A pitch-variable multi-rotor UAV using scissor blades for noise reduction

Abstract

The invention discloses a pitch-variable multi-rotor unmanned aerial vehicle using scissor-type blades for noise reduction, including a frame, a power transmission system, a pitch-variable rotor system, and a flight control system; the power transmission system includes a motor, a first pulley , the second pulley, transmission belt, synchronous pulley and auxiliary shaft; the variable pitch rotor system has four groups, which are distributed at the end of the frame; and each group of variable pitch rotor system includes the main shaft, the first rocker arm, the first Connecting rod, second rocker arm, second connecting rod, slider pitch change ring and propeller hub. The variable-pitch multi-rotor UAV disclosed by the present invention adopts scissor-type blades to reduce noise. The power transmission system uses a motor as the power output, adopts a belt transmission mode, and the transmission terminal is connected to the variable-pitch rotor system. The side multi-link mechanism The first rocker arm is connected to the output end of the steering gear, and the flight control system controls the output of the steering gear to change the collective pitch of the blades through a multi-link mechanism, and quickly and accurately control the change of the lift force by changing the pitch to change the flight attitude.

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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