Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Assignment#01: Literature Survey on Sensors and Actuators Topic: Piezoelectric ActuatorsPrepared by: Saurabh BhaleraoDept. of Electrical and Computer Engineering Utah State UniversityE: [email protected]/1/200903/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-2Outline –Reference list–Overview–Major applications–Basic working principle illustrated–Major specifications–Limitations03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-3Reference list•http://www.cedrat.com/en/mechatronic-products/actuators.htmlFor the applications and manufacturing details•http://www.trstechnologies.com/Products/actuators.phpFurther reading–http://optics.nasa.gov/tech_days/tech_days_2005/docs/33%20JPL%20MEMS%20Actuators.pdf–http://motion-controls.globalspec.com/Industrial-Directory/piezoelectric_actuator–http://www.morganelectroceramics.com/tutorials/piezoguide1.html03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-4To explore further (survival pointers of web references etc) •http://www.draper.com/digest2000/paper7.pdf•http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1627332•http://www.physikinstrumente.com/tutorial/index.htmOverview•The three simplest piezoelectric actuator designs are :- a.)the cylindrical actuator b.) the bimorph (and unimorph) actuator c.) multilayer actuator03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-5Overview – Piezoelectric Actuators03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-6Groups of unit cells with the same orientation are called Weiss domains. Because of the random distribution of the domain orientations in the ceramic material no macroscopic piezoelectric behavior is observable. Diagram from:http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=400600.00Overview Contd03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-7 Due to the ferroelectric nature of the material, it is possible to force permanent alignment of the different domains using a strong electric field. This process is called poling (see Fig). Some PZT ceramics must be poled at an elevated temperature. Diagram from:http://www.physikinstrumente.com/en/products/primages.php?sortnr=400600.00&picview=2#galleryMajor Applications•Optics & Vision: Positioning of mirrors or lenses, micro-scanning, Astronomy, Focusing, Laser cavity tuning, Alignment or deformation of fibers, Deformation of FBG, Scanners, Choppers, Interferomoters, PDP glass cutting, Modulators,. •Mechanics: Positioning of tools, Pick & Place, Diamond turning, Oval piston machining, Damping, Active control, Generation of ultrasonic or sonic vibrations, NDT, Health monitoring. •Fluidics: Proportional valves, Pumps, Measuring, Injections, Ink jet, Droplet generators, Flow mass meter. •Electronics: Positioning of masks, wafers or magnetic heads, Non-magnetic actuation, Circuit breakers, Chip testing. •Air & space: Active flaps, Shape control, Active wing.•Electrical energy: Piezoelectric generator, Energy harvesting, Electric switch. 03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-8Major Advantages•Small•Lightweight•Passive•Low power•Wide bandwidth•Rugged•Resistant to EM interference•High sensitivity03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-9Principle of Operation03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-10When operated well below the resonant frequency, a piezo actuator behaves as a capacitor: The actuator displacement is proportional to stored charge (first order estimate). The capacitance of the actuator depends on the area and thickness of the ceramic, as well as on its material propertiesDiagram from:http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=400600.75Principles #203/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-11•Maximum Applicable Forces (Compressive Load Limit, Tensile Load Limit) :- The mechanical strength values of PZT ceramic material (given in the literature) are often confused with the practical long-term load capacity of a piezo actuator. PZT ceramic material can withstand pressures up to 250 MPa (250 x 106 N/m2) without breakingDiagram from:http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=400600.40Principles #303/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-12Diagram from:http://www.physikinstrumente.com/en/products/primages.php?sortnr=400600.60&picview=3#galleryEvery time the piezo drive voltage changes, the piezo element changes its dimensions. Due to the inertia of the piezo actuator mass (plus any additional load), a rapid move will generate a force acting on (pushing or pulling) the piezo.Control of Piezo Actuators03/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-13Position Servo-ControlPosition servo-control eliminates nonlinear behavior of piezoceramics such as hysteresis and creep and is the key to highly repeatable nanometric motion. Diagram from:Fiber Optic Sensor Workbook, Eric UddCourtesy: Andrew Moss optic fiber sensorsControls= #203/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-14Diagram from:http://www.physikinstrumente.com/en/products/primages.php?sortnr=400600.95&picview=3#galleryPosition servo-controlled piezo drives offer linearity and repeatability many times better than that of open-loop systems. The resolution (minimum incremental motion) of piezo actuators is actually better for open-loop than for closed-loop systems.Controls #303/06/09ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-15Diagram from:http://www.physikinstrumente.com/en/products/prdetail.php?sortnr=400600.95 In open-loop, there is no sensor or servo-electronics to put additional noise on the control signal. In a servo-controlled piezo system, the sensor and control electronics are thus of considerable importance. With appropriate, high-quality systems, subnanometer resolution is also possible in closed-loop mode. Capacitive sensors attain the highest
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