Rotorcraft Antivibration Control With Phase-Based Mass Tuning
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Solution Overview
Problem
Existing antivibration systems for rotorcraft, such as SARIB suspensions, face challenges in quickly and reliably adjusting inertial masses to optimize antiresonance across varying flight configurations, leading to slow convergence and inability to adapt in real-time, especially during transient stages.
Innovation Solution
An antivibration system with tuned-mass dampers, motor members, and accelerometers that calculate and adjust the phase angle between dynamic excitation and resulting vibration, allowing for rapid and precise positioning of inertial masses along the longitudinal axis, using threshold values to control motor movement and maintain optimal antiresonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive SARIB suspension adjustment methods are used, then the system can be implemented with simple mechanical components, but the adjustment convergence is slow and cannot adapt in real-time during transient flight stages
Solution Approach 1:
The patent implements a feedback control system where accelerometers mounted on the fuselage measure vibration levels, and a control unit processes these signals to automatically adjust the inertial mass position in the tuned-mass damper. This closed-loop feedback enables real-time adaptation during flight, resolving the contradiction between reliable convergence and adjustment time by continuously monitoring vibration and making corrective adjustments without pilot intervention.
Solution Approach 2:
The antivibration system performs self-adjustment through automated control logic that processes accelerometer signals and actuates the inertial mass positioning mechanism without external input. The system serves itself by autonomously detecting vibration conditions and correcting its own performance, eliminating the need for manual adjustment procedures and enabling rapid adaptation during transient flight stages.
2Adaptability or versatility
If manual adjustment procedures are used, then the system structure remains simple, but the system cannot maintain optimal antiresonance during varying flight configurations
Solution Approach 1:
The patent transforms the static, manually-adjusted antivibration system into a dynamic system that automatically adapts to changing flight conditions. The inertial mass position is no longer fixed but can be dynamically repositioned using actuators controlled by a microprocessor that receives real-time vibration data from accelerometers, enabling the system to maintain optimal antiresonance across varying flight configurations.
Solution Approach 2:
The patent replaces manual mechanical adjustment procedures with an automated electromechanical control system. Instead of requiring pilots to manually reposition inertial masses based on flight phase, the system uses electronic sensors (accelerometers) and actuators controlled by a microprocessor to automatically adjust the damper configuration, trading increased device complexity for superior adaptability.
3Reliability
If the inertial mass is repositioned during flight, then the antiresonance can be optimized for different flight stages, but the adjustment process takes too long to converge
Solution Approach 1:
The control unit continuously monitors vibration signals from accelerometers and uses this feedback to determine when optimal antiresonance has been achieved. The system adjusts the inertial mass position and monitors the resulting vibration changes, automatically stopping the adjustment process once the optimal configuration is reached, thereby ensuring reliable optimization while minimizing adjustment time through intelligent termination of the tuning process.
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
Enables quick and reliable adjustment of inertial masses to ensure consistent comfort and fatigue strength across all flight stages, even during transient conditions, by identifying and responding to phase angle changes in real-time.
Implementation Method 1
The principle of the SARIB suspension is to create antiresonance by superposing the inertial effects of the damper on the return forces generated by the resilient return means for the purpose of diminishing or even eliminating the dynamic excitation.
Implementation Method 2
a tuned-mass damper associated with a respective MGB bar and comprising a mass support secured at one of its ends to a suspension member and provided at its other end with an inertial mass, the damper being characterized by inertia that is obtained for the most part by said inertial mass
Implementation Method 3
a suspension member including resilient return means such as a spring characterized by an appropriate stiffness, working in traction/compression, or indeed in twisting, connecting the bottom portion of the MGB to the fuselage
Implementation Method 4
at least one first accelerometer arranged on the fuselage of the rotorcraft to measure in at least one direction resulting vibration to which the fuselage is subjected
Implementation Method 5
motor members for controlling movement in translation of the inertial mass along said longitudinal axis La-Ld
Data Source
AI summary
A rotorcraft having an antivibration system, the antivibration system being arranged at the interface between a fuselage of the rotorcraft and a casing of a main power transmission gearbox, or “MGB”, in order to transmit rotary motion generated by an engine of the rotorcraft to a main rotor providing the rotorcraft at least with lift, and possibly also propulsion, the antivibration system including calculation means for analyzing as a function of time the dynamic excitation and the resulting vibration transmitted to the fuselage of the rotorcraft.