Fault-tolerant controller design based on adaptive backstepping for tower cranes with actuator faults.

Due to the widespread application and significant investment required for a single crane, there is an increased emphasis on crane safety and service life. Fault-tolerant control as an effective solution to unexpected faults has been widely studied recently. However, most fault-tolerant control methods require redundant actuators or a complex design process, which is unsuitable for the tower crane. Following these problems, a fault-tolerant controller based on an adaptive backstepping technique is proposed. Firstly, the system states are reconstructed and written as a cascade system. Secondly, a fixed-time convergence optimized backstepping controller is proposed to achieve smooth control of the tower crane without generating sudden or abrupt values. Then, an adaptive approach has been proposed to update fault parameters for the crane system in case of a sudden fault occurrence. Finally, after conducting comparison tests, it has been determined that the proposed controller not only performs exceptionally well in terms of position accuracy and swing elimination, but also maintains a satisfactory control performance when faced with sudden faults.

Underlying mechanisms of egg white thinning in hot spring eggs during storage: Weak gel properties and quantitative proteome analysis.

As a weakly gelling protein, hot spring egg white underwent thinning during storage. This study explored the mechanism of thinning in hot spring egg white from the perspective of "gel structure and protein composition" using quantitative proteomics, SEM, SDS-PAGE, and other techniques. Quantitative proteomics analysis showed that there were 81 (44 up-regulated and 21 down-regulated) key proteins related to thinning of hot spring egg white. The changes in the relative abundance of proteins such as ovalbumin-related Y, mucin-6, lysozyme, ovomucoid, and ovotransferrin might be important reasons for thinning in hot spring egg white. SEM results indicated that the gel network gradually became regular and uniform, with large pores appearing on the cross-section and being pierced. Along with the decrease in intermolecular electrostatic repulsion, protein molecules gradually aggregated. The particle size gradually increased from 139.1 nm to 422.5 nm. Meanwhile, the surface hydrophobicity, and disulfide bond content gradually increased. These changes might be the reasons for thinning in hot spring egg white during storage. It can provide a new perspective for studying the thinning mechanism of weakly gelling egg whites.