Piston Load Cell Misalignment Compensation via Strain Gauge Orientation
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Solution Overview
Problem
Existing piston load cells face significant measurement errors due to misalignment, which is complex and requires multiple degrees of freedom compensation, often involving separate and expensive inclination sensors, and lacks effective long-term drift compensation, leading to increased costs and reduced precision.
Innovation Solution
A piston load cell design featuring a deformation body with spherical contact surfaces and two determination means: a first determination means for measuring mechanical deformation and a second determination means for detecting deviations from ideal alignment, using strain gauge sensors aligned at a predefined acute angle to provide comprehensive misalignment compensation without additional inclination sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate inclination sensors are used to compensate misalignment, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the inclination detection function with the existing strain gauge sensors used for load measurement. By strategically orienting strain gauges at specific angles (e.g., 45 degrees) on the deformation body, the same sensor system simultaneously measures both vertical load and inclination, eliminating the need for separate inclination sensors and reducing device complexity while maintaining measurement precision
Solution Approach 2:
The strain gauge sensor system is designed to perform multiple functions: it measures both the vertical load force and the inclination angle of the load cell. This multi-functional approach allows a single sensor system to compensate for misalignment effects without requiring additional dedicated inclination sensing components, thereby reducing overall device complexity
2Measurement precision
If multiple strain gauge sensors are used for comprehensive misalignment detection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent uses a minimal number of strain gauge sensors (e.g., two or four gauges) oriented at specific angles to detect inclination, which is sufficient to compensate for misalignment effects without requiring a full array of sensors in all possible orientations. This partial action approach achieves adequate measurement precision while keeping manufacturing costs low
3Measurement precision
If strain gauge sensors are aligned at predefined angles for inclination detection, then misalignment compensation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent selects specific orientation angles (e.g., 45 degrees relative to the vertical axis) for the strain gauge sensors that optimize the decoupling of load and inclination signals. By carefully choosing these angular parameters, the system achieves effective misalignment compensation while tolerating reasonable manufacturing variations in sensor placement, balancing measurement precision with manufacturing feasibility
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 design enhances precision and reduces costs by providing robust misalignment compensation across multiple degrees of freedom, minimizing measurement errors and drift issues, while maintaining load independence and sensitivity for inclination detection.
Implementation Method 1
a first determination means (9), which converts the mechanical deformation of the deformation body (2) into a signal, and a second determination means (10), which converts a deviation of a central longitudinal axis (8) from the force reference line (6) into a corresponding signal; wherein the first determination means (9) and the second determination means (10) each have at least one strain measurement sensor
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The load cell (1) has a deformation body (2) with an upper contact surface (3) and a lower contact surface (4). The contact surfaces (3, 4) are designed for introducing force into the deformation body (2) and each have a support point (5), wherein the current support points together form a force reference line (6). A columnar region (7) of the deformation body, having a central longitudinal axis (8) and an outer surface line parallel thereto, is arranged between the contact surfaces (3, 4). The load cell (1) further comprises a first determination means (9), which is mounted on the columnar region (7) of the deformation body (2) and converts the mechanical deformation of the deformation body (2) into a signal, and a second determination means (10), which is mounted on the columnar region (7) of the deformation body (2) and converts a deviation of the central longitudinal axis (8) from the force reference line (6) into a signal. The first determination means (9) and the second determination means (10) each have at least one strain sensor. The at least one strain sensor of the second determination means (10) is mounted substantially centrally between the upper contact surface (3) and the lower contact surface (4) and is oriented by a predefined acute angle relative to the outer surface line in such a manner that the signal of the second determination means (10) becomes null if the central longitudinal axis (8) does not deviate from the force reference line (6).