Electromechanical Systems Research Articles

Design of Human Posture Recognition System Based on Internet of Things Technology and Image Segmentation Algorithm

Abstract To address the problem of the traditional human posture recognition system being easily affected by environmental factors such as noise, a human posture recognition system based on Internet of Things technology and an image segmentation algorithm was designed. To do this, we selected the attitude sensor, designed the attitude sensor structure based on micro electro mechanical system technology, and had a variety of selectable data output modes. A 36 V power supply was selected as the circuit design index to provide sufficient power for the system. The main control chip was designed, and its state information description and external output were installed in a single chip or the same component. The denoising process based on image segmentation algorithm was designed, the error correction model was constructed, the measured values were normalized, and the image segmentation model was constructed. We extracted the node features of human body posture, used the image segmentation algorithm to construct the structure diagram of human body posture nodes, located the local recognition area of the node structure map, and designed the human body posture recognition system. The experimental results show that the designed human gesture recognition system has better effect and better recognition performance.

Analysis of the Phase Voltage of an Induction Motor of an Adjustable Electromechanical System

Analysis of the Phase Voltage of an Induction Motor of an Adjustable Electromechanical System

Nonlinear dynamics analysis of electromechanical planetary gear systems with temperature effects considered

PurposeThe electromechanical planetary transmission system has the advantages of high transmission power and fast running speed, which is one of the important development directions in the future. However, during the operation of the electromechanical planetary transmission system, friction and other factors will lead to an increase in gear temperature and thermal deformation, which will affect the transmission performance of the system, and it is of great significance to study the influence of the temperature effect on the nonlinear dynamics of the electromechanical planetary system.Design/methodology/approachThe effects of temperature change, motor speed, time-varying meshing stiffness, meshing damping ratio and error amplitude on the nonlinear dynamic characteristics of electromechanical planetary systems are studied by using bifurcation diagrams, time-domain diagrams, phase diagrams, Poincaré cross-sectional diagrams, spectra, etc.FindingsThe results show that when the temperature rise is less than 70 °C, the system will exhibit chaotic motion. When the motor speed is greater than 900r/min, the system enters a chaotic state. The changes in time-varying meshing stiffness, meshing damping ratio, and error amplitude will also make the system exhibit abundant bifurcation characteristics.Originality/valueBased on the principle of thermal deformation, taking into account the temperature effect and nonlinear parameters, including time-varying meshing stiffness and tooth side clearance as well as comprehensive errors, a dynamic model of the electromechanical planetary gear system was established.

ВПЛИВ ДИСКРЕТНОГО ХАРАКТЕРУ СИГНАЛУ ШВИДКОСТІ НА ПРОЦЕСИ КЕРУВАННЯ МОМЕНТОМ ВЕКТОРНО-КЕРОВАНОГО АСИНХРОННОГО ДВИГУНА

The paper presents the investigation of the impact of the discrete character of the measured by incremental encoder speed signal on the induction motor torque vector control in traction electrical drive. The study is based on mathemati-cal simulations for a direct vector flux-torque control system which provides direct asymptotic field-orientation, asymp-totic flux-torque trajectory tracking, and asymptotic decoupling of the torque and flux subsystems. The parameters of the induction motor and encoder used in the study correlate with used in the real traction electromechanical systems of trolleybuses. It is shown that introduction of first order filter in the speed measurement channel reduces the induction motor’s current and torque spikes, but leads to an error in torque control and degradation of the rotor flux field-orientation conditions. Combined utilization of filtered and unfiltered speed signal is proposed in order to avoid this disadvantage. Ref. 7, fig. 6.

Experimental Research in Frequency and Time Domain for Electromechanical System with Distributed Parameters in Mechanical Part

Experimental Research in Frequency and Time Domain for Electromechanical System with Distributed Parameters in Mechanical Part

Influence of electrolytic plasma spatial distribution on nanoporous structure etching on 4H-SiC surface

Single-crystal SiC nanoporous structure has important applications in the field of micro electromechanical systems, chemical sensors and biomedical devices. However, SiC exhibits a strong chemical inertness due to the short interatomic distance and high binding energy, making it significantly challenging to fabricate nanoporous structure. Electrolytic plasma-assisted chemical etching (EPACE) based on electrochemical anodic oxidation and high-activity electrolytic plasma etching is an ideal method for SiC nanoporous structure etching. In which, the spatial distribution of electrolytic plasma has an important impact on EPACE performance, such as etching efficiency and stability. In order to analyze the impact mechanism, this paper studies EPACE in tool electrode mounting posture of vertical and horizontal types by visual observation, real-time recording of voltage-current waveforms during processing, and the morphology analysis of SiC nanoporous structure after etching. It can be found that in the vertical etching type, EPACE can proceed stably because the workpiece immersion depth is greater than the bubble accumulation thickness. However, in the horizontal etching type, bubbles accumulate seriously between the workpiece and the liquid surface, which may cause bubble cavitation and abnormal discharge, leading to damage to the etching surface. The etching current in the vertical etching type is about 1.3 times that of the horizontal etching type, indicating that the bubble mass transfer in the vertical etching type is faster and the etching impedance is smaller, which is beneficial to improve the etching efficiency and obtain a uniform nanoporous structure. Finally, a SiC nanoporous layer with a thickness of 10.6 μm was prepared at etching time t = 50 min in vertical etching type, and the etching efficiency was 212 nm/min. In addition, the prepared nanoporous structure (nanofiber) was connected to the SiC substrate, indicating that it has a good bonding strength.

An improved adaptive position tracking strategy for automatic shift actuator with uncertain parameters

Realizing precise and fast position control of the gear is a challenging issue because of its nonlinearity, parameter uncertainty and external disturbance. Therefore, this paper researches the clutch position control considering the influence because of the factor on the system performance. By virtue of the traditional adaptive control method, an improved strategy based on finite time theory is proposed to further improve the convergence rate as well as the position tracking precision. First, a model of electromechanical clutch actuator system is established by theoretical analysis. Then, an enhanced adaptive controller is designed using finite time idea by introducing power function in the virtual control. And parameter update rate is adopted in the control action. Next, the stability of the control system is proved theoretically. Finally, Matlab simulations and experimental bench test are carried out to exhibit the effectiveness of the presented method. The results show that the satisfactory performance has been achieved with accurate position tracking and fast convergence speed.

Telemetry System to Monitor Elastic Torque on Rolling Stand Spindles

This article outlines the relevance of building online telemetry systems for online monitoring of the technical conditions of rolling mill equipment. Electromechanical systems of the horizontal stand of the plate Mill 5000 are described, when operating in harsh conditions caused by the shock loading when workpieces enter the stand. It is noted that dynamic torque overloads, exceeding the rated motor torque by many-fold, cause the fatigue failure of spindle joints and breakage of rolls. In this regard, the development and implementation of systems for monitoring the elastic torque on spindles are extremely urgent. This issue has long been studied, but the references provide no information on the building principles and hardware composition of such systems. The use of strain gauges connected according to a balanced bridge circuit to measure the elastic torque is justified. This paper’s contribution is the proposed modular principle for building a telemetry monitoring system based on the analysis of known techniques for measuring and transmitting diagnostic data. The developed system structure is provided and the concept of data transfer and processing are explained. This article suggests the inductive power supply of a measuring unit mounted on a shaft without the use of batteries. A hardware structure was developed to be applied in a system for measuring, transmitting, and visualizing signals proportional to the elastic torque, manufactured on the basis of data measuring instruments by leading companies. The specifics of placement and connection of strain gauges are considered. The hardware providing a wireless power supply to the signal encoder and digital data transfer between the transmitter and receiver is described. The results of implementing the system on Mill 5000 are provided. The installation of a telemetry ring and a receiving head for the inductive power supply and data reception is shown. An experimental assessment of the elastic torques occurring when workpieces enter the cage was obtained by implementing a drive control algorithm which provided biting in the drive acceleration mode. The reliability of measuring the elastic torque with an error not exceeding ±5% and the reduction of dynamic loads on the spindle by 1.3–1.5 times due to the elimination of impacts from closing angular gaps in spindle joints was confirmed. This increases the service life of mechanical equipment and reduces the cost of eliminating the accident aftermath. The prospect of modifying the developed system into a cyber-physical system for monitoring the rolling mill’s mechatronic equipment conditions is shown.

SustainableTransformation of Undergraduate Engineering Education in China through Sino-Australian Cooperation: A Case Study on Electro-Mechanical System

China’s undergraduate engineering education is facing two significant challenges: passive learning and limited cross-cultural communication. In response, active learning methods such as project-based learning (PBL) and Sino-foreign cooperative education emerge as promising solutions. However, despite their potential, PBL’s application remains constrained, and many Sino-foreign cooperative programs persist with traditional passive learning approaches. How to adeptly integrate the two, namely realizing active learning in Sino-foreign cooperative education, is the primary objective of this study. To this end, a sustainable strategy for cross-cultural transfer and the adaptation of active learning is proposed. Initially, a PBL-based active learning pedagogy is tailored for a course within a Sino-Australian cooperative undergraduate program. This approach integrates hands-on activities, teamwork, and the flipped classroom method. Moreover, to ensure implementation quality, an assessment method reliant on continuous student survey feedback is suggested. Subsequently, through the statistical analysis of students’ survey data as well as final grades, both quantitative and qualitative results affirm the efficacy of the proposed strategy.

A Dynamic Ultrasound Phantom with Tissue-Mimicking Mechanical and Acoustic Properties.

Tissue-mimicking phantoms are valuable tools that aid in improving the equipment and training available to medical professionals. However, current phantoms possess limited utility due to their inability to precisely simulate multiple physical properties simultaneously, which is crucial for achieving a system understanding of dynamic human tissues. In this work, novel materials design and fabrication processes to produce various tissue-mimicking materials (TMMs) for skin, adipose, muscle, and soft tissue at a human scale are developed. Target properties (Young's modulus, density, speed of sound, and acoustic attenuation) are first definedfor each TMM based on literature. Each TMM recipe is developed, associated mechanical and acoustic properties are characterized, and the TMMs are confirmed to have comparable mechanical and acoustic properties with the corresponding human tissues. Furthermore, a novel sacrificial core to fabricate a hollow, ellipsoid-shaped bladder phantom complete with inlet and outlet tubes, which allow liquids to flow through and expand this phantom, is adopted. This dynamic bladder phantom with realistic mechanical and acoustic properties to human tissues in combination with the developed skin, soft tissue, and subcutaneous adipose tissue TMMs, culminates in a human scale torso tank and electro-mechanical system that can be systematically utilized for characterizing various medical imaging devices.

Development stages of a number of electromechanical systems to establish a green additive remanufacturing ecosystem

Development stages of a number of electromechanical systems to establish a green additive remanufacturing ecosystem

Robust Orientation Estimation from MEMS Magnetic, Angular Rate, and Gravity (MARG) Modules for Human-Computer Interaction.

While the availability of low-cost micro electro-mechanical systems (MEMS) accelerometers, gyroscopes, and magnetometers initially seemed to promise the possibility of using them to easily track the position and orientation of virtually any object that they could be attached to, this promise has not yet been fulfilled. Navigation-grade accelerometers and gyroscopes have long been the basis for tracking ships and aircraft, but the signals from low-cost MEMS accelerometers and gyroscopes are still orders of magnitude poorer in quality (e.g., bias stability). Therefore, the applications of MEMS inertial measurement units (IMUs), containing tri-axial accelerometers and gyroscopes, are currently not as extensive as they were expected to be. Even the addition of MEMS tri-axial magnetometers, to conform magnetic, angular rate, and gravity (MARG) sensor modules, has not fully overcome the challenges involved in using these modules for long-term orientation estimation, which would be of great benefit for the tracking of human-computer hand-held controllers or tracking of Internet-Of-Things (IoT) devices. Here, we present an algorithm, GMVDμK (or simply GMVDK), that aims at taking full advantage of all the signals available from a MARG module to robustly estimate its orientation, while preventing damaging overcorrections, within the context of a human-computer interaction application. Through experimental comparison, we show that GMVDK is more robust to magnetic disturbances than three other MARG orientation estimation algorithms in representative trials.

Improved description of trapped ions as a modular electromechanical system

Improved description of trapped ions as a modular electromechanical system

Impact of alternating precursor supply and gas flow on the LPCVD growth behavior of polycrystalline 3C-SiC thin films on Si

In this paper, we will provide information on the growth mechanism of 3C-SiC using alternating supply deposition (ASD). SiH4 and C3H8 were introduced successively in a low-pressure chemical vapor deposition (LPCVD) system at 1000 °C, forming a stoichiometric polycrystalline 3C-SiC thin film on Si substrates. We demonstrate the influence of different gas flow rates on thin film properties. In detail, altering the flow rates of the precursors and the carrier gas resulted in changes of the growth rate, the surface roughness, the crystal growth mechanisms as well as the crystal quality. Hydrogen inhibition and passivation are proposed to be the main effects influencing the growth behavior of ASD thin films. Applying ASD to grow 3C-SiC thin films with precursors from low to high flow rates resulted in a transition of different growth mechanisms influencing the surface roughness and grain size. Furthermore, we could prove that ASD is a cyclic step-by-step carbon-assisted redistribution of a prior deposited silicon film. This is shown by contact angle measurements of three differently terminated surfaces during the specific phases of one ASD cycle. High resolution transmission electron microscopy (HRTEM) analysis showed a continuous and homogenous thin film and confirmed the absence of silicon- or carbon-rich layers. ASD enables 3C-SiC thin films with customized properties for tailored micro electromechanical system (MEMS) applications.

Mechanical Control of Quantum Transport in Graphene.

2D materials (2DMs) are fundamentally electro-mechanical systems. Their environment unavoidably strains them and modifies their quantum transport properties. For instance, a simple uniaxial strain can completely turn off the conductance of ballistic graphene or switch on/off the superconducting phase of magic-angle bilayer graphene. This article reports measurements of quantum transport in strained graphene transistors which agree quantitatively with models based on mechanically-induced gauge potentials. A scalar potential is mechanically induced in situ to modify graphene's work function by up to 25 meV. Mechanically generated vector potentials suppress the ballistic conductance of graphene by up to 30% and control its quantum interferences. The data are measured with a custom experimental platform able to precisely tune both the mechanics and electrostatics of suspended graphene transistors at low-temperature over a broad range of strain (up to 2.6%). This work opens many opportunities to harness quantitative strain effects in 2DM quantum transport andtechnologies.

Performance evaluation of electro-mechanical railway interlocking system for digital twin application

The industries engaged healthcare, manufacturing, and construction automated with exquisite creativity and innovation at the doorstep of Industry 4.0. In this process, digital twins are diligently used to supplement industrial processes, reduce costs, monitor assets, streamline maintenance, reduce downtime, and enable the creation of connected goods. The research is aimed at finding the digital representation of electro-mechanical railway interlocking elements are simulated and its functionality is verified accordingly. With respect to carry out this research, the Indian Railways Mangalagiri Railway Station blueprints were collected to represent the physical Model which consists of signals, points, a crank handle, an LC gate, and many more elements. In this paper, three interlocking elements such as points, crank handle, and LC gate, are analysed, modelled, and simulated by using Model Sim ME of Libero SoC software. Representation of these digital elements were developed using a smart design canvas. Therefore, the proposed methodology will enhance the safety measures and security levels of the train movements and reduces the time required to replace the faulty relay. Similarly, in future, the proposed model could be dumped into the FPGA kit to verify the real-time data for finding the faulty relay in the relay-based interlocking system.

Discussion and Demonstration of RF-MEMS Attenuators Design Concepts and Modules for Advanced Beamforming in the Beyond-5G and 6G Scenario-Part 1.

This paper describes different variants of broadband and simple attenuator modules for beamforming applications, based on radio frequency micro electro-mechanical systems (RF-MEMS), framed within coplanar waveguide (CPW) structures. The modules proposed in the first part of this work differ in their actuation voltage, topology, and desired attenuation level. Fabricated samples of basic 1-bit attenuation modules, characterized by a moderate footprint of 690 × 1350 µm2 and aiming at attenuation levels of -2, -3, and -5 dB in the 24.25-27.5 GHz range, are presented in their variants featuring both low actuation voltages (5-9 V) as well as higher values (~45 V), the latter ones ensuring larger mechanical restoring force (and robustness against stiction). Beyond the fabrication non-idealities that affected the described samples, the substantial agreement between simulations and measurement outcomes proved that the proposed designs could provide precise attenuation levels up to 40 GHz, ranging up to nearly -3 dB and -5 dB for the series and shunt variants, respectively. Moreover, they could be effective building blocks for future wideband and reconfigurable RF-MEMS attenuators. In fact, in the second part of this work, combinations of the discussed cells and other configurations meant for larger attenuation levels are investigated.

A Comparative Study on Discrepancies in Residential Building Energy Performance Certification in a Mediterranean Context

Energy Performance Certification (EPC) systems are pivotal in addressing the global energy challenge, particularly in the building sector. This study evaluates the efficacy of the EPC offered by the Simplified Building Energy Model interface designed to indicate compliance with the Cypriot building regulations, widely known as iSBEM-Cy Version 3.4a, by examining a typical residential unit in Cyprus. Data on construction features and electromechanical systems were collected, and actual monthly electricity and oil bills were analyzed to determine the total primary energy consumption. Various factors were considered, including energy efficiency and operational parameters for heating, cooling, lighting, auxiliary systems, and domestic hot water. The building energy performance was simulated using iSBEM-Cy, allowing for comparison with real-world energy consumption. Notable discrepancies were observed, particularly in cooling, with deviations reaching 377.4%. Conversely, domestic hot water consumption exhibited minimal variance at 7%, while heating and lighting showed moderate discrepancies (24.3% and −113.9%, respectively). This study underscores the need for rigorous evaluations to shape effective EPC and provides insights into building energy performance in Mediterranean Cyprus. This research contributes to the broader discourse on sustainable construction practices by aligning simulation results with real-world energy consumption.

Two-dimensional van der Waals heterostructure for ultra-sensitive nanoelectromechanical piezoresistive pressure sensing

Micro electromechanical systems (MEMS) micro-pressure sensors have wide applications in consumer electronics, industrial monitoring, and biomedicine. However, as the next-generation portable and wearable devices bloom in recent years, existing design of pressure sensors faces great challenges to break the trade-off between the sensitivity and nonlinearity in the miniaturization process. Here, we report a sandwich-like Graphene/h-BN/Graphene-resistor heterostructure sensing element for micro-pressure detection. This novel design decouples pressure-to-strain translation process and strain-to-electrical signal sensing process by the insulation of bottom graphene structure layer and top graphene piezoresistive layer. We reveal the effects of the heterostructure dimensions, layer number and pretension on the mechanical performance utilizing finite element method (FEM) simulation, and propose the design principle of the piezoresistors and patterning strategy of the heterostructure. Remarkably, the heterostructure exhibits ultra-high sensitivity per unit area, outperforming state-of-art graphene and silicon-based sensors by up to five orders of magnitude, as well as a significant reduction of the nonlinearity. Our work shows tremendous potential of 2D material heterostructure as a promising platform to break the miniaturization limitation of ultrasensitive pressure sensors.

Electromechanical and ferroelectric hysteresis in dense and porous PZT-type piezoceramics

In the present study, particular aspects of the large-signal switching properties and electromechanical hysteresis of the lead zirconate titanate (PZT)-type porous piezoceramics were studied in comparison with the dense piezoceramics of the same composition. Large-signal ferroelectric polarization and strain hysteresis loops were recorded at the bipolar electric fields in the range of 0 ÷ 5 kV/mm and in the frequency range of 0.01 ÷ 5 Hz. Measurements and analysis were performed by means of the electromechanical measurement system (STEPHV) and electromechanical response characterization program (STEP), combining large-signal modeling of the mechanical and electrical behavior of ferroelectric materials.