Multicopter Rotor Inversion for Failure Recovery
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Solution Overview
Problem
Multicopters with more than four rotors face significant losses in lift and maneuverability when a rotor fails, as existing redundancy methods primarily involve throttling remaining rotors, leading to reduced thrust and limited maximum take-off weight, making them impractical for applications like aerial photography.
Innovation Solution
The method involves controlling at least one remaining rotor to temporarily rotate in the opposite direction of its intended rotation, generating negative thrust, which allows for increased total thrust and improved maneuverability by compensating for failed rotors through a control matrix and optimization process, enabling higher take-off weights and enhanced flight characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If remaining rotors are controlled to compensate for a failed rotor by reducing their power output, then the multicopter maintains flight capability, but the resulting lift and maneuverability are dramatically reduced
Solution Approach 1:
The patent applies reverse rotation of remaining rotors to compensate for a failed rotor. Instead of simply reducing power output of remaining rotors, the invention rotates at least one remaining rotor in the opposite direction to generate negative thrust, which creates a torque that compensates for the lost lift and torque from the failed rotor. This inversion principle resolves the contradiction by maintaining flight capability while preserving or even improving lift and maneuverability compared to simple power reduction methods.
2Reliability
If remaining rotors are controlled to compensate for a failed rotor by reducing their power output, then the multicopter maintains flight capability, but the maximum takeoff weight is limited
Solution Approach 1:
The patent uses reverse rotation of remaining rotors to generate negative thrust, which creates a torque that compensates for the failed rotor. This approach allows the multicopter to maintain flight capability with a higher maximum takeoff weight compared to simple power reduction methods, because the negative thrust from reversed rotors creates a more efficient torque balance that preserves overall lift capacity.
3Shape
If rotors are arranged in a circle around the aircraft's center of gravity, then the multicopter has compact structure, but the failure of one rotor renders the multicopter no longer fully maneuverable
Solution Approach 1:
The patent applies reverse rotation of remaining rotors to compensate for the lost torque from a failed rotor in a circular arrangement. By rotating at least one remaining rotor in the opposite direction, the system generates a compensating torque that restores full maneuverability in roll, pitch, and yaw axes. This resolves the contradiction by maintaining the compact circular rotor arrangement while preserving complete maneuverability through the inversion principle.
4Shape
If a hexacopter uses coaxial propeller arrangement, then the structure is compact, but there is an efficiency loss that has not yet been taken into account
Solution Approach 1:
The patent applies reverse rotation of remaining rotors to compensate for a failed rotor in a coaxial hexacopter arrangement. By rotating at least one remaining rotor in the opposite direction, the system generates negative thrust that creates a torque to compensate for the failed rotor. This approach improves efficiency compared to simple power reduction methods, as the negative thrust from reversed rotors creates a more efficient torque balance that preserves overall lift capacity and reduces the efficiency loss associated with coaxial arrangements.
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 increases the lift capacity and maneuverability of multicopters in failure situations, particularly for hexacopters and octocopters, allowing for a higher maximum take-off weight and improved control decoupling, significantly enhancing their operational capabilities compared to prior art.
Implementation Method 1
each rotor (1 to 8) with a defined target direction of rotation... essentially generate thrust vertically downwards
Implementation Method 2
the failure of one rotor renders the hexacopter no longer fully maneuverable. In this case, a roll or pitch command generates a strong yaw moment
Data Source
AI summary
A method for improving the flight characteristics of a multicopter in a failure situation is provided, comprising providing a multicopter with at least six rotors, each with a defined target direction of rotation, and controlling the rotors so that they rotate according to their respective target directions. In the failure situation, at least one of the remaining rotors is controlled such that it rotates, at least temporarily, in the opposite direction to its target direction. Also provided is a multicopter with improved flight characteristics in a failure situation, comprising at least six rotors, each with a defined target direction of rotation, and control electronics with a stored control program that, in the failure situation, controls at least one of the remaining rotors so that it rotates, at least temporarily, in the opposite direction to its target direction.