Robotic Laser Head Mounting to Decouple Wrist-Axis Rotation
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Solution Overview
Problem
The rotational movement of laser heads about the 6th axis in multi-axis robots compromises the robot's dynamics and speed, leading to positioning errors and increased tool center control length, while also complicating the replacement and reconfiguration of end effectors, which results in higher machine-idle time and costs.
Innovation Solution
A multi-axis robot configuration where the laser head is rotationally uncoupled from the rest of the end-of-arm tooling, allowing it to be mounted on the hand and not rotatable about the 6th axis, reducing inertia and enabling faster movement with a compact footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the laser head is mounted on the distal end of the robotic forearm and rotates about the 6th axis with the end-of-arm tooling, then the laser beam can be trained at any desired position within the process space, but the rotational movement of the laser head compromises the robot's dynamics and speed, leading to positioning errors and increased tool center control length
Solution Approach 1:
The system is divided into two independent rotational components: the end-of-arm tooling (EOAT) that rotates about the 6th axis for tool orientation, and the laser head that rotates independently about its own axis (7th axis) for beam direction control. This segmentation allows each component to perform its specific function without compromising the other's precision and dynamics.
Solution Approach 2:
A rotational coupling mechanism acts as an intermediary between the EOAT and the laser head. This intermediary allows the laser head to rotate independently while maintaining its mounting on the EOAT, enabling the laser beam to be directed at any position within the process space without requiring the entire EOAT assembly to rotate.
2Adaptability or versatility
If the laser head rotates about the 6th axis with the end-of-arm tooling, then the laser can follow the profile of the workpiece, but the rotational movement leads to inertia thus resulting in robot-generated positioning error and deviation from the desired path
Solution Approach 1:
The rotational functions are segmented into two independent axes: the 6th axis for EOAT orientation and the 7th axis for laser head rotation. This allows the laser head to follow workpiece profiles by rotating on its own axis without adding inertia to the 6th axis rotation, thereby maintaining path accuracy and eliminating robot-generated positioning errors.
Solution Approach 2:
The laser head rotation about the 7th axis is designed to be dynamically independent from the EOAT rotation about the 6th axis. This dynamic separation allows the laser head to quickly adjust its orientation to follow workpiece profiles without the inertial effects that would result from rotating the entire EOAT assembly, ensuring reliable path following accuracy.
3Measurement precision
If the laser head is mounted on the end-of-arm tooling that rotates about the 6th axis, then the laser can be positioned correctly, but various industrial robots require large complex cable and hose bundles around the robot lower arm and wrist, and the protection of the laser head from mechanical hazards is problematic
Solution Approach 1:
The system segments the rotational functions so that only the EOAT rotates about the 6th axis, while the laser head rotates independently about the 7th axis. This reduces the complexity of cable and hose routing since the laser head's rotation is on a smaller, more localized axis, and the EOAT rotation can accommodate standard cable management solutions without requiring large complex bundles throughout the entire arm structure.
4Power
If the laser head is mounted on the end-of-arm tooling, then the laser processing can be performed, but the laser head adds to the footprint of the end-of-arm tooling which can be a significant disadvantage since the work space is often too small limiting the robot's effective maneuverability
Solution Approach 1:
The laser head is designed to nest within or alongside the EOAT structure when not in use, and rotates on a compact 7th axis that does not significantly increase the overall footprint of the end-of-arm tooling. This allows the laser processing capability to be integrated without substantially increasing the space required, maintaining the robot's effective maneuverability in confined workspaces.
Data Source
AI summary
A multi-axis robot includes multiple arms. The last arm which is closest to the workpiece has a tip or wrist which is configured to receive an end-of-arm tooling (EOAT) rotatable about the 6th axis of the robot. A mount for supporting a laser head assembly is coupled to the wrist so that the laser head assembly is not rotatable about the 6th axis of the robot.