Jayaram Sabavath, Venkatesan Nithya
School of Electrical Engineering, Vellore Institute of Technology, Chennai, 600127, India.
Sci Rep. 2024 Dec 30;14(1):31714. doi: 10.1038/s41598-024-82258-1.
Spherical tanks have been predominantly used in process industries due to their large storage capability. The fundamental challenges in process industries require a very efficient controller to control the various process parameters owing to their nonlinear behavior. The current research work in this paper aims to propose the Approximate Generalized Time Moments (AGTM) optimization technique for designing Fractional-Order PI (FOPI) and Fractional-Order PID (FOPID) controllers for the nonlinear Single Spherical Tank Liquid Level System (SSTLLS). This system features a large dead time, and its real-time modeling generally represents a Single Input Single Output (SISO) model. However, in practice, the derived SISO model is often a First Order Plus Dead Time (FOPDT) model, necessitating an effective controller to maintain the tank's steady-state level. In this research, the proposed AGTM method, based on the conventional Proportional Integral (PI) and Proportional Integral Derivative (PID) controllers, is compared with the FOPI and FOPID controllers for the nonlinear SSTLLS. The performance of these controllers is contrasted using metrics such as Integral Squared Error (ISE) and Integral Absolute Error (IAE), as well as time-domain characteristics containing Rise time, Peak time, Settling time, Peak overshoot, and Steady-state error. The implementation of the aforementioned controllers is done in simulation and real-time employing the MATLAB software environment and the Data Acquisition (DAQ) device National Instrument NI-DAQmx 6211. The simulation and experimental results demonstrate the exceptional performance of the designed Fractional-Order controllers based on the proposed method which offers an increased degree of freedom despite the more complex design process.
由于具有较大的存储能力，球形储罐在流程工业中得到了广泛应用。流程工业中的基本挑战要求有一个非常高效的控制器来控制各种过程参数，因为它们具有非线性行为。本文当前的研究工作旨在提出近似广义时间矩（AGTM）优化技术，用于为非线性单球形储罐液位系统（SSTLLS）设计分数阶PI（FOPI）和分数阶PID（FOPID）控制器。该系统具有较大的死区时间，其实时建模通常表示为单输入单输出（SISO）模型。然而，在实际中，推导得到的SISO模型通常是一阶加死区时间（FOPDT）模型，这就需要一个有效的控制器来维持储罐的稳态液位。在本研究中，将基于传统比例积分（PI）和比例积分微分（PID）控制器提出的AGTM方法与用于非线性SSTLLS的FOPI和FOPID控制器进行了比较。使用诸如积分平方误差（ISE）和积分绝对误差（IAE）等指标，以及包含上升时间、峰值时间、调节时间、峰值超调量和稳态误差的时域特性来对比这些控制器的性能。上述控制器的实现是在MATLAB软件环境和数据采集（DAQ）设备National Instrument NI - DAQmx 6211中进行仿真和实时操作的。仿真和实验结果表明，基于所提出方法设计的分数阶控制器具有卓越的性能，尽管设计过程更为复杂，但却提供了更高的自由度。
