Multicopter Yaw Control Using Pitch and Attitude Propeller Torque

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Solution Overview

Problem

Multicopters face difficulties in fine control during yaw rotation due to large torque generated by the main rotor, making it challenging to operate them effectively, especially when trying to maintain a steady position for tasks like camera shooting or inspection.

Innovation Solution

The aircraft incorporates a control circuit with both a first yaw rotation generation control unit for managing torque from propeller pitch adjustments and a second yaw rotation generation control unit for controlling torque differences from attitude control propeller speed variations, allowing for enhanced operability during yaw rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a variable pitch mechanism is used to control yaw rotation with the engine, then yaw rotation can be achieved, but fine output control within a small output range becomes difficult without a highly-accurate and highly-rigid link mechanism

Engineering Contradiction:
Improvefine output controlVSAvoidlink mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The yaw rotation control is segmented into two independent systems: (1) a first yaw rotation generation control unit that controls torque from main propellers via pitch adjustment for coarse yaw control, and (2) a second yaw rotation generation control unit that controls torque from attitude control propellers for fine yaw control. This segmentation allows each subsystem to operate within optimal torque ranges, eliminating the need for highly-accurate link mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Attitude control propellers serve as intermediary elements that generate additional torque to supplement or fine-tune the yaw rotation control. By introducing these intermediate torque sources, the system achieves fine control capability without requiring the main engine's variable pitch mechanism to operate in its less controllable small output range.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If attitude control motor is used for yaw rotation by giving speed difference, then yaw rotation control can be performed, but the motor output is relatively small and the motor can only rotate at a lower speed than the engine

Engineering Contradiction:
Improveyaw rotation controlVSAvoidrotation speed
Core Design Contradiction:
Ease of operationVSSpeed

Solution Approach 1:

The system merges two torque generation methods into a unified yaw control system: torque from main propellers (first yaw rotation generation) and torque from attitude control propellers (second yaw rotation generation). The control circuit combines both torque sources to achieve the desired yaw rotation, allowing the system to leverage the high-speed capability of the engine while using the motor for fine adjustments.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If a highly-accurate and highly-rigid link mechanism is used for fine yaw control, then fine output control can be achieved, but it is not realistic to mount such a mechanism on a multicopter

Engineering Contradiction:
Improvefine output controlVSAvoidlink mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the need for a highly-accurate mechanical link mechanism with an electrical control system. The control circuit electronically manages two torque generation methods, substituting complex mechanical precision requirements with electronic control capabilities that are more practical for multicopter applications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Force

If the engine generates large yaw rotation torque, then yaw rotation can be achieved, but fine control becomes difficult

Engineering Contradiction:
Improveyaw rotation torqueVSAvoidfine control
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The system applies different control strategies to different torque sources based on their local characteristics: the first yaw rotation generation control unit manages the high-torque engine output for coarse positioning, while the second yaw rotation generation control unit manages the lower-torque attitude control propellers for fine adjustments. This localized quality approach optimizes control precision for each torque source's operational range.

Inventive Principle:
Principle #3Local quality

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 enables precise control of yaw rotation, improving the aircraft's ability to maintain position and perform tasks requiring fine adjustments without the need for a highly accurate and rigid link mechanism, thus enhancing operational stability and accuracy.

Implementation Method 1

first yaw rotation generated by torques of the plurality of propellers with the pitch adjuster

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 2

second yaw rotation generated by torques generated by a difference in rotation speed between the plurality of attitude control propellers

Methodology Applied
Scientific EffectTorque: Torque

Data Source

PatentEP3375707B1Aircraft and flight system
Publication Date: 2021.05.05 RICOH CO LTD
  • EP3375707B1 patent drawingFigure 1~2
  • EP3375707B1 patent drawingFigure 3
  • EP3375707B1 patent drawingFigure 4

AI summary

An aircraft includes propellers (21, 22) at a center of the airframe (1); a first power source (23); a pitch adjuster (51-1, 51-2, 52); attitude control propellers (31-1, 31-2, 31-3, 31-4); a second power source (32-1, 32-2, 32-3, 32-4); and a control circuit (100) to control attitude of the airframe (1). The control circuit (100) includes a first yaw rotation generation control unit to control first yaw rotation generated by torques of the propellers (21, 22) with the pitch adjuster; and a second yaw rotation generation control unit to control a second yaw rotation generated by torques generated by a difference in rotation speed between the attitude control propellers (31-1, 31-2, 31-3, 31-4). The control circuit is configured to control the first yaw rotation generation control unit and the second yaw rotation generation control unit in accordance with a magnitude of a command value of yaw rotation.