Search

Introduction:MiniPINS is an ESA study to develop and prototype miniaturised surface sensor packages (SSPs) for Mars and the Moon. The study aims at miniaturising the scientific sensors and subsystems, as well as identifying and utilizing commonalities between Mars and Moon SSPs, allowing to optimise the design, cut costs and reduce the development time.Mars In-Situ Sensors (MINS) is a penetrator with approx. 25 kg mass, piggy-backed by another Mars mission spacecraft to Mars. In total 4 identical penetrators are deployed to different landing sites either from the approach orbit or Mars orbit. The design of MINS has significant heritage from FMI’s MetNet mission design[1]. The entry, descent and landing sequence of MINS is completely autonomous and controlled by its on-board computer. In the Martian atmosphere the penetrators undergo aerodynamic braking with inflatable breaking units until they reach the target velocity of 60-80 m/s for entering the Martian surface. The nominal mission duration is one Martian year.Lunar In-Situ Sensors (LINS) is a miniature 7 kg station deployed on the Moon surface by a rover. LINS mission consist of 4 surface stations deployed to different sites within the rover’s traveling perimeter. The LINS scientific package consists of several scientific instruments to study the Moon for 2 years. Mars SSP sensors:MINS will study the Martian atmosphere, seismology and chemistry. The MINS payload consists of a camera, a visual spectrometer, a meteorological package, an impact accelerometer, soil thermoprobes, a chemistry probe, a seismometer and a radiation monitor. Many of the instruments have Mars heritage but additional qualification is required due to landing shock. The meteorological package consists of air temperature sensors, pressure sensor, relative humidity sensor, wins sensors, dust sensor and solar irradiance sensor. Pressure and humidity sensors are provided by FMI and the sensors have heritage from multiple Mars missions like the M2020 Perseverance rover[2]. Air temperature sensors are provided by CAB and they have heritage from MSL[3], InSight[4] and M2020[2]. Solar irradiance sensor (SIS)[5] is provided by INTA and the technology has been used in several Mars missions[6]. The selected design for MiniPINS is the SIS for ExoMars ‘22. Also based on ExoMars ‘22 METEO is the dust sensor by UC3M. The chemistry probe is a new design developed by CAB. It is composed of several miniature sensing needles that share an acquisition electronics to measure pH, salinity, water content, conductivity and temperature of the Martian regolith. The current TRL is 6. The thermoprobe is also a new design developed by UPC for characterizing the thermophysical properties of the regolith.The visual spectrometer selected for MiniPINS is based on tunable Fabry-Pérot interferometer (FPI) technology by VTT Technical Research Centre of Finland[7]. The piezo-actuated FPI technology has previously flown on board nanosatellites Aalto-1, Reaktor Hello World and PICASSO demonstrating operation in different wave lengths. Due to its maturity and flight-proven performance, the near-IR concept is the baseline for the MINS spectrometer.Moon SSP sensors:LINS proposal is focused on two principal science objectives: understanding the structure and composition of the lunar interior and the characterization of the lunar surface environment in view of human exploration and resource extraction. The placement of a network of short period seismic stations will allow determining the thickness of the lunar crust (upper and lower) and its lateral variability. Due to smaller size the LINS has fever scientific sensors and many are common with the MINS packages. Magnetometer selected for LINS is based on the triaxial magnetometer developed by INTA for MetNet Mars mission. The sensor will require some modifications and adaptation of the ejection mechanism as well as temperature qualification for Lunar conditions.Shared sensors:The cameras of both MINS and LINS are based on the Athermalized Panchromatic Imaging System (APIS) low-resolution refractive camera used by INTA as a CubeSat payload which flew on-board the OPTOS satellite. It is based on a 1.3 MP CMOS image sensor from Cypress Semiconductor Corporation but the optics will be redesigned taking into account the applicable requirements for each mission. Miniature wind sensors (Mars) and thermoprobes are based on the same sensor structure developed by UPC. The new type of sensor is a spherical shell divided into four sectors. To sense temperature and provide heating power, a customized 3 x 3 mm silicon die, including a platinum resistor, is attached to the inner side of each sector. In MINS the wind sensors are located in the deployable mast and the soil sensor is in a compartment below the surface in contact with the regolith. For LINS a dedicated deployment mechanism must be developed for the soil probe. The wind sensors and soil probes are currently in TRL 6.The short period seismometer is based on a miniature MEMS resonator by Imperial College, previously used in InSight[8]. For LINS a variant of the sensor, called the Silicon Seismic Package, (SSP)[9] is proposed.The impact accelerometer of MINS will be a new development. To miniaturise the accelerometer, a commercial part from PCB Piezotronics has been selected as the basis of the sensor and the complete sensor assembly will be developed and qualified by INTA. Lunar SSP also includes an accelerometer which is used to determine the attitude of LINS. It is based on an Analog Devices component ADXL327BCPZ, already qualified by INTA for Mars, but LINS missions requires even larger temperature range so additional qualification is foreseen.The radiation monitors included in both missions are based in the Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) dosimeters. Proposed provider of MOSFET dosimeters is Tyndall National Institute.Project status:The MiniPINS study, consisting of project phases A and B1, is nearly completed and a final review was held in autumn 2021. As a follow-up, the European Space Agency is facilitating an industrial development of European inflatable deceleration system.

Perseverance's Mars Environmental Dynamics Analyzer (MEDA) is collecting data at Jezero Crater, characterizing the physical processes in the lowest layer of the atmosphere as no previous instrument did before. Here we show that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable nighttime thermal inversion to a diurnal, highly turbulent convective regime, with large vertical thermal gradients, and where local surface properties (such as Thermal Inertia) play an essential role. Recording multiple daily optical depths yielded higher aerosol concentrations in the morning than in the afternoon. Measured wind patterns are mainly driven by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations raise new puzzles in which changes in surface albedo and thermal inertia may play an influential role. On a larger scale, surface pressure shows typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle characterized before as low wave activity. These observations, combined and simultaneous, show the rich Jezero’s meteorology, and unveil the diversity of processes driving change on today’s Martian surface.

In this work, a novel mixture of ionic liquid gel polymer electrolyte (ILGPE), containing 1-butyl-3-methylimidazolium bromide, ammonium acetate and poly(vinyl alcohol), with Si@C and SiO2 embedded nanoparticles is fabricated. The resulting CILGPE is deposited onto interdigitated electrodes. The fabricated electrolytes have been characterised by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and the resulting capacitors have been characterised by impedance spectroscopy (IS) and linear sweep voltammetry (LSV) and modelled. The specific capacitance for capacitor with ILGPE is 0.042Fcm−3, while for the capacitor with SiO2 and Si@C embedded in ILGPE are 0.072 Fcm−3 and 0.06 Fcm−3, respectively. Therefore, the addition of SiO2 and Si@C nanoparticles improves the capacitance by 71% and 42%, respectively. The results of fitting I-V curves exhibit reductions in both the activation voltage (Vtr) and in the voltage that indicates the traps are filled (VTFL) with the addition of nanoparticles, revealing an increase in charge contribution. We propose that the capacitance enhancement is due to the contribution of nanoparticles to: (i) the creation new effective ion transport pathways, (ii) ion dissociation in the electrolyte and (iii) the crystallinity reduction of ILGPE. This work contributes with new findings about the effect of nanoparticles on the Space-charge-limited-conduction (SCLC) mechanism and how these changes in transport mechanism are related to the series and leakage resistances, capacitance, and physicochemical properties.

MiniPINS (Miniature Planetary IN-situ Sensors) is an ESA study led by the Finnish Meteorological Institute to develop and prototype miniaturised surface sensor packages for Mars and the Moon. The study aims at miniaturising the scientific sensors and subsystems, as well as identifying and utilizing commonalities of the packages, allowing to optimise the design, cut costs and reduce the development time. This presentation includes the main results from Phase A study and Preliminary Requirements Review of MiniPINS.Mars In-Situ Sensors (MINS) is a concept based on the strong heritage of the MetNet lander. MINS mission consists of 4 scientific observation posts on the Martian surface, about 25 kg each. The MINS landers will travel to Mars aboard the carrier spacecraft provided by another mission. Several concepts for MINS penetrators were studied in Phase 0, and finally 2 concepts were chosen for the final selection. The concept selection was driven by the target penetration depth, as this parameter is deeply influenced by the penetrator design. The MINS concept of 0.5 m penetration depth was selected by means of a trade-off. The selected concept is a rigid probe concept, similar to MetNet penetrator. Its development level is quite high, and its scope is compatible with MINS mission. This concept is limited from the scientific point of view, as it does not allow to penetrate so far in Martian subsoil; but its more advantageous from the criticality point of view as it has a higher development level and is less complex. The concept allows to perform majority of the scientific measurements, as all science goals except the heat flow measurement, can be accomplished also in shallow depth. Lunar In-Situ Sensors (LINS) is a new concept of a scientific mission package to investigate the Lunar surface and environment. LINS missions consist of 4 surface stations, 7 kg each, deployed on the Moon by a rover. In the case of LINS thermal and power design are the major drivers of the LINS architecture definition because of the Moon extreme environment, owed in part to the long lunar night period. The most relevant decision with regard to the LINS package is whether to include a RHU or not. In the absence of an RHU, the thermal and power subsystems become strongly compromised. Incorporation of an RHU offers many advantages. Consequently, the incorporation of the RHU is the selected concept for LINS. The two main concepts for mechanical structure of the LINS were evaluated: monocoque structure with legs and double structure without legs. A design concept was chosen that consists of a double structure, so that there is an internal and an external one. The external one acts as an exoskeleton for the internal and is separated from it by blocks. The separation between the two structures provides some space to accommodate additional thermal insulation if necessary. AcknowledgementsThe MiniPINS (Miniaturized Sensor Packages and Delivery Systems for In-situ Exploration) Contract is carried out and funded by the European Space Agency activity no. 1000025265 in the “ESA-Star” System.

The phenomena related to charge trapping are among the most relevant open issues that affect the long-term stability of perovskite-based devices. According to this, the objective of this paper is to report experimental results in which a charge control strategy is used for the first time in a solar cell structure that has a high trap density perovskite absorber. This device has also noticeable J-V hysteresis, produced by non-capacitive effects. The control strategy proposed, based on sigma-delta modulation, applies to the device an appropriate sequence of voltage waveforms determined after periodical current measurements made at a constant voltage. The experimental results obtained and the fittings made with a phenomenological model indicate that this approach allows controlling several charge-related effects. As a consequence, the J-V characteristic of the device is successfully shifted and stabilized to predetermined positions. This research was funded by the Spanish Ministry MINECO (under grant RTI2018-098728- B-C33), the Severo Ochoa program (under grant SEV-2015-0522), MINECO and FEDER (under grant MAT2017-89522-R), the Fundacio Privada Cellex and the CERCA program from the Generalitat de Catalunya.

The objective of this work is to present the first analytical and experimental results obtained with a 3D heat flux sensor for planetary regolith. The proposed structure, a sphere divided in four sectors, is sensible to heat flow magnitude and angle. Each sector includes a platinum resistor that is used both to sense its temperature and provide heating power. By operating the sectors at constant temperature, the sensor gives a response that is proportional to the heat flux vector in the regolith. The response of the sensor is therefore independent of the thermal conductivity of the regolith. A complete analytical solution of the response of the sensor is presented. The sensor may be used to provide information on the instantaneous local thermal environment surrounding a lander in planetary exploration or in small bodies like asteroids. To the best knowledge of the authors, this is the first sensor capable of measuring local 3D heat flux This work was supported in part by the Spanish Ministerio de Economía y Competividad under Projects RTI2018-098728-B-C31 and RTI2018-098728-B-C33

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ One way to optimize the operation of chemical systems consists on using closed loop controls while the system is operated. This way, it is possible to optimize the operating point in the plant, process or chemical system so that certain quantities are maximized/minimized or time responses are reduced. In the design of the closed loop controls, though, one of the problems is the large number of configuration parameters involved and the uncertainties in the system. The objective of this paper is to present how recently proposed controls, exploiting time-scale separation, allow to configure their closed loop configuration parameters from open-loop measurements. These controls have been proposed to accelerate the time response of metal-oxide gas sensors by operating at constant surface potential. The main result of the paper explains the link between the open loop measurements and closed loop operation. Experiments are provided using a commercial off-the-shelf Microelectromechanical gas sensor. The work of M. Dominguez-Pumar, L. Kowalski and V. Jimenez was partially supported by the Government of Spain through the Agencia Estatal de Investigación Projects ESP2016-79612-C3-2-R and RTI2018-098728-B-C33 and by the Generalitat de Catalunya through the Project 2017 SGR 279. The work of J.M. Olm was partially supported by the Government of Spain through the Agencia Estatal de Investigación Project DPI2017-85404-P and by the Generalitat de Catalunya through the Project 2017 SGR 872.

The objective of this paper is to explore the capability of a charge trapping control loop to continuously compensate charge induced by ionizing radiation in the dielectric of metal–oxide–semiconductor (MOS) capacitors. To this effect, two devices made with silicon oxide have been simultaneously irradiated with gamma radiation: one with constant voltage bias and the other working under a dielectric charge control. The experiment shows substantial charge trapping in the uncontrolled device, whereas, at the same time, the control loop is able to compensate the charge induced by gamma radiation in the second device.

This work investigates, analytically and experimentally, the effects induced by the use of a first-order sigma-delta (ΣΔ) feedback loop as a control method of dielectric charging for capacitive microelectromechanical systems (MEMS). This technique allows setting of a desired level of net charge in the dielectric of a MEMS device by continuously alternating the polarity of the actuation voltage. This control system displays a number of interesting effects, inherited from ΣΔ modulation and not usually found in conventional MEMS applications, with the charge-locking phenomenon being the most relevant. The convergence time and the effectiveness of the control method are also investigated and discussed.

This paper analyzes the behavior of a miniature 3D wind sensor designed for Mars atmosphere. The sensor is a spherical structure of 10 mm diameter divided in four sectors. By setting all the sectors to constant temperature, above that of the air, the 3D wind velocity vector can be measured. Two sets of experiments have been performed. First, an experimental campaign made under typical Mars conditions at the Aarhus Wind Tunnel Simulator is presented. The results demonstrate that both wind speed and angle can be efficiently measured, using a simple inverse algorithm. The effect of sudden wind changes is also analyzed and fast response times in the range of 0.7 s are obtained. The second set of experiments is focused on analyzing the performance of the sensor under extreme Martian wind conditions, reaching and going beyond the Dust Devil scale. To this purpose, both high-fidelity numerical simulations of fluid dynamics and heat transfer and experiments with the sensor have been performed. The results of the experiments, made for winds in the Reynolds number 1000&ndash, 2000 range, which represent 65&ndash, 130 m/s of wind speed under typical Mars conditions, further confirm the simulation predictions and show that it will be possible to successfully measure wind speed and direction even under these extreme regimes.

Hypothesis The electrowetting on dielectric or EWOD phenomenon is used in a wide range of applications, such as Liquid Lenses, Lab-on-Chip devices, or EWOD displays, among others. Its chemical resistance, electrical stability, ease of application, and low cost make polytetrafluoroethylene (PTFE) the preferred hydrophobic dielectric layer for such applications. However, the hydrophobic behaviour represents a challenge for spin coating other layers over its surface. As a consequence, several techniques are implemented to modify the surface of PTFE. These methods are complex, time-consuming, and produce morphology changes over the surface that are difficult and sometimes impossible to recover. In this work, we propose a new surface modification method that is based on a non-coherent UV light exposition method and a specific water treatment, that lead to a change from hydrophobic to hydrophilic, and a perfect recovery from hydrophilic to hydrophobic behaviour. Experiments In this work, the fabrication of the hydrophobic layer treatment starts with the creation of a thin layer of alumina ( A l 2 O 3 ) over a glass substrate using an atomic layer deposition technique (ALD). A mixture of 10:1 FC40 solvent and Teflon Dupont AF1600 was coated over the alumina layer. The Teflon film was exposed to UV light produced by a low-pressure mercury (Hg) lamp for a period that ranges from 3−6 min. The results were analysed by scanning electron microscopy, x-ray spectroscopy, and static deionized water contact angle measurements. Findings Contact angles dependent on UV light exposure time were observed. From the scanning electron microscopy analysis, it was confirmed that the UV treatment does not produce morphology changes over the surface. Nevertheless, the x-ray spectroscopy revealed that the UV exposed samples react when they are brought into contact with deionized water, improving the adhesion of the surface. The original hydrophobic behaviour of the surface is recovered (up to 98 %) after 3 h of thermal treatment. Furthermore, the thermal recovery analysis reveals a correlation between the recovery percentage and the applied temperature.

We introduce the first control of surface potential (SP) in MOX gas sensors using UV light (367 nm). The control is based on sigma-delta modulation implementing a sliding mode control on the surface potential of the sensor. Measurements are presented using a sensor made of WO 3 nanowires under mild heating at 125 oC. Without control, the sensor shows no response to ethanol. Under control, the detection limit is beyond 2 ppm with a response time below 5 minutes. For NO 2 , the response time is reduced by a factor of 10. By operating the sensor at constant SP it is possible to improve both dynamics and sensitivity. This new methodology applies generally to a wide range of gas sensitive materials and transducing elements.

© . This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ The objective of this paper is to present a charge trapping control method for MIM capacitors in whichthe dielectric is made of electrospray-deposited silica nanoparticles. The influence of the bias voltage onthe impedance spectra of the devices is analyzed, as well as the main conduction mechanisms along thestructure. The control method allows to monitor and control the long term drifts in the impedance ofthese devices, which are a result of the applied bias voltages. This work was supported by the Spanish Ministry MINECO un-der project RTI2018-098728-B-C33, by the European Space Agencyunder project ESA AO/1e8876/17/NL/CRS and by SENESCYT of therepublic of Ecuador under agreement 2016-AR5G8871

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The objective of this paper is to introduce a modeling strategy to characterize the dynamics of the charge trapped in the dielectric of MOS capacitors, using Diffusive Representation. Experimental corroboration is presented with MOS capacitors made of Alumina in three different scenarios. First, the model predictions are compared with the trapped charge evolution due to arbitrary voltage excitation. Second, the predictions are compared with the measurements of a device in which a sigma-delta control of trapped charge is implemented. Finally, the time evolution when the device is simultaneously controlled and irradiated with X-rays is compared with the predictions. In all cases, a good matching between the models and the measurements is obtained.

This work presents a double sliding mode control designed for accelerating the measurement of heat fluxes using thermopiles. The slow transient response generated in the thermopile, when it is placed in contact with the surface to be measured, is due to the changes in the temperature distributions that this operation triggers. It is shown that under some conditions the proposed controls keep the temperature distribution of the whole system constant and that changes in the heat flux at the thermopile are almost instantaneously compensated by the controls. One-dimensional simulations and experimental results using a commercial thermopile, showing the goodness of the proposed approach, are presented. A first rigorous analysis of the control using the Sliding Mode Control and Diffusive Representation theories is also made.

Direct numerical simulation and large-eddy simulation have been performed for a heated sphere at Reynolds numbers of R e = 1000 and R e = 10 4 , respectively. The Prandtl number for both simulations has been P r = 0.7 . Measurements of the local and average Nusselt number are performed and compared with literature available experimental results. Average and front stagnation point Nusselt numbers increase with the Reynolds number, while the minimum value moves towards the sphere apex as the flow enters the sub-critical regime. Differences in both viscous and thermal boundary layers are observed, while the shape factor at Reynolds number R e = 10 4 behaves similarly to that observed in circular cylinders at comparable Reynolds numbers. It is shown that as the Reynolds number increases, the increase in turbulent kinetic energy promotes the entrainment of irrotational flow thus enhancing the temperature mixing in the zone. The near wake, between 5 ≤ x/D ≤ 15, spreads at a faster rate at R e = 1000 with a slope close to x/D1/2, while at R e = 10 4 it follows a trend close to x/D1/3.

This paper presents a characterization method based on diffusive representation for a class of linear or nonlinear time-varying diffusive systems. The system variation with time may come as a result of the own actuation over the device or as a result of an external disturbance. Experimental results for both cases are presented. This method has been tested on a prototype of the REMS thermal wind anemometer for Mars atmosphere in which the time variation is induced by wind changes in a wind tunnel. The same method is also applied to model the nonlinear charge trapping dynamics of a contactless MEMS capacitor, in which the system variation with time comes from the nonlinear dependence on the applied voltages. In both cases, the obtained state-space models are able to reproduce and predict the behavior of the devices under arbitrary excitations.

The purpose of this paper is to show that the charge induced by radiation in a dielectric on which a sigma–delta control of dielectric charge is implemented, can be seen as a disturbance in a sliding mode controller. Preliminary experimental results are presented in which a MEMS device is irradiated with X-rays, while the dielectric charge control is continuously being monitored. The charge induced by radiation generates a change in the control bitstream, which is associated with the presence of an external disturbance on the governing control equations.

Gas sensing is nowadays a key actor in pollution observation and detection of chemical toxic agents or explosives. All these applications require the shortest possible time response. Very recently, a control of the surface potential in gas sensors based on metal oxides has experimentally shown to dramatically improve the time response of metal-oxide gas sensors. The proposed control is inspired in sigma-delta modulators. This paper aims at studying the resulting dynamics in the sensor from a theoretical point of view. Using state space models, it is shown how the state variables, namely the concentrations of ionized species in the sensing layer, evolve with time in open and closed loop configuration. This analysis studies how it is possible to alter the dynamics of the overall system, while at the same time keeping some important characteristics of sigma-delta modulators, such as quantization noise-shaping. Numerical simulations validate the obtained results.

Here we review recent results on the synthesis of single-crystalline metal oxide nanomaterials and their integration in resistive gas sensing devices. Emphasis is put on the integration of such nanomaterials in a wide spectrum of transducing platforms, ranging from standard ceramic to silicon MEMS or flexible polymeric. Some strategies for achieving higher selectivity are discussed, which are followed by a discussion on the development of advanced operation techniques for achieving more stable and faster response to gases. Finally, some aspects that remain open for research are identified

In this work the effect of the dielectrophoretic force (DEP) in the self-assembly process of nanoparticles electrosprayed onto a substrate, is examined. DEP force is originated by the electric field created by the electrospray gun and by the distortion of the field created by the effective dipole of each nanoparticle. It is also shown that the modulus of this force is large when the distance between particles is few times its diameter, provided the medium is wet and the electric field is not switched off. The directional nature of DEP In this wet phase, is shown to chain nanoparticles aligned with the main electric field direction. Although there is a repulsive force between chains in the orthogonal direction to the field, it is minimum when the beads align with the voids in the nearby chains. DEP is a dominant force in the close distances of nanoparticles compared to double layer, van der Waals, electrophoretic retardation, weight and buoyancy.

The objective of the paper is to present the implementation of the first sigma-delta control of Surface Potential (SP) for nanostructured layers made of metal oxides in gas sensors. The objective of this type of controls is to improve the time response and reliability of these sensors. This is done by generating adequate temperature waveforms aiming at generating a constant surface potential in the nanostructures. By enforcing the condition constant SP the dynamics of all state variables is altered.

This paper presents a new method to characterize the dynamics of the charge trapped in the dielectric layer of contactless microelectromechanical systems. For sampled-time systems, this allows knowing the state of the net charge at each sampling time without distorting the measurement. This approach allows one to model the expected behaviour of dielectric charging as a response to a sigma-delta control of charge. The goodness of the proposed approach is obtained by matching the experimentally obtained closed loop response with the one predicted using the proposed characterization method. The characterization method also provides a criterion to avoid nonlinear effects, such as fractal-like behaviour, in charge control.

In this paper, we present a new closed-loop control method of dielectric charge for contactless capacitive microelectromechanical systems. The method uses a feedback loop to maintain the net charge in the dielectric layer at the desired level. We show that, under particular conditions, the control loop is similar to a thermal sigma-delta modulator as used in thermal sensors. In this way, the control actuation will inject an average charge into the dielectric to keep it at a desired level while applying an actuation bit stream to compensate the charge being continuously leaked out of the dielectric. The validation of the method is carried out employing numerical simulation and experimental measurements of Poly-MUMPS devices. [2013-0217]

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.

This paper presents the circuit topology of a second order sigma-delta control of charge trapping for MOS capacitors. With this new topology it is possible to avoid the presence of plateaus that can be found in first-order sigma-delta modulators. Plateaus are unwanted phenomena in which the control is locked for a certain time interval (of unknown duration). In this case the control output is constant and therefore the controlled device is in fact in open-loop configuration. It is shown that the presence of plateaus is avoided in MOS capacitors using the proposed approach.

This paper presents an active control of capacitance–voltage (C–V) characteristic for MOS capacitors based on sliding-mode control and sigma–delta modulation. The capacitance of the device at a certain voltage is measured periodically and adequate voltage excitations are generated by a feedback loop to place the C–V curve at the desired target position. Experimental results are presented for an n-type c-Si MOS capacitor made with silicon dioxide. It is shown that with this approach, it is possible to shift the C–V curve horizontally to the desired operation point. A physical analysis is also presented to explain how the C–V horizontal displacements can be linked to charge trapping in the bulk of the oxide and/or in the silicon–oxide interface. Finally, design criteria are provided for tuning the main parameters of the sliding-mode controller.

This paper introduces diffusive representation as a novel approach to characterize the dynamics of charge trapped in the dielectric layers of microelectromechanical systems. 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 the pseudo random binary sequences are applied to the device. The obtained model exhibits good agreement with the experimental data and also allows us to model the behavior of the charge dynamics under excitation with arbitrary binary signals.

This paper presents a new approach for automatic supervision and remote fault detection of grid connected photovoltaic (PV) systems by means of OPC technology-based monitoring. The use of standard OPC for monitoring enables data acquisition from a set of devices that use different communication protocols as inverters or other electronic devices present in PV systems enabling universal connectivity and interoperability. Using the OPC standard allows promoting interoperation of software objects in distributed-heterogeneous environments and also allows incorporating in the system remote supervision and diagnosis for the evaluation of grid connected PV facilities. The supervision system analyses the monitored data and evaluates the expected behaviour of main parameters of the PV array: Output voltage, current and power. The monitored data and evaluated parameters are used by the fault detection procedure in order to identify possible faults present in the PV system. The methodology presented has been experimentally validated in the supervision of a grid connected PV system located in Spain. Results obtained show that the combination of OPC monitoring along with the supervision and fault detection procedure is a robust tool that can be very useful in the field of remote supervision and diagnosis of grid connected PV systems. The RMSE between real monitored data and results obtained from the modelling of the PV array were below 3.6% for all parameters even in cloudy days.

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 time-varying 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 systems described by any arbitrary number of poles. This allows for the first time the analysis of lumped and distributed systems without any limitation on the number of poles describing it.

Modern CMOS integrated technologies integrate a variety of complex multi-physics components which contribute a growing number of challenges in the circuit design. This paper is focused on the description of the requirements and technical aspects which should be considered for successful circuit design involving capacitive MEMS. To illustrate the process, the design of an input stage for a MEMS dielectric charge bipolar control method is presented.

The purpose of this paper is to show that sigma-delta controllers of dielectric charge can be analyzed using the tools of sliding-mode controllers, in the infinite sampling frequency approximation. This allows to study the dynamics of the hidden state variables related to the charge in the dielectric, as well as the reachability and stability of the control method. Furthermore, it is also possible to explain the response of the control bitstream as a function of the dynamical model of the system. This approach not only provides insight into the dynamics of the charge controllers, understood as hybrid systems, it also simplifies the modeling and simulations of the system.

This paper reports and discusses the design and ground tests of a CubeSat payload which allows to measure, in-situ and in real time, the degradation of a polymer of electronic interest due to atomic oxygen etching in LEO. It provides real-time information on how the degradation occurs, eliminating the need to work with samples recovered once the mission has finished. The polymer, TIPS-Pentacene, is deposited on the surface of a microelectromechanical (MEMS) cantilever, which works as a resonator embedded in a Pulsed Digital Oscillator circuit. The mass losses in the polymer due to atomic oxygen corrosion produce variations in the resonant frequency of the MEMS, which is continuously sensed by the circuit and transmitted to the ground. This way, polymer mass losses around 10-12 kg can be detected during the mission. The payload is a part of the 3Cat-1 mission, a nano-satellite aimed at carrying out several scientific experiments.

This letter presents a double closed loop for simultaneously controlling the net dielectric charge and the device capacitance in contactless electrostatic MEMS devices. The first loop controls the net charge trapped in the dielectric layer by continuously monitoring the horizontal displacement of the $C$ – $V$ characteristic and applying bipolar actuation voltages to keep such net charge at the target value. The second loop adapts the actuation voltages so that the measured capacitance matches a desired value while maintaining the primary control of charge. [2015-0216]

The objective of this letter is to show the first results obtained with a control designed to keep the average surface potential of a nanostructured layerconstant. This condition is equivalent to keeping constant the resistivity of the layer measured at a constant reference temperature. The proposed closed-loop control achieves this objective by adequately changing the average temperature of the temperature waveforms applied to the nanostructured layer. Experiments are shown on which the control is applied to a layer made of Au-functionalized WO3 nanoneedles.

International audience; The aim of this paper is to formalise the term “complexity” in the context of modern microelectronics, propose the definitions of key terms and discuss a case study. Our aim is to show that the term “complex system” is implicitly related to the design of electronic systems.

This chapter discusses a variety of system structures for microelectromechanical systems (MEMS) that employ a feedback loop inspired by sigma-delta modulation. Sigma-delta modulators are classic electronic circuits that implement data conversion. The feedback loop typical for sigma-delta modulation can be applied to actuate a MEMS device or control its state. The dynamics of such systems are described by a set of discrete-time equations (map). We show how these maps can be derived for different examples of MEMS and highlight the dynamics that are universal for all examples.

Dielectric charging of insulating films in microelectromechanical systems (MEMS) has a crucial effect on the operation of those devices. A new method is presented in order to characterize the dynamics of the charge trapped in the dielectric layer of MEMS devices. This allows knowing the state of the charge at each sampling time without distorting the measurement. This approach allows one to model the expected behaviour of the trapped charge inside the dielectric as a response to a sigma-delta control of charge. The goodness of the proposed approach is obtained by matching the experimentally obtained closed loop response with the one predicted by the model obtained using the proposed characterization method.

A novel spherically shaped thermal anemometer for low pressure, Mars-like conditions, is described. The concept has been designed using finite element multyphysics simulations to find out the thermal conductance to the ambient for varying conditions of wind speed and direction and ambient pressure and temperature. A prototype 1cm diameter suitable to work under these environment in the range 0.25-10m/s speed has been build using 3D printing and tested inside a low pressure chamber. The protopype shown has two separated hemispheres, independently heated above the ambient temperature, providing angle sensitivity in one plane. Measurements of the heating power in both hemispheres required to keep an overheat of 30K are shown as a function of the wind direction showing good sensitivity at 0.5m/s. One improvement of this sensor is the means provided to also heat the core of the sphere where the circuit board is located thereby avoiding most of the conduction losses to the supports. The concept is scalable to other wind speed and pressure conditions and also to full 3D measurements.

The purpose of this work is to show that it is possible to excite selectively different resonant modes of a MEMS resonator, by simply changing some parameters in the feedback filter of Pulsed Digital Oscillators (PDOs). Extensive simulation and experimental results are presented showing the goodness of the proposed approach. An iterative map, contemplating more than one resonance, is also obtained from the equation governing the motion of a cantilever.

This paper establishes a link between closed-loop controls for heterogeneous systems and sliding mode controls. We demonstrate that sliding mode analysis matches with experimental results from dielectric charge controllers. This approach provides a new way to analyze the behaviour of different heterogeneous systems.

A new circuit is described which applies a configurable voltage across an RTD while the current flowing through it is measured with a current mirror. The circuit also allows working with voltages above the IC supply voltage to cope with the high power RTD dissipation normally required in thermal anemometers. The circuit is periodically calibrated to cancel the errors and amplifier offset and therefore improves measurement accuracy. Experimental measurements of the circuit fabricated using 0.35 mu m AMS technology show the functionality and improved power efficiency.