Variable Structure Control of a Mass Spring Damper Subjected to a Unilateral Constraint: Application to Radio-Frequency MEMS Switches

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Amer L. Allafi ◽  
Premjeet Chahal ◽  
Ranjan Mukherjee ◽  
Hassan K. Khalil
Keyword(s):  
Feedback Control ◽  
Radio Frequency ◽  
Transient Response ◽  
Control Strategy ◽  
Rf Mems ◽  
Unilateral Constraint ◽  
Mems Switches ◽  
Short Period ◽  
Feedback Control Strategy ◽  
Mass Spring

A feedback control strategy is presented for improving the transient response of the ubiquitous mass-spring-damper (MSD) system; the closed-loop system has a small settling time with no overshoot for a step input. This type of response is ideal for MSD systems subjected to a unilateral constraint such as radio-frequency micro-electro-mechanical-system (RF MEMS) switches, which are required to close in a short period of time without bouncing. The control strategy switches the stiffness of the MSD between its nominal value and a negative value, resulting in a hybrid dynamical system. A phase portrait analysis of the hybrid system is carried out to establish the asymptotic stability property of the equilibrium and quantify the transient response. Simulation results are presented using parameter values of a real RF MEMS switch from the literature. As compared to open-loop strategies that are currently used, the proposed feedback control strategy promises to provide comparable switch-closing times with robust performance and eliminate bouncing.

A Control Strategy for Eliminating Bouncing in RF MEMS Switches

2016 ◽  
Author(s):  
Amer L. Allafi ◽  
Premjeet Chahal ◽  
Ranjan Mukherjee ◽  
Hassan K. Khalil
Keyword(s):  
Control Strategy ◽  
Rf Mems ◽  
Mems Switches ◽  
Setting Times ◽  
Impact Forces ◽  
Rf Mems Switches ◽  
Main Disadvantage ◽  
Small Rise ◽  
Feedback Control Strategy ◽  
The Impact

RF MEMS switches have many advantages over solid-state switches but their main disadvantage is poor reliability. The reliability problem stems from the impact forces generated at the time of closing of the switch and subsequent bouncing. This paper proposes a feedback control strategy to rapidly close the switch without bouncing. The stiffness of the system is switched between a positive value and a negative value to achieve small rise and setting times with no overshoot. Simulation results are presented to demonstrate the feasibility of the proposed control strategy.

scholarly journals An Optimal Feedback Control Strategy for Nonlinear, Distributed-Parameter Processes

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 758 ◽  
Author(s):  
Debaprasad Dutta ◽  
Simant Ranjan Upreti
Keyword(s):  
Feedback Control ◽  
Oil Recovery ◽  
Control Strategy ◽  
Moving Boundary ◽  
State Feedback Control ◽  
Optimal Feedback Control ◽  
Distributed Parameter ◽  
Optimal State ◽  
Non Linear ◽  
Feedback Control Strategy

In this work, an optimal state feedback control strategy is proposed for non-linear, distributed-parameter processes. For different values of a given parameter susceptible to upsets, the strategy involves off-line computation of a repository of optimal open-loop states and gains needed for the feedback adjustment of control. A gain is determined by minimizing the perturbation of the objective functional about the new optimal state and control corresponding to a process upset. When an upset is encountered in a running process, the repository is utilized to obtain the control adjustment required to steer the process to the new optimal state. The strategy is successfully applied to a highly non-linear, gas-based heavy oil recovery process controlled by the gas temperature with the state depending non-linearly on time and two spatial directions inside a moving boundary, and subject to pressure upsets. The results demonstrate that when the process has a pressure upset, the proposed strategy is able to determine control adjustments with negligible time delays and to navigate the process to the new optimal state.

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