Force Estimation via Myoelectric Sensors and Posture Analysis
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Solution Overview
Problem
It is challenging to accurately determine the force applied at a point of action in production processes without directly measuring it, as attaching force-measuring devices can interfere with the work and muscle tension does not necessarily reflect the applied force.
Innovation Solution
An information processing apparatus that estimates the force applied at a point of action by combining data from a camera for posture analysis, myoelectric potential sensors, and acting force meters, using a musculoskeletal model to correlate posture, applied forces, and muscle activity to calculate the required force without direct measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force-measuring device is attached to the point of action to directly measure the applied force, then measurement precision is improved, but the work process is interfered with and device complexity increases
Solution Approach 1:
The patent uses myoelectric potentials as an intermediary to indirectly estimate muscle force. Instead of directly measuring force at the point of action (which interferes with work), the system measures electrical signals from muscle surfaces and uses a musculoskeletal model to calculate the corresponding forces, thus obtaining measurement data without attaching devices to the point of action.
Solution Approach 2:
The patent replaces the mechanical force-measuring device with an electrical measurement system. By substituting mechanical force sensors with myoelectric potential sensors and computational modeling, the system eliminates the need for physical attachment at the point of action while still enabling force measurement through electrical signal analysis.
2Ease of operation
If muscle tension is measured to estimate applied force, then non-invasive measurement is achieved, but measurement precision deteriorates because muscle tension does not necessarily reflect applied force
Solution Approach 1:
The patent implements an iterative feedback process where the estimated force from myoelectric potentials is continuously refined. The system compares the estimated muscle force with the actual applied force (when available from indirect measurements) and adjusts the musculoskeletal model parameters accordingly, progressively improving the accuracy of force estimation while maintaining non-invasive measurement.
Solution Approach 2:
The patent dynamically adjusts parameters of the musculoskeletal model based on measured myoelectric potentials and observed motion. By changing model parameters such as muscle activation levels, leverage arms, and joint moments in response to real-time measurements, the system improves the correlation between muscle tension and actual applied force, thereby enhancing measurement precision.
3Measurement precision
If multiple sensors are used to estimate force, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the myoelectric potential measurement system multi-functional by using the same sensor setup for multiple purposes: measuring muscle activation, estimating muscle force, and ultimately determining the force applied at the point of action. This universal approach allows a single sensor system to provide comprehensive force information without requiring separate specialized sensors for each function.
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
Enables accurate estimation of the force applied at a point of action without interfering with the work process, improving the assessment of work quality and efficiency by correlating posture, muscle activity, and applied forces.
Implementation Method 1
a myoelectric potential meter configured to measure a myoelectric potential from a surface of the body
Data Source
AI summary
An information processing apparatus includes: a preparation device preparing information on a body posture; an acting force meter measuring a first acting force the body applies on a first object; a myoelectric potential meter; and a processor acquiring the information on the posture, acquiring information on the first acting force measured by the acting force meter, acquiring information on the myoelectric potential, setting an initial value for a second acting force the body applies to a second object other than the first object, estimating a muscle activity state corresponding to the posture, the first acting force, and the second acting force, repeating updating the second acting force such that a difference between (i) a muscle activity state determined based on the myoelectric potential and (ii) the estimated activity state decreases, and presenting the second acting force when the difference is less than a predetermined threshold value.