Threshold dynamics in time-delay systems: polynomial ${\hat{I}}^2$-control in a pressing process and connections to blow-up

Abstract

This paper addresses a press control problem in straightening machines with small time delays due to system communication. To handle this, we propose a generalized ${\hat{I}}^2$-control method, which replaces conventional linear velocity control with a polynomial of degree ${\hat{I}}^2\ge 1$. The resulting model is a delay differential equation (DDE), for which we derive basic properties through nondimensionalization and analysis. Numerical experiments suggest the existence of a threshold initial velocity separating overshoot and non-overshoot dynamics, which we formulate as a conjecture. Based on this, we design a control algorithm under velocity constraints and confirm its effectiveness. We also highlight a connection between threshold behavior and finite-time blow-up in DDEs. This study provides a practical control strategy and contributes new insights into threshold dynamics and blow-up phenomena in delay systems.

11 pages, 9 figures