PMLSM servo system control method based on fractional order hyperbolic tangent switching function

Abstract

The invention discloses a PMLSM servo system control method based on a fractional order hyperbolic tangent switching function. The PMLSM servo system control method comprises the steps of acquiring anerror amount through the subtraction of a given position signal and a feedback position signal of a permanent magnet linear synchronous motor servo system, designing a nonsingular quick terminal sliding mode surface through utilizing the error amount, designing a sliding mode control switching item based on a fractional order hyperbolic tangent switching function, and verifying that the system isstable according to a Lyapunov function. According to the PMLSM servo system control method, the system state can be converged to a stable state within limited time, and the singular problem is avoided. Aiming at the buffeting problem in sliding mode control, a switching law based on the fractional order hyperbolic tangent switching function is introduced into the control method, that is, a new function (time-varying function)-fractional order hyperbolic tangent switching function is used for replacing a traditional sign function. The hardware system comprises a main circuit, a control circuit and a control object.

Description

technical field [0001] The invention relates to the technical field of numerical control machining control, in particular to a PMLSM non-singular fast terminal sliding mode control method based on a fractional order hyperbolic tangent saturation function. Background technique [0002] With the development of society, higher and higher requirements are put forward for high-speed and high-precision CNC machining technology. The feed system of traditional CNC machine tools is mainly in the form of "rotary motor + ball screw". The positive and negative gaps, friction and elastic deformation between the intermediate links of this form increase the nonlinear error of the system, and it is difficult to limit it. High-speed, high-precision technical production requirements. Compared with the traditional rotary motor plus ball screw, the directly driven permanent magnet synchronous linear motor cancels the intermediate transmission device and directly drives the load to move, avoidi...

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Problems solved by technology

[0004] Among these control strategies, sliding mode control has better robustness and better dynamic performance than other methods, but in traditional sliding mode control, the achievable tracking accuracy is relatively low, and it is difficult to meet the high-precision performance requirements, and Traditional sliding mode control usually uses a linear sliding mode surface, which will lead to asymptotic convergence of the system state, and at the same time, the discontinuity of its control effect will lead to chattering

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