The Research Of The Four Rotor Aircraft Height Lock Based On Fuzzy Algorithm

Four rotor aircraft with the advantages of low cost,small size,flexible, easy to operate,has been widely used in recent years, both in the military, civil, and entertainment, and many other occasions can see its shadow. With the widely application of the four rotor aircraft, has attracted more and more aircraft enthusiasts to its research, but because of its complex characteristics of nonlinear, strong coupling, structure characteristics, it is difficult to establish accurate mathematical model for accurate and stable control, according to the different control purpose, many targeted control algorithm is proposed and obtained the certain achievement.The research mainly aims at the height of the four rotor aircraft locking control, fuzzy control algorithm is proposed.Generated off-line through the establishment of the fuzzy controller and fuzzy control rule table, realize four rotor aircraft height locking online control.The fuzzy controller based on the actual height and the actual height of the vehicle and lock the height of the height difference as input of fuzzy controller, with double input and single output fuzzy controller structure, the use of manual operation in the process of vehicle height locking experts experience to generate a series of language control rules, the fuzzy control system generated by the MATLAB fuzzy control toolbox, after simulation operation to generate the fuzzy control system of the input and output, then the input and output quantity loaded into the query system prepared ahead of time, at the last Generated after to blur control rules table. The generated fuzzy control rules table loaded into the aircraft control system to realize on-line control. Due to the fuzzy control in building the language rules and the subjectivity of determining fuzzy set membership function parameters and the fuzzy control rules table may not accurately reflect the actual state of flight of the aircraft system, so the paper the use of a large number of experimental data using the gradient descent method for the parameters of membership function in fuzzy control system are optimized, make its can accurately reflect the actual state of the aircraft system.Gradient descent method is proved by experiments and the optimized parameters ofmembership function can more accurately reflect the status of aircraft flight, this topic research the aircraft height locking control achieved good effect.