Implementation of a PID Type Sliding-Mode Controller Design Based on Fractional Order Calculus for Industrial Process System

This paper is devoted to designing a fractional order Proportional Integral Derivative (PID) type sliding mode control method (FO-PIDSMC) for a non-linear liquid level coupled tank process system. By considering the individual advantages of the FO calculus and PID type SMC method, this proposed FO-PIDSMC technique is designed to integrate the FO calculus method with PID type SMC scheme to obtain an accurate and robust liquid level tracking in terms of the predefined reference trajectory. The real-time experimental results of the proposed controller suggest a dramatic improvement over the traditional process system controller methods in both trajectory tracking and required control action.

Multipoint Wave Measurement in Tuned Liquid Damper Using Laser Doppler Vibrometer and Stepwise Rotating Galvanometer Scanner

Liquid dampers, such as tuned liquid dampers (TLDs), are employed to improve serviceability by reducing wind-affected building vibrations. In order to maximize the vibration suppression efficiency of the liquid damper, the tuning frequency of the liquid damper should match the natural frequency of the building. Experimental evaluation of the tuning frequency of a liquid damper performed in a factory prior to installation in a building is a critical task to ensure correct performance, and for this, multipoint measurement of the TLD is required. In this study, a novel liquid level measurement system combining Laser Doppler Vibrometer (LDV) and a stepwise rotating galvanometer scanner was developed to observe liquid sloshing in TLD. The proposed system can measure the liquid level at multiple points simultaneously with a single laser point. In the experimental phase, the liquid damper’s natural frequency and mode shape are experimentally evaluated utilizing the developed system. The performance of the proposed system was verified by comparison with the video sensing system.

Fiber laser with built-in FBG and LPFG for simultaneous two parameters sensing

This work aims to measure the liquid level and temperature at the same time. We propose a fiber laser based on Bragg grating (FBG) and a long-period fiber grating (LPFG) for simultaneously two-parameter sensing. It has one wavelength peak induced by the FBG and one central dip induced by the LPFG. The resulting temperature varies from 25 °C to 50 °C in 7.5 nm wavelength drifts of LPFG with linearity R 2 of 0.9994. The sensitivity of the FBG liquid level sensing will be affected by the temperature change, ranging from—0.12 nm cm−1 at low temperature to—0.004 nm cm−1 at high temperature, and the linearity R 2 is about 0.9967. Thanks to the laser cavity, the proposed fiber laser with an extensive dynamic range could be used for remote monitoring.