Robot Assembly Position Control Using Absolute Measurement Feedback

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Solution Overview

Problem

Existing robot control methods struggle to achieve high process accuracy in assembling components, particularly in complex production environments, as they rely on robot accuracy rather than process accuracy, leading to inefficiencies and manual intervention.

Innovation Solution

A method for controlling robots using absolute measurement data to adjust component positioning, allowing for adaptive control based on process feedback rather than robot feedback, thereby achieving high process accuracy without the need for continuous manual monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If robot control methods rely on robot accuracy, then robot positioning is simplified, but process accuracy in assembling components deteriorates

Engineering Contradiction:
Improverobot control simplicityVSAvoidcomponent positioning accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where actual installation positions of components are measured and compared with target positions. Deviation values are calculated and used to adjust the robot's nominal position for subsequent installations. This closed-loop feedback system transforms the open-loop robot control into a process-controlled system that continuously corrects positioning errors, thereby achieving high manufacturing precision without complicating the fundamental robot control architecture.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces reliance on mechanical robot accuracy with a measurement and calculation-based system. Instead of depending on the robot's mechanical precision, the system uses measurement devices to detect actual positions, calculates deviations, and applies computational corrections to the nominal positions. This substitution of mechanical precision requirements with measurement and calculation processes enables high component positioning accuracy while maintaining simple robot control.

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

2Manufacturing precision

If continuous manual monitoring is implemented to ensure process accuracy, then manufacturing precision improves, but productivity deteriorates due to increased monitoring time

Engineering Contradiction:
Improvecomponent positioning accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements a self-service system where the measurement and correction processes are automatically performed by the system itself without requiring continuous manual monitoring. The electronic control unit automatically measures actual installation positions, calculates deviation values, and adjusts nominal positions for subsequent components. This automation eliminates the need for manual intervention while maintaining high manufacturing precision, thereby preserving productivity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The automated feedback system continuously monitors and corrects positioning errors without manual intervention. By establishing a self-regulating control loop that automatically measures, calculates deviations, and applies corrections, the system achieves high manufacturing precision while eliminating the time-consuming manual monitoring that would otherwise reduce productivity.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If adaptive control based on process feedback is implemented, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:
Improveprocess accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a universal control approach where the electronic control unit performs multiple functions: it controls the robot's movement, processes measurement data, calculates deviation values, and adjusts nominal positions. By consolidating these diverse functions into a single control system, the patent achieves high manufacturing precision through adaptive control while minimizing the increase in device complexity. The same control unit that manages basic robot operations also handles the sophisticated feedback and correction processes.

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

4Manufacturing precision

If absolute measurement data is used to adjust nominal position, then process accuracy improves, but loss of time occurs in calculating and adjusting positions

Engineering Contradiction:
Improvecomponent positioning accuracyVSAvoidposition adjustment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing nominal positions for component installations. Before actual installations occur, the system prepares the nominal position data that will be used as reference. When measurement data becomes available, the system quickly adjusts these pre-prepared nominal positions by adding deviation values, rather than performing complex calculations from scratch. This preliminary preparation significantly reduces the time required for position adjustments while maintaining high manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4104978B1Method for controlling a robot, data processing apparatus, computer program product, and computer-readable storage medium
Publication Date: 2026.02.18 BAYERISCHE MOTOREN WERKE AG
  • EP4104978B1 patent drawingFigure 1
  • EP4104978B1 patent drawingFigure 2
  • EP4104978B1 patent drawingFigure 3

AI summary

The invention relates to a method for controlling a robot by an electronic control unit (2), the robot installing at least one first component on a second component thereby producing a first assembly comprising the first and second components, wherein the method comprises determining, by the electronic control unit (2), a target position at which the first component is to be installed on the second component by the robot. The method comprises determining, by the electronic control unit (2), absolute measurement data characterizing at least one actual installation position at which a first component of at least one completed second assembly is installed on a second component of the completed second assembly identical in construction to the first assembly to be produced by the robot.