Painting Robot Dynamics Matching for Consistent Coating Paths

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Solution Overview

Problem

In modern painting installations, painting robots often experience deviations in speed, acceleration, and path, leading to uneven painting results, reduced reproducibility, and increased complexity in maintaining optimal painting parameters, which complicates achieving consistent and symmetrical paint layers on motor vehicle bodies and add-on parts.

Innovation Solution

The method involves adapting the dynamic behavior and load characteristics of multiple robots to align them, ensuring consistent performance across different position ranges, allowing for symmetrical painting paths and reduced robot-specific variability, thereby achieving consistent painting results independent of robot position or performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the painting robot travels at constant speed following the taught path, then the painting result reproducibility is improved, but the robot may exceed maximum motor torque or permissible torque limits

Engineering Contradiction:
Improvepainting result reproducibilityVSAvoidmotor torque
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The patent applies dynamics by allowing the robot to adapt its speed dynamically during painting operations. The control system monitors torque limits and adjusts the painting speed in real-time, enabling the robot to maintain constant speed only where torque permits and reduce speed where torque limits would be exceeded, thus resolving the contradiction between maintaining painting precision and staying within force limits.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the painting robot reduces speed to avoid exceeding torque limits, then the robot can follow the painting path correctly, but the painting productivity decreases

Engineering Contradiction:
Improvepath following accuracyVSAvoidpainting speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies local quality by implementing different speed profiles for different sections of the painting path. Instead of uniformly reducing speed across the entire path, the control system identifies specific zones where torque limits would be exceeded and only reduces speed in those local areas, maintaining optimal painting speed in zones where torque requirements are within limits, thus preserving overall productivity while ensuring path accuracy where needed.

Inventive Principle:
Principle #3Local quality

3Duration of action of stationary object

If the painting robot executes painting programs within maximum acceleration and speed limits using dynamic robot model, then the robot service life is extended, but the painting path deviation and speed reduction occur

Engineering Contradiction:
Improverobot service lifeVSAvoidpainting path accuracy
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies feedback by implementing a control system that continuously monitors the robot's actual position, speed, and acceleration during painting operations. The system compares the actual trajectory against the taught path and dynamically adjusts control parameters to compensate for deviations caused by operating at maximum acceleration and speed limits, thus maintaining painting path accuracy even when operating at extended performance levels that prolong robot service life.

Inventive Principle:
Principle #23Feedback

4Productivity

If multiple robots are used for painting different sides of workpieces, then the painting productivity is increased, but the dynamic behavior and load characteristics differ between robots causing inconsistent painting results

Engineering Contradiction:
Improvepainting throughputVSAvoidpainting result consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting painting parameters such as speed, acceleration, and atomizer positioning for each robot based on its specific dynamic characteristics and load conditions. The control system characterizes each robot's performance parameters and modifies the painting program parameters accordingly, enabling multiple robots with different dynamic behaviors to produce consistent painting results by compensating for individual variations through parameter adaptation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2673679B1Adapting the dynamics of at least one robot
Publication Date: 2021.03.31 DUERR SYST AG
  • EP2673679B1 patent drawingFigure 1
  • EP2673679B1 patent drawingFigure 2a~3c
  • EP2673679B1 patent drawingFigure 4

AI summary

The invention relates to a method for controlling a robot or a first robot (LR1) and at least one further second robot (LR2), wherein the robot or the first robot (LR1) and the at least one further second robot (LR2) are provided for traversing a plurality of positioning ranges (SB11, SB22) during operation. A dynamic behavior and/or a loading characteristic of the robot in at least one first positioning range is particularly adapted to a dynamic behavior and/or a loading characteristic in at least one second positioning range of the robot, and/or a dynamic behavior and/or a loading characteristic of the first robot (LR1) in at least one first positioning range (SB11)is adapted to a dynamic behavior and/or a loading characteristic of the second robot (LR2) in at least one second positioning range (SB22). The invention further relates to a corresponding control system, to a corresponding computer program or computer-readable medium, and to a corresponding robot.