Fei Comapny

Edwin Verschueren

Paul Tacx

Bart Jozef Janssen

Erik Michiel Franken

A positioning system can include a drive unit having an actuator element and a control system. The actuator element can include a piezoelectric material. The control system can be configured to select a path between a first position and a second position, identify at least one change of direction of the actuator element along the selected path, generate a hysteresis-compensated drive signal based at least in part on the change in direction, and apply the hysteresis-compensated drive signal to the actuator element to move an object along the path.

Systems and methods of hysteresis compensation

A sample holder retains a sample and can continuously rotate the sample in a single direction while the sample is exposed to a charged particle beam (CPB) or other radiation source. Typically, the CPB is strobed to produce a series of CPB images at random or arbitrary angles of rotation. The sample holder can rotate more than one complete revolution of the sample. The CPB images are used in tomographic reconstruction, and in some cases, relative rotation angles are used in the reconstruction, without input of an absolute rotation angle.

Rotating sample holder for random angle sampling in tomography

A method of producing a compensation signal to compensate for misalignment of a drive unit clamp element can include applying a clamp element drive signal to a drive unit clamp element to engage a mover element, determining a first displacement of the mover element, and determining a first compensation signal based at least in part on the first displacement. The method can further comprise applying the first compensation signal to the drive unit shear elements and the clamp element drive signal to the drive unit clamp element and determining a second displacement of the mover element. If the second displacement is less than a preselected threshold, the first compensation signal can be combined with an initial shear element drive signal to produce a modified shear element drive signal. If the second displacement is greater than the preselected threshold, a second compensation signal can be determined.

Systems and methods of clamp compensation

A method of producing a compensation signal to compensate for misalignment of a drive unit clamp element can include applying a clamp element drive signal to a drive unit clamp element to engage a mover element. A first displacement of the mover element can be determined. A first compensation signal to be applied to one or more drive unit shear elements can be determined based at least in part on the first displacement. The first compensation signal can be applied to the one or more drive unit shear elements and the clamp element drive signal can be applied to the drive unit clamp element. A second displacement can be determined in response to the application of the first compensation signal and the clamp element drive signal. The second displacement can then be compared to a preselected threshold. For a second displacement less than the preselected threshold, combining the first compensation signal with an initial shear element drive signal to produce a modified shear element drive signal, and for a second displacement greater than the preselected threshold, determining a second compensation signal to be applied to the one or more drive unit shear elements.

To compensate for hysteresis in an actuator, a path between a first position and a second position can be selected, and a drive signal can be applied to an actuator element that includes a hysteresis-compensated portion to move an object along the selected path.

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Mierlo, Netherlands

Edwin Verschueren