A Model of the Dynamics of a Lathe Toolpost that Incorporates Active Vibration Suppression
Frankpitt, Bernard A.
A simple, linear, system model is presented for a lathe with a toolpost that incorporates active vibration suppression. The toolpost model is built from linear dynamic models of the component parts of the toolpost design: the actuator and drive circuitry, and the mechanical toolpost. The toolpost model is then combined with linear models for the lathe dynamics and cutting process to produce a model of the entire mechanical system. This model is used as the basis for a controller design that uses a measurement of the actuator current for a sensor signal, and the voltage applied to the actuator by the power amplifier as a control signal.<P>The controller design uses the Hdesign methodology. The performance criteria for the toolpost design are interpreted as measures on transfer functions associated with the system model, and predictions of the performance of the design are made on the basis of these measures. The conclusion drawn from this work is that with careful design, the active control of vibration in turning processes is a promising application for stack piezo-ceramic actuators.