System implement of voltage-current dual closed-loop control model of AC-AC matrix converter

Author(s):  
Zhang Shao ◽  
Ge Hongjuan ◽  
Mu Xinhua
Author(s):  
F. Lu ◽  
X. J. Wang ◽  
Y. F. Liu

When ultraviolet light illuminates on polarized PLZT ceramic, a large voltage can be generated between the electrodes due to the anomalous photovoltaic effect. The shape control of flexible shell can be realized by using hybrid photovoltaic/piezoelectric actuation. In this paper, a novel non-contact deflection closed-loop control model of cantilever beam based on hybrid photovoltaic/piezoelectric actuation can be proposed. The photovoltage of PLZT ceramic irradiated by ultraviolet light is applied to drive PVDF actuator. The closed-loop control equations of deflection of cantilever beam is derived based on the mathematical model of PLZT ceramic with coupled multi-physics fields and the constitutive model of cantilever beam. Then, parameters of deflection control equations of cantilever beam during illumination phase and light off phase are identified through the deflection static experiment. After that, the deflection closed-loop control experiment of cantilever beam based on hybrid photovoltaic/piezoelectric actuation mechanism is carried out to verify the control model. The experimental results show that the deflection of cantilever beam with a simple on-off control method can achieve the target value by applying UV light to PLZT ceramic. It also should be noted that, the deflection curve of cantilever beam illuminated by strong UV light has an undesirable fluctuation.


2012 ◽  
Vol 220 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Sandra Sülzenbrück

For the effective use of modern tools, the inherent visuo-motor transformation needs to be mastered. The successful adjustment to and learning of these transformations crucially depends on practice conditions, particularly on the type of visual feedback during practice. Here, a review about empirical research exploring the influence of continuous and terminal visual feedback during practice on the mastery of visuo-motor transformations is provided. Two studies investigating the impact of the type of visual feedback on either direction-dependent visuo-motor gains or the complex visuo-motor transformation of a virtual two-sided lever are presented in more detail. The findings of these studies indicate that the continuous availability of visual feedback supports performance when closed-loop control is possible, but impairs performance when visual input is no longer available. Different approaches to explain these performance differences due to the type of visual feedback during practice are considered. For example, these differences could reflect a process of re-optimization of motor planning in a novel environment or represent effects of the specificity of practice. Furthermore, differences in the allocation of attention during movements with terminal and continuous visual feedback could account for the observed differences.


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