Force Sensor Sensitivity Balance via Elastic Deformation
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Solution Overview
Problem
Conventional force sensors face challenges in balancing the detection sensitivity between moment and force in a three-dimensional orthogonal coordinate system, leading to inaccuracies due to differences in capacitance values for each axis, particularly with moment detection being sensitive to distance from the center of rotation, making it difficult to design sensors with optimal sensitivity ratios for various applications.
Innovation Solution
A force sensor design featuring an elastically deformed portion connected to a force receiving body with base portions fixed to a supporting body, allowing for adjustable drag forces to balance sensitivity, using a structure with arm-like portions and relay points to selectively prevent deformation based on external forces, enabling easier adjustment of moment-to-force sensitivity ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional force sensors use a basic structure body with deformation bodies to detect force and moment, then the sensor can detect force in each coordinate axis and moment around each coordinate axis, but the detection sensitivity between moment and force cannot be balanced, leading to inaccuracies in moment detection
Solution Approach 1:
The deformation body is divided into multiple independent deformation portions (first deformation portion and second deformation portion), each responsible for detecting different components (force and moment). This segmentation allows independent optimization of each portion's structural parameters to achieve balanced detection sensitivity across different measurement types.
Solution Approach 2:
Different structural characteristics are assigned to different parts of the deformation body. The first deformation portion has specific geometric features optimized for force detection, while the second deformation portion has different geometric features optimized for moment detection. This local differentiation enables each portion to excel at its specific detection function while maintaining overall system balance.
2Device complexity
If the sensor structure is simplified to reduce dimensions and cost, then the sensor becomes more compact and economical, but it becomes difficult to independently detect force for each coordinate axis with optimal sensitivity
Solution Approach 1:
The deformation body serves multiple detection functions simultaneously. By strategically placing deformation portions and detection elements, a single deformation body structure enables detection of both force and moment components, reducing the need for separate dedicated structures for each measurement type while maintaining detection capability for all six degrees of freedom.
Solution Approach 2:
The force receiving body and supporting body are connected through an integrated deformation body that combines multiple deformation portions. This merging of structural elements reduces the total component count and assembly complexity while preserving the ability to independently measure force and moment through the coordinated deformation of different portions.
3Measurement precision
If moment detection sensitivity is increased by adjusting the distance from the center of rotation, then moment detection capability improves, but force detection sensitivity becomes unbalanced and noise amplification occurs
Solution Approach 1:
The geometric parameters of the deformation portions are independently optimized. The first deformation portion has dimensional parameters tuned for force detection sensitivity, while the second deformation portion has parameters tuned for moment detection sensitivity. This parameter differentiation allows each portion to operate at its optimal sensitivity level without causing noise amplification in other measurement channels.
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 design allows for flexible adjustment of detection sensitivity between moment and force, reducing noise amplification and improving accuracy by selectively exerting drag forces, thereby enhancing the sensor's performance across different applications.
Implementation Method 1
a deformation body which connects the force receiving body with the supporting body to yield at least partially elastic deformation upon exertion of force or moment
Implementation Method 2
a representative detection element which is of a displacement detection type in the latter is a capacitive element which is constituted with a displacement electrode fixed at a specific site of a deformation body and a fixed electrode fixed at a part opposite to a supporting body. When displacement occurs on the deformation body upon exerted force, a distance between the displacement electrode and the fixed electrode is changed, by which the displacement is electrically detected as change in capacitance value of the capacitive element
Data Source
Figure 1(a)~1(c)
Figure 2~3
Figure 4~5
AI summary
A plate-like supporting body (200) is arranged below a plate-like force receiving body (100) and a deformation body (300) is connected between them. The deformation body (300) is provided with an elastically deformed portion (310) arranged along a connection channel (R1) which connects a first force receiving point (P1) with a second force receiving point (P2), a first base portion (320) and a second base portion (330) which support the elastically deformed portion (310) from below. The upper end of the first base portion (320) supports the vicinity of a first relay point (m1) on the connection channel (R1) so as to sway freely, and the upper end of the second base portion (330) supports the vicinity of a second relay point (m2) on the connection channel (R1) so as to sway freely. An arm-like member (312) which couples a pair of relay points (m1, m2) is used to lower the detection sensitivity of moment around an origin (O) which is exerted on the force receiving body (100), thereby easily adjusting the balance of detection sensitivity between moment and force.