scholarly journals Control of a Symmetric Chaotic Supply Chain System Using a New Fixed-Time Super-Twisting Sliding Mode Technique Subject to Control Input Limitations

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1257
Author(s):  
Bo Wang ◽  
Hadi Jahanshahi ◽  
Christos Volos ◽  
Stelios Bekiros ◽  
Abdullahi Yusuf ◽  
...  

Control of supply chains with chaotic dynamics is an important, yet daunting challenge because of the limitations and constraints there are in the amplitude of control efforts. In real-world systems, applying control techniques that need a large amplitude signal is impractical. In the literature, there is no study that considers the control of supply chain systems subject to control input limitations. To this end, in the current study, a new control scheme is proposed to tackle this issue. In the designed control input, limitations in control inputs, as well as robustness against uncertainties, are taken into account. The proposed scheme is equipped with a fixed time disturbance observer to eliminate the destructive effects of uncertainties and disturbances. Additionally, the super-twisting sliding mode technique guarantees the fixed-time convergence of the closed-loop system. After that, a symmetric supply chain system is presented, and its chaotic attractors are demonstrated. Finally, the proposed controller is applied to the symmetric supply chain system. Numerical simulations exhibit the proposed scheme’s excellent performance even though the system is subjected to control input limitations and time-varying uncertainties.

Author(s):  
Afef Hfaiedh ◽  
Ahmed Chemori ◽  
Afef Abdelkrim

In this paper, the control problem of a class I of underactuated mechanical systems (UMSs) is addressed. The considered class includes nonlinear UMSs with two degrees of freedom and one control input. Firstly, we propose the design of a robust integral of the sign of the error (RISE) control law, adequate for this special class. Based on a change of coordinates, the dynamics is transformed into a strict-feedback (SF) form. A Lyapunov-based technique is then employed to prove the asymptotic stability of the resulting closed-loop system. Numerical simulation results show the robustness and performance of the original RISE toward parametric uncertainties and disturbance rejection. A comparative study with a conventional sliding mode control reveals a significant robustness improvement with the proposed original RISE controller. However, in real-time experiments, the amplification of the measurement noise is a major problem. It has an impact on the behaviour of the motor and reduces the performance of the system. To deal with this issue, we propose to estimate the velocity using the robust Levant differentiator instead of the numerical derivative. Real-time experiments were performed on the testbed of the inertia wheel inverted pendulum to demonstrate the relevance of the proposed observer-based RISE control scheme. The obtained real-time experimental results and the obtained evaluation indices show clearly a better performance of the proposed observer-based RISE approach compared to the sliding mode and the original RISE controllers.


2021 ◽  
Vol 13 (4) ◽  
pp. 1740
Author(s):  
Cheng Che ◽  
Xiaoguang Zhang ◽  
Yi Chen ◽  
Liangyan Zhao ◽  
Zhihong Zhang

By establishing a two-level symbiotic supply chain system consisting of one supplier and one manufacturer, we use Stackelberg method to analyze the optimal price and revenue model of supplier and manufacturer in the symbiotic supply chain under two power structures in which the supplier and manufacturer are dominant respectively, and analyze the influence of the degree of symbiosis and power structure on the model. Through comparative analysis, we find that: There is a relationship between the income level and the degree of symbiosis in the symbiotic supply chain. The change of power structure will affect the relative benefits of suppliers and manufacturers in the symbiotic supply chain. The manufacturer’s expected unit product revenue will affect the supply chain revenue when the manufacturer is dominant. Finally, the sensitivity analysis of relevant parameters is carried out through an example analysis, and the validity of the conclusion is verified. This paper has a guiding significance for the behavior of enterprises in the cogeneration supply chain.


2006 ◽  
Vol 22 (5-6) ◽  
pp. 557-565 ◽  
Author(s):  
Mustafa Özbayrak ◽  
Theopisti C. Papadopoulou ◽  
Efstratios Samaras

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