The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 22, 2002
Filed:
Jan. 24, 2000
Peter Jaenker, Garching, DE;
DaimlerChrysler AG, , DE;
Abstract
A piezoelectric actuating drive is calibrated so that displacements or movements of its actuator output beam ( ) become independent of environmental operating conditions and of piezoelectric instabilities. For this purpose an automatic determination and correlating of energizing signal values and respective displacement positions of an actuator beam ( ) are performed on the basis of first sensing or measuring striking times (t , t ) when the actuator beam ( ) encounters at least one, preferably two limit stops which limit the beam displacement caused by piezoelectric action. The change of the electric capacitance of a piezostack ( ) that displaces the actuator output beam ( ) is measured when the beam ( ) strikes a limit stop. Instead of measuring a change in the electric capacitance of the piezostack ( ), electric charge impulses may be measured at the time (t , t ) and evaluated for the correlation between the energizing control or input signal and the corresponding output beam displacement. The correlation or calibration is performed automatically by an electronic signal processing circuit when such calibration is desired in response to an operator input or it is performed automatically in response to a control program stored in a memory of the electronic signal processing circuit.