Motor Rotation Angle Detection During Inertial Window Motion

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Solution Overview

Problem

Existing window position detecting devices struggle to accurately detect the rotation angle of a motor due to inertial rotation, especially when changes in temperature affect the ease of opening and closing the window, leading to inaccuracies in detecting the fully closed or fully opened positions.

Innovation Solution

A rotation angle detecting method that measures the current flowing through a motor and calculates the rotation angle based on the measured current, considering the rotational angular velocity immediately before stopping the motor, and the time periods before and after a polarity inversion and zero current points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the rotation angle is calculated based on the number of ripples of driving current, then the window position can be detected, but the detection accuracy deteriorates when the motor undergoes inertial rotation due to temperature changes

Engineering Contradiction:

Improverotation angle detection accuracyVSAvoiddetection reliability under temperature variation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent changes the detection parameter from ripple count to current integral value. By integrating the current over the inertial rotation period (from polarity inversion to zero current), the system obtains a parameter that directly reflects the inertial rotation angle, making the detection accurate under varying temperature conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/ripple-based detection method with an electrical measurement method. Instead of counting mechanical ripples in the driving current, the system measures and integrates the electrical current during inertial rotation, substituting a more reliable electrical parameter for the mechanical indicator.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If the motor is stopped quickly to improve response time, then the detection speed increases, but the inertial rotation angle becomes harder to measure accurately

Engineering Contradiction:

Improvedetection speedVSAvoidinertial rotation angle measurement accuracy

Core Design Contradiction:

SpeedVSMeasurement precision

Solution Approach 1:

The patent uses feedback from the current measurement to determine the inertial rotation period. By monitoring when the current polarity inverts and when it reaches zero, the system automatically identifies the exact duration of inertial rotation, enabling accurate measurement regardless of how quickly the motor is stopped.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary measurement of the current characteristics during motor operation. By continuously monitoring the current waveform and identifying the polarity inversion point and zero current point, the system prepares the data needed for accurate inertial rotation angle calculation before the measurement is required.

Inventive Principle:

Principle #10Preliminary 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 method enables accurate detection of the rotation angle during inertial rotation, even under varying temperature conditions, thereby improving the accuracy of window position detection and extending the method's applicability to other motor-driven systems.

Implementation Method 1

measuring a current flowing through a motor, and obtaining a rotation angle of the motor based on a value of the measured current

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

obtaining the rotation angle in an inertial rotation of the motor based on a rotational angular velocity of the motor immediately before a first time point

Methodology Applied

Scientific EffectInertia: Inertia

Data Source

PatentUS12206352B2Rotation angle detecting method, recording medium storing rotation angle detecting program, and rotation angle detecting device

Publication Date: 2025.01.21 ALPS ALPINE CO LTD

AI summary

A rotation angle detecting method includes measuring a current flowing through a motor, and obtaining a rotation angle of the motor based on a value of the measured current. The obtaining of the rotation angle of the motor includes obtaining the rotation angle in an inertial rotation of the motor based on a rotational angular velocity of the motor immediately before a first time point, a time period from the first time point to a second time point, and a time period from the second time point to a third time point. The first time point is a time point at which driving of the motor is stopped, the second time point is a time point at which a polarity of the value of the measured current is inverted, and the third time point is a time point at which the value of the measured current becomes zero.