Multi-Segment Turn Path Planning for Narrow Headlands

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Solution Overview

Problem

Existing path planning algorithms for autonomous vehicles do not effectively address the transition from one swath to another while minimizing crop damage, optimizing travel distance, and avoiding obstacles, particularly in scenarios where headlands are narrow.

Innovation Solution

Implement multi-segment path planning algorithms that allow vehicles to switch gears during turns and adapt trajectories to follow headland patterns, using features like move-to-start-of-turn, move-to-end-of-swath-before-turn, and move-to-beginning-of-next-swath-after-turn to minimize crop damage and optimize travel distance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a traditional single-segment turn path is used, then the turn can be completed quickly, but the vehicle may leave the headland boundary causing crop damage

Engineering Contradiction:
Improvecrop damageVSAvoidturn execution time
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The turn path is divided into multiple segments (first segment in forward gear, second segment in reverse gear) with an intermediate position between them. This segmentation allows the vehicle to confine the turn within the headland boundary while minimizing crop damage, as each segment can be optimized to stay within boundaries.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the headland width is narrow, then the available turning space is limited, but traditional paths require more space causing crop damage

Engineering Contradiction:
Improveheadland areaVSAvoidcrop damage
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

By dividing the turn into multiple segments with gear changes, the path can be compressed into narrower headland spaces. The intermediate position allows the vehicle to reverse direction within the confined headland area, enabling complete turns even in narrow spaces without damaging crops.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vehicle changes from forward gear to reverse gear (or vice versa) during the turn, using inversion of motion direction to accomplish the turn within limited space. This allows the vehicle to effectively use the same space twice (forward and reverse) to complete a turn that would otherwise require a larger area.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If the vehicle follows a path that does not confine to headland, then the turn can be completed with simpler control, but the vehicle damages crops

Engineering Contradiction:
Improvepath control simplicityVSAvoidcrop damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The path is segmented into controlled sections with defined intermediate positions. Each segment can be controlled independently to ensure boundary adherence, making it easier to maintain confinement within the headland while still achieving the turn objective.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If multi-segment trajectories with gear changes are used, then the turn can be confined within headland boundaries, but the control complexity increases

Engineering Contradiction:
Improvecrop damageVSAvoidpath control complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

While segmentation does increase control complexity, it enables precise boundary adherence. The control system manages this complexity by defining specific intermediate positions and gear change points, making the complex control manageable through structured path definition.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3903556B1Methods for path planning for multi-segment turns
Publication Date: 2025.08.13 PTX TRIMBLE LLC
  • EP3903556B1 patent drawingFigure 1
  • EP3903556B1 patent drawingFigure 2A~2C
  • EP3903556B1 patent drawingFigure 3A~3B

AI summary

A method of path planning for a vehicle includes receiving a request for a turn from a current swath to a next swath, receiving information of the current swath and information of the next swath, determining a trajectory of the turn based on the information of the current swath and the information of the next swath, and outputting the trajectory to a control system of the vehicle for executing the turn. The trajectory includes a first segment and a second segment. The first segment starts from a beginning position of the turn at the current swath and ends at an intermediate position; and the second segment starts from the intermediate position and ends at an ending position of the turn at the next swath. The vehicle changes from a forward gear to a reverse gear, or vice versa, as the vehicle transitions from the first segment to the second segment.