Differential Force Sensor Structure for Environmental Drift Compensation
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Solution Overview
Problem
Displacement detection type force sensors face challenges in accurately detecting force and moment components across multiple axes due to variations caused by environmental factors like temperature and humidity, leading to drift in detection values.
Innovation Solution
A force-detection structure with differential detecting sections that detect relative movement and rotation between end portions using signals in reverse phase, canceling out signal variations from environmental changes, allowing precise detection of force components across three axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a displacement detection type force sensor uses conventional detection methods to detect force and moment components, then the detection structure is simple, but the detection values drift due to environmental factors such as temperature and humidity
Solution Approach 1:
The detection structure is segmented into multiple detecting sections (first detecting section, second detecting section, third detecting section), each responsible for detecting specific force or moment components. This segmentation allows independent optimization of each section and enables the use of differential measurement techniques to eliminate environmental interference while maintaining overall system reliability.
Solution Approach 2:
The patent introduces a differential detection mechanism as an intermediary between the applied force and the detection output. By using differential pairs of detecting elements and processing their signals differentially, the system mediates the measurement process to cancel out common-mode environmental effects while preserving the force-related signals.
2Measurement precision
If the detecting part uses a simple structure to detect displacement, then the device complexity is low, but the detection precision deteriorates due to signal variations from environmental changes
Solution Approach 1:
Each detecting section is designed with specific local qualities optimized for its detection function. The first detecting section uses a specific electrode arrangement for detecting force components, the second section uses a different arrangement for moment components, and the third section is optimized for its specific detection task. This local optimization enables high measurement precision in each section while maintaining overall system manageability.
Solution Approach 2:
The patent extends the detection from single-axis to multi-axis detection by adding detecting sections in different spatial dimensions. The first detecting section detects components in one dimension, the second section detects components in another dimension, and the third section detects additional components, thereby achieving comprehensive three-dimensional force and moment detection without excessive complexity in any single detecting element.
3Reliability
If conventional detection methods are used without differential measurement, then the device complexity is low, but the detection values are affected by environmental factors causing drift
Solution Approach 1:
The differential detection system implements a form of feedback by continuously comparing the signals from paired detecting elements. The differential processing mechanism provides real-time compensation for environmental variations by using the signal from one element as a reference to correct the signal from its paired element, thereby maintaining detection stability without requiring complex external feedback control systems.
Solution Approach 2:
The patent converts the harmful effect of environmental variations into a beneficial differential signal. By arranging detecting elements in pairs and processing their signals differentially, the system causes environmental effects to appear as common-mode signals that cancel out in the differential output, while the force-related signals appear as differential-mode signals that are preserved and enhanced. This transforms environmental interference from a harmful factor into a cancelable artifact.
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 approach enhances the accuracy and precision of force and moment component detection by isolating signal variations caused by environmental factors, ensuring that detected values accurately represent displacements due to applied forces.
Implementation Method 1
A plurality of pairs of electrodes are respectively arranged at predetermined locations in the gap in such a manner that the electrodes of each pair are opposed to each other in a direction of any one axis of a three-axis rectangular coordinate system, so as to form capacitance between the opposing electrodes of each pair
Implementation Method 2
a first differentially-detecting section that detects, in a differential manner, a relative movement between the first end portion and the second end portion along the first axis as first movement data by using signals mutually reverse in phase
Implementation Method 3
a connecting portion that elastically connects the first end portion to the second end portion; a detecting part that detects a relative displacement between the first end portion and the second end portion, accompanied by elastic deformation of the connecting portion
Data Source
AI summary
A displacement detection type force-detection structure. The force-detection structure includes a first end portion; a second end portion; a connecting portion elastically connecting the first and second end portions with three degrees of freedom; a detecting part detecting relative displacement between the first and second end portions accompanied by elastic deformation of the connecting portion. The detecting part includes a first differentially-detecting section detecting a relative movement between the first and second end portions along a first axis as first movement data by using signals reverse in phase; a second differentially-detecting section detecting a relative movement between the first and second end portions along a second axis as second movement data by using signals reverse in phase; and a third differentially-detecting section detecting a relative rotation between the first and second end portions about a central axis along a third axis as rotation data by using signals reverse in phase.