Marker-Based Pose Calibration for Accurate 3D Measurement Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automation systems, such as robots, have limited accuracy in positioning their end effectors, which restricts their use in metrology-level measurements and requires time-consuming and costly methods like retroreflector tracking.
Innovation Solution
A system that combines a pose manipulation system with a position measurement system and a pose tracking system, using photogrammetric markers to record and track the relative poses of the measurement device, allowing for accurate measurement paths to be recorded and repeated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing automation systems use standard positioning methods, then the system is simple and easy to operate, but the positioning accuracy is low and cannot achieve metrology level measurements
Solution Approach 1:
The patent introduces photogrammetric markers as an intermediary element between the automation system and the position measurement system. These markers serve as mediators that enable precise position tracking without requiring complex retroreflector tracking systems. The markers are detected by the position measurement system to determine the pose of the end effector, achieving high measurement precision while keeping the overall system relatively simple.
Solution Approach 2:
The patent creates a digital copy or model of the measurement path by recording the sequence of poses. This recorded path can then be replayed repeatedly with high repeatability. The system captures the exact positions and orientations during calibration and stores them as a reference path, allowing subsequent operations to follow this recorded trajectory, thereby achieving metrology-level accuracy without complex real-time control.
2Measurement precision
If retroreflector tracking is used to achieve high measurement accuracy, then measurement precision improves, but the system becomes more expensive and time-consuming
Solution Approach 1:
The patent records the measurement path as a sequence of poses during an initial calibration phase and stores this digital copy for repeated use. Once the path is recorded, it can be replayed multiple times without requiring repeated complex calibration procedures. This significantly reduces the time loss for subsequent measurements while maintaining high measurement accuracy through the recorded reference path.
Solution Approach 2:
The system performs preliminary calibration by recording the measurement path in advance. During this preliminary action, the system captures the exact positions and orientations needed for accurate measurement. This pre-recorded information is then used for subsequent measurements, eliminating the need for repeated time-consuming calibration procedures and reducing overall measurement time.
3Extent of automation
If the automation system determines its own path to end positions, then the system operates autonomously, but the intermediate positions cannot be accurately known
Solution Approach 1:
The patent implements a feedback mechanism where the position measurement system continuously monitors the actual position of the end effector during path execution. The system compares the actual position with the recorded reference path and uses this feedback information to determine accurate intermediate positions. This feedback loop enables the autonomous system to know its precise location at intermediate points while maintaining autonomous operation.
Solution Approach 2:
The photogrammetric markers serve as intermediaries that provide measurable reference points for determining intermediate positions. The position measurement system detects these markers to calculate the exact pose of the end effector at any point during movement, enabling accurate knowledge of intermediate positions while the system operates autonomously without continuous human intervention.
4Measurement precision
If photogrammetric markers are used for position tracking, then measurement accuracy improves, but the device complexity increases due to additional tracking components
Solution Approach 1:
The patent uses photogrammetric markers that can be detected and tracked using standard vision systems rather than complex specialized tracking hardware. The markers create a visual copy or representation of position information that can be processed by image processing algorithms, achieving high measurement accuracy while avoiding the need for complex retroreflector tracking systems or specialized sensors.
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 approach enables high-reliability, accurate 3D coordinate measurements by interpolating precise positions based on recorded paths, improving measurement accuracy without the need for expensive and time-consuming retroreflector tracking.
Implementation Method 1
using the detection of photogrammetric markers
Data Source
AI summary
A method for calibration of a system for tracking a measurement system is provided. The method includes recording a path of relative poses that the system is in when acquiring three-dimensional (3D) coordinates of an object by a measurement system. The recording the path includes moving the system sequentially through relative poses between a measurement system and an object, at which the measurement system measures the 3D coordinates and the pose tracking system records a relative pose. The pose manipulation system is caused to move sequentially along the poses in the path, and the measurement system measures the 3D coordinates and applying the recorded poses. The relative pose is calibrated between the tracked manipulated coordinate system and one of a coordinate system of the object and the measurement system. The measured positions are transformed based on the calibrated relative pose and the tracked relative pose into the common coordinate system.