Boundary Wire Signal Coding for Interference-Resistant Robotic Mowers
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Solution Overview
Problem
Existing systems for controlling self-propelling lawnmowers within boundary wires are complex, expensive, and sensitive to interference, requiring complex electronics and synchronization for signal reception.
Innovation Solution
A method and system using a DC-balanced alternating current data frame with a recognition code, comprising a system code and loop number code, randomly transmitted as bursts, allowing the lawnmower to determine its position within the boundary wire without synchronization, enhanced by a cryptographic True Random Number Generator for increased robustness against interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed phasing is used to determine lawnmower position, then the determination method is simple, but the electronics in the control unit become complex and expensive
Solution Approach 1:
The patent changes the parameter of signal transmission from fixed phasing to random transmission within a time window. This allows the use of correlation methods that are more robust to interference while maintaining position determination accuracy, thereby reducing the complexity requirements for control unit electronics.
Solution Approach 2:
The patent employs periodic transmission of data frames at random intervals within a defined time window. This periodic yet randomized approach enables the receiving end to use correlation-based detection that is less sensitive to interference, simplifying the control unit electronics while maintaining measurement precision.
2Reliability
If fixed phasing is used for signal transmission, then the system is simple to implement, but it becomes very sensitive to interference
Solution Approach 1:
The patent introduces dynamic randomization in the transmission timing of data frames. Instead of fixed phasing, the signal is transmitted at random moments within a time window, making the system adaptive to interference conditions and enabling the use of correlation methods that enhance reliability without excessive complexity.
Solution Approach 2:
The patent performs preliminary encoding of data frames with recognition codes before random transmission. This preliminary action allows the receiving end to correlate expected patterns with received signals, enhancing interference resistance while keeping the overall system complexity manageable.
3Reliability
If convolution method is used to compare signals, then electromagnetic resistance is improved, but the method becomes more complex
Solution Approach 1:
The patent extracts the essential feature for interference resistance by using correlation of predetermined patterns rather than full convolution. This extraction approach maintains electromagnetic resistance while reducing computational complexity by focusing only on the critical comparison elements.
Solution Approach 2:
The patent uses simple predetermined patterns that can be easily generated and compared, replacing complex convolution operations. These simple pattern comparisons achieve sufficient electromagnetic resistance with much lower computational cost and simpler implementation.
4Productivity
If burst transmission is used, then data transmission is efficient, but synchronization is required for signal reception
Solution Approach 1:
The patent enables the receiving end to autonomously detect and process burst signals without external synchronization by using correlation with predetermined patterns. The system self-adjusts to the random transmission timing, eliminating the need for complex synchronization mechanisms while maintaining transmission efficiency.
Solution Approach 2:
The patent employs correlation-based detection that provides implicit feedback about signal presence and quality. This feedback mechanism allows the receiving end to adapt to random burst timing without synchronization, maintaining productivity while reducing device complexity.
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
The solution provides a robust and interference-resistant system for controlling self-propelling lawnmowers, reducing complexity and cost by eliminating the need for synchronization and enhancing resistance to electromagnetic interference.
Implementation Method 1
Two signals with alternating voltage are applied simultaneously by a signal generator to the border delimitation wire. The two signals create alternating electromagnetic fields, which are detected by receiving coils in the lawnmower.
Implementation Method 2
The received signals are evaluated in order to decide if the lawnmower is located within or outside the border delimitation wire.
Data Source
AI summary
A method and a system for controlling a self-propelling lawnmower including the self-propelling lawnmower having a control unit and at least one sensor, a boundary wire and a signal generator. The self-propelling lawnmower moves across an area surrounded by the boundary wire. By encoding a data frame with a recognition code in an alternating current that is Direct Current, DC-balanced and that is randomly transmitted within a predetermined period of time, by means of the signal generator, to the boundary wire a system robust against interference is accomplished. The data frame burst is received by a sensor and decoded by a control unit in the lawnmower. By comparing the received recognition code with a stored recognition code, the control unit determines that the lawnmower is on the inside of the boundary wire if the received recognition code matches the stored recognition code, and on the outside if the received recognition code matches the inverse of the stored recognition code.