Autonomous Robot Navigation Using Periodic Signal Phase Detection
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Solution Overview
Problem
Existing autonomous mobile robots, such as lawn mowers, face challenges in accurately determining their position relative to a peripheral electric wire boundary due to variations in signal amplitude and noise interference, which affects their navigation and boundary detection.
Innovation Solution
A multichannel scaler or averager filter is used to measure the amplitude and phase of a periodic signal from the peripheral wire, allowing for constant signal-to-noise ratio and precise determination of the robot's position by sampling and storing signal data in independent memory, with numerical analysis by a microprocessor to interpret the data and determine distance from the wire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple amplitude measurement method is used, then the device complexity is reduced, but the measurement precision deteriorates due to signal variations and noise interference
Solution Approach 1:
The patent applies periodic action by using the periodic nature of the electromagnetic signal from the peripheral wire. The signal amplitude varies periodically as the robot moves, and this periodic variation is exploited to determine position and detect boundary crossings. The microprocessor analyzes the periodic signal pattern to identify when the robot crosses the boundary wire, enabling precise measurement without complex additional hardware.
2Adaptability or versatility
If the robot moves closer to or farther from the peripheral wire, then the signal amplitude varies, but this causes measurement precision to deteriorate due to non-constant signal-to-noise ratio
Solution Approach 1:
The patent implements feedback by continuously monitoring the electromagnetic signal amplitude and using this information to adjust position determination. The microprocessor receives feedback from the signal variations and uses algorithms to interpret these changes, determining whether the robot is approaching or receding from the boundary wire. This feedback mechanism maintains measurement precision across varying distances by dynamically adapting to signal strength changes.
3Productivity
If noise interference is present in the electromagnetic signal, then the signal-to-noise ratio decreases, but this causes measurement precision to deteriorate in position determination
Solution Approach 1:
The microprocessor uses feedback from the signal characteristics to distinguish between actual boundary crossings and noise interference. By analyzing the pattern, amplitude, and phase of signal variations over time, the system can filter out random noise and reliably detect true boundary events, maintaining accurate navigation even in noisy electromagnetic environments.
Solution Approach 2:
The patent introduces an intermediary processing layer (the microprocessor with signal analysis algorithms) that mediates between the raw electromagnetic signal and the position determination. This intermediary analyzes and interprets the signal, separating meaningful boundary crossing information from noise interference, thereby preserving measurement precision despite environmental electromagnetic disturbances.
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 solution enables accurate and consistent navigation by maintaining a constant signal-to-noise ratio and precise phase detection, allowing the robot to determine its position and stay within the defined boundary, even in the presence of noise, and also enables detection of phase changes and potential messages from the wire.
Implementation Method 1
a means for measuring the amplitude of a periodic electromagnetic signal of low frequency produced by one or several limiting elements
Implementation Method 2
which is a particular variant of a filter adapted to the detection of periodical signals... This type of device carries out several synchronic samplings of the signal amplitude during each period
Implementation Method 3
By passing through the interior of the loop on the exterior, the lines of force change direction and generate a signal phase change of 180° according to the general laws of electromagnetism
Data Source
AI summary
The invention concerns a navigation device for a mobile robot comprising means for measuring the amplitude and the phase of an electromagnetic signal emitted by a wire acting as limit for a working area of the robot. The measuring means samples the amplitude of the signal during each time interval, the result of each measurement is stored in a memory and the measurements are repeated for several time intervals, the collected results being added in said memories until the content of a memory reaches a reference threshold. The number of samples required and the content of each memory is interpreted by numerical analysis to determine the distance or distance variation relative to said limiting elements. Any phase change corresponding to a passage beyond the limiting wire is easily detected and results for example in a command returning the robot to its working area.