Transfer Torque Research Articles

Study on the safety performance of large offshore wind turbine coupling

An offshore wind turbine coupling (OWTC) safety performance assessment method for torque transfer and overload protection of the main drive train of offshore wind turbine is proposed in the paper. First, the local mechanical model and the overall finite element model of the OWTC are established, and the fatigue life assessment method of the OWTC is given. Then, the effectiveness of the proposed method was verified by experiments and finite elements. The structural strength under different working conditions of the OWTC and the influence of the bolt tightening torque on the OWTC slip torque are studied, and the torque transfer efficiency is evaluated. Finally, the stress response of the OWTC was obtained by the finite element method considering the time-series torque load, the fatigue life of the OWTC was evaluated by combining the S/N curve parameters and the Palmgren-Miner rule. The results show that the proposed method for assessing the safety performance of the OWTC is reliable and valid. The calculated results of the local mechanical model are in good agreement with the test and simulation results, and the connecting rods and bolts of the OWTC are highly susceptible to damage under fatigue loading and should be of particular concern.

Physics teaching via dialogic discussions about circus activities

Circus art excites amazes and delights. Most of circus genres are based on the principles of classical physics. Dialogic discussions are known as an instrument to identify conceptual barriers (misconceptions) and facilitate their further revision. The present study integrates the three worlds: physics education, dialogic teaching and circus art; and provides a research foundation for experiential physics teaching through dialogic discussions about circus tricks (DDCT) in formal and informal setups. It aims at examining the potential of DDCT as a tool for identifying misconceptions and facilitating conceptual change regarding physics concepts. The study encircles about 40 DDCT provided in the Israeli KESHET circus. In total, about 5,500 people watched the shows. From them, about 400 actively participated in the DDCT. We analyze in details four typical DDCT relating (a) circular motion, (b) moment of inertia, (c) torque, and (d) heat transfer. For each DDCT we demonstrate the way it pinpoints participants’ knowledge and its implementation in circus devices’ analysis. Further we examine whether and how the DDCT could facilitate developing physics knowledge and/or going through a meaningful conceptual change regarding each of these concepts. Due to our results DDCT seems to be an original and promising approach to bring advanced physics ideas to the general public, in ways that are interesting, experiential and relatively easy to understand. We finish with practical recommendations for physics educators (as well as circus artists) who would like to implement DDCT in their classes (shows).

Rotate Vector Reducer Fault Diagnosis Model Based on EEMD-MPA-KELM

With the increase of service time, the rotation period of rotating machinery may become irregular, and the Ensemble Empirical Mode Decomposition (EEMD)can effectively reflect its periodic state. In order to accurately evaluate the working state of the Rotate Vector (RV) reducer, the torque transfer formula of the RV reducer is first derived to theoretically prove periodicity of torque transfer in normal operation. Then, EEMD is able to effectively reflect the characteristics of data periodicity. A fault diagnosis model based on EEMD-MPA-KELM was proposed, and a bearing experimental dataset from Xi‘an Jiaotong University was used to verify the performance of the model. In view of the characteristics of the industrial robot RV reducer fault was not obvious and the sample data is few, spectrum diagram was used to diagnose the fault from the RV reducer measured data. The EEMD decomposition was performed on the data measured by the RV reducer test platform to obtain several Intrinsic Mode Functions (IMF). After the overall average checking and optimization of each IMF, several groups of eigenvalues were obtained. The eigenvalues were input into the Kernel Extreme Learning Machine (KELM) optimized by the Marine Predators Algorithm (MPA), and the fault diagnosis model was established. Finally, compared with other models, the prediction results showed that the proposed model can judge the working state of RV reducer more effectively.

Practical active traction control for independent‐wheel‐drive electric vehicle based on slip‐ratio threshold determination

AbstractThe traditional traction control system (TCS) based on hydraulic braking only works when the wheels are slipping, which will cause the problem of slow response to extreme slip. In addition, the TCS of four‐wheel‐independent‐drive electric vehicle (4WIDEV) is often based on road adhesion characteristics identification or optimal slip ratio identification to implement active control, which is difficult to achieve in engineering. Aiming at this problem, a practical active TCS is proposed in this paper. Firstly, according to the wheel slip state of the front and rear axles, the dynamic transfer of torque between axles is realized to maintain the vehicle propulsion power. Second, the adhesion conditions between road and tire are classified, and two sets of target slip ratio thresholds are formulated for high and low adhesion pavement, respectively. Then the current road adhesion coefficient is estimated by using the advantage that the in‐wheel motor torque can be obtained in real‐time. Thirdly, the overall framework of the control strategy is established, the logic threshold control algorithm is adopted for tracking the wheel target slip ratio. Finally, the simulation results show that the proposed active TCS can improve the vehicle power and avoid excessive wheel slipping.

Nonlinear multi-physical system identification of a chemical stirred tank

This paper presents a coupled electro-thermo-mechanical lumped parameter model for a chemical stirred tank, considering the device-related thermo-mechanical losses and process-related effects. This separation can help compute the key performance factors for competing processes during the scale-up. As the model has unknown thermo-mechanical parameters, two system identification experiment sets are conducted to determine the friction torque and heat transfer coefficient. A data acquisition system is developed in this study based on the Teensy 4.1 microcontroller to stream the logged data of the installed sensors on the serial port. An extended Kalman filter and a moving horizon estimation exploit the model and measurements to estimate the unknown model parameters. The results include the coupled electro-thermo-mechanical effects in estimating the heat transfer coefficient.

Modulations in motor unit discharge are related to changes in fascicle length during isometric contractions.

The integration of electromyography (EMG) and ultrasound imaging has provided important information about the mechanisms of muscle activation and contraction. Unfortunately, conventional bipolar EMG does not allow an accurate assessment of the interplay between the neural drive received by muscles, changes in fascicle length and torque. We aimed to assess the relationship between modulations in tibialis anterior muscle (TA) motor unit (MU) discharge, fascicle length, and dorsiflexion torque using ultrasound-transparent high-density EMG electrodes. EMG and ultrasound images were recorded simultaneously from TA using a 32-electrode silicon matrix while performing isometric dorsiflexion contractions at two ankle joint positions (0° or 30° plantar flexion) and torques (20% or 40% of maximum). EMG signals were decomposed into MUs and changes in fascicle length were assessed with a fascicle-tracking algorithm. MU firings were converted into a cumulative spike train (CST) that was cross-correlated with torque (CST-torque) and fascicle length (CST-length). High cross-correlations were found for CST-length (0.60, range: 0.31-0.85) and CST-torque (0.71, range: 0.31-0.88). Cross-correlation delays revealed that the delay between CST-fascicle length (∼75 ms) was smaller than CST-torque (∼150 ms, P < 0.001). These delays affected MU recruitment and de-recruitment thresholds since the fascicle length at which MUs were recruited and de-recruited was similar but MU recruitment-de-recruitment torque varied. This study demonstrates that changes in TA fascicle length are related to modulations in MU firing and dorsiflexion torque. These relationships allow assessment of the interplay between neural drive, muscle contraction and torque, enabling the time required to convert neural activity into movement to be quantified.NEW & NOTEWORTHY By employing ultrasound-transparent high-density EMG electrodes, we show that modulations in tibialis anterior muscle motor unit discharge rate were related to both changes in fascicle length and resultant torque. These relationships permitted the quantification of the relative delays between fluctuations in neural drive, muscle contraction, and transfer of torque via the tendon during sustained isometric dorsiflexion contractions, providing information on the conversion of neural activity into muscle force during a contraction.

The Simulation of a Pid Controlled Robotic Drive Based on Bond Graph Modelling

AbstractDuring the study, the simulation of a robotic drive was realised using the 20-sim simulation software. The assumed robotic drive consists of an ideal permanent magnetic DC motor, a gear pair to realise the speed reduction, a torque transfer torsion shaft and a differential gear pair to change the direction and inertia. The drive is controlled by a speed control loop using a PID controller. In line with the purpose and result of the study, the simulation proved the effectiveness of Bond Graph-based modelling.

Hydrodynamical evolution of black-hole binaries embedded in AGN discs

ABSTRACT Stellar-mass binary black holes (BBHs) embedded in active galactic nucleus (AGN) discs are possible progenitors of black hole mergers detected in gravitational waves by LIGO/VIRGO. To better understand the hydrodynamical evolution of BBHs interacting with the disc gas, we perform a suite of high-resolution 2D simulations of binaries in local disc (shearing-box) models, considering various binary mass ratios, eccentricities and background disc properties. We use the γ-law equation of state and adopt a robust post-processing treatment to evaluate the mass accretion rate, torque and energy transfer rate on the binary to determine its long-term orbital evolution. We find that circular comparable-mass binaries contract, with an orbital decay rate of a few times the mass doubling rate. Eccentric binaries always experience eccentricity damping. Prograde binaries with higher eccentricities or smaller mass ratios generally have slower orbital decay rates, with some extreme cases exhibiting orbital expansion. The averaged binary mass accretion rate depends on the physical size of the accretor. The accretion flows are highly variable, and the dominant variability frequency is the apparent binary orbital frequency (in the rotating frame around the central massive BH) for circular binaries but gradually shifts to the radial epicyclic frequency as the binary eccentricity increases. Our findings demonstrate that the dynamics of BBHs embedded in AGN discs is quite different from that of isolated binaries in their own circumbinary discs. Furthermore, our results suggest that the hardening time-scales of the binaries are much shorter than their migration time-scales in the disc, for all reasonable binary and disc parameters.

Simulation on spin wave transmission and domain wall dynamics in a permalloy nanostrip

Spin waves (SWs), the magnons, can potentially be used for fast and energy efficient information processing and the interaction of SWs with a magnetic domain wall (DW), which is quite complex, can play a key role in the development of magnonic devices. Manipulation of SW amplitude and phase is the key step in realization of spin wave devices. The SW transmission through DW is strongly dependent on the magnetization angle inside the DW and spatial movement of DW is coupled to this interaction. Magnonic spin transfer torque and linear momentum transfer of SW, collectively, control the motion of the DW and the rotation of magnetization inside the DW. In the present work, micromagnetic simulations were performed considering a ferromagnetic permalloy nanostrip with perpendicular magnetic anisotropy (PMA) using mumax3 platform to study SW transmission through DW. The correlation between rotation in magnetization tilt angle (δϕ) inside an initially Néel-type DW and SW-transmission ratio (TD) was investigated at different SW-frequencies ranging from 18 GHz to 28 GHz. Applied SW amplitude at each frequency was sufficiently large for transverse DW to show oscillatory motion along the length of the strip. The results showed that the dependence of TD on rotation in magnetization angle (δϕ) decreases as the frequency of SW is increased and it approaches a nearly isotropic behavior at higher frequencies.

Optimization of Seating Position and Stimulation Pattern in Functional Electrical Stimulation Cycling: Simulation Study.

Two significant challenges facing functional electrical stimulation (FES) cycling are the low power output and early onset of muscle fatigue, mainly due to the non-physiological and superficial recruitment of motor units and weakness of the antagonistic muscles. Thus optimization of the cycling biomechanical properties and stimulation pattern to achieve maximum output power with minimum applied electrical stimulus is of great importance. To find the optimal seating position and stimulation pattern, the previous works either ignored the muscle's force-velocity and force-length properties or employed complicated muscle models which was a massive barrier to clinical experiments. In this work, an easy-to-use and precise muscle model in conjunction with Jacobian-based torque transfer functions were adopted to determine the optimal seating position, trunk angle, crank arm length, and stimulation intervals. Furthermore, the impact of muscle force-velocity factor in finding the optimal seating position and stimulation intervals was investigated. The simulation models showed the trivial effect of the force-velocity factor on the resulting optimal seating position of six healthy simulated subjects. This method can enhance the FES-cycling performance and shorten the time-consuming process of muscle model identification for optimization purposes.

Analysis on Flow and Temperature Field of High-Power Magnetorheological Fluid Transmission Device

Aiming to solve the problem of high-power magnetorheological fluid transmission heat dissipation, a new type of magnetorheological fluid drive disk is designed. The characteristics of the flow field and temperature field of high power MR fluid transmission devices are analyzed. Meanwhile, the influence of factors, such as rotating speed, inlet velocity, inlet position, diameter and number of magnetic columns, on the flow field are also investigated. Furthermore, the distribution characteristics of the ultimate slip power and the transient temperature field are obtained. The experimental platform of an MR fluid transmission device was established, and the torque transfer performance and heat dissipation performance were tested. The experimental results show that the device has good heat dissipation performance and can transfer high-power torque.

Bit-error-rate aware sensing-error correction interaction in spintronic MRAM

Internal memories e.g., DRAM and SRAM are partially being replaced by non-volatile memories (NVMs) for the challenges caused by storage capacitance and leakage current at nanoscale feature sizes. Spin–torque transfer magnetoresistive random access memory (STT-MRAM) is a proper non-volatile memory candidate for next-generation main memory on account of low write energy, high speed and high endurance relatively. However, due to imperfect magnetic tunnel junction (MTJ) and array-level density requirement, the failure probability of STT-MRAM becomes a critical issue. The sensing operation suffers from input offset of sensing amplifier (SA), reference distribution and read-disturbance. In order to alleviate the error rate, error-correcting code (ECC) is commonly implemented as a separate module with redundant bit, additional energy consumption and layout overhead. In this paper, we propose a novel cross detected SA-ECC interact design methodology using ECC Galois field compression (GFC), so that the amount of data processing in ECC-GFC is highly depended on the output of SA. Simulation is performed with a 28 nm CMOS process and a 40 nm MTJ compact model. Experimental results show that when SA is with high bit-error-rate (BER), ECC layout area is increased by 1% with GFC. When SA is with low BER, layout area can be reduced by 10%. Under the condition of high and low BER of SA, the maximum power consumption decreases by 10% and 17% respectively compared with the conventional ECC module.

Magnetisation switching dynamics induced by combination of spin transfer torque and spin orbit torque

We present a theoretical investigation of the magnetisation reversal process in CoFeB-based magnetic tunnel junctions (MTJs). We perform atomistic spin simulations of magnetisation dynamics induced by combination of spin orbit torque (SOT) and spin transfer torque (STT). Within the model the effect of SOT is introduced as a Slonczewski formalism, whereas the effect of STT is included via a spin accumulation model. We investigate a system of CoFeB/MgO/CoFeB coupled with a heavy metal layer where the charge current is injected into the plane of the heavy metal meanwhile the other charge current flows perpendicular into the MTJ structure. Our results reveal that SOT can assist the precessional switching induced by spin polarised current within a certain range of injected current densities yielding an efficient and fast reversal on the sub-nanosecond timescale. The combination of STT and SOT gives a promising pathway to improve high performance CoFeB-based devices with high speed and low power consumption.

Developing Spiral-Conical Gears for Microsystems by Wire-Assisted Electrical Discharge Machining

The requirements of gears are increasing rapidly in the global market for applications from micro electro mechanical systems (MEMS) to aerospace. Gears of various profiles and types including spiral-conical are used for motion as well as torque transfer in microsystems. The development of such gears is a challenging task because no compromise in their quality is acceptable. It necessitates highly accurate gear manufacturing process. This article presents such a process i.e. wire-assisted electrical discharge machining (WEDM) and development of stainless-steel made spiral-conical gears of miniature size. All minute aspects of spiral-conical gear development by WEDM are reported in this paper. In order to investigate the impact of process parameters and gear quality, an experimental study has been conducted based on Taguchi’s robust design of experiment technique. The developed gears are found with good manufacturing quality characteristics.

Torque Transfer to a Conducting Particle Using the Lorentz Force

Torque Transfer to a Conducting Particle Using the Lorentz Force

Magnetism, symmetry and spin transport in van der Waals layered systems

The discovery of an ever-increasing family of atomic layered magnetic materials, together with the already established vast catalogue of strong spin–orbit coupling and topological systems, calls for some guiding principles to tailor and optimize novel spin transport and optical properties at their interfaces. Here, we focus on the latest developments in both fields that have brought them closer together and make them ripe for future fruitful synergy. After outlining fundamentals on van der Waals magnetism and spin–orbit coupling effects, we discuss how their coexistence, manipulation and competition could ultimately establish new ways to engineer robust spin textures and drive the generation and dynamics of spin current and magnetization switching in 2D-materials-based van der Waals heterostructures. Grounding our analysis on existing experimental results and theoretical considerations, we draw a prospective analysis about how intertwined magnetism and spin–orbit torque phenomena combine at interfaces with well-defined symmetries and how this dictates the nature and figures of merit of spin–orbit torque and angular momentum transfer. This will serve as a guiding role in designing future non-volatile memory devices that utilize the unique properties of 2D materials with the spin degree of freedom.

Shifting Process Optimization of Dedicated Hybrid Transmission

The shifting process of a hybrid electric vehicle (HEV) could be implemented by a motor to simplify the control requirement when the clutch is engaged. In order to reduce the vehicle jerk and simplify the clutch control requirement during the shifting process, this paper introduces a 3-speed dedicated hybrid transmission (3DHT) with P1/P3 configuration and a power shift control strategy. A finite-time linear quadratic regulator (LQR) is proposed to smoothly transfer torque and suppress driveline oscillations during the torque transfer process with a maximum jerk of 5.6 m/s³. Since the clutch stays engaged, a predictive sliding mode control (SMC) is proposed to track the speed of the sleeve quickly and precisely during the synchronization process, which takes 0.18s and maintains a speed difference of around 1 rpm. Furthermore, a Kalman Filter is utilized to overcome the difficulties associated with side shaft torque measurement and low wheel speed resolution. A simulation is performed in MATLAB/SIMULINK, and the powershift (2nd -&#x003E; 3rd) is compared with other methods. The comparison indicates that the proposed power shift strategy can reduce the maximum jerk from 14.8 m/s3 to 5.6 m/s3, while the entire shifting process lasts for 0.71s. Therefore, the proposed power shift control strategy effectively improves the shift quality.

Передача крутящего момента проводящей частице с использованием силы Лоренца

In the paper the concept of conductive particle rotation in DC electric field with including the Lorentz force providing generation of electric dipole moment of the particle is for the first time discussed. Some models of the torque transfer to spherical and cylindrical particles based on of the Hall effect at usual geometry and with additional electric field application and also in the case of implementation of the photoelectromagnetic effect are presented.

Intelligent Torque Allocation Based Coordinated Switching Strategy for Comfort Enhancement of Hybrid Electric Vehicles

This paper proposes two intelligent torque distribution strategies based on particle swarm optimization (PSO) and fuzzy logic control (FLC) to provide convenient torque allocation that maximizes hybrid electric vehicle (HEV) propulsion power. PSO torque distribution strategy uses torque transfer ratio (TTR) as a fitness function to select the best torque candidates and differential arrangements that maximize HEV propulsion torque. A proposed FLC controller with adequate membership functions is designed to ensure convenient torque vectoring across vehicle wheels. New coordinated switching strategy is proposed in this paper to address the undesired transient ripples occurring during drivetrain commutations and power source switchings. The proposed coordinated switching strategy controls the switching period duration through transition functions fitting the transient dynamics of power sources. In non-uniform surfaces, intelligent torque allocation strategies converted 84&#x007E;86% of the generated torque into propulsion torque whereas equal torque distribution strategy yielded a torque transfer ratio of 50%. Thanks to the proposed coordinated switching strategy, DC bus voltage ripples were reduced into a narrow band of &#x00B1; 5V, transient power ripples were limited to a narrow band of 600 W and torque jerks were almost suppressed. Real-time simulation using the RT LAB platform confirms that the proposed coordinated switching strategy have reduced transient torque overshoot from 69% to almost zero and this is expected to improve HEV driving comfort.

Torque transfer to conductive particle using the Lorentz force

In the paper the concept of conductive particle rotation in DC electric field with including the Lorentz force providing generation of electric dipole moment of the particle is for the first time discussed. Some models of the torque transfer to spherical and cylindrical particles based on of the Hall effect at usual geometry and with additional electric field application and also in the case of implementation of the photoelectromagnetic effect are presented. Keywords: Lorentz force, Hall effect, electric dipole, torque.