Vision-Guided Drilling End Effector for Robot Arm Misalignment
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Solution Overview
Problem
Articulated robot arms used in aircraft assembly and maintenance for drilling operations face challenges with limited stiffness, causing the drilling tool to bend and move away from the target location, leading to inaccurate drilling, damage, and increased drill bit breakage, and existing correction methods like secondary encoders and laser tracking systems increase complexity and cost.
Innovation Solution
A drilling system that includes a pattern generator to apply a pattern on the workpiece surface, a drilling end effector with a nosepiece and camera to align with the pattern, allowing for precise alignment of the drilling tool with the target location without increasing system complexity or cost, using an existing camera to detect misalignment and adjust accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If articulated robot arms are used for drilling operations, then versatility and flexibility are improved, but stiffness deteriorates causing tool movement away from target location
Solution Approach 1:
The system uses a camera to capture images of a pattern on the workpiece surface, processes these images to detect the position and orientation of the workpiece, and feeds this information back to the control system to adjust the drilling tool's position and orientation, compensating for the robot arm's limited stiffness
Solution Approach 2:
The patent replaces the mechanical stiffness requirement with an optical-mechanical system using a camera to detect workpiece position and orientation, substituting the need for rigid mechanical support with a vision-based compensation approach
2Manufacturing precision
If secondary encoders are mounted on the robot arm to correct tool movement, then drilling precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The system uses a camera to create an optical copy (image) of the workpiece pattern, processes this visual information to determine position and orientation, and uses this data to correct drilling precision without adding physical encoders to the robot arm
3Manufacturing precision
If laser tracking systems are used to correct tool movement, then drilling precision is improved, but calibration complexity and system cost increase
Solution Approach 1:
The patent uses a standard camera and a simple pattern (such as a printed or projected marker pattern) instead of expensive laser tracking systems, achieving comparable precision with significantly lower cost and simpler calibration requirements
4Manufacturing precision
If normality sensors are added to correct tool movement, then drilling precision is improved, but device complexity and cost increase
Solution Approach 1:
The camera serves multiple functions: it detects the workpiece position, determines orientation, and enables precision drilling alignment, replacing the need for separate normality sensors and other correction devices
Data Source
AI summary
A drilling system is provided for drilling a workpiece. The drilling system includes a pattern generator configured to apply a pattern on a workpiece surface of the workpiece at a reference location relative to a target drilling location. The drilling system includes a drilling end effector, which includes a chuck configured to hold a drilling tool. The drilling end effector also includes a nosepiece configured to at least partially surround the drilling tool when the drilling tool is held by the chuck. The nosepiece includes an end portion that is configured to be held on the workpiece surface of the workpiece. The drilling end effector also includes a camera configured to acquire an image of an area of the workpiece surface that includes the pattern. The image acquired by the camera indicates whether the end portion of the nosepiece is aligned with the pattern on the workpiece surface.