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Modélisation, contrôle haptique et nouvelles réalisations de claviers musicaux

José Lozada 1, 2
2 LIS - Laboratoire Interfaces Sensorielles
DIASI - Département Intelligence Ambiante et Systèmes Interactifs : DRT/LIST/DIASI
Abstract : The traditional acoustic piano action mechanism is composed of many different parts of wood, wool felt, leather, metal, and steel-springs. These parts form a multi-degree-of freedom system that transmits energy from the player to the hammer. In return, the action mechanism generates a specific tactile rendering that is felt by the pianist during playing. The haptic feedback is essential for a precise control of timing and loudness.

The action mechanisms used in numerical pianos are much simpler and therefore provide a poor haptic feedback. In the last few years, many developments have been carried out by keyboard manufacturers in order to improve the feeling of touch of their products. Most of these systems are not actively controlled and are based on simplified models of the dynamical behaviour of traditional pianos. According to users, improvements are still required in terms of size, performance and realism of the device.

Active systems capable of reproducing the dynamics of traditional piano have been developed as laboratory prototypes and commercial products. They are based on simplified models or pre-recorded dynamics that do not satisfactorily match the dynamical behaviour of the traditional piano key. Moreover, the size of these systems often based on electromagnetic actuators is not suitable for an industrial keyboard implementation. The resistant force provided by the traditional piano action mechanism varies from 0.5 N (the minimum force that initiates key motion), to 15 N (at fortissimo nuance). Extensive measurements of the kinematics of a grand piano action mechanism indicate that the duration of the key motion varies from 20 to 250 ms depending on the nuance whereas the key velocity varies from 0.1 m.s−1 to 0.6 m.s−1.

The main objective of this research work is to develop a novel digital keyboard capable of reproducing the behaviour of a grand piano action mechanism. It is composed of two main parts. First, the dynamics of traditional piano is studied, then the design and the control of a novel haptic interface based on magneto-rheological fluids are presented.

The dynamic model of the traditional piano action mechanism presented in this thesis takes into account the six degrees of freedom of the system under the hypothesis of rigid bodies. It is completed by the contacts and rotational links elementary models. A set of experimental procedures is used to identify the parameters of the model. Finally, a numerical simulation using Matlab/Simulink is presented.

The modelling and the identification of an original operation mode for MR fluids is presented and used for the design of the haptic interface for musical keyboards. An analytical model of the interface key is built and used to develop the control law. The mechatronic model is numerically simulated and compared to the real behaviour of the interface. Finally a real time control loop coupled to a virtual model is used to command the interface (for instance the dynamical model of the traditional piano).
Complete list of metadatas

https://pastel.archives-ouvertes.fr/tel-00280538
Contributor : José Lozada <>
Submitted on : Monday, May 19, 2008 - 11:41:10 AM
Last modification on : Wednesday, October 14, 2020 - 4:02:30 AM
Long-term archiving on: : Friday, May 28, 2010 - 7:29:55 PM

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  • HAL Id : tel-00280538, version 1

Citation

José Lozada. Modélisation, contrôle haptique et nouvelles réalisations de claviers musicaux. Automatique / Robotique. Ecole Polytechnique X, 2007. Français. ⟨tel-00280538⟩

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