Requirements of CNC machine tools for AC servo system

by:V&T Technologies     2020-01-27
Requirements of CNC machine tools for AC servo system servo system is an important part of CNC machine tools. The precision and speed indicators of CNC machine tools are usually determined by the servo system. Servo system has gone through a gradual process from servo to DC servo and then to AC servo system development. With the development of technology, linear drive with high speed and high precision machining has become a new trend in the development of servo system. CNC machine tools need the following points of servo system :(1) Good stability: stability means that the system can reach a new state or return to the original equilibrium state after a short adjustment process under a given input or external interference. (2) High precision of output position: the precision of servo system refers to the precision that the output can follow the input quantity. As a precision machining CNC machine tool, it can pass the required positioning accuracy or contour machining accuracy. Generally, the allowable deviation is usually 0. 01 to 0. Between 00lmm. Statically, high positioning accuracy and repeated positioning accuracy are required, I . e. small positioning error and repeated positioning error (To ensure dimensional accuracy). The following precision is dynamically required, I . e. the following error is small, which is a dynamic performance index (Ensure contour accuracy). In addition, the sensitivity must be high enough to have high resolution. (3) Fast response, fast response and no overshoot: fast response is one of the dynamic quality indexes of servo system, that is, the response of tracking command signal needs to be fast, on the one hand, transition is necessary. The processing time is very short, usually less than 200 milliseconds or even less than tens of milliseconds; On the other hand, in order to meet the overshoot requirement, the leading edge requirement of the transition process is steep, I . e. the increasing rate is very large. This is a requirement for the dynamic performance of the AC servo system, that is, the stabilization time tp of the moving speed of the execution component should be as short as possible without overshoot. The general requirement is from 0 & rarr; Fmax (Fmax & rarr; 0) At the beginning, the time should be 200 MS, and it should not be over-washed, otherwise it is unfavorable to mechanical parts and harmful to processing quality. (4)The speed regulation range should be wide and stable (Within the speed control range). Speed range: General requirements: stability means that the fluctuation of output speed is small, especially at low speed, which is especially important. (5)The load characteristic should be relatively hard. Within the system load range, when the load changes, the output speed should be basically the same. That is, & Delta; F as small as possible. When the load suddenly changes, the recovery time of the required speed is very short and there is no oscillation. That is, & Delta; The shorter the t, the better. In addition, there should be sufficient overload capacity. CNC machine tool servo system must have good static and dynamic rigidity. (6). It can be reversible and often starts and stops. (7). The system has high reliability, convenient maintenance and low cost. To sum up, the requirements of servo system include both static and dynamic characteristics. For high-precision numerical control machine tools, their dynamic performance requirements are more stringent. Tag ac servo system CNC Machine Tool
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