Motor Control Pattern Switching for Middle Start Position Noise Reduction

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Solution Overview

Problem

Existing electromechanical devices face issues with speed tracking errors and high electric currents when restarting the operation knob from a middle position, leading to increased torque and collision noise, which are not effectively managed by existing motor control patterns.

Innovation Solution

The implementation of a motor controller that uses a relative pattern for middle start positions and an absolute pattern for normal start positions, allowing for appropriate target rotational speed control by determining the start position using rotation sensors, thereby reducing speed tracking errors and electric currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the motor is controlled using a fixed absolute pattern for all start positions, then the control system is simple, but speed tracking error increases and large electric current flows when restarting from a middle position

Engineering Contradiction:
Improvecontrol system complexityVSAvoidspeed tracking accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control system dynamically switches between absolute pattern control (for normal starts) and relative pattern control (for restarts from middle positions). The controller determines the start position using rotation sensors and selects the appropriate control pattern accordingly, making the control characteristics adaptive to the operational state rather than fixed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the control parameters by introducing a relative pattern that defines target rotational speed relative to the middle start position. This allows the target speed profile to be adjusted based on the actual start position, optimizing performance for restart scenarios while maintaining simplicity for normal operations

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the motor is controlled using a fixed absolute pattern for all start positions, then the control algorithm is simple, but large torque is applied causing collision noise of components

Engineering Contradiction:
Improvecontrol algorithm complexityVSAvoidcollision noise
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The control algorithm dynamically adapts its behavior based on the detected start position. For restarts from middle positions, the relative pattern provides gentler acceleration characteristics that prevent sudden torque spikes, thereby reducing collision noise in gears and other mechanical components while maintaining algorithmic simplicity through conditional logic

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the target speed is used as defined for normal start positions, then the control pattern is consistent, but speed tracking error increases when restarting from a middle position

Engineering Contradiction:
Improvecontrol pattern consistencyVSAvoidspeed tracking accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The invention modifies the target speed parameters by introducing a relative pattern that is specifically optimized for restart scenarios. The relative pattern defines target rotational speed as a function of the middle start position, allowing the speed profile to be appropriately adjusted for restart conditions while maintaining a consistent control approach for normal starts

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3376662B1Electromechanical device, motor control device and rotation control method
Publication Date: 2021.06.09 ALPS ALPINE CO LTD
  • EP3376662B1 patent drawingFigure 1
  • EP3376662B1 patent drawingFigure 2
  • EP3376662B1 patent drawingFigure 3

AI summary

When a rotation start position of a rotation shaft 132 is a middle start position 31a (i.e., when rotation of the rotation shaft 132 is stopped in the middle and the rotation is restarted), target rotational speed (relative target rotational speed) is defined using a relative pattern 31 that uses the middle start position 31a as a reference, without using an absolute pattern 33 that is defined using a normal rotation start position 33a as a reference. Upon detecting that a condition that absolute target rotational speed corresponding to an angular position detected by a rotation sensor 134 is greater than the relative target rotational speed is not satisfied, motor control is switched so that the absolute pattern 33 is used.