Implementation of a haptic musical instrument using multi-signal fusion for force sensing without additional force sensors

摘要

This paper describes the implementation of a haptic system for simulating the force-feedback of a centuries-old musical instrument, the carillon. A carillonneur's performance depends on a developing familiarity with force-feedback associated with a particular instrument. Force-feedback may vary not only across the range of the instrument but from one instrument to another. However, carillonneurs have restricted access to their instrument for rehearsal, unlike musicians who specialise in other instruments. At best, rehearsal times on the actual instrument are shared with other carillonneurs; at worst, a carilloneur rehearses mainly on a practice instrument that does not prepare them for the force-feedback and sonic characteristics of the actual instrument. A haptic device that simulates the force-feedback of a carillon must meet exacting requirements associated with musical performance and musical skill acquisition. Our haptic device uses a voice-coil linear actuator in a position-control loop where the force applied by a carillonneur is measured by analysing the noisy current produced from an analog servo controller reacting to position error. A parametised model of the servo is determined using system identification methods and forms the basis of a Kalman filter for the servo current signal, closing an admittance display loop around carillonneur-applied forces and the mechanical action of the instrument simulated in a virtual environment. This generalised method is particularly applicable to scenarios common in creative applications where hardware is ‘handed-down’ from other projects.