Laser Sensor Calibration for Robot Elasticity Error Compensation
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Solution Overview
Problem
Existing robot systems face challenges in accurately identifying non-geometric parameters due to limitations in local measurement principles, leading to significant errors in absolute accuracy, particularly from unaccounted elasticity, which conventional methods fail to comprehensively address.
Innovation Solution
A method using a laser sensor system to project radiation patterns through a robot's workspace, detecting these patterns on a light-sensitive sensor, and iteratively correcting robot structure information by comparing detected and computed positions to compensate for non-geometric errors, employing a computation unit with model-based parameter identification and machine learning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If local measurement methods are used to identify robot parameters, then device complexity and cost are reduced, but measurement precision deteriorates due to algebraic dependencies that prevent comprehensive identification of non-geometric parameters
Solution Approach 1:
The patent transitions from local measurement (one-dimensional point-to-point comparison) to global measurement using laser trackers and theodolites that capture three-dimensional spatial coordinates of multiple points simultaneously. This dimensional expansion enables comprehensive identification of non-geometric parameters by observing robot behavior from multiple spatial perspectives, thereby resolving the algebraic dependencies that limit local methods.
Solution Approach 2:
The patent employs a globally measuring system that serves multiple functions: it measures geometric parameters, identifies non-geometric parameters, characterizes elasticity effects, and validates robot model accuracy. This multi-functional approach replaces the need for separate measurement systems, making the complex measurement process manageable while achieving comprehensive parameter identification.
2Measurement precision
If globally measuring systems like laser trackers are used to identify non-geometric parameters, then measurement precision improves, but device complexity and acquisition costs increase significantly
Solution Approach 1:
The patent divides the measurement process into distinct phases: geometric parameter measurement using simple tools, followed by non-geometric parameter identification using global measurement systems. This segmentation allows the complex task to be broken down into manageable steps, where the expensive global measurement system is used only when necessary for identifying non-geometric parameters, rather than for all measurements.
Solution Approach 2:
The patent changes the measurement parameters from simple point-to-point distances to comprehensive three-dimensional spatial coordinates captured by laser trackers and theodolites. This parameter transformation enables the system to capture elastic deformations and non-geometric effects that are invisible to conventional local measurement methods, thereby achieving precise identification of previously unmeasurable parameters.
3Device complexity
If conventional measurement methods are used, then device complexity remains low, but reliability deteriorates because elastic deformations and non-geometric errors cannot be comprehensively identified and compensated
Solution Approach 1:
The patent implements a feedback mechanism where the globally measuring system captures actual robot positions, compares them with model-predicted positions, and uses the deviations to identify and compensate for non-geometric parameters and elastic deformations. This closed-loop feedback process continuously refines the robot model, thereby improving reliability and absolute accuracy while maintaining manageable system complexity.
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 effectively identifies and corrects non-geometric errors, enhancing the absolute accuracy of robot operations by iteratively refining model parameters, reducing operational inaccuracies caused by elasticity.
Implementation Method 1
at least one radiation pattern generator configured to emit at least one radiation pattern by the at least one radiation pattern generator through the working space of the robot, the at least one radiation pattern including at least one laser beam or at least one laser light plane
Implementation Method 2
at least one sensor with at least one light-sensitive surface is arranged on the effector of the robot
Data Source
AI summary
A method for compensating non-geometric error influences on the absolute accuracy of a robot using a laser sensor system includes projecting at least one radiation pattern through the workspace, and selecting the measurement configurations such that, for at least one elasticity element, there is at least one pair of measurement configurations in which the absolute value of the difference in torques acting on the at least one elasticity element is greater than a threshold value. A deviation on a light-sensitive surface of at least one sensor) from a straight line and/or plane, which is implicitly defined by the radiation pattern, its direction and orientation, is taken into account by comparing the measured projection position with a calculated projection position based on faulty robot structure information. The corrected robot structure information is then derived to compensate for the non-geometric error influences.