Zeljko Mrcarica

Distributed control based on distributed electronic circuits: application to vibration control ☆

Abstract This paper focuses on the design of distributed control related to distributed mechanical systems. The sensors and actuators are assumed to be numerous and periodically distributed. The problem addressed in this paper is: “Can we find a way to approximate an optimal control law with a distributed electronic circuit”. Solutions to this problem are proposed in the framework of vibration control using piezoelectric actuators and sensors.

Designing HV active clamps for HBM robustness

Electrical measurements, physical damage analysis, and device simulation have proved that the drain junction breakdown voltage is the determining failure criterion for our HV active clamps. Using this criterion, the HBM and TLP robustness of such clamps can be accurately predicted by circuit simulation without the need for test silicon.

Transient electro-thermal simulation of microsystems with space-continuous thermal models in an analogue behavioural simulator

Abstract In many microsystems (MEMS), thermal effects have significant importance and system-level electro-thermal simulation is needed to shorten the product development cycle and to increase system reliability. The possibilities for space-continuous simulation of electro-thermal problems using an analogue simulator and an analogue hardware description language are described. In comparison to commercial finite element simulators, the relative error of thermal simulation is

Hierarchical modelling of microsystems in an object-oriented hardware description language

Hardware description languages can be used for the description of models of micromechanical transducers. This enables simulation of microsystems, i.e. micromechanics with processing electronics. If such a language is object-oriented, a space-continuous micromechanical model can be described as a composition of previously defined submodels of mechanical structures. Inheritance properties of an object-oriented language make this hierarchical description very straightforward. For spatial discretization of models, we have used both finite difference and finite element methods.

Integrated simulator for MEMS using FEM implementation in AHDL and frontal solver for large sparse systems of equations

MEMS that exhibit strong coupling between electronics and mechanics need to be described and simulated in a united simulation environment, in order to achieve more flexibility from the description point of view, and to avoid convergence problems. Behavioral simulators and analogue hardware description languages enable modeling of MEMS. Even space- continuous mechanical problems can be described in the hardware description language. That description should and can be automated. Space-discretization commonly leads to very large system of equations. For solving such systems, mechanical FEM simulators usually exploit iterative algorithms that have very low memory demands. However, if the problem at hand contains electronics, as in the case of intelligent materials, iterative methods might be not applicable, since the convergence is not guaranteed anymore. In our behavioral simulator we have implemented a frontal solver, enabling solution of very large sparse matrices with modest main memory resources by storing only part of the matrix at the time. Thermal problems with more than 20000 nodes have been simulated.

Approximation of distributed control laws using distributed electronic devices for vibration control

In this work the control of vibration in an elastic plate, by piezoelectric transducers, is considered. The model of the plate is that presented in ]2]. An approximation of the optimal controller by a derivative partial operator is given. It is based on a development in series of the Riccati operator with respect to the reverse of the stiffness. Its implementation in term of distributed analog electronic circuits, is developed. Numerical simulations, obtained by the coupling of Finite Elements code and a circuit simulator, Alecsis, are presented. To improve the preceding result an iterative algorithm of approximation of the optimal controller, being able to be implemented by an electronic circuit, is developed. The algorithm is inspired by the approach of [4].

Describing space-continuous models of microelectromechanical devices for behavioural simulation

Modern behavioural simulators and their hardware description languages enable the description of time-continuous and time-discrete models. In this work, a modelling technique is developed for the description of space-continuous models, where partial differential equations are used. A hierarchical library of partial differential equations and boundary conditions for microelectromechanical device modelling is created. Mechanically complex devices have been modelled for system-level simulation using this technique.

Analogue behavioural simulator as a tool for coupled electro-thermal analysis of microsystems

In many microsystems, thermal effects have significant importance and electro-thermal simulation is necessary to shorten the product development cycle. The possibilities for space-continuous simulation of electrothermal problems by using an analogue simulator and an analogue hardware description language have been described. In comparison to commercial finite element simulators, the relative error of thermal simulation is less than 0.08% for three-dimensional static analyses. Transient thermal problems with coupled electronic components have been simulated.

Electro-thermal simulation of microsystems with mixed abstraction modelling☆

Abstract Electro-thermal coupling is only one aspect of numerous interactions between physical domains in microsystems. Different physical effects govern the functionality of microsystems and the system-level modelling using standard electro-thermal tools is not easy. In order to predict potential failures in microsystem designs and reduce the costs of prototyping, it is important to involve the simulation of electro-thermal effects at the system level, early in the design process. Also, it is necessary to conduct a final verification of the complete system with all governing subsystems. This paper considers different issues of electro-thermal modelling for microsystems and proposes analogue simulators with hardware description languages as a tool for the system-level modelling. With increasing system complexity, the mixed abstraction modelling is the only way to achieve an optimal blend of the accuracy and the speed.

Capacitive pressure sensor for quasi-static conditions followed by A/D conversion

The combination of a circuit and a logic simulation, as well as the simulation of microsystems requires a flexible tool. Alecsis2.1 is used to simulate such system throughout: all the way from input pressure to digital word that represents measured amount of pressure. Applied methodology begins from behavioral description, continues proceeding classic circuit simulation, and ends with event-driven logic simulation.