Acceleration Feedback

Acceleration Feedback in the SV6000

DYNAMICS AND CONTROL

Chatter vibrations are one of the main factors limiting the productivity of roughing operations on large milling machines. Active dampers have proved their efficiency to increase chatter stability; however these techniques require the installation of a new actuator on the machine.

THE CHALLENGE

The main aim of the project is to increase chatter stability with active damping strategies using the machine tool feed drives directly. Indeed, for low frequency structural chatter, the machine drive bandwidth could be large enough to actively damp structural modes.

THE RESULT

An Open CNC has been created, which has been implemented on the SV6000 machine to enter the feedback from the accelerometer to the speed set point of the axis controller. Simple simulation models have been developed to understand the theoretical behaviour of this new feedback. Then experimental tests have been carried out of the SV6000 machine to measure the effect of the feedback in the Frequency Response Function and during machine movements.
The Open CNC is a good tool to perform the initial tests but an industrially applicable implementation is under study. To conclude, this project has shown that the concept of acceleration feedback using the machine drives can indeed increase chatter stability.