Abstract
This Special Issue on “Fractional-Order Systems: Control Theory, Engineering Applications, and Advances” brings together diverse research contributions highlighting the versatility and effectiveness of fractional-order approaches in control systems and beyond. Below is a summary of the key papers included in this collection:
1. Optimization-based robust fractional-order controllers design for multiple-input single-output systems with time delays Noura Ben Moussa, Manel Chetoui, and Messaoud Amairi present optimization techniques for designing fractional PID controllers for MISO systems with delays. Their methods, rooted in both time- and frequency-domain specifications, showcase robustness and flexibility in tackling control challenges.
2. Design of LQ regulators with prescribed degree of stability for dual-rate systems based on reinforcement learning Vojislav Filipović, Milan Matijević, and Saša Ćuković explore dual-rate systems and propose a novel linear quadratic regulator designed with reinforcement learning. Their work addresses robust stability and dynamic performance in systems with multi-rate sampling constraints.
3. Actuator and sensor fault estimation for T–S fuzzy fractional-order systems based on adaptive and sliding mode observers Slim Dhahri, Omar Naifar, and Essia Ben Alaia propose innovative observer designs to estimate faults in actuators and sensors for uncertain fractional-order nonlinear systems, advancing fault tolerance and robustness.
4. Fractional order second-order sliding mode MRASO for SPMSM Jun-Feng Liu et al. introduce a sliding mode observer based on fractional-order theory to enhance the robustness and accuracy of permanent magnet synchronous motors, particularly in sensorless control systems.
5. Performance evaluation of developed controllers for unmanned aerial vehicles with reference camera Aidana Tassanbi et al. compare PID, fuzzy PID, and pre-filtered fuzzy PID controllers for UAVs, highlighting the effectiveness of fuzzy-based approaches for stable and accurate drone control.
6. Control theory for skewed distribution under operation side of the telecommunication industry and hard-bake process in the semiconductor manufacturing process Azam Zaka et al. propose advanced control charts for handling skewed distributions in the telecommunication and semiconductor industries, offering reliable methods for process monitoring and improvement.
7. Numerical study flow and heat transfer characteristics of superhydrophobic single tube bundle surface and wake flow SD Zhou et al. investigate the effects of superhydrophobic surfaces on heat exchangers, showcasing how slip boundary conditions can reduce flow resistance and enhance heat transfer performance.
Concluding remarks
The articles in this collection emphasize the interdisciplinary applications of fractional-order systems across diverse fields such as energy, robotics, manufacturing, and thermal management. These contributions not only advance theoretical frameworks but also demonstrate practical implementations with significant engineering impact.
Footnotes
Acknowledgements
We thank all contributors for their outstanding work and look forward to seeing these advancements inspire further exploration in fractional-order systems and their applications.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Data availability statement
Data sharing not applicable to this article as no datasets were generated or analyzed during the current study.