Motion parameter tuning for servomotor packs based on learning automata method

Abstract

In this paper, we investigate the use of the learning automata method in tuning the motion parameters of servomotor packs with implicit control structures. For commercial servomotor packs, it is difficult to design motion parameters using systematic approaches. However, tuning these motion parameters is very important. Here, the tuning process is automated using a learning automata method that operates through interactions with unknown environments using a stochastic trial and error process; it also provides additional convergence information through probability density functions. Moreover, a tuning method that matches the dynamic responses of all synchronous motion axes is developed for increasing the contouring accuracy of multi‐axis systems. The obtained experimental results indicate that the proposed method can effectively tune the motion parameters. As compared to tuning methods that do not consider matched dynamic responses, the proposed method achieves a reduction of 46.6% in the roundness error.     

Two-dimensional coupled electro-optic delayed feedback system with varying parameters

In this paper, a two-dimensional coupled electro-optic delayed feedback system with varying parameters is proposed. The phase diagram, bifurcation diagram, approximate entropy and permutation entropy are used for illustrating its dynamics performances. Results show that this system has a high complexity compared to other systems. Furthermore, this system can conceal the time delay effectively against the auto-correlation function, delayed mutual information and permutation information analysis method, which greatly improve the security performance. Summarily, our model is more complex and can conceal the time delay with a lower gain coefficient compared to the other proposed proposals.     

含氧化锆的氧化物系统计算相图研究与进展

氧化锆是一种重要的高性能陶瓷材料，由于其优良的力学和电学性能。在结构陶瓷和功能陶瓷两个都有着广泛的应用前景，本文在简述计算相图发展和原理的基础上，综述了近年来对含氧化锆系统计算相图的研究，总结了一些重要体系的研究结果，提出计算相图方法将对该系统材料的组分设计起重大的促进作用。     

Experimental investigation and thermodynamic calculation of phase equilibria in the In–Sb–Zn ternary system

Binary thermodynamic data, successfully used for phase diagram calculations of binary systems In–Sb, In–Zn, and Sb–Zn, were used for prediction of phase equilibria in ternary In–Sb–Zn system. The liquidus projection, invariant equilibria and several vertical sections were calculated using the CALPHAD method. Alloys, situated along three calculated vertical sections, were investigated by differential thermal analysis (DTA). The experimentally determined phase transition temperatures were compared with predicted results. Phase identification of selected samples was done using scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDS).     

Phase transformations and phase equilibria in Ti -25V -N system at 1200°C

Abstract

The nature of phase transformations and phase equilibria in the Ti- V - N system with about 20 at.-%V and 11 -15 at.-%N has been studied at 1200°C. The results obtained for the titanium rich corner of the Ti - V- N phase diagram provide new information on phase coexistence and the composition of particular phases in this system. Thermodynamic calculations, based on the use of thermodynamic parameters from the three binary subsystems, together with newly assessed thermodynamic parameters published previously, were carried out. Reasonable agreement was obtained between the experiment and the calculations.     

二元合金相图进展及基于第一性原理新方法

材料设计已成为各国争相发展的技术之一,作为材料制备的索骥图,相图及其热力学参数的计算方法受到了越来越多的重视.概述了相图及热力学研究的进展,对比分析了经典的热力学计算方法和前沿研究,并着重分析了目前流行的第一性原理计算和CALPHAD方法相结合的计算进展,提出并验证了基于第一性原理的带温度参数的热力学数据计算方法,展望了此类方法对预测材料物性和冶金设计优化的前景.     

Evaluation of the thermodynamic properties of tungsten

A new evaluation of the thermodynamic properties of tungsten has been made. A set of parameters describing the Gibbs energy of each individual phase as a function of temperature and pressure is given. The experimental information on the P, T phase diagram and the thermodynamic data are compared with calculations made using the presented set of parameters.     

中碳高合金高强度钢线膨胀测量中奥氏体-铁素体相变过程分析

线膨胀测量是获取钢铁材料固态相变动力学信息的一种重要手段,而从线膨胀测量结果提取相变动力学信息的杠杆法则,不适用于两相或者多相连续析出的过程,因而在计算相变体积分数时会产生很大的系统误差.以中碳高合金高强度钢(MCHAHS)的奥氏体一铁素体相变过程为主要研究对象,通过确定冷却过程中各生成相的晶格常数随温度的变化关系,发展了一种新的由线膨胀量信息提取相变动力学信息的计算方法,从而得到了MCHAHS钢转变过程中铁素体和珠光体体积分数随温度的变化关系,计算结果与验证性实验结果吻合良好.     

Phase relations in the CaMnO system

The use of solid solution precursors is introduced as an effective low temperature synthesis technique which facilitates solid state reaction in selected mixed metal oxide systems. This synthesis technique has been used to study phase relations in the manganese-rich portion of the CaMnO system at temperatures below 1000°C, and has resulted in the assemblage of a new isobaric (P_O2 = 1.0 atm), subsolidus phase diagram. This diagram contains several low temperature phases having the following compositions: Ca₂Mn₃O₈, CaMn₃O₆, CaMn₄O₈ and CaMn₇O₁₂. The experimental results of this study along with literature data are used to present a proposed isobaric (P_O2 = 0.2 atm) phase diagram for the entire CaMnO system.     

低温区间的Fe-N二元相图理论分析

采用亚点阵的化合物能模型计算低温区间Fe-N二元相图。计算结果表明,25～350℃低温区,分别存在着α-Fe(N)和γ＇-Fe4N,γ＇-Fe4N和ε-Fe₂N_1-x二相平衡。α-Fe(N),γ＇-Fe₄N,ε-Fe₂N_1-x均为热力学稳定相。依据Guillermet和Du的热力学性质参数计算的低温区间Fe-N二元相图与现有实验数据相符。     

聚醚砜四元制膜液体系的相图计算

以Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论为基础，对ＰＥＳ－ＰＧ－ＮＭＰ＿Ｈ２Ｏ＿）聚醚砜丙二醇－Ｎ－甲基－２－哟咯烷酮水）四元制液体系的相图进行了计算，利用三元相图考察Ｈ２Ｏ和ＰＧ对液－液相分离的影响，在三元的理论的基础上提出了低分子量添加剂的卤元改性Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ理论，并提出了一种获得四元相图的方法，利用四元相图能较争地描述四元体系，利用改性的四元理论，能了地理解该种体系的液－液相分离行为。     

Reflection Phase Measurements for Ultrasonic NDE of Titanium Diffusion Bonds

The adoption of diffusion bonding in fracture critical titanium components has been limited by the complications that macroscopic anisotropy introduces to typical ultrasonic inspections. Previous attempts to overcome these limitations by using signal phase to extract otherwise hidden interface information showed promise but were susceptible to measurement error and proved impractical for typical aerospace component geometries. In the work presented here, significant improvements to the existing phase measurement approach are proposed alongside adaptations that permit its broader practical implementation. The principal parameters that affect the phase analysis of ultrasonic signals were investigated and their optimisation resulted in up to an order of magnitude improvement in phase measurement reliability, even at low signal-to-noise ratios. The application of these optimised parameters without a priori knowledge of the signal arrival time in an otherwise noisy waveform is illustrated, and the sensitivity of the approach to ambient temperature and annealing effects is also explored.     

Phase diagram of Hf-H alloy

The equilibrium phase diagram was investigated for hafnium-hydrogen binary system. Using a modified Sieverts apparatus, pressure-composition-temperature (P-C-T) relationships were measured for the hafnium-hydrogen systems at low temperature. Because the allotropic transformation temperature of pure hafnium is about 2000 K, the hafnium-hydrogen phase diagram could not be obtained directly at high temperature. Therefore, based on the Duhem-Margules equation, the partial molar free energy of hydrogen can be estimated at high temperature.     

Global first harmonic bifurcation diagram for odd piecewise linear control systems

The describing function method (used normally as a first approximation to study the existence and the stability of periodic orbits) is used here to analyze the dependence of periodic orbits on the parameters of autonomous systems. The method can be applied to a large class of nonlinear systems but, for simplicity, attention here is paid to a class of single-input, single-output control systems with a piecewise linear character- istic function. A first approach to the bifurcation diagram associated with the periodic orbits of such systems, called a first harmonic bifurcation diagram' is obtained for two and three dimensions. This diagram in two dimensions describes all the qualitative behaviour of such systems. Although this is not the case in three dimensions, the information contained in the corresponding first harmonic bifurcation diagram is of great value. It shows much of the complexity of the periodic structure that can be found in such three-dimensional systems; in fact, part of the first harmonic bifurcation diagram coincides with the actual bifurcation diagram     

位相测量轮廓术的仿真研究：系统结构参数的影响

在一个结构光三维传感器的计算机仿真系统上，研究了由观察光场重建三维面形的过程，以及系统主要结构参对位相测量轮廓术的影响，提出了根据对标准平面的测量结果对参数进行修正的方法，为实际系统的结构调整和参数校正提供了一种新的途径。     

The Calculation of Phase Equilibrium Between Structural Phases with a Magnetic Transition by the Cluster Variation Method

The phase equilibrium between structural phases with a magnetic transition is investigated using the CV-pair approximation of the cluster variation method (CVM). By the geometric analysis of the grand potential, it is demonstrated that the grand potential and effective chemical potential of the different structural phases with a magnetic transition can be separated into paramagnetic and magnetic terms. In addition, the molar grand potential-effective chemical potential curve can be obtained from the relevant molar energy diagram. A calculation method for the phase equilibrium between structural phases with a magnetic transition is proposed; this method is applied to the / phase equilibrium in the Fe–Mn binary system, and the calculated phase diagram closely approximates the experimental diagram.     

Solvus Composition Paths in Multicomponent Alloys—Experimental Approach and Correlation with Calphad Calculations for the Example Al–Mg–Si

An experimental approach employing temperature and concentration gradients is presented that is suitable for determining a sequence of solvus concentrations in a single experimental cycle. The Al–Mg–Si system is used as an example. Al solid solutions (“(Al)”) with different compositions and Mg₂Si precipitates were equilibrated in the temperature range between 350 and 550 °C. The equilibrium compositions of (Al) were measured by energy dispersive X‐ray spectroscopy in the transmission electron microscope. The coupled temperature‐concentration values represent a path on the ternary solvus surface. Calphad calculations using different thermodynamic data sets were carried out to relate the experimental results to phase diagram evaluations. The measured solvus path agrees well with solvus data calculated with most recent thermodynamic parameter sets. The experimental approach can be applied to multicomponent alloys irrespective of their number of components with the same experimental effort. The efficiently generated solubility data are suitable to support phase diagram evaluations of multicomponent systems by the Calphad method.