Robot Workspace Boundary Speed Control via Dynamic Braking Distance
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Solution Overview
Problem
Existing robot control methods fail to ensure safe braking within designated workspaces without unnecessarily restricting the workspace, leading to potential violations of protected areas and inconsistencies in process quality due to variable speed reductions.
Innovation Solution
The method involves planning and pre-controlling the robot's path speed to reduce the distance to the workspace boundary, ensuring a safe braking distance is maintained, allowing the robot to come to a standstill within the workspace limits by optimizing the speed profile based on braking distances and secondary conditions like maximum speeds and accelerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a braking zone with guaranteed safe distance is provided between monitored work area and protection area, then safety is improved, but workspace area is reduced and device complexity increases
Solution Approach 1:
The patent applies dynamics by making the speed limit dynamically adjustable based on the robot's position relative to the workspace boundary. Instead of a static braking zone, the system continuously calculates position-dependent speed limits that allow the robot to operate at higher speeds when far from boundaries and automatically reduce speed when approaching boundaries, eliminating the need for a fixed reduced workspace area.
Solution Approach 2:
The system performs preliminary action by calculating and preparing position-dependent speed limits in advance based on the robot's current position and planned trajectory. The controller proactively adjusts speed limits before the robot reaches critical distances from boundaries, enabling smooth deceleration without abrupt stops and maintaining optimal workspace utilization.
2Reliability
If override control reduces speed in critical cases, then safety is improved, but process quality deteriorates due to variable speed reductions
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the speed parameter based on the robot's position relative to workspace boundaries. The controller calculates position-dependent speed limits that smoothly vary with distance from boundaries, allowing process parameters (like laser energy or adhesive dosing) to be adjusted proportionally with speed, thereby maintaining constant process quality while ensuring safety through controlled deceleration.
3Manufacturing precision
If constant speed is maintained for process quality, then manufacturing precision is improved, but safety is compromised when approaching workspace boundaries
Solution Approach 1:
The system resolves this contradiction by making the speed dynamic rather than constant. The controller continuously adjusts the speed limit based on the robot's real-time position relative to workspace boundaries, allowing constant speed (and thus constant process quality) to be maintained when the robot is safely far from boundaries, while automatically reducing speed when approaching boundaries to ensure safe stopping distance.
4Loss of time
If switching actions are triggered with negative time shift, then process timing is adjusted, but switching precision deteriorates due to speed variations
Solution Approach 1:
The patent applies feedback by continuously monitoring the robot's actual position and speed, then using this information to dynamically adjust speed limits and switching triggers. The system calculates position-dependent speed limits and adjusts switching actions based on real-time feedback rather than fixed time shifts, compensating for speed variations and maintaining precise switching timing even when speed changes are required for safety.
Data Source
AI summary
The method involves projecting a predetermined tracking speed of a robot by reducing a distance to a border line of a work room in a reduced manner, when braking of the robot within the border line of the room reaches a downtime. The robot is digitally moved with the predetermined tracking speed in such a manner that a braking distance associating a displacement state is smaller than a distance of an effector or a tool center point from the border line of the room. The braking distance in a path point is determined during path planning and based on the displacement state of the robot.