Multi-Axis Drive Torque Control via Homogeneous Data Bus

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Solution Overview

Problem

Existing multi-axis drive systems face challenges in simple and efficient communication and control between mechanically coupled drives, often resulting in uneven data transmission rates and requiring cross-communication between drives, which complicates regulation and control.

Innovation Solution

A method where a higher-level computer connects to drives via a data bus, determining setpoint values for each drive based on actual values, with each drive having a dedicated controller to regulate speed and torque, ensuring uniform data transmission and eliminating master-slave regulation, allowing for flexible control using either torque or position variables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If master-slave control is used to operate mechanically coupled drives, then one drive can be controlled differently from others, but data transmission rates become uneven and communication complexity increases

Engineering Contradiction:
Improvecontrol flexibilityVSAvoidcommunication complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies equipotentiality by treating all drives in the multi-axis system equally, with each drive having the same controller structure and participating in torque distribution calculations. No drive is designated as master or slave; instead, all drives communicate uniformly via the data bus and contribute to determining target torque values based on their actual torque feedback. This eliminates the hierarchical complexity of master-slave control while maintaining control flexibility through distributed torque management.

Inventive Principle:
Principle #12Equipotentiality

2Reliability

If cross-communication between drives is implemented, then coordination between drives is improved, but system complexity and regulation difficulty increase

Engineering Contradiction:
Improvedrive coordinationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses the higher-level computer as an intermediary that centralizes the coordination function. Instead of drives communicating directly with each other (cross-communication), all torque-related information flows through the higher-level computer, which calculates target torque values and distributes speed setpoints to individual drives. This mediator approach maintains reliable coordination while simplifying the system architecture by eliminating direct drive-to-drive communication paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If different data transmission rates are assigned to different drives, then specific drives can receive more control information, but uniformity of operation is lost

Engineering Contradiction:
Improvecontrol information deliveryVSAvoidoperational uniformity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies homogeneity by assigning uniform data transmission rates to all drives connected via the data bus. Each drive receives and transmits the same types of control information (actual torque values, speed setpoints, target torque values) at equivalent rates. This homogeneous communication scheme ensures operational uniformity across all drives while maintaining productivity through efficient use of the data bus for torque distribution control.

Inventive Principle:
Principle #33Homogeneity

Data Source

PatentEP3501093B1Method for operating a system with drives which are mechanically coupled together and with a higher-level computer, and system
Publication Date: 2020.12.23 SEW EURODRIVE GMBH & CO KG
  • EP3501093B1 patent drawingFigure 1
  • EP3501093B1 patent drawingFigure 2
  • EP3501093B1 patent drawing

AI summary

The invention relates to a method for operating a system with drives which are mechanically coupled together and with a higher-level computer which is connected to the drives via a data bus connection and to a system. A respective torque actual value is determined in each drive and transmitted to the higher-level computer, in particular by means of the data bus connection. For each drive, the higher-level computer determines a torque target value assigned to the respective drive, and the higher-level computer has regulators. Each drive is paired with one of the regulators, in particular in a unique manner, and the regulator assigned to each drive regulates the torque actual value of the respective drive to the torque target value of the respective drive in that the regulator determines a speed target value assigned to the respective drive as a control value and transmits same to the respective drive, in particular by means of the data bus connection. Each drive has a respective regulator to which the drive electric motor speed actual value determined in the drive is supplied and which regulates said respective speed actual value to the respective speed target value transmitted from the higher-level computer in that the regulator adjusts the motor voltage or the motor current of the electric motor of the respective drive.