Forearm Activity Estimation via Torque and Power
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Solution Overview
Problem
Current devices for measuring physical activity, particularly of the upper limb, face challenges in reliability due to noisy and poorly exploited measurements from inertial and magneto-inertial sensors, which limits their performance and accuracy in estimating energy expenditure and muscular efforts.
Innovation Solution
A method that determines the orientation of the forearm using inertial measurement units placed between the elbow and wrist, incorporating a linear or nonlinear state estimator filter, and calculates torque exerted by muscles based on angular velocity and physical parameters to estimate physical activity, with the option to compare the estimated energy with predetermined thresholds for identifying muscular problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inertial measurement units are used to measure physical activity, then measurement capability is provided, but measurement precision deteriorates due to noisy and poorly exploited measurements
Solution Approach 1:
The patent transforms the raw sensor measurements (acceleration, angular velocity) into meaningful physical parameters (torque, power, energy) through mathematical modeling and integration. This parameter transformation resolves the contradiction by converting noisy raw data into precise physiological metrics that accurately represent upper limb physical activity.
Solution Approach 2:
The patent introduces intermediate computational steps (state estimator filter, torque calculation, power integration) between the raw sensor measurements and the final physical activity estimates. These intermediaries act as mediators that process and refine the noisy measurements into reliable and precise output metrics.
2Loss of information
If magneto-inertial techniques are used, then orientation and movement data are obtained, but device complexity increases due to additional sensors and processing requirements
Solution Approach 1:
The patent combines inertial measurement units with magnetometer data and integrates multiple sensor inputs into a unified processing framework. This merging approach resolves the contradiction by consolidating multiple information sources into a single coherent system that reduces overall complexity while maintaining complete movement information.
Solution Approach 2:
The patent creates a multi-functional processing system that simultaneously extracts orientation, angular velocity, torque, power, and energy information from the same sensor inputs. This universal approach resolves the contradiction by making the sensor system perform multiple functions without requiring separate dedicated sensors for each measurement type.
3Measurement precision
If state estimator filters are implemented, then noise filtering is achieved, but computational processing time increases
Solution Approach 1:
The patent applies state estimator filters in a preliminary processing stage to clean and prepare sensor data before subsequent torque and power calculations. This preliminary action resolves the contradiction by performing noise filtering early in the processing chain, which reduces the computational burden on later stages and optimizes overall processing time.
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 reliability of physical activity measurement by filtering noise and providing a representative estimate of energy expenditure, enabling effective identification of muscular issues.
Implementation Method 1
acquisition by inertial measurement means integral with a forearm of said upper limb of an angular velocity of said forearm
Implementation Method 2
the determination of the orientation of the forearm includes the implementation of a linear or nonlinear state estimator filter
Implementation Method 3
estimation by data processing means of a torque exerted by the muscles of an arm of the upper limb on said forearm as a function of the measured angular velocity
Implementation Method 4
determining a power exerted by the upper limb as a function of the estimated torque and the measured angular speed
Data Source
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AI summary
The present invention relates to a method for estimating the physical activity exerted by an upper limb (10) of a person (1), the method being characterised in that it comprises the steps of: (a) acquiring, by inertial measurement means (20) rigidly attached to a forearm (11) of said upper limb (10) of said person (1), an angular speed of said forearm (10); (b) estimating, by data-processing means (21, 31, 41), a torque exerted by the arm muscles (12) of the upper limb (1) on said forearm (11) as a function of the measured angular speed, of an orientation of said forearm (11) and of physical parameters of said forearm (11); (c) determining, by a data-processing means (21, 31, 41), a power exerted by the upper limb (10) as a function of the estimated torque and of the measured angular speed.