Improved path guidance of feed drive axes by means of an inertia-based momentum actuator at the machine table (IMPULS)

• Applicant: Professor Dr.-Ing. Alexander Verl
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 391879683

Feed drives in machine tools create relative paths between tool and workpiece by executing a programmed motion sequence. Typical requirements are to keep the given geometry within a given tolerance limit at constant path velocity. However, limited motor power and structural compliance of the machines require a limitation of acceleration and jerk. Profiles that include velocity steps therefore cannot be planned with constant path velocity. Within the first two funding periods, a hybrid approach to overcoming such limitations was investigated. An inertia-based actuator is attached to the feed axes and can transmit a defined impulse via mechanical impacts in order to accelerate the axes. This enables almost abrupt changes in drive velocity and simultaneously reduces structural excitation. During the two funding periods, the proof of function was first carried out on a single axis and then subsequently on two perpendicular axes and the achievable dynamics and the limits of the concept were investigated. In the course of the third funding period, the concept is to be further improved, the accuracy increased and the identified deficits addressed. Therefore, a variation of the contact conditions is planned, which will make the concept less dynamic than the previously investigated configuration, which is designed for maximum dynamics. By a controlled reduction of the dynamics of the concept, the other components in a ma-chine are less stressed, while at the same time the dynamics of the concept remains higher than what can be achieved with conventional drives. Furthermore, FE methods are to be used to develop a model with which a simulative estimation of the con-tact parameters is possible. This is necessary for configurations where the previous identification, which is carried out with a stationary base axis, is not possible. An ex-ample for this is a mechanical coupling in the drive system (e.g., in a screw drive), which can be damaged by an impact. The aim of the third funding period is therefore to bring the concept closer to a real application.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Armin Lechler