Work Vehicle Steering Control With Adaptive Angle Limiting
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Solution Overview
Problem
Conventional automatic steering systems for work vehicles face challenges in accurately controlling steering during turning travel, leading to control overshoot and increased computing loads due to rapid changes in turning radius, which require high-cost computing functions and result in inefficient steering operations.
Innovation Solution
An automatic steering system that limits the steering amount using a steering amount limiter, prohibits excessive steering operations, and adjusts the steering limit based on the vehicle's location within the turning route, employing simple arithmetic to calculate locational and directional shifting amounts, and utilizes PID or PI control methods to suppress control hunting and ensure smooth turning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If steering control is performed with a large steering angle to correct significant directional shifting, then the directional deviation is corrected faster, but control overshoot occurs and turning travel cannot be performed smoothly
Solution Approach 1:
The patent applies dynamics by making the steering angle correction adaptive rather than fixed. The steering angle is dynamically adjusted based on the current directional shifting amount, allowing the system to apply larger corrections when needed while preventing overshoot when the vehicle is closer to the target direction, thereby ensuring smooth turning travel throughout the correction process
Solution Approach 2:
The patent implements feedback control by continuously monitoring the directional shifting amount and using this information to adjust the steering angle correction. The system calculates the current directional deviation, determines an appropriate correction amount based on this feedback, and applies the correction iteratively, which prevents control overshoot while maintaining effective correction speed
2Measurement precision
If tangent vector calculation is used to determine locational and directional shifting amounts, then accurate steering control is achieved, but computing load increases and computing time lengthens
Solution Approach 1:
The patent replaces the expensive and complex tangent vector calculation method with a simpler, computationally lighter alternative that achieves the same measurement precision. By using basic trigonometric relationships and coordinate transformations instead of tangent vector computations, the system obtains accurate locational and directional shifting amounts with significantly reduced computing load and simpler hardware requirements
Data Source
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AI summary
An automatic steering system for a work vehicle includes: a steering travel apparatus for performing leftward turning based on a leftward steering amount with respect to a straight-forward direction and performing rightward turning based on a rightward steering amount with respect to a neutral position; a subject vehicle location calculator 55 for calculating a location of a subject vehicle; a locational shifting calculator 57 for calculating locational shifting from the travel route and the location of the subject vehicle; a vehicle body direction calculator 56 for calculating a vehicle body direction that indicates a direction of a vehicle body; a directional shifting calculator 58 for calculating directional shifting from the travel route and the vehicle body direction; a steering amount calculator 41 for calculating a first steering amount, which is a steering amount for correcting the locational shifting and the directional shifting, based on the locational shifting and the directional shifting; and a steering amount limiter 42 for limiting the first steering amount based on a second steering amount, which is the steering amount at present.