Servo-Actuated Robot Drilling Clamp for Accurate Hole Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Robotic drilling systems face positional and orientation accuracy issues due to kinematic, compliance, and backlash errors, and clamping mechanisms can cause inaccuracies and damage to workpieces, especially in high-precision applications like aerospace.
Innovation Solution
A clamp with a servo motor-driven actuation mechanism and force sensor for controlled clamping, combined with a C-shaped frame and non-slip surface, is attached to the drilling tool, allowing precise and accurate positioning and force application, and a metrology system for bias correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pneumatically actuated clamp is used to hold the drilling tool against the workpiece, then the drilling tool is secured in position, but the high pressure forces the drill out of its intended position and may damage the workpiece
Solution Approach 1:
The clamp transitions from pneumatic actuation to servo motor actuation, changing the control parameter from high pressure to controlled force. The force sensor provides feedback to maintain optimal clamping force, preventing excessive pressure that would cause positioning errors while ensuring reliable holding stability.
Solution Approach 2:
A force sensor is integrated into the clamp to provide real-time feedback on the clamping force applied to the workpiece. This feedback loop allows the control system to adjust the servo motor output to maintain the optimal clamping force, preventing both insufficient holding and excessive pressure that would damage the workpiece or cause positioning errors.
2Force
If a pneumatically actuated clamp applies high pressure to secure the drilling tool, then the tool is held firmly, but positioning errors occur and workpiece damage may result
Solution Approach 1:
The clamp system changes from pneumatic high-pressure actuation to servo motor actuation with force sensor feedback. This allows precise control of the clamping force parameter, maintaining sufficient holding force while preventing excessive pressure that would cause the drill to shift from its intended position.
Solution Approach 2:
The pneumatic actuation system is replaced with a servo motor-driven mechanical system. This substitution enables more precise control over the clamping force application, replacing the inherently high-pressure pneumatic system with a controllable electrical-mechanical system that can apply force more accurately.
3Measurement precision
If robotic arm encoders provide feedback for positioning, then reasonable accuracy is achieved, but kinematic errors, compliance errors, and backlash errors still occur
Solution Approach 1:
A force sensor is introduced as an intermediary element between the robotic arm and the workpiece. This sensor provides real-time measurement of the interaction forces, allowing the control system to compensate for compliance errors and maintain accurate positioning despite the inherent limitations of robotic arm encoders.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces positional errors and maintains accuracy by applying controlled clamping forces and using bias corrections, enhancing the precision and reliability of robotic drilling operations.
Implementation Method 1
a force sensor arranged to measure a force acting on the workpiece contacting portion in the drilling direction
Implementation Method 2
an actuation mechanism comprising a servo motor configured to drive linear movement of the frame relative to the drilling tool
Implementation Method 3
The workpiece contacting portion may have a non-slip surface for contacting the workpiece surface. The non-slip surface may for example comprise a rubber layer or coating.
Data Source
AI summary
A clamp for a robotic drill and related method and system for robotic drilling of a component. The clamp attaches to a drilling tool of a robotic drill. The clamp includes: an attachment portion configured for attachment to the drilling tool; a frame linearly moveable relative to the attachment portion along a central axis of the clamp parallel to a drilling direction of the drilling tool; an actuation mechanism including a servo motor configured to drive linear movement of the frame relative to the drilling tool; a workpiece contacting portion at a distal end of the frame, including a surface for contacting a surface of a workpiece to be drilled and an aperture allowing for passage of a drill bit of the drilling tool through to the workpiece surface; and a force sensor arranged to measure a force acting on the workpiece contacting portion in the drilling direction.