Motor Failure Research Articles

A Qualified review of ML and DL algorithms for Bearing Fault Diagnosis

Moving machinery is the backbone of socio-economic development. The use of machines helps in increasing the production of everyday used items, and tools, that generate electricity and mechanical energy, and provides easy and fast transportation and help by saving human efforts, energy, and time. The mechanical industry is totally dependent on the bearing and it is considered bread and butter of the system. Bearing failure is about 40% of the total failures of induction motors which is why it is a crucial challenge to predict the failure and helps prevent future downtime events through maintenance schedules with the latest techniques and tools of. This paper presents a review of how DL techniques and algorithms outsmarted ML for bearing fault detection and diagnosis and summarizes the accuracy results generated by most common DL algorithms over classical ML algorithms. Additionally this paper reasons different criteria for which DL algorithms have been proved efficient for building productive model in the field of bearing fault detection. Furthermore, some of the most famous datasets by different universities have been discussed and accuracy results are provided by reviewing algorithms on the CWRU dataset by different researchers and comparison chart is listed in the results section.

MLC performance prognosis using a degradation model based on trajectory log data from a daily test.

This paper investigates the feasibility of implementing a predictive maintenance program for a multileaf collimator (MLC) based on data collected in trajectory logs (TLs) obtained by conducting a simple daily test, with the aim of minimizing unscheduled downtime. A dynamic field test was designed, and the TLs generated in the course of daily administration in a linear accelerator were collected to evaluate trajectory deviations of the MLC leaves as well as interlocks (COL 420219/20, COL 420207/08) reported by the machine. During this evaluation, we observed that the trajectory deviations of some leaves increased up to a threshold value beyond which certain interlocks began to appear in treatment fields in those leaves. An exponential degradation model was therefore developed to predict this drift and determine each leaf's remaining useful life (RUL). Once the applicability of the model was confirmed, we added a second accelerator equipped with an MLC with the same configuration to validate the model. The model was able to predict certain COL 420219/20 interlocks resulting from primary readout/expected position discrepancies and to estimate each leaf's RUL. In total, 11 cases (8 interlocks + 3 potential interlocks avoided due to service interventions [27.3% of the total]) were detected over 7 days in advance, with no false positive results. Scheduling of service interventions several days prior to MLC failure would therefore be possible. When these types of interlocks were not predicted by the model, they were always generated by leaf motor failure. Consequently, intervention time could also be optimized by directly replacing the motor. During the study period, for these types of interlocks, our approach would have reduced downtime from 35.25 to 4.00h (88.7%) and from 34.75 to 22.83h (34.3%) for each accelerator, respectively. For COL 420207/08 interlocks, which are generated by primary/secondary readout discrepancies, no correlation with leaf trajectory deviation increases recorded in the TLs was found. Throughout the study period, these types of interlocks requiring service intervention, also mainly for motor replacement, represented a downtime of 9.50h for the first accelerator (21.2% of total downtime) and by 4.33h (11.1% of total downtime) for the second accelerator. This study demonstrates that by applying a predictive MLC maintenance program based on information collected in TLs, it is possible to predict certain interlocks and therefore schedule preemptive interventions to avoid their occurrence. This could optimize health-care delivery performance and minimize the loss of treatment sessions.

Design, modeling, and simulation of dual-source redundant braking system

Based on the existing theory of EHB braking system, a new dual-source redundant braking system (DSRB) is proposed in this paper. The proposed DSRB is improved on the classic ESP system structure with two sets of motor hydraulic pumps, four throttle valves and two balance valves used to replace the failed oil inlet and outlet valves added in it. Then, the requirements of redundancy, reliability of intelligent vehicle braking system can be met by the system. The wheel cylinder pressure of DSRB system is accurately regulated by PID control algorithm. Finally, the co-simulation based on AMEsim/Simulink were implemented to verify the accuracy and reliability of the braking efficiency of the DSRB. Results show that the designed DSRB has fault tolerance even in the case of partial failure, that is, inlet and outlet valve failure and complete failure, that is, inlet and outlet valve and hydraulic motor failure at the same time. And good braking efficiency, boosting speed and pressure regulation accuracy are still available.

Torque allocation strategy based on economy and stability for electric vehicle considering controllability after motors failure

To reduce the energy consumption and improve the stability of distributed drive electric vehicles, a torque allocation strategy based on an economy and stability optimisation function (ESOF) and a fuzzy proportional-integral-derivative rule control (FPRC) strategy are proposed while considering motor efficiency, braking energy recovery and motor failure. First, the vehicle dynamics and motor equivalent models are established. Subsequently, a torque prediction model and fuzzy controller for the vehicle are designed to calculate the total desired torque and yaw moment, respectively. A torque optimisation function is established to minimise power losses in the electric motor and maximise braking energy recovery, and it is solved using an improved genetic algorithm. While satisfying vehicle driving constraints, the ESOF-based controller can effectively coordinate the operation of each motor in the high-efficiency range under driving and braking conditions. After one motor fault is detected, the ESOF-based controller is replaced with an FPRC-based controller to distribute the vehicle demand torque. A co-simulation platform integrating MATLAB/Simulink and CarSim is developed to verify the effectiveness of the proposed ESOF-based controller in the New European Driving Cycle (NEDC) and Federal Test Procedure 75 (FTP75) driving cycles. The effectiveness of the FPRC-based controller in step steering condition is verified using the co-simulation platform. The simulation results indicate that the vehicle economy and driving range of the ESOF-based controller improved compared with the results afforded by the typical torque distribution strategy based on the front–rear axle dynamic load ratio. The average efficiencies of the motors in the NEDC and FTP75 driving cycles increased by 2.94% and 2.4%, respectively. More importantly, the FPRC-based controller can more significantly improve the steering stability of a vehicle with motor failure compared with the ESOF-based controller.

Increasing reliability of traction electric motors of diesel locomotives taking into account thermophysical parameters of insulation and armature winding conductors

Introduction. The issue of ensuring the operable state of the DC traction motor is relevant due to its large-scale use on diesel locomotives, including modern powerful motors, operating on lines with increased train masses. At present, a rather difficult situation has developed in the locomotive industry with the failure of diesel locomotive traction electric motors due to a decrease in the insulation resistance of the armature windings of the electric motors and their subsequent breakdowns: up to 28 % of the total number of failures of electric motors are due to breakdown of the hull insulation and interturn short circuit of the armature and 13 % of cases are due to reduction in the resistance of the insulating material.Materials and methods. The paper considers the main directions of scientific research on the causes of insulation integrity failure, which lead to unscheduled repairs of traction motors. The theoretical substantiation of the root causes of insulation destruction is based on the importance of taking into account the coefficients of thermal linear expansion of copper and its insulating materials. In order to study thermodynamic processes in the winding of a traction motor, a computational finite element model of a winding coil laid in the groove of the armature core has been developed. The winding model is represented separately by a conductor and insulation, between which contact conditions are specified. The conductor of the calculation model heats up to 120 °C from the current flow. Mathematical apparatus embedded in the MSC calculation program, Patran – Nastran, made it possible to evaluate the deformation of the conductor relative to the insulation as a result of a linear increment due to thermal expansion.Results. With the help of mathematical modelling and based on the results of finite element analysis, the confirmation of the theoretical justification is clearly shown. The difference in elongation during heating of the motor armature conductor and insulation, obtained by mathematical modelling, is 0.6 mm and is significant for the winding (consisting of a conductor and insulation), which is usually considered as a single whole body.Discussion and conclusion. The obtained result shows the need for more detailed studies to select the technology for the insulation of the DC traction motor. The use of insulating materials for the armature winding with coefficients of thermal linear expansion equal to the coefficient of thermal expansion of the copper conductors of the winding will improve the reliability of traction electric motors of diesel locomotives in operation.

Impact of Motor Stator Winding Faults on Motor Differential-mode Impedance and Mode Transformation

Motor impedance and mode transformation have significant effects on the electromagnetic interference (EMI) generated in motor drive systems. Stator winding faults commonly cause motor failure; however, in their early stages, they may not affect the short-term operation of the motor. To date, EMI noise under the influence of premature stator winding faults has not been adequately studied, particularly the differential-mode (DM) noise due to the common-mode (CM)-to-DM transformation. This study investigates and quantifies the influence of stator winding faults on the motor DM impedance and mode transformation. First, the transmission line model of an induction motor is described based on the scattering (S) parameter measurements of each phase of the motor. It offers the flexibility to emulate different types of stator winding faults at specific locations and various severities, such that the impacts of the faults on the motor DM impedance can be easily estimated. Second, a test setup is proposed to quantify the CM-to-DM transformation due to the stator winding faults. The findings of this study reveal that even the early stages of stator winding faults can result in significant changes in the DM noise.

Approach to Predicting Failures of Traction Electric Motors

Approach to Predicting Failures of Traction Electric Motors

The design of a new type coaxial multilayer rotor helicopter vehicle

Today’s small rotor helicopter vehicles mostly use electric motors and batteries as power sources. Most helicopter power configurations are either front powered or rear powered, causing the center of the helicopter to be offset. This kind of offset should be overcome by structural compensation or by adjusting the angle of attack of the blades, but some lift of the angle of attack will be sacrifice at the same time. This paper proposes a new type of electric helicopter powertrain design. The advantage of new type helicopter design is setting the centre of gravity at the centre position of helicopter. The main shaft of the helicopter through the power transmission method of the electric motor built into the internal gear of the star gear, which improves the design of the center offset of the helicopter. That is improved the flight stability of the helicopter. At the same time, in terms of power transmission, the motor power consumed by the primary gear power of the star gear, while the traditional helicopter power transmission method has three or four gear power losses. The new concept of electric motor with star gear structure proposed in this paper can effectively reduce the transmission power loss of the gear. In addition, the distributed power control system proposed in this paper also reduces the possibility of helicopter crash due to motor failure.

Diagnosis of induction motor failures using discrete wavelet transform of an auxiliary winding voltage

Over last years, great attention has been developed to avoid the machines breakdown especially in the squirrel cage induction motor which suffer from different failures. The aim of this paper is to present a new method for the diagnosis of rotor bar breakage and end ring in induction machine fed by an inverter based on discrete wavelet transform applied on the voltage of an auxiliary winding as a new monitoring signature. The expression of the auxiliary winding voltage related to a small coil inserted between two stator phases is presented. The study is focused on the high-level signals of approximation and details coefficients. Thus, the evolution of any frequency of interest in the waveform is given in this paper. The method is validated by simulations of four broken bars and end ring cases under unloaded and loaded machine.

Fault-tolerant motion planning for a hexapod robot with single-leg failure using a foot force control method

Hexapod robots are widely used for resource exploration, post-disaster rescue, and military equipment. They typically travel on rugged and complex roads. The robot itself has a high probability of failure owing to mechanical failure, driving motor failure, or external environmental interference. To improve the adaptability of the robot to a complex environment, a motion control method for fault-tolerant gait was designed. The trajectory generator based on zero-moment point information can generate a smooth desired trajectory for the body’s center of mass, thereby improving the robot’s zero-moment point trajectory tracking effect and motion stability. The force-distribution algorithm based on torque optimization selects the minimum square sum of the driving force as the objective function and reduces the number of constraint equations through QR decomposition to increase the speed at which the expected contact force at the foot is calculated. A CoppeliaSim and MATLAB/Gurobi joint simulation platform were built to simulate and verify the fault-tolerant motion planning of the hexapod robot and foot contact force control algorithm. The feasibility and effectiveness of the fault-tolerant motion planning and foot force control algorithm applied to a hexapod robot with a single-foot failure are verified.

Correlation between solid propellant failure and interface debonding in solid rocket motors

In the traditional integrity analysis of solid rocket motors, solid propellants failure and propellant-liner interface debonding were intentionally differentiated. This empirical distinction of failure regions based on the macroscopic phenomenon neglects their physical correlation, consequently increasing both experiment quantity and simulation complexity. Here, by experiments and simulations, propellant-liner interface debonding is shown to be induced by propellant breakage, i.e., the substrate failure. In experiments, interface debonding and propellants failure share the same cavitation and stringing processes in crack initiation, and the measured break strain of solid propellants and fracture energy of interface satisfy a similar temperature/strain-rate dependent shifting phenomenon. The finite element model can well predict both the strain field and the stress-strain response of interface debonding by using the parameters calibrated by tensile tests of solid propellants, verifying that interface debonding is induced by propellants breakage. Overall, failure envelopes of both propellants and interfaces satisfy a similar peak-position shifting phenomenon but different peak-value shifting phenomena. The time-temperature superposition of HTPB polymer binders induces the peak-position shift, and strain concentration and relaxation of propellants in the crack front induce the peak-value evolution. This study is promising to unify and simplify the solid propellants failure and interface debonding in the integrity analysis.

Simulation of ozone concentrations inside 60CO industrial irradiator

The motivation of this work is to study the relationship between gamma radiation and also ozone concentration in 60CO industrial irradiators. Because ozone is considered to be one of the most important safety issues, because it has a destructive effect on the human body and has a corrosive effect on metal parts in the irradiated area. Moreover, due to its high reactivity. So first using ozone monogram method to measure ozone concentration, and also the effect of the factor on ozone concentration was determined. MATLAB computer code was used to calculate the ozone concentration-response with completely different statistics. Among them, ozone concentration in the 60CO irradiation area is in a completely different state. These conditions include: different gamma emitters, completely different irradiators, airflow correction, and engine failure. It is suggested that ozone formation may be a direct effect of gamma radiations. the result show also that the health hazards due to the ozone produced during irradiation are significant and should not be overlooked. It was observed that in case of 1Ci motor failure, the detection time is 67.5 minutes. While, for 0.1Ci motor failure, the detection time is 32.2 minutes. To fulfill the employee safety limits. it is recommended to have a second control system with ventilation

Electrical Testing for Detection and Classification of Open Damper Bar and Shorted Field Winding Failures in Wound Field Synchronous Motors

Broken damper bars and shorted field winding turns degrade the starting and running performance of industrial wound field synchronous motors (WFSMs), and can lead to a forced outage of the motor and driven process. Testing of WFSM rotor windings mainly relies on offline tests, which cannot be performed frequently and are known to lack reliability. Shorted turns in the field winding can be detected online from the airgap flux measurement, but require a sensor to be installed on the stator bore. In this article, new test methods for detecting and classifying damper and field winding faults based on electrical signals are proposed. The proposed methods can provide remote testing at motor standstill and during the motor starting transient without disassembling the motor. Test results on a 30 kW, salient pole WFSM show that both test methods can provide reliable detection and classification of damper and field winding faults.

Study on Electrical Pitting Prevention Device of a Rotating Shaft Using Automatic Control Potential Balancing.

A rotating body consisting of a rotating shaft and bearings inevitably generates voltage and current. The potential difference between the bearing and the shaft is the main cause of electrical corrosion, which causes motor failure, shortened bearing life, and many safety issues. To prevent corrosion, passive shaft-grounding devices use conductive materials and brushes; however, these devices cannot be completely grounded, so there is a difference in local potential, and brush friction generates a shaft current. The cumulative effect causes electrical corrosion; therefore, in this study, an electrical corrosion protection device for the rotating power supply shaft was developed. It detected current and potential difference and established a feedback system on the rotating shaft. It also energized the rotating shaft using an external power supply to eliminate the potential difference on the shaft and reduce electrical corrosion. The result was prolonged motor life and improved stability, operating efficiency, and operability of related equipment. In this study, a rotating-shaft test rig was set up, and a constant current was applied to simulate the potential difference and verify the performance of the anti-corrosion device. Gradually, the design scheme was optimized; the potential difference on the rotating shaft was accurately quantified; and the goal of controlling the potential difference within 2 mV was achieved. Finally, the electrical corrosion protection device was applied to the rotating shaft of a merchant ship, and the current and potential difference on the rotating shaft were monitored for 30 days. The results showed that the device had excellent performance in reducing the potential difference on the rotating shaft and preventing electrical corrosion.

Fault simulation of medium voltage squirrel cage induction motors

The main objective of this paper is to model failures of squirrel cage rotor induction motors, it presents the equations that model the machine variables, and we simulate an induction motor in the Matlab-Simulink software, to know and evaluate the effects of the stator windings when the motor experiences failure to function as a short circuit between spirals that there are many diagnostic methodologies for each class of failure. The most widely used technique is analyzing the frequency spectrum of one or several motor signals. A fault in the motor represents an asymmetry concerning its construction; consequently, harmonic components appear in the electrical signals that are related to the present fault, and the spectral analysis of motor current signatures applying the fast Fourier transform (FFT) to the current since these contain relevant information that is distinguished in a spectrum of frequencies.

Actuator Fault-Tolerant Control for Four-Wheel-Drive-by-Wire Electric Vehicle

This article presents an active fault-tolerant control (FTC) approach for four-wheel drive-by-wire (4WDW) electric vehicles (EVs) with unmatched disturbance, whose purpose is to preserve stability and improve the tracking performance under actuator fault. The proposed scheme is divided into four steps. First of all, an unmatched nonlinear disturbance observer (NDOB) is established based on the 4WDW EV model to estimate the equal disturbance and compensate for the modeling error. Then, a state tracker with estimated unmatched nonlinear disturbance is designed. Followed by the design of a novel adaptive sliding mode fault-tolerant control (ASM-FTC) strategy based on NDOB. Finally, control efforts allocate according to the degree of motor failure. On the one hand, controller parameters are capable of self-adaptively reconfiguring such that a faster convergence can be realized. On the other hand, better tracking performance is guaranteed with the application of estimated disturbance information in the control law. Hardware-in-the-loop (HIL) simulation results illustrate the validity of the proposed method in various driving scenarios.

DC motor fault detection and isolation scheme with the use of directional residual set

The subject of research is presented as online-estimation of characteristics of DC motors under various loads. The paper is devoted to a modern approach to solve the problem of detecting DC motor failures. Proposed detection method is based on the set of full state Luenberger observers. Isolation scheme uses directional residual set and relationships between fault direction and residual vector. The procedure of synthesizing the fault detection and isolation algorithm for DC motor is designed. This scheme performance is proved with computer modeling of typical DC motor RK 370CA with faults caused by unaccounted force momentum acting on rotor, input voltage disturbance, velocity and current sensors failures. The algorithm correctly defines motor state (fault presence or absence) and also properly isolates fault cause. Proposed method advantage is compared to other solutions based on hardware and timing redundancy, identification and observers lies in the opportunity to detect and isolate faults of input and output signals with trivial synthesis and absence of the need to expand system hardware. Proposed method is applicable to any second order system, and also there is a possibility to use it for higher order systems with the corresponding changing of the equation systems solving for observer synthesis. This algorithm allows realizing online fault isolation and does not require additional measuring which promotes decrease of diagnostic costs, repair and serving time saving, modern accident detection. The results can be applied to DC motor control to increase reliability and to develop DC motor control systems.

Gravity compensation of a 2R1T mechanism with remote center of motion for minimally invasive transnasal surgery applications

AbstractThis work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center of motion. A previously developed balancing solution is modified and applied to a prototype, and test results are presented. The mechanism is an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, the endoscope is inserted through a nostril of the patient through a natural path to the pituitary gland. During the surgery, it is vital for the manipulator to be statically balanced so that in case of a motor failure, the patient is protected against any harmful motion of the endoscope. Additionally, static balancing takes the gravitational load from the actuators and hence facilitates the control of the mechanism. The mechanism is a 2URRR-URR type parallel manipulator with three legs. The payload mass is distributed to the legs on the sides. By using counter-masses for two links of each leg, the center of mass of each leg is lumped on the proximal link which simplifies the problem of balancing of a two degree-of-freedom inverted pendulum. The two proximal links with the lumped mass are statically balanced via springs. Dynamic simulations indicate that when the mechanism is statically balanced, generated actuator torques are reduced by 93.5%. Finally, the balancing solution is implemented on the prototype of the manipulator. The tests indicate that the manipulator is statically balanced within its task space when the actuators are disconnected. When the actuators are connected, the torque requirements decrease by about 37.8% with balancing.

Automatic Speed Control of Motor with Over Current and Thermal Protection

This paper aims to design a controller to minimize the accidents of mechanical failure of industrial generators and motors under heavy load or malfunction. The controlling parameters such as the speed of motor is done via controlling the voltage and current fed to the motor. The speed control can be possible by using PWM technique. The factors which affect the motor can be sense using temperature and current sensor. The system also utilizes Over current & Thermal based backup protection scheme for failure protection.

Güvenli kara sistemi mimari tasarimi motor arizalarini dikkate alarak çok rotorlu mimari tasarimi

There is growing interest to use drones for application like delivery services, air taxi, surveillance, and inspection to reduce operational time and cost and increase the performance and functionalities. However, there are some risks related to using this technology one of them is the hazard to the humans and assets in the case of an emergency scenario like motor failure. The current technologies suggest to land as soon as possible in such these scenarios, however finding and selecting a suitable landing area considering the capabilities of the faulty drone and controlling the drone towards the selected point is a problem which requires provisions during the design process of the drone. The situations get more complex considering that the vehicle should be able to adopt itself by its time varying environment. In this paper the system approach is used to break the safety requirements to functional and physical requirements and based on these requirement analyses, the functional and physical architectures of the drone are designed. The proposed design suggests that the drones aggregate their perception about the environment to maximize the safety of people and assets through a special databank called potential landmark databank.