Single-Axis Servo Drives with Inter-Drive State Sharing

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Solution Overview

Problem

Existing motion control systems with multiple single axis servo drives face increased processing demands on the master controller due to the need for monitoring, calculating, and transmitting state information across all motors within a servo update cycle.

Innovation Solution

A motion control system with a dedicated inter-drive network allows single axis servo drives to share state information and generate control signals based on the state of all motors, reducing the processing burden on the master controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple individual single axis servo drives are used to control individual motors, then each servo drive can control its motor independently, but the master controller processing burden increases due to monitoring, calculating, and transmitting state information for all motors

Engineering Contradiction:
ImproveIndependent servo drive controlVSAvoidMaster controller processing burden
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The system segments the control functionality by distributing state information processing across multiple independent servo drives. Each servo drive maintains its own control algorithm and processes state information locally, rather than centralizing all processing in the master controller. This segmentation reduces the master controller's processing burden while preserving independent control capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A dedicated inter-drive network is introduced as an intermediary communication channel between servo drives. This network enables direct exchange of state information between drives without requiring the master controller to mediate every data transmission, thereby reducing the master controller's communication overhead and processing burden.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the master controller monitors and calculates state information for all motors, then coordinated control can be achieved, but the processing time and complexity increase within the servo update cycle

Engineering Contradiction:
ImproveCoordinated control accuracyVSAvoidProcessing time within servo update cycle
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Servo drives perform preliminary actions by pre-processing and preparing state information locally before it needs to be used for control decisions. Each drive maintains up-to-date state information about its own motor and receives state information from other drives through the inter-drive network, so that when control calculations are needed, the data is already prepared and available, reducing processing time within the update cycle.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Each servo drive serves itself by maintaining its own control algorithm and processing state information locally. Rather than relying on the master controller to perform all calculations, each drive independently uses the state information (both its own and received from other drives) to generate control signals, distributing the computational workload and reducing overall processing time.

Inventive Principle:
Principle #25Self-service

3Device complexity

If a single multi-axis servo drive is used to control all motors, then processing burden is centralized, but the device complexity and cost increase

Engineering Contradiction:
ImproveNumber of servo drive unitsVSAvoidCentralized processing burden
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The system uses multiple independent single-axis servo drive units instead of a single multi-axis drive. Each unit is simpler in design and can be independently replaced or upgraded. The segmentation into multiple simple units achieves the same coordinated control functionality as a complex multi-axis drive while reducing individual device complexity and providing flexibility in system configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each single-axis servo drive unit is designed to be universal and multi-functional, capable of controlling its own motor independently while also participating in coordinated control through the inter-drive network. This universality allows simple single-axis drives to perform the functions previously requiring complex multi-axis drives, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3584650B1Multiple single axis servo drives with a dedicated inter-drive network
Publication Date: 2025.04.02 ANALOGIC CORP
  • EP3584650B1 patent drawingFigure 1
  • EP3584650B1 patent drawingFigure 2~5
  • EP3584650B1 patent drawingFigure 6~7

AI summary

A servo control module for a motion control system with a plurality of individual servo control modules. The servo control module includes a single axis servo drive. The servo control module further includes a set of input pins configured to receive motor state information of motors controlled by single axis servo drives of all of the other of the plurality of servo control modules over a dedicated inter-drive network each servo update cycle. The servo control module further includes a set of output pins configured to transmit the motor state information of a motor controlled by the single axis servo drive and the received state information over the inter-drive network of motors each servo update cycle.