Strain Gauge Full Bridge Circuit Zero Drift Detection
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Solution Overview
Problem
Full bridge circuits with strain gauges face challenges in reliably detecting zero drift, leading to inaccurate load state measurements, particularly in operational conditions, and require redundant circuits that can produce conflicting results due to material expansion differences.
Innovation Solution
An electrical circuit with a strain gauge full bridge, featuring resistor series connections and comparing means to measure voltage potentials at specific taps, allowing for the detection of zero drift independently of load states and enabling monitoring of the full bridge circuit's symmetry and resistor series connections, with temperature compensation to prevent erroneous alarms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant SG full bridge circuits are used to detect zero drift, then reliability of zero drift detection is improved, but device complexity increases and conflicting results may occur due to material expansion differences
Solution Approach 1:
The patent divides the monitoring function into two independent parts: the measurement bridge for load detection and a separate reference bridge for zero drift detection. This segmentation allows each bridge to perform its specific function without interference, eliminating the complexity of redundant measurement bridges while maintaining reliable zero drift monitoring through the dedicated reference bridge that is isolated from mechanical deformations.
Solution Approach 2:
The reference bridge acts as an intermediary element that mediates the zero drift detection function. By introducing this intermediate reference circuit that is mechanically isolated but electrically comparable, the system can detect zero drift without requiring redundant measurement bridges, thus reducing overall system complexity while maintaining detection reliability.
2Ease of manufacture
If monitoring is performed only in unloaded state, then zero drift detection simplicity is improved, but measurement precision deteriorates because operation itself produces signal value different from zero
Solution Approach 1:
The reference bridge is pre-configured during manufacturing to have identical electrical characteristics to the measurement bridge but is mechanically isolated before operation. This preliminary setup establishes a stable reference point that remains valid throughout operation, allowing zero drift detection to be performed accurately in any state without requiring complex real-time calibration or unloaded state monitoring.
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 reliable detection of zero drift during operation, reduces the need for redundant circuits, and extends maintenance intervals, enhancing the accuracy and cost-effectiveness of load state monitoring in applications like crane systems.
Implementation Method 1
Full bridge circuits comprising SG (strain gauge) elements may be used to determine load states at mechanically deformable elements
Implementation Method 2
a first resistor series connection connected between the terminals of an energy supply gate of the strain gauge full bridge circuit and having a first tap between two resistors; a second resistor series connection connected between the terminals of a signal gate of the strain gauge full bridge circuit and having a second tap between two resistors
Data Source
AI summary
An electrical full bridge strain gauge circuit, load cell, and load detection device for use in lifting platforms such as forklifts, loaders, cranes, and trucks, wherein the detection of the weight of a given load is desirable. The circuit includes a full bridge strain gauge configuration having a pair of voltage supply terminals and a pair of signal terminals, first resistors connected in series between the supply terminals and having a first tap between two resistors, and second resistors connected in series between the signal terminals and having a second tap between two resistors. A comparer has input terminals connected to the first and the second taps, for comparing a first voltage potential at the first tap with a second voltage potential at the second tap, and for producing a corresponding drift signal.