Conveyor-Robot Calibration Using Shared Measuring Points
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Solution Overview
Problem
The existing systems for calibrating conveyor and robot systems require complex recalibrations due to changes in robot positions or transport position determination devices, involving multiple position determinations to synchronize component-fixed and conveyor-based coordinate systems, which is inefficient and time-consuming.
Innovation Solution
A method that determines the positions of at least three measuring points using a robot, allowing for the calibration of both conveyor and robot coordinate systems with fewer measurements, and enables precise transformations between these systems, reducing the need for extensive recalibration by averaging multiple measurements and using relative transformations between robots and conveyor bases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position of at least three measuring points is determined for each robot and component-fixed coordinate system, then the calibration accuracy is improved, but the number of measurements and calibration complexity increases significantly
Solution Approach 1:
The calibration process is segmented into two parts: first calibrating the conveyor-based coordinate system using three measuring points, then determining robot coordinate systems relative to this established conveyor system. This segmentation reduces the overall complexity by breaking down the multi-robot, multi-coordinate system calibration into manageable stages.
Solution Approach 2:
The conveyor-based coordinate system is established in advance as a reference framework before calibrating individual robot coordinate systems. This preliminary action provides a stable foundation that simplifies subsequent robot calibrations, as robots can be calibrated relative to the already-established conveyor system rather than requiring complete recalibration of all coordinate systems.
2Reliability
If complete recalibration is performed after replacing a robot or modifying transport position detection device, then the system synchronization accuracy is maintained, but the time and resources required increase
Solution Approach 1:
The conveyor-based coordinate system is established in advance as a stable reference framework. When robots are replaced or detection devices are modified, only the affected robot's coordinate system needs recalibration relative to this pre-established conveyor system, rather than performing complete system-wide recalibration.
Solution Approach 2:
The conveyor-based coordinate system serves as a master reference that can be copied or referenced by multiple robots. When a robot is replaced, its coordinate system can be determined by referencing the existing conveyor-based system and the new robot's position relative to it, rather than requiring complete recalibration of all systems.
3Manufacturing precision
If multiple coordinate system transformations are calculated for m robots and n component-fixed coordinate systems, then the precision of robot-component interaction is improved, but the computational complexity and measurement requirements increase
Solution Approach 1:
The coordinate transformation process is segmented into two stages: first establishing the conveyor-based coordinate system transformation, then determining robot-specific transformations relative to this conveyor system. This segmentation reduces the overall computational complexity by breaking down the multi-robot, multi-coordinate system transformations into hierarchical stages.
Solution Approach 2:
The conveyor-based coordinate system acts as an intermediary reference framework between the conveyor system and individual robots. Instead of directly transforming between every robot and every component-fixed coordinate system, transformations are mediated through the conveyor-based system, reducing the total number of transformation calculations required.
Data Source
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AI summary
The invention relates to a method for calibrating a system with a conveying means (30), e.g. conveyor belt, a first robot (10), a transport position-determining means (40), e.g. rotary encoder or camera, and with a measuring point system (W1) transported on the conveying means (30), e.g. component having at least three measuring points (Pi,j). The passing of the component (W1) is detected by the transport position-determining means (40) and established as a synchronisation position. The position of the three measuring points (Pj,j) of the component (W1) is detected by the first robot (10) in a first transport position (δa) or at a first distance from the synchronisation position. The position of one of these measuring points (Pj,j) is detected by the first robot (10) in a second transport position (δb). The position of two or one of these measuring points (Pj,j) is detected by a second robot (20) in a third or fourth transport position (δc, δd). The calibration occurs in that, from the measurements of the measuring points (Pj,j) and the distances from the synchronisation position (δa, δb, δc, δd), the coordinate systems (R1, R2, C1, C2, W1) are formed in relation to the first (10) and the second (20) robot, the conveying means basis in terms of each of the two robots, and the component (W1), and the transformations (TR 1 C1, TC1 W11, TR2,C2, TC2; W12) between the coordinate systems are determined.