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Having great performance on active power regulation, grid-connected adjustable-speed pumped storage unit (ASPSU) has attracted world-wide concern. This superior transient response is achieved by both its excitation system and speed governing system, but dynamic characteristics study of ASPSU taking into account the optimal control of speed governor has seldom been explored. This paper first presents small-signal-stability model of on-grid ASPSU. Furthermore, instead of the dynamic-performance-indexes rule, a stability-degree criteria is proposed to optimize parameters for the speed regulator of ASPSU, which aims at improving the dynamic behavior of rotational speed and guide vane opening. Firstly, a mathematical model of on-grid ASPSU with power priority control is derived and it is validated by comparing simulated performance with on-site measurements of a Japanese commissioned ASPSU. Secondly, the small-signal-stability model is showcased, and the influence of control parameters on the stability degree which builds the bridge between eigenvalues and transient performance is investigated in details. Thirdly, instead of improved integral of time-weighted-absolute-error criteria, a novel stability-degree criteria is utilised in particle swarm optimization algorithm to optimise the regulator’s parameters of ASPSU. Finally, with the optimised parameters, the indicial response of a 400MW on-grid ASPSU built with PSCAD/EMTDC is significantly enhanced.

The feasibility of aerial fertilization by UAV-based granular fertilizer spreaders (GFSs) has been widely accepted. Although commercial UAV-based spreaders have emerged, their performance in granular fertilizer spreading application has rarely been studied. This paper tested the performances of four existing UAV-based GFSs in the automatic controllability, range of the discharge rate and the swath width and uniformity of the distribution. An analytic hierarchy process (AHP)-based method was proposed to evaluate their comprehensive performance in spreading application. The main results are as follows: (a) GFS-A showed the maximum controllable discharge rate of 27 kg/min, and GFS-B showed the minimum (proximately 3 kg/min). The discharge rate could be changed in a stepless way by GFS-B, C and D. The relationship between the discharge rate and the rotational speed of the fluted roller of GFS-D showed a significant linear relationship ( $\text {R}^{2} = 0.9991$ ) for the operational range. (b) The distribution patterns of GFS-A and D were trapezoidal, which was the better deposition pattern for generating uniform spreading; those of the other two UAV-based GFSs were a wide triangle with obviously asymmetrical sides (GFS-B) and a typical M-shape with two peaks (GFS-C). (c) the simulation of CV-swath width illustrated that the available effective swath width (CV ≤ 20%) for these UAV-GFSs were 5.1m (CV = 14.73%), 4.8m(CV = 17.55%), 3.9m(CV = 13.02%) and 5.7m(CV = 18.36%) respectively under the given conditions. Furthermore, according to the AHP-based evaluation model, it was proved that GFS-D was able to provide superior performance in precise fertilization for a large application range, which is important for its practical application. This comparative study makes useful contribution for farmers and researchers in this field in understanding the application performance of various UAV-based GFSs.

To improve the safety of superhighways, a virtual track system for superhighways based on intelligent road buttons is studied by means of a structural analysis and mathematical model. The system consists of a road subsystem, onboard subsystem and service center subsystem. When a vehicle equipped with an onboard subsystem nears the road buttons, they activate the virtual track system, and the reader reads location coordinates and road alignment information at that point from the label buttons. At the same time, the data processing module begins to function. First, the module reads the linear parameters and processes them to obtain the angle between the road tangent and vehicle body. Then, the module reads the angle of the front wheels, the vehicle speed and the distance between the adjacent two label buttons. Finally, the module obtains the rotational speed of the steering wheel while the vehicle is driving between two label buttons by using the computational model and sends the control parameters to the steering motor. The research results show that when the design speed of the superhighway is 140 km/h, 160 km/h and 180 km/h and the distances between the road buttons are less than 1.33 m, 1.50 m and 1.69 m, respectively, the distance between the centerline of the road and the vehicle can be restricted to less than 50 cm. Therefore, the virtual track system based on intelligent road buttons can restrict vehicles to travel in the virtual track and ensure the safety of superhighways.

Aluminum alloys have low weldability by conventional fusion welding processes. Friction stir welding (FSW) is a promising alternative to traditional fusion welding techniques for producing high quality aluminum joints. The quality of the welded joints is highly dependent on the process parameters used during welding. In this research, a new approach was developed to predict the process parameters and mechanical properties of AA6061-T6 aluminium alloy joints in terms of ultimate tensile strength (UTS). A new hybrid artificial neural network (ANN) approach has been proposed in which Henry Gas Solubility Optimization (HGSO) algorithm has been incorporated to improve the performance of Random Vector Functional Link (RVFL) network. The HGSO-RVFL model was constructed with four parameters; rotational speed, welding speed, tilt angle, and pin profile. The validity of the model was tested, and it was demonstrated that the HGSO-RVFL model is a powerful technique for predicting the UTS of friction stir welded (FSWD) joints. In addition, the effects of process parameters on UTS of welded joints were discussed, where a significant agreement was observed between experimental results and predicted results which indicates the high performance of the model developed to predict the appropriate welding parameters that achieve optimal UTS.

Although the pure electric drive system is widely applied to mobile machines, it is not easy for construction machinery (CM) to realize electrification because of the different working style. The CM load changes dramatically and continuously, and the traditional PI control cannot handle this condition. A vector control strategy based on speed sliding mode control (SMC) and torque PI control is proposed for CM with the characteristic of drastically changing loads. Based on the mathematical model of an electric motor-pump, the electric motor-pump control performance requirement for electric CM is analyzed. Combined with the permanent magnet synchronous motor (PMSM) mathematical model, the speed SMC-PI observer is designed. The controller is designed using an exponential approximation method and uses integral and differential links, which has excellent robustness, to suppress flutter in SMC-PI. Control strategies of speed loops with PI and SMC-PI were compared under different conditions. The overshoot of the motor-pump speed was small and zero static control could be achieved. When the load was variable, the fluctuation of rotation speed was approximately 0.5%~1% with SMC-PI, which is only 25%~50% of PI control. Finally, the vector control algorithm based on speed SMC-PI was tested on a hydraulic excavator driven by the electric motor. The test results show that the vector control base on speed SMC-PI achieved a maximum static difference of rotational speed of approximately 1%. When the load power was close to 50% of the rated power, the electric motor-pump speed fluctuation range was -5%~5%, and the steady-state error was only approximately 0.3%.

In order to solve the problems of low magnetic field utilization rate and low volume-torque ratio of the traditional magnetorheological (MR) brake under a volume constraint, a rotary MR brake with multiple fluid flow channels was proposed. The magnetic flux was guided into the external axial fluid flow channel by inserting a non-magnetic ring in the middle of the magnetic conduction sleeves which could improve the magnetic circuit structure greatly, the working area where the MR brake producing rheological effect was increased, and the effective damping gaps were also increased from two sections to four sections. The working principle of rotary MR brake was expounded and torque mathematical model was also deduced. The electromagnetic field was modeled and the distribution of magnetic flux density in multiple fluid flow channels was analyzed using finite element method. The prototypes of initial and optimal design were fabricated by using the obtained optimal geometric parameters. An experimental test system was setup to investigate the dynamic performance of the proposed rotary MR brake. The experimental results show that the maximum braking torque and torque ratio of the optimal MR brake are increased by 13.5% and 2.3% compared with the initial MR brake at the applied current of 1.8 A, respectively. At the same time, the variation trend of experimental and simulation results is basically consistent, and the rotational speed has almost no effect on the torque performance, which is conducive to the application of MR brakes under different working conditions.

The qualities of functional parts produced by underwater friction stir welding (UWFSW) with additive water are significantly reliant on standard FSW process parameters. To improve the goal function, hybrid statistical tools can be used to optimize operation parameters. This work investigates the tensile strength(σUTS) of tests ASTM D638-14 specified parts manufactured using UWFSW by Al AA 6063-T6 material. Three parameters were varied in the fabrication of test specimens: speed of rotation from 1000 to 1800 rpm, speed of traveling from 4 to 10 mm/s, and shoulder diameter from 10 to 20 mm. Using a Hybrid artificial neural network- genetic algorithm (ANN-GA) and Hybrid artificial neural network-fuzzy-genetic algorithm (ANFIS-GA). The ANFIS-GA achieved the highest precision of 98.99 %, resulting in optimum parameters like rotational speed 1800 rpm, travelling speed 4 mm/s, and shoulder diameter 15 mm to produce a maximum tensile strength of 266 MPa. The hybrid models developed could be used to predict and maximize specific process parameters and impacts for a variety of industrial situations.

The power losses in high power-density motors due to high rotational speed and/or high pole counts may be reduced adopting metal amorphous nanocomposites (MANCs) featuring low power loss and a relatively high flux density ($\sim$1.3 T). We recently proposed a flux switching permanent magnet (FSPM) motor with a rating of 2.5 kW at 1400 Hz electrical speed that incorporates low loss (

This paper verifies the proposed methodology of a novel Dual-mode Reluctance Motor which can switch the motor mode between a switched reluctance motor and a synchronous reluctance motor to enhance the high efficiency region. Theoretically, the iron loss of a synchronous reluctance motor mode is low with respect to that of a switched reluctance motor mode in higher rotational speed and low power region because of the lower iron loss specification of the synchronous reluctance motor. In this paper, the current waveforms of both the switched reluctance motor mode and the synchronous reluctance motor mode are realized, then, the motor specification can be switched. Also, the test results of the DRM are carried out at the low speed and low torque region is carried out to check the variation of the motor specification.

This paper investigates a bearingless motor with full passive suspension. The axial direction is stabilized by an electrodynamic force generated by a specific coil configuration called a figure-eight coil. Radial directions and tilting angles are stabilized by passive permanent magnet bearings. Since the electrodynamic force increases with rotational speed, it must overcome a certain minimum threshold speed to compensate the rotor weight and the unstable axial force caused by the permanent magnet bearing. A weight relief structure with a pair of permanent magnets in attractive configuration is designed to reduce the axial load by the rotor weight. This weight relief structure reduces the balance axial position at steady state. With a smaller axial displacement, the suspension current, and, consequently, the copper losses at rated operation are reduced. An external inductor is connected in series with the coils, resulting in enhanced electrodynamic stiffness at low rotational speed. Through theoretical equations derived in a previously published manuscript, an appropriate external inductor is chosen. Forces in the radial permanent magnet bearings and weight relief structures are calculated through Finite Element Analysis. The steady state balance position and the minimum rotational speed required for full passive suspension are estimated through the theoretical equation. It is found that both the external inductance and the weight relief structure improve the axial stiffness performance for rotational speeds below 5000 rpm.

This paper describes the possibility of control and regulating the electromagnetic torque of the eddy current brakes (ECBs) with permanent magnets (PMs). This achieved by dividing conducting disc rotor on several parts that are connected by springs. Because of interaction between centrifugal forces and spring forces, the rotor parts can take a place in working air gap where the PMs create magnetic field. Since centrifugal forces are determined by the rotational speed, self-regulation of the brake torque is realized. The paper presents the results of simulation of a magnetic field and a method for assessing the electromagnetic moment.

Gyroscope with lasers implementation is an important field of study with great potential. An integrating rate gyroscope is called a laser gyroscope (LG). The interference occurs in the form of a lock-in zone (LZ) during the operation of the LG, which leads to insensitivity at low rotation speeds, e.g. a ship, a submarine, where the speed is less than the threshold. In this case, the LG is practically useless in the rotational speed determination. The impact of dithering on the LZ was investigated by modeling the LG operation equation and a measuring stand that reduces the effect of the LZ at low angular velocities was developed.

A new design scheme of photo-electrical rotary joint dynamic detection device is proposed, which can simulate the actual working state of photo-electrical rotary joint and dynamically detect its photo-electrical performance at its actual working speed. According to the scheme, a kind of watertight photo-electrical rotary joint detection device is designed. The optical signal insertion loss, contact resistance, life of the watertight opto-electrical rotary joint and other parameters can be tested under variable rotation speed and high voltage.

This work is devoted to the study of the energy characteristics of a vehicle electric drive. A stand has been developed makes it possible to measure the electrical power consumed by a variable-frequency drive, while varying the rotational speed of the motor shaft and the torque generated by it. On the ground of the data obtained using the stand, a family of curves was constructed that describe the dependence of the efficiency on the torque at a fixed rotating frequency. The analysis of the obtained dependencies showed the presence of maxima, which provide a basis for finding the minimum energy consumption during acceleration by varying the gearbox ratio.

The paper proposes a model of the electromechanical control system for the sucker-rod oil pumping unit with the feedback based on the pump filling factor. The structural diagram of the system is presented and its operation algorithm is described. The control system relies on a Hamming network, which determines the level of marginal well filling by recognizing the recorded load curve and generates a control signal. The optimal operation mode for the oil pumping unit is established by setting the rotation speed of the driving motor in accordance with the flow rate of the formation. The simulation of the normal and emergency modes of the oil pumping unit was implemented based on the experimental data.

This paper investigates the potential of two types of locally resonant metamaterials to damp out the vibrations of flexible rotating rings. First, a classical solution using tuned vibration absorbers with only one radial mode is investigated. For this solution, the resulting stopband is largely independent of the rotation speed. Next, tuned vibration absorbers with both radial and tangential modes are investigated. The presence of both modes allows the gyroscopic effect to split the stopband and potentially leading to a better vibration reduction.

This paper presents preliminary results of estimating the rotational speed of a helicopter rotor, using the short-time Fourier transform (STFT) and its concentrated form referred to as horizontal synchrosqueezing (HS) in the time-frequency (TF) domain. The presented theory is supported by real-life data obtained using a small, high-resolution radar system during a measurement campaign. The outcomes illustrated in the paper show a pronounced potential of using TF techniques in the analysis of micro-Doppler radar signals and extracting additional content from target parameters that can be used in classification and parametrization procedures. The paper shows that using the concentrated version of the spectrogram, one can distinguish more details in a non-cooperative target than the classical STFT, which in the presented research was used for assessing target parameters.

In this paper, a three-dimensional beam model of the blade is presented, which may help to determine the frequency of the main mode of vibration under centrifugal load, characterized by the highest level of vibration stresses of the two-blade H-type Darrieus rotor. The dependences of the natural frequencies and the decrement of the blade vibrations on the rotational speed of the wind turbine rotor are obtained. The approaches presented in the paper to the modelling of the computational model of the blade in an integral Fourier transform frequency domain allow us to take into account the arbitrary dependence of energy dissipation on the frequency of vibrations under the action of centrifugal load.

Large-size diesel engines used in power generators, locomotives and ships require the use of turbochargers in order to provide them with optimal operating point. These turbochargers often work under very hard conditions - high temperatures, vibrations, aggressive exhaust gases - causing component wear and demanding periodic service. The blades and bearing elements are the most sensitive parts. The operating conditions, especially overloading and excessive speed, are often responsible for the premature failure of the device. Failure to notice early signs of degradation and the approaching need for service may lead to a serious damage. Some turbocharger units use devices that monitor the environmental and operating conditions, e.g. rotational speed. However, these are complex and hence costly systems. This article presents a compact device designed to be installed on a turbocharger, equipped with a number of environmental sensors, such as pressure, humidity, temperature, and interfaces to connect further external sensors. The most important feature of the device is that it is equipped with a set of built-in accelerometers for the analysis of vibrations, and for estimating the rotational speed without the use of a dedicated rotational speed sensor. The device can be equipped with bluetooth low energy wireless connectivity and internal non-volatile memory for data collection. On-board processing power helps to compute and interpret the results. Thanks to this, it is possible to determine normal and abnormal working conditions of the turbocharger, its overloads, overheating or excessive system pressure. This data, regularly collected, is very useful for predictive maintenance.

The paper considers a complete magnetic suspension of a small-sized horizontal rotor in passive radial and active axial magnetic bearings. It describes experimental studies of the dynamics of a model rotor in a combined passive-active magnetic suspension. The studies were performed using the developed specialized software and hardware complex for measuring and analyzing the dynamic characteristics of rotors with magnetic suspension systems. Its software includes special algorithms of the mathematical data processing for measuring and evaluating the main parameters of the signals characterizing the vibration displacement of the rotor points. The results are presented in the form of vibrograms of rotor support section motion in the radial direction, spectrograms of these signals and amplitude-frequency characteristics. The work shows how the proposed experimental analysis of the vibration state of a rotor system with magnetic bearings allows modifying the rotor design to reduce the vibration amplitudes at rotation speed values close to the critical ones.

This paper establishes a supercharger turbo wheel reliability accelerated degradation model which is based on neural network nonlinear fitting. First of all, by the analysis of 120 hours supercharger structure test and 350 hours engine whole machine reliability test, the limit of durability of the material is determined as degradation degree and temperature and rotational speed are determined as sensitive stresses. Then, according to the method of neural network nonlinear fitting, the K418 material durable performance data are supplemented. Furthermore, from the above information, we propose two turbine wheel reliability accelerated degradation models, which include 120 hours supercharger structure test model and 350 hours engine whole machine reliability test model. Finally, the method of turbo wheel residual lasting life assessment is proposed with the help of the proposed models, and a conclusion that the 120 hours structural assessment test of the supercharger meets the 350 hours whole machine reliability assessment test is obtained.

Application of process intensification technique in chemical-based synthesis processes has been a growing trend. In this regard, Spinning Disk Reactors (SDR) have attracted considerable attention due to their enhanced heat and mass transfer properties. Moreover, equipment’s inherent simplicity in changing the process parameters is considered to provide the user with the flexibility in fine tuning the nature and quality of products formed. In this study the effect on the particle size due to the changing rotational speed of the disk is discussed in relevance to the synthesis of Precipitated Calcium Carbonate (PCC) nanostructures. Hence, PCC has been synthesized in a locally fabricated SDR with a 15 cm diameter disk at different disk rotation speeds. The potential of the equipment to reduce particle size and further synthesize PCC nanostructures is identified. The obtained results are discussed in comparison to chemical kinetic data of previous studies.

This paper presents the development of a model for thin slab caster mould cooling water pumping station. This station is responsible for initiating product's solidification in the mould, resulting in a strong steel shell to be formed around the mould's inner periphery. In a continuous process, motor driven rolls pull the shell out of the mould through a “roller apron”, where the secondary cooling system completes the solidification of the product's liquid core. This model includes three parallel centrifugal pumps, where each one is coupled to a three-phase induction motor and connected to a cooling water application running under flow control strategy. Each pump is driven with a variable frequency drive that utilizes frequency control method for adjusting the rotational speed, in order to match system operational point with the consumption point for saving energy. MATLAB/SIMULINK software, utilizing SIMSCAPE library and variable step size, simulates this model. The model's validation is done through comparing the simulation's results in different operating conditions with the actual behavior of the system.

Accelerated thermal aging of synthetic ester fluid is carried at 120°C and their subsequent variation in charging tendency and dielectric properties with oil and pressboard were studied. Spinning disc system simulates the electrification phenomenon in laboratory conditions. The Flow electrification process is simulated with three configurations as, virgin oil with pressboard, aged oil with pressboard and aged pressboard with the fresh oil. The generation of current magnitude increases with the rotational speed of disc and with temperature. In addition, drastic reduction is observed with aged specimen. Surface potential measurement in pressboard is performed with +/-DC voltage profiles. Higher accumulation of charge and relatively lower charge decay performance is exhibited by aged specimens. In addition, Dielectric relaxation spectroscopy (DRS) studies exhibits the dielectric characterization of oil, the aged specimen is found to have a higher loss factor. Dielectric parameters are responsible for the electrification at the interface of the medium.

Regarding the imaging of circular scan inverse synthetic aperture radar (ISAR), the rapid circular scan of the antenna expands the beam coverage area. However, how to determine the rotation speed of the antenna is still a difficult problem. This paper proposes an antenna speed optimization model to quantify the antenna rotation speed. Under the constraints of the beam coverage area per second and the accumulated signal-to-noise ratio (SNR), the value of azimuth resolution is minimized. In addition, to improve the resolution of the image, the split Bregman algorithm is also introduced. This algorithm solves the problem that the azimuth resolution is still lower than the traditional ISAR after the antenna rotation speed is optimized. By optimizing the antenna rotation speed and processing data by the split Bregman algorithm, a super-resolution ISAR image is obtained. The simulation results verify the effectiveness of the method.

This paper presents six design alternatives of permanent magnet synchronous generator for low-speed wind turbines. The design approach followed is an iterative process, based on the results of finite element analysis (FEA). For this purpose, two software were used which are ANSYS electronics, and Motor-CAD. This paper targets two configurations, which are surface mounted magnets and interior magnets. The design procedure starts with the stator and rotor design, then winding configuration design, and finally axial length optimization. This was done while maintaining high generator’s performance. The final design achieved, on one hand, high air gap flux density values (around 1.2 T). On the other hand, the terminal voltage level varied between 97 V and 224 V depending on the axial length (at constant rotational speed of 400 rpm).

To satisfy the requirements of transmission mechanisms with variable transmission ratio, the curve face gear mechanism of compound motion has been proposed, which can build variable transmission ratio and rotation/movement compound motion simultaneously with fewer components and more compact structure. The transmission equation was established and the anti-floating design of the pinion was presented. Combined with critical floating conditions, the relationship among engagement state, rotation speed, stiffness and some other parameters have been shown obviously. According to the discrete method, the difference of meshing tooth pair in a half cycle was set up and converted as the equivalent model with time-varying properties. The dynamic response equations of this gear pair were obtained and the influence of parameters on response displacements were analyzed. Compared with the experimental results, the correctness and rationality of the theory was verified, laying a theoretical foundation for the following research and application of this gear pair.

Skull drilling is an important and difficult process in neurosurgical craniotomy, which will inevitably produce a lot of heat. Correct understanding of the heat production law of skull drilling has important guiding significance for craniotomy robot. In this study, cortical bone and cancellous bone were layered to establish models according to the 3D reconstruction data of skull. The finite element method based on ABAQUS is used to establish the skull drilling model and realize the simulation of bone tissue surgical instrument interaction state for surgical robot. The results show that when the drill rotation speed and feed speed increase, the drilling temperature will also increase, but the drill rotation speed will have a more significant effect on bone drilling temperature, and when the drill rotation speed is low (300r/min, 600r/min), the drill bit diameter has little effect on the drilling temperature, but when the drill rotation speed is higher (900r/min, 1200r/min), the larger diameter drill bit(11mm) will produce more drilling heat.

The interplay of diffraction and self-focussing nonlinearity in an optical cavity results in the formation of spatial Turing patterns. Using helically-phased pumps, the patterns form on rings and rotate. We show how fully-structured light can be used to gain precise control over the rotation speed.

We propose a numerical model of magnetic brake design with viscose ferrofluid as controllable friction material. Friction damping force is controlled by an electric coil, where the current value is regulated depending on the rotational speed of the device. Results about friction force and total braking force/torque are obtained by coupled finite element method modeling and electromagnetic brake kinematical model. Effects of the viscose ferrofluid over the breaking force and torque are estimated.

In order to Gatling gun's main roller shaft, it shows by using the force analysis. It shows the rotation speed of the main roller shaft is non-constant, it can be determined by the cam curve and the clearance fit between the main roller and the cam curve. The speed of the revolution and position of the main roller shaft was raised and dropped in the core hole. The main roller shaft is sometimes integrated with the bolt movement, but basically, it makes that the main roller only deforms itself, so the main roller shaft is a method for the Gatling cannon. The Gatling cannon needs the main roller shaft more than the Gatling gun. In Gatling cannon, the main roller shaft must be sure to exist. The main roller shaft and bolt body should be two components, not one component. This is the caliber greater than 20mm scheme, and not for the caliber less than 20mm design.

In the nuclear field, in areas with high-end radioactivity, the instrumentation devices (sensors and transducers) are affected over time by the destructive effects of radiation and fail relatively quickly. To avoid these problems, it is usually avoided to introduce sensors in the radiation field, so to obtain precise control functions of stepper motors, limited or optimized control in their open loop is used. The paper analyzes and maps the areas where the stepper motor has a low position error, based on the behavior in variable load and influenced by the parameters voltage and rotational speed. To achieve this we statistically process a high volume of data that characterizes stepper motor. A limitation of the rotation speed can temporarily solve the problems of angular displacement, an elegant solution is the optimization of the displacement functions according to the characteristics of the electromechanical system. In order to optimize the functions of the fast travel and micro-stepping functions, in this paper are statistically analyzed data sets that contain the parameters of the stepper motor for the two functions using well-known software tools such as R programming and Matlab. The statistical processing of the parameters aims at influencing and obtaining an optimal confidence interval and a minimization of the error for the positioning functions of the stepper motor used in nuclear applications with high gamma radiation field.

The measurement of propeller speed of a quadrotor helicopter is very useful to estimate its thrust force. The infrared light on the optoelectronics method is used to detect the existence of the propeller by non-contact technique for avoiding friction and loss. The phototransistor is applied as a sensor then the data signal is processed by voltage comparator and microcontroller. The objective of this research is to investigate the rotation speed of propeller measurement quadrotor helicopter by optoelectronic of non-contact technique. The measurement results indicated that the propeller rotation increased non-linearly to the time. Therefore, the speed of the propeller fluctuates dramatically, which may be caused by noise and disturbance of sensor, counting error of microcontroller also the non-linearity characteristic of DC motor as the rotor. The measurement uncertainty tends to be larger at a higher speed. Because of these circumstances, many data samples are required to estimate the actual value of propeller speed measurement exactly. In addition, these nonlinearities should be taken into account to control thrust force for hovering properly the quadrotor helicopter.

The paper considers the problem of exciting a rotating spherical cavity by an azimuthal frame of an electric current. The frequency response of the field inside the cavity is constructed. The effects of splitting the fundamental resonator frequency at rest into new frequencies are analyzed. The possibility of monitoring and measuring the rotational speed using this effect is indicated.

The aerodynamic properties of propellers strictly depend on their geometry. Pitch is one of the key parameters defining propeller performance. This paper presents the results of a wind-tunnel investigation of the propellers for the unmanned aerial vehicle. In this paper, the performance of a set of 12-inch propellers with different pitch values for different values of air velocity was analyzed. The tests were performed on a specially designed test stand placed in a wind tunnel test chamber. The test stand enabled adjustment of the air velocity as well as the propeller rotational speed. An adequately selected set of sensors allowed to record the defined parameters. Obtained results allowed to evaluate the performance of the considered propellers with different pitch values in forced airflow conditions.

The choice of propeller geometry in the electric propulsion of an aircraft has a significant impact on its performance. There are few studies devoted to the experimental testing of propellers dedicated to this type of propulsion. This paper presents the results of an experimental study of the propellers for the electric propulsion system. Selected parameters related to the performance of a set of 12-inch plastic propellers with different pitch values were analyzed in the study. The tests were carried out on a constructed test stand which enabled the adjustment of parameters such as rotational speed or voltage of the electric motor. The test stand was equipped with a set of sensors that allow the recording of defined parameters. The obtained results give general knowledge about the performance of the propellers with different pitch values under static conditions and constitute the basis for further research under forced airflow conditions.

Mechanical hands with closed-loop control and haptic functions are in great need in recent years due to their merits such as satisfactory user experience, accurate grasp operation and etc. However, the high financial cost of these smart systems strongly limits the broad use of these smart systems. To address this issue, we designed a low-cost mechanical hand with haptic functionality. Experimental results demonstrate an average delay time of 11.8ms of the feedback system, and 1 kg of the maximum loading, and an average finger rotational speed of 155°/s, which illustrate that this design has met the common standard of similar products. The total cost of this system is only $1.7k, indicating its affordability for broad users.

This paper presents a novel micro electret power generator as self-powered railway sensor for both horizontal oscillation detection and rotation speed monitoring. Both the electret material and counter electrode are micro-patterned with square-shaped blocks and connected diagonally. By this way, capacitance variation can be maximized in either horizontal oscillation or axial rotation. From the experiment results, they show obvious differences between the waveforms from two types of motions. Therefore, both the rotation of the iron wheel and the change of the track in railway can be precisely detected and distinguished. The experimental results show that the peak value of the output voltage can reach 121.94 V when the rotation speed is 600 rpm in the rotating mode and 132.96 V in the sliding mode. The self-powered sensing system can not only achieve stable and continuous output signals, but also adapt to the multi-directional working environment. The outcomes of this work offer new insights of realizing single structured electret power generator for multifunctional applications.

Current industries that use high-speed rotation systems are starting to replace the standard mechanical bearing systems with magnetic suspension systems. This tendency to replace mechanical bearings is due to the advantages of magnetic bearings, for instance low losses, high reliability lubrication free operation and the ability to work in vacuum Magnetic bearings can allow the suspension of a rotor without any mechanical contact in rotating machinery which can produce a high rotating speed and position precision, thus removing the problems introduced by mechanical bearings such as low dynamic stability, thermal lock, and limited rotation speed This paper deals with design procedures for two different topologies of active magnetic bearings (AMBs) that might be applied for a high-speed machinery. The virtual prototypes of the magnetic bearings are created and simulated, and a comparative analysis of magnetic bearings is performed.

Studying motor faults and their behavior first requires simulating a healthy squirrel cage induction motor, which is achieved when the output values and the target values are similar. In initial experimental results, the output values did not reach target values. The three target values are stator nominal current, nominal torque, and nominal rotational speed per minute (rpm) on the nameplate of the actual motor. Therefore, the goal of this research was to determine the optimum values for the six input parameters that contribute to the minimum difference between the output and target values. This was conducted using MATLAB SIMULINK and evaluated using the Grey relational analysis. Two simulated motors are used to optimize inputs for getting output values that are very closed to the target values. The output values of the simulated motor were almost identical (98.5-99%) to the values of targets on the nameplate data on the actual motor in the laboratory. Therefore, the output values of the simulated motor allow us to study motor faults experimentally. Another result is that a new equation was developed during this research work.

This paper is about the study, calculation, and simulate the speeds of each leg of the three-leg pipe inspection robot. Wall Pressing Three-plane pipe inspection robot is a very popular type of pipe inspection robot. Such a robot will have a steering ability utilizing three identical motors that are connected to each of the three wheels of the robot by a mechanical means. The issue that needs to be considered here is the movement of the robot when passing through different kinds of pipe shapes (ex. Elbow) or different kinds of Joints (ex. T-section). The three-plane pipe inspection robot depends on wall pressing as attraction force so slipping inside the pipe is unacceptable. That means the speed of each leg relating to the other two legs has to be correctly calculated otherwise the robot will suffer a disorder movement inside the pipe. The paper will address the issue of calculating differences between the speed of each leg and how much it is important to synchronize the rotational speed of all motors when they change their speed in the presence of variable disturbances in torques. To maintain a correct speed when facing disturbances, the PID controller will be introduced as a solution. The PID should be tuned in regards to the properties of the selected motors and the input torques as they change through the movement. The robot will be designed to inspect 508mm pipes so all the equipment will be chosen according to that. The simulation of MATLAB will show a satisfying result when simulating the motor response that is enhanced by the use of the PID through the various cases.

The article discusses the possibility of using a frequency converter for mechanisms that require several speeds of rotation, both fixed and with the possibility of smooth change. A developed frequency converter with vector-algorithmic control is proposed and the result of mathematical modeling of the proposed frequency converter in comparison with a direct-acting motor in the MATLAB Simulink environment is presented. This frequency inverter adopts a simple control system that can be executed in various ways to adjust the rotational speed of a three-phase induction motor. In addition, a physical model of a frequency converter with vector-algorithmic control was developed and assembled, and a comparison of the physical and mathematical models was made.

In the last decades, the renewables market is focused on distributed grids and solutions suitable for private use in households. A low-speed wind turbine based on the Magnus effect is one of the promising technologies in that area. By its construction, for the power management, Magnus effect-based wind turbine requires additional motors to control the rotational speed of the blades. An integrated motor-drive system for Unmanned Autonomous Vehicles (UAVs) matching the requirements in terms of weight, size, rotational speed, and controllability. In this case study, an application of the permanent magnet synchronous motor (PMSM) designed for UAVs in a Magnus effect-based wind turbine prototype is presented. The control system design methodology is presented, and the performance of the system is experimentally evaluated.

This paper deals with the stress analysis of various shapes of flywheel energy storage systems in conjunction with the double u-core switched reluctance machine. The inquiry is proposed according to the key factors in a flywheel layout including cost, material strength, energy storage capacity, mass and size of flywheel. The purpose of the study is to present a cost-effective flywheel with high efficiency of energy storage, in the absence of any expensive material and complex design. To this end, the analytical results of the tolerable rotational speed and its related amount of stored energy in an aluminum disk flywheel using double u-core switched reluctance machine as its driver has been first obtained. After ensuring the accuracy of the model by comparing the analytical results with those of numerical 3D CAD Workbench, different shapes of flywheel have been scrutinized to present a desired design for the flywheel to operate with high speed double u-core switched reluctance machine. In this investigation, the minimization of energy storage system cost and maximization of the stored energy are considered as the objectives. Moreover, the moment of inertia of the flywheel structure and the tolerable speed of the applied material used in the construction for preventing any failure are defined as the constraints.

This paper presents a study of an improved switching methods with an AC-DC converter and a combined control technique with Pulse Amplitude Modulation and Pulse Width Modulation for the Surface Permanent Magnet Synchronous Motor drive. An improved six step control and high frequency injection synchronized with rotation speed can eliminate the harmonic current noise.

The dynamic analysis of a vibrating rotor-stator rubbing in an inviscid fluid is studied in this experimentally paper. The unbalanced rotor system is widely used in rotordynamic, and unbalance-rubs coupling fault is essential and can occur simultaneously. An experiment is conducted on an RK4 rotor test rig partially submerged in a non-viscid fluid medium to extract and analyse its vibration characteristics. The dynamic responses under variable parameters such as rotational speed ratio, the initial clearance, mass eccentricity, and inter-shaft stiffness on the rotor system's dynamic behaviours are investigated. The model parameters' effects revealed a fractional frequency multiplication component and abnormal rotor trajectory due to the nonlinear rub-contact in both air and fluid medium through the experimental test. The Wavelet Synchrosqueezing Spectrum provides additional information to understand the influence of the fluid during the rotor-stator contact. Therefore, the proposed Synchrosqueezing method has proven to be effective in extracting and studying the characteristics of rubbing faults in a rotor-bearing system. The analysis result of the experiment shown a qualitative similarity with the obtained numerical results.