Refueling Boom Trajectory Planning Around Receiver Keep-Out Zones

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Solution Overview

Problem

Existing air-to-air refueling systems face challenges in accurately guiding a refueling boom to a receiver aircraft without colliding with obstacles due to limited visibility and reliance on line-of-sight trajectory planning, which can lead to potential collisions with the receiver's structural components.

Innovation Solution

Employing predictive artificial potential fields (APFs) to calculate a planned trajectory for the refueling boom, using 3D models and sensor data to avoid collisions by shaping the boom's path through free space, guided by attractive and repulsive forces to ensure safe engagement with the receiver's fuel receptacle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If line-of-sight trajectory planning is used for boom guidance, then the control system is simple and easy to operate, but the boom may collide with receiver structural components due to limited visibility

Engineering Contradiction:
Improvecollision avoidanceVSAvoidtrajectory planning system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces artificial potential fields as an intermediary computational layer between the boom control system and the physical environment. These fields act as a virtual mediator that processes spatial relationships and generates collision-free trajectories without requiring direct line-of-sight visibility, thus improving reliability while maintaining manageable system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a three-dimensional boundary model (virtual copy) of the receiver aircraft that includes all structural components. This digital replica allows the trajectory planning system to simulate and plan boom paths in the virtual model, ensuring collision avoidance before executing actual movements, thereby improving safety without proportionally increasing physical system complexity

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If the control station is positioned aft of the cockpit for operator safety, then operator protection is improved, but direct visual monitoring of the boom and receiver is lost

Engineering Contradiction:
Improveoperator safetyVSAvoidvisual feedback
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent replaces the mechanical visual monitoring system (direct line-of-sight from control station) with a computational vision system using artificial potential fields and 3D boundary models. This substitution allows operators to remain in safe positions while the computational system processes spatial data and generates trajectory information, converting physical visual requirements into computational processing

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces computational models and algorithms as intermediaries between the physical refueling operation and the operators. The artificial potential fields and 3D boundary models serve as virtual intermediaries that translate complex spatial relationships into actionable trajectory guidance, compensating for the loss of direct visual feedback while maintaining operator safety

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If a straight-line trajectory is used for boom movement, then the fuel transfer process is fast and efficient, but collisions with receiver features are more likely

Engineering Contradiction:
Improvefuel transfer speedVSAvoidcollision-free operation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent performs preliminary computational analysis by creating three-dimensional boundary models of the receiver and calculating artificial potential fields before boom movement. This advance preparation identifies collision risks and pre-computes safe trajectory adjustments, allowing the boom to follow efficient paths while avoiding obstacles, thus maintaining productivity without sacrificing reliability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent transforms the static straight-line trajectory into a dynamic adaptive path using artificial potential fields. The trajectory continuously adjusts based on real-time spatial relationships between the boom and receiver, allowing the system to optimize for both speed and safety by dynamically selecting the most efficient collision-free path rather than following a fixed geometric line

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS12486040B2Artificial potential field-based boom guidance for automated air-to-air refueling
Publication Date: 2025.12.02 THE BOEING CO
  • US12486040B2 patent drawing
  • US12486040B2 patent drawing
  • US12486040B2 patent drawing

AI summary

A trajectory planning system for a refueling boom includes a human-machine interface (“HMI”) device and an electronic control unit (“ECU”). The HMI device outputs electronic control signals, in response to which the ECU performs a method. The ECU accesses a three-dimensional (“3D”) boundary model of the receiver and a 3D model of the boom. The ECU calculates a boom-to-receiver relative position using the models and sensor data, and a planned trajectory between a boom tip and a receptacle on the receiver. The trajectory is calculated using the boom-to-receiver relative position and predictive artificial potential fields. A point is found on a baseline trajectory farthest from a straight line between the receptacle and boom tip, which is recorded as a temporary goal. The planned trajectory avoids contact between the boom and receiver features. The ECU executes a control action using the planned trajectory.