Optimization of Center of Gravity Position and Anti-Wave Plate Angle of Amphibious Unmanned Vehicle Based on Orthogonal Experimental Method

When the amphibious vehicle navigates in water,the angle of the anti-wave plate and the position of the center of gravity greatly influence the navigation characteristics.In the relevant research on reducing the navigation resistance of amphibious vehicles by adjusting the angle of the anti-wave plate,there is a lack of scientific selection of parameters and reasonable research of simulation results by using mathematical methods,and the influence of the center of gravity position on navigation characteristics is not considered at the same time.To study the influence of the combinations of the angle of the anti-wave plate and the position of the center of gravity on the resistance reduction characteristics,a numerical calculation model of the amphibious unmanned vehicle was established by using the theory of computational fluid dynamics,and the experimental data verified the correctness of the numerical model.Based on this numerical model,the navigation characteristics of the amphibious unmanned vehicle were studied when the center of gravity was located at different positions,and the orthogonal experimental design method was used to optimize the parameters of the angle of the anti-wave plate and the position of the center of gravity.The results show that through the parameter optimization analysis based on the orthogonal experimental method,the combination of the optimal angle of the anti-wave plate and the position of the center of gravity is obtained.And the numerical simulation result of resistance is consistent with the predicted optimal solution.Compared with the maximum navigational resistance,the parameter optimization reduces the navigational resistance of the amphibious unmanned vehicle by 24%.

Application of orthogonal experimental design and Tikhonov regularization method for the identification of parameters in the casting solidification process

The inverse heat conduction method is one of methods to identify the casting simulation parameters. A new inverse method was presented according to the Tikhonov regularization theory. One appropriate regularized functional was established, and the functional was solved by the sensitivity coefficient and Newtonaphson iteration method. Moreover, the orthogonal experimental design was used to estimate the appropriate initial value and variation domain of each variable to decrease the number of iteration and improve the identification accuracy and efficiency. It illustrated a detailed case of AlSiTMg sand mold casting and the temperature measurement experiment was done. The physical properties of sand mold and the interracial heat transfer coefficient were identified at the meantime. The results indicated that the new regularization method was efficient in overcoming the ill-posedness of the inverse heat conduction problem and improving the stability and accuracy of the solutions.

Key design parameters and optimum method of medium- and high-velocity synchronous induction coilgun based on orthogonal experimental design

The energy conversion efficiency of a multistage synchronous induction coilgun(MSSICG) has become one of the key factors that restricts its industrialization. To improve the launch efficiency of medium-and high-velocity MSSICG,we propose an optimization design scheme combining orthogonal experimental design(OED) and self-consistent design method in this paper. The OED is introduced to reduce the number of iterations and improve the identification accuracy and efficiency. A self-consistent design model is established to overcome a defect that the parameters that need to be optimized will multiply as the number of coil stages increases. The influence of six factors(radial thickness of armature, axial length of armature, axial length of coil, capacitance, wire diameter, and slip speed) on the launch efficiency are then evaluated by range analysis. This work presents a valuable reference for optimizing medium-and high-velocity MSSICG.

A Spider Monkey Optimization Algorithm Combining Opposition-Based Learning and Orthogonal Experimental Design

As a new bionic algorithm,Spider Monkey Optimization(SMO)has been widely used in various complex optimization problems in recent years.However,the new space exploration power of SMO is limited and the diversity of the population in SMO is not abundant.Thus,this paper focuses on how to reconstruct SMO to improve its performance,and a novel spider monkey optimization algorithm with opposition-based learning and orthogonal experimental design(SMO^(3))is developed.A position updatingmethod based on the historical optimal domain and particle swarmfor Local Leader Phase(LLP)andGlobal Leader Phase(GLP)is presented to improve the diversity of the population of SMO.Moreover,an opposition-based learning strategy based on self-extremum is proposed to avoid suffering from premature convergence and getting stuck at locally optimal values.Also,a local worst individual elimination method based on orthogonal experimental design is used for helping the SMO algorithm eliminate the poor individuals in time.Furthermore,an extended SMO^(3)named CSMO^(3)is investigated to deal with constrained optimization problems.The proposed algorithm is applied to both unconstrained and constrained functions which include the CEC2006 benchmark set and three engineering problems.Experimental results show that the performance of the proposed algorithm is better than three well-known SMO algorithms and other evolutionary algorithms in unconstrained and constrained problems.

Orthogonal experiment design of EMI of security monitoring system in coal mines

Security monitoring system of coal mines is indispensable to ensure the safe and efficient production of colliery. Due to the special and narrow underground field of the coal mine, the electromagnetic interference can cause a series of misstatements and false positives on the monitoring system, which will severely hamper the safe production of coal industry. In this paper, first, the frequency characteristics of the interference source on the power line are extracted when equipment runs normally. Then the finite difference time domain method is introduced to analyze the effects of the electromagnetic interference parameters on the security monitoring signal line. And the interference voltage of the two terminal sides on the single line is taken as evaluating indexes. Finally, the electromagnetic interference parameters are optimized by orthogonal experimental design based on the MATLAB simulation on the normal operation of equipment.

Cavitation Optimization for a Centrifugal Pump Impeller by Using Orthogonal Design of Experiment

Cavitation is one of the most important performance of centrifugal pumps. However, the current optimization works of centrifugal pump are mostly focusing on hydraulic efficiency only, which may result in poor cavitation performance. Therefore, it is necessary to find an appropriate solution to improve cavitation performance with acceptable efficiency. In this paper, to improve the cavitation performance of a centrifugal pump with a vaned diffuser, the influence of impeller geometric parameters on the cavitation of the pump is investigated using the orthogonal design of experiment （DOE） based on computational fluid dynamics. The impeller inlet diameter D1, inlet incidence angle Aft, and blade wrap angle ~0 are selected as the main impeller geometric parameters and the orthogonal experiment of L9（3＂3） is performed. Three-dimensional steady simulations for cavitation are conducted by using constant gas mass fraction model with second-order upwind, and the predicated cavitation performance is validated by laboratory experiment. The optimization results are obtained by the range analysis method to improve cavitation performance without obvious decreasing the efficiency of the centrifugal pump. The internal flow of the pump is analyzed in order to identify the flow behavior that can affect cavitation performance. The results show that D1 has the greatest influence on the pump cavitation and the final optimized impeller provides better flow distribution at blade leading edge. The final optimized impeller accomplishes better cavitation and hydraulic performance and the NPSHR decreases by 0.63m compared with the original one. The presented work supplies a feasible route in engineering practice to optimize a centrifugal pump impeller for better cavitation performance.

Optimization of rheological parameter for micro-bubble drilling fluids by multiple regression experimental design

In order to optimize plastic viscosity of 18 mPa·s circulating micro-bubble drilling fluid formula,orthogonal and uniform experimental design methods were applied,and the plastic viscosities of 36 and 24 groups of agent were tested,respectively.It is found that these two experimental design methods show drawbacks,that is,the amount of agent is difficult to determine,and the results are not fully optimized.Therefore,multiple regression experimental method was used to design experimental formula.By randomly selecting arbitrary agent with the amount within the recommended range,17 groups of drilling fluid formula were designed,and the plastic viscosity of each experiment formula was measured.Set plastic viscosity as the objective function,through multiple regressions,then quadratic regression model is obtained,whose correlation coefficient meets the requirement.Set target values of plastic viscosity to be 18,20 and 22 mPa·s,respectively,with the trial method,5 drilling fluid formulas are obtained with accuracy of 0.000 3,0.000 1 and 0.000 3.Arbitrarily select target value of each of the two groups under the formula for experimental verification of drilling fluid,then the measurement errors between theoretical and tested plastic viscosity are less than 5%,confirming that regression model can be applied to optimizing the circulating of plastic-foam drilling fluid viscosity.In accordance with the precision of different formulations of drilling fluid for other constraints,the methods result in the optimization of the circulating micro-bubble drilling fluid parameters.

Modeling Approach and Analysis of the Structural Parameters of an Inductively Coupled Plasma Etcher Based on a Regression Orthogonal Design

The geometry of an inductively coupled plasma （ICP） etcher is usually considered to be an important factor for determining both plasma and process uniformity over a large wafer. During the past few decades, these parameters were determined by the ＂trial and error＂ method, resulting in wastes of time and funds. In this paper, a new approach of regression orthogonal design with plasma simulation experiments is proposed to investigate the sensitivity of the structural parameters on the uniformity of plasma characteristics. The tool for simulating plasma is CFD-ACE＋, which is commercial multi-physical modeling software that has been proven to be accurate for plasma simulation. The simulated experimental results are analyzed to get a regression equation on three structural parameters. Through this equation, engineers can compute the uniformity of the electron number density rapidly without modeling by CFD-ACE＋. An optimization performed at the end produces good results.

Mathematical model for abrasive suspension jet cutting based on orthogonal test design

This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.

A study of storage conditions for pre-mashed fried Semen Zizyphi Spinosae using a multi-factor orthogonal design

Background:To facilitate the preparation of traditional Chinese medicines they are pre-mashed,i.e.,mashed in advance.However,storage conditions for pre-mashed traditional Chinese medicines are based on subjective judgments of pharmacists,and the best storage conditions have not generally been determined.Semen Zizyphi Spinosae is a commonly used traditional Chinese medicine,and it is usually used after it is fried.The medicine needs to be mashed in a timely manner to ensure its effectiveness.The Chinese Pharmacopoeia provides a limit for its aflatoxin content.Methods:The orthogonal experimental design method optimizes the best plan for pre-mashed fried Semen Zizyphi Spinosae.Experimental conditions were defined using the L^(9)(3^(4))orthogonal design table.Four factors and three levels were used to study storage conditions.The four factors and three levels are as follows:storage temperature(10°C,20°C,and 30°C),storage humidity(45%,60%,and 75%),storage times(10,20 and 30 days),and particle sizes for the powder(coarsest,coarse and medium powders).The contents of jujuboside A,spinosin,aflatoxin B1,total aflatoxins(aflatoxins B1,B2,G1,and G2),moisture,total ash,acid value,and saponification values were measured.Results:The results demonstrated that the highest jujuboside A and spinosin contents were obtained using a storage temperature of 20°C,a storage humidity of 75%,a storage time of 10 days,and with a coarse powder particle size.Aflatoxin B1 and total aflatoxins(aflatoxins B1,B2,G1 and G2)were not detected under these conditions.Conclusion:There is no requirement for traditional Chinese medicines to be pre-mashed.This study evaluated various storage conditions for pre-mashed fried Semen Zizyphi Spinosae,and considered the influence of four factors on the contents of jujuboside A,spinolin and aflatoxin for quality control to provide a reference for other pre-mashed traditional Chinese medicines.

Enumeration of Strength Three Orthogonal Arrays and Their Implementation in Parameter Design

This paper describes the construction and enumeration of mixed orthogonal arrays (MOA) to produce optimal experimental designs. A MOA is a multiset whose rows are the different combinations of factor levels, discrete values of the variable under study, having very well defined features such as symmetry and strength three (all main interactions are taken in consideration). The applied methodology blends the fields of combinatorics and group theory by applying the ideas of orbits, stabilizers and isomorphisms to array generation and enumeration. Integer linear programming was used in order to exploit the symmetry property of the arrays under study. The backtrack search algorithm was used to find suitable arrays in the underlying space of possible solutions. To test the performance of the MOAs, an engineered system was used as a case study within the stage of parameter design. The analysis showed how the MOAs were capable of meeting the fundamental engineering design axioms and principles, creating optimal experimental designs within the desired context.

Multi-species particle swarms optimization based on orthogonal learning and its application for optimal design of a butterfly-shaped patch antenna

A new multi-species particle swarm optimization with a two-level hierarchical topology and the orthogonal learning strategy(OMSPSO) is proposed, which enhances the global search ability of particles and increases their convergence rates. The numerical results on 10 benchmark functions demonstrated the effectiveness of our proposed algorithm. Then, the proposed algorithm is presented to design a butterfly-shaped microstrip patch antenna. Combined with the HFSS solver, a butterfly-shaped patch antenna with a bandwidth of about 40.1% is designed by using the proposed OMSPSO. The return loss of the butterfly-shaped antenna is greater than 10 d B between 4.15 and 6.36 GHz. The antenna can serve simultaneously for the high-speed wireless computer networks(5.15–5.35 GHz) and the RFID systems(5.8 GHz).

Orthogonal genetic algorithm for solving quadratic bilevel programming problems

A quadratic bilevel programming problem is transformed into a single level complementarity slackness problem by applying Karush-Kuhn-Tucker（KKT） conditions.To cope with the complementarity constraints,a binary encoding scheme is adopted for KKT multipliers,and then the complementarity slackness problem is simplified to successive quadratic programming problems,which can be solved by many algorithms available.Based on 0-1 binary encoding,an orthogonal genetic algorithm,in which the orthogonal experimental design with both two-level orthogonal array and factor analysis is used as crossover operator,is proposed.Numerical experiments on 10 benchmark examples show that the orthogonal genetic algorithm can find global optimal solutions of quadratic bilevel programming problems with high accuracy in a small number of iterations.

Influence of plasma-MIG welding parameters on aluminum weld porosity by orthogonal test

The plasma-MIG welding torch was developed.5A06 aluminum alloys with V-grooves were welded in a single pass in the plasma-MIG welding process and the joints were examined by X-ray diffractometry analysis and mechanical tests.The orthogonal experimental design was used to study the influence of plasma-MIG welding parameters on the aluminum weld porosity.The mixed orthogonal matrix L16(4 4×2 3) and analysis of variance (ANOVA)technique were employed to optimize the welding parameters.The experimental results indicate that the effect of plasma gas flow rate is dominant,the secondary factors are MIG welding voltage,welding speed,wire feed rate and plasma current in turn.Confirmation experiments were conducted under optimum conditions and there was almost no porosity in the welded joints,thus good mechanical performance joints were obtained.

Solution for integer linear bilevel programming problems using orthogonal genetic algorithm

An integer linear bilevel programming problem is firstly transformed into a binary linear bilevel programming problem, and then converted into a single-level binary implicit programming. An orthogonal genetic algorithm is developed for solving the binary linear implicit programming problem based on the orthogonal design. The orthogonal design with the factor analysis, an experimental design method is applied to the genetic algorithm to make the algorithm more robust, statistical y sound and quickly convergent. A crossover operator formed by the orthogonal array and the factor analysis is presented. First, this crossover operator can generate a smal but representative sample of points as offspring. After al of the better genes of these offspring are selected, a best combination among these offspring is then generated. The simulation results show the effectiveness of the proposed algorithm.

Experimental investigation of key parameters pertinent to multi-hole orifice throttling characteristic

This study firstly defines a set of arrangement rule for perforated holes of multi-hole orifice(MO), and then presents three critical geometrical parameters including total number of performated hole, equivalent diameter ratio and distribution density of perforated holes, which are to quantify MO structure. This paper built the throttling test apparatus for nice test MO plates, which were designed according to orthogonal theory. The experiments were conducted to investigate the effect of three critical geometerical parameters on the pressure loss coefficient of test MOs. Results show that equivalent diameter ratio is the dominant prameter affecting MO throttling characterstic.

Control-Relevant Identification Test Design for Open-Loop Experiment

An optimal experiment design (DED) with respect to the use of designing model-base controller was studied. The mean squared error at the setpoint is chosen as the performance criterion. Simple design formulas are derived based on the asymptotic theory. The signal is used for the open loop experiment. The design constraint is the power of the process signal or the process input signal. The results give guideline for identification application.

基于OED-GRA评价模型的采场岩体参数敏感性分析

针对岩体参数对采场稳定性的敏感性问题,提出一种正交—灰色关联评价模型(OED-GRA),可分析相互影响的多种岩体参数与采场稳定性之间的关联度。选取Hoek-Brown准则岩体参数中的地质强度指标GSI、岩石单轴抗压强度σci、岩石软硬程度常数mi、岩体扰动系数D等4个因素,采用正交试验方法和数值模拟方法进行16次典型的试验。取顶板沉降位移、顶板水平应力、矿柱水平位移、矿柱竖直应力4个指标进行指标满意度的敏感性分析。基于灰色关联理论,求得各评价指标与岩体性质参数的灰色关联系数,并获得Hoek-Brown准则岩体性质参数与Mohr-Coulumb准则岩体力学参数之间的关联系数。研究结果表明,GSI对采场稳定的敏感性最大,D的敏感度明显最小,σci、mi参数敏感性较GSI次之。采用正交灰色关联评价模型,避免了单因素分析敏感性的局限,同时可分析不同量纲的多因素关联度,结论更为客观、可靠,为多因素关联的敏感性分析提供一种新的思路。

基于RF-GWO的水利工程地质渗透系数智能反演分析

地质渗透系数是准确分析水利工程渗流的关键参数。针对传统反演方法计算效率低、精度差的问题,采用有限元正演模型和正交试验设计构建渗透系数反演样本集,建立了基于随机森林(RF)算法的渗流计算代理模型;在此基础上,引入灰狼优化(GWO)算法,提出了基于RF-GWO的渗透系数智能反演方法,并以Z抽水蓄能电站为研究案例进行了验证。结果表明:RF模型对各钻孔水位预测结果均接近实测值,性能优于CART和BP模型;GWO可搜寻到地质最佳渗透系数,钻孔水位反演结果合理,相对误差最大为0.42%,精度满足工程要求,计算的天然渗流场分布形态也符合一般山体渗流场分布规律。建立的反演模型能够快速准确地推断工程区地层渗透系数,具有实际工程应用价值。

Experimental Optimization of Jet Self-Priming Centrifugal Pump Based on Orthogonal Design and Grey-Correlational Method

The novel jet self-priming centrifugal pump,as important modern irrigation equipment,is widely used in large-scale irrigation,mine drainage and so on.In order to improve the profile streamline of blade,the inlet shape of impeller was designed as distorted and the outlet shape as cylindrical,which can not only improve the pump efficiency,but also shorten the self-priming time.Further,the novel jet self-priming system was proposed,by employing the jet nozzle and check valve to improve the velocity of self-priming.Meanwhile,nine different structure jet nozzles were designed based on the orthogonal design method,and the relevant self-priming experiments were performed on I level accuracy test bench in Jiangsu University.According to the greycorrelational analysis,the influence of the nozzle geometry parameters on the self-priming performance was obtained.The relationship between self-priming time and self-priming height was discussed.The test results showed that the hydraulic design of jet self-priming centrifugal pump was reasonable;all indicators met the Chinese national standard;the head reached 21.04 m and efficiency was 72.8%under the design flow condition.What is more,the self-priming performance was obviously improved by adjusting the geometrical parameters of nozzle.When the height of the self-priming process was 5.3 m,the self-priming time reached 62 s,which was much shorter than the national standard.Therefore,this research could provide reference for designing the structure of jet self-priming centrifugal pump.