Micropositioning device with multidegrees of freedom for piezoelectric actuators and associated method
AssigneesUniversite De Franche-Comte, Ecole National Superieure De Mecanique Et Des Microtechniques
InventorsIoan Alexandru Ivan, Joël Agnus, Manitrarivo Rakotondrabe
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Abstract
A micropositioning device for a piezoelectric actuator includes a means for controlling an electric field applied to the piezoelectric actuator so as to deform the piezoelectric material, and means for simultaneous measurement of a variation of electric charge accumulated on the piezoelectric actuator resulting from the deformation; and means for acquiring measurements of the variation of electric charge, for processing these acquisitions and for estimating a displacement (x, y, z) of the piezoelectric actuator and/or an applied force.
Claims10
A micropositioning device for a piezoelectric actuator that includes at least one piezoelectric material capable of deforming when it is subjected to an electric field, the device comprising:
- means for controlling an electric field applied to the piezoelectric actuator so as to deform the piezoelectric material, and
- means for simultaneously measuring a variation in electric charge accumulated on the piezoelectric actuator as a result of the deformation;
- and
- means for acquiring measurements of the electric charge variation, for processing these acquisitions and for estimating a displacement (x, y, z) of the piezoelectric actuator and/or an applied force on the basis of the measurement of the variation in electric charge accumulated on the piezoelectric actuator, wherein the means for controlling and the means for measuring further comprises:
- a voltage generator connected in parallel to a divider bridge being composed of a first resistor and a second resistor in series, and to a first capacitor connected in series with the piezoelectric actuator,
- a charge amplifier having a first input connected to a node between the two resistors, forming a virtual ground at floating high potential, and a second input connected to a node between the first capacitor and the piezoelectric actuator,
- wherein the charge amplifier comprises an operational amplifier and a second capacitor connected between the second input and the output of the operational amplifier and the control and measurement means comprises a circuit for resetting to zero the charges present on the second capacitor.
A method for micropositioning at least one piezoelectric actuator that includes at least one piezoelectric material capable of deforming when it is subjected to an electric field and includes:
- means for controlling an electric field applied to the piezoelectric actuator so as to deform the piezoelectric material, and
- means for simultaneously measuring a variation in electric charge accumulated on the piezoelectric actuator as a result of the deformation;
- and
- means for acquiring measurements of the electric charge variation, for processing these acquisitions and for estimating a displacement (x, y, z) of the piezoelectric actuator and/or an applied force on the basis of the measurement of the variation in electric charge accumulated on the piezoelectric actuator, wherein the means for controlling and the means for measuring further includes:
- a voltage generator connected in parallel to a divider bridge being composed of a first resistor and a second resistor in series, and to a first capacitor connected in series with the piezoelectric actuator,
- a charge amplifier having a first input connected to a node between the two resistors, forming a virtual ground at floating high potential, and a second input connected to a node between the first capacitor and the piezoelectric actuator,
- wherein the charge amplifier comprises an operational amplifier and a second capacitor connected between the second input and the output of the operational amplifier and the control and measurement means comprises a circuit for resetting to zero the charges present on the second capacitor, comprising the following steps:
- controlling, by the control means, the piezoelectric actuator by applying an electric field to the piezoelectric actuator so as to deform the piezoelectric material;
- and
- simultaneously measuring, by simultaneous measurement means, a variation in electric charge accumulated on the piezoelectric actuator as a result of the deformation wherein at least one step includes acquiring the measurements of the electric charge variation, processing these acquisitions and of estimating (i) a displacement (x, y, z) of the piezoelectric actuator and/or (ii) an applied force on the basis of the measurement of the variation in electric charge accumulated on the piezoelectric actuator.
Dependencies are inferred from the claim text.