Moving Body Detector Malfunction Diagnosis Using Single Oscillator
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Solution Overview
Problem
Conventional moving body detectors require multiple hardware components and timers to implement malfunction detection, leading to increased cost and size.
Innovation Solution
A moving body detector that uses a single oscillator to generate an oscillation signal, a transmitter to send continuous energy waves, a receiver to detect reflected waves, a phase-detector to calculate Doppler signals, and a controller to switch between moving body detection and malfunction detection modes, allowing for malfunction detection without additional hardware or timers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple oscillators and timers are used to implement malfunction detection, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the single oscillator and timer serve dual functions: they generate the oscillation signal for normal moving body detection and also generate the reference signal for malfunction detection. The controller switches between different operational modes (normal detection mode and malfunction detection mode) to utilize the same hardware resources for different purposes, thereby achieving malfunction detection capability without adding extra oscillators or timers.
Solution Approach 2:
The patent introduces dynamic switching of the oscillator's output signal destination based on operational mode. During normal operation, the oscillation signal is sent to the transmitter and phase detector for moving body detection. When malfunction detection is needed, the controller switches the signal routing to compare the oscillator output directly with the phase detector output, enabling malfunction detection without hardware changes.
2Reliability
If multiple timers are used for malfunction detection, then detection reliability is improved, but the device size increases
Solution Approach 1:
The single timer in the controller is made to serve both normal detection operations and malfunction detection operations. The timer generates timing signals that coordinate the oscillator operation and signal switching between different modes, eliminating the need for a separate dedicated timer for malfunction detection and thereby reducing the overall detector size.
Solution Approach 2:
The patent merges the malfunction detection function into the existing detection framework by combining the oscillator, timer, and signal processing paths. Instead of having separate hardware systems for normal detection and malfunction detection, the patent integrates both functions into a unified system where the same components perform both roles under different operational modes.
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 malfunction detection while maintaining a compact size and low cost, as it uses a single oscillation signal for both detection modes, ensuring secure detection of malfunctions without occupying multiple timers or increasing hardware complexity.
Implementation Method 1
transmits, to a space to be monitored, continuous energy waves, such as ultrasonic waves or radio waves
Implementation Method 2
receiving a reflected wave generated due to reflection of the ultrasonic waves by an object
Implementation Method 3
detects a frequency shift of a reflected wave generated due to movement of an object within the space to be monitored
Implementation Method 4
mixes the oscillation signal and the receiving signal to obtain a Doppler signal according to a frequency difference
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
In a malfunction detection mode, a controller is configured to compare an output of a phase-detector obtained when controlling to input an oscillation signal to only the phase-detector, with an output of the phase-detector obtained when controlling to input the oscillation signal to both of a transmitter and the phase-detector. If a change (difference) of signal levels of the outputs is equal to or more than a prescribed threshold, the controller determines that there is no malfunction in the transmitter and a receiver. If the change of the signal levels is less than the prescribed threshold, the controller determines that there is a malfunction in the transmitter or the receiver. Therefore, unlike a conventional moving body detector, it is possible to detect presence or absence of malfunction occurrence with only one kind of the oscillation signal, and accordingly achieve addition of a malfunction detection function, while suppressing increase in the cost or the size.