Bi-laminar Multilayer Benders or Bimorphs Prepared By: Brad Crook ECE 5320 Mechatronics Assignment #1

Actuator Outline References References Major Applications Major Applications Basic Working Principle Basic Working Principle Sample Configuration Sample Configuration Major Specifications Major Specifications Limitations Limitations Best Choice For Applications Best Choice For Applications Cost Values Cost Values

References services/stripe_actuators.html services/stripe_actuators.html services/stripe_actuators services/stripe_actuators hese/Piefort01.pdf hese/Piefort01.pdf s/prdetail.php?sortnr= s/prdetail.php?sortnr= s/prdetail.php?sortnr= s/prdetail.php?sortnr=103000

Major Applications Nano-positioning Nano-positioning Needle control in textile weaving Needle control in textile weaving Braille machines Braille machines Accelerometers Accelerometers Opening/closing valves Opening/closing valves Small volume pumping Small volume pumping Switching applications-touch switches Switching applications-touch switches Cooling devices Cooling devices

Basic Working Principle (cont) A bi-laminar actuator is made from a piezoelectric smart material that returns to its original shape after a force is to applied to it. A bi-laminar actuator is made from a piezoelectric smart material that returns to its original shape after a force is to applied to it. A piezoelectric material can act as both a sensor and an actuator. A piezoelectric material can act as both a sensor and an actuator.

es/stripe_actuators/stripe_background.html Basic Working Principle A flexing or bending actuator is designed to produce a relatively large mechanical deflection in response to an electrical signal. A flexing or bending actuator is designed to produce a relatively large mechanical deflection in response to an electrical signal.

es/stripe_actuators/stripe_background.html Basic Working Principle (cont.) Two thin strips of piezoelectric ceramic are bonded together, usually with the direction of polarization coinciding, and are electrically connected in parallel. Two thin strips of piezoelectric ceramic are bonded together, usually with the direction of polarization coinciding, and are electrically connected in parallel. Courtesy of American Piezo

es/stripe_actuators/stripe_background.html Basic Working Principle (cont.) When electrical input is applied, one ceramic layer expands and the other contracts, causing the actuator to flex. When electrical input is applied, one ceramic layer expands and the other contracts, causing the actuator to flex Vin>0V Vin=0V

es/stripe_actuators/stripe_background.html Basic Working Principle (cont.) Deflections are large, but blocking forces are low, relative to forces developed by stack actuators. Deflections are large, but blocking forces are low, relative to forces developed by stack actuators. Courtesy of American Piezo

es/stripe_actuators/stripe_background.html Basic Working Principle (cont.) Parallel electrical configuration ensures high sensitivity to input; bias voltage circuitry can prolong the life of the actuator by eliminating the potential for depolarizing the ceramic layers. Parallel electrical configuration ensures high sensitivity to input; bias voltage circuitry can prolong the life of the actuator by eliminating the potential for depolarizing the ceramic layers.

iefort01.pdf Sample Configuration A bilaminar design consists of two piezoelectric substrates bonded together with polarization coinciding and with an electrode sandwiched in-between. A bilaminar design consists of two piezoelectric substrates bonded together with polarization coinciding and with an electrode sandwiched in-between PZT Electrode

Sample Configuration (cont.) The outer surface is coated with the another electrode, and a laminate is placed on top to protect the actuator. The outer surface is coated with the another electrode, and a laminate is placed on top to protect the actuator Electrode PZT Electrode

Sample Configuration (cont.) The outer electrodes are tied to an optional positive or negative electrode, and the inner electrode is tied to the opposite pole of the outer. This determines the direction of bending. The outer electrodes are tied to an optional positive or negative electrode, and the inner electrode is tied to the opposite pole of the outer. This determines the direction of bending Electrode PZT Electrode + -

Sample Configuration (cont.) Other configurations are pre-bent into a C-shape that can straighten, or bend with applied voltage, or sense a forced compression. Other configurations are pre-bent into a C-shape that can straighten, or bend with applied voltage, or sense a forced compression. Courtesy of Vincent Piefort

Major Specifications Each actuator specification is described by its: Each actuator specification is described by its: 1. Dimensions- total length, free length, width, and thickness. 2. Deflection 3. Compliance 4. Blocking force 5. Resonant frequency

Major Specifications (cont.) Total Deflection is determined by the following equation. Total Deflection is determined by the following equation. Lf: free length H: Thickness V: Voltage Results are in mm

Major Specifications (cont.) Compliance is found by the equation: Compliance is found by the equation: Lf: free length H: Thickness V: Voltage Results do not have a unit

Major Specifications (cont.) Blocking Force is found by: Blocking Force is found by: Results are in N (Newtons)

Major Specifications (cont.) Resonate Frequency is found by: Resonate Frequency is found by: 3.2 x 105 x ( [ h ] / [ lf ]2 ) Lf: free length H: Thickness V: Voltage Results are in HZ (Hertz)

Limitations There are three major limitations to the bi-laminate piezoelectric actuator. There are three major limitations to the bi-laminate piezoelectric actuator. 1. The shaping of the electrodes and laminate. 2. The bandwidth. 3. Blocking force.

Limitations (cont.) The Shaping of the Laminate can be in several forms The Shaping of the Laminate can be in several forms 1. C-shape 2. Bar, rectangular 3. Disk Each shape will have a different response time, and Force when a specific Voltage is applied Each shape will have a different response time, and Force when a specific Voltage is applied

Limitations (cont.) Shaping can also effect bandwidth. Shaping can also effect bandwidth. A larger laminar area will cause the bandwidth to drop. A larger laminar area will cause the bandwidth to drop. As the bandwidth drops the response time also drops. As the bandwidth drops the response time also drops. This could either be an advantage or a disadvantage depending on the plant. This could either be an advantage or a disadvantage depending on the plant.

Limitations (cont.) Blocking force is also determined by the deflection and compliance of the laminate. Blocking force is also determined by the deflection and compliance of the laminate. This is ends up being inversely proportional to the length. This is ends up being inversely proportional to the length. The longer the lamina the less force it is able to exert The longer the lamina the less force it is able to exert

Best Choice For Application When a choice is made for a multilayer bender it usually comes down to the limitations as described above. When a choice is made for a multilayer bender it usually comes down to the limitations as described above. For a fast acting bender with a high resonate frequency a thicker shorter bender is needed. For a fast acting bender with a high resonate frequency a thicker shorter bender is needed. This type of bender would be useful for optical switching. This type of bender would be useful for optical switching.

Best Choice For Application (cont.) The shorter bender would also be more effective for high load applications. The shorter bender would also be more effective for high load applications. For an application that needs little force but a large range of movement, like a weaving machine, then a longer bender would be nice. For an application that needs little force but a large range of movement, like a weaving machine, then a longer bender would be nice.

Cost Values At this point I have not had any price quote sent to me, and I have not found any listed online. At this point I have not had any price quote sent to me, and I have not found any listed online.