Increased bandwidth of feed drives of machine tools with improper inertia ratio

• Applicant: Dr.-Ing. Armin Lechler
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280448906

For modern machine tools, feed drive systems with low transmission ratio have always been used, in order to achieve a high rapid feed rate. However, the low transmission ratio leads to an improper inertia ratio between sled and servo motor, which has a negative effect on the controllability. In this proposed research project, a new control method will be developed for the feed drive system with improper inertia ratio. The objective is to increase the bandwidth of the position control loop. The new method synthesizes a weakly set motor speed controller with an additional sled speed control loop. The first mechanical natural vibration, which limits the bandwidth of the feed system in most cases, can be attenuated by the motor, which is governed by a weakly set controller. The outside superimposed sled speed control loop raises the phase and amplitude of the motor speed control loop in the frequency domain, so that the system can achieve a higher bandwidth without any extra sensor or actuator. The experimental measurements have been carried out within the pre-work to examine the functioning of this method.

• DFG Programme: Research Grants