Autonomous Work Vehicle Steering Using Predicted Path Deviation
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Solution Overview
Problem
Existing autonomous work vehicles are unstable in navigation due to excessive steering adjustments when deviating from a target travel path, leading to inadequate correction and continued deviation.
Innovation Solution
A control device that calculates an estimated vehicle position based on current position, speed, and travel direction to predict and adjust steering, reducing excessive steering and maintaining path stability by combining lateral and directional deviation corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the steering mechanism is controlled to reduce lateral separation distance by further reducing the distance between the front portion and the target point, then the vehicle can correct its position on the target travel path, but excessive steering adjustments are generated causing instability in autonomous travel
Solution Approach 1:
The system calculates an estimated vehicle position in advance based on current position, speed, and travel direction before generating steering commands. This preliminary position estimation allows the control system to anticipate the vehicle's future location and generate appropriate steering adjustments in advance, preventing excessive or reactive steering corrections that would cause instability
Solution Approach 2:
The system continuously monitors the deviation between the estimated vehicle position and the target travel path, and adjusts steering commands based on this feedback. By using the estimated position rather than just the current position, the feedback loop becomes more accurate and stable, reducing oscillations and excessive steering adjustments
2Adaptability or versatility
If the target steering amount is computed from positional deviation and directional deviation with weighting factors, then the steering control can be adjusted, but the vehicle remains unstable when deviating from the target path due to inadequate correction
Solution Approach 1:
The system performs preliminary calculation of the estimated vehicle position considering current speed and travel direction before computing the target steering amount. This advance estimation ensures that the steering control is based on where the vehicle will be, not just where it is, improving the reliability of path following
Solution Approach 2:
The system changes the parameter used for steering calculation from static current position to dynamic estimated position that incorporates speed and direction. This parameter change makes the steering control more reliable by accounting for the vehicle's motion state, ensuring adequate correction even when deviating from the target path
Data Source
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AI summary
A control device for a work vehicle configured to travel autonomously includes: a vehicle position calculating section 80 configured to calculate a vehicle position; a travel direction calculating section 81 configured to calculate a travel direction, the travel direction being a front-back direction of the vehicle body; a steering state obtaining section 56 configured to obtain data on a steering state; a vehicle position estimating section 61 configured to calculate an estimated vehicle position at which the work vehicle is to be present after performing predetermined travel from the vehicle position of the work vehicle; a deviation calculating section 62 configured to calculate a deviation of the work vehicle at the estimated vehicle position from the target travel path; a target steering amount calculating section 63 configured to calculate a target steering amount on the basis of the deviation; and an autonomous travel control section 511 configured to control steering on the basis of the target steering amount.