Hysteretic delta modulator to prevent parameter drift in adaptive-based controllers

The realization of adaptive-based controllers in many industrial control applications may exhibit the parametric drift behavior acquiring the well known bursting phenomenon. In this work, an original and novel technique is proposed to eliminate this phenomenon. It is based on a modification of the discrete-time delta modulator into its continuous-time domain and then by adding hysteresis. To verify our proposed method, numerical simulations are conducted to the Van der Pol oscillator control regulation problem solved by using a predictive adaptive-based control technique, where a small output time-delay is added to evidence the bursting phenomenon. Moreover, the realization of our hysteric delta modulator does not alter the original adaptive parametric process, this is an important contribution with respect to the existent algorithms on this topic.