Robot Grinding Cover Adjustment for Tool Wear Compensation

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Solution Overview

Problem

Robot-assisted grinding devices face challenges due to tool wear, which affects the grinding wheel's diameter, leading to incorrect positioning and reduced suction effectiveness, as the existing systems rely on pre-programmed trajectories that do not account for tool wear, resulting in suboptimal grinding performance.

Innovation Solution

A robot-assisted grinding device with a manipulator, a linear actuator, and an adjustable end stop, where the position of the end stop is set based on the current deflection of the actuator to maintain consistent contact force and gap size between the grinding wheel and the workpiece, ensuring accurate positioning and suction effectiveness despite tool wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a pre-programmed trajectory is used for the TCP, then the manipulator can move the grinding tool along a defined path, but the grinding tool positioning becomes incorrect due to tool wear

Engineering Contradiction:
Improveautomated grinding processVSAvoidgrinding tool positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The end stop position is made dynamically adjustable based on the measured grinding tool diameter. Instead of using a fixed pre-programmed trajectory, the system continuously adapts the TCP reference position by adjusting the end stop location according to the actual tool dimensions, thereby maintaining positioning accuracy despite tool wear.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements a feedback mechanism where the grinding tool diameter is measured and used to adjust the end stop position. This closed-loop control ensures that the TCP reference position is continuously updated to compensate for tool wear, maintaining manufacturing precision throughout the grinding process.

Inventive Principle:
Principle #23Feedback

2Force

If the grinding wheel diameter decreases due to wear, then the peripheral speed decreases, but the grinding machine must be brought closer to the workpiece surface

Engineering Contradiction:
Improveprocess forceVSAvoidadjustment mechanism
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The system performs self-adjustment by automatically measuring the grinding tool diameter and adjusting the end stop position accordingly. This self-service mechanism compensates for tool wear without requiring external intervention or complex manual adjustment procedures, maintaining process force while minimizing device complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If the grinding wheel wears out, then the diameter decreases, but the gap size between the protective cover and workpiece surface changes, reducing suction effectiveness

Engineering Contradiction:
Improvesuction effectivenessVSAvoidgap size adjustment
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The adjustable end stop mechanism serves multiple functions: it maintains the TCP reference position for accurate positioning and simultaneously maintains the optimal gap size between the protective cover and workpiece surface. This multi-functionality ensures both positioning accuracy and suction effectiveness without requiring separate adjustment mechanisms.

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

Data Source

PatentEP3439836B1Robot-aided grinding apparatus
Publication Date: 2023.03.29 FERROBOTICS COMPLIANT ROBOT TECH
  • EP3439836B1 patent drawingFigure 1~2(b)
  • EP3439836B1 patent drawingFigure 3~4
  • EP3439836B1 patent drawingFigure 5a~5b

AI summary

Described is an apparatus for robot-aided grinding, comprising the following: a manipulator, a linear actuator, and a grinding machine which includes a rotating grinding tool and is connected to the manipulator via the linear actuator. The apparatus further comprises a protective cover that partially surrounds the rotating grinding tool, the rotating grinding tool protruding from the protective cover at least on a first side. An adjusting mechanism is provided which connects the protective cover to the grinding machine and is designed to adjust the position of the protective cover in relation to the grinding machine.