Design and experimental verification of a smart piezoelectric pitch link for vibration attenuation

Author(s)

Marcel Araujo Clementino

• Document type: Doctoral Thesis
• Press: São Carlos.
• Institution: Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD)
• Defense date: 2019-02-06

Examining board members

Carlos De Marqui Junior; Luiz Carlos Sandoval Goes; Paulo Jose Paupitz Goncalves; Leopoldo Pisanelli Rodrigues de Oliveira; Domingos Alves Rade

• Advisor: Carlos De Marqui Junior; Fred Nitzsche

Abstract

Piezoelectric materials have been extensively employed for vibration reduction purposes in different fields of engineering. In general, the vibration control systems are grouped as active and passive systems, using the inverse and direct piezoelectric effect, respectively. Recently, these materials have been connected to switching circuits to perform the nonlinear management of the electrical output (voltage/current), resulting in the semi-active and semi-passive controllers. Among all configurations presented in the literature, some might be directly compared to mechanical systems used for vibration reduction in helicopters, likewise the Active Pitch Link (APL), which employs the combination of springs to control the variation of the structural stiffness. Although the APL device provides the attenuation of relevant vibration frequencies in a helicopter, the dependence on an external voltage source and possible mechanical failures (due to constant friction) are pointed out as drawbacks of the system. Therefore, this work reports on the design and experimental tests of a new smart pitch link system using piezoelectric materials for vibration attenuation. Different synchronized switching control techniques were investigated for vibration attenuation at a target frequency. A series of experiments are reported, including bench top vibration tests and whirl tower tests. The new configuration proposed here refers to a solid-state electromechanical system to address the issues of the mechanical active pitch link and provide a similar vibration attenuation performance (AU)

• FAPESP's process: 13/15264-3 - Design and Experimental Verification of a Semi-Active Pitch Link for Helicopter Vibration Attenuation
• Grantee: Marcel Araujo Clementino
• Support Opportunities: Scholarships in Brazil - Doctorate