Variable gain-based supercoiled sliding mode control method

Abstract

The invention discloses a variable gain-based supercoiled sliding mode control method, and the variable gain-based supercoiled sliding mode control method is mainly applied to control of multi-axis systems such as a mechanical arm. The power item gain in a general supercoiled algorithm is redesigned to be variable gain, the newly increased gain is used as output of a first-order system, an absolute value of a sliding mode function is increased in proportion, the function after amplitude limiting is used as an input signal of the first-order system, and the violent change degree of the input signal is smoothed by using the low-pass filtering characteristic. The newly increased gain has the following advantages that when the system state track is farthest from a sliding mode switching surface, the variable gain is increased to a maximum value, so that a controller accelerates the system state track to approach the sliding mode switching surface with the maximum force; and when the systemstate is in a quasi-sliding mode, the variable gain is attenuated to a minimum value, so that the controller fully inhibits the motion amplitude of the system state track by taking the sliding mode switching surface as the center so as to inhibit control input jitter of the system.

Description

technical field [0001] The invention relates to a superhelical sliding mode control method based on variable gain, which is mainly applied to the control of multi-axis systems such as mechanical arms, and belongs to the technical field of nonlinear control. Background technique [0002] The excellent robustness of sliding mode control makes it widely used in practice, such as the speed control of permanent magnet synchronous motors; the position tracking control of multi-axis manipulators; the attitude control of UAVs, etc. Generally, the design of the sliding mode controller can be divided into two stages, namely, the design of the sliding mode function and the design of the reaching rate. The sliding mode function mainly affects the dynamic performance of the system in the sliding mode stage, while the approach rate mainly affects the performance of the system in the sliding mode arrival stage. A system that is strictly in the sliding mode is very robust to external distu...

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Problems solved by technology

Therefore, the greater the absolute value of the approach rate at this time, the greater the range of motion of the system state trajectory centered on the sliding mode switching surface, which will affect the robustness and aggravate the chattering of the control input

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