Differential Pressure Altitude Sensing for Multicopter Ground Effect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current altitude estimation techniques for multicopters, such as vision and wave-based methods, are inadequate for vertical takeoff and landing (VTOL) operations due to their inability to sense ground effect and are often heavy and expensive, making them unsuitable for lightweight and resource-constrained VTOL multicopters.
Innovation Solution
The use of differential pressure sensors to measure airflow interference and isolated airflow, combined with a generalized flow model and non-linear Bayesian filtering, to accurately estimate altitude in the presence of ground effect, allowing for precise altitude control during VTOL operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vision or wave-based altitude estimation techniques are used, then altitude can be estimated, but the system becomes heavy and expensive, and cannot sense ground effect
Solution Approach 1:
The patent replaces vision-based and wave-based altitude estimation systems with a mechanical/differential pressure sensing system. The differential pressure sensor measures pressure differences caused by rotor downwash and ground effect, providing altitude estimation without the weight and cost of cameras, LIDAR, or radar systems.
Solution Approach 2:
The system uses the multicopter's own rotor downwash airflow as the measurement source. The differential pressure sensor measures the interaction between the rotor-generated airflow and the ground, eliminating the need for external sensing systems that would add weight and complexity.
2Measurement precision
If vision or wave-based altitude estimation techniques are used, then altitude can be estimated, but the system cannot detect ground effect and becomes unsuitable for VTOL operations
Solution Approach 1:
The patent employs a differential pressure sensor that measures pneumatic pressure differences in the airflow field. The sensor detects changes in air pressure caused by the interaction between rotor downwash and the ground, enabling direct measurement of ground effect phenomena that other sensing methods cannot detect.
Solution Approach 2:
The differential pressure sensor acts as an intermediary that translates physical airflow interactions into measurable electrical signals. The sensor measures the intermediate parameter (pressure difference) that results from the interaction between rotor downwash and ground, providing indirect but accurate measurement of ground effect.
3Reliability
If differential pressure sensors are used to measure airflow, then ground effect can be detected, but rotor interference must be distinguished from ground effect
Solution Approach 1:
The patent segments the differential pressure measurements into distinct components: one measuring rotor interference effects and another measuring ground effect. By positioning sensors to capture different aspects of the airflow field, the system can separate and analyze each effect independently through signal processing.
Solution Approach 2:
The system uses feedback from multiple differential pressure sensors to continuously monitor and distinguish between rotor interference and ground effect. By comparing measurements from different sensor locations and using the known rotor characteristics, the system can feedback-correct the altitude estimation to account for rotor interference while isolating true ground effect signals.
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 approach provides accurate and lightweight altitude estimation, enabling safe and efficient vertical takeoff and landing operations by effectively distinguishing between rotor interference and ground effect, thus improving the reliability of multicopter flight control systems.
Implementation Method 1
a sensor dataset from a differential pressure sensor that measures an interference between a rotor downwash of the multicopter and an ambient airflow
Implementation Method 2
vision and wave-based altitude estimation techniques do not sense the presence of ground effect and so would not work well for vertical takeoff and landing (VTOL) multicopters (which generate large amounts of downward airflow) when such aircraft are operating near the ground
Data Source
AI summary
An interference sensor dataset associated with interference between airflows from at least two rotors in a multicopter and a first isolated sensor dataset and a second isolated sensor dataset which are associated with isolated airflows from a first rotor and a second rotor in the multicopter, respectively, are received. A generalized flow model associated with a generalized rotor is received. An altitude for the multicopter is generated based at least in part on the interference sensor dataset, the first isolated sensor dataset, the second isolated sensor dataset, and the generalized flow model, including by using a non-linear filter that builds a consolidated probability function associated with altitude that reconciles the interference sensor dataset, the first isolated sensor dataset, and the second isolated sensor dataset with the generalized flow model.