Manipulator Origin Calibration Using 3D Anchor Point Measurement
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Solution Overview
Problem
Current methods for calibrating robot origins often require moving the robot to a manufacturer or specific environment, leading to increased time, cost, and reduced efficiency due to the need for re-teaching points after calibration.
Innovation Solution
An origin calibration method for manipulators using a 3D measuring device in the work environment to measure reference and actual anchor points, calculate a Jacobian matrix, and update the rotation angle to compensate for offset origins, allowing for instant calibration without re-teaching points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the robot is moved to original manufacturer or certain environment for calibration, then the calibration accuracy can be ensured, but the time and cost increase and work efficiency reduces
Solution Approach 1:
A laser tracker is introduced as an intermediary measurement device to enable calibration in the work station environment. The laser tracker serves as a mediator between the manipulator and the calibration process, providing precise 3D coordinate measurements without requiring transport to the manufacturer's calibration environment.
Solution Approach 2:
The traditional mechanical transport and re-teaching system is replaced with an optical measurement system (laser tracker). Instead of physically moving the robot and manually re-teaching points, the patent uses laser-based 3D coordinate acquisition and Jacobian matrix calculations to achieve calibration in-situ.
2Measurement precision
If the robot is moved to original manufacturer or certain environment for calibration, then the calibration can be performed properly, but the cost increases
Solution Approach 1:
The laser tracker acts as a cost-effective intermediary that provides manufacturer-level calibration capabilities within the customer's work station, eliminating the need for expensive transport and external calibration services.
Solution Approach 2:
The manipulator performs calibration autonomously using the laser tracker and reference ball system. The self-service calibration process eliminates the need for external calibration services, reducing dependency on original equipment manufacturers and associated costs.
3Measurement precision
If the robot is moved back to work station after calibration, then the calibration is completed, but the manipulator needs to be taught points again which reduces work efficiency
Solution Approach 1:
The laser tracker is pre-positioned in the work station and reference balls are pre-placed at known locations before calibration is needed. This preliminary setup enables rapid calibration execution without requiring subsequent re-teaching operations, as the coordinate system transformation is calculated automatically through Jacobian matrix operations.
Solution Approach 2:
The calibration process maintains continuous operational capability by performing calibration in-situ without removing tools or interrupting the work flow. The manipulator remains attached to tools throughout calibration, and the coordinate transformation is applied continuously to maintain positioning accuracy.
4Measurement precision
If the traditional calibration method is used, then the origin can be calibrated, but the device complexity and operation difficulty increase due to moving and re-teaching requirements
Solution Approach 1:
The laser tracker and reference ball system serve as intermediaries that simplify the calibration operation. Instead of complex manual re-teaching procedures, the system automatically acquires 3D coordinates and calculates the Jacobian matrix to determine the origin offset, making the process more straightforward and less error-prone.
Data Source
AI summary
An origin calibration method of a manipulator is provided. The origin calibration method includes steps of: (a) controlling the manipulator to move in accordance with a movement command, and acquiring the 3D coordinates of the reference anchor points reached by the manipulator; (b) controlling the manipulator to move in accordance with the movement command while an origin of the manipulator being offset, acquiring the 3D coordinates of the actual anchor points reached by the manipulator, and acquiring a Jacobian matrix accordingly; (c) acquiring a deviation of a rotation angle of the manipulator according to the Jacobian matrix, the 3D coordinates of the reference anchor points and the actual anchor points, and acquiring a compensation angle value according to the deviation; and (d) updating the rotation angle of the manipulator according to the compensation angle value so as to update the origin of the manipulator.