whose input is a set of pulses from the digital-to-analog converter of a National Instruments card (NI USB-6221). The light source is a green LED array (wavelength = 523nm, NTE Electronics Inc.), with intensity controlled by a Darlington array receiving TTL signals. The emitted fluorescence is filtered (λ > 610nm), converted to voltage with a fast photodiode (S1226-5BK, Hamamatsu), and amplified by an instrumentation amplifier (AD524ADZ, Analog Digital Inc). The voltage is then digitized with a National Instruments card, filtered and saved for post-experiment analysis.Each sub-system has been successfully validated. Testing the whole system with cardiac-derived HL1 cells allowed final improvement on the signal-to-noise ratio and optimization of excitation intensity. This ready to use bioinstrument will play a key role in further studies on cultured cardiomyocytes.

An electrostatic 3-phase linear stepper motor fabricated by vertical trench isolation technology**This work was presented in part at the 19th MicroMechanics Europe Workshop (MME), 28–30 September 2008, Aachen, Germany.

We present the design, microfabrication and characterization of an electrostatic 3-phase linear stepper micromotor constructed with vertical trench isolation technology. This suitable technology was used to create a monolithic stepper motor with high-aspect-ratio poles and an integrated 3-phase electrical network in the bulk of a standard single-crystal silicon wafer. The shuttle of the stepper motor is suspended by a flexure to avoid any mechanical contact during operation, enhancing the precision, repeatability and reliability of the stepping motion. The prototype is capable of a maximum travel of +/−26 µm (52 µm) at an actuation voltage of 30 V and a step size of 1.4 µm during a half-stepping sequence.

Fabrication and test of multilayer microcoils with a high packaging density

In magnetic microactuation, the energy converted by a magnetic microactuator is proportional to its volume (Kohlmeier et al., Microsystem Technol 8(4–5):304–307, 2002a). For that reason, it is desirable not only to choose an actuator’s active part with a sufficient footprint size, but also with a substantial building height. By applying UV depth lithography, such a requirement may be fulfilled. This paper investigates the application of high aspect ratio systems technology to fabricating a compact microcoil as field generating element. The coil has four layers. To take optimal advantage of the building height, the insulation film between the coil layers was kept small by applying a thin Si3N4 layer. The coils are intended for the integration in a magnetic microlevitation system serving as an electromagnetic guide for a linear microhybrid step motor (Budde et al., In: Proceedings of the 9th int. conf. on new actuators, pp 665–668, 2004).

TriM: An Ultra-Accurate High-Speed Six Degree-of-Freedom Manipulator Using Planar Stepper Motors

In this paper, we propose a novel six degree-of-freedom positioning system. This mechanism is a tripod structure with inextensible limbs actuated at the base by two-dimensional linear stepper motors (other types of actuators may also be utilized). This manipulator has a closed-chain kinematic structure. Both the direct and the inverse kinematics of the manipulator are presented in detail. While the inverse kinematics are obtained in closed form, the direct kinematics can not be solved in closed form and an algorithm is provided for numerically computing the direct kinematic solution. A detailed dynamic model of the positioning system is also provided. The dynamics of the actuators (Sawyer motors) are also included in the dynamic modeling. The design of the tripod manipulator (TriM) included a kinematic optimization of the system parameters to maximize the manipulator workspace. The proposed manipulator achieves large range of motion in all the 6 degrees of freedom. Furthermore, high resolution and high speed motion may be achieved in all axes due to the actuators used and the direct-drive nature of the manipulator.

Solar photovoltaic water pumping system using a new linear actuator

In this paper a photovoltaic solar pumping system using a new linear actuator is presented. This linear actuator is a double-sided flat two-phase variable-reluctance linear stepper motor that moves a piston-type water pump with the help of a rope, a pulley and a counterweight. The entire actuator pump ensemble is controlled by a simple electronic unit that manages the electric power generated by a photovoltaic array. The proposed system is suitable for rural communities in developing countries because it is reliable, affordable and easy to maintain.

Linear Step Motor Based on Magnetic Force Control Using Composite of Magnetostrictive and Piezoelectric Materials

We assemble a composite of giant magnetostrictive material (Terfenol-D) and stack piezoelectric transducer (PZT) actuator, and use it in a linear step motor. Control of the magnetic force exploits the inverse magnetostrictive effect of the Terfenol, in which the composite and a magnetic circuit in combination controls the magnetic force on a movable yoke with the voltage of the PZTs via mechanical stress. The unique feature of this arrangement is zero power consumption needed to maintain a constant magnetic force; once the PZTs have been charged, no current flows in static operation due to the capacitive property. A composite having simple configuration, bonding both Terfenol and PZT to iron yokes, is verified to control the magnetic force over wide variations under appropriate prestress conditions. A linear step motor with four composites as a stator also demonstrates variation of the thrust force and the possibility of motion control. Microstep motion of the mover was achieved using sinusoidal voltage, and zero current was observed with stationary voltage. The principle should be advantageous in high-precision positioning

In vivo measurement of translational stiffness of rabbit knees

This paper describes the design, evaluation, and preliminary results of a specialized testing device and surgical protocol to determine translational stiffness of a rabbit knee, replicating the clinical anterior drawer test. Coronal-plane transverse pins are inserted through the rabbit leg, two in the tibia and one in the distal femur, to hold and reproducibly position the leg in the device for tests at multiple time points. A linear stepper motor draws the tibia upward then returns to the home position, and a load cell measures the resisting force; force–displacement knee stiffness is then calculated. Initial evaluation of this testing device determined the effects of preconditioning, intra-operator repeatability, rabbit-to-rabbit variability, knee flexion angle (90° vs. 135°), and anterior cruciate ligament (ACL) sectioning (0%, 25%, 50%, 75%, 100%). Knee stiffness generally decreased as ACL sectioning increased. This testing device and surgical protocol provide an objective and efficient method of determining translational rabbit knee stiffness in vivo, and are being used in an ongoing study to evaluate the effect of knee instability (via partial to complete ACL sectioning) on the development of post-traumatic osteoarthritis.

Simple automatic device for real time sampling of gas production by a reactor

An innovative automatic device, allowing periodically drawing samples of the gases produced by a generic reactor, is presented. The gases evolving during the reaction are collected in a storage manifold, equipped with a variable volume consisting of a stainless steel bellow, whose expansion or contraction is driven by a linear step motor. A capacitive gauge monitors the pressure inside the storage manifold, while a feedback control loop reacts to any pressure change adjusting the variable volume (by means of the step motor) in such a way to keep the pressure at a desired set point P0. As long as the reaction proceeds, the gas production results in a progressive expansion of the variable volume, whose instantaneous value is constantly monitored by means of a slide potentiometer, whose lever is rigidly connected to the bellow’s moving extremity. Once the bellow’s expansion has reached a predetermined volume increment ΔV, which means that an amount of gas P0ΔV has been produced and collected in the storage circuit, a quantity P0VS⩽P0ΔV of gas is released to the analysis system. A set of electropneumatic valves, automatically operated by the control system, allows for gas delivery to the analysis equipment and retrieval of the set point pressure, by compression of the variable volume, with no influence on the reaction. All relevant parameters are monitored and logged on a personal computer. The control and data acquisition software, made out using National Instrument LABVIEW™, also provides control of the analysis equipment. The ability of the proposed setup to not affect the ongoing process allows real time monitoring (by drawing samples at regular time intervals during the reaction) of the gas production. Moreover, since the amount of gas P0VS drawn at each sampling is always the same, it is possible to establish at a glance whether or not there are changes in the concentration of any component, by directly comparing the results of the analysis of successive samples.