Rotating Optical Flow Sensing for Near-Aircraft Obstacle Distance
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Solution Overview
Problem
Existing optical flow techniques in aircraft obstacle detection systems are ineffective in measuring distances to small obstacles near the aircraft, especially when the aircraft is stationary or moving slowly, as they rely solely on the aircraft's movement and struggle to detect obstacles on the axis of travel.
Innovation Solution
Measuring optical flow radially while rotating along a circle, using a device with an optical flow sensor mounted eccentrically on a rotating element, such as the ends of a helicopter rotor blade, to determine obstacle distance from the amplitude of optical flow, rotational speed, and radius, while compensating for rotational components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical flow techniques are used for obstacle detection in stationary or slowly moving aircraft, then the system can detect obstacles using the aircraft's movement, but small obstacles near the aircraft and obstacles on the axis of travel cannot be detected
Solution Approach 1:
The patent applies the dynamics principle by mounting the optical flow sensor on a rotating element (such as a helicopter rotor blade) that continuously rotates at a determinable rotational speed. This transforms the stationary or slowly moving aircraft into a dynamic measurement system where the sensor moves along a circular path, generating sufficient optical flow to detect small obstacles and those on the axis of travel that would otherwise be undetectable
Solution Approach 2:
The rotating element serves as an intermediary between the aircraft and the optical flow sensor. By mounting the sensor on the rotating element at an eccentric point, the system creates a tangential velocity component that enables distance measurement without requiring the aircraft itself to move, thus solving the problem of detecting obstacles when the aircraft is stationary or moving slowly
2Measurement precision
If the optical flow sensor is mounted on the rotating element, then tangential velocity component is introduced for better obstacle detection, but rotational components must be compensated
Solution Approach 1:
The patent implements feedback by using a gyroscopic system mounted in the aircraft to measure rotational components, which are then used to compensate the optical flow measurements. This feedback mechanism allows the system to distinguish between optical flow caused by aircraft rotation and optical flow caused by obstacle proximity, enabling accurate distance measurement despite the added complexity of rotational compensation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for precise detection of obstacles, including small ones near the aircraft, by introducing a tangential velocity component in the optical flow, enabling accurate distance measurement and orientation determination, even when the aircraft is stationary or moving slowly.
Implementation Method 1
an optical flow sensor configured to measure an optical flow at an eccentric point of the rotating element
Data Source
AI summary
A system for measuring the distance of an obstacle, in which an optical flow is measured radially while rotating along a circle in a plane intersecting the obstacle; and the distance of the obstacle is determined according to the amplitude of the optical flow, the radius of the circle, and the speed of rotation.