Thread Parameter Measurement Using Optical Sensor and Axes Transformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing measurement methods for threaded objects, particularly in the hydrocarbon industry, face challenges in precision and repeatability due to misalignment issues, limiting the ability to accurately measure parameters like taper, run-in, and run-out, and requiring costly and impractical on-machine alignment.
Innovation Solution
A non-contact measurement method using a device with optical sensors and a computer-controlled mechanical system that performs scanning operations to calculate an axes transformation matrix, allowing for absolute measurements of thread parameters regardless of misalignment, and providing precise location of the object in space without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If on-machine alignment is performed to achieve precise measurement, then measurement precision is improved, but manufacturing time increases and device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining at least one trajectory of the optical sensor on the threaded object before measurement. This trajectory is predetermined based on the object's geometry and measurement requirements, allowing the sensor to automatically follow the correct path without requiring manual alignment or positioning adjustments during the measurement process. This eliminates the need for time-consuming on-machine alignment while maintaining measurement precision.
2Device complexity
If non-contact measurement is used to avoid physical contact, then device complexity is reduced, but measurement precision deteriorates due to misalignment
Solution Approach 1:
The patent replaces mechanical alignment systems with an optical measurement system that uses computer-controlled mechanical movement to guide the sensor. Instead of relying on physical contact or mechanical alignment fixtures, the system uses optical sensors to capture thread geometry data while a computer controls the sensor's movement along pre-defined trajectories. This substitution eliminates misalignment issues inherent in mechanical alignment while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary computational layer that processes optical sensor data to determine the object's position and orientation in space. The computer system acts as an intermediary between the optical sensor and the measurement results, calculating transformation matrices that account for any misalignment between the sensor coordinate system and the object's actual position. This intermediary computation enables precise measurement regardless of initial alignment conditions.
3Measurement precision
If measurement is performed on the threading machine, then alignment precision is improved, but productivity decreases due to parallel process limitation
Solution Approach 1:
The patent enables measurements to be performed after the threading operation is complete, using pre-defined sensor trajectories that are independent of the threading machine's position. This allows the measurement process to occur in parallel with subsequent manufacturing operations, eliminating the bottleneck where measurement must wait for the piece to be removed from the lathe. The preliminary definition of measurement trajectories ensures that accurate measurements can be taken without requiring the piece to be repositioned or realigned.
4Ease of operation
If manual alignment is performed after removing the piece from the lathe, then measurement can be performed, but alignment precision deteriorates significantly
Solution Approach 1:
The patent replaces manual alignment operations with an automated optical measurement system that uses computer-controlled positioning. Instead of requiring an operator to manually align the piece with mechanical fixtures, the system uses optical sensors to automatically capture the object's geometry and computes the necessary transformation matrices to account for any positioning errors. This substitution maintains ease of operation (the piece can be measured after removal from the lathe) while eliminating the precision loss associated with manual alignment.
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
Enables accurate and repeatable measurement of thread characteristics such as taper, seal diameter, and ovality, allowing for precise alignment corrections and improving manufacturing quality control by avoiding misalignment issues, thus enhancing the precision and efficiency of the measurement process.
Implementation Method 1
at least one optical sensor adapted to retrieve the shape of the threaded object
Data Source
AI summary
A measurement method for thread parameters for a threaded object (3), by means of a measurement device (1) defining a spatial reference system (X, Y, Z) incorporating an optical sensor (5) to retrieve the shape of the threaded object, and defining a spatial reference system (X′, Y′, Z′), the measurement device (1) having a computer to assemble a first matrix that describes the quadratic form representing the threaded object in the spatial reference system (X, Y, Z), thus providing the relationship between the two spatial reference systems. The method comprises the steps of:a) predefining at least one trajectory of the at least one optical sensor (5) on the threaded object, along which measurement points are selected such that the matrix evaluated on these values satisfies the condition that it has maximum rank,b) performing a first scanning operation by the at least one optical sensor (5) along said at least one trajectory and retrieving data of the predefined measurement points,c) feeding these data to the first matrix and calculating an axes transformation matrix relating the first spatial reference system with the second spatial reference system for defining the relative position of the threaded object with respect to the second spatial reference system,d) using the axes transformation matrix to convert all data retrieved from the second spatial reference system to the first spatial reference system.