GNSS Sidehill Compensation for Farm Implement Guidance
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Solution Overview
Problem
Existing farm guidance systems using GNSS positioning struggle with sidehill roll errors, yaw errors, and implement sidehill drift, leading to tracking errors when navigating uneven terrain, which affects the dynamics of automatic tractor steering and path accuracy.
Innovation Solution
A farm guidance apparatus and method that employs a compensation computer and sidehill compensator to calculate a sidehill tracking compensation based on GNSS position measurements, roll angle, and desired implement path, using a variable sidehill tracking function to minimize crosstrack errors, thereby compensating for roll, yaw, and implement sidehill drift errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the GNSS antenna is mounted high on the tractor to have a clear line-of-sight to satellites, then the antenna's two-dimensional horizontal position is displaced to the side of the implement ground point when the tractor is on a sidehill, causing roll error
Solution Approach 1:
The patent introduces an intermediary computational process that measures the roll angle of the tractor and uses trigonometric calculations to determine the lateral displacement of the antenna from the implement ground point. This intermediary calculation acts as a mediator between the high antenna mounting (which provides satellite visibility) and the accurate position determination (which requires knowing the antenna's lateral offset). By computing the roll angle and using it to calculate the lateral displacement, the system reconciles the conflict between mounting the antenna high for satellite visibility and maintaining position accuracy.
2Stability of the object's composition
If existing farm guidance systems use a fixed GNSS antenna height for compensation calculations, then the steering system causes the tractor path to be slow to respond or to have large side-to-side oscillating errors when the actual antenna height differs from the used height
Solution Approach 1:
The patent applies the dynamics principle by making the antenna height parameter dynamic rather than fixed. The system continuously measures or determines the actual antenna height above the implement ground point and uses this dynamically updated value in the roll error compensation calculations. This dynamic adjustment allows the steering system to adapt to changing conditions (such as different implements, terrain variations, or antenna mounting differences) and maintains both stability and accuracy by using the current actual height in all compensation computations.
3Ease of operation
If the tractor attempts to compensate for sideways downhill slippage by crabbing uphill, then yaw error results from the lead length of the GNSS antenna in front of the effective implement ground point and the uphill crabbing angle
Solution Approach 1:
The patent implements feedback by continuously measuring the actual position of the implement ground point using GNSS and comparing it with the desired path. The system then calculates the crosstrack error and uses this feedback to determine the required crabbing angle and yaw compensation. By measuring the actual roll angle and using it to compute the lateral displacement and yaw effects, the system creates a closed-loop feedback mechanism that automatically adjusts for sidehill conditions, eliminating the need for manual crabbing corrections and maintaining tracking accuracy.
Data Source
AI summary
An apparatus and method using GNSS for dynamically adjusting side-to-side positioning of a farm implement along a geographical path.