Servo Motor Serial Bus Control Circuit

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Solution Overview

Problem

Existing servo motor control systems face challenges in efficiently driving multiple motors due to the complexity and size constraints of large-capacity inverter units, leading to increased costs and processing delays, particularly when using relay units for serial bus communication.

Innovation Solution

A servo motor control system with a serial bus control circuit that allows for the generation and transmission of current or torque commands to multiple servo amplifiers in different control modes, eliminating the need for relay units and simplifying the system by processing command information before it reaches the serial bus, thereby reducing processing delays and enabling downsizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If relay units are used for serial bus communication to control multiple servo amplifiers, then system compatibility and control capability are improved, but processing delays increase and response speed deteriorates

Engineering Contradiction:
Improvecontrol capabilityVSAvoidprocessing delay
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent extracts and removes the relay unit from the control system. The controller directly communicates with multiple servo amplifiers through the serial bus without intermediate relay units, eliminating the processing delay caused by data reception, conversion, and retransmission at the relay unit while maintaining the ability to control multiple servo amplifiers in different modes.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If relay units are used for serial bus communication, then control flexibility is improved, but system complexity increases

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

Solution Approach 1:

The relay unit is extracted and removed from the system. The controller directly manages multiple servo amplifiers through the serial bus, eliminating the need for additional relay unit hardware and reducing system complexity while maintaining control flexibility through software-based mode switching.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The controller is designed to perform multiple functions directly, including controlling servo amplifiers in master-slave mode, synchronous speed control mode, and independent control mode. This multi-functionality eliminates the need for separate relay units while maintaining control flexibility.

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

3Adaptability or versatility

If multiple small-capacity inverter units are connected in parallel to drive large-capacity motors, then system adaptability is improved, but the number of motor driving command generation units increases

Engineering Contradiction:
Improvesystem adaptabilityVSAvoidnumber of command generation units
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The controller is designed with multi-functionality to control multiple servo amplifiers simultaneously in different modes. A single controller can manage servo amplifiers in master-slave mode for coordinated control, in synchronous speed control mode for speed synchronization, or in independent control mode for separate operations, eliminating the need for separate command generation units for each motor.

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

Solution Approach 2:

The control system dynamically switches between different control modes (master-slave, synchronous speed control, independent control) based on operational requirements. This dynamic adaptability allows a single controller to efficiently manage multiple motors without requiring dedicated command generation units for each motor configuration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2085847B1Servo motor control system
Publication Date: 2011.12.21 FANUC LTD
  • EP2085847B1 patent drawingFigure 1
  • EP2085847B1 patent drawingFigure 2A~2B
  • EP2085847B1 patent drawingFigure 3

AI summary

A table containing correspondence between "n" and "m" is set in a control circuit of a servo control system so that the current command data in the m-th (m = 1, 2, 3 ...) current command register is assigned to the n-th (n = 1, 2, 3 ...) servo amplifier. When data is specified in this table to satisfy "n = m", the current command data in the n-th current command register is passed to the n-th servo amplifier. When "m = 1" is set for "n = 1" and "m = 1" is set for "n = 2" in this table, the current command data stored in the first current command register is passed to the first and second servo amplifiers.