Farm Machine Angle Sensor Calibration Using GNSS Kinematics
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Solution Overview
Problem
The operation precision and land utilization rate of large-scale farm machines are compromised due to installation and manufacturing errors in the kinematic model of GNSS navigation automatic drive control systems, leading to inaccurate control and potential divergence in tractor operations.
Innovation Solution
An automatic calibration method for the angle sensor involves fixing the steering wheel, collecting and processing position information, establishing a two-wheel kinematics model, performing radius calculations, and fitting angle values to obtain calibration coefficients, allowing for precise calibration without external assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If installation and manufacturing errors are present in the kinematic model, then the automatic drive control system can be implemented, but the control accuracy deteriorates and the system may diverge
Solution Approach 1:
The patent applies preliminary action by performing angle sensor calibration before automatic drive control operations. The calibration process pre-compensates for installation and manufacturing errors in the kinematic model by establishing accurate correspondence relationships between angle sensor readings and actual wheel angles. This preliminary calibration ensures that subsequent control operations start with accurate baseline data, preventing control divergence and improving accuracy without requiring perfect manufacturing precision.
2Measurement precision
If traditional calibration methods are used, then the calibration process can be completed, but external assisting apparatus and manual operations are required, increasing complexity
Solution Approach 1:
The patent implements self-service by enabling the angle sensor calibration to be performed automatically using the farm machine's own GNSS receiver and existing sensor systems. The method utilizes the machine's built-in capabilities to collect position data, calculate actual wheel angles through kinematic models, and generate calibration coefficients without requiring external measurement equipment or manual intervention. This self-calibrating approach maintains high measurement precision while eliminating the complexity of external assisting apparatus.
Data Source
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AI summary
An automatic calibration method of an angle sensor for an automatic drive control system of a farm machine includes the following steps. Step S1: Step S1: fixing a steering wheel of the farm machine to make front wheels of a vehicle kept at a fixed angle. Step S2: collecting a plurality of pieces of current position information of the farm machine, and processing the plurality of pieces of current position information to obtain an average value. Step S3: establishing a two-wheel farm machine kinematics model based on a center of a rear axle. Step S4: performing a radius calculation to obtain a set of angle correspondences. Step S5: rotating the farm machine by a preset angle at a constant speed with the rear axle of the farm machine as a center, and performing Step S1 through Step S4;Step S6: after performing Step S5 for several times, performing an angle value fitting calculation to obtain a calibration coefficient. By applying the technique combining vehicle kinematics and high-precision GNSS, a high-precision angle sensor calibration can be realized without the external assisting apparatus and related experiential parameter input, and an automatic calibration can be realized. The present application is suitable for the precise agricultural automatic drive control systems.