Experimental evaluation of the Smart Spring for helicopter vibration suppression through blade root impedance control

摘要

Most active approaches for helicopter rotor vibration suppression require active material based actuators to provide large force and displacement simultaneously. However, successful implementation has been hindered by the performance limitations of the actuators. The Smart Spring is a unique structural impedance control approach that employs piezoelectric stack actuators efficiently to suppress blade vibration. This paper presents the principles of the Smart Spring to control helicopter blade root impedance to suppress vibration. Open loop experiments were conducted to identify the impedance properties of proof-of-concept Smart Spring hardware before and after installation of a helicopter blade section. An adaptive algorithm was implemented using the Matlab xPC Target platform to control blade impedance properties. Closed-loop tests were conducted on the blade section using a mechanical shaker to provide representative disturbances. Significant reduction in blade vibration and torque reaction force was achieved simultaneously. Experimental results indicated that the Smart Spring is a promising approach for helicopter individual blade control applications to suppress rotor vibration.