Tuning of a control compensator from the first generation with comparison with compensators from the second compensator generation

The paper investigates the tuning of a second order compensator from the first compensators generation when used to control a highly oscillating second order process. It compares the performance characteristics of the control system comprising this compensator to control the highly oscillating second order process with those resulting from the use of five compensators from the second compensators generation. The comparison covers three time-based characteristics: maximum percentage overshoot, settling time and steady-state error. All the compensators are tuned and the analysis results help control engineers to select appropriate compensators according to the desired performance characteristic for a specific application.

Multiple performance characteristic index optimization of dimensional accuracy and geometrical shape angle in turn-mill multitasking machining

Multiple performance objectives in turn-mill multitasking machining are investigated using the Taguchi method combined with the fuzzy theory. Using these two methods, optimized processing parameters can be rapidly identified to obtain optimized dimensional accuracy and geometrical shape angle, thus reducing machining cost and time. Herein, control factors for determining the single objective optimization parameter using the Taguchi robust process L9(34) orthogonal table were spindle speed (rpm), feed (mm/min), C-axis brake pressure (kg/cm2), axial cutting depth (mm), with dimensional accuracy and geometrical shape angle as objective characteristics. Then, signal-to-noise ratios of different groups were generated by gray correlation according to the experimental sequence to obtain the gray correlation coefficient for the calculation of the multiple performance characteristic index (MPCI). The MPCI results demonstrated that optimized dimensional accuracy was 0.005 mm and optimized geometrical shape angle was 0.004°. The optimized MPCI parameters were A3 (4000 rpm), B3 (250 mm/min), C3 (30 kg/cm2), and D3 (1.5 mm). It can reduce the processing for burr elimination and tool wear reduction by MPCI optimized process parameters.

A-KA Model: an Optimization of the Stock’s Portofolio

The elaborate proposes a compact alternative methodology to the classical stocks portfolio optimization based on the normal distribution of the returns of the assets named Adaptable - Kurtosis Asymmetry model (A-KA). In the financial theory is well-known that odd-order moments of a distribution describe a particular performance characteristic; on the contrary, the even-order moments tell a precise sense of risk of a distribution of returns. If it is true that, in general terms, minimizing the variance also minimizes the volatility of portfolio return is also true that we should minimize the kurtosis to get away from unpleasant situations in case “Extreme” events occur, especially if negative. The idea behind this paper is to exploit the four moments of return’s distributions, optimizing an alternative risk indicator to variance, such as the kurtosis of the final distribution of the portfolio, making constraints on distributive asymmetry, in a dynamic underlying logic.

Numerical and Experimental Investigation of the Fan with Cycloidal Rotor

In this paper, the investigation of the cycloidal rotor fan (CRF) was presented. A CRF with four blades of the NACA0012 profile was used for the analysis. The CFD calculations were carried out by means of Ansys CFX commercial software. The experimental tests were done using velocity field measurement with the LDA technique. Numerical results were compared with experimental measurement in terms of velocity values. The CRF performance characteristic was prepared on the basis of experimental and numerical results.