Compensation of dynamic vibrations and spindle-runout

A primary intention with regard to chip-cutting surface processing of work pieces is to improve the finished surface quality of the work pieces. New approaches are needed to meet the increasingly stringent demands placed on machine tool manufacturers for cost-aware improvement of the machine systems. Conventionally, machine vibrations are minimized by constructional optimization. This can entail high production costs. With the increased availability of electronic systems and, above all, considering the cost advantage of electronic control compared with mechanical construction optimization, active compensation of relative motion between tool and work piece caused by machine vibration has become an attractive approach to solve the problem. This can be achieved with a position-correcting device, the so-called actuator, on the tool to guide the latter such that the relative distance between the tool and the work piece always corresponds as exactly as possible to the setpoint specifications . Disturbance measurement and calculation of the compensating signal as well as the positioning correction itself require a length of time which is not negligible compared with the period duration of a typical machine vibration. Therefore a predictive projection of the disturbance waveform into the future is required, by the total time taken for measurement, calculation and position correction.