Tool Servo System Driven By Maxwell Force

With the development of technology, there exists increasing needs in ultra-precision machining area, especially the free-form surface components, and at the same time the requirement for the components'surface quality is higher. Single-point diamond turning method is widely used to process free-form surface parts, but the existing tool servo systems have the low-frequency response problem. There is an urgent need to develop fast tool servo technology. This paper introduces the processing methods of free-form surface parts at first, summarizes the research developments of several kinds of fast tool servo, and proves the fast tool servo system driven by Maxwell force can realize high frequency response.This paper discusses the theoretic analysis of the Maxwell force tool servo system, mechanical structure design, driver design, controller design and control algorithm. The thesis focuses the research work on the following aspects:1. Based on the designing theory of magnetic circuit, the paper analyzes magnetic circuit model of Maxwell force fast tool servo system, infers model driving formula and indicates the linear relationship between model driving electric current and displacement.2. For the sake of designing appropriate mechanic system, this paper uses FEM theory to analyze the distribution of static magnetic field, high frequency magnetic field, driving force and eddy current loss.3. This paper adopts four-parallel circuit as the driver, and makes use of noise-compensating-capacitive-loads method to limit the bandwidth of the amplifier circuit to be 0-100kHz. Driver's continuous current can reach 5A and the DC's and AC's linearity are both perfect, which fit for driving servo tool.4. According to the result of open-loop test, the writer designs a controller which contains AD, DA and SCM, and controlled by PID calculating method.In theory the peak acceleration of the designed Maxwell force tool servo mechanism can reach 1000G, the open-loop driving response frequency can reach 100kHz or higher. When in the 0-45kHz region, the linearity is good. The maximum displacement of mechanism can reach 15.25μm. The whole system can trace 500Hz sine curve with zero phase-difference.