Abstract-The objective of this paper is to analyze the dynamics of heat flow in thermal structures working under constant temperature operation. This analysis is made using the tools of sliding mode controllers. The theory is developed considering that the thermal system can be described using diffusive representation. The experimental corroboration has been made with a prototype of a wind sensor for Mars atmosphere being controlled by a thermal sigma-delta modulator.This sensor structure allows to analyze experimentally the timevarying case since changes in wind conditions imply changes in the corresponding thermal models. The diffusive symbols of the experimental structures have been obtained from openloop measurements in which pseudo-random binary sequences of heat are injected in the sensor. With the proposed approach it is possible to predict heat flux transient waveforms in many applications.

The objective of this paper is to show how the structure of a thermal wind anemometer can be tuned to ensure a fast response when the sensor works in closed loop configuration (constant temperature operation). If the thermal filter associated to the sensor structure has only one significative time constant, the resulting system time response, working in closed loop, is enhanced beyond the natural limit imposed by its own thermal circuit. This effect is theoretically explained using the theory of sliding mode controllers. Experimental corroboration is presented by comparing the results obtained with two prototypes of a spherical wind sensor for Mars atmosphere. It will be shown that in case of having only one significant time constant, the time response in closed loop is much faster than the value associated with that time constant. It will be experimentally shown that this effect is lost when the thermal filter has more than one significant time constant. Diffusive representation is used to obtain arbitrary-order models of the thermal structures of the sensors.

The objective of this paper is to obtain time-varying models of the thermal dynamics of a 3D hot thin film anemometer for Mars atmosphere. To this effect, a proof of concept prototype of the REMS (Rover Environmental Monitoring Station) wind sensor on board the Curiosity rover has been used. The self and cross-heating effects of the thermal structures have been characterized from open-loop measurements using Diffusive Representation. These models have been proven to be suitable in the analysis of the thermal dynamics of the sensor under constant temperature operation employing the tools of Sliding Mode Controllers. This analysis allows to understand the long term heat diffusion processes in the whole structure and how they may affect the raw output signals.

Abstract-This paper introduces Diffusive Representation as a novel approach to characterize the dynamics of charge trapped in dielectric layers of microelectromechanical systems (MEMS). Diffusive Representation provides a computationally efficient method to achieve an arbitrary order state-space model of the charging dynamics. This approach is particularly well suited to analyze the dynamics of the dielectric charge under nontrivial controls, as in the case of sliding mode controllers. The diffusive symbol of the experimental structure has been obtained from open-loop measurements, in which Pseudo Random Binary Sequences (PRBS) are applied to the device. The obtained model exhibits good agreement with experimental data and also allows to model the behaviour of the charge dynamics under excitation with arbitrary binary signals.

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