Torque Measurement Method Research Articles

A nN[formula omitted]m level micromotor holding torque measurement method

Efficient and high-precision torque measurement methods for micromotors are globally critical, impeding the advancement of microsystems, particularly ultrasonic micromotors, known for their small size, high speed and high resolution. This paper proposes a novel torque measurement method for ultrasonic micromotors, establishing a torque measurement device that utilizes a parallelogram flexible hinge as the force transmission element. This approach can measure torque at the nano-Newton-meter (nN⋅m) level. The system demonstrates high measurement accuracy, robust anti-interference capability, and a wide measurement range. When the 18 V voltage is applied to the motor, the holding torque is 234.66 nN⋅m, the repeatability error of the system is 1.25%, and the combined standard uncertainty is 5.36 nN⋅m. The proposed method is a pivotal step towards filling the existing technological void, offering a substantial impact on the development of ultrasonic micromotors and the broader field of microsystems.

Research on torque measurement in flight test for all-moving horizontal tail based on spiral driver

PurposeTorque is one of the main loads acting on the aircraft wing, the horizontal tail and the vertical tail. In flight load measurement, due to the significant influence of the bending moment and the shear force on the strain gauge, the accuracy of torque measurement is usually low. Therefore, aircraft torque measurement is difficult. Based on the characteristics of a certain type of horizontal tail, a measurement method for the torque with high accuracy was proposed in this paper.Design/methodology/approachA new simplified torque measurement method for the all-moving horizontal tail was proposed based on the spiral driver. The feasibility of the method and key points of the tests were analyzed and studied through a virtual load calibration test.FindingsBased on the results of the real load calibration test, the torque load equation with high accuracy was established, and the torque measurement was achieved in load flight tests.Research limitations/implicationsHowever, the proposed method is based on the structure of the spiral driver. If there is generally no spiral driver at the aircraft wings and vertical tails, then the appropriate torque measurement method needs to be derived according to the specific object.Originality/valueThe research in this paper provides a new idea for the torque measurement of aircraft structures, which can be used for the torque measurement of subsequent aircraft types.

Clinical study on freehand of bicortical sacral screw fixation with the assistance of torque measurement device

BackgroundSacral screw loosening is a typical complication after internal fixation surgery through the vertebral arch system. Bicortical fixation can successfully prevent screw loosening, and how improving the rate of bicortical fixation is a challenging clinical investigation.ObjectiveTo investigate the feasibility of improving the double corticality of sacral screws and the optimal fixation depth to achieve double cortical fixation by combining the torque measurement method with bare hands.MethodsNinety-seven cases of posterior lumbar internal fixation with pedicle root system were included in this study. Based on the tactile feedback of the surgeon indicating the expected penetration of the screw into the contralateral cortex of the sacrum, the screws were further rotated by 180°, 360°, or 720°, categorized into the bicortical 180° group, bicortical 360° group, and bicortical 720° group, respectively. Intraoperatively, the torque during screw insertion was recorded. Postoperatively, the rate of double-cortex engagement was evaluated at 7 days, and screw loosening was assessed at 1 year follow-up.ResultsThe bicortical rates of the 180° group, 360° group, and 720° group were 66.13%, 91.18% and 93.75%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05).The rates of loosening of sacral screws in the 180° group, 360° group, and 720° group were 20.97%, 7.35% and 7.81%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05). The bicortical 360° group achieved a relatively satisfactory rate of dual cortical purchase while maintaining a lower rate of screw loosening.ConclusionManual insertion of sacral screws with the assistance of a torque measurement device can achieve a relatively satisfactory dual cortical purchase rate while reducing patient hospitalization costs.

Torque measurement during stirring process research on the pilot plant

This article deals with the torque measurement mechanism of the mechanical stirring process. The resulting shear stresses or strains measure the torque. The authors provide a torque meter classification and various methods of torque measurement to accurately measure and control torque. They are important parameters in the design and manufacture of various devices and mechanisms. The paper presents a schematic diagram of a pilot plant to investigate mechanical stirring using the developed torque measurement device without the use of a stroboscope. The method proposed by the authors solves the problem related to simplification of technical torque measurement. The authors calculated the range of liquid level change in the piezometer during the study of the stirring process at the pilot plant, taking into account the minimum and maximum values of pressure in the vessel.

A novel cogging torque measurement method for multi slot/pole permanent magnet motor

AbstractThe adverse effect on speed ripple and vibration makes it necessary to evaluate the cogging torque. Due to the tolerance of stator and rotor stacks as well as nonuniform magnetization of permanent magnet, the amplitude of cogging torque is unequal in different rotor position. As a result, the verification of theoretical analysis becomes difficult. Therefore, the cogging torque average is used to weigh it. In view of the large least common multiple of multi slot/pole Permanent magnet motor, which means, there are multiple cogging torque cycles per rotor revolution, a cogging torque measurement method is proposed. Through simple devices such as arm, weight, digital gauge, resolver, and so on, the amplitude and period of cogging torque can be accurately measured without site restrictions. The correctness of the method is verified by simulation and experiment, and that can be used as a supplement to cogging torque evaluation for multi slot/pole PMM.

ALGORITHM FOR DETERMINING THE TORQUE OF ELECTRIC MOTORS USING INDIRECT MEASUREMENT METHODS

Indirect torque measurement methods can be performed in a variety of ways, depending on the specific situation and available tools. One such way is to measure the displacement, or speed of rotation of the shaft and use this information to calculate the moment using the moment of inertia equation. For this, it is necessary to know the moment of inertia and the angular acceleration, which can be measured using a gyroscope or accelerometer. Another way is to measure the voltage and current in the electrical circuit connecting the motor and the power source by determining the power of the electric motor. However, indirect methods of measuring torques of electric motors are based on the measurement of other physical parameters that correlate with torque, such as current, voltage, rotation frequency, etc. These methods are often used because of their cost-effectiveness and ease of implementation, but they have some drawbacks. In particular: indirect methods are usually less accurate than direct methods because they depend on mathematical models and correlations between different parameters, which may be imprecise or incomplete; parameters that are measured by indirect methods may be influenced by external factors, which may affect the accuracy of measurements; calibration of devices is usually carried out in laboratory conditions, so the results may not reflect real operating conditions; the mathematical models used to determine the torque may be non-linear. This can lead to errors in measurements, especially at high or low torque values; indirect methods do not provide direct feedback about the real torque, which can lead to delays in process regulation and control. This can be critical for some applications where fast and accurate torque control is essential; indirect methods may be less efficient or unsuitable for some types of electric motors or applications. For example, when using high-frequency or multiphase motors, indirect methods may not provide sufficient accuracy or stability of measurements. The article examines algorithms for determining the rotational parameters of electric motors using indirect measurement methods. An analysis of the characteristics of electric motors according to their energy data was carried out. The measurement possibilities are determined based on the functional dependence of the torque on the power of the electric motor and the speed of rotation of its shaft. The characteristics of the power components are studied and the results of their simulation are given. An analysis of the methods of determining the angular velocity and angular acceleration of the electric motor shaft was carried out, and the role of these parameters in the determination of the torque was investigated. A two-channel network-type information and measurement system is proposed, which allows data collection and their visualization, where one channel is used to measure power, the other to measure shaft rotation speed.

Preload measurement of steel-to-timber bolted joint using piezoceramic-based electromechanical impedance method

Steel-to-timber bolted connections play an essential role in enabling glulam column and beam to work together. However, these connections are prone to bolt looseness due to shrinkage and creep effects of timber material during a long service life, which may cause consequent connection failures and structural safety hazards. Recently, detection and evaluation of bolt looseness have gained considerable attention, whereas the existing vision-based method is challenging to inspect early bolt looseness, and the percussion-enabled approach is susceptible to being affected by harsh environmental noises. Thus, in this study, the authors proposed a pre-tightening torque measurement method for steel-to-timber bolted connection based on variations of electromechanical impedance (EMI) of designed Lead Zirconate Titanate (PZT) sensors. A theoretical formula is derived first based on the piezoelectric equation and boundary conditions to illustrate the feasibility of using EMI variations to reflect looseness levels. Moreover, a sensor that can be easily integrated into the steel-to-timber connection and work as a washer is designed and fabricated. Consequently, the environmental performance against temperature and humidity of designed sensors is investigated by preliminary tests. Based on preliminary tests results, a frequency range that showed lower environmental sensitivity is selected as the excitation signal in the following bolt looseness measuring experimental studies. Experimental results well validate the effectiveness of EMI method in the monitoring of pre-tightening torque of steel-to-timber bolted connections, showing a great potential to inspect preload looseness of glulam structures in field applications.

A model formulation for the prediction of churning power loss in worm gear transmission

Churning power loss is a complex process that causes significant loss of energy under splash lubrication of gear units. A set of empirical equations are available that allows for precise churning power losses calculation for only the parallel axis gears. The main objective of this study is to formulate a new mathematical model for worm gear based on the experiment result. The mathematical model is formulated using the dimensional analysis method and has been experimentally validated over a wide range of speeds in terms of revolutions, types of lubricants, lubricant temperature, and immersion depths. The simple direct torque measurement method was used to measure the churning loss. The influence of inertia force, viscous force, and gravitational forces were also investigated therefore correlations with Froude and Reynolds numbers are presented. Hardened steel and bronze were used as a material combination of worm and worm gear, respectively. A new formula for worm gear under splash lubrication has been derived and validated by comparison with experimental evidence. A very little discrepancy was found between the experiment result and the mathematical equation.

Comparative Study on the Power Consumption and Flow Field Characteristics of a Three-Blade Combined Agitator

The three-blade combined agitator consists of two propulsion blades of the same type (including planar propeller blades b, δ = 36.87°) and a curved blade (θ = 30°). Using numerical simulation methods, the power characteristics, flow field distribution, turbulence characteristics and dead zone percentage of two kinds of three-blade combined agitators (TBCAs) from laminar flow to turbulent flow in a mixing vessel were studied. Moreover, the torque measurement method was used to perform experimental verification. The results show that the predicted power curve is consistent with the experimental results. The fluid velocity near the propeller blades in the TBC-B type agitator (δ = 36.87°) is significantly high, and the maximum increase of the total velocity can reach 30.3%. The fluid flow velocity near the curved blades is increased, and the radial diffusion ability of the fluid at the bottom of the stirring vessel is enhanced. When mixing low-viscosity fluids, the TBC-B type agitator can increase the fluid velocity near the paddle area, with a maximum increase of 22.1%. The vertical combination of curved blades and planar propeller blades can effectively reduce the tangential velocity and increase the axial and radial velocities. When stirring high-viscosity fluids, the speed of the TBC-B type agitator in the near paddle area and far end of the blade is higher than that of the TBC-A type agitator. Under the same conditions, the TBC-B-type agitator exhibits superior fluid discharge performance and can be used in a wider range of viscosities. When Re = 44,910, the dead zone percentage of the TBC-A type agitator is 0.0216. The percentage of dead zones produced by the TBC-B-type agitator is smaller, and the mixing effect is superior to that of the TBC-A-type agitator.

Torque Measurement Technology by Using a Magnetostrictive Ring and Multiple Magnets

A torque measurement method that combines the inverse magnetostrictive effect with twist angle measurement has been proposed in this paper. A Kalman filter and complementary filter are applied to significantly reduce the noises and errors in the proposed method. This new measurement block can detect the applied torque with an error of less than 1%. The proposed measurement method can be used in static and dynamic conditions.

An overview of torque meters and new devices development for condition monitoring of mining machines

Condition monitoring and diagnostics of minerals mining machines is a challenging task for operating companies and their maintenance staff. Conventional approaches based on measurements of vibration, temperature and other parameters are still not widely implemented in the mining industry due to non-stationary loading conditions. Registration of overloading and resonance modes is not sufficient by the electrical motors current in case of heavy mobile vehicles or stationary mounted mining machines having multi-body structure. Telemetric torque measurement tools installed in the drivetrains of mining machines allow accounting the variation of loads and gives valuable information on damages in geared transmissions. This paper represents the different methods of torque measurement and digital telemetry device under development based on strain gauges. The focus is on the functionality required for industrial applicability and issues in course of machines operation and maintenance. The additional features, which the torque meters afford for mining machines diagnostics, are considered.

Kalman filter-based loading rate-dependent hysteresis compensation of flexoelectric torsional responses in polyvinylidene fluoride films for shaft torque sensors

This paper presents a new method of dynamic shaft torque measurement using polyvinylidene fluoride (PVDF) films, one of the new polymer type piezoelectric conversion materials. The measurement method is based on the shear strain gradient and the flexoelectric torsional response of the PVDF films. The loading rate-dependent hysteresis associated with viscoelastic behavior of PVDF film was modeled to estimate the torque input. The torque estimated by the proposed hysteresis model and optimization algorithm (genetic algorithm) can be implemented by the discrete Kalman filter. Because the torque estimated by the real-time Kalman filtering matches well with the actual torque input measured by the commercial in-line torque transducer, a new method of sensing the dynamic shaft torque using the PVDF output signal has been experimentally validated. This study offers potential applications for the development of new torque sensing technology to be widely used in a variety of mechanical engineering areas such as turbines, rotors, automobiles, and robotics.

Development of a Prediction Model for Tractor Axle Torque during Tillage Operation

In general, the tractor axle torque is used as an indicator for making various decisions when engineers perform transmission fatigue life analysis, optimal design, and accelerated life testing. Since the existing axle torque measurement method requires an expensive torque sensor, an alternative method is required. Therefore, the aim of this study is to develop a prediction model for the tractor axle torque during tillage operation that can replace expensive axle torque sensors. A prediction model was proposed through regression analysis using key variables affecting the tractor axle torque. The engine torque, engine speed, tillage depth, slip ratio, and travel speed were selected as explanatory variables. In order to collect explanatory and dependent variable data, a load measurement system was developed, and a field experiment was performed on moldboard plow tillage using a tractor with a load measurement system. A total of eight axle torque prediction regression models were proposed using the measured calibration dataset. The adjusted coefficient of determination (R2) of the proposed regression model showed a range of 0.271 to 0.925. Among them, the prediction model E showed an adjusted R2 of 0.925. All of the prediction models were verified using a validation set. All of the axle torque prediction models showed an mean absolute percentage error (MAPE) of less than 2.8%. In particular, Model E, adopting engine torque, engine speed, and travel speed as variables, and Model H, adopting engine torque, tillage depth and travel speed as variables, showed MAPEs of 1.19 and 1.30%, respectively. Therefore, it was found that the proposed prediction models are applicable to actual axle torque prediction.

Torque and rotational speed sensor based on resistance and capacitive grating for rotational shaft of mechanical systems

Torque and rotational speed are important parameters to characterize the power of rotating parts for mechanical systems, so a rotational shaft’s torque and rotational speed sensing method and real-time signal processing are key technologies for mechanized equipment, such as vehicles, ships, etc. Hence an advanced torque and speed sensing technology and a data processing technology are very important for improving the performance of mechanical equipment. However, the power transmission device’s rotational shaft has a compact structure and narrow space, so it is difficult to install a signal transmission and power supply device of a sensor on the rotational shaft. To solve these difficult problems, this paper proposes a rotational shaft torque and rotational speed measurement method coupling resistance and capacitance. This method uses two resistance strain gauges and a capacitive grating, and the capacitive grating transmits signals in a non-contact coupling manner. The sensor on the rotational shaft needs no power supply and the signals are transmitted to a measurement circuit from a stationary sleeve, so this method essentially solves the difficult problems in signal transmission and power supply. Simulation and measurement experiments show that the resistance strain gauges obtain information and the capacitive grating sensor transfers information. The method coupling resistance and capacitance for realizing information sensing is feasible, which is suitable for measuring the torque and rotational speed of the rotational shaft of mechanical equipment in spite of the compact structure and narrow space.

Influences on torque measurement in nacelle test benches and their effect on the measurement uncertainty and consequences of a torque calibration

Torque measurement in the MN·m range is important in nacelle test benches, as it constitutes the primary value for the efficiency determination of wind turbine drive trains. However, no traceable measurement is possible above 1.1 MN·m. At the moment, alternatives to direct torque measurement in the MN·m range are, therefore, used. Several of these torque measurement methods are presented and discussed in this paper with respect to traceability and measurement uncertainty. It was found that these methods cannot fully substitute direct measurements. Therefore, detailed recommendations for a torque calibration procedure based on the specific conditions in nacelle test benches (such as rotation and additional mechanical loads) are given so as to enable the traceability of torque measurement using a torque transfer standard.

Soft measurement model on torque of alternating current electrical dynamometer including copper loss and iron loss

Alternating current electrical dynamometer is a common device to measure the torque of engines, such as the gasoline engine. In order to solve the problems such as high cost, high energy consumption and complicated measurement system which exists in the direct measurement on the torque of alternating current electrical dynamometer, copper loss and iron loss are taken as two key factors and a soft-sensing model on the torque of alternating current electrical dynamometer is established using the fuzzy least square support vector machine (FLS-SVM). Then, the FLS-SVM parameters such as penalty factor and kernel parameter are optimized by adaptive genetic algorithm, torque soft-sensing is investigated in the alternating current electrical dynamometer, as well as the energy feedback efficiency and energy consumption during the measurement phase of a gasoline engine loading continual test is obtained. The results show that the minimum soft-sensing error of torque is about 0.0018, and it fluctuates within a range from −0.3 to 0.3 N-m. FLS-SVM soft-sensing method can increase by 1.6% power generation feedback compared with direct measurement, and it can save 500 kJ fuel consumption in the gasoline engine loading continual test. Therefore, the estimation accuracy of the soft measurement model on the torque of alternating current electrical dynamometer including copper loss and iron loss is high and this indirect measurement method can be feasible to reduce production cost of the alternating current electrical dynamometer and energy consumption during the torque measurement phase of a gasoline engine, replacing the direct method of torque measurement.

Experimental investigation of torque measurement in hermetic compressor

In order to measure the compressor torque accurately and guide the design efficiently, a torque measurement method for the hermetic compressor is proposed. Then the shaft power measuring system is established by using a virtual instrument developed by LabVIEW. The stability of slip ring is monitored in real time through an external static full bridge circuit for eliminating the influence of its unstable contact resistance on measurement during the working process. The experimental results indicate that the change of contact resistance cannot be neglected in measuring process. The experimental torque curve is in agreement with the theoretical one. The measured shaft power of the prototype is 320W, finally the motor efficiency and the mechanical efficiency is 91.7% and 89.1%, respectively.

The state-of-art and prospect of contactless torque measurement methods

Torsional vibration is an important factor in the transmission process of mechanical shaft. The torque is also a part of the important parameters for working state of the mechanical shaft. In recent years, research on the measurement method of contactless torque of mechanical transmission shaft has been studied by many scholars. The contactless torque measurement methods have been continuously improved to achieve high precision and high reliability.The methods of contactless torque measurement is presented. The advantages of contactless torque measurement methods are introduced. The development of contactless torque measurement methods in the industry is discussed. Finally, the prospect of contactless torque measurement methods is prospected.

A novel torque sensor based on the angle of magnetization vector

Torque is an important parameter of a mechanical power system, which reflects transmission efficiency, transmission reliability, and operating conditions of equipment. Torque monitoring is very important for real-time control and fault diagnosis of mechanical equipment. A torque measurement method based on the theory of magnetic effect is proposed for multipoint torque monitoring in shafting. A model of the deflection angle of the magnetization vector and torque is established based on the theory of magnetic equivalent. A non-contact signal extraction circuit based on hall sensor is designed, a torque loading experimental device is set up, and the torque calibration experiment is completed. The experimental results show that the sensitivity of the torque measurement system is 17.7 mV/Nm, and the maximum nonlinear error is 0.77% full scale. The deflection angle of the magnetization vector has a good linear relation with the torque, which can be measured indirectly by the deflection angle. This method has the advantages of a simple device, strong anti-interference ability, and non-contact measurement. Because it is not necessary to do special treatment to the elastic shaft, it is convenient to form a non-contact torque sensing node, which can realize real-time monitoring of multipoint torque of shafting.

A study of mechanical torque measurement on the wind turbine drive train—ways and feasibilities

AbstractThe signal of the drive train mechanical torque can be a very informative input for new technologies on the wind turbine, helping further reducing the cost of energy. However, measuring the mechanical torque is not an easy task even during a test campaign on a prototype. In case of the long‐term measurement for operational purpose of use on the turbine, it is often considered as technically and economically not feasible. This paper discusses possible ways of the torque measurement and presents a test campaign where two different methods of torque measurement are conducted. One of the methods measures the shear strain signal using strain gauges at one section of the turbine main shaft. The other method measures the torsional deformation between two positions of the drive train, with an incremental encoder measuring the angular position of the drive train at each position. The tests are conducted on an 8‐MW wind turbine drive train under tests on the nacelle test bench “DyNaLab” of Fraunhofer IWES. During the tests, different load steps of torque and other load components are applied to the drive train. The measurement results from both measuring methods are presented and analysed. In the end, technical and economical feasibilities are discussed for both methods of torque measurement; some suggestions are also given respectively.