Portable CMM Serial Bus Capture Eliminates Wire Warping
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Solution Overview
Problem
Conventional portable coordinate measuring machines face challenges in achieving high accuracy due to thermal and load-induced warping, resulting in reduced precision and increased weight, making them bulky and less effective compared to non-portable machines.
Innovation Solution
The development of a portable coordinate measuring machine with a shoulderless shaft and housing design, utilizing serial communication for data transmission, and employing steel or controlled expansion alloys for structural elements to maintain thermal stability, along with a rotary damper assembly for counterbalancing and torque detection, enhances precision and reduces weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional portable coordinate measuring machines use traditional capture wires and bulky structural designs, then they can achieve basic measurement functionality, but their accuracy is reduced due to thermal and load-induced warping, and their weight increases making them less portable
Solution Approach 1:
The patent removes the dedicated capture wire from the system entirely, replacing it with a serial communication interface. This extraction eliminates the physical constraint that limited accuracy while adding weight, allowing the machine to achieve higher measurement precision without the ballast of traditional wiring harnesses.
Solution Approach 2:
The patent changes the communication paradigm from electrical signal transmission through capture wires to digital serial communication. This parameter change in the signal transmission method enables more accurate angle signal capture without the physical bulk and thermal sensitivity of traditional wire-based systems.
2Measurement precision
If conventional portable coordinate measuring machines use improved accuracy components, then measurement precision increases, but the machine becomes bulky and heavy
Solution Approach 1:
The patent extracts the capture functionality from physical wire infrastructure and relocates it to a digital communication protocol. This removes the bulk associated with traditional capture wire routing and housing, achieving improved accuracy without increasing machine volume.
Solution Approach 2:
The patent replaces the mechanical/electrical capture wire system with a digital serial communication system. This substitution eliminates the need for physical capture wire pathways and associated structural support, reducing machine size while improving measurement precision through more accurate digital signal transmission.
3Loss of information
If conventional portable coordinate measuring machines use traditional capture wire systems, then they can transmit angle signals, but the capture accuracy is limited and the system complexity increases
Solution Approach 1:
The patent extracts the angle signal capture function from the physical capture wire and embeds it within the existing serial communication protocol. This eliminates the need for separate capture wire infrastructure while improving angle signal accuracy, and actually reduces system complexity by consolidating communication functions.
Solution Approach 2:
The patent makes the serial communication interface multi-functional, using it both for general data transmission and for precise angle signal capture. This universal usage eliminates the need for dedicated capture wires, improving angle signal accuracy while reducing overall system complexity by consolidating communication pathways.
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
This solution achieves significantly improved accuracy and reduced weight, allowing for precise measurements over a wide temperature range while maintaining portability, thus surpassing the limitations of conventional portable coordinate measuring machines.
Implementation Method 1
employing steel or controlled expansion alloys for structural elements to maintain thermal stability
Implementation Method 2
employing a rotary damper assembly for counterbalancing and torque detection
Data Source
AI summary
A portable coordinate measurement machine (CMM) includes a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments and a plurality of rotary joints. At least one of the rotary joints from the plurality of rotary joints includes first and second bearings, a shaft configured to rotate about an axis of rotation of the first bearing and the second bearing, at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft about the axis of rotation, and a serial communication circuit configured to receive via serial communication a capture command.