Open AccessFirst‐order plus time‐delay systems under the effects of actuator rate limit
Author(s) -
Yuan Jie,
Han Jie,
Chai Lin,
Fei Shumin,
Chen Yang Quan
Publication year - 2020
Publication title -
iet control theory and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.059
H-Index - 108
eISSN - 1751-8652
pISSN - 1751-8644
DOI - 10.1049/iet-cta.2019.1110
Subject(s) - control theory (sociology) , actuator , limit (mathematics) , controller (irrigation) , describing function , sensitivity (control systems) , limit cycle , computer science , mathematics , engineering , control (management) , physics , mathematical analysis , electronic engineering , nonlinear system , quantum mechanics , artificial intelligence , agronomy , biology
Actuator rate limit phenomenon is ubiquitous in control systems, but it has always been neglected in practical engineering. Especially, few papers are published to investigate the system identification while considering the rate limit. Step function is commonly used in parameter estimation and its first‐order derivative at the step time goes to infinity, which is not affordable by real actuators. As a result, the rate limit slows down the system response speed, misleads the parameter identification, and subsequently affects the controller design and deteriorates the control performance. This study proposes both graphical method and curve fitting method to identify the first‐order plus time‐delay (FOPTD) systems with consideration of the actuator rate limit effect whose limit value is unknown. Quantitative analyses of the parameter mismatch in the traditional FOPTD model and parameter sensitivity analyses are also carried out. Both simulation results and experimental results have shown the necessity and feasibility of defining a new model structure which includes the rate limit value.