Original scientific paper
https://doi.org/10.1080/00051144.2020.1864186
Self-tuning state-feedback control of a rotary pendulum system using adjustable degree-of-stability design
Omer Saleem
; Department of Electrical Engineering, National University of Computer and Emerging Sciences, Lahore, Pakistan
Mohsin Rizwan
; Department of Mechatronics and Control Engineering, University of Engineering and Technology, Lahore, Pakistan
Khalid Mahmood-ul-Hasan
; Department of Electrical Engineering, University of Engineering and Technology, Lahore, Pakistan
Abstract
This paper formulates an original hierarchical self-tuning control procedure to enhance the disturbance-rejection capability of under-actuated rotary pendulum systems against exogenous disturbances. The conventional state-feedback controllers generally make a trade-off between the robustness and control effort in a closed-loop system. To combine the aforementioned characteristics into a single framework, this paper contributes to develop and augment the baseline
Linear-Quadratic-Regulator (LQR) with a novel “adjustable degree-of-stability design” module. This augmentation dynamically relocates the system’s closed-loop poles in the stable (left-half) region of the complex plane by dynamically adjusting a single hyper-parameter that modifies the constituents of LQR’s performance index. The hyper-parameter is adaptively modulated online via a pre-calibrated hyperbolic-secant-function that is driven by state-error variables. The performance of the proposed adaptive controller is benchmarked against fixed-gain controllers via credible hardware experiments conducted on the standard QNET Rotary Pendulum setup. The experimental outcomes indicate that the proposed controller significantly enhances the system’s robustness against exogenous disturbances and maintains its stability within a broad range of operating conditions, without inducing peak servo requirements.
Keywords
Linear quadratic Regulator; adaptive control; degree-of-stability; self-tuning; nonlinear scaling function; rotary inverted pendulum
Hrčak ID:
258419
URI
Publication date:
30.3.2021.
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