Robot Motion Segmentation for Fast Settling Laser Cutting
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Solution Overview
Problem
Aggressive robot motion in laser cutting operations leads to excessive tool jerk at stop locations, necessitating longer settling times, which increases cycle time and requires labor-intensive cycle tuning.
Innovation Solution
The method involves segmenting robot movement into multiple segments with varying accelerations, maintaining optimal acceleration in most segments while reducing it in the last segment to minimize tool jerk and stabilize the robot more quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aggressive robot motion is used to reduce cycle time, then productivity is improved, but tool jerk increases causing excessive vibration and longer settling time
Solution Approach 1:
The robot movement is divided into multiple segments with different acceleration characteristics. The method segments the motion profile into at least two portions: a first portion with higher acceleration to maintain productivity, and a second portion with reduced acceleration to minimize tool jerk and vibration before stopping. This segmentation allows the system to achieve both fast cycle times and reduced settling requirements.
2Stability of the object's composition
If robot speed is reduced during movement to minimize tool vibration, then tool jerk is reduced, but cycle time increases
Solution Approach 1:
The acceleration profile is made non-uniform across different segments of the movement. Instead of applying a single speed reduction throughout the entire movement, the method applies reduced acceleration only in the final segment where it is most effective for minimizing tool jerk. The earlier segments maintain higher acceleration to preserve productivity, creating a locally optimized solution.
3Manufacturing precision
If settling time is extended to reduce tool jerk, then cut quality is improved, but cycle time increases
Solution Approach 1:
The method performs preliminary action by reducing acceleration in the final movement segment before the tool comes to rest. This proactive reduction in acceleration during the approach phase minimizes the generation of tool jerk in advance, allowing the tool to settle more quickly upon arrival. The settling time is reduced because the harmful vibrations are prevented rather than corrected after they occur.
4Manufacturing precision
If labor intensive cycle tuning is performed to optimize move patterns, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The method changes the acceleration parameter dynamically across different movement segments. By implementing a segmented acceleration profile where the controller automatically adjusts acceleration values for different portions of the movement, the system achieves optimized cut quality without requiring complex manual programming. The parameter change is systematic and rule-based, reducing the need for labor-intensive iterative tuning.
Data Source
AI summary
A system and method for controlling movement of a robot holding a tool from an end of one tool operation to a beginning of a next tool operation that reduces tool jerk and thus reduces the robot stabilization time. The method includes separating the robot movement into a plurality of segments that have different robot movement accelerations, determining an acceleration of the robot for each segment that optimizes a cycle time of the robot movement, and reducing the optimal acceleration of the robot during a last segment so as to reduce tool jerk when the robot reaches the beginning of the next tool operation. In one non-limiting embodiment, the tool is a laser cutting tool and the number of segments is seven segments.