wps/theme2

Theme 2 : Acoustic Simulation

WP 2.1 : Acoustic Modelling of Static and Deforming Sound Reflecting Structures

Objectives

Derive static directivity of sound emission and sound reception processes for the different bat species, using data from Themes 1 and 2.
Derive time-varying directivity of sound emission and sound reception processes.

Description of work

Acoustic simulation tools developed in previous projects, i.e. BEM based acoustic field simulation, will be applied to the plastic heads of WP 1.1 in order to characterise the sound field around the static 3D shape of bat pinnae and noseleaves.

Next, new acoustic simulation tools will be developed based on thetools already present to extend the ``time-invariant'' acoustic field calculations to situations where the boundary shape changes over time, i.e. deforming pinna and noseleaf shapes.

Finally, the results from the simulation will be analysed to find extracues useful for target detection/identification/localisation that might have been created by structural deformations in the reflecting surfaces.

Deliverables

D 2.1.1: Characterisation of time-varying directivity of sound emission and sound reception for the different bat species (M24)

WP 2.2 : Capture and Analysis of Bat Calls sorted by Task

Objectives

Capture bat calls as produced during each of the different behaviours of interest to this project, for all four species.
Identify how call parameters vary with task and behaviour.

Description of work

Collect data from all four species of interest executing thevarious behaviours of interest, both in the confines of the flight cage and free in the wild.

Analyse the measurement results to extract and characterise the callparameters of relevance to the project i.e., relative intensity, duration, interpulse interval, frequency content.

For Micronycteris microtis, this work also involves solving problems associated with collecting and analysing their very soft calls.

Deliverables

D2.2.1: Characterisation of call parameters and their variation with behaviour/task/phase for each bat species (M8, M13, M24, M30) delivered incrementally as they are produced
D2.2.2: Set of characterised calls from a telemike carried by Noctilio leporinus (M15).

WP 2.3 : Inverse Reconstruction of Bat Calls

Objectives

To infer the true bat call given the position of the bat and multi-microphone recordings of the emitted sound.
To validate the computation using telemike recordings obtained in WP2.2.

Description of work

To know the bat calls as produced by the bats, the various filteroperations these sounds have undergone between production and recording have to be inverted.

Multi-microphone recordings combined with the knowledge of theemission head-related transfer function, as computed from the known shape, will be used to invert the received spectra into an estimate of the emitted spectrum. For the larger Noctilio leporinus, this information will be validated against direct measurements of the vocalisations as obtained from a microphone attached to the head of the bat: deliverable 2.2.2.

Deliverables

D2.3.1: Set of reconstructed bat calls emitted in the course of the behaviours of interest. (M18 and iterating up to M30)

WP 2.4 : Dynamic Directivity Shaping

Objectives

Design a sonar system that allows control of the directivity of both the sound generation and the sound reception subsystem.
Build bat head reproductions instrumented with sonar emitters and receivers that have controllable directivity.

Description of work

First, an overview of available technologies will be made with the aimof finding the technology with the highest potential of realising the objective of a controllable directivity and spectral response equivalent to that implemented by the bat's deformable structures. The important design issues are: the extent to which the directivity can be changed as well as the variation speed constraints imposed by the used technology.

Next, an operational prototype of the receiver subsystem will bedeveloped and integrated in the bat head reproductions. Finally, based on the knowledge gained in developing the receiver subsystem, an operational prototype of the emitter subsystem will be developed and integrated in the bat head reproductions.

Deliverables

D2.4.1: Build a receiver with controllable directivity (M12)
D2.4.2: Build an emitter with controllable directivity (M24)

Created by: admin last modification: Monday 16 of February, 2009 [09:22:44 UTC] by admin

Useful links

A presentation of the main points of the project.

Related Projects

The CIRCE robot bat head

2002-2005: CIRCE (Chiroptera Inspired Robotic CEphaloid; IST-2001-35144) which reproduced, at a functional level, the echolocation system of bats by constructing a bionic bat head that was used to systematically investigate how the world is not just perceived but actively explored by bats. This bionic bat head is of similar size to a real bat head to reproduce the relevant physics and consist of an emission/reception system capable of generating/processing bat vocalisations in real-time, a multi-degree of freedom mechanical system to allow realistic pinnae movement.

2005-2010: CILIA (Customized Intelligent Life-inspired Arrays; IST-2005-016039), about sensory systems based on arrays of hairs. The project aims to identify the common principles underlying the widespread use in nature of arrays of mechanical sensory cells for the extraction of meaning under adverse conditions and to make those principles available for design of engineered systems.

Contact :	webmaster AT chiroping.org	Last update :	Monday 16 of February, 2009	© Copyright ChiRoPing Consortium 2009
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