In order to make temperature increases rate of the heating module of leather shrinkage temperature apparatus meets leather shrinkage temperature measurement standards in national light industry, we used a temperature sensor to collect the current temperature value of the heating medium. A single-chip microcomputer (SCM) controls the turn-on and turn-off time of triac to ensure a uniform and constant medium temperature increase at (2±0.2)°C/min through negative feedback control. We were also able to transmit the temperature-time data to a host computer in real time via RS232 serial port for further study. Experiments show that this heating module gives a good control effect to the whole system and meets the measurement standards. It is particularly important to improve the accuracy of measuring shrinkage temperature of leather.
A recursive algorithm for the two-stage empirical frequency-domain optimal parameter (EFOP) estimation method was proposed. The EFOP method was a novel system identification method for Black-box models that combines time-domain estimation and frequency-domain estimation. It has improved anti-disturbance performance, and could precisely identify models with fewer sample numbers. The twostage EFOP method based on the boot-strap technique was generally suitable for Black-box models, but it was an iterative method and takes too much computation work so that it did not work well online. A recursive algorithm was proposed for disturbed stochastic systems. Some simulation examples are included to demonstrate the validity of the new method.EFOP estimation, Black-box models, two-stage EFOP, recursive algorithm 1 Problem statement Many identification methods [1] for disturbed systems have been proposed in the past few decades. They can be categorized as either time-domain estimation or frequency-domain estimation methods. The prediction error (PE) method, maximum likely-hood (ML) method and instrument variable (IV) method are time-domain estimation methods. Time-domain estimation is simple and can be implemented easily, but it cannot characterize the frequency features, such as the transfer functions of the systems. To exploit the frequency-domain, some frequency-domain estimation methods [2−4] have also been proposed, but some of them are difficult to implement and others have poor accuracy.The empirical frequency-domain optimal parameter (EFOP) [5−7] estimation method is a novel method for Black-box models, which combines both time-domain and frequency-domain estimation. The criterion that plays an important role in the parameter estimation used in the EFOP
Aqueduct is the key structure in water conveyance engineering, which may be damaged during earthquake. Although numerous water conveyance designs have been built, the current state of researches on aqueduct aseismic design is inadequate. In this paper, based on the fluid-structure interaction dynamics and response spectra analysis, a simplified analysis method was proposed to evaluate the transverse seismic response of aqueducts, and the simplified calculating results were compared with the results of the nonlinear finite element calculation of fluid-structure interaction and experimental results. The results showed that the simplified analysis method put forward in this paper could be used to evaluate the transverse seismic response of aqueducts. In the condition that the pier height is less than 40 m, the first-order lateral vibration mode of the aqueduct has a higher model contribution rate; the simplified calculation method can achieve extremely high accuracy. The simplified calculation precision decreases as the height increases when the pier height exceeds 40 m.
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