Shaft Load Research Articles

Open-Source Data Logger System for Real-Time Monitoring and Fault Detection in Bench Testing

This paper presents the design and development of a proof of concept (PoC) open-source data logger system for wireless data acquisition via Wi-Fi aimed at bench testing and fault detection in combustion and electric engines. The system integrates multiple sensors, including accelerometers, microphones, thermocouples, and gas sensors, to monitor critical parameters, such as vibration, sound, temperature, and CO2 levels. These measurements are crucial for detecting anomalies in engine performance, such as ignition and combustion faults. For combustion engines, temperature sensors detect operational anomalies, including diesel engines operating beyond the normal range of 80 °C to 95 °C and gasoline engines between 90 °C and 110 °C. These readings help identify failures in cooling systems, thermostat valves, or potential coolant leaks. Acoustic sensors identify abnormal noises indicative of issues such as belt misalignment, valve knocking, timing irregularities, or loose parts. Vibration sensors detect displacement issues caused by engine mount failures, cracks in the engine block, or defects in pistons and valves. These sensors can work synergistically with acoustic sensors to enhance fault detection. Additionally, CO2 and organic compound sensors monitor fuel combustion efficiency and detect failures in the exhaust system. For electric motors, temperature sensors help identify anomalies, such as overloads, bearing problems, or excessive shaft load. Acoustic sensors diagnose coil issues, phase imbalances, bearing defects, and faults in chain or belt systems. Vibration sensors detect shaft and bearing problems, inadequate motor mounting, or overload conditions. The collected data are processed and analyzed to improve engine performance, contributing to reduced greenhouse gas (GHG) emissions and enhanced energy efficiency. This PoC system leverages open-source technology to provide a cost-effective and versatile solution for both research and practical applications. Initial laboratory tests validate its feasibility for real-time data acquisition and highlight its potential for creating datasets to support advanced diagnostic algorithms. Future work will focus on enhancing telemetry capabilities, improving Wi-Fi and cloud integration, and developing machine learning-based diagnostic methodologies for combustion and electric engines.

Compensation Algorithm for Wind Turbine Main Shaft Loads Based on LSTM

Abstract For wind turbine development, load size is the core and critical factor. Currently, most companies employ Bladed software for load calculations, which enjoys widespread use in engineering applications due to its efficiency and ease of use. However, constrained by the limitations of blade element theory and momentum theory, there still exist discrepancies between the simulation results and actual conditions. This paper aims to combine simulation algorithms with the application of an LSTM (Long Short-Term Memory) neural network to develop a compensation algorithm for the main shaft loads of wind turbines. By doing so, it endeavors to realize real-time monitoring of the main shaft loads, thereby providing a foundation for achieving high-precision control in wind turbine systems.

The Design and the Control Principle of a Direct Low-Speed PMSM Servo-Drive Operating under a Sign-Changing Load on the Shaft

The paper relates to the development of an algorithm applicable for maintaining the rotational speed of low-speed drives using PMSM motors and operating under a sign-changing load. The moment of inertia of rotating parts does not play the role of a mechanical stabilizer for the speeds discussed in the article. Simulation studies are presented with the aim of developing a rotational speed control algorithm that utilizes only positional feedback and the previously assumed sign-changing load on the shaft. For the purposes of this research, a mathematical model was developed to calculate transient processes in a PMSM machine operating in the conditions of a sign-changing load on the shaft. This model assumes a deterministic control principle adapted to the known nature of the load change. In this model, the mutual influence occurring between the phase fluxes, the electromagnetic torque, the electric currents and the rotor position angle are established on the basis of FEM analysis of a two-dimensional magnetic field using a quasi-stationary approximation. Principles applicable for controlling a direct low-speed servo drive based on a PMSM machine operating with a known variable shaft load using only positional feedback and a predetermined shaft load change law are defined. The proposed regulation method is verified in an experimental manner. For this purpose, an experimental setup was built, which includes a PMSM with a load imitator on a variable sign shaft, an inverter providing sine-shaped power supply to the machine and a digital dual-processor control system. The discussed rotational speed stabilization algorithm was implemented in the form of a program for a microcontroller, which forms a part of the control system. The results of experimental tests confirm the adequacy of mathematical modeling and the effectiveness of the proposed rotational speed stabilization algorithm.

A π-Theorem-Based Advanced Scaling Methodology for Similarity Assessment of Marine Shafting Systems

This paper introduces a rigorous and comprehensive approach to the assessment of marine shafting systems through the utilization of an advanced π-Theorem-based scaling methodology. Integrating journal-bearing similarity assessment and shaft-line scaling methodology with advanced dimensional analysis, the study aims to provide a methodology foundation for systematic replication and analysis of marine shafting systems through scaled models. The proposed scaling methodology ensures geometric and mechanical similarity in terms of shaft-line deflection, considering key scaling parameters such as shaft length, diameter, weight, loads, rotational speed, material properties, bearing locations, and offsets. The advanced dimensional analysis computes specific non-dimensional ratios to guarantee a close resemblance between a real-size system and a scaled lab model. The methodology is analytically derived and validated with numerical simulations for a case study, conducting comparative analysis, evaluating discrepancies, and utilizing the integrated framework for experimentation.

Assessment of the Correlation between the Monitored Operating Parameters and Bearing Life in the Milling Head of a CNC Computer Numerical Control Machining Center

The present paper describes a study conducted at the request of the operator of machining center equipment. The operator observed undesirable indicators in terms of increased backlash and vibration of the milling head and poor quality of the machined surfaces. Vibration measurements and vibrodiagnostics were carried out before disassembling the milling head in the idle state. The bearings, lubricant, and friction regime were analyzed in the next step. The vibrodiagnostic methods used included VEL, ACC, EN2, EN3, and EN4, with recommended limits conforming to STN ISO 10816-3. The vibration values obtained indicated a problem with the bearings, exceeding the limit values. After disassembly of the bearings, abrasive wear, corrosion, and improper lubricant conditions were detected. Lubricant analysis showed the presence of abrasive and corrosive particles, indicating an unsatisfactory friction regime. Determining the optimum lubricant temperature and the effect on friction torque constituted other aspects of the study. Inspection of the bearing microgeometry confirmed unsatisfactory roundness. Furthermore, the assembly of tapered roller bearings with axial preload was analyzed with a focus on bearing stiffness, accuracy, and life. The results showed that preload improves shaft guidance accuracy and load distribution, promoting reliable operation and extending bearing life.

Coefficient of power of Indonesian traditional wind-pump blade model

Indonesia has wind energy potential as a renewable energy resource which is currently being developed intensively. Salt farmers have used it with wind-pump as part of the traditional salt-making process. They have the ability to manufacture, operate and maintain the Indonesian traditional wind-pump. The aim of the experiment was to find out characteristic of windmill of the traditional wind-pump. The characteristics was expressed with relation of coefficient of power (Cp) and the tip speed ratio (tsr). The ratio of the wind mill model was 1: 2.5. The wind mill model consisted of four blades and 80 cm diameter. The experiment was done in a wind tunnel with wind speed of 5 m/s. The adjustable shaft load was electric machine. In the experiment, the wind speed range was 5.7 up to 6.3 m/s and shaft speed was 42.3 up to 387.4 rpm. The experiment resulted minimum and maximum tsr and Cp were 0.295 up to 2.705 and 2.623 up to 11.073, respectively. The experiment found out relationship of Cp and tsr in an equation Cp = -3.248 tsr2 + 12.29 tsr – 1.007. The equation showed that the traditional windmill model has maximum Cp of 10.62 at the tsr of 1.89.

Testing of Electric Drive with a Serial Connection of the Same Phases of Two Induction Motors through Computer Simulation

Objective - check the functionality of the circuit of an electric locomotive fan drive that is not speed-controlled, containing two induction motors, the same stator phases of which are connected in series. Methods: computer simulation of electric drive at rated voltage and under-voltage at different values of shaft load and not equal parameters of motors. The simulation results are presented. Results: the simulation showed that, despite the possibility of sustainable operation at rated voltage, this scheme at under-voltage supply is unstable. Conclusion: the auxiliary electric drive circuit with a series connection of the phases of two induction motors is not recommended for use.

Neural Networks Detect Inter-Turn Short Circuit Faults Using Inverter Switching Statistics for a Closed-Loop Controlled Motor Drive

Early detection of an inter-turn short circuit fault (ISCF) can reduce repair costs and downtime of an electrical machine. In an induction machine (IM) driven by an inverter with a model predictive control (MPC) algorithm, the controller outputs are influenced by a fault due to the fault-controller interaction. Based on this observation, this study developed neural network models using inverter switching statistics to detect the ISCF of an IM. The method was non-invasive, and it did not require any additional sensors. In the fault detection task, an area under receiver operating characteristics curve value of 0.9950 (95% Confidence IntervaI: 0.9949 - 0.9951) was obtained. At the rated operating conditions, the neural network model detected and located an ISCF of 2-turns (out of 104 turns per phase) under 0.1 seconds, a speedup of more than two times compared to the thresholding-based method. Moreover, we published the switching vector data collected at various load torque and shaft speed values for healthy and faulty states of the IM, becoming the first publicly available ISCF detection dataset. Together with the dataset, we provided performance baselines for three main neural network architectures, namely, multi-layer perceptron, convolutional neural network, and recurrent neural network.

Switching backdrivability of a planetary gear by vibration: design parameter setting and excited force estimation

Switching backdrivability according to use status is important to attain energy-saving and compliance in co-worker robots. Authors have proposed switching backdrivability by exciting gear surface, eliminating the need for sensors while switching. We have confirmed that exciting 2K-H planetary gear can switch its backdrivability. To systematically design the switching backdrivable 2K-H planetary gear, this study reveals less back-drive condition and the required torque for a vibrator. In the less-backdrivable condition, the tooth number difference between the fixed and output gears is dominant. Furthermore, the required torque for the vibrator increases as the load of the output shaft and the vibration frequency increase. The experimental results of the less-backdrivable condition and the required torque for the vibrator are almost entirely consistent with simulation result of the mechanical model

Numerical Investigation of the Propulsive Efficiency of a Containership under Load Variation

The International Towing Tank Conference (ITTC) suggests that determining the variations of propulsion efficiency can be achieved by model tests that may be costly and inefficient. This is the reason why this paper investigates the variation of propulsion factors under various ship loading conditions by computational fluid dynamics (CFD). This study proposed a non-iterative method for load variation tests that reduced the computational time. The CFD software Star-CCM+ was used to solve the transient free-surface Reynolds-averaged Navier–Stokes equations. To further reduce the computational time, the propeller was modeled using the actuator disk method. The resistance augmentation, wake fraction, and propeller efficiency of a container ship model KCS with propeller KP505 were studied. These values were used to calculate the load variation coefficient of the shaft revolution speed ζN and load variation coefficient of the delivered power ζP at full scale. The results showed that as the resistance increased, the rotation rate correspondingly increased to maintain the service speed. As the ship resistance increased, the hull and open water efficiencies decreased, and when the actuator disk model assumed a relative rotative efficiency of 1.0, the quasi-propulsion efficiency also decreased.

Identification of Mechanical Parameters in Flexible Drive Systems Using Hybrid Particle Swarm Optimization Based on the Quasi-Newton Method

This study presents hybrid particle swarm optimization with quasi-Newton (HPSO-QN), a hybrid optimization method for accurately identifying mechanical parameters in two-mass model (2MM) systems. These systems are commonly used to model and control high-performance electric drive systems with elastic joints, which are prevalent in modern industrial production. The proposed method combines the global exploration capabilities of particle swarm optimization (PSO) with the local exploitation abilities of the quasi-Newton (QN) method to precisely estimate the motor and load inertias, shaft stiffness, and friction coefficients of the 2MM system. By integrating these two optimization techniques, the HPSO-QN method exhibits superior accuracy and performance compared to standard PSO algorithms. Experimental validation using a 2MM system demonstrates the effectiveness of the proposed method in accurately identifying and improving the mechanical parameters of these complex systems. The HPSO-QN method offers significant implications for enhancing the modeling, performance, and stability of 2MM systems and can be extended to other systems with flexible shafts and couplings. This study contributes to the development of accurate and effective parameter identification methods for complex systems, emphasizing the crucial role of precise parameter estimation in achieving optimal control performance and stability.

An investigation into the micro-geometric tapered-shape surface design of the piston bore of a piston–cylinder interface in an axial piston motor

Abstract. In pursuit of design solutions that reduce energy loss and improve wear resistance for the piston–cylinder interface in an axial piston motor, a fluid-structure interaction numerical model and a new test rig of the friction force of the piston–cylinder pair are developed to achieve the analysis and design of the micro-geometric tapered-shape surface of a piston bore. The piston bore with the tapered-shape surface axial distribution length ratio of 49.44 % of the overall length is found to be the relatively optimized one. Furthermore, how the shaft speed, load pressure, and swash plate angle influence the performance of the two-type interface is analyzed. Numerical analysis results show that, compared with the traditional cylindrical piston bore design, the piston–cylinder interface with the optimized tapered-shape piston bore in the axial piston motor can achieve a significant reduction in leakage flow and friction force, and the experimental results are consistent with the simulation results.

Diagnostics of Transmission Bearing Units Based on Thermal Load Study

Abstract. The operating temperature of the transmission unit is noted to affect its reliability and can serve as a diagnostic criterion. It is proposed to diagnose the transmission unit technical condition by the temperature in the friction zone in order to take into account the influence of air temperature, solar radiation heating and adjacent heat-producing objects. (Research purpose) To ensure the bearing unit controllability based on the thermal load study. (Materials and methods) The study uses the results of calculating the nominal and operational load of the rear power take-off shaft of the Belarus-82.1 tractor. The study uses the three-dimensional modeling and finite element analysis of the temperature distribution under steady-state thermal conductivity conditions. To establish the functional relationship between the temperature in the friction zone and the diagnostic temperature, the method of finite element analysis is used under steady-state thermal conductivity conditions. (Results and discussion) The maximum load modes and temperatures in the friction zone were determined for the 60310A bearing of the power take-off shaft gearbox during aggregation with different agricultural machines such as 4300 Newtons and 2.4 degrees Celsius for FS-2.0U garden cutter (540 revolutions per minute); 4126 Newtons and 40.7 degrees Celsius for Rovatti T3K80/90/2 (540 revolutions per minute) irrigation pump; 956 Newtons and 13.0 degrees Celsius for ROU-6 (1000) manure spreader; 2615 Newtons and 36.6 degrees Celsius for KPRN-3.0A (1000) mower-conditioner. The maximum temperatures as a diagnostic criterion are established in the friction zone, which equal to 41.7 degrees Celsius at 540 revolutions per minute engine speed and 31 degrees Celsius at 1000 revolutions per minute. (Conclusions) Since the direct measurement of the temperature in the friction zone is hardly possible without changing the bearings design, it is proposed to measure the diagnostic temperature on the unit used for mounting the temperature sensor. The coefficient of proportionality k=0.53 of the finite element model is determined. In order to implement diagnostics in an automatic mode, an algorithm is developed for a digital transmission malfunction recorder. Its design is based on the ATmega328 programmable microcontroller and TMP36 temperature sensors. It is found that the digital transmission malfunction recorder provides automatic control of up to seven different transmission units simultaneously, taking into account the ambient temperature.

The effect of laser surface textures on the adhesion strength and corrosion protection of organic coatings - Experimental assessment using the pull-off test and the shaft load blister test

Adhesion is necessary for an effective corrosion protection of metallic surfaces through organic coatings. Even the best anticorrosive coatings fail if it is not well adhered to the substrate. Laser surface texturing (LST) process has been widely used for enhancing adhesion between coatings and steel surfaces in various applications. In addition, recent researches have proven that LST is an effective option for pretreatment of steel surfaces prior to organic coating deposition. This work reports an investigation on the adhesion strength of organic coatings deposited onto AISI-A36 carbon steel laser-textured surfaces. Nanosecond LST via the direct laser writing (DLW) method was used to fabricate V-shaped grooves on the steel surfaces. The distance between consecutive grooves was varied to obtain different surface topographies with controlled surface textured area (TA) ranging from 10 % to 60 %. Conventional bead-blasted surfaces were used as a reference. Surface morphology and topography were characterized through roughness and tortuosity. The frequently used pull-off test (ISO 4624) and a shaft load blister test (SLBT) were used to determine the adhesion of the epoxy coating. In addition, accelerated corrosion tests were carried out to assess the effects of the laser textured surface conditions on the corrosion propagation. After running the pull-off test, all the surfaces' conditions exceeded the minimum pull-off strength value of 5 MPa stated in ISO 12944-9. The results for the SLBT showed that the adhesive strength is highly influenced by the laser-textured area. The geometrical aspects of the groove structure promote phenomena such as mechanical interlock and mechanical hooking of the coating, which affect the adhesion failure mechanism of the organic coating during the test. For lower TA, the crack propagation occurs mainly at the coating/steel interface. However, increasing the TA shows that the crack propagation is stopped near the V-shaped grooves due to the complex shape and must deviate inside the coating for further propagation. Finally, adhesion strength results were correlated with coating delamination rates and an indirect relationship was found.

Mechanical Response Analysis for an Active–Passive Pile Adjacent to Surcharge Load

Due to the complexity of pile–soil interaction, there is little research on active–passive piles that bear the pile-top load transmitted from the superstructure and the pile shaft load caused by the lateral soil movement around the pile simultaneously. The purpose of this study is to analyze the displacement and internal force of active–passive piles. Most of the pile design codes in China use the elastic resistance method to describe the relationship between the lateral soil resistance and the horizontal displacement of the pile, but this is not accurate enough to analyze the internal force and deformation of the pile when the pile displacement is large. For this case, the passive load on the pile shaft caused by the adjacent surcharge load can be described in stages, and the p–y curve method can be used to express the relationship between the lateral soil resistance and the horizontal displacement of the pile. Additionally, taking both the active load (vertical force, horizontal force, and bending moment on the pile top) and the passive load into account, the deflection differential equation of the pile shaft is herein established, and a corresponding finite difference method program is implemented to obtain the calculations pursuant to the equation. The correctness of the analysis method and program was verified by two test cases. The results show that our calculation method can effectively judge the flow state of the soil around piles and accurately reflect the nonlinear characteristics of pile-soil interaction. Moreover, the influence depth of the pile displacement under the passive pile condition caused by the adjacent load is significantly greater than that under active pile condition, and the maximum pile-bending moment appears near the interface of soft and hard soil layer.

Analysis of Point Contact Isothermal Elastohydrodynamic Lubrication Characteristics of a New Type of Trigeminal Universal Coupling for Automobile

This thesis designed a new type of trigeminal universal coupling structure that changes the original surface contact sliding friction into point contact rolling friction. We analyzed the characteristics of isothermal elastohydrodynamic lubrication to ensure new construction on the drive shaft stability, reliability, and durability. First, we established a contact model of the improved new structure and analyzed the isothermal elastohydrodynamic characteristics of the point contact. Then we studied the input shaft frequency, load, deflection angle, and lubrication characteristics. Research indicated that the other being equal, the faster the input shaft frequency could lead to a thicker oil film, a higher oil film pressure, and a higher secondary pressure peak. The higher load could cause the thinner oil film thickness, the lower oil film pressure, the later position where the pressure begins to increase, and the less obvious second pressure peak. The greater deflection angle could bring about the thicker oil film thickness, the higher oil film pressure, the earlier position where the pressure began to increase, and the earlier position at which the secondary pressure peak was located. This phenomenon was more pronounced in the contact center area.

Study of contact load on cycloid wheel of RV reducer based on MATLAB

This paper analyses the working principle of RV reducer and the actual tooth profile equation of cycloid wheel, and deduces the distribution law of contact load on cycloid wheel in transient state by considering the initial meshing gap between pin teeth and cycloid wheel and the contact deformation generated during meshing. Taking an RV reducer as the research object, the contact load of the cycloid wheel is calculated by using MATLAB programming, and the change curve of contact load and crank shaft rotation angle is obtained, which provides theoretical support for the analysis and design of RV reducer.

Improvements to and Experimental Validation of PI Controllers Using a Reference Bias Control Algorithm for Wind Turbines

In this study, a reference bias control (RBC) algorithm for variable speed and variable pitch wind turbines was designed and validated. To improve the performance of conventional PI control algorithms, the RBC algorithm applies biased references to power and pitch angle to the pitch and the torque control loops, respectively. To validate the control performance of the improved RBC algorithm, hardware in the loop simulator (HILS) was conducted using a commercial programmable logic controller (PLC). The performance of a conventional PI control algorithm and the proposed RBC algorithm were compared for the target wind turbine model in terms of both the transition region and the rated power region. In the transition region, the proposed RBC algorithm improved the sudden dips in the generator torque and power, which often occur when using a control algorithm with a switching logic. As a result, the damage equivalent load (DEL) of the main shaft was reduced by 15%. In the rated power region, the rotor speed deviation was reduced by 22% and the power deviation was reduced by 21%. To experimentally validate the control performance and applicability of the RBC algorithm, wind tunnel testing using a wind turbine scaled model was additionally performed. Similarly to the HILS testing result, it was confirmed that the DEL of the main shaft and fluctuation of the rotor speed and power decreased with the proposed RBC algorithm.

Real-Time Investigation of Temperature Effect on Induction Motor Equivalent Circuit Parameter Change

Today’s developing technology and increasing demands in production areas continue the importance of studies on induction motors (IMs). To meet the demands, the mathematical modeling of IMs must be performed fully and accurately. Variable conditions cause changes in many electrical, magnetic, and thermal parameters. A change in parameters affects the intensity, efficiency of the operating currents of the machine, thereby changing the motor losses. In this article, the objective is to determine the changes in the equivalent circuit parameters of three-phase squirrel-cage induction motors (SCIMs) with different powers under the variable conditions (stator winding temperature, load, and motor shaft speed). Supervisory control and data acquisition (SCADA) program read real-time information (temperature, current, voltage, power, shaft speed, and torque) from the experiments and necessary calculations were made. When the test results were examined, a maximum of 9 % change was observed in the motor ECPs (RS, R2, RM, XS, X2, and XM) at different shaft speeds as a result of the change in the stator winding temperature between 100 % and 110 %. At different loads, this rate of change increases to 16 %. This has shown that motor shaft speed and load, together with temperature, have a significant effect on the ECPs.

Research on indirect measurement and estimation method of shearer drum cutting load

For the difficult problem that the shearer drum load is difficult to be detected and perceived directly, a shearer drum load indirect estimation measurement method and technique is proposed and invented. Based on the structural characteristics of the rocker arm, the basic rod system skeleton of the rocker arm is extracted. Based on the transfer route of the drum load on the rocker arm, the feasibility of using the rocker arm pin shaft load for drum load prediction is analyzed, and the correlation mechanics equation of load from the drum to the rocker arm pin shaft is constructed. To address the statically indeterminate problem in the equation, the Lagrange multiplier is introduced to construct the energy function of the rocker rod system skeleton. Based on the principle of minimum complementary energy and solving the extreme value of energy function, the statically indeterminate equation is transformed into the statically determinate equation, and a rough prediction model of drum load based on the force of the rocker arm hinged ear pin shaft is derived, and the maximum relative error of the model is 25.15 %. To address the low prediction accuracy of the model due to the dynamic characteristics of the drum rocker arm, the drum load is derived from the rocker arm hinged ear pin shaft load and the rough prediction model as input, and the experimentally measured drum load as output. The bp neural network error correction model is constructed, and the accurate estimation and perception of the drum load are realized by the prediction model and the bp neural network correction model. Finally, the accuracy of the prediction algorithm is verified by experiments. The results show that after correction by bp neural network, the average error of the drum three directional force is 0.14 × 104N ∼ 0.55 × 104N, the mean square error is 0.18 × 104N ∼ 0.65 × 104N, and the relative error is 3.99 %∼10.12 %. The average error of the drum three directional moment is 0.31 × 104N·m ∼ 0.40 × 104N·m, the mean square error is 0.16 × 104N·m ∼ 0.50 × 104N·m, and the relative error is 2.04 %∼11.44 %. The accuracy of drum load prediction is higher than 11.44 % in all cases. The research results can provide theoretical and technical support for intelligent shearer design, development, and healthy operation and maintenance.