Test and Simulation of an Active Vibration Control System for Helicopter Applications

Abstract

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

Airframe Vibration Reduction for an Unmanned Lift-Offset Compound Helicopter Using Active Vibration Control System

“…The AVCS reduces the airframe vibration response by minimizing the sum of the airframe vibration and vibration cancellation signals. The AVCS consists of force generators to produce vibration cancellation forces, accelerometers, and a closedloop feedback controller [5][6][7].…”

“…Although the AVCS has successfully demonstrated the airframe vibration reduction of lift-offset compound helicopters [3,4,7], conventional helicopters (Korean utility helicopter [5,6], UH-60 M [8] and S-92 [9]), and tiltrotor aircraft (V-22 [10]), there have been no studies on using AVCS to reduce the airframe vibration response of a liftoffset compound helicopter, which has wings as well as a lift-offset coaxial rotor. The wing vibration of a tiltrotor aircraft, which is a convertible aircraft with proprotors and Fig.…”

Active Airframe Vibration Control Simulations of Lift-offset Compound Helicopters in High-Speed Flights

“…5. Nondimensionalized X2TD rotor hub vibratory loads at 250 knots [9] (1P = 395 RPM) [5] ). CRFG의 제원은 Sikorsky 社의 시뮬레이션 연구 결과 를 [4] 참고하여 사용된 6개의 CRFG의 총 중량이 기체 의 총 중량의 1.3 %가 되도록 가정하였다.…”

“…CRFG의 제원은 Sikorsky 社의 시뮬레이션 연구 결과 를 [4] 참고하여 사용된 6개의 CRFG의 총 중량이 기체 의 총 중량의 1.3 %가 되도록 가정하였다. 이와 더불 어 참고문헌 [5,16] [4] .…”

A Time‐Domain Active Vibration Control Algorithm for Helicopter Based on a Prior Error Channel Identification Strategy

“…Even so, because of its own characteristic, the update speed of frequency-domain algorithm is slow, and its adaptability is insufficient when helicopters are in maneuvering flight, while time-domain algorithm has the advantage of quick update speed and does not need to change the signal form time-domain to frequency-domain. In recent years, some researchers have applied time-domain algorithm in helicopters like EC135, EC145, and SURION [15][16][17].…”