Robotic CMM Alignment Using Common Coordinate References
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Solution Overview
Problem
Coordinate measuring machines face inefficiencies and operational degradation due to the need for precise pre-defined positioning and orientation of workpieces, as well as potential calibration issues, which limits their adaptability and automation capabilities.
Innovation Solution
A system comprising a coordinate measuring machine, a workpiece storage apparatus, and a robotic arm with a controller that defines a common coordinate system, allowing the robotic arm to automatically orient and place workpieces within the measuring machine's measuring space using reference geometry tools and kinematic locators, enabling precise positioning without requiring pre-defined spacing and orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If workpieces are manually positioned and oriented in pre-defined locations on the CMM table, then measurement accuracy is maintained, but operational efficiency and automation capability deteriorate
Solution Approach 1:
The system uses self-contained kinematic locators and reference geometry tools that automatically establish coordinate transformations without requiring manual positioning expertise. The robotic arm autonomously performs workpiece retrieval, orientation, and placement based on pre-programmed routines, eliminating the need for operators to manually position workpieces in pre-defined locations while maintaining measurement accuracy through automated coordinate system transformations.
Solution Approach 2:
The system dynamically adjusts coordinate system parameters through automated transformation calculations. The controller computes transformation matrices between the robotic arm's coordinate system and the CMM's measuring space coordinate system based on measured reference geometry, enabling the system to adapt to different workpiece positions and orientations automatically rather than requiring fixed pre-defined locations.
2Reliability
If workpieces are placed in pre-defined positions and orientations, then measurement reliability is ensured, but system adaptability deteriorates
Solution Approach 1:
The system transitions from static pre-defined positioning to dynamic adaptive positioning. The robotic arm can place workpieces in various locations within its workspace, and the controller dynamically calculates the necessary coordinate transformations in real-time based on the actual workpiece position and orientation, maintaining measurement reliability while significantly improving system adaptability.
Solution Approach 2:
The kinematic locators and reference geometry tools serve multiple functions: they establish coordinate systems for both the robotic arm and CMM, enable automated workpiece handling, and provide measurement reference points. This multi-functionality allows the system to handle various workpiece types and positions universally without requiring separate pre-defined positioning procedures for each case.
3Manufacturing precision
If manual alignment and positioning procedures are used, then setup precision is achieved, but automation extent and throughput deteriorate
Solution Approach 1:
The system replaces manual mechanical alignment procedures with automated robotic manipulation and computational coordinate transformations. The robotic arm, controlled by a computer program, performs all positioning and orientation operations, while the controller automatically calculates transformation matrices to ensure setup precision, completely eliminating the need for manual alignment operations.
Solution Approach 2:
The system performs preliminary coordinate system definition and transformation matrix calculation automatically before workpiece measurement begins. The robotic arm pre-positions workpieces according to pre-programmed routines, and the controller pre-computes the necessary coordinate transformations, enabling seamless automated measurement operations without requiring manual intervention during the measurement process.
4Measurement precision
If CMM requires precise calibration and workpiece positioning, then measurement accuracy is maintained, but operational complexity and time consumption increase
Solution Approach 1:
The system maintains continuous automated operation by seamlessly integrating robotic workpiece handling with CMM measurement operations. The robotic arm continuously retrieves and positions workpieces while the CMM continuously performs measurements, with automated coordinate transformations ensuring seamless coordination between the two operations, eliminating idle time and manual intervention delays.
Solution Approach 2:
The controller acts as an intermediary that automatically coordinates between the robotic arm's positioning operations and the CMM's measurement operations. It manages the coordinate system transformations, timing synchronization, and operation sequencing, enabling both subsystems to work together efficiently without requiring separate calibration and positioning time for each workpiece.
Data Source
AI summary
Embodiments provide measurement systems having a coordinate measuring machine, a workpiece storage apparatus, and a robot for delivering workpieces from the workpiece storage apparatus to the coordinate measuring machine, and methods for orienting and operating such systems. Illustrative embodiments employ a reference geometry tool on the robotic arm, and kinematic locators on the coordinate measuring machine and/or on the workpiece storage apparatus to define a coordinate system common to the coordinate measuring machine, the workpiece storage apparatus, and the robot.