Robot Path Correction with VMT® BK
By means of the VMT BK system for path correction, the robot can accurately follow the actual workpiece contour.
The nominal robot path with its support points is applied to a reference workpiece whose contour is designated as nominal. If a new workpiece is introduced, its contour does not match the nominal robot path any more. By measurement on the actual workpiece contour, the path support points are matched to the actual contour. By using the path support points, corrected in this manner, the robot can accurately follow the actual workpiece contour.
In order that the robot is able to measure the workpiece contour, there is a suitable VMT Linerunner Lasersensor installed on its hand. The robot “sees” the workpiece edge with the help of this sensor and can thus determine its relative position on any path support point.
- Seam sealing
- Edge processing
- Soldering and welding
- Processing workpieces
In the first step, the processing contour on the workpiece is measured. To this end, the robot guides a sensor along the processing contour.
Every single support point on the path is corrected on the basis of the measured values.
The robot processes the workpiece using the corrected path.
Many processing tasks require a robot path that is individually adjusted to the workpiece. Not only the position of the workpiece, but each individual processing point on the workpiece must be measured and the robot path correspondingly corrected. The VMT BK system measures the geometry and the position of the seam/joint/edge with an accuracy of 0.1 mm or better and corrects every individual support point of the robot path.
The robot can thus carry out its processing tasks with the highest accuracy.
Integration into the production process
Measuring and processing in one station.
Advantage: saves space in the line.
Separate stations for measurement and processing.
Advantage: No soiling of the measuring equipment, application tool does not need changing.
In a typical application, in a first step, the workpiece position is determined with VMT IS, in order to balance out the position tolerances that are initially present. The measured workpiece displacement is transferred to the robot and there, used as the base displacement of all subsequent movements.
- Can also be used for processes that are sensitive to soiling because of the delay between measurement and processing
- Fine adjustment of the processing path of the robot is possible without influencing the measuring path
- Measurement of edges with a laser triangulation sensor: robust with respect to variable illumination, surface properties and the background
- Autonomous learning of the correct path points and automatic sensor calibration
- Generation of correction values at each support point on the path within the cell or vehicle coordinate system
- Generation of relative correction values with respect to a reference object
- Extensive validation checks for reliable measurement results
- Separate specification of tolerances for each point on the path is possible
- Continuous logging of all system activities internally and at the interfaces to the machine controller and to the robot
- Simple logging for communication with all common industrial robots
- Quality control of the local edge geometry can be carried out at the same time
- Controlling of several robots with one system computer
- Referencing of the object’s edge to an arbitrary point: outer corner, inner corner, centre of sheet, etc.
- Reliable calculation of the edge, even if damaged or soiled
- Self-calibrating after sensor replacement without any additional aids
- Optional: compatible with the VMT 3D position detection unit on the same system computer
VMT® BK Benefits
- Measurement and processing are decoupled
- Highest possible local processing accuracy
- Consistently high manufacturing quality, even for shape fluctuations
- Low consumption of materials for seam sealing
- System is compatible with the VMT 3D position detection unit