Automated Rotational Actuator for PPG Sensor Testing
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Solution Overview
Problem
Existing methods for testing photoplethysmogram (PPG) sensors are impractical and inaccurate due to the need for human subjects and inability to control physiological measurements precisely.
Innovation Solution
An automated rotational actuator system that simulates tissue reflectivity by actuating light reflecting surfaces towards and away from the PPG sensor, allowing for programmable simulation of heart rates and other physiological behaviors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If human subjects are used for testing PPG sensors, then physiological measurements can be obtained, but time consumption and personnel constraints increase significantly
Solution Approach 1:
The patent creates a artificial copy of human tissue using a variable reflectivity disc that simulates the optical properties and physiological behavior of actual tissue. This disc can be rotated to different positions to simulate various physiological conditions (different heart rates, blood volume changes) without requiring actual human subjects, thereby maintaining measurement accuracy while dramatically improving testing efficiency
Solution Approach 2:
The variable reflectivity disc acts as an intermediary between the testing system and the PPG sensor. Instead of directly testing on human subjects, the system uses this intermediary device that can be precisely controlled to simulate physiological conditions, enabling automated testing while maintaining the ability to assess sensor performance under realistic conditions
2Measurement precision
If human subjects are used for testing PPG sensors, then physiological data can be collected, but control over physiological measurements is imprecise
Solution Approach 1:
The system uses a dynamically controllable variable reflectivity disc that can be rotated to different positions to simulate varying physiological conditions. The disc's reflectivity can be changed dynamically through rotation, allowing precise control over the physiological parameters being tested (heart rate, blood volume changes) without relying on human subject variability or complex manual intervention
Solution Approach 2:
The patent changes the reflectivity parameter of the test object by rotating the disc to different positions. Each position corresponds to a specific reflectivity value that simulates different physiological states. This allows precise control over the physiological parameters being tested by simply changing the disc's rotational position, making the testing process both controllable and operationally simple
3Reliability
If large numbers of PDs are tested on humans, then quality assurance improves, but time and resource constraints are exceeded
Solution Approach 1:
By using an artificial tissue copy (variable reflectivity disc) instead of actual human subjects, the system enables rapid automated testing of multiple photodetectors. The disc can be quickly repositioned and reused indefinitely, allowing high-volume testing without the time constraints and ethical limitations of human subject testing, thereby ensuring quality assurance for large numbers of sensors
Solution Approach 2:
The system employs periodic rotation of the variable reflectivity disc to simulate rhythmic physiological conditions such as heartbeats. This periodic action allows automated, repeatable testing sequences that can be executed rapidly and consistently across multiple photodetectors, significantly reducing the time required for quality assurance while maintaining reliable assessment of sensor performance
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 efficient and accurate testing of PPG sensors by simulating various physiological conditions, ensuring quality and sensitivity of the sensors without the limitations of human testing.
Implementation Method 1
The rotational actuator may include one or more light reflecting surfaces that can be actuated towards and away from the PPG sensor to simulate reflectivity of the tissue of a subject
Implementation Method 2
A photo-detector (PD) may detect the reflected light, and as light varies through time, the blood volume changes in the tissue may be determined
Data Source
AI summary
Systems and methods of embodiments of the present disclosure provide automated testing of PPG sensors using a programmatically controlled rotational actuator. The rotational actuator may include one or more light reflecting surfaces that can be actuated towards and away from the PPG sensor to simulate reflectivity of the tissue of a subject. Particular heart rates, heart rate variabilities and/or other physiological behaviors may be simulated based on actuations patterns, including, e.g., frequency, range of actuation, or variations thereof, among other actuation pattern characteristics. Based on the output signal produced by the PPG sensor in response to the actuation pattern, the PPG sensor may be assessed for accuracy and/or sensitivity to ensure quality.