Active feedback control of multiple waves in helicopter gearbox support struts

A study on active control of multiple waves in finite-length struts is presented. Modeling of such an active strut system that supports the gearbox over the helicopter fuselage is focused on in the study. An integrated mechanics model with feedback control of waves called the active spectral element model (ASEM) is used. The formulation allows one to account for coupling between longitudinal and flexural waves, dynamics of point or distributed sensors and dynamics of point or distributed actuators. Effects of finite strut and actuator dynamics are taken into account. Numerical investigations into collocated as well as non-collocated velocity feedback control of multiple axial, flexural and axial-flexural coupled waves are presented. Efficient computation using ASEM provides a powerful tool to study the sensitivity of the feedback parameters and various sensor-actuator configurations.