Differential Spring Force Sensing for Wearable Muscle Stiffness
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Solution Overview
Problem
Existing wearable measuring devices for skeletal muscle monitoring, such as force sensor and gas pressure sensor wristbands, are prone to measurement distortions due to factors like tightness and muscle bulges, affecting the accuracy of muscle stiffness determination.
Innovation Solution
A wearable measuring device with multiple measuring units, each equipped with a force sensor and a spring unit of differing spring constants, is attached to the body part to detect tension forces, allowing for the estimation of muscle stiffness by analyzing the differential tension forces across these units, thereby minimizing the influence of tightness and muscle bulges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single force sensor wristband is used to monitor skeletal muscle, then the device is simple and easy to wear, but the measurement result is distorted by tightness and muscle bulges
Solution Approach 1:
The measuring device is divided into multiple measuring units (at least two), each with its own force sensor and spring unit. These units are distributed across different regions of the body part, allowing the system to capture differential tension forces that are independent of uniform tightness or muscle bulge effects.
Solution Approach 2:
Each measuring unit is equipped with spring units having different spring constants, creating local variations in mechanical properties. This allows each sensor to respond differently to muscle tension while the differential measurement approach eliminates common-mode disturbances like tightness and bulges.
2Measurement precision
If multiple measuring units with different spring constants are used, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The spring units are designed with different spring constants to create a dynamic response system. This allows the measuring device to adapt to varying muscle tension levels and geometries, improving measurement accuracy across different conditions while maintaining a relatively simple overall structure.
Solution Approach 2:
By varying the spring constant parameter across different spring units, the system achieves differential sensitivity to muscle tension. This parameter differentiation enables accurate muscle stiffness determination while the modular design keeps the overall device complexity manageable.
3Reliability
If the spring units have different spring constants, then the determination of muscle stiffness becomes independent of tightness and bulges, but the calculation complexity increases
Solution Approach 1:
The system uses feedback from multiple force sensors to continuously monitor tension forces in spring units with different spring constants. By comparing these differential measurements, the system can calculate muscle stiffness while compensating for tightness and bulge effects, with results that are independent of these influencing factors.
Solution Approach 2:
The spring units are deliberately designed with asymmetric (different) spring constants rather than uniform values. This asymmetry creates differential responses to muscle tension that, when analyzed together, eliminate the influence of uniform disturbances like tightness and bulges, improving reliability of the stiffness determination.
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 provides a reliable and user-friendly method to determine skeletal muscle stiffness, independent of user-specific or time-dependent factors, ensuring precise and consistent measurement of muscle support needs.
Implementation Method 1
each measuring unit comprises a force sensor and an associated spring unit, with the spring units each having different spring constants
Implementation Method 2
The strength or value of the spring constant of the skeletal muscle varies with the degree of tension in the skeletal muscle
Implementation Method 3
the force sensors are designed to detect the tension force of the associated spring unit
Data Source
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AI summary
The invention relates to a pull-on measuring instrument (12), comprising: a measuring device (14) which has at least two measuring units (16, 18) for monitoring a skeletal muscle (20) of a person; and a holding device (26) for attaching the measuring device (14) to a body part (10), comprising the skeletal muscle (20), of the person. According to the invention: the measuring units (16, 18) each comprise a force sensor (22, 23) and an associated spring unit (24, 25), the spring units (24, 25) differing from one another in their spring constants; the measuring units (16, 18) can be attached to the body part (10) such that the spring units (24, 25) can each be loaded by a different portion of the skeletal muscle (20); and the force sensors (22, 23) are designed to detect a load force of the associated spring unit (24, 25).