Vector control has been widely used in control of permanent magnet synchronous motors (PMSM) where the rotor position information is required. The cost of mechanical sensors and the difficulty to incorporate them make it necessary to avoid their uses and to study the mechanical Sensorless control. The idea behind such methods is to extract the motor position and speed information in functions of the terminal quantities from the motor equations. There are many methods which vary in principle and observer structure. In this paper some most promising methods are classified for different application conditions.
Significance
We study microvilli of
Caenorhabditis elegans
larvae and mouse intestinal tissues by combining high-pressure freezing, cryo-focused ion-beam milling, cryo-electron tomography, and subtomogram averaging. We find that many radial nanometer bristles, referred to as nanobristles, project from the lateral surface of nematode and mouse microvilli. The
C. elegans
nanobristles are 37.5 nm long. We show that nanobristle formation requires a protocadherin family protein, CDH-8, in
C. elegans
. The loss of nanobristles in cdh-8 mutants slows down animal growth and ectopically increases the number of Y-shaped microvilli, the putative intermediate structures if microvilli split from their tips. Our results reveal a potential role of nanobristles in separating microvilli and suggest that microvilli division may help generate nascent microvilli with uniformity.
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