Multi-Rotor Airspeed Calculation Without Dedicated Sensors
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Solution Overview
Problem
Multi-rotor aerial vehicles lack accurate airspeed measurement and airspeed envelope protection due to interference from turbulent airflow and high installation costs of traditional airspeed sensors, which are not integrated into control laws, posing safety and cost challenges.
Innovation Solution
A method and device for calculating airspeed using known attitude and acceleration measurements without additional hardware sensors, employing a mathematical model and Newton iteration algorithm to determine real-time airspeed, and implementing airspeed envelope protection through dynamic principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional airspeed sensors based on dynamic/static pressure principles are installed on large multi-rotor aerial vehicles, then airspeed measurement capability is improved, but the sensors are susceptible to interference from turbulent airflow caused by multiple propellers and require significant structural installation costs
Solution Approach 1:
The patent replaces traditional mechanical airspeed sensors with a computational approach using a mathematical model that calculates airspeed based on acceleration measurements from inertial sensors and attitude angles. This substitution eliminates the need for physical sensors that are susceptible to turbulent airflow interference from propellers.
Solution Approach 2:
The patent introduces a mathematical model as an intermediary that processes acceleration measurements and attitude information to derive airspeed. This intermediary computation layer avoids direct measurement in the turbulent airflow environment, solving the interference problem while maintaining measurement capability.
2Measurement precision
If traditional airspeed sensors are installed on large multi-rotor aerial vehicles, then airspeed measurement is achieved, but manufacturing, debugging, and maintenance costs increase
Solution Approach 1:
The patent enables the flight control system to self-calculate airspeed using existing acceleration and attitude measurements that are already collected for flight control purposes. This self-service approach eliminates the need for separate airspeed sensing hardware, reducing manufacturing, debugging, and maintenance costs while maintaining airspeed measurement capability.
Solution Approach 2:
The patent makes the existing inertial measurement system multi-functional by using acceleration and attitude data for both flight control and airspeed calculation. This universal use of existing sensors eliminates the need for dedicated airspeed sensors, reducing overall system cost and complexity.
3Measurement precision
If dynamic/static pressure-based airspeed meters are used on general multi-rotor aerial vehicles, then airspeed measurement may be achieved, but environmental interference from installation conditions and differences in control methods reduce reliability
Solution Approach 1:
The patent replaces mechanical airspeed meters with a computational method that uses acceleration and attitude measurements. This substitution improves reliability by eliminating the susceptibility to environmental interference and installation condition variations that affect traditional sensors on multi-rotor vehicles.
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
Accurate airspeed calculation and envelope protection are achieved without hardware sensors, reducing manufacturing, debugging, and maintenance costs while ensuring flight safety.
Implementation Method 1
k1(θ)·V+k2(θ)·V2+k3(θ)·V3=mg tan θ−max, where m is the mass, g is the gravitational acceleration, θ is the tilt angle, ax is the acceleration, V is the airspeed, and k1(θ), k2(θ), k3(θ) are preset first-order, second-order, and third-order drag coefficient functions, respectively
Data Source
AI summary
A method, device, and computer-readable storage medium for multi-rotor airspeed calculation and airspeed envelope protection is disclosed. The airspeed calculation method includes: establishing an airspeed calculation mathematical model; defining a function ƒ(V) based on the airspeed calculation mathematical model for each calculation cycle, and combining real-time measurements of tilt angle θ and acceleration ax, using the Newton iteration algorithm to solve the root of the equation ƒ(V)=0 in real time as the real-time airspeed V to control flight of the multi-rotor. An airspeed calculation scheme is implemented based on dynamics principles, fully utilizing dynamics principles and combining the unique control methods of multi-rotors. Without adding hardware sensors, it uses known attitude measurements and acceleration measurements as algorithm inputs, and calculates airspeed data with sufficient accuracy through software algorithms, simplifying the hardware structure, reducing the risk of electrical failure, and saving manufacturing, debugging, and maintenance costs.