Opposite Pressure Sensors for Fall Detection Error Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fall detection systems using pressure sensors face inaccuracies due to orientation variations, leading to false dismissals or alarms, as the weight of the sensor and its protective gel affect the deformation of the pressure sensing element, resulting in altitude value errors exceeding 50 cm.
Innovation Solution
The use of two pressure sensors with opposite orientations, either through opposite normal directions of their pressure sensing surfaces or by configuring them in a housing where the sensing surface is vertical to the gravity direction, allows for the compensation of orientation-induced errors by deriving a third data value from the first and second data values obtained by the sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is used to measure altitude change for fall detection, then the fall detection function can be implemented, but measurement precision deteriorates due to orientation variations causing errors exceeding 50 cm
Solution Approach 1:
The patent divides the single pressure sensor into two separate pressure sensors with opposite orientations. Each sensor measures pressure from a different directional perspective, allowing the system to segment the measurement task and compensate for orientation-induced errors by comparing or averaging the readings from both sensors.
Solution Approach 2:
The patent applies the anti-weight principle by configuring two pressure sensors with opposite normal directions. The weight effect on one sensor is counterbalanced by the opposing sensor, as the gravitational force acts in opposite directions relative to each sensor's sensing element, thereby eliminating the net orientation error.
2Measurement precision
If the pressure sensor's orientation is fixed to eliminate measurement errors, then measurement precision improves, but device complexity increases due to additional sensors and processing
Solution Approach 1:
Instead of making the entire system complex with active orientation control mechanisms, the patent segments the sensing function into two simple, fixed-oriented sensors. Each sensor maintains a simple fixed configuration, and the complexity is distributed rather than centralized, making the overall system more manageable.
Solution Approach 2:
The patent changes the parameter of sensor orientation from a single variable requiring active control to two fixed parameters that are oppositely configured. This parameter transformation simplifies the control system while maintaining measurement precision through the mathematical relationship between the two sensors' readings.
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 significantly reduces or eliminates measurement errors caused by pressure sensor orientation variations, enhancing the accuracy of fall detection by ensuring precise altitude value measurements with a resolution of about 10 cm.
Implementation Method 1
the atmosphere pressure is measured by detecting the deformation, in response to the atmosphere pressure, of a pressure sensing element comprised in the pressure sensor
Implementation Method 2
the weight of the pressure sensing element affects the deformation of the pressure sensing element when the pressure sensor's orientation varies
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 2c~2e
AI summary
This invention relates to methods and apparatus for detecting a fall of a user,especially to methods and apparatus for detecting a fall of a user by using pressure sensors. This invention discloses an apparatus for detecting a fall of a user, and the apparatus comprises first and second pressure sensors configured to obtain first and second data values of atmosphere pressure and intended to be worn on the body of the user, and a processor configured to derive a third data value of atmosphere pressure for determining whether a fall occurs or not from the first and second data values of atmosphere pressure. The first and second pressure sensors are configured in a way such that preset orientations of the first and second pressure sensors are opposite to each other. In this way, the weight of measuring elements comprised in the first and second pressure sensors have opposite effects on the measured atmosphere pressure, and thus(?) the measurement error caused by pressure sensor orientation variation can be reduced or even eliminated.