Machine Control System Modeling and Design For Incremental Profile Forming of Metal Tubular Structures
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Date
2019-05
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The Ohio State University
Abstract
Today, manufacturers require specialized machinery to produce various metal tubular designs for aeronautical and automotive applications. In an effort to reduce machine and tooling redesign with every unique tubular cross-sectional profile, the Incremental Profile Forming (IPF) process was created a few years ago at the Technical University of Dortmund, Germany. The innovative IPF machine includes eight degrees of freedom of motion which enable flexibility in manufacturing, such that a single machine can produce various metal tube profiles. However, control of machine motions alone has not resulted in precision of the manufactured part geometry. The lack of precision using the current process calls for extending control of the manufacturing process beyond machine control, and for better utilization of machine control to support such extension. The purpose of this research is to investigate current control of machine motions used by the IPF machine, and identify ways to integrate machine control with process control to increase precision of the manufactured parts.
Within this research, the current machine control systems used to govern the motions of the radial actuators used for tube forming were studied. Multiple experiments were conducted on the IPF machine to help validate system models and investigate system responses to various inputs and IPF processes. The gathered force, position, and structural measurements were analyzed to support the development of the motion control system models, as well as active stiffness control and online identification methods. Extensions of the machine control to include active stiffness control and online-identification of process parameters are two different control methods that were investigated to help improve precision in tube manufacture. The potential of these two methods to better accommodate various process disturbances and process characteristics was examined.
Research results include complete models of the commercially available motors and radial actuators that are used by the motion control systems. These models were used to modify active stiffness control and online identification capabilities. This work establishes the basis for, and feasibility of, controller modeling for current and potential future functions performed by the IPF machine. Successful integration of new control methods in the IPF machine will enable effective use of its flexibility, while improving its accuracy in metal tube manufacturing.