Valve nonlinearities are responsible for producing limit cycles in the loop and consequently decreasing plant performance. In the case of an integrating plant, once the loop oscillation is detected, the engineer should distinguish between stiction and backlash, but no method is available in the literature to address this class of problem. In this paper, it is proposed a data-driven method to di...

The presence of stiction in actuators is responsible for deterioration of performance in control loops: the possibility of automatic detection of this phenomenon from the analysis of recorded data is certainly very important and should be included in a monitoring system. In the paper it is shown that the application on plant data of a largely diffused technique (Horch, 1999), may not be able to...

Automated non-invasive diagnosis and localization of the root cause of oscillations in process plants is a widely held industry goal sought in order to stabilize product qualities and reduce equipment problems and energy costs. As stiction in control valves is one of the leading causes of oscillations in plant variables, detection and localization of valve stiction is a major part of any method...

Inherent nonlinearities like, deadband, stiction and hysteresis in control valves degenerate plant performance. Valve stiction standouts as a more widely recognized reason for poor execution in control loops. Measurement of valve stiction is essential to maintain scheduling. For industrial scenarios, loss of execution due to nonlinearity in control valves is an imperative issue that should be t...

This paper presents an investigation into the viability of a new route for the fabrication of titanium-based MEMS RF switches for harsh environment applications. Titanium’s intrinsic toughness and corrosion resistance suggest that it would be highly suitable for such applications and recently developed titanium micromachining technologies now make exploration of this potential possible. Two des...

For control applications involving small displacements and velocities, friction modeling and compensation can be very important. In particular, the phenomena of stiction and presliding displacement (motion during sticking) can play pivotal roles. In this paper, it is shown that existing single-state-variable friction models possess either stiction or presliding displacement. Next, those models ...

We start by presenting a short explanation of the micro actuator working principle. The main contribution of this paper is the characterization of the coefficient of stiction between two silicon nitride parts of a MEMS actuator. Having one flat contact surface while the other is composed of many relatively sharp circular bumps, has the advantage that the effective contact area is drastically re...

This paper treats limit cycles caused by friction. The goal has been to explain phenomena that have been observed experimentally in mechatronic systems. Experiments have shown that oscillations of qualitatively different types can be obtained simply by changing controller specifications. Stiction is important in some cases but not in others. Necessary conditions for limit cycle are given for th...

Selective stiction has been successfully applied to the batch fabrication of angular vertical comb actuators made of single-crystal silicon with self-aligned comb sets. The possible failure modes of the devices during the manufacturing process are studied, and a novel design of stiction plate and mechanical spring is also presented to suppress the failure modes. The fabrication process with uni...