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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.
Cryogenic piezo characterisation and integration For Fine Steering Tip/Tilt Mechanism
19 June 2023
High precision cryogenic applications are demanding domains that require precise knowledge of component performance. In the case of active components such as piezoelectric actuators, such knowledge includes stroke, capacitance and Coefficient of Thermal Expansion (CTE). These parameters are difficult to define with precision because of the combination of small displacements and low temperature sensor compatibilities. A high stability and low sensibility test bench is required to obtain such results
Design and evaluation of a piezo xy stage
19 June 2023
The ROSETTA/MIDAS mission of the Europeans Space Agency (ESA) intends to study the dust collected from the Wirtanen comet using an Atomic Force Microscope (AFM). This instrument utilzes an XY piezoelectric stage to achieve precise positioning in two in-plane orthogonal directions, and a Z actuator to support the needles for the analyses of dust particles in the out-of-plane direction.
Design of a 2 stages compressor for mobility applications, using compact and efficient Moving Iron Controllable Actuators
19 June 2023
An actuator is rescaled for integration into a compressor used for the liquefaction of hydrogen vapor boil off, into a propellant storage system. The goal is to evaluate the feasibility of liquid hydrogen zero boil off, for long duration storage at 20 Kelvin cryogenic liquid condition. This article presents the actuator trade off, selection and special features imposed by the application. The actuator design is presented, its characteristics are measured, and resulting performances are presented and discussed.
Design of a dynamic tribometer applied to piezoelectric Inertia Drive Motors – In situ exploration of stick-slip principle
19 June 2023
In Inertia Drive Motors, generated motion is based on stick-slip principle. Current analytical models are predictive enough to calculate qualitatively their optimal performances, such as maximal step size and speed, with relatively few input parameters. But, they do not take into account the contact life and temporal evolution of parameters as friction factor all along lifetime of IDM. So, analytical models reach their limits when precise predictions are necessary. This investigation aims at understand wear mechanisms to model temporal evolution of friction. Such an understanding requires the reconstitution of the contact life through the evaluation of 1st and 3rd body flows. To do so, a new IDM-representative tribometer is designed. First bodies – coated TA6V and polymer – are not see-through. They are replaced alternatively by an intermediate transparent first body to observe the contact dynamically and in-situ. Friction factor, step size and mean speed are also measured. Preliminary results shows that wear profiles from real IDM and tribometer are similar. Direct observations bring out particles of TA6V coating are firstly snatched, then moves in contact and finally trigs others particle detachments.
