Robot Controller Sensitivity Analysis for Positioning Accuracy
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Solution Overview
Problem
Existing methods for improving the positioning accuracy of articulated robots are hindered by the need for a large number of error parameters, which are interrelated and difficult to preset effectively, leading to challenges in achieving accurate calculations of the reference point position.
Innovation Solution
A robot controller that includes a position information acquisition unit, a parameter storage unit, a sensitivity calculation unit, a target selection unit, and a parameter correction unit, which calculates sensitivity values for error parameters, selects correction targets based on these values, and corrects the error parameters to enhance positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of error parameters are used to compensate for positioning errors, then positioning accuracy is improved, but device complexity and difficulty of parameter determination increase significantly
Solution Approach 1:
The patent extracts only the essential error parameters that have significant impact on positioning accuracy, separating them from the large number of less important parameters. This is achieved through sensitivity analysis that identifies which parameters contribute most to positioning errors, allowing the system to focus correction efforts on a smaller subset of critical parameters while ignoring less significant ones.
Solution Approach 2:
The patent changes the approach from using all error parameters to using a selectively reduced set of parameters. By transforming the complete error parameter set into a simplified subset based on sensitivity analysis, the system maintains positioning accuracy while reducing complexity. The parameter correction unit then adjusts only these selected parameters based on actual positioning errors.
2Measurement precision
If all error parameters are treated as unknown variables, then comprehensive error compensation is possible, but the number of measurements required becomes extremely large
Solution Approach 1:
The patent applies partial action by correcting only the most significant error parameters rather than all parameters. The sensitivity analysis identifies a subset of parameters that, when corrected, provide the majority of positioning accuracy improvement. This allows the system to achieve sufficient accuracy with fewer measurements and less time, without attempting to determine all error parameters.
Solution Approach 2:
The patent segments the error parameters into different groups based on their sensitivity and impact on positioning accuracy. The parameter correction unit focuses on correcting the high-sensitivity parameters first, while less sensitive parameters are either corrected with lower priority or ignored. This segmentation allows efficient error compensation without requiring determination of all parameters.
3Loss of time
If preset parameter groups are used for error correction, then the number of measurements required is reduced, but positioning accuracy depends heavily on the suitability of the preset groups
Solution Approach 1:
The patent makes the error parameter selection dynamic rather than static. Instead of using fixed preset parameter groups, the system dynamically determines which parameters to correct based on sensitivity analysis performed on the actual robot system. This dynamic selection adapts to the specific characteristics and usage conditions of the robot, ensuring both efficiency and accuracy.
Solution Approach 2:
The patent incorporates feedback mechanisms where the positioning accuracy is continuously monitored and used to refine the selection of error parameters for correction. The sensitivity analysis is performed based on actual positioning errors and system characteristics, creating a feedback loop that optimizes which parameters are corrected and how, ensuring both time efficiency and high accuracy.
Data Source
AI summary
According to the present invention, provided is a robot control device that can improve relatively easily the positioning accuracy of a robot. A robot control device according to one aspect of the present disclosure comprises: a position information acquisition unit which acquires position information indicating the actual position of a reference point at the end of a robot having a plurality of drive shafts; a parameter storage unit which stores a plurality of error parameters used to calculate the accurate position of the reference point from a command value for the robot; a sensitivity calculation unit which calculates a sensitivity value representing the magnitude of the change amount of the calculated position of the reference point with respect to the change amount for each error parameter; a target selection unit which selects, on the basis of the sensitivity value, an error parameter to be corrected by the parameter correction unit; and a parameter correction unit which corrects the error parameter to be corrected on the basis of the command value for the robot and the position information, assuming that error parameters other than the error parameter to be corrected do not affect the position of the reference point.