Spherical Wind Sensor for the Atmosphere of Mars

IEEE Trans. Ind. Electron.

et al. 2017

Self Cite

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.

Section: Anemometersmentioning

confidence: 99%

“…The main objective in thermal anemometers is to measure the convection heat transfer to a fluid in order to infer its velocity. In this work we will use, as a test structure, a first prototype made with two hemispheres of a spherical wind anemometer for Mars atmosphere, described elsewhere [9].…”

Section: Introductionmentioning

confidence: 99%

Heat Flow Dynamics in Thermal Systems Described by Diffusive Representation

Domínguez-Pumar

Atienza

IEEE Trans. Ind. Electron.

et al. 2017

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“…The objective of this paper is to present the latest results of a miniaturized 3D wind sensor [ 19 ]. From the Soviet Mars 2 lander to the Mars2020-Perseverance rover, many Mars missions in the past have included a meteorological station or at least a wind sensor.…”

Section: Introductionmentioning

confidence: 99%

“…In this miniaturized sensor the actively heated silicon dice have been placed inside a sphere divided in four sectors, with one die attached to each sector [ 19 ]. Even though the elements that interact with the wind have more thermal mass than in the case of the previous sensors, it has been possible to optimize the sensor geometry, fabrication process and operation control, in order to provide time responses below 1s [ 41 , 42 ].…”

Section: Introductionmentioning

confidence: 99%

Analyzing the Performance of a Miniature 3D Wind Sensor for Mars

Domínguez-Pumar

Jiménez

et al. 2020

Sensors

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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 1000–2000 range, which represent 65–130 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.

“…Two sensor prototypes of an spherical anemometer, heritage of the REMS wind sensor, will be described in this paper. The main advantages of these sensors are their spherical geometry, which eases the 3D wind speed recovery reverse algorithm [11], and the simplicity of the system itself, with only a few heating elements. Furthermore, as the heating elements are inside a metallic shell, the sensor is more robust [11].…”

Section: Introductionmentioning

confidence: 99%

Sliding mode analysis applied to improve the dynamical response of a spherical 3D wind sensor for Mars atmosphere

Atienza

Sensors and Actuators A: Physical

Gorreta

et al. 2017

Self Cite

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.