Method for designing composite root locus multi-stage PID robust controller for multi-loop model cluster of aircraft

Abstract

The invention provides a method for designing a composite root locus multi-stage PID robust controller for the multi-loop model cluster of an aircraft. The method comprises the following steps of: directly determining to acquire the model cluster composed of amplitude-frequency and phase-frequency characteristics in a full envelope by virtue of a sweep-frequency flight test in different given heights and Mach number conditions; giving a closed-loop pole distribution limit index under the corresponding root locus description according to standard requirements on an amplitude-frequency margin and a phase margin in a flight envelope, determining the stage number and parameter values of the multi-stage PID robust controller by adding the multi-stage PID controller, and by virtue of the closed-loop pole distribution limit index in the full envelope of the aircraft and a model identification method in system identification; and designing the low-altitude flight robust controller meeting the full flight envelope, low in overshoot and stable from the concept of closed-loop pole distribution under the root locus description.

Description

technical field [0001] The invention relates to an aircraft controller design method, in particular to an aircraft multi-loop model cluster compound root locus multi-level PID robust controller design method, which belongs to the categories of measurement and control technology and flight mechanics. Background technique [0002] The control of the take-off and landing process of the aircraft plays an important role in flight safety; due to the large change in flight speed during the take-off and landing process of the aircraft, even according to the longitudinal model, it will face strong nonlinear problems; on the other hand, the control rudder of the aircraft has saturation, dead zones, etc. Phenomenon; From the perspective of flight safety, when flying at ultra-low altitudes (such as aircraft takeoff / landing), the controller must ensure that the system has a certain stability margin, no overshoot and stability, which makes the design of ultra-low-altitude flight controller...

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the technical defect that the existing method cannot design a small overshoot and stable low-altitude flight controller that meets the stability margin index in the full flight envelope when the model of the aircraft varies greatly in the full flight envelope, the present invention Provides a method for designing a multi-loop model cluster compound root locus multi-level PID robust controller for an aircraft. The method directly determines and obtains the amplitude-frequency sum within the full envelope through frequency-sweeping flight tests under the conditions of given different altitudes and Mach numbers. A model cluster composed of phase-frequency characteristics; according to the military standard requirements of amplitude-frequency margin and phase margin within the flight envelope, the closed-loop pole distribution limit index under the description of the corresponding root locus is given. By adding a multi-level PID controller and The closed-loop pole distribution limit index in the full envelope of the aircraft and the model identification method in system identification determine the number of stages and parameter values ​​of the multi-level PID robust controller; starting from the concept of the closed-loop pole distribution limit described by the root locus, a design that meets the full Small overshoot of the flight envelope, stable low-altitude flight controller

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