Optimization of Three-Phase Hybrid Stepper Motors for Noise Reduction

For the optimization of three-phase hybrid stepper motors with complex electromagnetic structures, an optimization method is presented in this paper. The method is a combination of 3D-FEM and the Taguchi optimization method intended to reduce the dependence on FEM results during the optimization calculation. In this paper, the optimization method is used in the optimization of the tooth shape of the three-phase hybrid stepper motor, and the objective is to reduce the noise caused by harmonics in the “torque-angle characteristic” of the motor. It is clear that traditional optimization methods make it very difficult to carry out such an optimization calculation as a large number of finite element calculations have to be used in the optimization process, and the required computation time is extremely long. Using the optimization method presented in the paper, the optimization becomes feasible because the number of finite element calculations is greatly reduced and the computation time is thus greatly reduced. In order to check the effectiveness of the optimization, the waterfall diagram for noise analysis and its application to check torque ripple are also presented in the paper. Both simulation and test results show that the optimized structure can significantly reduce the motor noise caused by torque ripple. Therefore, the optimization method proposed in this paper can be an effective tool for the optimal design of high-performance motors, including stepper motors.

Drying Machines with Combined Hydrodynamic Regimes

The article is devoted to the study of multistage dryers with vertical sectioning of the working space. The factors of influence of the design of the shelf contact and the consumption of the drying agent on the mode of movement of monodisperse and polydisperse material are analyzed. The achievement of the required hydrodynamic regime (at a constant consumption of the drying agent) was ensured by changing the length of the shelf contact, the angle of its inclination to the horizon, and the degree of perforation (free area of cross-section). The features of changing the mode of granular material movement at various stages of the gravitational shelf dryer are shown. A technique for the optimization calculation of a gravitational shelf dryer is proposed. As an objective function, the minimum residence time of the dispersed material in the dryer is taken, at which the required amount of moisture is removed. Variants of the designs of the stages of a gravitational shelf dryer are shown and the features of the movement of dispersed material on the steps are described. The results obtained can be used as the basis for the engineering design of gravitational shelf dryers.

Multi-objective optimization for control parameters of underwater gliders considering effect of uncertain input errors

In actual application, the energy utilization rate of underwater glider directly affects the total voyage range. When underwater glider is used for executing exploration mission for a fixed point, the position that the glider resurfaces should be accurate enough. In this paper, we employ a multi-objective optimization method to determine the control parameters values that can maximize the position accuracy that the glider resurfaces and the energy utilization rate simultaneously. Especially, the optimization of this paper considers the effect of uncertain input errors. The control parameters include the net buoyancy adjustment amount and the movable mass block translation amount. The input errors include the control parameters errors, the motion depth error and the current. Based on the dynamic model of an underwater glider, we propose the calculation model and evaluation flow that are used for analyzing the glider position accuracy and energy utilization rate, considering the effect of uncertain input errors. Besides, a combinatorial experimental design method is proposed to calculate the performance evaluation parameters under different control parameters values. Then the radial basis function neural network is employed to establish the surrogate models of performance evaluation parameters to participate in the optimization calculation, which can improve the optimization efficiency. After optimization calculation based on the non-dominated sorting genetic algorithm II, we obtain a Pareto optimal set consisting of 257 sets of non-dominated solutions. Finally, the selection rule of optimal control parameters values is given, and the optimization results are validated under 3 sets of solutions. This research may be valuable for the improvement of the glider work quality.

Fast error calibration of Flexible Measuring Arm based on an adaptive Genetic Algorithm

With the development of measurement technology, the Flexible Measuring Arm (FMA) is widely used in quality test of automobile processing and industrial production. FMA is a kind of nonlinear system with many parameters. Low cost and efficient calibration method have become the focuses of attention. This article presents a fast calibration method for FMA based on an adaptive Genetic Algorithm (GA) just with several standard balls and a ball plate. It can greatly reduce the calibration cost than common external calibration method which needs high precision instruments and sensors. Firstly, the kinematic model of FMA is established by RPY theory. Secondly, the common GA is optimized and improved, and an adaptive mechanism is added to the algorithms which can realize the automatic adjustment of crossover and mutation operators. A Normalized Genetic Algorithm (NGA) with adaptive mechanism is proposed to complete the optimization calculation. It can improve the numbers of optimal individuals and the convergence speed. So, the search efficiency will be enhanced greatly. Finally, the Least square method (LSM), the General Genetic Algorithm (GGA), and the proposed NGA are respectively used to finish the calibration work. The compensation accuracy and the search efficiency with the above three different algorithms have been systematically analyzed. Experiment indicates that the performance of NGA is much better than LSM and GGA. The data also has proved that the LSM is suitable to complete optimization calculation for linear system. Its convergence stability is much poorer than NGA and GGA because of the ill-condition Jacobin matrix. GGA is easy to fall into local optimization because of the fixed operators. The proposed NGA obviously owns fast convergence speed, high accuracy and better stability than GGA. The position error is reduced from 3.17 to 0.5 mm after compensation with the proposed NGA. Its convergence rate is almost two time of GGA which applies constant genetic factors. The effectiveness and feasibility of proposed method are verified by experiment.

TO CALCULATION OF THE OPTIMAL DEGREE OF DAMAGE TO A BUILDING BY SEISMIC IMPACT

Дана постановка задачи по расчету оптимальной степени поврждения здания при сейсмическом воздействии. Условие оптимизационного расчета записано в виде вероятностно-экономической целевой функции, где начальные затраты на антисейсмическое усиление здания уравновешиваются с вероятностыми потерями, связанными с наступлением той или иной степени повреждения здания. Вероятность безотказности здания, соответствующая данному уравновешенному состоянию, названа оптимальной надежностью, а степень повреждения - оптимальной степенью повреждения. Всего в соответствии со шкалой MSK-64 рассмотрены 5 степеней повреждения. Последовательности переходов из одних состояний повреждения в другие представлены в виде простейшего Марковского потока с непрерывным временем и дискретными состояниями. Составлены дифференциальные уравнения процесса переходов и представлены их общие решения. В случае если последствия наступленияопределенной степени повреждения здания носят как экономический, так и неэкономическией характер, предложено, исходя из зависимости расчета экономических потерь и затрат от повышения надежности до высоких уровней и показателя нормативного уровня надежности здания, определенного по предлагаемому в литературе выражению, принять решения о допустимой степени повреждения здания. The problem statement is given for calculating the optimal degree of damage to a building under seismic impact. The condition of the optimization calculation is written in the form of a probabilistic-economic objective function, where the initial costs for antiseismic strengthening of the building are balanced with the probabilistic losses associated with the onset of one or another degree of damage to the building. The probability of a building's reliability, corresponding to a given balanced state, is called the optimal reliability, and the degree of damage is called the optimal degree of damage. In total, in accordance with the MSK-64 scale, 5 degrees of damage are considered. Sequences of transitions from one damage state to another are presented in the form of the simplest Markov flow with continuous time and discrete states. Differential equations of the transition process are compiled and their general solutions are presented. If the consequences of the onset of a certain degree of damage to the building are both economic and non-economic in nature, it is proposed, based on the dependence of the calculation of economic losses and costs from increasing reliability to high levels and the indicator of the standard level of building reliability, determined according to the expression proposed in the literature, to make decisions on permissible degree of damage to the building.

Perencanaan Perhitungan AKNOP Pada Daerah Irigasi Mrican Sebagai Upaya Peningkatan Kinerja Irigasi

Food security is one of the targets of the Sustainable Development Goals that must be achieved by 2030. One of the problems faced in achieving this target is the decrease in the function of irrigation infrastructure by ± 70%, resulting in the reduced water supply to agricultural land. The purpose of this research is to recalculate the operational and maintenance needs of the Mrican Irrigation Area by the applicable regulations and the current conditions of the study area for the needs of the 2021 budget year.The research was conducted in the Mrican Irrigation Area with an area of ​​30,341 ha located in 3 districts, namely Kediri, Nganjuk and, Jombang. The result of optimization calculation of personnel for operational activities and maintenance of irrigation networks in the Mrican Irrigation Area is 577 people. The length of the carrier line is 366 km and the drainage is 248 km long. The number of waterworks as many as 966 units. The results of calculations and analyzes that have been carried out, it is found that the amount of the Operational and Maintenance Real Needs of Mrican Irrigation Area for the irrigation operational management component is Rp. 6,329,767,232, the component of surface irrigation operation costs Rp. 31,490,208,724, and the maintenance component of the surface irrigation network is Rp. 22,685,844,371. The total cost of the Operational and Maintenance Real Needs of Mrican Irrigation Area is Rp. 60,505,820,327.