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Aiming at the cooperative control problem of multi-agent system, the fixed-time containment control of general second-order multi-agent system under mismatched disturbances is studied. Firstly, the problem of multi-agent system fixed-time containment control in ideal state is analyzed, and a distributed control protocol based on variable structure control is proposed. Then, a nonlinear fixed-time disturbance observer is designed, aiming at the mismatched disturbance, and a fixed-time control protocol based on the nonlinear disturbance observer is proposed. Finally, the effectiveness of the proposed control protocol under switching topology and multi-source disturbance is verified by numerical simulation.

This paper investigates a robust detection for demagnetization fault in the permanent-magnet synchronous motor (PMSM). A proportional-integral fading sliding-mode observer (PIFSMO) is proposed, which can solve the problem of PMSM performance degradation caused by the permanent-magnet demagnetization and resistance disturbance increase during long-term operation. A PMSM demagnetization model is established, and an improved PIFSMO is proposed to detect the demagnetization flux linkage. A fading integral term is added to the traditional sliding-mode observer, which can suppress the offset in the resistance disturbance estimation caused by transients, thereby achieving direct estimation of the resistance disturbance and the slowly varying resistance disturbance (e.g., ḋ≠0) in particular. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposal. [ABSTRACT FROM AUTHOR]

To address the problem of demagnetization fault diagnosis of permanent magnet synchronous motor (PMSM) under inductance change, a demagnetization fault detection method based on an adaptive observer is proposed. First, the mathematical model of the demagnetization fault of PMSM in a synchronous rotating coordinate system is established, and the inductance disturbance is analyzed separately. Then, considering the different characteristics of the flux linkage fault and inductance disturbance, a new adaptive observer is proposed. Two adaptive laws are designed to ensure the accuracy of fault diagnosis and to eliminate the influence of inductance disturbance, thus achieving the robust diagnosis of demagnetization fault. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate the clinical efficacy of ultrasonic emulsification plus IOL implantation in patients with primary angle-closure glaucoma and cataract., Methods: The clinical data of 81 patients (91 eyes) with primary angle-closure glaucoma comorbid with cataract in our hospital were retrospectively analyzed and divided into two groups based on surgical modality. Group A (n=40, 45 eyes) underwent trabeculectomy and group B (n=41, 46 eyes) underwent ultrasonic emulsification and IOL implantation. The success rate, best corrected visual acuity, intraocular pressure, anterior chamber depth, anterior chamber angle, visual field, cornea's endothelial cell count, complications, and patient satisfaction were compared between the two groups., Results: The surgical success rate in group B was 97.83%, significantly higher than 86.67% in group A ( P < 0.05); Compared with group A, group B had higher best-corrected visual acuity and lower intraocular pressure ( P < 0.05) as well as higher central and peripheral anterior chamber depths at 3 months postoperatively ( P < 0.05); After surgery, group A had significantly lower postoperative cornea's endothelial cell count ( P < 0.05). Compared with group A, MS was higher and MD was lower in group B at 3 months postoperatively ( P < 0.05); the complication rate in group B was 8.70%, lower than 28.89% in group A ( P < 0.05)., Conclusion: The clinical efficacy of ultrasonic emulsification combined with IOL implantation is remarkable in patients with primary angle-closure glaucoma and cataract, which is conducive to improving postoperative visual acuity, lowering intraocular pressure, increasing the atrial angle, and improving visual field defects. It is also with high safety, but has little effect on cornea's endothelial cell count., Competing Interests: None., (AJTR Copyright © 2021.)