Model-free control method for aerodynamic heat superhelix nonlinear fractional order sliding mode

Abstract

The invention discloses a model-free control method for an aerodynamic heat superhelix nonlinear fractional order sliding mode, and the method comprises the steps: building a mathematical model between the input electric energy and the output temperature of an aerodynamic heat ground simulation system of a hypersonic aircraft based on the law of conservation of energy, and converting the mathematical model into a model-free control superlocal model; constructing a nonlinear fractional order sliding mode surface according to the defined output tracking error, the nonlinear function and the fractional order calculus; and in combination with the nonlinear fractional order sliding mode surface, the super-spiral approaching rate, the super-local model and a time delay observer, a model-free controller of the super-spiral nonlinear fractional order sliding mode is built, and buffeting in the control process is suppressed. According to the design of the nonlinear fractional order sliding mode surface, the stability of control is ensured, the convergence speed is high, the steady-state error and the saturation error are reduced, and the shaking problem of the sliding mode surface is improved through the combination of the super-spiral approaching rate.

Description

technical field [0001] The invention relates to the technical field of aerospace automation, in particular to an aerothermal superhelical nonlinear fractional-order sliding mode model-free control method. Background technique [0002] Common ground simulation thermal tests for structural thermal experiments mainly include wind tunnel tests and radiant heat tests. Wind tunnel tests are expensive and require harsh environmental conditions. The thermal environment of the aircraft cannot be accurately simulated at too high a flight Mach number, while radiation The thermal test transfers thermal energy to the test piece in non-contact ways such as convection, conduction, and radiation, effectively simulating the sequential heating of the test piece during flight; among them, because the quartz lamp has a fast heating speed, small size structure, large output power, The characteristics of safe operation, so the quartz lamp heater with tungsten wire as the heat radiation element is...

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Problems solved by technology

[0003] Considering that there are some unknown dynamic disturbances in the process control of quartz lamp heaters, a hyperlocal model method of model-free control is proposed. The hyperlocal model of model-free control requires that the controlled object is a single-input and single-output system, and is controlled by The mathematical expression of the control object can only be a first-order or second-order system. As an indispensable branch of modern control theory, sliding mode control has the characteristics of fast response, simple structure and insensitivity to disturbance compared with traditional control methods. However, due to the strict requirements on convergence speed and control accuracy, some control algorithms combined with sliding mode have been widely proposed; fractional-order sliding mode control not only has the advantages of traditional sliding mode control, but also has strong Robustness and flexibility, but the existing linear fractional-order sliding mode has the disadvantages of not being able to reduce the jitter phenomenon and low control accuracy, and cannot meet the requirements of the high-performance index of the controlled object

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