Robot-Guided Coating Path Correction for Positioning Tolerances
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Solution Overview
Problem
Current painting systems for motor vehicle body components face inaccuracies due to positioning tolerances in components, robots, and temperature changes, leading to incorrect positioning of coating devices, which existing solutions fail to adequately address, especially in large-area applications and with complex temperature compensation requirements.
Innovation Solution
A coating method that measures the component's edge points using CAD models or direct measurement, adjusts the coating path with correction algorithms, and uses two robots to divide the surface area for precise adaptation, ensuring the measurement movement closely mimics the application movement to compensate for deviations and temperature errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If global component measurement using multiple cameras is used, then the measurement coverage is improved, but the positioning precision deteriorates because component and robot tolerances are not taken into account
Solution Approach 1:
The patent divides the measurement process into two segments: first measuring the component geometry with multiple cameras to obtain the spray surface, then measuring the robot position and temperature deviations separately. This segmentation allows each measurement system to be optimized for its specific purpose, resolving the contradiction between coverage and precision.
Solution Approach 2:
The patent introduces an intermediary coordinate transformation system that maps measurements from the camera coordinate system to the robot coordinate system. This intermediary transformation enables the integration of global component measurement with local robot positioning precision by establishing a reference framework that accounts for both component tolerances and robot tolerances.
2Adaptability or versatility
If mobile robot-guided measurement systems are used, then the measurement flexibility is improved, but the measurement precision deteriorates because only measured areas can be locally compensated
Solution Approach 1:
The patent makes the robot serve multiple functions: it acts as both the painting applicator and the measurement device. The same robot that applies paint is equipped with sensors to measure component geometry and its own position deviations. This multi-functionality ensures that measurement and application follow identical paths under identical conditions, resolving the contradiction between flexibility and precision.
Solution Approach 2:
The robot performs self-measurement of its own position and orientation deviations during the painting process. By using its own sensors to monitor its姿态 and position in real-time, the robot can compensate for its own tolerances without requiring separate measurement equipment, thereby maintaining both flexibility and precision.
3Temperature
If temperature compensation systems with multiple measuring points are used, then the temperature monitoring coverage is improved, but the device complexity deteriorates
Solution Approach 1:
The patent extracts only the essential temperature measurement points needed for robot model compensation, rather than implementing comprehensive temperature monitoring throughout the entire robot structure. By selecting critical measurement locations (such as motor housings and joint areas), the system achieves adequate temperature compensation with minimal sensors, resolving the contradiction between coverage and complexity.
4Measurement precision
If separate measurement processes are used independent of coating paths, then the measurement thoroughness is improved, but the process time deteriorates
Solution Approach 1:
The patent merges the measurement process with the coating process by integrating sensors into the robot system. The robot measures component geometry and its own position deviations during the same motion cycles used for painting, eliminating separate measurement steps. This merging maintains measurement thoroughness while significantly reducing total process time.
Solution Approach 2:
The measurement and coating operations are performed continuously in an uninterrupted sequence using the same robot motion paths. The robot continuously collects measurement data while moving along the coating path, ensuring no idle measurement phases or re-positioning steps are required. This continuous operation maintains measurement quality while minimizing process time.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a method for coating a component (4), e.g. a motor vehicle, using a robot (1, 3) wherein the component (4) is surveyed, for example by means of a camera (5) travelling a measuring path, and wherein deviations from the defined coating path (13, 15) are corrected in light of the survey. The method comprises, in particular, the following steps: (a) specifying at least one coating path (13, 15); (b) specifying reference values of the three-dimensional boundary point positions and/or of the boundary point orientations for boundary points on the edges of the surface region of the component (4); (c) three-dimensionally surveying position, orientation and/or shape of the component (4) to be coated or of a part of the component to be coated by means of a measuring system; (d) determining the variance between the measured values for the boundary point positions and/or the boundary point orientations on the one hand and the reference values of the boundary point positions and/or the boundary point orientations on the other hand; (e) adjusting the coating path (13, 15) as a function of the variance determined; (f) moving an application device (3) along the at least one adjusted coating path (13, 15); and (g) applying the coating agent, particularly a paint, with the application device (3) onto the surface of the component (4) to be coated during movement of the application device (3).