Robot End Effector Error Observer With External Metrology Feedback
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Solution Overview
Problem
Industrial robots lack the accuracy required for high-precision manufacturing tasks due to kinematic errors, which existing methods to integrate external metrology tracking systems are either too expensive or do not adequately address the non-deterministic behavior of low-bandwidth interfaces.
Innovation Solution
A control system that iteratively corrects the position and orientation of a robot end effector using a metrology tracking system and a computer to compensate for kinematic errors by combining robot and tracker measurements, applying correction commands to the robot controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If industrial robots are used for high-precision manufacturing tasks, then productivity is improved, but manufacturing precision deteriorates due to kinematic errors
Solution Approach 1:
The patent implements a feedback control system where a metrology tracking system continuously measures the actual position and orientation of the robot end effector, compares it with the commanded position, and feeds back correction signals to compensate for kinematic errors. This closed-loop feedback enables the robot to maintain high manufacturing precision while performing productive manufacturing tasks.
Solution Approach 2:
The patent replaces complex mechanical precision mechanisms with an external metrology tracking system and software-based compensation. Instead of modifying the robot's mechanical structure to improve precision, the system uses optical/laser tracking and computational error compensation to achieve high manufacturing precision.
2Manufacturing precision
If external metrology tracking systems are integrated to improve accuracy, then manufacturing precision is improved, but device complexity increases due to custom controller requirements
Solution Approach 1:
The patent creates a universal interface layer that works with standard industrial robot controllers without requiring custom modifications. The external control system communicates through standardized protocols, making the precision enhancement applicable to multiple robot platforms without increasing individual device complexity.
Solution Approach 2:
The patent introduces an intermediary control system that sits between the metrology tracking system and the robot controller. This intermediary handles the complex coordination and communication, translating tracking data into correction commands that the standard robot controller can execute, thereby isolating the complexity from the robot controller itself.
3Manufacturing precision
If external feedback control is implemented over low-bandwidth interfaces, then manufacturing precision is improved, but reliability deteriorates due to non-deterministic behavior
Solution Approach 1:
The patent performs preliminary synchronization and calibration actions before precision control begins. The system pre-establishes timing relationships, synchronizes clocks between systems, and calibrates coordinate transformations in advance, ensuring that subsequent real-time control operations over low-bandwidth interfaces proceed reliably without timing uncertainties.
Data Source
AI summary
In an industrial robot, an external high-precision metrology tracking system, such as a laser tracker system, is used to directly measure robot kinematic errors and corrections are implemented during processing so that the end effector of the robot may be accurately positioned so that a tool or other object carried by the robot effector can carry out a designated function, such as machining a workpiece or other operation requiring that the effector be accurately positioned with respect to a workpiece.