Nonlinear modeling method and trimming method for composite rotor aircraft

Abstract

The invention discloses a nonlinear modeling method and a linear trimming method for a composite rotor aircraft, and belongs to the technical field of control of composite rotor aircrafts. According to the method, the aerodynamic characteristics of all parts are analyzed, and a split modeling method is adopted to carry out dynamic modeling; on the basis of the model, combined with a quasi-Newton iteration method and a sequence quadratic programming method, a quasi-Newton-sequence quadratic programming method is proposed to dynamically balance the dynamic model of the composite rotor aircraft and make small disturbance linearity at the equilibrium point, so that an approximate linearized kinetic equation for the equilibrium point can be obtained. The dynamic model established by using the modeling method disclosed by the invention is high in confidence coefficient and simple in calculation, in addition, the new trimming method provided by the invention can avoid solving the inverse matrix of the objective function Hessian matrix, the calculation is simplified, the relatively high convergence speed is ensured, and the method can be used for researching the control method of the composite rotor aircraft.

Description

technical field [0001] The invention belongs to the technical field of flight mechanics and flight simulation, and in particular relates to a nonlinear modeling method and a linearized trimming method of a composite rotorcraft. Background technique [0002] The composite rotorcraft has a thrust device, a fixed wing and a rotor at the same time, which can not only realize the vertical take-off and landing, hovering flight of the helicopter flight mode, but also have the high speed, long range and long endurance flight capability of the fixed wing aircraft, and has been highly regarded. Helicopter research institutions and researchers around the world are concerned. At present, the research on the compound rotorcraft carrier-based UAV is still in its infancy at home and abroad. Due to technical confidentiality and other reasons, there are few published documents in this field. [0003] As the basis of the control method, it is not easy to establish the mathematical model of t...

AI Technical Summary

Problems solved by technology

Among them, mechanism modeling requires an in-depth understanding of the aerodynamics of the model, and the workload and difficulty are relatively large; system identification can avoid the decomposition and measurement of the model, the complexity is low, and the model is easy to build, but it loses the nonlinear characteristics of the dynamics. It is only suitable for modeling at specific working points; and wind tunnel tests also have high requirements for test models

In addition, for the convenience of controller design, the Newton iteration method and quasi-Newton iteration method are usually used at home and abroad to analyze the dynamic trim and small disturbance of the aircraft equilibrium point, but the Newton iteration method needs to obtain the Hessian matrix of the objective function. When the system model is complex , when the Hessian matrix cannot be obtained or the Hessian matrix is ​​singular, the algorithm cannot be carried out; while the quasi-Newton iterative method uses the approximate matrix of the Hessian matrix instead of the Hessian matrix, and at the same time ensures a better convergence speed, but it cannot control the rudder surface. Aircraft dynamics model for trimming

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