Robotic Mower Guide-Wire Following With Randomized Offset Control
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Solution Overview
Problem
Robotic mowers form tracks in lawns due to repetitive path following, especially when using guide or boundary wires, which is exacerbated by varying signal levels and environmental conditions.
Innovation Solution
The robotic mower uses odometry to adjust a random distance from the wire, measuring signal levels to maintain this distance, and employs sensor polarity changes to determine direction, reducing the need for signal level ranges and enhancing path randomness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robotic mower follows the guide wire at a fixed distance, then navigation efficiency is improved, but track formation occurs due to repetitive paths
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed distance to a random distance value. The control unit selects a random distance from a range, making the mower's path dynamic and unpredictable. This resolves the contradiction by maintaining navigation efficiency (still following the guide wire) while eliminating track formation (through randomized positioning).
Solution Approach 2:
The patent changes the parameter of distance from a constant value to a random variable. By selecting distance randomly from a predefined range, the system maintains the functional relationship with the guide wire while introducing variability that prevents repetitive track formation.
2Ease of operation
If signal level ranges are used for controlling distance, then control simplicity is improved, but path randomness is reduced leading to track formation
Solution Approach 1:
The patent extracts the signal level dependency from the distance control mechanism. Instead of using signal level to determine distance (which creates predictable patterns), the system uses signal level only for detection and alignment, while distance is independently selected randomly. This separates the control functions and eliminates track formation.
Solution Approach 2:
The patent applies preliminary action by pre-defining a range of valid distances before operation. The control unit randomly selects from this predefined range, ensuring both simplicity (predefined bounds) and randomness (unpredictable selection within bounds), thereby preventing track formation while maintaining ease of control.
3Adaptability or versatility
If the mower adjusts to varying signal levels, then adaptability to different environments is improved, but distance consistency deteriorates causing unstable path following
Solution Approach 1:
The patent segments the navigation function into two independent parts: (1) signal level detection for environmental adaptation and alignment, and (2) random distance selection for precise path control. This segmentation allows the system to adapt to varying signal levels without affecting distance consistency, as the random distance is selected independently of signal strength variations.
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 method significantly reduces the formation of tracks by ensuring precise and unpredictable path variations, even with varying signal levels and environments, maintaining efficient navigation to charging stations.
Implementation Method 1
detecting, by means of at least one sensor, a signal from the wire
Data Source
AI summary
A method navigates a robotic mower by means of a wire. The robotic mower comprises at least one sensor. The method comprises detecting, by means of the at least one sensor, at least one signal from the wire, controlling the robotic mower to align with the wire, controlling the robotic mower to turn by an angle with respect to a section of the wire, controlling the robotic mower to increase the distance between the robotic mower and the wire by driving a displacement distance based on a random distance value, measuring, by means of the at least one sensor, a signal level of the at least one signal from the wire, and controlling the robotic mower to follow the wire based on the measured signal level.