Optical Force Sensor for Motor Skill Evaluation
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Solution Overview
Problem
Existing devices for evaluating upper limb motor capacity, particularly for individuals with neuromuscular disorders, suffer from low detection sensitivity and unreliable contact between keys and sensors, leading to distorted measurements due to friction and movement-induced errors.
Innovation Solution
A device with adjustable force sensors having a minimum detection threshold of 10g, integrated sensitivity threshold adjustment, and a low-density polyethylene foam support for improved precision and reliability, along with wireless data transmission and integrated display for adaptable measurement settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If keys rest by gravity on sensors, then the device structure is simple, but the contact is unreliable and sensitive to vibrations and shocks
Solution Approach 1:
The patent replaces the mechanical contact system (keys resting by gravity on sensors) with an optical detection system. The optical sensor detects the position and movement of keys through optical fields rather than physical contact, eliminating friction, wear, and vibration sensitivity while maintaining structural simplicity.
2Device complexity
If keys are in direct contact with sensors, then the detection mechanism is simple, but friction induces wear and distorts measurement thresholds
Solution Approach 1:
The patent eliminates mechanical contact between keys and sensors by using optical detection. This substitution removes friction and wear completely, ensuring that detection thresholds remain accurate and stable over time without being distorted by mechanical degradation.
Solution Approach 2:
The patent introduces an optical field as an intermediary between the keys and the detection system. This intermediary allows the system to detect key position and movement without physical contact, preventing friction-induced wear and threshold distortion while maintaining a simple detection mechanism.
3Ease of manufacture
If the detection threshold is fixed, then the device is simple to manufacture, but it cannot detect very weak pressures from individuals with neuromuscular disorders
Solution Approach 1:
The patent makes the detection threshold adjustable rather than fixed, allowing the system to adapt to different user needs. Individuals with neuromuscular disorders can have the threshold lowered to detect very weak pressures, while healthy users can have it set higher. This dynamic adjustment is implemented through programmable controls that do not significantly complicate manufacturing.
4Device complexity
If the device uses fixed-size keys, then the device structure is simple, but it cannot accommodate different sizes of hands and limbs
Solution Approach 1:
The patent implements adjustable key positions and potentially variable key sizes that can be configured to match different users' anatomical dimensions. This dynamic adaptability allows the device to accommodate various hand and limb sizes without requiring multiple fixed-size components, maintaining structural simplicity while enhancing versatility.
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
Enhances measurement accuracy and reliability by detecting weak pressures and reducing sensitivity to vibrations, allowing for precise evaluation of motor capacity with adjustable sensitivity and adaptable device size and shape.
Implementation Method 1
each being coupled to a force sensor able to generate a signal correlated to the force of the individual who presses on the button
Data Source
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AI summary
The invention relates to a device for evaluating the distal motor skills of the upper limbs of a person, which includes a main bearing surface (1) for all or part of an upper limb, a measurement means including two push members (2, 3), each of which is provided with a bearing surface (20, 30) lying in a plane parallel to and different from that of said main surface (1), and each of which is coupled to a force sensor capable of generating a signal relating to the force exerted by the individual on said bearing surface, and a control system coupled to the measurement means, said control system making it possible to count a number of alternating pushes on each bearing surface. According to the invention, the push members (or keys) (2, 3) are screwed onto the force sensor, and each force sensor has a precision of around 0.01%.