Precise Position Control of Machine Tool Feed Drives in the Presence of Load Perturbation

On machine tools, precise control of the position of the tool tip relative to the workpiece is required to follow the desired path where quality of producing parts is significantly dependent on dynamic performance. The design of such a controller that can perform with all plant uncertainties is a major challenge. It is therefore the aim of this paper to assess the performance of a new design methodology that may enhance the performance of machine tool feed drives. The controller in general has a form of P/PI/PID (Proportional/ Integral/Derivative) compensators that is easy to implement in
practice and does not require additional hardware. In addition to a simple structure, the design applies the principles of a phase margin approach to allow the self-tuning controller to automatically update the controller settings. This ability is required to optimise control when the position and the mass of the fixture and/or workpiece change. Effectiveness of the proposed methodology is demonstrated in Matlab simulation, where its performance found good enough for industrial application.