Robot Controller Adjusting Spray Flow for Consistent Coating Thickness

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Solution Overview

Problem

Existing paint robot controllers programmed with setpoint spray gun speed and fluid flow per unit time lack adaptability to fluctuations in actual robot arm speed, leading to potential thickness deviations and inefficiencies.

Innovation Solution

A robot controller that adjusts setpoint fluid flow and other spray gun parameters using compensation functions based on actual speed deviations, ensuring consistent coating thickness and efficient fluid use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the robot controller uses fixed setpoint spray gun speed and fluid flow per unit time, then the programming and control is simple, but the coating thickness becomes inconsistent due to speed fluctuations

Engineering Contradiction:
Improvecoating thickness consistencyVSAvoidcontroller complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The controller continuously monitors the actual robot arm speed and uses this feedback to dynamically adjust the fluid flow rate. The control system compares the actual speed with the reference speed and modifies the fluid flow accordingly to maintain constant coating thickness, resolving the contradiction between simplicity and precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the fluid flow parameter dynamically based on actual speed variations. When speed deviates from the reference, the controller adjusts the fluid flow rate to compensate, maintaining consistent coating thickness without requiring complex hardware modifications.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the robot controller dynamically adjusts fluid flow based on actual speed, then coating thickness consistency is maintained, but the control system complexity increases

Engineering Contradiction:
Improvecoating thickness consistencyVSAvoidcontroller complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The controller implements a feedback mechanism where actual speed measurements are continuously used to adjust fluid flow. This closed-loop control maintains precision while keeping the controller architecture relatively simple by using direct speed-to-flow correspondence.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the robot arm's own speed information (already available for motion control) to automatically regulate fluid flow without requiring external sensors or complex measurement systems. The controller serves itself by utilizing existing operational data.

Inventive Principle:
Principle #25Self-service

3Productivity

If the robot moves faster than the setpoint speed, then productivity increases, but coating thickness becomes insufficient

Engineering Contradiction:
Improvepainting speedVSAvoidcoating thickness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

When the robot arm moves faster than the reference speed, the controller increases the fluid flow rate to compensate. This parameter adjustment ensures that even at higher speeds, the coating thickness remains consistent, allowing productivity gains without sacrificing quality.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If the robot moves slower than the setpoint speed, then coating thickness increases, but fluid waste occurs

Engineering Contradiction:
Improvecoating thicknessVSAvoidfluid waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The feedback mechanism detects when the robot arm moves slower than reference speed and automatically reduces the fluid flow rate. This prevents excessive coating buildup and fluid waste, maintaining optimal coating thickness while improving material efficiency.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4214024B1A controller for a paint robot
Publication Date: 2026.04.15 ABB (SCHWEIZ) AG
  • EP4214024B1 patent drawingFigure 1~2
  • EP4214024B1 patent drawingFigure 3~5
  • EP4214024B1 patent drawingFigure 6

AI summary

A robot controller (112, 114, 631, 632) is adapted to execute a program (610) comprising an indication of a setpoint speed of a robot arm (120), an indication of a contemporaneous setpoint fluid flow per unit time of a spray gun (122) supported by the robot arm, and an indication of a contemporaneous further setpoint quantity of the spray gun. The robot controller is configured to obtain an estimate of actual speed of the robot arm; determine whether the estimate deviates from the setpoint speed; and, in case of a deviation, adjust the setpoint fluid flow per unit time in accordance with a first compensation function. In an embodiment, the robot controller is further configured to concurrently adjust, in case of a deviation, the further setpoint quantity in accordance with a second compensation function, which is different from the first compensation function.