Robot Arm Work Position Correction with Multi-Point Error Mapping
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Solution Overview
Problem
Existing work robots face challenges in securing sufficient precision due to uncorrectable errors, such as arm distortion, even when DH parameters are optimized, leading to inaccurate positioning.
Innovation Solution
A work position correction method that sets multiple work points in the robot's movable area and associates spatial coordinate values with correction values, allowing the correction parameter to be reflected on the target position, enabling accurate movement despite errors in the robot arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If DH parameter optimization is applied for coordinate transformation, then the robot can perform coordinate transformation, but sufficient work precision cannot be secured due to uncorrectable errors like arm distortion
Solution Approach 1:
The correction parameter is divided into multiple elements (X, Y, Z coordinates and RX, XY, RZ rotation angles) that can be independently optimized for each work point. This segmentation allows precise correction of different error sources (positioning errors vs. orientation errors) without requiring complex overall transformation, thereby achieving high work precision while maintaining manageable system complexity
Solution Approach 2:
The invention introduces correction parameters that modify the target position and attitude through additive corrections (corrected target position = original target position + correction value). This parameter change approach allows the system to compensate for arm distortion and other errors by adjusting correction values without changing the fundamental coordinate transformation structure, thus improving precision without excessive complexity
2Measurement precision
If multiple work points are set with correction parameters to improve precision, then accurate positioning is achieved, but the calibration process becomes more complex
Solution Approach 1:
The robot performs self-calibration by automatically moving to each work point, measuring its actual position and attitude, and computing correction parameters without external intervention. The control device automatically processes the measurement data and generates the correction parameter table, making the complex calibration process transparent and easy to execute, thus achieving high positioning accuracy while keeping the calibration process manageable
Solution Approach 2:
The system uses measurement feedback from actual robot positions at multiple work points to compute correction parameters. The measured positions are compared with target positions, and the differences are used to determine correction values. This feedback mechanism automatically adjusts the correction parameter to match actual system behavior, improving positioning accuracy while the automated feedback loop simplifies the calibration process
Data Source
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AI summary
A work robot includes a multi-joint type robot arm and an actuator configured to drive each joint of the robot arm, and corrects a designated target position by a correction parameter to operate the robot arm. The correction of the target position is performed by setting multiple work points in a movable area of the robot, setting a correction parameter in which a spatial coordinate value and a correction value are associated with respect to the set multiple work points, and reflecting the set correction parameter on the target position.