Multicyclic Vibration Control of a Helicopter Rotor with Active Twist Actuation

• Published in: International journal of aeronautical and space sciences Vol. 23; no. 2; pp. 303 - 314
• Main Authors: Kim, Do-Hyung, Hong, Seonghyun, Jung, Sung N.
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Aeronautical & Space Sciences (KSAS) 01.04.2022; 한국항공우주학회
• Subjects: Aerospace Technology and Astronautics; Engineering; Fluid- and Aerodynamics; Original Paper; 항공우주공학; Helicopter; Vibration reduction; Multicyclic control; Active twist
• ISSN: 2093-274X; 2093-2480
• DOI: 10.1007/s42405-022-00440-z

The vibration control performance of a Mach scaled Bo-105 rotor is evaluated using the active twist multicyclic control. The simulation data for the baseline flight condition are generated using CAMRAD II. A linear, quasi-static, frequency domain model with up to 6 multicyclic higher harmonic control inputs and 12 harmonic response outputs of non-rotating hub loads are identified offline by the least squared error estimate. The optimal control input for minimizing the quadratic performance function along with the output response to the optimal control are calculated. The vibration reduction performances with the obtained optimal control input are examined. The single harmonic control results show close agreement with the low vibration conditions by the amplitude and phase sweep method. When the multicyclic control is applied, the vibration reduction performance is improved compared to the single harmonic control case, and the hub vibration is reduced by up to 64%. A coupling of MATLAB and CAMRAD II is used to evaluate closed-loop multicyclic control systems. The coupled closed-loop analysis result shows good agreement with the simulation result using identified linear system model. The closed-loop control using the gradient descent algorithm shows excellent vibration reduction performance with the reduced vibration level converges to the optimal solution.