Four-rotor flight control method based on fractional order saturation function power switching law

Abstract

The invention discloses a four-rotor flight control method based on the fractional order saturation function power switching law. A system is split into two subsystems through utilizing the backstepping control method, the traditional backstepping control method and the sliding mode control method are utilized to design sub-control laws satisfying the Lyapunov theorem for the two subsystems, specifically, the backstepping control method is to inherit integrity and unity, and the sliding mode control method is to improve robustness and the anti-interference ability. When the sliding mode control method is utilized, the fractional order saturation function power switching law is introduced to improve performance of a controller, trembling is suppressed, fast response of the flight control ofa four-rotor drone is guaranteed, through adjusting saturation function parameters, nonlinear characteristics of the controller can be further improved, trembling in controller output is filtered, and smoothness of the controller is improved.

Description

technical field [0001] The invention belongs to the technical field of four-rotor unmanned aerial vehicles, and more specifically relates to a flight control method for four-rotor unmanned aerial vehicles based on a power switching law of a fractional saturation function. Background technique [0002] With the increasing demand for intelligent equipment and the rapid development of aerospace technology, drones have entered people's lives from the initial military and production activities. Among them, the four-rotor UAV is simple in structure, flexible in flight, and low in cost. It is favored by ordinary people and meets the consumption level of ordinary families. Moreover, the quadrotor UAV has the function of vertical take-off and landing, which greatly reduces the strict requirements of the aircraft for take-off and landing. Therefore, the quadrotor UAV has become a hot spot in the field of UAV research, attracting the attention of a large number of scientific researche...

AI Technical Summary

Problems solved by technology

[0003] The quadrotor UAV is an underactuated nonlinear system. Although the mechanical structure is relatively simple, the control method is relatively complicated due to the strong coupling between the state variables and the fixed output direction of the power system.

However, each control method must have a bottleneck that limits its further improvement. For example, in the patent "Flight Control Method of Quadrotor UAV Based on Fractional Power Switching Law" (Patent No.: 201711430426.0), although the fractional calculus theory The introduction makes the control speed of the controller faster, but as the fractional order parameter in the controller becomes larger, the output of the controller will tremble

The root of this tremor is the sign function of the sliding mode control method, but the fractional order parameters will amplify it, which will cause a great burden on the controller, produce negative effects that cannot be ignored, and affect the stability of the controller

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