Tunnel Boring Machine Strain Sensor Error Correction
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Solution Overview
Problem
Tunnel boring machines face measurement errors when strain sensors are mounted on rotational parts like the cutter head due to rotational movement, leading to inaccurate force measurements, which can result in damage to the cutter head and abnormal wear.
Innovation Solution
A tunnel boring machine design that includes a cutter head, a cutter support, a rotational angle sensing unit, and a data processing unit that corrects strain measurement data using error data obtained from current and past corresponding measurement values at specific rotational angles, effectively addressing the cyclic measurement errors caused by rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain sensor is mounted on the rotational parts such as a cutter head, then the cutter thrust force can be measured directly, but the measurement value includes error occurring along with the rotation
Solution Approach 1:
The system performs preliminary actions by storing past measurement values corresponding to each rotational angle before needing to correct current measurements. The data processing unit accumulates historical strain sensor data at specific rotational angles, enabling subsequent error correction by comparing current measurements with previously stored values from the same rotational position, thus preparing the correction mechanism in advance.
Solution Approach 2:
The system implements feedback by using past measurement values to correct current measurement errors. The data processing unit compares the current strain sensor measurement with the stored past measurement value at the corresponding rotational angle, calculates the error, and applies this error correction to obtain accurate cutter thrust force data, creating a closed-loop error compensation system.
2Productivity
If strain measurement values are used to calculate cutter thrust force, then direct measurement is achieved, but cyclic measurement errors occur due to rotation
Solution Approach 1:
The system performs preliminary actions by storing past measurement values corresponding to each rotational angle before needing to correct current measurements. The data processing unit accumulates historical strain sensor data at specific rotational angles, enabling subsequent error correction by comparing current measurements with previously stored values from the same rotational position, thus preparing the correction mechanism in advance.
Solution Approach 2:
The system implements feedback by using past measurement values to correct current measurement errors. The data processing unit compares the current strain sensor measurement with the stored past measurement value at the corresponding rotational angle, calculates the error, and applies this error correction to obtain accurate cutter thrust force data, creating a closed-loop error compensation system.
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 approach allows for more accurate measurement of the force acting on the cutter head by suppressing measurement errors associated with rotation, thereby preventing damage and wear, and ensuring precise data correction based on recent and relevant measurement values.
Implementation Method 1
a strain sensor provided in the cutter head or the cutter support
Data Source
AI summary
The tunnel boring machine includes a data processing unit configured to obtain error data (Er) based on a current measurement value (Vp) of the strain sensor obtained at a current angle (θ) of the cutter head and a past corresponding measurement value (Vo) obtained at a corresponding angle corresponding to the current angle, to correct the current measurement data using the error data.