33 research outputs found

    Global Feed-Forward Adaptive Fuzzy Control of Uncertain MIMO Nonlinear Systems

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    This study proposes a novel adaptive control approach using a feedforward Takagi-Sugeno (TS) fuzzy approximator for a class of highly unknown multi-input multi-output (MIMO) nonlinear plants. First of all, the design concept, namely, feedforward fuzzy approximator (FFA) based control, is introduced to compensate the unknown feedforward terms required during steady state via a forward TS fuzzy system which takes the desired commands as the input variables. Different from the traditional fuzzy approximation approaches, this scheme allows easier implementation and drops the boundedness assumption on fuzzy universal approximation errors. Furthermore, the controller is synthesized to assure either the disturbance attenuation or the attenuation of both disturbances and estimated fuzzy parameter errors or globally asymptotic stable tracking. In addition, all the stability is guaranteed from a feasible gain solution of the derived linear matrix inequality (LMI). Meanwhile, the highly uncertain holonomic constrained systems are taken as applications with either guaranteed robust tracking performances or asymptotic stability in a global sense. It is demonstrated that the proposed adaptive control is easily and straightforwardly extended to the robust TS FFA-based motion/force tracking controller. Finally, two planar robots transporting a common object is taken as an application example to show the expected performance. The comparison between the proposed and traditional adaptive fuzzy control schemes is also performed in numerical simulations. Keywords: Adaptive control; Takagi-Sugeno (TS) fuzzy system; holonomic systems; motion/force control

    Harnessing the power of nutritional antioxidants against adrenal hormone imbalance-associated oxidative stress

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    Oxidative stress, resulting from dysregulation in the secretion of adrenal hormones, represents a major concern in human health. The present review comprehensively examines various categories of endocrine dysregulation within the adrenal glands, encompassing glucocorticoids, mineralocorticoids, and androgens. Additionally, a comprehensive account of adrenal hormone disorders, including adrenal insufficiency, Cushing’s syndrome, and adrenal tumors, is presented, with particular emphasis on their intricate association with oxidative stress. The review also delves into an examination of various nutritional antioxidants, namely vitamin C, vitamin E, carotenoids, selenium, zinc, polyphenols, coenzyme Q10, and probiotics, and elucidates their role in mitigating the adverse effects of oxidative stress arising from imbalances in adrenal hormone levels. In conclusion, harnessing the power of nutritional antioxidants has the potential to help with oxidative stress caused by an imbalance in adrenal hormones. This could lead to new research and therapeutic interventions

    Controllability of spacecraft systems in a central gravitational field

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    Fuzzy Chaotic Synchronization and Communication– Signal Masking and Encryption

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    [[abstract]]In this chapter, we address synthesis approaches for signal synchronization and secure communications of chaotic systems by using LMIbased fuzzy system design methods. Following a general form of TakagiSugeno fuzzy chaotic models, the structure of the response system is firstly proposed. Synthesizing from the observer and controller points of view, two developed drive-response systems achieve asymptotic synchronization. For chaotic communications, the asymptotical recovering of messages is ensured by the same framework. As a further application, a chaotic cryptosystem is proposed. The synchronization design is applied to transmit and decrypt the ciphertext. The combination of both chaotic signal and cyptosystem characteristics achieves communication with a higher level of security. Finally, several well-known chaotic systems are used in numerical simulations and DSP-based experiments.[[booktype]]紙

    LMI-based fuzzy chaotic synchronization and communication

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