Fan Swing Head Angle Control Using Brushless Motor Feedback

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Solution Overview

Problem

Current fans with swingable heads use stepping motors that have a short service life, making it difficult to meet user requirements for long-term operation and precise control of the rotation angle.

Innovation Solution

The use of a brushless motor driven by a control device that calculates and adjusts the rotation angle based on feedback from an angle feedback device, such as a potentiometer or infrared photoelectric rotary encoder, to accurately control the swinging head's rotation angle, extending the fan's service life and improving user experience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a stepping motor is used to control the rotation angle of the swinging head, then the rotation angle can be controlled freely, but the service life is short (only thousands of hours)

Engineering Contradiction:
Improverotation angle controlVSAvoidservice life
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the mechanical stepping motor system with a brushless motor system combined with angle feedback devices (potentiometer or infrared photoelectric rotary encoder). This substitution eliminates the mechanical wear issues of stepping motors while maintaining precise rotation angle control through electronic control and feedback mechanisms.

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

2Ease of operation

If a stepping motor is used to control the rotation angle, then direct control is achieved, but it is difficult to meet user requirements for long-term operation

Engineering Contradiction:
Improvedirect controlVSAvoidlong-term operation capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical stepping motor with a brushless motor system that has no mechanical contact wear, significantly improving reliability for long-term operation. The control function is maintained through electronic control circuits and angle feedback devices that provide precise positioning without mechanical degradation.

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

Solution Approach 2:

The patent introduces angle feedback devices (potentiometer or infrared photoelectric rotary encoder) that continuously monitor the rotation angle and provide feedback to the control circuit. This closed-loop feedback system ensures accurate positioning and maintains reliable operation over extended periods by enabling real-time correction and control.

Inventive Principle:
Principle #23Feedback

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 prolongs the service life of the fan and ensures precise control of the rotation angle, enhancing user satisfaction by leveraging the long service life of brushless motors and the accuracy provided by angle feedback devices.

Implementation Method 1

an infrared photoelectric rotary encoder

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP3404826B1Method and device for controlling rotation angle of swinging head of fan, and fan
Publication Date: 2024.01.17 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP3404826B1 patent drawingFigure 1~2
  • EP3404826B1 patent drawingFigure 3~4
  • EP3404826B1 patent drawingFigure 5~6

AI summary

A method and a device are provided for controlling a rotation angle of a swinging head of a fan. The method may be applied in a fan adopting a brushless motor. An angle feedback device is arranged on the swinging head, and the swinging head is driven by the brushless motor to rotate. The device may acquire a parameter outputted by the angle feedback device, where the parameter varies with rotation of the swinging head. The device may calculate a current rotation angle of the swinging head according to the parameter outputted by the angle feedback device and a preset correspondence relationship between parameters and angles. The device may control the swinging head to rotate according to the current rotation angle of the swinging head and a preset target rotation angle.