Motor Dimensions Research Articles

Analysis of the Selected Design Changes in a Wheel Hub Motor Electromagnetic Circuit on Motor Operating Parameters While Car Driving

The drive system of an electric car must meet road requirements related to overcoming obstacles and driving dynamics depending on the class and purpose of the vehicle. The driving dynamics of modern cars as well as size and weight limitations mean that wheel hub motors operate with relatively high current density and high power supply frequency, which may generate significant power losses in the windings and permanent magnets and increase their operating temperature. Designers of this type of motor often face the need to minimize the motor’s weight, as it constitutes the unsprung mass of the vehicle. Another limitation for motor designers is the motor dimensions, which are limited by the dimensions of the rim, the arrangement of suspension elements and the braking system. The article presents two directions in the design of wheel hub motors. The first one involves minimizing the length of the stator magnetic core, which allows for shortening of the axial dimension and mass of the motor but involves increasing the thermal load and the need for deeper de-excitation. The second one involves increasing the number of pairs of magnetic poles, which reduces the mass, increases the internal diameter of the motor and shortens the construction of the fronts, but is associated with an increase in the motor operating frequency and increased power losses. Additionally, increasing the number of pairs of magnetic poles is often associated with reducing the number of slots per pole and the phase for technological reasons, which in turn leads to a greater share of spatial harmonics of the magnetomotive force in the air gap and may lead to the generation of higher power losses and higher operating temperatures of permanent magnets. The analysis is based on a simulation of the motor operation, modeled on the basis of laboratory tests of the prototype, while the car is driving in various driving cycles.

Current investigation of neurocognitive functioning in preschool children with cancer: A cross-sectional study from western China.

Cancer and its treatments may cause neurocognitive impairments in preschool children, but there is limited research on the neurocognitive outcomes of this population. This study, which assessed the neurocognitive function of preschool children with cancer and analyzed various influencing factors of neurocognitive functioning, is of significant importance. We aimed to investigate neurocognitive function and related risk factors in preschool children with cancer to inform preventive and intervention strategies. From September 2023 to May 2024, we recruited 100 preschool children with cancer. The Chinese version of the Ages & Stages Questionnaires, the Spence Preschool Anxiety Scale Chinese Version, and the Sleep Disturbance Scale for Children were used to collected data. Binary logistic stepwise regression analysis was used to explore the influencing factors of neurocognitive function in preschool children with cancer. 49% of the preschool children with cancer had abnormalities in at least one neurocognitive dimension. The majority of children had abnormalities in gross motor dimension, accounting for 30%, which was related to age and frequency of participation in neurocognitive activities. Communication dimension was related to father's education level, dietary habit, and frequency of participation in activities. Fine motor dimension was associated with age, sex, and father's education level. Problem-solving dimension was associated with age and dietary habit. Personal-social dimension was related to age and radiotherapy. Nearly half of preschool children with cancer experienced neurocognitive impairment. The Chinese version of the Ages & Stages Questionnaires is a simple and effective tool for screening children with possible neurocognitive impairment. It was found that children's neurocognitive function was significantly influenced by family environment, dietary habit, cognitive activities, and cancer treatment. Therefore, it is recommended to strengthen family and social support, and to formulate personalized intervention such as cognitive therapy and dietary adjustment based on children's age and family background, which are important for promoting neurocognitive recovery.

Active Brownian motion of emulsion droplets driven by nanoscale effects under laser irradiation

This work presented the results of an experimental study of dynamics of emulsion complex composition droplets under laser irradiation. The oil-in-water emulsion consisted of liquid paraffin droplets containing magnetite nanoparticles and was placed in an aqueous solution of the surfactant. The magnetite nanoparticles had characteristic dimensions of 10−8 m, which correspond to the dimensions of molecular motors in living cells. For all emulsion droplets, motion in transitional and normal diffusive modes was observed. The effective kinetic temperature of emulsion droplets was 3.5 × 103 eV and was exceeded the temperature of thermal motion of the medium molecules, 0.03 eV. Experimentally observed active Brownian motion of emulsion droplets was a result of intra-droplet motion of magnetite nanoparticles absorbing laser irradiation. Laser irradiation caused the magnetite nanoparticle heating, which generated a thermophoretic force. As a result of viscous friction forces, the nanoparticles transferred momentum to the emulsion droplet, causing its motion.

Evaluación de las dimensiones del desarrollo socioemocional, cognitivo y motor en niños chilenos con Trastorno del Desarrollo del Lenguaje y desarrollo típico: Un estudio analítico

Recent evidence shows that children with Developmental Language Disorder (DLD) may present limitations in areas of development other than language. There are few studies in Spanish-speaking preschoolers that evaluate them, especially in the socioemotional and motor dimensions. The objectives were to compare cognitive, motor, socioemotional and language development between preschoolers with TDL and typical development (TD) and to correlate their language skills with the rest of the dimensions. Forty children with a mean age of 56 months were divided into two groups: 20 with TDL and 20 with TD. They were compared using the Test of Infant Learning and Development (TADI), and it was found that children with TDL performed significantly worse in all scales. When studying the correlations, the relationship between motor skills and receptive grammar in both samples stands out. The findings suggest the need for an interdisciplinary approach under an integrative vision of development that promotes the well-being of these children.

Tablet-based Rey–Osterrieth Complex Figure copy task: a novel application to assess spatial, procedural, and kinematic aspects of drawing in children

The paper-and-pencil Rey–Osterrieth Complex Figure (ROCF) copy task has been extensively used to assess visuo-constructional skills in children and adults. The scoring systems utilized in clinical practice provide an integrated evaluation of the drawing process, without differentiating between its visuo-constructional, organizational, and motor components. Here, a tablet-based ROCF copy task capable of providing a quantitative assessment of the drawing process, differentiating between visuo-constructional, organizational, and motor skills, is trialed in 94 healthy children, between 7 and 11 years of age. Through previously validated algorithms, 12 indices of performance in the ROCF copy task were obtained for each child. Principal component analysis of the 12 indices identified spatial, procedural, and kinematic components as distinct dimensions of the drawing process. A composite score for each dimension was determined, and correlation analysis between composite scores and conventional paper-and-pencil measures of visuo-constructional, procedural, and motor skills performed. The results obtained confirmed that the constructional, organizational, and motor dimensions underlie complex figure drawing in children; and that each dimension can be measured by a unique composite score. In addition, the composite scores here obtained from children were compared with previsions results from adults, offering a novel insight into how the interplay between the three dimensions of drawing evolves with age.

Comparison of Different MATLAB Environments for Designing DC Motor Main Dimensions

Abstract: DC motor is an important device for various industries due to its variable speed control, efficiency, reliability and versatility. The Design calculations of DC Motor are long and tedious process if done manually. A program can be made in any programming language, but again the program length is large, and it is difficult to understand and summarize the design steps in short. In this paper an effort has been made to understand the Design Procedure of a DC Motor using different MATLAB environments. Design of main dimensions of DC Motor was done in three MATLAB environments. First by writing program in editor file, second using Simulink block sets and lastly by forming MATLAB GUI interface. Comparison between each method is discussed in short.

Design and Optimisation of a 5 MW Permanent Magnet Vernier Motor for Podded Ship Propulsion

The evolution of electric propulsion systems in the maritime sector has been influenced significantly by technological advancements in power electronics and machine design. Traditionally, these systems have employed surface-mounted permanent magnet synchronous motors (PMSMs) in podded configurations. However, the advent of permanent magnet Vernier motors (PMVMs), which leverage magnetic gearing effects, presents a novel approach with promising potential. This study conducts a comparative analysis between PMVMs and conventional PMSMs at a power level of 5 MW for podded ship propulsion, with a particular focus on the impact of gear ratios (Gr). An objective function was developed that integrates motor dimension constraints and the power factor (PF), a critical yet frequently neglected parameter in existing research. The findings indicate that PMVMs with lower Gr have lower mass and cost compared to those with higher Gr and traditional PMSMs, at a PF level of 0.7, which is high for Vernier machines. Moreover, PMVMs with lower Gr achieve efficiencies exceeding 99%, outperforming both their higher Gr counterparts and conventional PMSMs. The superior performance of PMVMs is attributed to lower current density and reduced copper loss, which contribute to their enhanced thermal performance. These details are elaborated on further in the paper. Consequently, these findings suggest that PMVMs with lower Gr are particularly well suited for high-power maritime propulsion applications, offering advantages in terms of compactness, efficiency (EF), cost-effectiveness, and thermal performance.

Psychomotor Therapy Using the Body Schema for the Intellectually Disabled at the A.D.A.R-Tubahoze Centre

This study is the preliminary research focused on psychomotor therapy and body schemas for the intellectually disabled, hence the motor dimension with a test of balance, coordination and jumping in the pre-test and post-test of a BPM measurement at 60, 90 and 120 (BPM) with the YO and YC. The cognitive dimension with, for example, the Berces and Lezine test of body control and latero-spatial organization, the Piaget and Head tests of gesture imitation and latero-spatial organization. The affective dimension revolving around self-esteem was measured with the self-perception profile for adults with intellectual disabilities (SPPD) on physical appearance, athletic competence and psychomotor competence. At the end of the verification of research question and using methodological approach adopted on the present study on the motor dimension, the cognitive dimension and the affective dimension; it was found that with the motor dimension on the balance test, a trend on the performance of our intellectually disabled patients from A.D.A.R-Tubahoze centre during the psychomotor therapy sessions was tested positive in the post-test compared to the pre-test (BYO and BYC).With regard to the coordination test (CYO and CYC) at post-test and pre-test, the statistical frequencies with overall averages show that our intellectually impaired patients tended to obtain better results at post-test than at pre-test; this shows a success in the applicability of motor therapy to coordination disorder in intellectually impaired patients. Similarly, a positive performance trend was shown in the results of the jumping test at post-test than at pre-test. The trend in the results of the jump test (JYO and JYC) in the post-test than in the pre-test would have shown a positive result after our therapeutic-motor sessions with the IDs of the A.D.A.R. centre. From the cognitive dimension, using the test of imitation of gestures and lateral-spatial on different movements, has a score of 10 points in the test of imitation of simple gestures of hand movements, it would have been observed in MID patients that the test proved positive; with the Piaget’s Head test of latero-spatial organization administered to MID which was evaluated at a score of 40 points, had as a positive performance to all patients who took this test. The results of our work on the affective dimension of the dominant modality “Rather true”, was observed on items 12, 16, 20 and 24 of self-esteem, with physical appearance vis-à-vis items (5,10,18 and 22) and items 5 and 9 and then items 17, 13 and 1 of athletic competence; from items with a “Rather positive” modality with items 11, 3 and 2 3, 7, 15 and 19 of our MID patients that a positive trend on positive appreciation was satisfactorily observable.

Comprehensive assessment of fine motor movement and cognitive function among older adults in China: a cross-sectional study

BackgroundFine motor skills are closely related to cognitive function. However, there is currently no comprehensive assessment of fine motor movement and how it corresponds with cognitive function. To conduct a complete assessment of fine motor and clarify the relationship between various dimensions of fine motor and cognitive function.MethodsWe conducted a cross-sectional study with 267 community-based participants aged ≥ 60 years in Beijing, China. We assessed four tests performance and gathered detailed fine motor indicators using Micro-Electro-Mechanical System (MEMS) motion capture technology. The wearable MEMS device provided us with precise fine motion metrics, while Chinese version of the Montreal Cognitive Assessment (MoCA) was used to assess cognitive function. We adopted logistic regression to analyze the relationship between fine motor movement and cognitive function.Results129 (48.3%) of the participants had cognitive impairment. The vast majority of fine motor movements have independent linear correlations with MoCA-BJ scores. According to logistic regression analysis, completion time in the Same-pattern tapping test (OR = 1.033, 95%CI = 1.003–1.063), Completion time of non-dominant hand in the Pieces flipping test (OR = 1.006, 95%CI = 1.000-1.011), and trajectory distance of dominant hand in the Pegboard test (OR = 1.044, 95%CI = 1.010–1.068), which represents dexterity, are related to cognitive impairment. Coordination, represented by lag time between hands in the Same-pattern tapping (OR = 1.663, 95%CI = 1.131–2.444), is correlated with cognitive impairment. Coverage in the Dual-hand drawing test as an important indicator of stability is negatively correlated with cognitive function (OR = 0.709, 95%CI = 0.6501–0.959). Based on the above 5-feature model showed consistently high accuracy and sensitivity at the MoCA-BJ score (ACU = 0.80–0.87).ConclusionsThe results of a comprehensive fine-motor assessment that integrates dexterity, coordination, and stability are closely related to cognitive functioning. Fine motor movement has the potential to be a reliable predictor of cognitive impairment.

Timing Patterns in the Extended Basal Ganglia System.

The human brain is a constructive organ. It generates predictions to modulate its functioning and continuously adapts to a dynamic environment. Increasingly, the temporal dimension of motor and non-motor behaviour is recognised as a key component of this predictive bias. Nevertheless, the intricate interplay of the neural mechanisms that encode, decode and evaluate temporal information to give rise to a sense of time and control over sensorimotor timing remains largely elusive. Among several brain systems, the basal ganglia have been consistently linked to interval- and beat-based timing operations. Considering the tight embedding of the basal ganglia into multiple complex neurofunctional networks, it is clear that they have to interact with other proximate and distal brain systems. While the primary target of basal ganglia output is the thalamus, many regions connect to the striatum of the basal ganglia, their main input relay. This establishes widespread connectivity, forming the basis for first- and second-order interactions with other systems implicated in timing such as the cerebellum and supplementary motor areas. However, next to this structural interconnectivity, additional functions need to be considered to better understand their contribution to temporally predictive adaptation. To this end, we develop the concept of interval-based patterning, conceived as a temporally explicit hierarchical sequencing operation that underlies motor and non-motor behaviour as a common interpretation of basal ganglia function.

Identification of Spared and Proportionally Controllable Hand Motor Dimensions in Motor Complete Spinal Cord Injuries Using Latent Manifold Analysis.

The loss of bilateral hand function is a debilitating challenge for millions of individuals that suffered a motor-complete spinal cord injury (SCI). We have recently demonstrated in eight tetraplegic individuals the presence of highly functional spared spinal motor neurons in the extrinsic muscles of the hand that are still capable of generating proportional flexion and extension signals. In this work, we hypothesized that an artificial intelligence (AI) system could automatically learn the spared electromyographic (EMG) patterns that encode the attempted movements of the paralyzed digits. We constrained the AI to continuously output the attempted movements in the form of a digital hand so that this signal could be used to control any assistive system (e.g. exoskeletons, electrical stimulation). We trained a convolutional neural network using data from 13 uninjured (control) participants and 8 tetraplegic participants (7 motor-complete, 1 incomplete) to study the latent space learned by the AI. Our model can automatically differentiate between eight different hand movements, including individual finger flexions, grasps, and pinches, achieving a mean accuracy of 98.3% within the SCI group. Analysis of the latent space of the model revealed that proportionally controllable movements exhibited an elliptical path, while movements lacking proportional control followed a chaotic trajectory. We found that proportional control of a movement can only be correctly estimated if the latent space embedding of the movement follows an elliptical path (correlation =0.73; p <0.001). These findings emphasize the reliability of the proposed system for closed-loop applications that require an accurate estimate of spinal cord motor output.

THE RELATIONSHIP BETWEEN MOTOR ACTIVITY AND EXECUTIVE FUNCTIONS IN THE TEACHING-LEARNING PROCESS: CASE OF 6 - 7 AGED TUNISIAN PUPILS

Considering that the cognitive and motor dimensions of human beings grow together and that primary school age is one of the most important stages of children’s cognitive and motor development, the aim of this study was to investigate the relationship between executive functions and motor activity in the teaching-learning process. Primary school students (N = 40; 6.3 years) participated in this study. They were divided into two groups: an experimental group (20 students) and a control group (20 students). The first group followed a 12-week motors activity program with 5 sessions of 40 minutes per week and the second a regular math sessions program. The results of the experimental group show a clear improvement in most of the study variables. Also, these results highlight the value of actively involving the student in the task and the importance of using active methods in the teaching-learning process.&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt; Article visualizations:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;img src="/-counters-/soc/0036/a.php" alt="Hit counter" /&gt;&lt;/p&gt;

Performance Validation of PM Assisted SynRM and PMSM with Optimized Design for EV Application

This paper presents the comparison of Permanent Magnet-Assisted Synchronous Reluctance Motor (PMASynRM) and Permanent Magnet Synchronous Motor (PMSM) for the same design parameters and the evaluation of various performance parameters based on the Finite Element (FE) Method. FE Analysis is conducted after selecting the optimized design for PMASynRM and PMSM using an FE tool, with loading conditions to determine various performance parameters. This is achieved by maintaining the same motor dimensions and stator parameters while altering the rotor geometry for both motors. The final simulation results are discussed, and other performance parameters are recorded for comparison purposes. A PMASynRM is introduced, in which the problems of Synchronous Reluctance Motor (SynRM) can be eliminated with a permanent magnet in the rotor flux barrier. Due to higher flux barriers in PMASynRM, the reluctance torque is higher than in PMSM. If the magnet is placed very near to the air gap in PMSM, higher magnet torque is achieved, but due to the high reluctance torque in PMASynRM, the electromagnetic torque of PMASynRM is higher compared to PMSM. The research proves that the proposed design of PMASynRM is the best choice for Electric Vehicle (EV) applications. For PMASynRM, the shape of the flux barrier is not possible to change due to the design limitation of the FE software tool. Further analysis can be conducted by changing the shapes of the flux barriers to propose the most effective barriers. Basic theory and FE analysis of conventional PMSM and SynRM are reported in the literature. An optimal design is proposed through comparative analysis for EV applications to find out the best candidate for an EV motor.

Cognitive impairment is associated with gait variability and fall risk in Amyotrophic Lateral Sclerosis.

In amyotrophic lateral sclerosis (ALS), gait abnormalities contribute to poor mobility and represent a relevant risk for falls. To date, gait studies in ALS patients focused on the motor dimension of the disease, underestimating the cognitive aspects. Using a wearable gait analysis device, we compared gait patterns in ambulatory ALS patients with Mild Cognitive Impairment (ALS MCI+; n=18), and without MCI (ALS MCI-; n=24), and healthy individuals (HS; n=16) under two conditions: (1) normal gait (single task), (2) walking while counting backward (dual task). Finally, we examined if the occurrence and number of falls in the three months following the baseline test were related to cognition. In the single task condition, ALS patients, regardless of cognition, displayed higher gait variability than HS, especially for stance and swing time (p< 0.001). The dual task condition revealed additional differences in gait variability parameters between ALS MCI+ and ALS MCI- for cadence (p=0.005), stance time (p=0.04), swing time (p=0.04) and stability index (p=0.02). Moreover, ALS MCI+ showed a higher occurrence (p=0.001) and number of falls (p<0.001) at the follow-up. Regression analyses demonstrated that MCI condition predicted the occurrence of future falls (β= 3.649 p= 0.01) and, together with executive dysfunction, was associated with the number of falls (cognitive impairment: β= 0.63; p < 0.001; executive dysfunction: β= 0.39; p= 0.03), regardless of motor impairment at clinical examination. In ALS, MCI is associated with exaggerated gait variability and predicts the occurrence and number of short-term falls. This article is protected by copyright. All rights reserved.

Modeling and analysis of oil frictional loss in wet-type permanent magnet synchronous motor for aerospace electro-hydrostatic actuator

To improve the power density and simplify the seal structure, the Wet-Type Permanent Magnet Synchronous Motor (WTPMSM) technique has been applied to aerospace Electro-Hydrostatic Actuators (EHA). In a WTPMSM, the stator and the rotor are both immersed in the aviation hydraulic oil. Although the heat dissipation performance of the WTPMSM can be enhanced, the aviation hydraulic oil will cost an extra oil frictional loss in the narrow airgap of the WTPMSM. This paper proposes an accurate oil frictional loss model for the WTPMSM, in which the wide speed range (0–20 kr/min) and the narrowness of the airgap (0.5–1.5 mm) are its features. Firstly, the mechanism of the oil frictional loss in the airgap of the WTPMSM is revealed. Then an accurate oil frictional loss model is proposed considering the nonlinear influence caused by the Taylor vortex. Furthermore, the influence of motor dimensions on oil frictional loss is analyzed. Finally, the proposed oil frictional loss model is verified by experiments, which provides a guideline for engineers to follow in the WTPMSM design.

0894 Impulsivity across early stages of synucleinopathy: from high-risk relatives, REM sleep behavior disorder to Parkinson’s disease

Abstract Introduction Increased impulsivity is a common neuropsychiatric feature in patients with Parkinson’s disease (PD), especially attributed to the use of dopaminergic medications. Interestingly, emerging evidence suggested that impulsivity had changed in drug-naïve PD patients. However, it remains unclear whether impulsivity has been altered in prodromal stage of PD, namely isolated rapid eye movement sleep behavior disorder (iRBD) and their high-risk relatives. Methods This was a cross-sectional study with four groups of subjects, including early drug-naive PD patients, patients with iRBD and their first-degree relatives (iRBD-FDRs, a high-risk group with potential prodromal RBD features), and controls. A panel of neuropsychological computerized tasks, including go/no-go task, four-choice serial reaction time task (4CSRTT), beads task, balloon analogue risk task (BART) and delay/effort discounting task, would measure various dimensions of motor and decisional impulsivity. Results A total of 331 subjects were recruited, including 27 early drug-naïve PD patients (mean age ± SD: 70.1 ± 5.8 years, 77.8% man), 152 iRBD patients (67.2 ± 6.6 years, 77.6% man), 68 iRBD-FDRs (63.2 ± 6.4 years, 51.5% man), and 84 controls (67.4 ± 8.1years, 61.9% man). Early drug-naïve PD and iRBD patients had fewer numbers of extracted beads in beads task 1 (P&amp;lt; 0.001) and task 2 (P&amp;lt; 0.001) in making decisions and fewer numbers of pumps of unexploded blue balloons in BART (P&amp;lt; 0.001) than controls and iRBD-FDRs, suggesting a higher level of reflection impulsivity and a lower level of risk taking, respectively. In addition, early drug-naïve PD and iRBD patients had more no-go errors in go/no-go task (P=0.023), suggesting a marginally lower level of response inhibition in PD and iRBD groups. Early drug-naïve PD and iRBD patients had more premature responses in 4CSRTT than iRBD-FDRs (P=0.008). The delay and effort discounting indexes were comparable among four groups. Conclusion While risk taking and response inhibition decreased, reflection impulsivity actually increased in iRBD and drug-naïve PD patients. These novel findings indicated that a complex construct of altered impulsivity has already occurred at the earlier stage (at iRBD) of α-synucleinopathy, which will have implications for pathophysiology and clinical management. Support (if any) This study has been supported by the General Research Fund (14116119).

Physical capacity tests as a complement in the evaluation of the level of disability in women with fibromyalgia: A cross-sectional study.

The association between motor capacity and the level of disability in patients with fibromyalgia remains underexplored. This study aims to explore the association between physical capacity tests explored in the consultation and the level of disability in women with fibromyalgia. There were 484 women diagnosed with fibromyalgia who were evaluated with 7 physical capacity tests: 10-m walk, 2-minute walk, 5-repetition getting up from a chair and sitting (G&S), 30-second chair stand, monopodal balance (right and left), and up-and-go. Functional performance was assessed with the Revised Fibromyalgia Impact Questionnaire (FIQR). Evaluation of the association between the physical capacity tests and the FIQR was initially performed using a principal component analysis (PCA). Subsequently, agglomerative hierarchical clustering (AHC) was performed in order to characterize groups of patients. Results show than FIQR and the tests 10-m walk, 2-minute walk, 5-repetition G&S, 30-second chair stand, and up-and-go test were correlated. The results of the AHC determined 3 groups of patients mainly on one motor dimension with significant differences in both the FIQR and the physical capacity tests retained in the PCA (P < 0.001 for all). The application of these physical tests is simple, fast and can be a complement to the FIQR questionnaire when determining the level of disability of patients with fibromyalgia, in addition to providing information on the evolution of the patients when these tests are administered in the clinical consultation.

A compact, friction self-matching, non-inertial piezo motor with scanning capability

Maintaining friction matching is the core issue for non-inertial piezo motors (PMs); this challenge severely limits their application in complex conditions such as variable temperature environments. To address this issue, a compact, optimal friction self-matching PM with non-inertial driving is reported in this paper. The motor is implemented with a narrow 5.5 mm-outer diameter piezoelectric scanner tube (PST) whose outer electrode is equally divided into two independently controllable PSTs. The PST, divided into two parts, clamps a sapphire rod between dual sapphire ball structures at both ends and an elastically supported sapphire ball at the centre. The device features a balanced normal force distribution scheme that allows friction forces acting on the sapphire rod at both ends and on the intermediate section to be approximately equal along the axial direction of the PST, achieving automatic optimal matching of friction, then it can operate like an inchworm motor. The feasibility of this scheme is verified by testing with a low threshold voltage down to 35 V at room temperature and 160 V at liquid nitrogen temperature. The motor dimensions are 5.5 mm × 5.5 mm ×35 mm (length × width × height). At room temperature, step size ranges from 0.1 μm to 1 μm. It has a maximum stroke about 5 mm and a maximum load of 40 g. This PM’s extreme compactness, low machine tolerance requirements, and smooth sequence make it ideally suited for building superior quality, atomically resolved scanning probe microscopy devices compatible with narrow spaces and extreme conditions.

МОДЕЛИРОВАНИЕ СОБСТВЕННЫХ ЧАСТОТ И АМПЛИТУДЫ ВЫНУЖДЕННЫХ КОЛЕБАНИЙ ВЕРТИКАЛЬНО-ФРЕЗЕРНОГО СТАНКА

The article demonstrate the technique for modeling the form of natural oscillations, as well as the amplitude and mode of forced oscillations of the HAAS VF-1 vertical milling machine. As initial data, a publicly available 3D model of load-bearing elements, information on the mass and dimensions of the spindle motor are used. In preparation for the simulation, the original solid model is idealized by removing small chamfers, fillets, and small diameter holes. Movable joints with linear rolling guides and ball bearings are replaced by rigid joints, since vibration damping in these units is not considered. During the first simulation, ten natural frequencies with the largest values of the oscillation amplitude are obtained. The second simulation shows, the influence of the spindle drive layout (coaxial installation of the electric motor with the spindle through a cam clutch or connection using a toothed belt transmission) and additional devices for dissipating vibration energy (mass and structural dampers in the form of structural elements articulated through plastic bushings) is revealed by the magnitude of forced steady-state oscillations that may occur during the processing of the part.

Sizing of the Motor Geometry for an Electric Aircraft Propulsion Switched Reluctance Machine Using a Reluctance Mesh-Based Magnetic Equivalent Circuit

The switched reluctance motor (SRM) is a promising candidate for electric propulsion systems. In the design process of an SRM, the motor geometry needs to be determined. Using the finite element method (FEM) might be time-consuming for the sizing of the motor geometry. As an alternative, electromagnetic models based on a magnetic equivalent circuit (MEC) can be utilized for the sizing of an SRM. MEC models require fewer computational resources and can help determine the electromagnetic performance with reasonable accuracy. Using the conventional MEC method for SRM sizing might be challenging since the flux pattern inside the motor should be changed for different motor dimensions. In order to address this challenge, this paper applies a reluctance mesh-based MEC technique to determine the geometry of a three-phase 12/16 SRM for a high-lift motor in the NASA Maxwell X-57 electric aircraft. A comprehensive reluctance mesh-based MEC model is developed for this purpose. Both the static and dynamic characteristics of the SRM geometry are evaluated using the reluctance mesh-based MEC method. The determined geometry is verified using the results computed from FEM.