UAV Center Frame Motor Relocation for Stability
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Solution Overview
Problem
The stability and agility of multi-copters are compromised due to the increased weight of the leading end portion of their arms, particularly when equipped with variable pitch mechanisms, which affects their posture control and flight performance.
Innovation Solution
The design relocates motors to the center frame, using a drive shaft with a bevel gear to transmit power to the rotors, reducing the weight at the arm's leading end and incorporating a pitch changing mechanism that adjusts all rotors' pitch angles simultaneously, maintaining identical angles to enhance stability and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If motors and pitch changing mechanisms are provided at the leading end portion of each arm, then the rotor can be directly driven, but the weight of the leading end portion increases, deteriorating stability and agility of flight motions
Solution Approach 1:
The motor is extracted from the leading end portion of the arm and relocated to the center frame. This separation removes the heavy motor and pitch changing mechanism from the arm's leading end, significantly reducing its weight. The motor remains functionally connected to the rotor through a transmission system (drive shaft and bevel gear), maintaining direct drive capability while eliminating the weight penalty at the critical leading end position.
2Power
If a toothed belt is employed as a motive power transmission member, then power can be transmitted from motor to rotor, but the output shaft must stand perpendicularly in the center frame, degrading spatial efficiency
Solution Approach 1:
Instead of using a toothed belt that requires perpendicular shaft orientation, the invention inverts the transmission approach by using a drive shaft with bevel gears. This allows the motor's output shaft to point toward the arm (horizontal orientation) rather than standing perpendicularly, completely inverting the spatial arrangement and achieving superior spatial efficiency in the center frame while maintaining effective power transmission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration improves the stability and agility of multi-copters by reducing the weight and complexity of the arm structure, allowing for efficient control of flight motions and energy management, while maintaining the benefits of variable pitch without the need for propeller replacement.
Implementation Method 1
a leading end portion of the drive shaft is connected, via a bevel gear, to a base end portion of a rotor shaft that is a rotation shaft of the rotor
Data Source
AI summary
To provide an unmanned aerial vehicle that eliminates or minimizes the laboriousness involved in optimal pitch adjustment of propellers while eliminating or minimizing complexity and instability in airframe structure and/or flight programs. This object is solved by an unmanned aerial vehicle that is provided with a plurality of rotors and that includes: a center frame that is a central portion of an airframe of the unmanned aerial vehicle; and a plurality of arms extending radially from the center frame in plan view. A plurality of motors that are driving sources of the respective rotors are provided in the center frame. The plurality of rotors are supported by the respective arms. Each arm of the arms has a hollow cylindrical structure. A motive power transmission member configured to transmit a driving force of each motor of the motors to the each rotor is provided in the each arm.