Study Of Error Control Technology For High Performance CNC System

High-speed high accuracy motion control is recognized as one of the most important areas in manufacturing, which is the kernel technique in high-speed machining center playing an important role in increasing the productivity and quality of manufacturing. Disturbance, nonlinearities, model and parameter's un-match are factors which induce blunders in high performance CNC (Computer Numerical Control) system. This dissertation researches the high motion control algorithms'implementation on the CNC system. Researches blunder avoiding and blunder compensation through single-axle control and max-axles coupling control.In actual applications, servo systems not only asked to have perfect tracing performance but also need to have good anti-interference performance which is hard for single-freedom controller. CNC systems have high requirements for above two aspects so it need two-freedom controller which can independently adjust tracing parameters and disturbance parameters. This dissertation researches two-freedom controller based on PID algorithm and improved inner model theory.Control system's single feedback structure is hard to meet actual projects, so a new control structure feed-forward mostly appears in actual projects as the form of single or combined with feedback. This dissertation firstly research servo control system's triple structure, then combines with feed-forward system and put forward a feed-forward compensation model which based on friction model and cutting resistance forecasting model.In synchronism and max-axles-coordination control domain contour error is more important than tracing error. This dissertation discusses the relationship between motion tracing system's gain and contour error through simple model of position servo system. Analyzing quantify relationship between tracing error and contour error, relationship between axle-character and contour error and giving some conclusions. At last, this dissertation designs a solve-scheme which based on Fuzzy control for contour error.In order to meet the requirement of actual requirement and also as the carrier of author's subject matter, this dissertation designs a motion control card which based on DSP. There is a CPLD encoder feedback circuit which breaks through DSP chip's limit, on the card. Speed detection algorithm, input signal's smoothing filter and notch filter are designed which can smooth disturb component, improving input signal's qualitative, assurance inner control algorithm's effective account. In addition, electromagnetism problem was discussed during hardware design procedure.