Equivalent Torque Research Articles

Justifying and Implementing Concept of Object-Oriented Observers of Thermal State of Rolling Mill Motors

Implementing the IIoT concept in industry involves the development and implementation of online systems monitoring the technical state of electromechanical equipment. This is achieved through the use of digital twins and digital shadows (object state observers). The tasks of mastering new rolling profiles and optimizing plate mill rolling programs require improved methods for calculating equivalent motor currents and torques. Known methods are generally based on calculations using smoothed load diagrams, which are assumed to be identical for the upper and lower main drive (UMD and LMD) rolls. These methods do not consider the differences in actual loads (currents or torques) in steady rolling states. Experiments performed on the 5000 plate mill have shown that due to speed mismatches, the UMD and LMD torques differ three times or more. This causes overheating of the more heavily loaded motor, insulation life reduction, and premature failure. Therefore, the problem of developing and implementing techniques for monitoring the load and thermal regimes of motors using digital observers is relevant. The paper’s contribution is the first justification of the concept of object-oriented digital shadows. They are developed for specific classes of industrial units using open-source software. This research justifies a methodology for assessing motor load and temperature by processing arrays of motor currents or torques generated during rolling. An equivalent load observer and a temperature observer were proposed and implemented using Matlab-Simulink resources. The algorithm was implemented on the mill 5000 and tuned using an earlier-developed virtual commissioning methodology with digital twins. Thermal regimes were studied, proving that torque alignment ensures equal motor temperatures. The proposed considerations contribute to the development of the theory and practice for creating digital systems to monitor the technical condition of electromechanical and mechatronic systems and implementing the Industry 4.0 concept at industrial enterprises.

Analysis of secondary makeup characteristics of drill collar joint and prediction of downhole equivalent impact torque of Well SDTK1

Based on the three-dimensional elastic-plastic finite element analysis of the 8” (203.2 mm) drill collar joint, this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions, as well as the downhole secondary makeup features, and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads. On the basis of verifying the correctness of the calculation results by using measured results in Well GT1, the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10 000 m in China (Well SDTK1). The results indicate that under complex loads, the stress distribution in drill collar joints is uneven, with relatively higher von Mises stress at the shoulder and the threads close to the shoulder. For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards, when the downhole equivalent impact torque exceeds 65 kN·m, the preload balance of the joint is disrupted, leading to secondary make-up of the joint. As the downhole equivalent impact torque increases, the relative offset at the shoulder of internal and external threads increases. The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment. It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque, and effectively prevent drilling tool failure.

Utilizing phased array ultrasound technique to examine seal surface contact status in premium connections

Premium connections are commonly employed in wells subjected to high temperature and high pressure (HTHP) conditions. The key parameter in evaluating the sealing capability of premium connections is the contact condition between the sealing surface. This paper presents a method based on phased array ultrasound testing (PAUT) technique to examine the metal-to-metal contact states of the seal surface in premium conditions, and presents experimental work on contact status of the seal surface in premium tubing connections using PAUT, testing impacts of torque, seal surface defects and thread compounds dosage. The experimental findings demonstrate an inverse relationship between the observed ultrasonic reflection amplitude and the applied torque on the premium. Additionally, there is a robust exponential correlation manifested between the ultrasonic reflection amplitude and the torque exerted on the premium. The ultrasonic reflection amplitude at the defect of the seal surface increases. Under equivalent make-up torque conditions, the ultrasonic reflection amplitude on the sealing surface of premium connections escalates as the dosage of thread compounds diminishes, and the importance of precise control of the amount of thread compound used was confirmed. These data demonstrate that PAUT provides a reliable detection technique for performance assessment on premium connections, both in quality control and field inspection.

Manipulation of high-frequency spin waves in ferromagnetic thin films via magnetic torques induced by ultrafast demagnetization

Spin-based technologies demand the effective excitation and control of high-frequency spin waves in order to increase the operational speed of magnonic logic circuits. An available option for the high-frequency spin wave is the perpendicular standing spin waves (PSSWs) in ferromagnetic thin films. However, the practical utilization of a PSSW is still challenging due to a few unsolved critical issues such as its relatively low amplitude and simultaneous excitation of other PSSW modes. Here, efficient excitation and control of a first-order PSSW mode are demonstrated in Ni80Fe20 thin films using a double-laser-pulse scheme. Based upon our experimental and theoretical investigations, it is found that the precession amplitudes of the Kittel and PSSW modes show strong dependence on equivalent torques (i.e., the averaged torques during fast relaxation process after the second pulse excitation) applied to these two modes. Thus, selective excitation and amplification of the first-order PSSW mode can be realized by manipulating the equivalent torque, i.e., introducing a second laser pulse with an appropriate arrival time and laser fluence. Moreover, the spectral tuning of this single PSSW mode can be achieved by proportionately adjusting the laser fluence of two pump pulses. These findings may pave the way for the realization and construction of future high-performance spintronic devices.

Steering ability rapid evaluation of the slide drilling system based on multi-body dynamics model

Efficiently and accurately predicting the steering ability of the bottom hole assembly (BHA) in slide drilling is a crucial yet challenging task. While the industry standard three-point geometry method is computationally efficient, it cannot capture the intricate mechanics involved in the drilling process. Conversely, utilizing the whole drill string dynamics model for simulating slide drilling provides a more comprehensive representation but involves time-consuming evaluations, making it difficult to balance precision and efficiency. This study addresses this challenge by proposing a rapid evaluation method that ensures both speed and accuracy by developing a multi-body dynamics rapid model of the slide drilling system. Based on the whole drill string model, this method incorporates two key techniques to achieve its primary objective. Firstly, it utilizes the equivalent torque model of the bit, which includes the fixed joint and the virtual rotational velocity, to replace the original revolute joint between the positive displacement motor (PDM) and the bit. Secondly, a segmentation model is established to decouple the simulation of the BHA drilling process from the drill string equilibrium process, thereby significantly reducing the slide drilling system’s degree of freedom (DOF). The proposed method offers a new approach to improving the efficiency of evaluating the steering ability of the slide drilling system while ensuring a high level of accuracy.

Flexible modeling and dynamics simulation of four-bar beating-up system with clearance

To explore the actual working characteristic of the beating-up mechanism on looms, the Step function is adopted to convert the beating-up resistance to an equivalent torque acting on the rocking shaft, and a new method of calculating and simulating the resistance is hereby raised. In accordance with the two-state joint clearance, the paper establishes a double-side model of the four-bar beating-up system in clearance status via ADAMS/View software, and under the consideration of both beating-up resistance and flexible deformation conditions, the contact simulation of beating-up motion with different clearances (0.01∼0.12 mm) is achieved. The main findings are as follows: the actual working condition could be reflected more accurately if the beating-up resistance and component flexibility are included into the simulation computing; from the perspective of the impact on sley moving and beating-up loads, 0.08 mm clearance is obviously less then another three clearances (0.01 mm, 0.04 mm and 0.12 mm); the multi-point contact and collision with peak load greater than 4000 N is existed in connecting rod bearing in the 0∼350 Hz low frequency area, which is likely to exacerbate the wear and fatigue rupture of the bearing; the dynamic shock load of rocking shaft on the loom frame is far greater than that of the crankshaft, indicating that the rocking shaft is the main carrier for delivering the beating-up power; compared to the clearance of 0.08 mm and 0.12 mm, the dynamic impact load generated by the clearance of 0.01 mm and 0.04 mm on the loom frame is obvious greater. In addition, under the clearance condition, transverse vibration could be occurred for the flexible crankshaft due to the deviation of its centroid trajectory, which is detrimental to vibration and noise reduction for the loom system. On the basis of the work, a number of viewpoints with theoretical and practical significance could be provided to the design of beating-up system on the loom with clearance.

Design Method of Full-scale Fatigue Test Load for Wind Turbine Blade

The blade is one of the key components of a wind turbine, and the alternating fatigue load is the main factor leading to the fatigue failure of wind turbine blades. The accuracy of load determines the accuracy of the wind turbine blade test. Based on the equivalent torque time history data from the wind load acting on the blade root, the load of the two-dimensional matrix is obtained by using data compression technology and a rain flow counting algorithm. According to the capture matrix of load data, the frequency of various design loading cases and the distribution of wind speed, the symmetrical load spectrum is calculated and compiled. The fatigue load of a wind turbine blade is calculated for a certain type of 2MW blade, which lays a foundation for the design and test of a wind turbine blade fatigue loading system.

A Novel Three-Stage Optimization Design Method of Asymmetric-PM Variable Flux Memory Machine Considering Magnet-Axis-Shifting Effect

Asymmetric-permanent-magnet variable flux memory machine (APM-VFMM) commonly suffers from the optimization issues, i.e., variable magnet-axis-shifting (MAS) effects result in distinctly differentiated electromagnetic characteristics under multiple magnetization states (MSs). Thus, this article proposes a novel three-stage optimization method for APM-VFMM considering the MAS effects to achieve efficient optimization. In the first stage, an analytical model based on the magnetic equivalent circuit (MEC) and torque models considering the MAS effects is developed to determine the key optimization objectives of the investigated machine while theoretically revealing the internal mechanisms for the improvement of the flux regulation range and torque capability. In the second stage, the comprehensive sensitivity analyses of the main geometric parameters are implemented based on a self-organizing map (SOM) method. Subsequently, the geometric parameters with higher sensitivity are selected for the multiobjective optimization process, thus effectively reducing the computational burden. In the third stage, a multimode circuit control model is developed and utilized in a single finite element analysis (FEA) case to consider multiple MSs and different MAS effects simultaneously for multiobjective optimization. The FEA predictions and experimental tests carried out on an APM-VFMM prototype confirm the effectiveness of the proposed three-stage optimization method.

Relaxation of static load bolt and its influence on early accuracy decline of guideway

The straightness error of guideway connected with machine bed can exceed the allowable value due to the pretension relaxation in bolted joints. It is inevitable that the relaxation caused by creep displacement of contact surfaces at ambient temperature. The spring and damping elements are introduced to equivalent the contact surfaces. A mathematical model is established for characterizing the relaxation. The effects of equivalent parameters, surface roughness, and initial tightening torque on pretension relaxation are ulteriorly analyzed. It is found that the relaxation degree of pre-tightening force increases with increase of elastic element stiffness, surface finish, and initial tightening torque. The straightness of guideway subjected to different bolt preloads is studied based on the finite element method (FEM). Finally, experiments are conducted to verify the proposed model and FEM. The results show that the model error is 6.67%, and the straightness error in horizontal/vertical direction is 7.79%/7.28%.

A Model Predictive Control Approach for Electro-Hydraulic Braking by Wire

In this article, based on a novel electro-hydraulic braking system for full self-driving vehicles, a model predictive control approach is designed for precisely tracking of braking pressure. Concerning electric motor, reduction mechanism, and hydraulic system, a new braking system model is formulated. Due to the nonlinear hydraulic characteristic of the master cylinder piston, a quadratic polynomial is utilized to fit a relationship between piston position and cylinder pressure, by which a desired pressure of master cylinder is transformed into a desired position of the piston. A recursive least square with forgetting factor is developed to find the optimal parameters of pressure–position relationship. A system friction model is established to calculate the equivalent friction torque, which is regarded as the compensation of the desired torque. A vehicle test bench of full self-driving is established to validate the designed approach. According to the accurate tracking and the quick response of braking pressure from experimental results, it can be concluded that the model predictive control approach is a good candidate for the pressure demand control of electro-hydraulic braking by wire.

Sensibilization of a motorcycle simulator to the effects of the roll motion: Modelling and experimental validation

When riding a motorcycle, the applied steering torque and the lateral rider body movement influence its trajectory. Reproducing the effect of body and motorcycle roll on a simulator would improve its realism. However, this goal is still challenging, especially on low-complexity simulators such as the MOVING simulator of the University of Florence. In order to achieve this result, this study defined a control logic to introduce steering effects linked with the mockup passive inclination operated by the rider. The logic computed a roll-related steering input consisting of equivalent steering torque. This contribution was added to that the rider exerted on the handlebar. A validation test with participants revealed improvements over the baseline, roll-insensitive approach, especially in stationary and medium-high speed manoeuvres. Interestingly, the riders unconsciously tended to use larger mockup roll angles as the roll sensitivity increased. The logic was optimised for stationary manoeuvres; however, the subjective feedback provided by the participants indicated a good level of riding realism also during transients. This simple and effective logic opens the way for new methodologies to improve the realism of motorcycle simulators, encouraging their development and use.

Dynamic analysis of a three-fingered deployable metamorphic robotic grasper

This paper selects a three-fingered deployable metamorphic robotic grasper as the studied object and presents a distributed dynamic modeling method for the multi-body system based on the metamorphic mechanism. Considering that the grasper contains two independent motion configurations, dynamic models of them are independently established, and then the final dynamic model of the whole grasper is formed. To further improve the modeling accuracy, it is creatively proposed that irregular links can be seen as rigid connections of multiple regular links, by which the dynamic model for the deployment motion of the grasper is firstly established via the Lagrange equation. For the grasping motion, since the finger of the grasper can be equivalent to a planar 4R serial mechanism, the dynamic models of the base mechanism and the basic module are established by the Lagrange equation to obtain the relationships between the driving forces and the equivalent torques. The whole grasper is then established by the recursive Newton-Euler method to enhance the modeling efficiency. Finally, the effectiveness of the dynamic model is well verified by the dynamic simulation.

Development of a fatigue strength testing machine

A profound engineering design and modeling of fatigue strength machine for testing the failure which occurs when a metallic material is subjected to cyclic stresses is presented. The main goal is developing a locally made fatigue strength machine that can be used in material science laboratory. A major direction in this development of the machine is the ability to thread on the path of technology transfer and dominance by concentrating on the building of indigenous capacity. In carrying out the machine development, engineering design formulae were applied and Computer Aided Design modeling was developed. The developed fatigue strength testing machine had a designed machine capacity of 18875Nmm that sustained a motor power of 5.93kw.The machine shaft diameter determined to be 9.88mm developed an equivalent torque and bending moment of 45799.8Nmm and 40890Nmm respectively. The machine designed critical speed of 23.52rad/s had belt tensions on the tight and slack sides to be 139.02N and 44.65N respectively. The fabricated machine has the ability to record low and high fatigue cycles.

Nonlinear motor-mechanism coupling tank gun control system based on adaptive radial basis function neural network optimised computed torque control

This study investigates the spatial pointing control of a motor-mechanism coupling tank gun. The tank gun control system (TGCS) is driven and stabilised by the motor servo system. However, complicated nonlinearities in the TGCS are inevitable, such as friction, parameter uncertainty, and modelling errors. To solve this problem, the TGCS is regarded as a coupling system composed of mechanical, motor, and control systems. Accordingly, the mechanical and motor models of the marching tank gun are developed first in this paper. The motor-mechanism coupling dynamics model is established based on the principle of equivalent torque. On this basis, a computed torque controller, whose uncertainty was estimated using a radial basis function neural network (RBFNN), is constructed. A modified adaptive algorithm is used to estimate the weights of the RBFNN, and the estimation error of the uncertain observer is compensated by a compensation controller. Simulation results under different conditions validated the effectiveness of the proposed control system, revealing that the proposed control system has good tracking accuracy, strong adaptability, and robustness.

Modeling and Validation of a Passive Truss-Link Mechanism for Deployable Structures Considering Friction Compensation with Response Surface Methods

In this study, a passive truss-link mechanism applicable to large-scale deployable structures was designed to achieve successful deployment in space. First, we simplified the selected truss-link mechanisms to the two-dimensional geometry and calculated the degrees of freedom (DOF) to determine whether a kinematic over-constraint occurs. The dimensions of the truss-link structure were determined through a deployment kinematic analysis. Second, a deployment simulation with the truss-link was conducted using multibody dynamics (MBD) software. Finally, a deployment test was performed considering gravity compensation, and the results were compared with those of MBD simulation. The results of the deployment simulations were confirmed to be slightly faster than those of the deployment test due to friction effects existing in the joints and gravity compensation devices. To address this issue, inverse identification of the equivalent frictional torque (EFT) at the revolute joints in the deployment test was conducted through response surface methods (RSM) combined with the central composite design technique. As a result, we confirmed that the deployment angle history of the deployment simulation was similar to that of the deployment test.

Effects of Local Gravity Compensation on Motor Control During Altered Environmental Gravity.

Our sensorimotor control is well adapted to normogravity environment encountered on Earth and any change in gravity significantly disturbs our movement. In order to produce appropriate motor commands for aimed arm movements such as pointing or reaching, environmental changes have to be taken into account. This adaptation is crucial when performing successful movements during microgravity and hypergravity conditions. To mitigate the effects of changing gravitational levels, such as the changed movement duration and decreased accuracy, we explored the possible beneficial effects of gravity compensation on movement. Local gravity compensation was achieved using a motorized robotic device capable of applying precise forces to the subject’s wrist that generated a normogravity equivalent torque at the shoulder joint during periods of microgravity and hypergravity. The efficiency of the local gravity compensation was assessed with an experiment in which participants performed a series of pointing movements toward the target on a screen during a parabolic flight. We compared movement duration, accuracy, movement trajectory, and muscle activations of movements during periods of microgravity and hypergravity with conditions when local gravity compensation was provided. The use of local gravity compensation at the arm mitigated the changes in movement duration, accuracy, and muscle activity. Our results suggest that the use of such an assistive device helps with movements during unfamiliar environmental gravity.

Modeling of Visco-Elastic Environments for Humanoid Robot Motion Control

This manuscript presents a model of compliant contacts for time-critical humanoid robot motion control. The proposed model considers the environment as a continuum of spring-damper systems, which allows us to compute the equivalent contact force and torque that the environment exerts on the contact surface. We show that the proposed model extends the linear and rotational springs and dampers - classically used to characterize soft terrains - to the case of large contact surface orientations. The contact model is then used for the real-time whole-body control of humanoid robots walking on visco-elastic environments. The overall approach is validated by simulating walking motions of the iCub humanoid robot. Furthermore, the paper compares the proposed whole-body control strategy and state of the art approaches. In this respect, we investigate the terrain compliance that makes the classical approaches assuming rigid contacts fail. We finally analyze the robustness of the presented control design with respect to non-parametric uncertainty in the contact-model.

Parameter Estimation of a Countershaft Brake for Heavy-Duty Vehicles with Automated Mechanical Transmission

A countershaft brake is used as a transmission brake (TB) to realize synchronous shifting by reducing the automated mechanical transmission (AMT) input shaft’s speed rapidly. This process is performed to reduce shifting time and improve shifting quality for heavy-duty vehicles equipped with AMT without synchronizer. To improve controlled synchronous shifting, the AMT input shaft’s equivalent resistance torque and the TB’s characteristic parameters are studied. An AMT dynamic model under neutral gear position is analyzed during the synchronous control interval. A dynamic model of the countershaft brake is discussed, and its control flow is given. The parameter identification method of the AMT input shaft’s equivalent resistance torque is given on the basis of the least squares algorithm. The parameter identification of the TB’s characteristic parameters is proposed on the basis of the recursive least squares method (RLSM). Experimental results show that the recursive estimations of the TB’s characteristic parameters under different duty cycles of the TB solenoid valve, including brake torque estimation, estimation accuracy, and braking intensity estimation, can be effectively estimated. The research provides some reliable evidence to further study the synchronous shifting control schedule for heavy-duty vehicles with AMT.

전동지게차용 Steering Axle의 구조해석 및 가속수명시험방법 적용

Purpose: This paper introduces the procedure and results of a durability test conducted for the steering axle of a two-ton electric forklift. The test is designed as an accelerated life test based on the reliability analysis standard RS B 0073, established by the Korea Institute of Machine and Materials.BRMethods: We conducted an accelerated life test that can simultaneously check the durability of the gear and housing through a tester that applies a load to the steering axle. The test was performed for a total of 360 h, with 11 h test cycle each in the forward and reverse directions under the proposed test code with a rotation speed of 2,300 rpm and an equivalent torque of 2.07 Nm. Subsequently, visual verification and gear precision measurements were performed through sample disassembly.BRResults: Altuough minor rubbing marks and gear bites were observed, no significant damage or deformation of the surface fittings was identified. A penetration test confirmed that there was no crack in the housing due to stress.BRConclusion: This paper provides guidelines for testing the life of steering axles.

Estimation of the Life of Spiroid Gears by Wear Taking into Account the Equivalent Torque

Обоснована целесообразность применения спироидных передач в приводах и механизмах подъемно-транс­портных и строительных машин. Отмечены характерные достоинства указанных передач, позволяющие проектировать приводы машин с улучшенными технико-экономическими показателями.Приведены сведения об основных производителях спироидных передач в России и за рубежом.Представлено краткое описание и анализ основных причин выхода из строя механизмов и приводов машин на основе передач зацеплением, а также передач червячного класса в результате их эксплуатации и действия контактных нагрузок на активных поверхностях зубьев зубчатых колес, что приводит к неисправностям, поломкам, отказам в виде износа, задиров, истирания. Описан существующий метод расчета на выносливость с учетом графика изменения значений нагрузок и количества циклов их действия на контактную выносливость и на выносливость зубьев при изгибе, используемый при расчетах на прочность прямозубых и косозубых цилиндрических передач.Обоснована необходимость создания метода оценки по износу спироидных передач с учетом ступенчатого режима действия нагрузок на основе анализа режимов эксплуатации приводов подъемно-транспортных машин и оборудования, где применяется данный вид передач.Предложенный метод проиллюстрирован примером расчета ресурса спироидного редуктора тяговой лебедки укладочного крана.