Hydraulic Multi-Rotor Drone Flow Control for Precise Rotor Speed
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Solution Overview
Problem
Existing drones, particularly those using electric motors, face issues with power variations leading to frequent maintenance, limited flight time, and complex speed control in hydraulic drones, necessitating improvements in weight reduction, control precision, reliability, and responsiveness.
Innovation Solution
A multi-rotor hydraulic drone system utilizing pressurized fluid supplied by a hydraulic pump, with controllable valves to adjust the flow rate of hydraulic motors, allowing precise speed control and improved reliability, and incorporating a flight controller to manage the supply system for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric motors are used for providing lift, then the drone can operate with electrical energy, but the power electronics experience strong current variations leading to frequent maintenance and limited flight time
Solution Approach 1:
The patent replaces electric motors with hydraulic motors to drive the propellers. The hydraulic system uses a pump driven by an electric motor to generate pressurized fluid, which then drives hydraulic motors at each rotor. This substitution eliminates the need for power electronics to handle high current variations directly at the motors, improving reliability while enabling continuous operation for extended flight times.
Solution Approach 2:
The patent implements a hydraulic system where a central pump pressurizes fluid that is distributed to multiple hydraulic motors through controllable valves. This hydraulic architecture allows for smooth power transmission and precise control of motor speed through flow rate modulation, avoiding the current surge issues inherent in direct electric motor control.
2Speed
If hydraulic motors with short-circuit flow control are used, then the rotation speed can be controlled, but power is lost through energy dissipation and speed control precision is impossible
Solution Approach 1:
The patent controls motor rotation speed by varying the flow rate of pressurized fluid to each hydraulic motor through controllable valves, rather than using short-circuit flow control. This parameter change approach allows precise speed control by directly modulating the fluid supply volume, eliminating energy dissipation associated with short-circuiting and enabling accurate speed regulation.
3Speed
If variable displacement hydraulic motors are used, then the rotation speed can be controlled by varying displacement, but the motor design and speed control become complex
Solution Approach 1:
The patent separates the speed control function from the motor displacement. Instead of using variable displacement motors, it employs fixed displacement hydraulic motors where speed control is achieved externally through controllable valves that modulate fluid flow rate to each motor. This segmentation simplifies motor design while maintaining precise speed control capability.
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
The solution enhances the reliability and responsiveness of hydraulic drones by enabling precise control of rotation speed, reducing weight, and extending flight duration, while maintaining a good power-to-weight ratio, thus addressing the limitations of existing drones.
Implementation Method 1
at least one hydraulic pump driven by at least one motor for pressurizing the fluid
Implementation Method 2
with at least one, in particular electrically, controllable valve for at least some of the paths, making it possible to vary a supply flow rate of at least one corresponding hydraulic motor
Implementation Method 3
a plurality of hydraulic motors each receiving a pressurized fluid, propellers driven by the hydraulic motors
Data Source
AI summary
Multi-rotor hydraulic drone (1) comprising: —a plurality of hydraulic motors (6) each receiving a pressurised fluid, —propellers (5) driven by the hydraulic motors (6), —at least one hydraulic pump (10) driven by at least one motor (11) for pressurising the fluid, —a system for supplying the hydraulic motors (6) with pressurised fluid, —a flight controller (14) for controlling the supply system according to the desired rotation speed for the hydraulic motors (6), the supply system comprising several channels (35; 36; 37; 38) for adjusting the power of at least one portion of the hydraulic motors (6).