Piezoelectric transducer, piezoelectric actuator

Operating Characteristics of Piezoelectric Actuator

Stiffness, Load Capacity, ForceGeneration

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Operating Voltage To a first approximation, a piezoactuator is a spring-and-mass sys- tem. The stiffness of the actuator depends on the Young’s modulus of the ceramic (approx. 25 % that of steel), the cross-section andlength of the active material and anumber of other non-linear parameters (see p. 4-21). Typical actuators have stiffnesses between 1 and 2,000 N/µm and compressive limits between 10and 100,000 N. If the unit will beexposed to pulling (tensile) forces, a casing with integrated preloador an external preload spring is required. Adequate measures must be taken to protect the piezo- ceramic from shear and bending forces and from torque. Two types of piezo actuators havebecome established. Monolithic-sintered, low-voltage actuators(LVPZT) operate with potential dif- ferences up to about 100 V and are made from ceramic layers from 20 to 100 µm in thickness. Classical high-voltage actuators (HVPZT), on the other hand, are made from ceramic layers of 0.5 to 1 mmthickness and operate with poten-tial differences of up to 1000 V. High-voltage actuators can be made with larger cross-sections, making them suitable for larger loads than the more-compact, monolithic actuators.

Piezo Actuators Nanopositioning & Scanning Systems Active Optics / Steering Mirrors Tutorial: Piezo- electrics in Positioning Capacitive Position sensors Piezo Drivers & Nano- positioning controllers Hexapods / Micropositioning
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drives can be used for longer trav- el ranges.

Photonics Alignment Solutions

Resolution Piezoceramics are not subject tothe “stick slip” effect and there- fore offer theoretically unlimited resolution. In practice, the resolu- tion actually attainable is limitedby electronic and mechanical fac-tors: a) Sensor and servo-control elec-tronics (amplifier): amplifier noise and sensitivity to electromagnetic interference (EMI) affect the posi-tion stability. b) Mechanical parameters: designand mounting precision issues concerning the sensor, actuatorand preload can induce micro-fric- tion which limits resolution and accuracy.PI offers piezo actuators and posi-tioning systems that provide sub- nanometer resolution and stabili- ty. For more information, see pp. 4-15

Motion controllers Ceramic Linear motors & Stages Index
Fig. 2b. Custom linear drive with integrated NEXLINE ® Piezo-Walk ® piezomotor. Fig. 3. Example of a compact piezo nanopositioning andscanning system with integrated flexure guidance, sen-sor and motion amplifier.Fig. 2a. Ultrasonic linear piezo motors.

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