A Novel Cylindricity Measurement Method for Large Workpiece Based on Improved Model and Algorithm

Cylindricity is a crucial factor to estimate the manufacturing quality of large rotary parts. However, existing measurement systems can hardly deal with the precise cylindricity measurement challenges posed by large dimensions and great weights. In this article, a novel measurement system along with an improved error separation model and efficient solution algorithm for large rotary parts is proposed. Concretely, the innovative research includes three parts. First, a precise cylindricity measurement system with large variable ranges is proposed. Different from traditional workpiece rotation means, a sensor rotation system for data acquisition is designed to be independent of the air-bearing platform for workpiece centering. This contributes to stable and precise measurement under high-load and field conditions. Second, a more sophisticated and accurate measurement model is established, and the model-based error separation method is presented, which enables more accurate separation of error sources, such as eccentricity, measuring line offset, and workpiece axis tilt. Finally, a differential evolution growth algorithm (DEG), which is able to balance global search ability and local information utilization, is put forward to improve the efficiency and accuracy of model fitting in the error separation process. The proposed measurement system, model, and algorithm are all verified by simulations and experiments.