Mobile Construction Robot Positioning With Single-Marker Optical Tracking

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Solution Overview

Problem

Existing mobile construction robots for drilling holes in architectural sites require accurate positioning and orientation, which is time-consuming with current methods involving two separate reflector prisms and a total station, and lacks efficiency when using a single prism.

Innovation Solution

A mobile construction robot uses an optical tracker and a single optical marker to determine its position and orientation, allowing faster alignment and tracking without sacrificing accuracy by measuring the marker's positions relative to the robot and tracker.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two separate reflector prisms and a total station are used for positioning, then measurement accuracy is improved, but the time required for positioning and orientation determination increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidtime for position and orientation determination
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines two separate reflector prisms into a single optical marker that can be tracked by an optical tracker. This merging reduces the number of measurement operations needed while maintaining positioning accuracy, thereby reducing the time required for position and orientation determination.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces the mechanical total station measurement system with an optical tracking system. The optical tracker continuously tracks the optical marker's position in three-dimensional space, enabling real-time position and orientation determination without the time-consuming manual measurement process of the total station.

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

2Productivity

If a single reflector prism is used with a total station, then the positioning speed is improved, but measurement accuracy significantly decreases

Engineering Contradiction:
Improvepositioning speedVSAvoidpositioning accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent replaces the total station measurement system with an optical tracking system that uses a single optical marker. This substitution enables both fast positioning speed and high measurement accuracy by continuously tracking the marker's three-dimensional position optically, rather than through manual total station measurements.

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

3Ease of operation

If initial alignment of the optical tracker towards the optical marker is required, then setup complexity increases, but continuous tracking capability is improved

Engineering Contradiction:
Improveinitial alignment requirementVSAvoidcontinuous tracking capability
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent performs preliminary alignment of the optical tracker towards the optical marker during the initial setup phase. This preliminary action establishes the coordinate system transformation relationships, enabling continuous automatic tracking throughout the robot's operation without requiring repeated alignment operations.

Inventive Principle:
Principle #10Preliminary action

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 faster and accurate determination of the robot's position and orientation, improving operational efficiency by reducing the need for initial alignment and allowing continuous tracking during movement.

Implementation Method 1

an optical tracker and a single optical marker mounted to end effector of the robotic arm. The system achieves a resolution limited by the optical tracker

Methodology Applied
Scientific EffectOptical tracking: LIDAR

Data Source

PatentEP3840919B1Mobile construction robot
Publication Date: 2023.02.22 HILTI AG
  • EP3840919B1 patent drawingFigure 1
  • EP3840919B1 patent drawingFigure 2~3

AI summary

A method of operation the mobile construction robot (1) is based on: Placing an optical tracker (22) on the architectural construction site (5). Parking a driving platform (2) of the mobile construction robot (1) in an area of the architectural construction site (5). Moving an end effector (4) of the mobile construction robot (1) in at least a first position and a second position by controlling a robotic arm (3) mounted on the driving platform (2). Measuring the at least first position and second position relative to the driving platform (2) using sensors (17) mounted on the robotic arm (3). Tracking an optical marker (21) mounted to end effector (4) in the at least first position and second position of the end effector (4) with the optical tracker (22). Measuring the at least first position and second position of the optical marker (21) relative to the optical tracker (22) with the optical tracker (22). And, determining position and orientation of the driving platform (2) based on the at least first position and second position of the end effector (4) measured relative to the driving platform (2) and the at least first position and second position of the optical marker (21) measured relative to the optical tracker (22).