6-Axis Robot Posture Calibration Using Axis Position Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The calibration process for a 6-axis robot is complex and time-consuming due to the need to measure angles and rotate axes to calibrate the origin position, particularly for the fifth axis, which complicates the adjustment of the robot's posture and overall calibration.
Innovation Solution
A method that involves specifying axis central positions and planes for three axes perpendicular to the robot mounting surface, determining angle adjustments based on these positions, and using a laser tracker to measure and correct initial errors, allowing for efficient adjustment of the robot's posture by calculating and eliminating angular errors through specific rotational joint adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods are used to calibrate the origin position of the fifth axis, then calibration accuracy can be achieved, but the calibration process becomes complex and time-consuming
Solution Approach 1:
The calibration process is segmented into two distinct phases: (1) a simplified initial error adjustment phase that quickly corrects major angular errors using a laser tracker and calculated adjustment amounts, and (2) a subsequent detailed calibration phase. This segmentation allows the time-consuming detailed calibration to be performed after a rapid initial adjustment, thereby reducing total calibration time while maintaining accuracy.
Solution Approach 2:
The method performs preliminary error adjustment before full calibration by measuring the actual positions of axis central points and calculating angle adjustment amounts. This preliminary action corrects significant initial errors using a laser tracker and mathematical calculations, preparing the robot for more efficient subsequent calibration operations and reducing the time required for the complete calibration process.
2Manufacturing precision
If multiple rotation and measurement steps are performed to calibrate the fifth axis, then accurate origin position calibration is achieved, but the work becomes complicated and difficult to perform quickly
Solution Approach 1:
The method replaces complex mechanical rotation and alignment operations with optical measurement using a laser tracker. Instead of manually rotating axes and measuring angles with physical instruments, the laser tracker optically measures the positions of axis central points, and a computer calculates the required angle adjustments, substituting mechanical complexity with optical-electronic measurement and computational analysis.
Solution Approach 2:
The method changes the calibration approach by measuring actual positions of axis central points and computing angle adjustment amounts rather than following fixed mechanical rotation procedures. This parameter-based approach uses coordinate measurements and mathematical calculations to determine corrections, simplifying the operational process while maintaining calibration accuracy.
3Measurement precision
If detailed measurement and rotation procedures are followed for fifth axis calibration, then calibration accuracy is improved, but overall robot posture adjustment becomes more complex
Solution Approach 1:
The method uses a laser tracker as a universal measurement tool that can measure the positions of axis central points for multiple axes (first, fourth, and fifth axes) without requiring different measurement instruments or procedures. This multi-functional approach simplifies the calibration process by using a single device for all positional measurements, reducing procedural complexity while maintaining measurement precision.
Solution Approach 2:
The invention introduces a computer as an intermediary that receives coordinate information from the laser tracker, calculates the angle adjustment amounts using mathematical algorithms, and outputs the correction values. This intermediary processing step automates the complex calculations and coordinate transformations, reducing the complexity of manual computations and making the calibration process more systematic and manageable.
Data Source
AI summary
A method of adjusting a posture of a 6-axis robot standing in a direction perpendicular or substantially perpendicular to a robot mounting surface includes specifying axis central positions of three axes located at different heights in the direction perpendicular or substantially perpendicular to the robot mounting surface of the 6-axis robot, specifying two planes including two arcs of which rotation centers are represented by two axes farther away from the robot mounting surface among the three axes, specifying a position of a predetermined point on the arc farther away from the robot mounting surface among the two arcs, and determining an angle adjustment amount of the three axes in a rotation direction and an angle adjustment amount of an axis extending between the two axes in a rotation direction based on the specified axis central positions of the three axes, the specified two planes, and the specified position of the predetermined point.