Maximum Travel Range Research Articles

A rigid and compact piezoelectric motor with high output efficiency.

We introduce a novel piezoelectric stepper motor featuring high compactness, rigidity, and any direction operability. Here, not only is the structure of high novelty but also the working principle very simple. The piezo stacks unit is sandwiched between two spring finger pieces, with almost equal clamping forces applied between the top of the piezo stacks' unit and the spring finger piece. Applying individual driving signals to each of the five piezo stack pairs, causing deformation one by one in the same direction, followed by simultaneous recovery in the reverse direction, enables movement of the frame part. The optimized clamping force of the piezoelectric stack units and spring fingers ensures maximum output force. The motor's operational capability at low threshold voltages, specifically 8V for downward movement and 10V for upward movement, confirmed its efficacy in both vertical and horizontal directions. The motor's operational capability at a low threshold voltage of 10V confirmed its efficacy in both vertical and horizontal directions. At room temperature, step size ranges from 0.3 to 7.4 µm at 20Hz frequency and varying driving voltage from 10 to 180V. It has a maximum travel range of about 5mm and can lift a maximum load of 220g in an upward direction, so the maximum output force generated by this motor is 2.2 N. The compact and rigid design is capable of building an atomically resolved scanning probe microscope, and its working ability has the potential to use the cleavage of different types of samples in limited space environments, such as the small-bore superconducting magnet and low temperature.

Development of a piezoelectric hybrid-driven nanopositioner using combined leaf-spring-shaped and C-shaped flexure hinge mechanism

This paper presents a novel piezoelectric hybrid-driven nanopositioner using combined leaf-spring-shaped and C-shaped flexure hinge mechanism. The piezoelectric hybrid-driven nanopositioner combines the piezoelectric stick-slip-driven nanopositioner and piezoelectric scanner in a single and compact device. This advance can decrease the size of nanoscratch-AFM hybrid system and make nanoscratch-AFM hybrid system compatible with the limited space of SEM vacuum chamber. A flexure hinge combining leaf-spring-shaped mechanism and C-shaped mechanism is developed to improve the load capability of piezoelectric stick-slip-driven nanopositioner. Unlike existing methods of improving load-capability by decreasing kinetic friction force value, the proposed flexure hinge employs C-shaped structure to decrease the retraction motion time of kinetic friction force, which can achieve high-load and compact structure simultaneously. Finite element analysis is implemented to optimize the thickness of the leaf-spring-shaped mechanism and diameter of the C-shaped mechanism. A prototype is fabricated and its experimental system is established. The mechanical output experiments show that the piezoelectric scanner achieved a maximum travel range of 4.9 μm, and piezoelectric stick-slip-driven nanopositionerm achieves a maximum load of 2 Kg. Experimental results of the nanoscratch-AFM hybrid system inside a standard SEM HITACHI SU5000 demonstrate that the proposed piezoelectric hybrid-driven nanopositioner is capable of nanoscratch positioning.

On‐Chip Electrically Driven Tunable Meta‐Lens for Dynamic Focusing and Beam Steering

AbstractThe on‐chip meta‐lenses consisting of subwavelength slot arrays with lateral gradients have shown great potential for parallel signal processing and optical computing. The dynamic tuning mechanisms which are necessary steps toward exploiting the applications of the on‐chip meta‐system have been rarely mentioned yet. Here, a free‐form functional microheater via topology design is proposed to manipulate the refractive index distribution, allowing for flexible optical wavefront shaping. For a proof‐of‐concept, wide range of dynamic focusing and beam steering are demonstrated via a tunable meta‐lens on silicon photonic platform. The continuous scanning of the focused beam is experimentally achieved with a maximum travel range of 100 µm in the longitudinal direction (≈95 nm mW−1) and 25 µm in the lateral direction (≈20 nm mW−1). The thermal‐optic tuning elements can response the electrical control within ≈41.2 µs. A waveguide array at the focal plane is used to characterize the device. The on‐chip loss of the tunable meta‐lens is measured to be <1 dB including the coupling loss from slab to single‐mode waveguide. The proposed tunable meta‐lenses are fabricated via a standard silicon photonic process and allow for arbitrarily two dimensional (2D) beam steering. It offers great versatility for on‐chip meta‐systems with a wider scope of functionalities and applications.

The first rolling load simulator (ROLLS) for testing bridges in Canada and its application on a full-scale precast box girder

This paper describes the development of a unique rolling load simulator (ROLLS) for testing bridge superstructure with a footprint up to 4 m ×17 m, and its first application to test a full-scale 1220 mm ×900 mm ×16000 mm B900 prestressed concrete box girder. This facility at Queen’s University in Kingston, Ontario, is the first of its kind in Canada. ROLLS can apply cyclic loading in a controlled laboratory environment, under realistic highway scale ‘rolling wheel loads’, in lieu of the conventional ‘pulsating stationary loads’. It has two half-axles of a large tandem, each comprising a dual 1140 mm diameter air-inflated tires spaced at either 1.2 or 2.4 m. Each half-axle can apply up to 125 kN, representing the heaviest half-axle load of the CL-625 design truck of the Canadian Highway Bridge Design Code (CHBDC). The maximum travel range and speed are 14.9 m and 6 m/s, respectively. A case study involving analysis of a bridge with eight adjacent B900 box girders of 27.6 m span was carried out prior to experimentally testing one of the girders using ROLLS. Load distribution analyses were conducted using both (i) a finite element model of the full bridge under various CL-625 truck loading configurations and (ii) the CHBDC load distribution method, and both agreed well. Scaling analysis of the girder load share was then conducted to account for shortening it to 16 m to fit in the laboratory, resulting in two-115 kN ROLLS design loads, 1.2 m apart. Multiple passes were conducted at various loads of 40%–100% of the design load, at speeds of 1–5 m/s to examine the machine and girder behaviours. It was found that the applied load fluctuates by less than 10% of full capacity and a 0.13 s/cycle time lag occurs. The measured girder deflection and elastic strains were 11%–20% lower than predicted theoretically. With the two half-axles assembly spaced at 1.2 m, the apparatus has the ability to complete three million cycles in approximately 4.5 months if ran continuously at 5 m/s.

Two-Phase Lorentz Coils and Linear Halbach Array for Multiaxis Precision-Positioning Stages With Magnetic Levitation

In this paper, a new framework for linear permanent-magnet (PM) machines with applications in precision motion control is proposed and validated. A single forcer generating two independent force components in two perpendicular directions is the fundamental unit of the framework. Each forcer consists of two planar Lorentz coils separated by a 90° or 270° phase difference and parallel to a Halbach magnet array. Many coil pairs can be assembled to the same platen to move over a common magnet matrix, forming a linear or planar PM motor. Advantages of this framework include a linear system model, the capability to magnetically levitate the mover in multiaxis stages, and that to generate long translational motion range. The framework developed herein is validated by a six-degree-of-freedom magnetically levitated (maglev) stage. The dimension of the moving platen's frame is $\text{14.3}{\,\text{cm}}\times \text{14.3}{\,\text{cm}}$ , and its total mass is 0.75 kg. The achieved positioning resolution in translations along $X,Y$ , and $Z$ is 10 nm. The positioning resolution in out-of-plane rotation is $\text{0.1}\,\mu {\text{rad}}$ , which is a record in the literature. The maximum travel range in $XY$ with laser interferometers is ${\text{56}\,\text{mm}}\times \text{35}\,{\text{mm}}$ , limited by the size of the precision mirrors. With the coils’ total mass of only 0.205 kg, the achieved acceleration is 1.2 m/s2. Experimental results exhibit reduced perturbations in other axes of in-plane motions.

Jam-free gear\u2013clutch mechanism for load-sensitive step transmission in robotic joint

This paper introduces a novel gear–clutch mechanism that takes advantage of the difference between the directions in the reaction forces that occur during meshing and jamming to ensure jam-free engagement of the gears. The proposed mechanism is a more compact advancement of the previously developed linear rack-tilting clutch used to provide a step change in the reduction ratio. Mathematical models of the jam-free and stable meshing condition of the proposed mechanism are developed and experimentally verified, along with a discussion and recommendations to be considered as design guidelines. Additionally, a singularly actuated robotic joint prototype is developed to examine the performance of the proposed clutch mechanism. The joint was driven by a small 2-W DC motor. The maximum output torque was 4 Nm with a maximum travel range of over 200^circ during the high-force phase, and the maximum speed was 252^circ/s with an infinite travel range during the high-speed phase. The mechanism exhibits potential for applications that benefit from a step transmission and long force-exerting travel range such as vices, grippers, and industrial punching and shearing machines, as well as robotic arms and power assist exoskeletons.

Numerical investigation into slope-climbing capability of fuel cell hybrid scooter

Fuel cell hybrid scooters provide an adequate performance on horizontal road surfaces, but perform less well when climbing slopes. In the present study, the slope-climbing capability of a fuel cell hybrid scooter is examined in simulations. The simulations focus specifically on the effects of the slope inclination angle, riding speed and rider weight on the power consumption, hydrogen consumption, and maximum travel range of the scooter. The validity of the numerical model is confirmed by comparing the numerical results for the power consumption of the scooter with the experimental and analytical results presented in the literature. The simulation results show that the power consumption and hydrogen consumption increase with an increasing slope inclination angle, riding speed and rider weight. Moreover, it is shown that given an initial hydrogen mass of 90g, a constant riding speed of 40kmh−1, and a rider weight of 60kg, the maximum travel range reduces from 47km to 5km as the slope inclination angle is increased from 0° to 40°. In general, the results presented in this study confirm that the proposed simulation model provides a valid means of characterizing the performance of a fuel cell hybrid scooter under typical urban riding conditions.

CNC Paths Optimization in Laser Texturing of Free Form Surfaces

Laser Texturing and Laser Engraving of free form surfaces are interesting alternative to EDM and micro milling in the fabrication of moulds and dies. The material removal rate of this process is typically very low and the maximum working area is limited by the maximum travel range of the galvanometric scanning head and also by the maximum deflection of the scanner or the surface curvature. As a consequence, in order to manufacture large or free form surfaces, a set of placements of the scanning head respect to the work piece must be calculated and controlled by the CNC.The number of these placements can be quite high due the small amount of material removed in each of them and the non-operative time spent to move the scanning head can be relevant compared to the overall time. In this work a method based on the solution of the Traveling Salesman Problem is proposed with the aim to optimise the number of displacements of the scanning head and generally in order to reduce the number of movement of the numerically controlled axes.The method that takes into account both the architecture and the dynamic characteristics of a 5 axis CNC system was implemented in the CALM (Computer Aided Laser Manufacturing) software used to program the laser path for part texturing and applied in industrial cases.

A decoupled 2-DOF flexure-based micropositioning stage with large travel ranges

SUMMARYIn this paper, a new flexure-based micropositioning stage (FMPS) is proposed to achieve decoupled XY translational motions and large travel ranges. The stage consists of four independent kinematic chains, each comprising two flexure-beam prismatic joints. The mechanism with such a special topological structure enables the motions of the platform strictly along XY axes and minimizes the parasitic rotation in theta axis. The kinematics and dynamics analysis of the mechanism are conducted to evaluate the performance of the mechanism in terms of travel range, parasitic motions, linearity, as well as natural frequency. According to the developed models, a parameter optimization of the mechanism is performed under the condition of the maximum travel range. The finite element simulation is carried out to examine the mechanical performance and the theoretical models. The experimental results show that the proposed FMPS possesses a workspace of 600 × 600 μm2, a relative coupling error of 0.6%, and the natural frequencies of 209.7 Hz and 212.4 Hz for the first two modes.

Primary Frequency Response From Electric Vehicles in the Great Britain Power System

With the increasing use of renewable energy in the Great Britain (GB) power system, the role of electric vehicles (EVs) contributes to primary frequency response was investigated. A tool was developed to estimate the EV charging load based on statistical analysis of EV type, battery capacity, maximum travel range and battery state of charge. A simplified GB power system model was used to investigate the contribution of EVs to primary frequency response. Two control modes were considered: disconnection of charging load (case I) and discharge of stored battery energy (case II). For case II, the characteristic of the EV charger was also considered. A case study shows results for the year 2020. Three EV charging strategies: “dumb” charging, “off-peak” charging, and “smart” charging, were compared. Simulation results show that utilizing EVs to stabilize the grid frequency in the GB system can significantly reduce frequency deviations. However the requirement to schedule frequency response from conventional generators is dynamic throughout the day.

Design of a compact serial-kinematic scanner for high-speed atomic force microscopy: an analytical approach

A systematic procedure for designing a high-speed, compact serial-kinematic XYZ scanner for atomic force microscopy is presented in this Letter. Analytical stiffness calculations are used to estimate the first natural frequency and travel range of the scanner. Design and characterisation of the scanner are presented. Results of finite-element analysis and experimentation on the scanner revealed natural frequencies of 10, 7.5 and 64 kHz for X, Y and Z stages, respectively. Maximum travel range of 8, 6 and 2 µm were measured along x, y and z directions. Performance evaluations were conducted by implementing the scanner in a commercial atomic force microscope. Images of a 6×4.5 µm area of a calibration grating were captured at line rates of 10, 50, 78, 100, 120 and 150 Hz with 256×256 pixel resolution. Limitations in design and suggestions for improvement of the scanner performance are discussed.

High-Performance Shuffle Motor Fabricated by Vertical Trench Isolation Technology

Shuffle motors are electrostatic stepper micromotors that employ a built-in mechanical leverage to produce large output forces as well as high resolution displacements. These motors can generally move only over predefined paths that served as driving electrodes. Here, we present the design, modeling and experimental characterization of a novel shuffle motor that moves over an unpatterned, electrically grounded surface. By combining the novel design with an innovative micromachining method based on vertical trench isolation, we have greatly simplified the fabrication of the shuffle motors and significantly improved their overall performance characteristics and reliability. Depending on the propulsion voltage, our motor with external dimensions of 290 μm × 410 mm displays two distinct operational modes with adjustable step sizes varying respectively from 0.6 to 7 nm and from 49 to 62 nm. The prototype was driven up to a cycling frequency of 80 kHz, showing nearly linear dependence of its velocity with frequency and a maximum velocity of 3.6 mm/s. For driving voltages of 55 V, the device had a maximum travel range of ±70 μm and exhibited an output force of 1.7 mN, resulting in the highest force and power densities reported so far for an electrostatic micromotor. After five days of operation, it had traveled a cumulative distance of more than 1.5 km in 34 billion steps without noticeable deterioration in performance.

Method for gauge block measurement with the heterodyne central fringe identification technique

In a modified Michelson interferometer, the top face of the wringing platen is first identified using the heterodyne central fringe identification technique. Then the reference mirror located in the other arm is moved by a precision translation stage until the top face of the tested gauge block is also identified with the same technique. The displacement of the mirror is exactly equivalent to the length of the tested gauge block. The measurable range of the interferometer relates to the maximum travel range of the translation stage and its uncertainty depends on the uncertainty of the heterodyne central fringe identification method and the resolution of the translation stage.

An in situ tensile tester for studying electrochemical repassivation behavior: Fabrication and challenges

An in situ tensile rig is proposed, which allows performing electrochemical (repassivation) experiments during dynamic mechanical testing of wires. Utilizing the basic components of a conventional tensile tester, a custom-made minitensile rig was designed and fabricated. The maximal force that can be measured by the force sensor is 80 N, with a sensitivity of 0.5 mV/V. The maximum travel range of the crosshead induced by the motor is 10 mm with a minimum step size of 0.5 nm. The functionality of the tensile test rig was validated by investigating Cu and shape memory NiTi wires. Wires of lengths between 40 and 50 mm with varying gauge lengths can be tested. An interface between wire and electrochemical setup (noncontact) with a smart arrangement of electrodes facilitated the electrochemical measurements during tensile loading. Preliminary results on the repassivation behavior of Al wire are reported.

Controller design and implementation of six-degree-of-freedom magnetically levitated positioning system with high precision

This paper presents the controller design and implementation of a high-precision six-degree-of-freedom (6-DOF) magnetically levitated (maglev) positioner. This high-precision positioning system consists of a novel concentrated-field magnet matrix and a triangular single moving part that carries three three-phase permanent-magnet planar-levitation-motor armatures. Since only a single levitated moving part, namely the platen, generates all required fine and coarse motions, this positioning system is reliable and potentially low-cost. The three planar levitation motors based on the Lorentz force law not only produce the vertical force to levitate the triangular platen but also control the platen's position and orientation in the horizontal plane. The main contribution of this paper is that all 6-DOF motions are solely controlled by magnetic forces without any other means to support the platen's weight against gravity, and the most suitable controller of the magnetic levitation system was designed and implemented. The platen can be regarded as a pure mass, and the spring and damping effects are neglected except for the vertical directions. Single-input single-output digital lead-lag controllers were designed and implemented on a digital signal processor. This 6-DOF fully magnetically levitated positioner has a total mass of 5.91 kg and exhibits a 120×120 mm maximum travel range. The position resolution of 20 nm and position noise of 10-nm root mean square are demonstrated. The positioner has sub-microradian angular resolution in about the x, y, and z-axes. A maximum velocity of 24.8 mm/s in y is achieved. This single-moving-part maglev positioner structure is highly suitable for semiconductor manufacturing applications such as wafer steppers. Several experimental motion profiles are presented to demonstrate the maglev stage's capability of accurately tracking any planar and three-dimensional paths.

주사 현미경용 평면 스캐너 Part 2 : 정 · 동 특성 평가

This paper shows experimental evaluation results of the nano-positioning planar scanner used in the scanning probe microscope. The planar scanner is composed of flexure guides, piezoelectric actuators and feedback sensors as like explained in detail in Ref. (5). First, the fabrication methods were explained. Second, as the static Properties of the Planar scanner. we evaluated the maximum travel range & crosstalk. Also, we presented the correcting method for crosstalk using electric circuits finally. as the dynamic properties of the planar scanner, we evaluated the first resonant frequency. Also, we presented the actual AFM(atomic force microscope) imaging results with up to 2Hz imaging scan rate. Experimental results show that properties of the proposed planar scanner are well enough to be used in SPM applications like AFM.

주사 현미경용 평면 스캐너 Part 1 :설계 및 정 · 동특성 해석

This paper shows a method for design of the nano-positioning planar scanner used in the scanning probe microscope. The planar scanner is composed of flexure guides, piezoelectric actuators and feedback sensors. In the design of flexure guides, the Castigliano`s theorem was used to find the stiffness of the guide. The motion amplifying mechanism was used in the piezoelectric actuator to achieve a large travel range. We found theoretically the travel range of the total system and verified using the commercial FEM(finite element method) program. The maximum travel range of the planar scanner is above than 140 m. The 3 axis positioning capability was verified by the mode analysis using the FEM program.

Absolute interferometric distance measurement using a FM-demodulation technique

We propose an interferometric method for measuring absolute distances larger than the wavelength. A laser diode is used as a light source. The principle of operation is based on multiple-wavelength interferometry that uses a modulated light source. This method uses the fact that the wavelength of light emitted by the laser diode can be varied by means of the injection current. The modulation of the injection current in combination with the optical heterodyne technique causes a high-frequency phase-modulated detector signal. The phase deviation of the signal is a measure of the optical path difference in the interferometer. By FM demodulation of the detector output with a phase-locked loop demodulator, the optical path difference can be determined directly without the classical ambiguity problem of interferometry. The measuring range in the experiments was limited to 50 mm by the maximum travel range of the used specimen translation stage. Because of the inherent light sensitivity of the method described, the rangefinder can be used for three-dimensional profile measurements on a wide variety of objects, even on diffuse scattering surfaces.

Decomposition constant of polonium: E. v. Schweidler ( Verh. Deutch. Phys. Ges., xiv, 536)

Laser Texturing and Laser Engraving of free form surfaces are interesting alternative to EDM and micro milling in the fabrication of moulds and dies. The material removal rate of this process is typically very low and the maximum working area is limited by the maximum travel range of the galvanometric scanning head and also by the maximum deflection of the scanner or the surface curvature. As a consequence, in order to manufacture large or free form surfaces, a set of placements of the scanning head respect to the work piece must be calculated and controlled by the CNC.The number of these placements can be quite high due the small amount of material removed in each of them and the non-operative time spent to move the scanning head can be relevant compared to the overall time. In this work a method based on the solution of the Traveling Salesman Problem is proposed with the aim to optimise the number of displacements of the scanning head and generally in order to reduce the number of movement of the numerically controlled axes.The method that takes into account both the architecture and the dynamic characteristics of a 5 axis CNC system was implemented in the CALM (Computer Aided Laser Manufacturing) software used to program the laser path for part texturing and applied in industrial cases.