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The problem of fuzzy robust tracking control is investigated for uncertain nonlinear time-delay systems. The nonlinear time-delay system is modeled as fuzzy Takagi-Sugeno (T-S) system, and fuzzy logic systems are used to eliminate the uncertainties of the system. A sufficient condition for the existence of fuzzy controller is given in terms of linear matrix inequalities (LMIs) and adaptive law. Based on Lyapunov stability theorem, the fuzzy control scheme guarantees the desired tracking performance in sense that all the closed-loop signals are uniformly ultimately bounded (UUB). Simulation results of 2-link manipulator demonstrate the effectiveness of the developed control scheme.

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This study investigated the effects of playing soccer on the quality of gross motor skills in preschoolers. A 2-group, pretest-posttest design was adopted, comprising both an experimental and a control group. The participants were recruited from 2 public kindergartens located in New Taipei City, Taiwan. The approval of the legal representatives of the 101 preschoolers enrolled in these kindergartens and aged between 4 years and 6 years and 11 months was obtained, and purposive grouping was subsequently conducted. The experimental group comprised 44 participants from the first kindergarten, whereas the control group comprised 43 participants from the second kindergarten. After the recruitment, the experimental group received a soccer program intervention: a 10-week soccer program with two 40-minute sessions per week. Before and after the experiment, the gross motor quality of both groups was measured using the Preschooler Gross Motor Quality Scale, which covers tests for locomotion, object manipulation, and balance. The results of the 10-week intervention showed significantly higher scores for locomotion, object manipulation, balance, and overall gross motor quality in the experimental group than in the control group. This study confirmed that a 10-week soccer program is beneficial for gross motor development in preschoolers. The research results can serve as a reference for gross motor development in preschool education.

In recent years, 3D overhead crane have been extensively employed in transport industry for the transfer of heavy loads. In order to increase productivity and improve work efficiency, automatic 3D overhead cranes have gained much attention in factories, warehouses, harbors and other environments where there is the need for moving heavy payloads. However, high-speed operation easily results in the large cargo vibrations and swings which can be dangerous and cause damage. Therefore, a high safety control strategy to fast regulate the x-direction, the y-direction and z-direction of the 3D overhead crane is compulsory.Up to now, both classical methods and modern approaches have elicited considerable attention. Classical methods include linear and nonlinear control strategies, adaptive control and optimal control technique. For instance, based on a sliding mode surface and Lyapunov stability theorem, sliding mode control (SMC) [1] is a robust control scheme used to deal with the system uncertainties and external disturbances such that the system stability can be guaranteed. On the other hand, modern approaches comprise command shaping techniques, fuzzy logic control (FLC) [2] and neural network design. For example, various adaptive fuzzy control schemes for approximating arbitrary nonlinear functions have been developed to deal with nonlinear systems whose dynamics are poorly understood. Moreover, an adaptive fuzzy sliding mode controller combines the merits of a sliding mode control, a fuzzy inference mechanism and an adaptive algorithm [3].As we know, the process of sliding mode control is the combination of the approaching phase with and the sliding phase with s(x, t) ≠ 0 and the sliding phase with s(x, t)=0 . Unfortunately, the system invariance properties yielding motion which is independent of unmolded dynamics, parameter uncertainties and external disturbances take place only during the sliding phase. During the approaching phase, the tracking performance can be impeded by the parameter uncertainties and disturbances. In order to achieve fast and robust tracking behavior, a time varying sliding surface is proposed [4] by changing the magnitude of the slope and intercept of the surface. Furthermore, a proportional integral (PI)-type switching structure [5] is incorporated into time varying SMC to attenuate the typical chattering of the switching law.To gather the advantages of the FLC and time varying PI SMC, a novel direct adaptive fuzzy moving sliding mode PI tracking control structure is proposed for a 3D overhead crane system to achieve fast and robust position regulation and anti-swing control [6]. We expect this editorial will provide a study motivation for researchers in both of theoretical investigations and practical applications. References 1. Utkin VI (1997) Variable structure systems with sliding modes. IEEE Trans Automat Control 22: 212-222. 2. Wang LX (1994) Adaptive Fuzzy Systems and Control: design and stability analysis. Prentice-Hall, New Jersey, USA. 3. Chih Lin T (2010) Based on interval type...

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