A Control Method for Air Vehicle Free Flight in Wind Tunnel Based on Nonlinear Control Law

Abstract

The invention discloses an aircraft wind tunnel free-flight control method based on a nonlinear control law. The method comprises the steps of building a flight dynamics equation according to aircrafttest system data of a horizontal wind tunnel; converting the flight dynamics equation into a state space equation; dividing an aircraft control system into an inner ring rotation control loop and anouter ring mass center control loop through a time scale separation theory; for the inner ring rotation control loop, designing the control law by an INDI incremental dynamic inversion method or an NDI dynamic inversion method; for the outer ring mass center control loop, according to wind tunnel dynamic test data, adding dynamic derivative influence terms to design the control law; and controlling the rudder surfaces of an aircraft through the inner ring rotation control loop and the outer ring mass center control loop. According to the method, the system nonlinearity can be effectively counteracted; the interference can be reduced; the required control requirements are met and the control effect is optimized; and the control precision is improved.

Description

technical field [0001] The invention belongs to the field of wind tunnel model flight experiments, in particular to a control method for free flight in a wind tunnel of an aircraft based on a nonlinear control law. Background technique [0002] The horizontal wind tunnel model free flight test was first developed by the NASA Langley Research Center (NASA Langley Research), and has been used to study the high angle of attack stall / Deviation characteristics and flight control issues. In 2008, Germany's RWTHAachen University carried out system identification research using a horizontal wind tunnel model free flight test; Japan's Tokai University and Kyushu University have also conducted research based on Exploration of flight mechanics characteristics of wind tunnel free flight test. From the perspective of test risk, test efficiency, and controllability and repeatability of the test environment, the free flight test of the horizontal wind tunnel model has become an importan...

AI Technical Summary

Problems solved by technology

[0003] However, there are the following problems in the existing control technology for the free flight of the aircraft wind tunnel: 1. The rudder surface of the aircraft is redundant, resulting in the actual rotation control loop, the output vector dimension is greater than the input vector, that is, the rudder surface instruction that meets the conditions mathematically is not unique, This involves an optimization problem, also known as the rudder assignment problem

2. If a thrust vectoring device is installed on the aircraft, for the thrust vectoring rudder surface and the aerodynamic rudder surface, the frequency bandwidth of the actuator is different, and the difference in rudder effect is large, and the steering of the thrust device will also pay a large thrust loss; Therefore, the two rudder surfaces need to design a suitable fusion control method

3. For an aircraft with a novel layout, if its aerodynamic rudder surface contains canards, it will make the flight control law design more complicated

The whole process is cumbersome and complicated, difficult to implement, and long design cycle

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