Tool Positioning for Noncircular Cutting with Lathe

This paper presents the design and implementation of a digital controller for a lathe to machine workpieces vith noncircular crossections. Noncircular cutting is accomplished by controlling the radial tool position in the direction normal to the surface of workpiece. A discrete time model for the tool carriage in the radial direction is obtained by a least squares method applied to input and output data. The model is used for designing digital feedback and feedforward controllers. The zero phase error tracking control algorithm is applied as a feedforwad control law for precise positioning of the tool. The effectiveness of the proposed controller is evaluated by experiment and simulation.