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Characterisation of magneto-rheological fluids for actuators applications
19 June 2023
Magnetorheological fluids (MRF) are magnetically controlled fluids and they find more and more industrial applications in actuation functions. These include shock absorbers, semi-active dampers, clutches, brakes, haptic actuators & devices. Several of these applications have been studied by Cedrat Technologies for its industrial customers, and a device-oriented test bench has been developed in order to characterise the magneto-mechanical properties of MRF such as the magnetisation curve, the yield stress ….
Compact sensitive piezoelectric mass balance for measurement of unconsolidated materials in space
19 June 2023
In many in-situ instruments information about the mass of the sample could aid in the interpretation of the data and portioning instruments might require an accurate sizing of the sample mass before dispensing the sample. In addition, on potential sample return missions a method to directly assess the captured sample size would be required to determine if the sampler could return or needs to continue attempting to acquire sample.
Compact, Lightweight, and Efficient Piezo-Actuation Chain for aeronautical applications
19 June 2023
Many past and on-going studies are focusing on the use of piezo-actuators for aeronautical applications. One of the trendiest topics is the use of such devices for active flow control in aircraft, in order to reduce fuel consumption and noise. However, the implementation of such systems in aircraft suffer a lack of maturity with respect to aeronautical constraints, which are: high efficiency, compactness, and lightweight. In general, the actuators are composed of ceramics integrated in a metallic shell, which makes them heavy. For driving the actuators, the power amplifiers employed are usually linear amplifiers, which have a poor efficiency, leading to bulky designs due to large heatsinks. This paper presents recent developments that have been made to cope with these issues in order to obtain a piezo-actuation chain suitable for aeronautical applications.
Contactless Position sensors for space mechanisms based on eddy current sensing
19 June 2023
For more than 20 years, CTEC has been involved in various space missions, delivering products designed for severe environment conditions (vibrations, shocks, vacuum, humidity, wide thermal range including cryogenic). Eddy current sensor (ECS) technology, using printed circuit board (PCB) for printed coils, provides both a good resolution/accuracy and a good robustness against temperature variations.These sensors are available commercially off the shelf (COTS).
Contactless Torque Sensors based on shaft torsion measurement, compatible with existing shafts
19 June 2023
The torque measurement usually comes from strain gauges bonded on a shatf. the main concern in this measurement is due to the fact that these gauges are also rotating and the integration of electronic on rotating parts is definitely a blocking point.
Control of magnetic actuators in electric contactors by current shapping
19 June 2023
Most of present electric contactors use magnetic actuators of reluctant type (so called electromagnets) that are supplied with a simple voltage source. The use of a reluctant actuator in this condition leads to a considerable force increase when the magnetic circuit is closing, which creates damaging rebounds of the electrical contacts. To have a better control of the closing dynamics, we develop an electric drive method to reduce impact speed and to improve the closing dynamics. In this method, the reluctant actuator structure is unchanged. The appropriate current shape to be injected into the actuator is determined using a calculation method.
