Pressure Roller Servo Control for Uniform Robotic Hemming Force

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Solution Overview

Problem

Conventional robot systems for pressure processing, such as hemming, face challenges with inconsistent pressing force due to robot arm deflection, leading to reduced quality and a complex trial-and-error teaching procedure, affecting readiness and processing quality.

Innovation Solution

A robot system equipped with a servomotor-driven linear motion mechanism for the pressure roller, allowing precise control of pressing force and posture, ensuring uniform pressure application and improved processing quality through advanced control algorithms and mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a fluid cylinder is used to generate pressing force, then the pressing mechanism can be implemented, but the robot arm deflects largely under pressure, resulting in insufficient pressing force

Engineering Contradiction:
Improvepressing forceVSAvoidpressing force consistency
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The control unit receives position information from the detection unit about the pressure roller's position and adjusts the servomotor's output force accordingly. This feedback mechanism ensures that the pressing force remains consistent even when the robot arm deflects, maintaining manufacturing precision while achieving sufficient pressing force.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the conventional fluid cylinder-based pressing mechanism with a servomotor-driven linear motion mechanism. This substitution enables precise control of the pressure roller's position and pressing force through electronic control, eliminating the arm deflection issue associated with fluid pressure systems while maintaining the ability to generate sufficient pressing force.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a fluid cylinder is used for pressure application, then the mechanism can be implemented, but numerous trials and errors are required for teaching, resulting in a complicated procedure

Engineering Contradiction:
Improvesetup simplicityVSAvoidteaching time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The detection unit continuously monitors the pressure roller's position and feeds this information back to the control unit. This real-time feedback eliminates the need for trial-and-error teaching by automatically adjusting the pressing force based on actual position, significantly reducing setup time and simplifying the manufacturing process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-adjustment through the feedback loop between the detection unit and servomotor control. The system automatically compensates for position variations and maintains optimal pressing force without requiring extensive manual teaching or adjustment, thereby reducing setup complexity and time loss.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2868403B1Robot system and method for producing to-be-processed material
Publication Date: 2021.02.17 YASKAWA DENKI KK
  • EP2868403B1 patent drawingFigure 1
  • EP2868403B1 patent drawingFigure 2
  • EP2868403B1 patent drawingFigure 3A~3B

AI summary

A robot system includes an end effector, a robot arm, and a controller. The end effector includes a pressure roller and a linear motion mechanism. The linear motion mechanism is configured to move the pressure roller with respect to a pressed surface. The robot arm is configured to support the end effector. The controller is configured to control the linear motion mechanism to move the pressure roller to make a pressing force of the pressure roller against the pressed surface approximately uniform.