Linear Stepper Motor Research Articles

Optimizing anterior urethral stricture assessment: leveraging AI-assisted three-dimensional sonourethrography in clinical practice.

This investigation sought to validate the clinical precision and practical applicability of AI-enhanced three-dimensional sonographic imaging for the identification of anterior urethral stricture. The study enrolled 63 male patients with diagnosed anterior urethral strictures alongside 10 healthy volunteers to serve as controls. The imaging protocol utilized a high-frequency 3D ultrasound system combined with a linear stepper motor, which enabled precise and rapid image acquisition. For image analysis, an advanced AI-based segmentation process using a modified U-net algorithm was implemented to perform real-time, high-resolution segmentation and three-dimensional reconstruction of the urethra. A comparative analysis was performed against the surgically measured stricture lengths. Spearman's correlation analysis was executed to assess the findings. The AI model completed the entire processing sequence, encompassing recognition, segmentation, and reconstruction, within approximately 5min. The mean intraoperative length of urethral stricture was determined to be 14.4 ± 8.4mm. Notably, the mean lengths of the urethral strictures reconstructed by manual and AI models were 13.1 ± 7.5mm and 13.4 ± 7.2mm, respectively. Interestingly, no statistically significant disparity in urethral stricture length between manually reconstructed and AI-reconstructed images was observed. Spearman's correlation analysis underscored a more robust association of AI-reconstructed images with intraoperative urethral stricture length than manually reconstructed 3D images (0.870 vs. 0.820). Furthermore, AI-reconstructed images provided detailed views of the corpus spongiosum fibrosis from multiple perspectives. The research heralds the inception of an innovative, efficient AI-driven sonographic approach for three-dimensional visualization of urethral strictures, substantiating its viability and superiority in clinical application.

Research on Micro-/Nano-Positioning System Driven by a Stepper Motor

To achieve cost-effective micro-/nano-displacement adjustment, this paper integrates the advantages of flexible hinge micro-/nano-displacement transmission. A linear stepper motor is utilized as the driving component to design and develop a high-precision, low-cost micro-/nano-positioning system. The structure, design, and working principles of the micro-/nano-positioning platform are introduced. The scaling factor model between micro-positioning platforms and nano-positioning platforms is analyzed. Static and dynamic models of flexible mechanisms have been established. The dimensions of the mechanical structure and the selection of motors are determined. The mechanical characteristics of the micro-/nano-positioning platform are validated through finite element analysis. To address the characteristic of increasing loads during the transmission process, an intelligent control system based on current feedback is designed and developed. The integration of drive and control provides a high level of system integration. Finally, experimental calibration was conducted to test the motion characteristics of the linear stepper motor-driven micro-/nano-positioning platform. It achieved a minimum displacement control resolution of 100 nm and demonstrated a certain level of stability.

Analyzing the Design and Performance of a DC Linear Stepper Motor

This paper describes the design and modelling of a DC linear stepper motor (DLSM), to investigate the air-gap magnetic flux density and the static features of the thrust force under the DC current excitation condition, while taking the nonlinear properties of iron materials used into account. A Finite Element Method (FEM) study utilizing software called a “MagNet” was employed to model and construct a linear DC motor. The thrust force, air-gap flux density, and static thrust force at various airgaps were compared in simulation and real time. The result showed that the magnetic flux density presents a sinusoidal shape in both the simulation and measurement, where the peak error value was around 7.14%. A comparison was made with thrust force, as the armature current has different values; the results show that the difference between the experimental and computed peak value was 8.07%, while the error between the measured and simulated value was 5.02% when the thrust force was measured at different air gap lengths.

Digital Control Method and Performance Analysis of the Double-Compound Axial Piston Pump.

The flow control range of the double-compound axial piston pump with the traditional mechanical-hydraulic feedback servo control is limited and the accuracy is poor. Accordingly, this paper proposes a digital control scheme and its control strategy using a linear stepper motor direct drive servo valve for the precise control and double pumps cooperation of the double-compound axial piston pump. A numerical model of the digital control double-compound axial piston pump is established, and the validity of the model is verified by experimental tests. The performance advantages of the digital control method relative to the mechanical-hydraulic feedback servo control method are analyzed, as is the performance of the control strategy for double pumps. The results show that the digital control method can achieve a wider range of flow control than the traditional mechanical-hydraulic feedback servo control method and avoid the torque impact on the prime mover caused by the active control. The combination of the flow control and the power control including four control modes can meet the performance requirements of the double-compound axial piston pump. The highest priority is given to the energy-saving control, which can reduce the displacement of the main pump in the nonworking state to reduce the additional power loss. The study provides a basis for the accurate matching and optimization of power to load and flow to operating speed of the double-compound axial piston pump.

Design and implementation of DC linear actuator and stepper motor for remote control of the driverless tractor robot

This research was to propose the DC linear actuators and a stepper motor as mechanical drive systems such as brake pedal, clutch pedal, forward-reverse gearshift, gear position selection, tail-lifting system to lift the chemical tank, and the speed selection system of power take-off (PTO). The DC linear actuators were used instead of the muscles, arms, and legs of the human being. The stepper motor was used to control the steering direction of a driverless tractor robot. The control was based on the programmable logic controller and radio remote control for the driverless tractor robots. Both MATLAB/Simulink simulation and experimental results were the validation and satisfactorily achieved. The test results of the driverless tractor robot in spraying water on a football field were satisfactory steering response and rapid braking.

Assessment of photoacoustic tomography contrast for breast tissue imaging using 3D correlative virtual histology

Current breast tumor margin detection methods are destructive, time-consuming, and result in significant reoperative rates. Dual-modality photoacoustic tomography (PAT) and ultrasound has the potential to enhance breast margin characterization by providing clinically relevant compositional information with high sensitivity and tissue penetration. However, quantitative methods that rigorously compare volumetric PAT and ultrasound images with gold-standard histology are lacking, thus limiting clinical validation and translation. Here, we present a quantitative multimodality workflow that uses inverted Selective Plane Illumination Microscopy (iSPIM) to facilitate image co-registration between volumetric PAT-ultrasound datasets with histology in human invasive ductal carcinoma breast tissue samples. Our ultrasound-PAT system consisted of a tunable Nd:YAG laser coupled with a 40 MHz central frequency ultrasound transducer. A linear stepper motor was used to acquire volumetric PAT and ultrasound breast biopsy datasets using 1100 nm light to identify hemoglobin-rich regions and 1210 nm light to identify lipid-rich regions. Our iSPIM system used 488 nm and 647 nm laser excitation combined with Eosin and DRAQ5, a cell-permeant nucleic acid binding dye, to produce high-resolution volumetric datasets comparable to histology. Image thresholding was applied to PAT and iSPIM images to extract, quantify, and topologically visualize breast biopsy lipid, stroma, hemoglobin, and nuclei distribution. Our lipid-weighted PAT and iSPIM images suggest that low lipid regions strongly correlate with malignant breast tissue. Hemoglobin-weighted PAT images, however, correlated poorly with cancerous regions determined by histology and interpreted by a board-certified pathologist. Nuclei-weighted iSPIM images revealed similar cellular content in cancerous and non-cancerous tissues, suggesting malignant cell migration from the breast ducts to the surrounding tissues. We demonstrate the utility of our nondestructive, volumetric, region-based quantitative method for comprehensive validation of 3D tomographic imaging methods suitable for bedside tumor margin detection.

Research stand for microplasma surface treatment of materials at atmospheric pressure

A research stand for microplasma treatment of object surfaces with the ability to move the discharge zone along the object using a program-controlled linear stepper motor has been developed. The design of the stand allows the use of different types of plasma generation systems, as well as processing with feeding of various gases such as air, nitrogen, oxygen, etc. into the discharge zone. The research bench is equipped with measuring equipment for monitoring the electrical and physical characteristics of the discharge (digital oscilloscopes, optical emission spectrometer, air ion meter, etc.). A microhardness tester, goniometer, interference microscope, tribometer, tensile testing machine, etc. can be used to further evaluate the quality and characteristics of the treated surfaces. Examples of the electrical characteristics of discharge devices tested as part of the research stand, optical emission spectroscopy of plasma, and results of measurements of the contact angle of treated objects surfaces are given.

Development automated capture device for picking apples

In the system of the mechanized process of cultivation of fruit crops, harvesting is an important final stage, which requires the development of new, convenient, including those that do not damage the fruit, automated technical devices. As a result of a series of experiments, the operability of the developed automated fruit picking device was confirmed, it gently captures the fruit and reliably holds it. The operating modes of the automated device for picking fruits have been established. The following characteristics of the device for picking fruits were revealed: the time for a complete capture of the apple is from 1.5 seconds to 2 seconds, depending on their size, the maximum size of the captured apple is 85x80 mm, the maximum weight of the captured apple is 400 g. The permissible pressure of the paws of the device on the fruit is determined ... It was found that with the force of the linear stepper motor on the pusher in 8N, the safety of the apple is ensured with minimal damage, while the apple is securely fixed in the capture paws.

Nondestructive Determination of Fruit Surface Area Using Archimedean Buoyancy

Estimates of fruit surface area are often required in physiological and technological studies. The objective was to establish a procedure to accurately quantify the fruit surface area based on Archimedean buoyancy measurements. The setup comprised a fixed, linear stepper motor mounted with its spindle vertical and aligned directly above the pan of an electronic balance. A fruit was clamped to the motor spindle and a beaker of water rested on the balance pan. When the motor was activated, the fruit was progressively immersed, stepwise, in the water. Each vertical displacement step increased the buoyant upthrust on the fruit, which was opposed by a corresponding increase in the downthrust on the balance. Pairs of the step displacement length (mm) and corresponding buoyancy increment (g) values were recorded in an MS Excel (Microsoft, Redmond, WA) spreadsheet using Arduino components. Each displacement step immersed another “virtual slice” of the fruit in the water. From each pair of known displacement–buoyancy measurements, the volume (mL) of that slice could be calculated with high precision based on the known density of the liquid (g·mL−1). With the fruit orientated so that its morphological “long” axis was vertical, for most fruitcrop species, the slice can be assumed to have a circular cross-section. Hence, the slice can be analyzed geometrically as a truncated cone of known height (mm) and known volume (mL). Therefore, the surface area of its outer face is calculable. The surface area of the whole fruit was calculated as the cumulative total of the surface areas of all steps (virtual slices). The procedure was evaluated and calibrated using stainless-steel spheres in place of the fruit. However, the measured surface area was slightly greater than that calculated for a sphere. The calculated and measured areas did not differ by more than 1.7%. The surface area determinations were highly reproducible (cv = 0.95%). The magnitude of the displacement steps affected the variability of the surface area measurements. Increasing the step displacements decreased the measurement variability, but there were no significant effects on the surface area measurements of the surface tension of the liquid or of the wettability of the surface of the fruit or the stainless-steel subject. Using stainless-steel spheres (diameter, 5–60 mm) or rubber truncated cones (mean diameter, 8–45 mm) revealed an excellent agreement between the measured and calculated surface areas. Using tomatoes, grapes, blueberries, and strawberries, the measured surface areas were in excellent agreement with those calculated from the fruit dimensions and appropriate geometrical assumptions. The results demonstrate that the surface areas of fruit with approximately circular cross-sections normal to their morphological axes can be determined with high accuracy and reproducibility using Archimedean buoyancy.

Design and Modelling of a Minimally Actuated Serial Robot

In this letter we present a minimally actuated overly redundant serial robot (MASR). The robot is composed of a planar arm comprised of ten passive rotational joints and a single mobile actuator that travels over the links to reach designated joints and rotate them. The joints remain locked, using a worm gear setup, after the mobile actuator moves to another link. A gripper is attached to the mobile actuator thus allowing it to transport objects along the links to decrease the actuation of the joints and the working time. A linear stepper motor is used to control the vertical motion of the robot in 3D space. Along the letter, we present the mechanical design of the robot with 10 passive joints and the automatic actuation of the mobile actuator. We also present an optimization algorithm and simulations designed to minimize the working time and the travelled distance of the mobile actuator. Multiple experiments conducted using a robotic prototype depict the advantages of the MASR robot: its very low weight compared to similar robots, its high modularity and the ease of replacement of its parts since there is no wiring along the arm, as shown in the accompanying video.

Automatic Food Processor

In the current scenario the advent of automation technology is limited to industrial use only. This proposed system of Automatic food processor based on PLC and SCADA software is designed to cook food automatically as required by the user. This PLC based automated system is already pre-programmed to do the operations and the output is obtained. An HMI interface is available to the user to select the quantity and give their preferences. A water level sensor is placed in the tank which monitors the water level present. The ingredients necessary are added with the help of a linear stepper motor and solenoid valves. PLC is used to control the working of the whole system and SCADA is one of the emerging technologies which is used for complete monitoring.

Hybrid controller for precision positioning application

In this paper, a precision positioning hybrid controller for long travel distance with submicron/nanometer resolution and accuracy is designed and developed. A hybrid control algorithm is designed to combine the coarse positioning system and a precision positioning system. The coarse positioning system consists of a linear stepper motor and coarse positioning controller, which is designed by microstepping with proportional-integral (PI) current feedback (MSPICF) control. In the precision positioning system, a piezoelectric actuator (PZA) is used. The mathematical model of the PZA has been represented by 2nd order mass-spring system with the Dahl hysteresis model and the model parameters are estimated by an autoregressive with exogenous terms (ARX) model identification technique using the input–output experimental data. The precision positioning controller designed by feedforward (FF) control which is the inverse of the mathematical model of the PZA and feedback (FB) control. The coarse, precision and hybrid controller is implemented using a low-cost DsPIC30F4012 microcontroller. Experiments have been performed to evaluate the performance of the controller.

Unique spectral signature of human cutaneous squamous cell carcinoma by photoacoustic imaging.

Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with metastatic potential. To reduce reoperations due to nonradical excision, there is a need to develop a technique for identification of tumor margins preoperatively. Photoacoustic (PA) imaging is a novel imaging technology that combines the strengths of laser optics and ultrasound. Our aim was to determine the spectral signature of cSCC using PA imaging and to use this signature to visualize tumor architecture and borders. Two-dimensional PA images of 33 cSCCs and surrounding healthy skin were acquired ex vivo, using 59 excitation wavelengths from 680 to 970 nm. The spectral response of the cSCCs was compared to healthy tissue, and the difference was found to be greatest at wavelengths in the range 765 to 960 nm (P < .05). Three-dimensional PA images were constructed from spectra obtained in the y-z plane using a linear stepper motor moving along the x-plane. Spectral unmixing was then performed which provided a clear three-dimensional view of the distribution of tumor masses and their borders.

Super Wide-Field Photoacoustic Microscopy of Animals and Humans In Vivo

Acoustic-resolution photoacoustic micro-scopy (AR-PAM) is an emerging biomedical imaging modality that combines superior optical sensitivity and fine ultrasonic resolution in an optical quasi-diffusive regime (~1-3 mm in tissues). AR-PAM has been explored for anatomical, functional, and molecular information in biological tissues. Heretofore, AR-PAM systems have suffered from a limited field-of-view (FOV) and/or slow imaging speed, which have precluded them from routine preclinical and clinical applications. Here, we demonstrate an advanced AR-PAM system that overcomes both limitations of previous AR-PAM systems. The new AR-PAM system demonstrates a super wide-field scanning that utilized a 1-axis water-proofing microelectromechanical systems (MEMS) scanner integrated with two linear stepper motor stages. We achieved an extended FOV of 36 ×80 mm2 by mosaicking multiple volumetric images of 36 ×2.5 mm2 with a total acquisition time of 224 seconds. For one volumetric data (i.e., 36 ×2.5 mm2), the B-scan imaging speed over the short axis (i.e., 2.5 mm) was 83 Hz in humans. The 3D volumetric image was also provided by using MEMS mirror scanning along the X-axis and stepper-motor scanning along the Y-axis. The super-wide FOV mosaic image was realized by registering and merging all individual volumetric images. Finally, we obtained multi-plane whole-body in-vivo PA images of small animals, illustrating distinct multi-layered structures including microvascular networks and internal organs. Importantly, we also visualized microvascular networks in human fingers, palm, and forearm successfully. This advanced MEMS-AR-PAM system could potentially enable hitherto not possible wide preclinical and clinical applications.

Quantification of murine cardiac hypertrophy using 4D ultrasound

Cardiac hypertrophy is abnormal thickening, followed by dilation, of the heart which can lead to congestive heart failure. Herein, we use a mouse model of hypertrophy to explore the relationship between in vivo strain and the resultant hypertrophic state. To do so, osmotic pumps containing saline (n = 5) or angiotensin II (AngII; n = 10) were surgically implanted into the dorsal flank of C57BL/6J mice. AngII increased blood pressure and cardiac afterload, causing myocardial hypertrophy. Mice were imaged weekly using a VisualSonics Vevo2100 ultrasound system with a MS550D transducer (40 MHz center frequency) to collect ECG-gated Kilohertz Visualization data. In combination with a linear stepper motor, we also collected four dimensional (4D) cardiac data (3D + time). Two weeks post-surgery, pumps were removed from a subset of mice to assess the heart’s ability to repair itself post-insult (n = 5). All mice were euthanized at 4 weeks. Standard metrics of left ventricular mass measured via two-dimensional slices of the 4D data indicated significantly increased mass in the AngII mice by day 14. Removal of the pump enabled significant, but partial, recovery. Current work is being performed to calculate strain within the cardiac wall. Ultimately, we aim to determine if increases in in vivo strain precede increases in cardiac mass.

A flexure motion stage system for light beam control

This paper presents the design of an improved tip-tilt-piston compliant/flexure motion stage for steering light beam. The motion stage is actuated by three linear stepper motors in an open-loop control. Using a laser and optical setup, the completed device was tested by making it steer a laser beam, effectively demonstrating its range of movement and level of precision. The testing has proved that the new motion stage system has a maximum bidirectional rotation range of at least 2.89° with a precision and repeatability of 0.0213°, demonstrating a micro-positioning ability.

Design and Control for Linear Machines, Drives, and MAGLEVs—Part I

The 18 papers in this special section focus on the technology of linear electric (electromagnetic)machines (LEMs). LEMs were introduced at the turn of the last century. They have been conceived to convert electrical energy into mechanical energy (or vice versa) as a direct linear motion through electromagnetic forces. LEMs are reversible devices,meaning that they can work as bothmotors and generators. Although feasible, linear alternators are currently explored for limited applications (e.g., Stirling motor). On the contrary, linear motors or actuators are electromagnetic devices capable of producing direct (without any link or interposition) linear motions of the following types: in a unique direction, short-stroke motion, oscillatory motion, and step-by-step motion. Correspondingly, exactly as in the rotating counterpart, different types of linear motors have been devised: linear synchronous motors (LSMs) in its versions with excitation winding, with permanent magnets (PMs) LSMs or without both (linear reluctance motor = LRM), linear induction motors (LIMs), and linear stepper motors.

Rapid Prototyping High-Performance MR Safe Pneumatic Stepper Motors

In this paper, we show that magnetic resonance (MR) safe pneumatic stepper motors can be constructed using rapid prototyping techniques such as 3-D printing and laser-cutting. The designs are lightweight, metal-free, and fully customizable. Besides MR safe robotic systems, other potential applications include high-voltage switchgear and nuclear power plant systems, which also restrict electric actuation. In addition, it can be applied to other actuation systems, where pressurized air is available, and lightweight rapid prototypeable actuators are needed. Five pneumatically driven linear and rotational stepper motors have been developed with forces up to $\text{330 N}$ , torques up to 3.7 N $\cdot$ m, the stepping frequency up to 320 Hz, dimensions ranging from 25 to 80 mm, free of backlash, and power up to 26 W. All five motors are constructed from six 3-D printed parts and four seals, held together by nylon screws or clips. The described stepper motors outperform state-of-the-art plastic pneumatic stepper motor designs, both in specifications and in manufacturability.

Design of pneumatic proportional flow valve type 5/3

In this paper the 5/3-way pneumatic, proportional flow valve was designed and made. Stepper linear actuator was used to move the spool. The valve is controlled by the controlled based on a AVR microcontroller. Virtual model of the valve was created in CAD. The real element was made based on a standard 5/3-way manually actuated valve with hand lever, which was dismounted and replaced by linear stepper motor. All the elements was mounted in a specially made housing. The controller consists of microcontroller Atmega16, integrated circuit L293D, display, two potentiometers, three LEDs and six buttons. Series of research was also conducted. Simulation research were performed using CFD by the Flow Simulation addition to SolidWorks. During the experiments the valve characteristics of flow and pressure was determined.

Stormram 3: A Magnetic Resonance Imaging-Compatible Robotic System for Breast Biopsy

Stormram 3 is a magnetic resonance imaging (MRI)-compatible robotic system that can perform MR-guided breast biopsies of suspicious lesions. The base of the robot measures 160 # 180 # 90 mm, and it is actuated by five custom pneumatic linear stepper motors, driven by a valve manifold outside the Faraday cage of the MRI scanner. All parts can be rapidly prototyped with three-dimensional (3-D) printing or laser cutting, making the design suitable for other applications, such as actuation in hazardous environments. Based on the choice of materials, the robot (with the exception of the needle) is inherently MR safe. Measurements show that the maximum force of the T-49 actuator is 70 N, at a pressure of 0.3 MPa. The Stormram 3 has an optimized repeatability that is lower than 0.5 mm, and it can achieve a positional accuracy on the order of 2 mm.