Rear Seat Passenger Detection Using SBR Sensor Output
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Solution Overview
Problem
Current vehicle systems struggle to detect passengers on rear seats, especially when movements are minute, and rely on costly ultrasonic sensors, which also measure load using seat belt reminder (SBR) sensors, leading to increased production costs and inaccurate passenger detection.
Innovation Solution
A vehicle system equipped with belt buckle sensors and SBR sensors on each rear seat, a controller determines the presence of a passenger or object based on SBR sensor output, and outputs a warning message via an output device when the vehicle is turned off and the seat belt is worn or not worn, ensuring passenger safety by preventing unattended infants or adults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic sensors are used to detect passenger movement on rear seats, then detection capability is improved, but production cost increases
Solution Approach 1:
The SBR sensor is designed to serve multiple functions: it detects both the presence of passengers and their weight load, and now also detects minute movements by monitoring changes in its output value. This eliminates the need for separate ultrasonic sensors, reducing production costs while maintaining detection capability.
Solution Approach 2:
The system detects passenger movement by monitoring changes in the output value of the SBR sensor rather than using a separate movement detection mechanism. By analyzing temporal variations in the sensor's output signal, the system can detect minute movements without requiring additional hardware.
2Ease of manufacture
If SBR sensor is used to measure load and detect passengers, then production cost is reduced, but detection accuracy for minute movements deteriorates
Solution Approach 1:
The system continuously monitors the output value of the SBR sensor and compares it against reference values to detect changes indicating passenger movement. By implementing a feedback mechanism that analyzes temporal variations in the sensor signal, the system achieves accurate movement detection using the existing SBR sensor infrastructure.
Solution Approach 2:
The controller stores reference output values from the SBR sensor when no passenger is present, establishing a baseline for comparison. This preliminary action enables the system to accurately detect deviations caused by passenger presence and movement without requiring additional sensors.
3Reliability
If the system warns only when vehicle is on, then warning coverage is reduced, but system complexity is lowered
Solution Approach 1:
The system performs passenger detection and issues warnings even when the vehicle is turned off, by monitoring SBR sensor output values and door sensor states. This preliminary action ensures that passengers, especially children, are not left unattended in the vehicle, expanding safety coverage without requiring complex additional hardware.
Data Source
AI summary
The vehicle system includes an output device, a plurality of rear seats, a plurality of belt buckle sensors provided on each of the plurality of rear seats, a plurality of seat belt reminder (SBR) sensors provided on each of the plurality of rear seats, and a controller. The controller is configured to determine one rear seat on which a passenger or an object having a weight equal to or less than a predetermined weight is located based on an output value of the SBR sensor, determine whether a seat belt corresponding to the determined rear seat is worn based on an output value of the belt buckle sensor, and control the output device to output a warning message when the vehicle is turned off and a door of the rear seat is not opened or closed in a state in which the seat belt is worn.