Capacitance Probe Design for Accurate Robotic Lawn Detection
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Solution Overview
Problem
Traditional intelligent mowers face issues with poor sensitivity of capacitance sensors due to end covers that hinder electric field transmission, and rubbing against grasslands increases walking resistance, affecting detection accuracy and efficiency.
Innovation Solution
A self-moving device equipped with capacitance sensors featuring a metal polar plate and a conductive end cover for enhanced sensitivity, along with an adjustable probe to minimize contact with the ground, allowing for improved detection and reduced walking resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional end cover is used to protect the probe, then the probe is protected from damage, but the electric field transmission is hindered causing poor sensitivity
Solution Approach 1:
A conductive layer is introduced as an intermediary between the probe and the ground. This conductive layer has high electrical conductivity that facilitates electric field transmission while still providing protective coverage for the probe, thus resolving the contradiction between protection and sensitivity
Solution Approach 2:
The end cover is transformed from a traditional insulating material to a conductive material with specific electrical conductivity parameters. By changing the material parameter (from insulating to conductive), the end cover now enhances electric field transmission while maintaining its protective function
2Device complexity
If the capacitance sensor adopts a fixed columnar type, then the structure is simple, but the sensor easily rubs against the grassland increasing walking resistance
Solution Approach 1:
The fixed columnar sensor is replaced with an adjustable sensor mechanism that can dynamically change its height position. This allows the sensor to be raised when not in use to avoid contact with grassland, reducing walking resistance, and lowered when detection is needed
Solution Approach 2:
The sensor is extracted from its fixed position and made independently adjustable. This separation allows the sensor to be positioned independently from the main body, enabling it to avoid ground contact during movement while remaining accessible for detection operations
3Measurement precision
If the probe area is increased to improve detection accuracy, then the sensitivity improves, but the contact with ground increases causing more rubbing resistance
Solution Approach 1:
A conductive film or thin conductive layer is used instead of a bulky probe structure. This thin film provides sufficient detection area for accuracy while being thin enough to minimize ground contact and rubbing resistance when the sensor is in its lowered position
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 enhances the sensitivity and accuracy of grassland detection, reducing misjudgments and increasing the efficiency of lawn trimming by minimizing sensor contact with the ground, thus improving the overall performance of the automatic mower.
Implementation Method 1
The capacitance sensor detects the ground below the mower, judges whether the ground is the grassland to be mowed
Implementation Method 2
the end cover on the bottom of the capacitance sensor is unfavorable for transmission of an electric field of the probe
Data Source
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Figure 3(a)
AI summary
The present invention relates to a self-moving device, which moves and works in a working area defined by a limit and comprises a shell, a moving module, a task executing module and a control module; the control module controls the moving module to drive the self-moving device to move and controls the task executing module to execute a work task; the self-moving device comprising at least one capacitance sensor, which is mounted in the shell and electrically connected to the control module and detects whether a surface below the self-moving device or in front of a moving direction is a surface to be machined; the capacitance sensor comprises at least one probe, the probe comprises a probing surface located on the outer surface of the probe, and a conductivity of at least part of the probing surface is larger than or equal to 10-9s/m; or a distance between the probe and the surface below the self-moving device meets a first preset condition; or an area of the probing surface meets a second preset condition.