Air-Conditioning Control Using R-R Interval Thermal Sensation Estimation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing air-conditioning control systems face challenges in accurately determining a person's thermal sensation using a single sensor, as they often require multiple sensors, leading to discomfort and inaccurate readings due to the activation of sympathetic nerves.
Innovation Solution
An air-conditioning control system that uses a single measurer to derive multiple parameters, such as the ratio of low frequency to high frequency components in heart rate variations and respiration rates, to estimate thermal sensation and control air-conditioning capacity, providing a comfortable environment without constant sensor attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are attached to the body to measure thermal sensation parameters, then measurement precision is improved, but device complexity and user comfort deteriorate
Solution Approach 1:
The patent combines multiple measurement functions (autonomic nerve activity detection via R-R interval analysis and thermal sensation detection via body temperature/perspiration measurement) into a single integrated sensor system. This merging allows the system to derive both the LF/HF ratio for autonomic nervous system state and thermal sensation parameters from one sensor, eliminating the need for multiple separate sensors and reducing user burden while maintaining comprehensive measurement capability
Solution Approach 2:
The single sensor system is designed to perform multiple functions: it detects R-R intervals for autonomic nerve activity analysis, measures body temperature for thermal sensation assessment, and monitors perspiration levels. This multi-functional approach allows one sensor to replace what would traditionally require multiple specialized sensors, improving ease of use while maintaining measurement precision across different physiological parameters
2Loss of information
If multiple sensors are attached to the body, then thermal sensation can be understood, but sympathetic nerve becomes more active causing discomfort
Solution Approach 1:
The patent merges thermal sensation measurement and autonomic nerve activity monitoring into a single sensor system. By doing so, it minimizes the physical burden on users (reducing discomfort) while still capturing both the thermal sensation data and the sympathetic/parasympathetic nerve balance information needed to understand overall thermal comfort state
Solution Approach 2:
The system uses R-R interval variations as an intermediary parameter to indirectly assess autonomic nervous system state without requiring direct invasive measurement. This intermediary approach allows the system to gather comprehensive physiological information while maintaining non-invasive, comfortable monitoring conditions for the user
3Device complexity
If a single sensor is used to measure body movement, then device complexity is reduced, but measurement precision of multiple parameters deteriorates
Solution Approach 1:
The patent segments the analysis of a single sensor's output data into multiple distinct parameter sets. By applying different analytical methods to the same raw data (R-R interval segmentation into LF and HF components, separate analysis for body temperature and perspiration), the system derives multiple physiological parameters from one sensor, effectively achieving multi-parameter measurement capability without requiring multiple physical sensors
Solution Approach 2:
The system transforms a single sensor's measurements into multiple physiological parameters through mathematical transformations and signal processing. The R-R interval data is transformed into LF/HF ratio for autonomic nerve assessment, while other derived parameters provide thermal sensation information. This parameter transformation approach allows one sensor to provide comprehensive multi-parameter monitoring
Data Source
AI summary
This system correctly obtains a thermal sensation of a person in a room to provide a comfortable environment. A first parameter deriver derives, as a first parameter, a ratio of a low frequency component to a high frequency component in a variation of R-R intervals of a person, based on his/her body movement. A second parameter deriver derives, as a second parameter, any one of a coefficient of variation of R-R intervals, a respiration rate, or a heart rate of the person, based on the body movement of the person. An estimator estimates a thermal sensation of the person, based on the first parameter and the second parameter. A CPU for air-conditioning control controls an air-conditioning capacity of the air conditioner, based on a result of the estimation by the estimator.