Force Detection Apparatus Linearity Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Force detection apparatuses struggle to provide a linear relationship between force and force signal values across all ranges due to differences in permittivity and deformation characteristics of air and cushion layers, resulting in an inflection point and non-linear detection.
Innovation Solution
A force detection apparatus with a force detector and controller that calculates force signal values using a product of force and constants in two distinct ranges, adjusting the relationship to achieve linearity by using a product of force threshold and constants in each range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cushion layer is provided between the first conductor and the second conductor in addition to the air layer, then the detection apparatus can detect strong force when the air layer thickness reaches zero, but the relationship between force and force signal value becomes non-linear due to different permittivity and deformation characteristics of air and cushion layer
Solution Approach 1:
The patent divides the force detection range into two distinct ranges: a first range where only the air layer deforms and a second range where both the air layer and cushion layer deform. By segmenting the detection ranges and applying different linearization methods for each range, the patent resolves the contradiction between detecting strong force and maintaining measurement linearity across the entire force spectrum.
Solution Approach 2:
The patent changes the calculation parameters based on the force range. In the first range, it uses a first linearization parameter set, while in the second range, it uses a second linearization parameter set. This dynamic parameter adjustment allows the system to maintain linear relationship between force and force signal value across different deformation conditions of the air and cushion layers.
2Measurement precision
If only the air layer exists between the first conductor and the second conductor, then the force detection apparatus can detect weak force with high precision, but the apparatus cannot detect strong force when the air layer thickness reaches zero
Solution Approach 1:
The patent introduces a cushion layer beforehand to prevent the air layer thickness from reaching zero under strong force conditions. This cushion layer acts as a protective element that maintains a minimum separation distance between the conductors, enabling continuous detection of strong force while preserving the high precision detection capability for weak force through the air layer.
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 ensures a linear relationship between force and force signal values across the entire range, improving detection accuracy by correcting the signal values based on predetermined constants and thresholds.
Implementation Method 1
a force detection apparatus that detects force on the basis of change of capacitance between a first conductor and a second conductor
Implementation Method 2
permittivity of the air layer and permittivity of the cushion layer are different
Implementation Method 3
the cushion layer is elastically deformed according to the force
Data Source
AI summary
A force detection apparatus includes: a force detector that includes an electrode and a conductor facing the electrode across a first and a second layers and outputs a force signal value before correction; and a force detection controller outputting a force signal value after correction having a linear relationship with a force. In a first range of force in which the first layer is deformed and the second layer is not deformed, the force detection controller calculates the force signal value after correction, based on a product of the force and a first constant. In a second range of force in which the first and second layers are deformed, the force detection controller calculates the force signal value after correction, based on a sum of a product of a threshold and the first constant and a product of a difference between the force and the threshold and a second constant.