A Fractional Model Identification Method of Servo System Considering Delay

Abstract

The invention discloses a servo system fractional-order model identification method considering the delay link, comprising the following steps: establishing a servo system fractional-order model to be identified considering the delay factor; obtaining the frequency domain characteristics of the servo system; constructing a model identification target function ; Calculate the model parameter matrix of the servo system; determine the optimal fractional order, and obtain the fractional order that meets the set threshold; determine the delay link factor. The invention constructs a fractional-order system model with a delay link in the servo system, and uses the frequency domain response data of the system to obtain model parameters, thereby improving the modeling and parameter identification accuracy of the servo system.

Description

technical field [0001] The invention belongs to the technical field of servo control, in particular to a fractional order model identification method of a servo system considering the delay link. Background technique [0002] Servo systems are widely used in advanced intelligent manufacturing fields such as industrial robots and numerical control systems. The motion control performance of the servo system will directly affect the operating efficiency and positioning accuracy of the mechatronics equipment. In order to realize the high-performance motion control of the servo system, precise mathematical modeling is required. [0003] The traditional model identification method first determines the structure of the system model, and then uses the collected data to determine the model parameters through the system excitation of the servo system. The current traditional model identification method has three deficiencies: (1) The mathematical model determined in the traditional ...

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Problems solved by technology

The current traditional model identification method has three deficiencies: (1) The mathematical model determined in the traditional method does not consider the fractional order characteristics existing in the system

In the traditional servo system, the integer-order model is used. The premise is that the inertia and friction of the motor are ideal, that is, the load inertia is evenly distributed, and the friction is strictly proportional to the speed. However, In the actual process, the mass of the load is difficult to distribute evenly, and the friction force cannot be strictly proportional to the speed, which will cause the system to produce fractional-order characteristics; (2) Most of the traditional methods use time-domain signals to identify model parameters, and there is no Determine the model structure and obtain the model parameters from the perspective of the frequency domain; (3) When modeling the servo system in the current data, in order to simplify the model, the delay link is mostly ignored, and the actual servo system cannot be modeled. Accurately described, so the control rate designed based on this model has limited dynamic following performance

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