Wheatstone Bridge Assembly with Auxiliary Circuits for Offset Compensation
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Solution Overview
Problem
Existing electronic bathroom scales with Wheatstone bridge assemblies suffer from variability in weight estimation due to unequal load cell measurements and user offset, requiring additional Wheatstone bridges and user intervention, leading to increased energy consumption and imprecision in offset estimation.
Innovation Solution
A weighing device with a Wheatstone bridge assembly comprising four load cells arranged in parallel branches with symmetrical auxiliary circuits, controlled by an electronic control unit to estimate weight and offset without user intervention, reducing components and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two separate Wheatstone bridges are used to estimate user offset, then offset estimation capability is improved, but energy consumption increases due to requiring two amplifiers
Solution Approach 1:
The patent merges the functionality of two separate Wheatstone bridges into a single bridge configuration. The four load cells are arranged in one Wheatstone bridge with auxiliary circuits that can selectively short-circuit resistors, allowing the system to obtain both weight and offset information from a single bridge and one amplifier, thereby reducing energy consumption while maintaining offset estimation capability.
Solution Approach 2:
The single Wheatstone bridge assembly is designed to perform multiple functions: it can measure total weight, estimate user offset, and provide ballistocardiography signals. By making the bridge assembly multi-functional, the patent eliminates the need for separate bridges and amplifiers for different measurement types, reducing overall energy consumption.
2Adaptability or versatility
If four Wheatstone bridges are used to exploit user offset for interaction, then interaction capability is improved, but production cost increases
Solution Approach 1:
The patent combines the functionality of four separate Wheatstone bridges into a single bridge assembly with auxiliary circuits. This single assembly can provide offset information in multiple directions and support various interaction modes, dramatically reducing component count and production cost while maintaining versatility for user interaction applications.
Solution Approach 2:
The single Wheatstone bridge assembly is designed to be multi-functional, capable of measuring weight, estimating offset in multiple directions, and providing ballistocardiography signals. This universal design enables diverse user interactions without requiring multiple separate bridge assemblies, thereby reducing manufacturing complexity and cost.
3Reliability
If conventional Wheatstone bridge assembly is used, then weight measurement is achieved, but weight estimation varies due to user offset and assembly imperfections
Solution Approach 1:
The patent uses the output signal from the Wheatstone bridge to calculate user offset, then uses this offset information to compensate for measurement errors in the weight estimation. This feedback mechanism allows the system to correct for both user positioning errors and assembly imperfections, improving weight measurement reliability and precision.
Solution Approach 2:
The patent changes the electrical parameters within the Wheatstone bridge by selectively short-circuiting resistors through auxiliary circuits. By varying the bridge configuration and measuring output signals under different conditions, the system can separately determine weight and offset parameters, then use this information to improve weight estimation accuracy and compensate for assembly imperfections.
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
The solution allows precise weight and offset estimation without user intervention, enabling dynamic interaction and improved energy efficiency, while reducing production costs and enhancing precision in offset estimation.
Implementation Method 1
the load cells being combined in a Wheatstone bridge type of assembly
Implementation Method 2
each load cell comprising at least two resistors
Data Source
AI summary
A weighing device of the electronic bathroom scale type, includes four feet, each fitted with a load cell, each load cell including two resistors combined in a Wheatstone bridge type of assembly to define a first axis of symmetry and a second axis of symmetry, the assembly further including at least one auxiliary circuit configured to selectively short-circuit two resistors belonging to the same foot or to two neighboring feet in the bathroom scale, the first auxiliary circuit being symmetrical relative to the first axis or the second axis, the assembly being controlled by an electronic control unit to estimate a weight and to estimate an offset of a user on the bathroom scale.