ONLINE CONTROL OF MACHINE-TOOL VIBRATION DURING TURNING OPERATION

The paper describes a control system designed to improve the surface f inish during turning by reducing the vibration of the machine tool. Vi bration control is achieved by sensing the relative vibration between the tool and the work-piece, generating a force which tends to neutral ize the excitation. The control system consists of an optical sensor f or measuring the relative displacement between the tool and the work-p iece, and a tool actuator for the control action, the optical sensor b eing made from a bunch of bifurcated optical fibers, whilst the tool a ctuator is an electromagnetic device. The control system has been test ed experimentally during turning under various cutting conditions. The improvement in surface finish is verified by comparing two identical surfaces, one machined with and the other without the designed feedbac k- control device. Results indicate that the amplitude of vibration de creases by 33% whilst the resulting improvement in the surface finish is about 22%. The control device developed is quite simple and can be used in an industrial environment.