Swashplateless Rotor Blade Control via Azimuthal Position

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Solution Overview

Problem

Conventional rotor systems rely on swashplates to control rotor blade pitch, limiting independent control of each blade, which is not feasible in swashplate-less rotor systems.

Innovation Solution

A method and system that determine the azimuthal position of a rotor assembly, generate separate blade control signals for each rotor blade by combining sine and cosine values of the azimuthal position with lateral, longitudinal, and collective command values, allowing independent control of each rotor blade without a swashplate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a swashplate is used to control rotor blade pitch, then collective and cyclic control is achieved, but individual independent control of each blade is limited

Engineering Contradiction:
ImproveIndependent blade control capabilityVSAvoidSwashplate mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention divides the rotor control system into independent blade-level control units. Each rotor blade is equipped with its own actuator and control electronics, allowing individual blade pitch control. The control system segments the collective and cyclic control commands into blade-specific control signals based on azimuthal position, enabling independent adjustment of each blade's pitch angle without mechanical coupling through a swashplate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention replaces the mechanical swashplate system with an electronic control system. Instead of using a rotating swashplate with pitch links to transmit mechanical control forces to each blade, the system uses electronic sensors to detect azimuthal position and electronic actuators (such as electric motors or servos) to adjust blade pitch independently. This substitution eliminates the mechanical complexity of the swashplate while achieving superior control flexibility.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a swashplate system is used, then mechanical pitch control is achieved, but control flexibility and precision are reduced

Engineering Contradiction:
ImproveBlade position control precisionVSAvoidControl flexibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention incorporates feedback mechanisms through azimuthal position sensors that continuously monitor the rotational position of each rotor blade. This feedback information is fed back to the control system, which uses it to calculate the appropriate pitch control commands. The closed-loop feedback enables precise control by constantly comparing the actual blade position with the desired position and making real-time adjustments to eliminate errors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention implements dynamic control by continuously adjusting blade pitch based on real-time azimuthal position and flight conditions. Unlike the static mechanical linkages of a swashplate, the electronic control system can dynamically modify control signals at any point in the rotor rotation cycle. This allows for phase-adjusted control where each blade can be optimized independently for its current position, enhancing both precision and flexibility.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2848525B1Controlling Rotor Blades of a Swashplateless Rotor
Publication Date: 2017.10.04 SIKORSKY AIRCRAFT CORP
  • EP2848525B1 patent drawingFigure 1
  • EP2848525B1 patent drawingFigure 2
  • EP2848525B1 patent drawingFigure 3

AI summary

Controlling rotor blades (123-126) of a rotor assembly (121) includes determining an azimuthal position of a rotor assembly (121) and identifying a lateral control command value, a longitudinal control command value and a collective control command value of a rotor assembly control system. A sine value (SIN) and a cosine value (COS) of the azimuthal position are calculated and separate blade commands signals (1-4) are generated for each separate blade of the rotor assembly to control a position of each blade (123-126) independent of each other blade. The blade command signals (1-4) are generated based on combining the sine and cosine values of the azimuthal position with the lateral control command value, the longitudinal control command value and the collective control command value.