Modeling and Identification of Load-Dependent Properties for Electrically Preloaded Rack-and-Pinion Drives

Rack-and-pinion drives are preferred feed drives for long travel distances and heavy loads in large machine tools. One of the advantages compared to other feed drive systems is consistent stiffness regardless of travel length. A primary challenge with rack-and-pinion drives is the achievable accu-racy due to backlash. To compensate for backlash, electrically preloaded systems are commonly used in machine tools. In the case of electrical preload between two motors, the system is more complex to identify because the feed drive specific properties cannot be directly assigned to the respective drive train. To address this issue, this paper presents a novel method for modeling and identifying the load-dependent stiffness and damping of an electrically preloaded system. For this purpose, a mathematical modeling based on experimental data from a test bench with industrial components is presented to separate the drive train specific properties. This allows the system behavior to be modeled more accurately and used for control approaches.