Construction Robot Self-Calibration Using Optical Manipulator Sensing

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Solution Overview

Problem

Existing construction robots face challenges in achieving high position accuracy due to manufacturing tolerances, requiring costly and location-limited calibration processes, especially when manipulators need to be replaced on-site.

Innovation Solution

The use of optical sensors and a control unit on the construction robot allows for on-site calibration without external duplicates, enabling precise determination of the manipulator's position relative to the mobile platform, and automatic correction of deviations, using a combination of optical and non-optical sensors for accurate positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a calibrated duplicate manipulator is used for calibration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveposition accuracyVSAvoidcalibration equipment

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical calibration system (physical duplicate manipulator) with an optical measurement system. Optical sensors capture images of the manipulator at known positions, and image processing algorithms automatically determine position and orientation data, eliminating the need for a calibrated duplicate manipulator while maintaining high measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of using a physical duplicate manipulator, the system creates a digital model (virtual duplicate) of the manipulator based on image data. This virtual duplicate is used for comparison and calibration purposes, significantly reducing the complexity and cost of calibration equipment

Inventive Principle:

Principle #26Copying

2Measurement precision

If calibration is performed at a manufacturing facility, then measurement precision is improved, but loss of time and productivity decrease

Engineering Contradiction:

Improveposition accuracyVSAvoidcalibration time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The construction robot performs calibration autonomously at the construction site without requiring transport to a manufacturing facility. The optical sensors and image processing system enable the robot to self-calibrate by capturing images of itself at known positions and automatically computing correction data, eliminating time loss from transportation and facility scheduling

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system performs calibration measurements at multiple predetermined positions before actual construction work begins. By pre-determining position deviations at these known locations, the system establishes correction data in advance that can be applied during subsequent construction operations, ensuring accuracy without delaying the project timeline

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If a calibrated duplicate is required, then manufacturing precision is maintained, but ease of operation and adaptability worsen

Engineering Contradiction:

Improvemanipulator accuracyVSAvoidcalibration process

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces the complex mechanical calibration process requiring a duplicate manipulator with a simplified optical measurement approach. Image capture and automated processing make the calibration process easier to operate, while the use of multiple predetermined positions ensures manufacturing precision is maintained

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical sensor system serves multiple functions: it captures images for calibration, determines position and orientation data, and verifies manipulator accuracy. This multi-functional approach eliminates the need for specialized calibration equipment, improving ease of operation while maintaining precision across different manipulator configurations

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables cost-effective and site-specific calibration of construction robots, allowing for precise control of manipulators and tools, reducing the need for external calibration devices and enabling direct on-site maintenance and operation.

Implementation Method 1

optical sensors arranged and/or formed at least partially on the mobile platform and a control unit which is configured to determine, using the optical sensors, a position and/or a location of the manipulator

Methodology Applied

Scientific EffectOptical detection: Light

Data Source

PatentEP4279225B1Method for calibrating a construction robot

Publication Date: 2025.01.29 HILTI AG

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AI summary

The invention relates to a construction robot (10) for performing construction work on a building site. It comprises a mobile platform (12), a manipulator (18) movable relative to the mobile platform (12), and optical sensors (62) arranged and/or formed at least partially on the mobile platform (12), and a control unit (38) configured to determine the position and/or orientation of the manipulator (18), in particular of a tool arranged on the manipulator (18), relative to the mobile platform (12) using the optical sensors (62). The invention further relates to a method (1000) for calibrating a construction robot (10). The invention provides a cost-effective, particularly precise construction robot (10).