Large Output Research Articles

A Novel Three-Phase Omnidirectional Wireless Power Transfer System With Zero-Switching-Loss Inverter and Cylindrical Transmitter Coil

Aiming at the problems of large switching loss and large output power fluctuation in the existing omnidirectional wireless power transfer (OWPT) system, a novel OWPT system with zero-switching-loss inverter and cylindrical transmitter coil is proposed. By introducing an auxiliary resonant network with simple structure and low-loss on each phase arm of the three-phase inverter, zero-voltage switching (ZVS) turn-ON and zero-current switching (ZCS) turn-OFF within the full power range can be acquired. The switching loss in the main circuit of inverter is reliably eliminated. The transmitter coil is a cylindrical coil composed of the three curved rectangular coils, whose excitation current amplitude is equal and the phase difference is 120°. It can arise a spatial rotating magnetic field around the transmitter coil and provide an omnidirectional energy transmission channel. The operating principle of soft-switching is analyzed in detail, and the design rules of soft-switching in full power range and the parameter design method of coupler to reduce the fluctuation of output power are given. Ultimately, an experimental prototype is used to verify the feasibility of the proposed OWPT system. The experimental results indicate that the system output power is retained at 93.4W∼104.7W and transfer efficiency is retained at 71.2%∼78.1% under arbitrary angular misalignment of receiver.

Robot joint module based on universal joint configuration driven by SMA wires

Modular robots can adapt to different production needs and working conditions. However, the complexity of structures and the choice of driving modes limit the development of modularization. In this paper, a robot joint module with a universal joint configuration driven by shape memory alloy (SMA) wires is proposed, which has 2-DOFs. For lightweight, the main body of the module is made of polylactic acid materials. SMA wires are used as the actuator due to the advantages of large output displacement, high mass-to-energy ratio, and low activation voltage. Adopting antagonistically arranged SMA wires and bias springs combination method increases the recovery speed and driving angles. A locking device is creatively proposed to avoid the influence of self-biasing spring compression. The detailed kinematic model of the module is established. A proportional integral differential controller is used to precisely control module movements, and the attitude angle sensor is used as the monitoring device. Through the maximum rotation angles and trajectory tracking movement experiments, the module is tested comprehensively, and the results show that the module has good movement characteristics and control precision. In addition, analyzing the tracking performance of the module in the time domain shows that the module has a relatively fast tracking speed. This module is beneficial to the research of configurations, actuators, and controls of modular robots.

A Wideband and Highly Efficient Circulator Load Modulated Power Amplifier Architecture

A complete theoretical analysis is presented for a highly efficient power amplifier (PA) architecture based on a non-reciprocal combiner. The architecture consists of two amplifier branches and a microwave circulator acting as the output combiner, referred to as the circulator load-modulated amplifier (CLMA). The continuous-mode (CM) design technique has been further exploited for the CLMA to demonstrate the wideband capabilities of the architecture. The analysis reveals that the CLMA performs active load modulation to maintain high PA efficiency performance across a wide bandwidth and large output power dynamic range. As a proof of concept, a CLMA demonstrator circuit based on gallium nitride (GaN) transistors and a microwave circulator, is designed and characterized with continuous-wave and modulated-signal measurements. The implemented CLMA prototype circuit experimentally demonstrates Doherty-like efficiency enhancement over a large bandwidth covering 2.1 to 3.5 GHz. In measurements, the prototype exhibits a drain efficiency of 46.7-57.5% at peak output power and 35.6-50.6% at 7-dB output power back-off level, within the design bandwidth. When tested with a 60-MHz multi-carrier orthogonal frequency-division multiplexing (OFDM) signal having a 7-dB peak-to-average power ratio (PAPR), an average efficiency of 48.5% with better than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 47.5-dBc adjacent channel leakage ratio (ACLR) is achieved after applying digital pre-distortion (DPD).

Filling parameters and process optimization of mining–filling synergistic coal-based solid waste paste in Renjiazhuang mine

In this paper, the authors address the issue of large solid waste output and surface subsidence in the western coal base. They focus on the 110904 filling working face of Renjiazhuang Mine and employ a combination of theoretical analysis, numerical simulation, and field practice to analyze the limit caving step and cycle pressure step of the working face. The authors propose a mining-filling coordination scheme called “three mining and one charging”. Through numerical simulation, they demonstrate that this scheme ensures the time-space continuity of the mining-filling cycle and is theoretically feasible. Additionally, the authors conduct nine groups of orthogonal simulation tests to identify the main factors affecting the filling effect. They conclude that the filling rate is the primary controlling factor, and there is a positive correlation between the filling rate and 1-day strength. The authors implement hanging pipe filling in the return air roadway of the 110904 working face, achieving a filling material 1-day strength of 2 MPa and a filling ratio of 80%. The mining-filling synergy scheme proves effective and feasible. However, the issue of pipe plugging during the filling process requires further optimization of the particle gradation in the subsequent filling material ratio scheme. Overall, the proposed mining-filling collaborative process serves as a theoretical reference for similar filling faces.

Optimized Automated Analysis of Live Neuronal Mitochondria Homeostasis Modulation by Isoform-Specific Retinoic Acid Receptors.

The complex mitochondrial network makes it very challenging to segment, follow, and analyze live cells. MATLAB tools allow the analysis of mitochondria in timelapse files, considerably simplifying and speeding up the process of image processing. Nonetheless, existing tools produce a large output volume, requiring individual manual attention, and basic experimental setups have an output of thousands of files, each requiring extensive and time-consuming handling. To address these issues, a routine optimization was developed, in both MATLAB code and live-script forms, allowing for swift file analysis and significantly reducing document reading and data processing. With a speed of 100 files/min, the optimization allows an overall rapid analysis. The optimization achieves the results output by averaging frame-specific data for individual mitochondria throughout time frames, analyzing data in a defined manner, consistent with those output from existing tools. Live confocal imaging was performed using the dye tetramethylrhodamine methyl ester, and the routine optimization was validated by treating neuronal cells with retinoic acid receptor (RAR) agonists, whose effects on neuronal mitochondria are established in the literature. The results were consistent with the literature and allowed further characterization of mitochondrial network behavior in response to isoform-specific RAR modulation. This new methodology allowed rapid and validated characterization of whole-neuron mitochondria network, but it also allows for differentiation between axon and cell body mitochondria, an essential feature to apply in the neuroscience field. Moreover, this protocol can be applied to experiments using fast-acting treatments, allowing the imaging of the same cells before and after treatments, transcending the field of neuroscience.

A Self-Triggered Digitally Assisted Hybrid LDO with 110 ns Settling Time in 65 nm CMOS

This article presents a self-triggered digitally assisted hybrid low-dropout regulator (LDO). The proposed architecture uses an analog LDO for steady-state operation and a digital LDO to track large output current changes. The dual loop has a loop controller for coherent operation, and the digital loop is only triggered when there is a large load step. Therefore, the proposed LDO inherits some of the advantages of both parts. It achieves a high power supply rejection ratio (PSRR) from the analog part. The digital loop has a faster settling time and consumes less static power than the analog loop. In this design, the maximum load is 200 mA. For heavy load conditions, PSRR is −40 dB at 1 MHz. The quiescent current is 200 μA. The undershoot/overshoot with the corresponding settling time measured under a load current step of 200 mA/10 ns are 82 mV/89 ns and 112 mV/110 ns, respectively. The proposed LDO achieves a competitive 4.48 ps figure of merit. In the TSMC 65 nm process, the active area is approximately 0.027 mm2.

Enhanced cycle loading stability of shock transmission units via adjusting boron content of polyborosiloxanes

Polyborosiloxanes (PBSs)-based shock transmission units (STUs) play a vital role in the seismic resistance of the bridge due to the large output damping force and simple structure without the use of a valve structure. However, Dow Corning 3179 (DC3179)-based STU had poor locking performance under cyclic loads and filling processability due to excessive viscosity, which was unfavorable for engineering applications. In order to achieve the locking of the PBS-based STUs with low complex viscosities of PBSs under cyclic loading, three PBSs with different boron content were synthesized via the reaction of hydroxyl-terminated polydimethylsiloxane (PDMS-OH) and boric acid (H3BO3). The results showed that the variation of the silicon-boron ratios would affect the complex viscosity, storage modulus, and loss modulus. The essence is that the formation of a non-bonding crosslink between boron atoms with vacancies and oxygen atoms with lone electron pairs in adjacent chains affects the movement of molecular chains. PBSs with low complex viscosity and high storage modulus were prepared by adjusting the silicon-boron ratios, which could enhance the cyclic loading stability of PBS-based STUs.

An evaluation on large language model outputs: Discourse and memorization

We present an empirical evaluation of various outputs generated by nine of the most widely-available large language models (LLMs). Our analysis is done with off-the-shelf, readily-available tools. We find a correlation between percentage of memorized text, percentage of unique text, and overall output quality, when measured with respect to output pathologies such as counterfactual and logically-flawed statements, and general failures like not staying on topic. Overall, 80.0% of the outputs evaluated contained memorized data, but outputs containing the most memorized content were also more likely to be considered of high quality. We discuss and evaluate mitigation strategies, showing that, in the models evaluated, the rate of memorized text being output is reduced.

Spin‐Orbit Readout Using Thin Films of Topological Insulator Sb2Te3 Deposited by Industrial Magnetron Sputtering

AbstractDriving a spin‐logic circuit requires the production of a large output signal by spin‐charge interconversion in spin‐orbit readout devices. This should be possible by using topological insulators, which are known for their high spin‐charge interconversion efficiency. However, high‐quality topological insulators have so far only been obtained on a small scale, or with large scale deposition techniques that are not compatible with conventional industrial deposition processes. The nanopatterning and electrical spin injection into these materials have also proven difficult due to their fragile structure and low spin conductance. The fabrication of a spin‐orbit readout device from the topological insulator Sb2Te3 deposited by large‐scale industrial magnetron sputtering on SiO2 is presented. Despite a modification of the Sb2Te3 layer structural properties during the device nanofabrication, a sizeable output voltage is measured that can be unambiguously ascribed to a spin‐charge interconversion process. The results pave the way for the integration of layered van der Waals materials in spin‐logic devices.

Harvesting vibration energy by novel piezoelectric structure with arc-shaped branches

In this study, we proposed a novel energy harvester that consists of a piezoelectric inverted beam and two arc-shaped branches. The harvester owns the characteristics of super-harmonic and sub-harmonic vibrations, so its working frequency bandwidth can be significantly extended. Then, for broadband excitation, the harvester can keep a fairly large electric output. The theoretical model is established at first, and the simulations for frequency-sweeping and harmonic excitations are carried out. The results show that there exist the super-harmonic and sub-harmonic vibrations in response. Then, the validation experiments are conducted, and the results prove the theoretical analyses. Furthermore, in the experiments there occurs the transition from the synchronization vibration to sub-harmonic resonance, which results in a dramatic increase in amplitude and output. Finally, the experiment for stochastic excitation is carried out. The results show the harvester could give a large electric output under weak stochastic excitations. For the excitation of PSD = 0.07 g2/Hz, the output power can reach 21.2 μW.

Design and test a pneumatically actuated microgripper based on structural stiffness.

In response to the problem that the actual amplification ratio of the compliant motion amplification mechanism cannot be further improved, this paper introduces a two-stage amplification microgripper based on structural stiffness that is driven by pneumatics. The mechanism not only has the advantages of good symmetry, compact structure, and large output displacement but can also reduce the relative error of the theoretical and experimental amplification ratios. The first-stage mechanism selects high-stiffness mechanisms and high-stiffness flexure hinges, and the second-stage mechanism uses low-stiffness mechanisms and low-stiffness flexure hinges. The arrangement order of the mechanism is determined by the working mode analysis. The specific dimensions of the mechanism and flexure hinges are determined through structural size optimization so that the amplification performance of the mechanism will be optimal. The experimental results show that the displacement amplification ratio of both the opening and closing of the microgripper is 41.8.

Design and Experiments of Electro-Hydrostatic Actuator for Wheel-Legged Robot with Fast Force Control Response

The wheel-legged robot combines the functions of wheeled vehicles and legged robots: high speed and high passability. However, the limited performance of existing joint actuators has always been the bottleneck in the actual applications of large wheel-legged robots. This paper proposed a highly integrated electro-hydrostatic actuator (EHA) to enable high-dynamic performance in giant wheel-legged robots (&gt;200 kg). A prototype with a high force-to-weight ratio was developed by integrating a micropump, a miniature spring accumulator, and a micro-symmetrical cylinder. The prototype achieves a large output force of more than 9400 N and a high force-to-weight ratio of more than 2518 N/kg. Compared with existing EHA-based robots, it has a higher force-to-weight ratio and can bear larger loads. A detailed EHA model was presented, and controllers were designed based on sliding mode control and PID methods to control the output position and force of the piston. The model’s accuracy is improved by identifying uncertain parameters such as friction and leakage coefficient. Finally, both simulations and experiments were carried out. The results verified the fast response of force control (step response within 50 ms, the force tracking control frequency about 6.7 Hz) and the developed EHA’s good potential for future large wheel-legged robots.

A force-compensated compliant MEMS-amplifier with electrostatic anti-springs

In this paper, an electrostatic compliant mechanical amplifier intended for force-compensated displacement amplification in MEMS sensor applications is described. Usually, mechanical transformers that enhance a small input displacement into a large output displacement generate large forces at the input of the transformer. The microsystem proposed here allows for the reduction and compensation of the input stiffness of the amplifier and any mechanical components connected to it while providing a constant amplification ratio at the same time. The amplifying mechanism features bidirectional electrostatic anti-springs enabling the control of the stiffness by applying a constant DC voltage. The electrode design of the anti-springs and its influence on the force-displacement characteristic, the side instability and the maximal displacement are studied through analytical approaches and supported by FEA and by experiments. Based on the derived models, a compliant electromechanical amplifier is developed, featuring an amplification ratio of 50. For this amplifier the initial input stiffness of 422 N/m could be reduced to 6.8 N/m by applying a voltage of 100 V. As an additional application, we show how the amplifier can be used as a mechanical force sensor with tuneable sensitivity, where the forces at the input are transformed into large output displacements. Through experiments, we show how the sensitivity can be adjusted and increased by a factor of 25 by applying a voltage at the anti-springs.

A Current-Mode Optoelectronic Receiver IC for Short-Range LiDAR Sensors in 180 nm CMOS

This paper presents three different types of on-chip avalanche photodiodes (APDs) realized in a TSMC 180 nm 1P6M RF CMOS process, i.e., a P+/N-well (NW) APD for its high responsivity and large bandwidth by excluding slow diffusion currents; a P+/Deep N-well (DNW) APD for its improved near-infrared (NIR) sensitivity; and a P+/NW/DNW APD for its capability to prevent premature edge breakdown and improve NIR sensitivity. Thereafter, a conventional voltage-mode optoelectronic receiver (V-OER) was realized to confirm the feasibility of the three on-chip APDs. However, the measured results of the V-OER demonstrate a very narrow dynamic range. Therefore, we propose a current-mode optoelectronic receiver (C-OER) realized in the same CMOS process for the applications of short-range LiDAR sensors, where current-conveyor input buffers are exploited to deliver the photocurrents with no significant signal loss to the following inverter cascode transimpedance amplifier, hence resulting in an extended dynamic range. The optically measured results of the C-OER with an 850 nm laser source demonstrate large output pulses. The C-OER chip consumes 47.8 mW from a 1.8 V supply and the core occupies 0.087 mm2.

Emission characteristics of coal gasification fine slag direct combustion and co-firing with coal

Coal gasification is an effective way to use coal cleanly and efficiently, and coal gasification fine slag is a by-product of coal gasification with high carbon content, large specific surface area, developed pore structure and large output during production. At present, combustion has become an effective way to dispose of coal gasification fine slag on a large scale, and the coal gasification fine slag after combustion treatment can be further used for construction raw materials. In this paper, the emission characteristics of gas-phase pollutants and particulate matter under different combustion temperatures (900 °C, 1100 °C, 1300 °C) and combustion atmosphere (5%, 10%, 21% O2 concentration) are studied with the drop tube furnace experimental system. By co-firing different proportions of coal gasification fine slag (10%, 20%, 30%) and raw coal, the pollutants formation law under co-firing conditions is studied. Scanning electron microscopy-energy spectroscopy (SEM-EDS) is used to characterize the apparent morphology and elemental composition of particulate samples. The measurement results of gas-phase pollutants show that the increase of furnace temperature and O2 concentration can effectively promote combustion and improve burnout characteristics, but the emission of gas-phase pollutants increases. A certain proportion (10%–30%) of coal gasification fine slag is added to the raw coal, which reduces the total emission of gas-phase pollutants (NOx and SOx). Studies on the characteristics of particulate matter formation show that co-firing with coal gasification fine slag in raw coal can effectively reduce submicron particle emission, and the lower fine particle emission is also detected at lower furnace temperature and oxygen concentration. The element analysis of particulate matter formation shows that the Fe, Si and S elements content of submicron particle generated by YL (the coal gasification fine slag generated by water slurry furnace in of Shaanxi Extended China Coal Yulin Energy Chemical Co., Ltd) sample increases significantly with the increase of furnace temperature and O2 concentration, which is the main influencing factor for the increase of submicron particle. With the increase of the mixing ratio of YL sample, the content of major elements such as Fe, K and Mg of submicron particle decreases significantly, which is an important reason why the amount of the submicron particle decreases.

Evolution from Telescoping to Bending: An Origami-Inspired Flexible Bending Actuator

Soft actuators have great potential in human–machine interaction and soft robotics innovation. Origami exhibiting outstanding structural and topological properties can be a paradigm for people to design various soft robots. Inspired by origami, we have previously designed a telescopic actuator with excellent performance, mainly large force output, and two-way working. Although significant advances have been made in soft bending actuators, their further study and applications are limited due to small force output in a monotonous work style. In this paper, we design a series of novel bending actuators that inherit our prior telescopic actuator’s excellent characteristics to diversify soft actuators’ motion forms. Several actuators of different sizes are fabricated using three different materials and evaluated on a designed test platform. The test results show that actuators of different sizes using different materials perform differently. Namely, the maximum tip force produced by an actuator reaches 9.6 N, and the maximum bending angle is achieved by another one up to 138°. Finally, extensive demonstrations and tests include wriggling, gripping, and bidirectional motion in the water. They show our flexible bending actuators’ distinguishing characteristics of large output force and two-way working.

Multi-field coupled dynamics for a movable tooth drive system integrated with shape memory alloys

The harmonic movable tooth drive system integrated with shape memory alloys has a small size and a large output torque. Its dynamics performance is the key factor for evaluating the drive system. Here, for the drive system, based on its structure and working principle, the coupled dynamics equations are deduced. Using the equations, changes of the natural frequencies of the drive system during the operation are investigated. Effects of the system parameters and SMA wires phase change process on the natural frequencies are analyzed. The nonlinear resonant frequencies of the drive system and its amplitude-frequency relationship are studied. Results show that natural frequencies of the drive system change periodically which is caused by SMA phase transformation during operation. The eccentricity, movable tooth radius, the wave generator radius and SMA wire length have also important effects on the natural frequencies of the drive system. The nonlinear resonant frequencies are smaller than linear resonant frequencies. In the design of the drive system, the coupled nonlinear effects of the temperature, phase change, stress and strain of the SMA wires, and the system parameters of the movable tooth drive system should be considered. In this paper, the coupled nonlinear dynamics model of the harmonic movable tooth drive system integrated with shape memory alloys is proposed in which the coupled effects of the temperature, phase change, stress and strain of the SMA, and the system parameters of the movable tooth drive system are considered.

Voltage Drop Estimation during Shore Connection with the Use of Motor Drives Modified as Static Frequency Converters

Ship-to-shore connection is an important technological element that reduces air pollution in ports. Therefore, ports install facilities that allow mooring ships to connect to the port distribution network. By 2025, this will be mandatory for all ports in Europe. This can be a challenging task in most ports due to the different frequency of the network and ship frequency. This problem can be solved by the use of grid-forming static frequency converters. This solution also brings some other advantages: The ship is not threatened by high shore short-circuit currents, and the port distribution network is not affected by the character of the ship load. However, frequency converter software must include a droop control algorithm to ensure that voltage deviations do not exceed the allowed limits during transients. Typical frequency converters used for shore connection are those developed as static frequency converters (SFCs). However, those converters were not developed for large power outputs, which are needed to power large vessels, such as ferries or cruise ships. This paper proposes motor drives that were modified to operate as SFCs. This approach has quite a lot of advantages which are described in this article. This paper describes both a standard shore connection system without a frequency converter and a solution that includes static frequency converters. The paper then focusses on voltage deviation estimations during connection/disconnection of large load (ferry or cruise ship) to static frequency converters. In this work, a high-voltage shore connection (HVSC) simulation model is developed, including a frequency converter, a shoreside transformer, medium-voltage (MV) connection cables, and a power system of the ship, to analyze in detail the behavior of the system in the case of connection or disconnection of the ship load. The model was made in DIgSILENT PowerFactory for the case of a commercial port in southern France. The model gives credible estimations of voltage drops/surges during transient and steady states.

A Single-Cycle Forward-Flybaсk Stabilized DC-DC Voltage Converter Part. 2. Power Stage Control Device

The article addresses the development of a single-cycle single-transistor forward-flyback DC voltage converter. The article’s second part shows the features of constructing a secondary power supply source based on a single-cycle single-transistor forward-flyback power converter stage considered in the article’s first part [1]. The power supply is constructed as a closed-loop automatic control system responding to mismatch of the output voltage from its setpoint value based on the principle of subordinate current control. The PWM controller initial starting scheme with its subsequent auxiliary feeding from the power transformer additional windings is proposed. The results of studying the scheme carried out using computer simulation in the OrCAD software are presented. The proposed scheme allows the device to remain operational even with a relatively poor coupling coefficient between the transformer’s power and auxiliary feed windings. In the OrCAD software, a simulation computer model was developed for a secondary power supply source based on the new structure of a single-cycle single-transistor forward-flyback power converter stage with the proposed method for starting the PWM controller. Based on the results obtained from studying the processes running in the secondary power supply source, time diagrams confirming the circuit operability are presented. The simulation has shown that a sufficiently large output power can be obtained on a single-cycle single-transistor forward-flyback power converter stage.

Self‐powered wireless body area network for multi‐joint movements monitoring based on contact‐separation direct current triboelectric nanogenerators

AbstractBody area network has attracted extensive attention for its applications in athletics, medical, diagnosis, and rehabilitation training in the next generation personalized health care solutions. Here, a contact‐separation direct current triboelectric nanogenerators (CSDC‐TENGs) based self‐powered wireless body area network (SWBAN) is reported that enables multi‐joint movements monitoring for human motion. The CSDC‐TENG is designed as a flexible active sensor with an internal contact switch, and the flexible substrate makes the TENG‐sensor stick onto skin easily. Due to the internal switch, the CSDC‐TENG could generate a DC current, a large instantaneous output voltage exceeds 700 V, and an instantaneous power can reach 1.076 W, which is more than 23 000 times higher than that of the traditional contact‐separation mode TENG in same size and materials without the switch. By coupling with flexible coil, the fixed high‐frequency radio signals can be modulated and emitted clearly ranging from 6 to 16 MHz, which can be wirelessly received and demodulated through a reader. Moreover, the SWBAN is demonstrated in a real time monitoring system for joints motion. This work has realized the wearable TENG for self‐powered wireless real‐time monitoring of body movements driven by low‐frequency human daily activities, which may promote a tremendous development of intelligent healthcare, wireless sensing system and body area network.image