Surface type detection
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Solution Overview
Problem
Devices that operate on or move across surfaces face challenges in accurately detecting surface types, such as distinguishing between hard and soft surfaces, due to interference from ringdown signals, which can obscure returned sonic signals.
Innovation Solution
The implementation of a surface type detection system that estimates a 'void ringdown signal' by sampling early ringdown points and extrapolating, allowing for the comparison of actual ringdown signals with the estimated void signal to generate metrics for determining surface types, using techniques like background subtraction and curve length analysis in the complex domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sonic signals are transmitted to detect surface types, then surface detection capability is enabled, but ringdown signals obscure the returned sonic signals and reduce measurement precision
Solution Approach 1:
The patent extracts and removes the ringdown signal component from the received signal by modeling it as an exponential decay function and subtracting it from the total signal. This isolation and removal of the harmful ringdown component allows the returned sonic signal to be clearly detected without interference, directly resolving the measurement precision issue caused by ringdown interference.
Solution Approach 2:
The patent introduces an intermediary mathematical model (exponential decay function) to represent and separate the ringdown signal from the returned signal. This intermediary modeling approach acts as a mediator that enables the distinction between the two overlapping signals, allowing accurate extraction of the returned signal characteristics for surface type detection.
2Adaptability or versatility
If the device operates on multiple surface types, then adaptability is improved, but the complexity of detecting and measuring surface types increases
Solution Approach 1:
The patent changes the parameter representation of surface types by analyzing the characteristics of the returned signal after ringdown removal. By examining parameters such as signal amplitude, decay rate, and time-of-flight of the returned sonic signal, the system can distinguish between different surface types (hard, soft, carpet) through measurable physical parameters rather than complex qualitative assessment.
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 enables effective discrimination of surface types, improving the accuracy of surface detection and enabling devices to adjust operations accordingly, such as changing cleaning modes based on surface hardness or cleanliness.
Implementation Method 1
a sonic transducer configured to transmit sonic signals toward a surface and receive returned signals from the surface
Implementation Method 2
the type of the surface may be obscured by a ringdown signal generated by the sonic transducer
Data Source
AI summary
A robotic cleaning appliance includes a sonic transducer and a processor coupled with a housing. The sonic transducer transmits sonic signals toward a surface within its ringdown distance and receives corresponding returned signals. Following cessation of the sonic signals, the processor samples the ringdown signal generated by the sonic transducer during an early portion before the corresponding returned signals have reflected back to the sonic transducer, and during a later portion which includes the corresponding returned signals. The processor utilizes the sampled early portion to estimate a void ringdown signal of which represents performance of the sonic transducer in absence of returned signals being received. The processor compares the estimated void ringdown signal to the later portion of the ringdown signal and generates a metric based on the comparison. The processor utilizes the metric to determine a type of the surface, out of a plurality of surface types.