SBIR-STTR Award

In this project we propose to develop, test and demonstrate the potential of an Active Quiet Pillow for reducing interior noise in helicopter medical evacuation scenarios using numerical simulation and experimental testing. The potential of the Pillow design is expected to reduce the interior noise of a Blackhawk MEDEVAC helicopter from 106dB pink noise incident sound down to 90dBA at the patient?s ear. The innovation is based on a strategic combination of active and passive treatment elements in a pillow arrangement located under the patient?s head. In Phase I, numerical finite element models of the Active Quiet Pillow in a helicopter cabin interior will be developed including a modeled active noise system and passive noise treatment. The analysis will incorporate acoustic lining modeled by a surface impedance and the active speakers as baffled pistons embedded in the quiet pillow structure. The effect of the acoustic pillow liner on reducing the mid and high frequencies at the patient?s ears will be studied. Experimental verification of the noise reduction active cancellation will also be demonstrated in laboratory testing. The results will then be used to identify the key elements required for airworthiness testing for use in US Army MEDEVAC and CASEVAC operations.

Keywords:
Active Quiet Pillow, Active Noise Control, Pink Noise Reduction, Medevac And Casevac Operations, Finite Element Analysis

Phase II of this project will focus on developing, constructing and demonstrating the operation of an prototype Active Quiet Pillow for reducing interior noise in helicopter medical evacuation scenarios. The innovation is based on a strategic combination of active noise reduction (ANR) and passive treatment elements in a pillow style arrangement. Two performance objectives to be demonstrated include laboratory testing by attenuating a 106dB pink noise field to 80dBA at the patient’s ears and flight testing in a representative MEDEVAC helicopter with 15dBA attenuation. A sophisticated FE model of the active pillow and rotorcraft interior will be developed in conjunction with Genetic Algorithms to determine an optimal active pillow design for maximum performance. A prototype will be constructed and tested under laboratory protocols referenced to the ANSI S12.42-2010 standard and flight testing programs. Practical product design aspects related to the size, weight, power consumption and integration into the MEDEVAC rotorcraft interior will be developed and implemented. Human factors aspects such as the comfort of the active pillow, effect of speech intelligibility and signal recognition will be studied. The transition of the development work to a realistic product will also commence with our team partner UTRC/Sikorsky.