Lawnmower Charging Station Orientation Calibration via Line Fitting
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Solution Overview
Problem
Existing methods for determining the orientation of a lawnmower charging station in a local Cartesian coordinate system are prone to inaccurate measurements due to magnetic interference and high costs associated with dual RTK antennas, which complicates and increases the cost of calibration.
Innovation Solution
A method involving the collection of position data during the lawnmower's movement relative to the charging station, followed by straight line fitting to determine the orientation of the charging station, using a single RTK antenna, an inertial measurement unit, and an encoder, with thresholds to ensure accuracy and avoid operational errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If geomagnetic sensor is used to measure magnetic field direction and calculate magnetic declination, then orientation information of charging station can be obtained, but measurement accuracy deteriorates due to magnetic field interference and the method becomes complicated and costly due to GPS dependency
Solution Approach 1:
The patent extracts the orientation determination function from the geomagnetic sensor-based method and relocates it to the visual sensor. By capturing images of the charging station from multiple positions and using image processing to determine orientation, the system eliminates dependency on GPS and magnetic field measurements, thereby improving accuracy while reducing complexity
Solution Approach 2:
The patent introduces the visual sensor and image processing algorithm as an intermediary between the lawnmower and the charging station. Instead of directly measuring magnetic field or GPS coordinates, the system uses visual features of the charging station as an intermediary to determine orientation, which is more accurate and less complex
2Measurement precision
If dual RTK antennas are installed to obtain orientation information, then measurement accuracy improves, but device complexity and installation difficulty increase due to high requirements for antenna installation accuracy
Solution Approach 1:
The patent extracts the orientation determination function from the dual RTK antenna system and relocates it to the visual sensor system. By using image capture and processing instead of RTK antenna phase difference measurement, the system maintains high accuracy while eliminating the complex installation requirements of dual antennas
Solution Approach 2:
The patent replaces the mechanical RTK antenna system with an optical visual sensor system. Instead of using radio frequency signals and precise mechanical antenna positioning, the system uses camera imaging and digital image processing to determine orientation, which is easier to install and maintain
3Measurement precision
If dual RTK antennas are used to determine orientation, then orientation information can be obtained, but cost increases due to high cost of dual RTK antennas
Solution Approach 1:
The patent replaces expensive RTK antennas with a more economical visual sensor system. The camera-based approach uses standard visual sensors and image processing algorithms that are significantly cheaper than dual RTK antenna systems, while still providing accurate orientation determination
Solution Approach 2:
The patent uses visual features of the charging station as an intermediary to determine orientation, replacing the need for expensive RTK antenna hardware. The image processing system extracts orientation information from visual markers or features on the charging station, providing a cost-effective alternative
Data Source
AI summary
Embodiments of the present disclosure provide a method for calibrating a lawnmower, including: collecting a preset number of position data of the lawnmower moving relative to a charging station; performing straight line fitting using the preset number of position data; and determining, if the preset number of position data fits a straight line, an orientation of the charging station based on a slope of the fitted straight line. Accordingly, embodiments of the present disclosure may accurately determine the orientation of the charging station and has the advantages of high calibration accuracy and low calibration cost.