Dual-Rotor UAV Thrust Control for Payload and Yaw Stability

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Solution Overview

Problem

Unmanned aerial vehicles face limitations in maximum payload capacity and flight duration, particularly in agricultural applications.

Innovation Solution

The unmanned aerial vehicle is equipped with a combination of first and second rotors, where the control device adjusts the rotational speed and thrust of the second rotors to enhance payload and flight duration by optimizing thrust distribution during yaw control and attitude adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the total thrust of second rotors is maintained high during rudder control, then payload capacity is improved, but yaw angle control precision deteriorates due to control delay and oscillation

Engineering Contradiction:
Improvepayload capacityVSAvoidyaw angle control precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the thrust contribution of second rotors variable rather than fixed. The control device dynamically adjusts the thrust of second rotors based on flight conditions: during normal flight, second rotors provide main thrust for payload capacity; during rudder control, their thrust is reduced to eliminate control delay and oscillation, improving yaw angle control precision. This dynamic adjustment resolves the contradiction between maintaining high payload capacity and achieving precise yaw control.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of thrust distribution between first and second rotors based on operational mode. By adjusting the rotational speed and thrust output of second rotors according to whether the vehicle is in normal flight or rudder control mode, the system optimizes both payload capacity and control precision. This parameter change allows the same hardware configuration to satisfy contradictory requirements under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If rotational speed of second rotors is increased to increase payload capacity, then power consumption increases, but flight duration decreases

Engineering Contradiction:
Improvepayload capacityVSAvoidflight duration
Core Design Contradiction:
Quantity of substanceVSDuration of action of moving object

Solution Approach 1:

The patent segments the thrust generation function between two types of rotors: first rotors optimized for efficient cruising and long-duration flight, and second rotors optimized for high-thrust operations. By dividing the overall thrust requirement into contributions from both rotor types, the system can maintain high payload capacity when needed while relying on efficient first rotors during normal flight, thereby extending flight duration without sacrificing payload capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs periodic action by alternating between different thrust distribution modes. During normal flight phases, the system uses a thrust distribution that prioritizes efficiency and extends flight duration. When payload capacity needs to be maximized, the system periodically switches to a mode where second rotors contribute more thrust. This periodic switching between operational modes allows the vehicle to achieve both long flight duration and high payload capacity at different times during the mission.

Inventive Principle:
Principle #19Periodic action

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 allows for increased payload capacity and extended flight time, enabling a wider range of agricultural operations such as large-scale agricultural chemical spraying and crop monitoring.

Implementation Method 1

A rotary-wing type unmanned aerial vehicle is a UAV that generates lift using propellers, namely rotary wings, which rotate around an axis

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

performing attitude control by controlling rotation of the plurality of first rotors, and generates a main thrust by controlling rotation of the plurality of second rotors

Methodology Applied
Scientific EffectAngular momentum: Angular Momentum

Data Source

PatentEP4620837A1Unmanned aerial vehicle, and control system and control method for unmanned aerial vehicle
Publication Date: 2025.09.24 KUBOTA CORP
  • EP4620837A1 patent drawingFigure 1A
  • EP4620837A1 patent drawingFigure 1B
  • EP4620837A1 patent drawingFigure 1C

AI summary

An unmanned aerial vehicle includes: a plurality of rotors including a plurality of first rotors and at least one second rotor; and a control device to perform attitude control of the body of the vehicle by controlling rotation of the plurality of first rotors, and generate a main thrust by controlling rotation of the at least one second rotor. The control device calculates a first thrust that is a total thrust to be generated by the plurality of first rotors, and calculates a second thrust that is a total thrust to be generated by the at least one second rotor, based on the first thrust and the total thrust needed for flight; determines a rotational speed of each of the plurality of first rotors based on the first thrust; and determines a rotational speed of the at least one second rotor based on the second thrust.