Bending Machine Calibration via Optical Transformation Matrix
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Solution Overview
Problem
Existing methods for determining the bending angle in bending machines are prone to inaccuracies due to changes in the relative position between the bending angle measuring device and the machine, leading to incorrect bending angles, especially when material fluctuations occur and vibrations affect the measuring device.
Innovation Solution
A calibration method that uses a machine-fixed first coordinate system and a bending angle measuring device with an illumination device and image capturing system to determine the current bending angle by analyzing a light pattern on a reference feature, generating a transformation matrix to correct for positional deviations and ensure accurate bending angle determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bending angle measuring device is installed in the working area to monitor the bending angle, then the bending angle can be determined during the bending process, but the relative position between the measuring device and the machine may change due to vibrations or sheet metal impact, leading to measurement inaccuracies
Solution Approach 1:
A calibration process is performed before actual bending operations to establish the initial coordinate transformation between the machine coordinate system and the measuring device coordinate system. This preliminary calibration creates a reference transformation matrix that compensates for installation tolerances and ensures accurate measurements throughout the bending process.
Solution Approach 2:
The system continuously monitors the bending angle during the bending process and compares it with the target angle. The measured bending angle is fed back to control the bending process, allowing real-time adjustments to achieve the desired bending angle despite material parameter fluctuations.
2Device complexity
If the bending angle measuring device is made small and light for compact installation, then the device can be easily integrated into the machine, but it becomes more susceptible to position changes from vibrations
Solution Approach 1:
The patent replaces heavy mechanical measurement systems with a compact optical measuring device that uses light patterns and image capture to determine bending angles. This substitution enables a smaller, lighter device that is easier to integrate while maintaining measurement accuracy through software-based coordinate transformation and calibration.
3Ease of manufacture
If the coordinate system assignment is established during machine setup, then the initial calibration is simplified, but any subsequent changes in relative position cause incorrect bending angles
Solution Approach 1:
The system performs a preliminary calibration process during machine setup that captures the initial coordinate transformation between the machine coordinate system and the measuring device coordinate system. This preliminary action creates a reference transformation matrix that is used throughout operation to maintain accuracy despite subsequent position changes.
Solution Approach 2:
The system dynamically adjusts the coordinate transformation parameters based on the calibration data. By changing the transformation matrix parameters to account for actual installed positions, the system maintains measurement accuracy without requiring complex mechanical adjustments or repositioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures accurate monitoring and calibration of the bending angle, compensating for installation tolerances and maintaining correct bending angle determination throughout the process, thereby ensuring reproducible and precise bending operations.
Implementation Method 1
an illumination device (9) of the bending angle measuring device (1) emits a light pattern (10) onto a surface of a sheet metal part (18)
Implementation Method 2
the image of the light pattern on the sheet metal surface is captured by an image capturing device (11) of the bending angle measuring device (1)
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to calibration procedures for a bending machine with a bending angle measuring device (1), wherein the bending machine is assigned a machine-fixed first coordinate system (15), and wherein, during the execution of a bending operation, the bending angle measuring device determines the current actual bending angle. In a calibration process, a light pattern (10) is emitted by the illumination device (9) onto a reference feature (6) of the bending machine or the bending tool arrangement (2), and the image acquisition device (11) captures the image of the light pattern (10) at the reference feature (6). The evaluation module (12) determines a reference point (13) of the reference feature (6) from the captured image, which reference point (13) is defined in the first coordinate system (15).Furthermore, the evaluation module (12) determines a transformation matrix (17) from the coordinates of the reference point (13) in the first coordinate system and a second coordinate system permanently assigned to the bending angle measuring device (1), which is transmitted to a machine control of the bending machine and taken into account by it in the bending model of the bending forming process.