Dual-Motor Closed-Loop Synchronization for Shared Axis Control

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Solution Overview

Problem

Existing methods for synchronously controlling multiple motors driving the same axis or moving the same load suffer from reduced accuracy, mechanical blocking, and difficulty in balancing motors of different sizes or types.

Innovation Solution

The method involves using the same control loop data set for closed-loop control of each drive unit, ensuring that all drive units operate based on identical position, speed, and other relevant data, thereby maintaining consistent and accurate control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If one motor is used as a parent and the other as a child in a master-slave configuration, then the control structure is simplified, but the child motor cannot operate in closed loop and performance is reduced

Engineering Contradiction:
Improvecontrol structureVSAvoidmotor performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control system is segmented into independent drive units, each capable of autonomous closed-loop control. Instead of a hierarchical master-slave structure, each motor controller operates independently with its own control loop, allowing both motors to maintain full performance while working together on the same axis.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If motors are wired in parallel, then the control implementation is simplified, but power scaling benefits are not achieved and accuracy is reduced

Engineering Contradiction:
Improvecontrol implementationVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Each drive unit implements closed-loop control with feedback from encoders or other position sensors. The control system continuously monitors motor position and adjusts control signals to maintain accurate positioning, enabling both motors to contribute effectively to power scaling while maintaining high precision.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If different motors or motor sizes are used, then system flexibility is increased, but balancing the motors becomes difficult and mechanical blocking can occur

Engineering Contradiction:
Improvemotor configuration flexibilityVSAvoidmotor balancing
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control system dynamically adjusts the contribution of each motor based on real-time conditions. By independently controlling each motor's torque and position, the system can adapt to different motor sizes and characteristics, automatically balancing their contributions to prevent mechanical blocking while maintaining operational flexibility.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4498594A1Method for synchronously controlling two motors
Publication Date: 2025.01.29 SCHNEIDER ELECTRIC IND SAS
  • EP4498594A1 patent drawingFigure 1A~1C
  • EP4498594A1 patent drawingFigure 2
  • EP4498594A1 patent drawingFigure 3

AI summary

The present invention relates to a method for synchronously controlling a first motor and a second motor, wherein the first motor is controlled by a first drive unit, the second motor is controlled by a second drive unit, wherein the first motor and the second motor work together to drive the same axis and/or to move the same load, wherein the drive units each perform a closed loop control for driving the respective motor, wherein the closed loop control of each of the drive units is based on the same control loop data set.