Rain Sensor Electrode Polarization Mitigation
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Solution Overview
Problem
Existing rain sensors for autonomous working apparatuses, such as robotic mowers, face issues with inaccurate signal measurement due to polarization effects and electrochemical corrosion, especially when exposed to rain and sheltered environments.
Innovation Solution
The proposed autonomous working system incorporates a rain sensor with a base, electrodes, and a protrusion body, where the electrodes are embedded in the base and protrude through both ends, and the protrusion body is configured to be partially above the water collection surface with a gap, reducing direct rain impact and enhancing sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rain sensor is arranged on the robotic mower, then the robot can detect rain during working process, but when the robot stops at a docking station with shelter or canopy, the rain sensor is covered and cannot continue to receive rainwater, causing inaccurate judgment of when rain stops
Solution Approach 1:
The rain sensor is extracted from the robotic mower and placed on the docking station instead. This allows the sensor to remain in a fixed position where it can continuously detect rain conditions without being covered by the shelter or canopy, solving the problem of inaccurate rain stop detection while maintaining the robot's ability to respond to rain conditions.
2Measurement precision
If the rain sensor continuously receives rainwater to maintain detection accuracy, then the sensor can accurately judge rain conditions, but this causes polarization effects and electrochemical corrosion on the electrodes
Solution Approach 1:
The patent implements periodic polarity switching of the electrodes through a switching circuit. The electrodes alternate between positive and negative polarity at regular intervals, which prevents continuous polarization effects and reduces electrochemical corrosion. This periodic action maintains measurement precision while extending sensor durability by eliminating the harmful effects of continuous rainwater exposure on stationary electrodes.
3Measurement precision
If the electrodes are fully exposed to collect maximum rainwater, then the sensor can detect rain conditions, but this increases polarization effects and electrochemical corrosion
Solution Approach 1:
The patent designs the electrode structure with selective exposure - the electrodes are positioned to collect sufficient rainwater for detection while being partially protected by the sensor housing structure. The local geometry is optimized so that only the necessary portion of the electrodes is exposed to rainwater, reducing the total surface area subject to polarization and corrosion while maintaining adequate detection sensitivity.
Solution Approach 2:
The periodic polarity switching causes the electric field to alternate direction, which prevents the formation of stable polarization layers on the electrode surfaces. This continuous reversal of polarity disrupts the electrochemical reactions that would otherwise occur during continuous rainwater exposure, thereby reducing corrosion while maintaining detection functionality.
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 design improves the accuracy of rain detection by minimizing polarization effects and electrochemical corrosion, allowing the autonomous working apparatus to reliably stop or continue operations based on precise rain sensor data.
Implementation Method 1
a rain sensor with a base, electrodes, and a protrusion body, where the electrodes are embedded in the base and protrude through both ends
Implementation Method 2
improves the accuracy of rain detection by minimizing polarization effects and electrochemical corrosion
Data Source
AI summary
A rain sensor includes a base, where the base has an upper end face and a lower end face, which are opposite to each other. The rain sensor also includes a first electrode and a second electrodes disposed in the base and a protrusion body. The first electrode has an upper end that is exposed at least partially out of the upper end face of the base. The second electrode has an upper end that is exposed at least partially out of the upper end of the base. The protrusion body is at least partially disposed directly above the upper end face.