Variable-pitch multi-rotor unmanned aerial vehicle adopting scissor type blades for noise reduction

Abstract

The invention discloses a variable-pitch multi-rotor unmanned aerial vehicle adopting scissor type blades for noise reduction. The variable-pitch multi-rotor unmanned aerial vehicle comprises a rack, a power transmission system, a variable-pitch rotor system and a flight control system. The power transmission system comprises a motor, a first belt pulley, a second belt pulley, a transmission belt, a synchronous pulley and an auxiliary shaft; the four groups of variable-pitch rotor systems are distributed at the end part of the rack; each variable-pitch rotor system comprises a main shaft, a first rocker arm, a first connecting rod, a second rocker arm, a second connecting rod, a sliding block variable-pitch ring and a propeller hub. According to the variable-pitch multi-rotor unmanned aerial vehicle adopting the scissor type blades for noise reduction, a power transmission system outputs power through a motor, a belt transmission mode is adopted, a transmission terminal is connected with a variable-pitch rotor system, a first rocker arm of a side multi-connecting-rod mechanism is connected with the output end of a steering engine, and a second rocker arm of a side multi-connecting-rod mechanism is connected with the output end of the steering engine; the flight control system controls output of a steering engine, the total pitch of blades is changed through a multi-connecting-rod mechanism, and the change of lift force is rapidly and accurately controlled by changing the pitch, so that the flight attitude is changed.

Description

technical field [0001] The present invention relates to the technical field of unmanned aerial vehicles, and more specifically relates to a pitch-variable multi-rotor unmanned aerial vehicle that adopts scissor-type blades for noise reduction. Background technique [0002] At present, the attitude control of quadrotor aircraft mainly adopts the method of changing the speed of the blades, and is mainly divided into odd-numbered axes and even-numbered axes. Due to the use of variable speed control methods, fixed-pitch blades are used on the axes. The flight states of the aircraft such as take-off, forward flight and hovering can be realized by changing the relative rotational speed of the four blades. [0003] But, existing quadrotor aircraft has following shortcoming: [0004] First, the flight control system is complicated: the speed change requires a long response time, and there will be obvious overshoot during the adjustment process, and it will recover after deviating f...

AI Technical Summary

Problems solved by technology

[0004] First, the flight control system is complicated: the speed change requires a long response time, and there will be obvious overshoot during the adjustment process, and it will recover after deviating from the target flight state, so it is necessary to complete the precise flight attitude under the same flight conditions Regulation requires a very complex flight control program and hardware guarantees such as high-precision motors;

[0005] Second, the load capacity is limited: because it uses fixed-pitch blades, it can only guarantee the best lift in a certain flight state. When it deviates from this state, the lift will decrease and affect normal flight. Therefore, if you want to increase Large load capacity can only increase the number of rotors, and this will increase the structural weight at the same time, reduce the increase in load capacity, and eventually reach a saturation, and the load capacity cannot break through the limit;

[0006] Third, the flight attitude is limited: the fixed-pitch blade only maintains the best efficiency under one working condition. When its attitude changes greatly (the inclination angle is close to 90 degrees), the lift of the propeller is not enough to stabilize the attitude. Therefore, the existing four-rotor can only complete the stable attitude flight under the condition of forward flight and small inclination angle, and cannot complete continuous sideways flight or even inverted flight;

[0007] Fourth, the utilization rate of the motor is not high. Due to the need to change the attitude of the speed control, the motor must ensure that the power is sufficient to complete such control

Therefore, in the working state, the power of the motor cannot be fully utilized, and the efficiency of use is limited.

[0008] Fifth, due to the difference in working conditions between the variable-pitch blades and the fixed-pitch blades of the existing variable-pitch multi-rotor aircraft, the variable-pitch blades can achieve optimal blade efficiency under various working conditions, so that As a result, under the same load, compared with the optimal fixed-pitch blade under specific working conditions, the rotational speed is higher, and its basic noise is larger than that of ordinary quadrotors

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