The serious study of the practice of how to determine the appropriate content of a specification is a seldom-appreciated pastime. Those who have the responsibility to design a product would prefer a greater degree of freedom than permitted by the con- tent of a specification. Many of those who would manage those who would design a product would prefer to allocate all of the project funding and schedule to what they consider more productive labor. These are the attitudes, of course, that doom a project to defeat but they are hard to counter no matter how many times repeated by design engineers and managers. A system engineer who has survived a few of these experiences over a long career may retire and forget the past but we have an endur- ing obligation to work toward changing these attitudes while trying to offer younger system engineers a pathway toward a more sure success in requirements analysis and specification publishing.
标签： Requirements Analysis System
上传时间： 2020-05-31
上传用户：shancjb
In this book for the optimisation of assembly conveyor lines we are dealing with series part production featured by a medium complexity degree and a medium number of individual components and assembly technique alternatives. Modern production techniques for medium to large series products or mass production usually involve assembly conveyor lines. They still use hand labour more or less automated. The aim is to have monotonous and similar in type operations or such causing fatigue, stress and production traumas, gradually replaced by automated assembly cycles, means and techniques. This usually widely involves industrial robots and handlers. Higher productivity, lower cost and higher quality of assembled products are usually required.
上传时间： 2020-06-10
上传用户：shancjb
Abstract: A sliding mode observer and fractional-order phase-locked loop (FO-PLL) method is proposed for the sensorless speed control of a permanent magnet synchronous motor (PMSM).The saturation function is adopted in order to reduce the chattering phenomenon caused by the sliding mode observer. In this proposed FO-PLL, method, a regulable fractional order r is involved, which means that the FO-PLL provides an extra degree of freedom. In fact, the conventional phase-locked loop (PLL) applied in sensorless PMSM control can be seen as a special case of the proposed FO-PLL. By selecting a proper fractional order r a better performance may be achieved. The computer simulation results demonstrate the effectiveness of the proposed method.Key words: fractional calculus; fractional order phase-locked loop; sensorless control; sliding mode observer; permanent magnet synchronous motor; speed controll
上传时间： 2022-06-17
上传用户：pagedown
