A numerical simulation method is developed to analyze the dynamic responses of electrostatic actuators, which are electromechanically-coupled systems. The developed method can be used to determine the dynamic responses of cantilever-type switches, which are an example of typical MEMS (Micro-Electro-Mechanical System) devices driven by an electrostatic force. We propose the approach that adopts a point charge to deal with electric field effects between electrodes. This approach may be considered as a lumped parameter model for the electrostatic interactions. An advantage of this model may be the easy incorporation of the electrostatic effects between electrodes into a multibody dynamics analysis algorithm. The resulting equations contain the variables for position, velocity, and electric charge to describe the motion of the masses and the charges on the electrodes in a system. By solving these equations simultaneously, the dynamic response of an electrostatically-driven system can be correctly simulated. In order to realize this approach, we implement the procedures into RecurDyn, the multibody dynamics software developed by the authors. The developed numerical simulation tool was evaluated by applying it to cantilever-type electrostatic switches in many different driving conditions. The results suggest that the developed tool may be useful for predicting behaviors of electrostatic actuators in testing as well as in design.

As sewage treatment facilities are classified as energy-consuming facilities and the need for energy-saving measures has emerged, the Ministry of Environment has established the Basic Plan for Energy Self-Reliance of Public Sewage Treatment Facilities to achieve 50% energy independence by 2030. Therefore, this study conducted an ICT-based self-diagnosis web application study for sewage treatment facilities that provided a simulator utilization plan to site operators of sewage treatment facilities and suggested measures for the results of self-diagnosis through the development of a removal rate-based sewage treatment self-diagnosis application. Using the Massflow3 simulator, the measures and validation of abnormal conditions for BOD, SS, TN, and TP were conducted, and a web-based self-diagnosis algorithm was implemented to enable the operator to easily control the process based on the simulation results.

A numerical simulation method is developed to analyze dynamic response of electrostatic actuator, which is electromechanical coupled system. The developed method is applied to find a dynamic response of a cantilever-type switch model, which is a basic component of electro-mechanical coupled system driven by electrostatic force. First, point charges model on conductor is proposed as a lumped parameter model of electrical part. Then, this model is easily incorporated into a multi-body dynamics analysis algorithm, the generalized recursive dynamics formula previously developed by our research group. The resulting motion of equation of a coupled overall system is formulated as a differential algebraic equation form including electrical and mechanical variables together and is simultaneously solved in every time step. To implement this approach into the useful dynamics analysis tool, we used multibody dynamics software (RecurDyn) based on the generalized recursive formula using relative coordinate. The developed numerical simulation tool is evaluated by applying to many different driving condition and switch configuration. The final analysis model will be added to RecurDyn as a basic module for dynamics analysis of electro-mechanical coupled system.