High performance and high precision ultrasonic motor-actuated positioning servo drive system using improved fuzzy-reasoning controller

This paper presents the latest significant developments of ultrasonic motor (USM)-actuated servo drives suitable for direct-drive motion systems, which effectively introduce the practical fuzzy-reasoning controller with speed and positional state-variable feedback schemes. The USM-actuated servo control system is schematically composed of the commercially-available travelling-wave type USM, mechanical loads, high-frequency DC-DC chopper regulator, two-phase high-frequency resonant inverter using parasitic piezo-electric load resonance parameters, pulse-encoder and its processing interface, and newly-developed fuzzy-reasoning software controller. The experimental breadboard is feasibly implemented and the software of the fuzzy-reasoning controller is designed for the specific USM characteristics and USM-related control loops. The experimental verifications are illustrated and their results are evaluated using a one-axis servo motion drive system from a practical point of view. It is proved that a new compact servo motion drive system using USM which incorporates the microprocessor-based two-input and one-output fuzzy-reasoning controller is cost-effective and more acceptable for certain direct drive applications.>