Dynamic displacement sensing, system identification, and control of a speaker-based tendon vibrator via accelerometers

We develop a speaker-based tendon vibrator capable of applying vibrations with sustained amplitudes and desired time–frequency profiles to be used in inducing kinesthetic illusions. For modeling and control of the tendon vibrator, we propose and experimentally validate a method for real-time dynamic displacement sensing based on accelerometers. We tested the accuracy of displacement measurements by comparing the movements of the vibrator measured with differential accelerometers to those measured by a high resolution optical encoder. We completed frequency domain system identification of the vibrator and obtained a parametric transfer function model via displacements sensed by the encoder and by analog and digital integration. We show that within the frequency range of interest 20 –100 Hz, analog and digital integration methods were successful in capturing an accurate model of the vibrator. Under feedforward control, developed tendon vibrator is able to generate sustained 2-mm peak-to-peak vibrations throughout the frequency range of interest.