Mechanical Component Design for Servo Vibration Stability Mapping

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Solution Overview

Problem

Existing design methods for mechanical devices driven by feedback-controlled electric motors lack comprehensive guidance on how mechanical component properties affect abnormal vibrations, leading to inadequate prevention and suppression of such vibrations.

Innovation Solution

A design assist apparatus and method that computes the poles of a transfer function associated with vibration modes of mechanical devices, creating a stability determination diagram to visually represent the influence of mechanical component characteristics on abnormal vibrations, allowing users to select or modify components to prevent or suppress vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the gain constant of the feedback control system is increased to improve responsiveness and precision, then the responsiveness and precision of the servomotor increases, but abnormal vibration occurs at the natural frequency of the mechanical system

Engineering Contradiction:
Improveprecision of rotational movementVSAvoidabnormal vibration
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The invention performs preliminary analysis of the mechanical system's natural frequencies and stability characteristics before finalizing the control system design. By computing the pole of the transfer function and creating a stability determination diagram in advance, the design can adjust mechanical parameters to avoid resonance conditions before they cause harmful vibrations, thus preventing the contradiction from occurring in the first place

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes mechanical parameters such as moment of inertia and stiffness of mechanical components to shift the natural frequency of the mechanical system away from the control system's operating frequency range. By adjusting these parameters, the system can maintain high gain constants for precision while avoiding abnormal vibrations through frequency separation

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional design methods are used that focus only on control system characteristics, then control system performance can be optimized, but the user lacks understanding of how mechanical component properties affect abnormal vibrations

Engineering Contradiction:
Improvecontrol system performanceVSAvoidinformation on mechanical component influence
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The invention segments the analysis into distinct components: mechanical parameter analysis, transfer function computation, pole calculation, and stability diagram generation. This segmentation allows the user to understand the specific influence of each mechanical component parameter on system stability while maintaining overall control system performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stability determination diagram serves as an intermediary tool that bridges the gap between mechanical component properties and control system performance. It visually represents the relationship between mechanical parameters and system stability, providing the user with actionable information without compromising control system optimization

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the mechanical system is designed without considering higher-order natural frequencies, then design complexity is reduced, but adequate information on vibrations that may occur in the mechanical device is not provided

Engineering Contradiction:
Improvedesign complexityVSAvoidvibration information completeness
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The invention computes and displays stability information for multiple vibration modes (higher-order natural frequencies) even though the user may only be primarily concerned with the fundamental mode. This excessive action provides comprehensive vibration information without significantly increasing design complexity, as the additional computational burden is manageable and the visual presentation remains clear

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3731035B1Design assist device, design assist method, and design assist program
Publication Date: 2025.03.26 MIKI PULLEY
  • EP3731035B1 patent drawingFigure 1~2
  • EP3731035B1 patent drawingFigure 3
  • EP3731035B1 patent drawingFigure 4~6

AI summary

In the design of a mechanical component for a mechanical device driven by a feedback controlled electric motor, the user is enabled to easily know how the properties of mechanical component affect the generation of abnormal vibrations of the mechanical device. In a design assist apparatus (1), the processor (11) is configured to set a plurality of parameters of a mathematical model of an analysis target component selected from one or more mechanical components (24, 56, 58) forming the mechanical device, compute a pole of a transfer function of the mechanical device associated with one or more vibration modes of the mechanical device according to the parameters, and create a stability determination diagram including an isoline of a real part of the pole of the transfer function.