Robotic Drill Head Self-Centering for Template Hole Alignment
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Solution Overview
Problem
Existing robotic drilling systems face challenges in achieving accurate alignment between the drill head and the hole in a drill template, particularly due to metrology errors and positional inaccuracies, which can lead to binding issues and inefficiencies in peg-in-hole operations.
Innovation Solution
A robotic drill system equipped with a tool head featuring an expandable collet and an end effector, where the expandable collet expands between a retracted configuration for insertion and an expanded configuration to center the end effector within the hole, allowing for corrected alignment and preventing binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a robotic system uses standard sensors and actuators for peg-in-hole operations, then the system cost is reduced, but the alignment accuracy between drill head and hole deteriorates due to metrology errors and positional inaccuracies
Solution Approach 1:
The system dynamically changes the diameter parameter of the expandable collet during operation. The collet starts with a smaller diameter for insertion, then expands to a larger diameter for precise centering and alignment, allowing low-cost robotic systems to achieve high alignment accuracy without requiring expensive high-precision components throughout the entire system
Solution Approach 2:
The expandable collet transitions from a static component to a dynamic one that can change its dimensions during operation. This dynamic adjustment enables the system to compensate for positioning errors and achieve accurate alignment even with lower-cost robotic hardware
2Manufacturing precision
If the robotic system increases system stiffness with larger and more expensive robots, then the alignment accuracy is improved, but the practicality for mobile robotic drilling systems deteriorates due to localization error and drill template registration error
Solution Approach 1:
The expandable collet performs self-centering by expanding within the hole to automatically find and maintain the correct alignment position. This self-service mechanism eliminates the need for expensive high-stiffness robotic systems, making mobile robotic drilling practical while maintaining high alignment accuracy
3Ease of operation
If the retracted diameter of the expandable collet is made smaller to facilitate insertion, then the ease of insertion is improved, but the ability to center the end effector in the hole deteriorates
Solution Approach 1:
The expandable collet dynamically changes its diameter from a smaller retracted state during insertion to a larger expanded state for centering. This dynamic transformation allows the same component to fulfill both functions: easy insertion when retracted and precise centering when expanded
Data Source
AI summary
A robotic drill system and a method of drilling with a robotic drill system. This includes inserting a tool head of the robotic drill within a hole of a drill template along an initial insertion trajectory with a robotic manipulator arm that is moved by at least one robotic actuator for causing robotic insertion of the tool head. In response to sensing binding of the tool head to a wall of the hole while inserting the tool head along the initial insertion trajectory, the disclosure includes stopping robotic insertion of the tool head and activating a self-centering device of the tool head to reorient the tool head to a corrected alignment of the tool head axis relative to the hole. The self-centering device may include an expandable collet.