Ultrasonic Transducer Coexistence via Randomized Sensing Cycles
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Solution Overview
Problem
In environments where multiple ultrasonic sensors operate simultaneously, there is a challenge with false detections of moving objects due to interference from neighboring devices, leading to unnecessary actions or evasive maneuvers.
Innovation Solution
Implementing randomized sensing cycles for ultrasonic sensors, which maintain the same overall measurement frequency as fixed cycles but randomize the timing of transmit and receive periods, reducing interference and false detections by disrupting patterns associated with overlapping signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple ultrasonic sensors operate simultaneously in the same environment, then the sensing coverage and functionality are improved, but false detections of moving objects occur due to interference from neighboring devices
Solution Approach 1:
The patent implements randomized sensing cycles where each ultrasonic sensor operates in periodic transmit and receive modes, but the timing of these cycles is randomized rather than fixed. This periodic action with random timing allows multiple sensors to coexist by preventing consistent interference patterns, thereby maintaining sensing coverage while reducing false detections caused by neighboring ultrasonic devices.
2Measurement precision
If fixed sensing cycles are used for ultrasonic sensors, then the measurement frequency is consistent, but interference patterns occur when multiple sensors operate in the same environment
Solution Approach 1:
The patent transitions from static fixed sensing cycles to dynamic randomized sensing cycles. Each sensor maintains a consistent average measurement frequency, but the actual timing of transmit and receive periods varies randomly. This dynamic approach allows the system to adapt timing conditions to avoid interference patterns while preserving measurement frequency consistency over time.
Solution Approach 2:
The patent changes the timing parameters of the sensing cycles from fixed values to randomized values. By varying the start times and durations of transmit and receive periods while maintaining the same average frequency, the system alters the temporal parameters to avoid constructive interference patterns that occur with synchronized fixed cycles, thereby reducing harmful interference effects.
3Ease of operation
If ultrasonic sensors use fixed transmit and receive timing, then the operation is simple and predictable, but false positive detections occur due to overlapping signals from other devices
Solution Approach 1:
The patent implements preliminary randomization of the sensing cycle timing before operation begins. Each sensor pre-determines its randomized transmit and receive window timings, which simplifies the operational control while preventing false positives. This preliminary action establishes non-overlapping operational patterns that maintain simplicity while eliminating the need for complex real-time collision avoidance logic.
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 false positive detections of moving objects, allowing multiple ultrasonic sensors to coexist in the same environment without interference, with devices experiencing extended periods without false object detection.
Implementation Method 1
a sensor processing unit (SPU) 120 of the device 100 controls the ultrasonic transducer 150 to repeatedly emit ultrasonic pulses during transmit periods of a plurality of sensing cycles
Data Source
AI summary
A device comprises a processor coupled with an ultrasonic transducer which is configured to repeatedly emit ultrasonic pulses during transmit periods which are interspersed with listening windows. Each sequential pair of the transmit periods is separated by a single listening window of the listening windows. During a fixed portion of a listening window of the listening windows the ultrasonic transducer is configured to receive returned signals corresponding to an emitted ultrasonic pulse of the ultrasonic pulses which was transmitted during a transmit period of the transmit periods that immediately preceded the listening window. The processor randomizes an overall length of each listening window of the listening windows. The processor directs filtering of returned signals received during a plurality of the randomized listening windows to achieve filtered returned signals. The processor detects, using the filtered returned signals, a moving object in a field of view of the ultrasonic transducer.