Stribeck Parameters Estimation of a Diaphragm Valve Using Quasi Newton Method

摘要

Diaphragm valves are extensively used in the process industry for flow control. The seal packing of these valves may present high friction, degenerating the performance of the control loop. When it is not possible to correct the friction increase with a physical maintenance of the valve, some friction compensation techniques may be used to mitigate its effects. Essentially, to design the compensator, one needs to quantify the system friction based on a given model. The Stribeck curve defines the friction–velocity relationship of a mechanical system, which is of utmost importance when designing friction compensation laws. In this work, the parameters of the Stribeck curve of a real diaphragm valve were estimated using a second order gradient method (quasi Newton). The results are satisfactory when some cautious measures are taken into account when implementing the optimization algorithm.