Optimizing the Active Speed Control Unit for In-Line Inspection Tools in Gas

The simulation and optimization of an active speed control unit for an intelligent in-line inspection tool is presented. A simple model was developed describing the dynamics of such a tool in a gas pipeline. The dynamics are represented by a set of coupled differential equations incorporating tool velocity, pressure, differential pressure over the tool and bypass area. These equations were solved numerically by implementation in a simulation environment. Control rules for an active speed control unit were integrated in this model to simulate the effect of regulation activities on the reactions of the tool. The rules were chosen to represent the capabilities of a real unit (electronics and mechanics). The results of the simulation are compared with the behavior of a tool in a 40” gas pipeline and the regulation algorithm is optimized with respect to the capabilities of the existing control unit.