Egospace Data Structure for UAV Obstacle Avoidance

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Solution Overview

Problem

Micro air vehicles (MAVs) face challenges in high-speed autonomous flight in cluttered environments due to power and size restrictions, limiting sensing and computational resources for obstacle detection and motion planning, which existing technologies have not adequately addressed.

Innovation Solution

The development of an egospace data structure that compactly represents range measurements from multiple sensors, enabling efficient motion planning and obstacle avoidance by generalizing depth image obstacle representations and allowing for temporal fusion of depth maps, thereby improving collision-checking and trajectory generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If vision-based obstacle detection is used to satisfy sensing constraints, then power requirements are reduced and weight is minimized, but computational resources for real-time processing in cluttered environments become insufficient

Engineering Contradiction:
Improvepower consumptionVSAvoidreal-time processing capability
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent segments the environment representation into discrete depth bins along the flight path, creating a simplified one-dimensional depth map rather than processing full 3D point clouds. This segmentation reduces computational complexity while maintaining essential obstacle detection capabilities for real-time operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts only the critical depth information needed for collision avoidance by projecting 3D range data onto a one-dimensional depth map along the vehicle's forward axis. This extraction removes unnecessary spatial details while preserving the essential obstacle distance information required for real-time decision-making

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If binocular stereo vision is used to populate occupancy grid world models, then forward-looking obstacle detection is achieved, but computational load and memory requirements increase

Engineering Contradiction:
Improveobstacle detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transforms 3D spatial occupancy grid data into a one-dimensional depth map representation along the flight path. This dimensionality reduction projects complex three-dimensional obstacle information onto a single axis, dramatically reducing computational and memory requirements while maintaining the ability to detect forward obstacles

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If disparity space representation is used for fast collision-checking, then trajectory evaluation speed is improved, but the field of regard is limited and sensor fusion becomes complex

Engineering Contradiction:
Improvetrajectory evaluation speedVSAvoidfield of regard
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal depth map representation that serves multiple functions: it enables fast collision checking like disparity space, accommodates any sensor type (stereo, monocular, active range sensors), and provides a common framework for sensor fusion. The one-dimensional depth map along the flight path becomes a multi-functional data structure that simplifies rather than complicates sensor integration

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If traditional motion planning methods are used in configuration space, then collision-free paths can be generated, but computational time increases and real-time performance is compromised

Engineering Contradiction:
Improvecollision-free path generationVSAvoidcomputational time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the essential collision information into a simplified one-dimensional depth map that directly represents obstacles along the flight path. This extraction eliminates the need for complex configuration space computations by providing direct depth measurements, enabling real-time collision-free path generation through simple comparison operations

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the representation parameters from full 3D configuration space coordinates to a one-dimensional depth parameter along the flight path. This parameter transformation simplifies the motion planning problem by reducing the dimensionality of the search space while maintaining the ability to generate collision-free trajectories

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS10665115B2Controlling unmanned aerial vehicles to avoid obstacle collision
Publication Date: 2020.05.26 CALIFORNIA INST OF TECH
  • US10665115B2 patent drawing
  • US10665115B2 patent drawing
  • US10665115B2 patent drawing

AI summary

A method, device, framework, and system provide the ability to control an unmanned aerial vehicle (UAV) to avoid obstacle collision. Range data of a real-world scene is acquired using range sensors (that provide depth data to visible objects). The range data is combined into an egospace representation (consisting of pixels in egospace). An apparent size of each of the visible objects is expanded based on a dimension of the UAV. An assigned destination in the real world scene based on world space is received and transformed into egospace coordinates in egospace. A trackable path from the UAV to the assigned destination through egospace that avoids collision with the visible objects (based on the expanded apparent sizes of each of the visible objects) is generated. Inputs that control the UAV to follow the trackable path are identified.