WO2015077830A1 - Systèmes et procédés de commande de transducteurs de flexion piézoélectriques - Google Patents

Systèmes et procédés de commande de transducteurs de flexion piézoélectriques Download PDF

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Publication number
WO2015077830A1
WO2015077830A1 PCT/AU2014/001088 AU2014001088W WO2015077830A1 WO 2015077830 A1 WO2015077830 A1 WO 2015077830A1 AU 2014001088 W AU2014001088 W AU 2014001088W WO 2015077830 A1 WO2015077830 A1 WO 2015077830A1
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Prior art keywords
voltage
operable
electrode
voltages
equal
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PCT/AU2014/001088
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English (en)
Inventor
Andrew Fleming
Shannon RIOS
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Newcastle Innovation Limited
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Priority claimed from AU2013904642A external-priority patent/AU2013904642A0/en
Application filed by Newcastle Innovation Limited filed Critical Newcastle Innovation Limited
Publication of WO2015077830A1 publication Critical patent/WO2015077830A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0603—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a piezoelectric bender, e.g. bimorph
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/0207—Driving circuits
    • B06B1/0223—Driving circuits for generating signals continuous in time
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/20—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators
    • H10N30/204—Piezoelectric or electrostrictive devices with electrical input and mechanical output, e.g. functioning as actuators or vibrators using bending displacement, e.g. unimorph, bimorph or multimorph cantilever or membrane benders
    • H10N30/2041—Beam type
    • H10N30/2042—Cantilevers, i.e. having one fixed end
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices
    • H10N30/80—Constructional details
    • H10N30/802—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits

Definitions

  • the present invention relates to piezoelectric actuators and in particular to systems and methods of driving piezoelectric bender type actuators. While some embodiments will be described herein with particular reference to that application, it will be appreciated that the invention is not limited to such a field of use, and is applicable in broader contexts.
  • Piezoelectric benders are a common type of piezoelectric actuator and are used in applications such as textile machines, fluid control devices and beam steering. Benders can be of the unimorph, bimorph or multimorph type. Unimorph actuators have a single piezoelectric layer bonded to a non-piezoelectric elastic plate. Conventional bimorph piezoelectric benders consist of two piezoelectric layers joined together to form a beam, usually with a centre shim sandwiched between the layers to increase the mechanical reliability. The beam is usually attached to a mount at one end in a cantilever arrangement. However it can also be simply supported or fixed on both ends.
  • the beam By controlling the voltage across the piezoelectric layers with respect to the poling direction, the beam can be made to bend up or down and extend or contract.
  • Bimorph actuators develop deflection and force when one piezoelectric layer contracts while the other layer expands.
  • Unimorph benders deflect when the single piezoelectric layer contracts or expands.
  • Multimorph benders work in a similar fashion to bimorph benders except that each piezoelectric layer is comprised of many thinner piezoelectric layers co-fired together and will alternately contract and expand about the neutral axis.
  • US Patent Application Publication 201 1/0223044 to Nakayama et al. relates to a piezoelectric element driving circuit that uses a transformer with a centre tap, diodes and a capacitor to control a piezoelectric pump by sending a series of voltage pulses to the device.
  • US Patent 8,508,104 to Kamitani et al. describes a method for driving a piezoelectric actuator in a way to suppress higher-order resonant modes. This method uses a feedback circuit to drive the piezoelectric actuator.
  • the various known methods of driving piezoelectric benders can be broadly classified into several main categories, including: series driven benders which use two wires and the poling direction of the two piezo layers are opposite; parallel driven benders, which use two wires for control and the poling direction of the two layers are aligned, one wire is connected to the centre electrode and the other wire is connected to the two outer electrodes; biased uni-polar driven benders, which require three wires and three electrodes to operate and two power supplies; and bridge driven benders.
  • a drive circuit that is responsive to the variable signal at the input for providing a drive voltage to the second electrode
  • a controller for maintaining the drive voltage within the range.
  • the controller preferably maintains the drive voltage in a range that extends substantially the full tolerance range between the upper and lower operable voltages.
  • the controller preferably includes the power supply for the drive circuit.
  • the controller preferably also includes a bias circuit providing a DC bias voltage.
  • the drive circuit preferably includes at least one amplifier configured for receiving the variable signal and outputting the drive voltage between upper and lower cut-off voltages.
  • the controller preferably controls the upper and lower cut-off voltages of the at least one amplifier.
  • Preferably one or both of the upper and lower cut-off voltages are derived from one or both of the upper and lower operable voltages.
  • the system preferably includes a single amplifier configured for outputting the drive voltage to at least the second electrode between the upper and lower cut-off voltages.
  • the drive voltage is preferably output to only a single electrode. In other embodiments the drive voltage is preferably output to the first and second electrodes. In some embodiments the system preferably includes a third electrode.
  • the bias circuit is preferably connected to at least one of the first and third electrodes.
  • the bias circuit is preferably connected to the first electrode for providing a first DC bias voltage to the first electrode.
  • the bias circuit is preferably also connected to the third electrode for providing a second DC bias voltage to the third electrode.
  • the upper cut-off voltage is preferably higher than or equal to the first DC bias voltage and the lower cut-off voltage is preferably lower than or equal to the second DC bias voltage. In some embodiments the upper cut-off voltage is preferably equal to the upper operable voltage. In some embodiments the lower cut-off voltage is preferably equal to the lower operable voltage. In other embodiments the lower cut-off voltage is preferably zero volts.
  • the first DC bias voltage is preferably equal to the sum of the upper and lower operable voltages and the second DC bias voltage is preferably zero.
  • the upper cut-off voltage is preferably equal to one half of the upper operable voltage.
  • the lower cut-off voltage is preferably equal to minus one half of the upper operable voltage.
  • the upper cut-off voltage is preferably equal to one half of the difference between the upper operable voltage and the lower operable voltage.
  • the lower cut-off voltage is equal to minus one half of the difference between the upper operable voltage and the lower operable voltage.
  • the first DC bias voltage is preferably equal to one half of the sum of the upper and lower operable voltages and the second DC bias voltage is preferably equal to minus one half of the sum of the upper and lower operable voltages.
  • the upper cut-off voltage is preferably equal to the absolute value of the minimum operable voltage and the lower cut-off voltage is preferably equal to the negative absolute value of the minimum operable voltage.
  • At least one of the electrodes is preferably electrically grounded. In other embodiments both the first and third electrodes are preferably electrically grounded.
  • the upper cut-off voltage is preferably equal to twice the absolute value of the minimum operable voltage and the lower cut-off voltage is preferably equal to zero.
  • both the first and second DC bias voltages are preferably equal to the absolute value of the minimum operable voltage.
  • the upper cut-off voltage is preferably equal to twice the absolute value of the minimum operable voltage and the lower cut-off voltage is preferably equal to negative twice the absolute value of the minimum operable voltage.
  • the first electrode is preferably held at zero volts.
  • the upper cut-off voltage is preferably equal to four times the absolute value of the minimum operable voltage and the lower cut-off voltage is preferably held at zero volts.
  • the bias circuit is preferably connected to the reference electrode. In some embodiments the bias circuit preferably provides a DC bias voltage of twice the absolute value of the minimum operable voltage to the reference electrode.
  • the bias circuit is preferably connected to the input for providing a third DC bias voltage to the variable signal.
  • the drive circuit preferably includes first and second amplifiers, the first amplifier configured for outputting the drive voltage to a first drive electrode between first upper and lower cut-off voltages and the second amplifier configured for outputting the drive voltage to a second drive electrode between second upper and lower cut-off voltages.
  • the first and second upper cut-off voltages are preferably the same and the first and second lower cut-off voltages are preferably the same.
  • the first and second upper cut-off voltages are preferably defined relative to the upper operable voltage. In some embodiments the first and second upper cut-off voltages are preferably equal to the upper operable voltage.
  • first and second upper cut-off voltages are preferably equal to the absolute value of the upper operable voltage.
  • the first and second lower cut-off voltages are preferably defined relative to the lower operable voltage. In some embodiments the first and second lower cut-off voltages are preferably equal to the lower operable voltage. In some embodiments the first and second lower cut-off voltages are preferably equal to the negative of the absolute value of the lower operable voltage.
  • the first upper cut-off voltage is preferably equal to the upper operable voltage
  • the first lower cut-off voltage is preferably equal to the lower operable voltage
  • the second upper cut-off voltage is preferably equal to the negative of the minimum operable voltage
  • the second lower cut-off voltage is preferably equal to the negative of the upper operable voltage
  • the first and second upper cut-off voltages are preferably equal to one half of the difference between the upper operable voltage and the lower operable voltage
  • the first lower cut-off voltage is preferably equal to zero volts
  • the second lower cut-off voltage is preferably equal to negative one half of the difference between the upper operable voltage and the lower operable voltage.
  • the first electrode is preferably electrically grounded.
  • the bias circuit is preferably connected to the reference electrode to provide a DC bias voltage to the first electrode.
  • the bias circuit preferably provides a first DC bias voltage to the first electrode that is derived from one or both of the upper and lower operable voltages.
  • the first DC bias voltage is preferably equal to half of the sum of the upper and lower operable voltages.
  • the bias circuit is preferably connected to the input to provide a second DC bias voltage to the variable signal prior to the amplifiers.
  • the drive circuit preferably includes a first circuit branch for providing the variable signal to the first amplifier and a second circuit branch for providing the variable signal to the second amplifier.
  • the bias circuit is preferably connected to each of the first and second circuit branches to apply a DC bias voltage to the variable signal along each circuit branch.
  • the DC bias voltage is preferably a positive DC offset.
  • the DC bias voltage applied to the variable signal in the first circuit branch is preferably positive and the DC bias voltage applied to the variable signal in the second circuit branch is preferably negative.
  • the bender device preferably includes a pair of planar piezoelectric bender layers disposed substantially parallel each other and poled in the parallel or anti-parallel with respect to each other.
  • the first electrode is preferably connected to a first side of a first bender layer
  • the second electrode is preferably connected to both a second side of the first bender layer and a first side of a second bender layer
  • the third electrode is preferably connected to a second side of the second bender layer.
  • the first electrode is preferably connected to a first side of a first bender layer
  • the second electrode is preferably connected to both a second side of the first bender layer and a first side of a second bender layer
  • the third electrode is preferably connected to a second side of the second bender layer.
  • the controller is preferably adapted to maintain the drive voltage within the tolerance range independent of the variable signal.
  • the bender device preferably includes two adjacent central layers and two or more outer layers disposed about the central layers.
  • the adjacent outer layers are preferably oppositely poled with respect to one another.
  • the controller is preferably adapted to maintain the drive voltage in substantially any range of voltages between the upper and lower operable voltages.
  • a method for driving a piezoelectric bender device being operable within a specified voltage tolerance range extending between predetermined upper and lower operable voltages, the bender device including one or more piezoelectric layers, at least a first electrode and a second electrode, the method including:
  • Figure 1 illustrates circuit diagrams of prior art configurations for driving a piezoelectric bimorph bender, panel a) showing a series configuration, panel b) showing a parallel configuration and panel c) showing a biased uni-polar configuration;
  • Figure 2 is a schematic diagram illustrating a system for driving a piezoelectric bender device according to the present invention
  • Figure 3 is a circuit diagram of a first bridged bipolar parallel poled configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention
  • Figure 4 is a circuit diagram of a second bridged bipolar parallel poled
  • Figure 5 is a circuit diagram of a first bridged bipolar series poled configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention
  • Figure 6 is a circuit diagram of a second bridged bipolar series poled configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention
  • Figure 7 is a circuit diagram of a bridged series configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention.
  • Figure 8 is a circuit diagram of a first biased bi-polar configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention
  • Figure 9 is a circuit diagram of a second biased bi-polar configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention, the configuration having symmetric power supply rails;
  • Figure 10 is a circuit diagram of a first biased uni-polar configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention
  • Figure 1 1 is a circuit diagram of a second biased uni-polar configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention, the configuration having a shifted ground voltage;
  • Figure 12 is a circuit diagram of a first parallel configuration for driving a
  • Figure 13 is a circuit diagram of a second parallel configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention, the configuration having a uni-polar drive voltage;
  • Figure 14 is a circuit diagram of a series configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention.
  • Figure 15 is a circuit diagram of a uni-polar series configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention.
  • Figure 16 is a circuit diagram of a third parallel configuration for driving a piezoelectric bimorph bender according to an embodiment of the invention, the configuration having the middle electrode grounded and the upper and lower electrodes actively driven;
  • Figure 17 is a schematic illustration of a multimorph piezoelectric bender system.
  • a system 1 for driving a piezoelectric bender device 3 being operable within a specified voltage tolerance range extending between predetermined upper and lower operable voltages ⁇ V max and V min ).
  • This tolerance range is determined by the material properties and dimensions of the piezoelectric material forming device 3 and the manner in which it is electrically driven.
  • the tolerance is typically provided by the material or system manufacturer in the product specification.
  • the operable voltage tolerance may constitute only a subset of the specified range or, alternatively, a range extending beyond that specified.
  • the upper and lower limits of this operable tolerance range are derived respectively from the poling and coercive electric fields.
  • the poling electric field is defined as the point at which an increase in electric field has little or no effect to the stress in the layer, and is usually around 1 to 2 kV/mm.
  • the coercive electric field is the point at which the piezoelectric layer will start to depolarise, and is typically between -200 to -500 V/mm.
  • a bender with layer thicknesses of 0.1 mm can tolerate a voltage of -50 V to +200 V across each layer.
  • Bender device 3 includes a mount 4, two piezoelectric layers 5 and 7 forming a bimorph bender pair and three electrodes 9, 1 1 and 13.
  • electrodes 9, 1 1 and 13 are driven by either a variable voltage or a constant voltage (including 0 V).
  • electrode 9 is disposed adjacent an upper surface 15 of layer 5.
  • Electrode 1 1 is disposed between layers 5 and 7 adjacent a lower surface 17 of layer 5 and an upper surface 19 of layer 7.
  • Electrode 13 is disposed adjacent a lower surface 21 of layer 7.
  • Electrodes 9, 1 1 and 13 are formed of a flexible conductive material and extend along substantially the whole width and length of layers 5 and 7.
  • electrodes 9, 1 1 and 13 extend only partially along the length of layers 5 and 7 and/or are rigid in structure.
  • a central shim is sandwiched between layers 5 and 7 adjacent electrode 1 1 to enhance the mechanical reliability of system 1 .
  • electrode 1 1 is split into a pair of electrodes about the central shim and driven at the same voltage so as to be electrically equivalent to a single electrode.
  • Each piezoelectric layer has a defined poling direction which specifies the preferred axis of alignment of the atoms within the piezoelectric material.
  • the orientation of the poling direction determines the orientation of the mechanical and electrical axes. Therefore, the relative orientation of piezoelectric layers in a bender device will determine the type of mechanical actuation that occurs under an applied electric field.
  • System 1 includes an input 23 for receiving a control signal in the form of a variable signal V in , which is typically an AC signal with a known frequency and amplitude.
  • V in typically an AC signal with a known frequency and amplitude.
  • typical amplitude and frequency values for V in may be in the range 0 to 360 mV and 1 to 2 kHz.
  • a drive circuit 25 is responsive to the variable signal at input 23 for providing a drive voltage V d to the one or more drive electrodes.
  • Circuit 25 includes the various electrical connections required for driving bender device 3 in different configurations as described below, including series, parallel and bridged type electrical configurations.
  • System 1 includes a controller 27 for maintaining the drive voltage within the specified voltage tolerance range.
  • Controller 27 includes one or more controllable power supplies for drive circuit 25 and/or a bias circuit for providing a DC bias voltage or voltages to one or more of the variable signal and/or constant voltage electrodes in system 1.
  • controller 27 includes a processor for selectively specifying, monitoring and/or modifying the bias voltages applied to the variable input signal and electrodes. Use of controller 27 allows system 1 to drive bender device 3 across substantially the full tolerance range between the upper and lower operable voltages using a non-specific variable signal V in . This results in improved bender deflection during operation.
  • Drive circuit 25 includes at least one amplifier 29 configured for receiving variable signal V in and outputting the drive voltage V d between upper and lower cut-off voltages which are specified by controller 27.
  • the upper and lower cut-off drive voltages are each derived from one or both of the upper and lower operable voltages ⁇ V max and V min ).
  • central electrode 1 1 is separated into two electrodes 1 1 a and 1 1 b disposed around a central shim 37 and driven at the same voltage. Electrically, electrodes 1 1 a and 1 1 b are equivalent to a single electrode.
  • FIG. 3 to 7 there is illustrated three variations of a bridged-type electrical configuration for driving piezoelectric bender device 3 including two amplifiers.
  • Figures 3 and 4 illustrate bridged bi-polar parallel poled bender systems 31 and 33 respectively.
  • Figures 5 and 6 illustrate bridged bi-polar series poled bender systems 34 and 35 respectively.
  • Figure 5 illustrates a bridged series driven bender system 36.
  • Bender device 3 extends a length L beyond mount 4 and is able to deflect an amount ⁇ from a blocking force F.
  • a central shim 37 is disposed between layers 5 and 7.
  • drive circuit 25 includes first and second amplifiers 39 and 41 .
  • Amplifier 39 is configured for outputting a first drive voltage V dl to electrode 9, which is in this case a drive electrode.
  • Amplifier 41 is configured for outputting a second drive voltage V d2 to electrode 13, which is also a drive electrode.
  • electrode 1 1 is electrically grounded and maintained at 0 volts.
  • drive circuit 25 includes a first circuit branch 43 for providing the variable signal to amplifier 39 and a second circuit branch 45 for providing the variable signal to amplifier 41 .
  • Controller 27 is adapted to provide, through a bias circuit, a voltage bias in the form of a DC offset voltage V 0 to the variable signal V in along each circuit branch.
  • controller 27 applies a positive DC bias voltage to the variable signal along branch 43 and a negative DC bias voltage to the variable signal along branch 45.
  • controller 27 applies a positive DC bias voltage to the variable signal along both branches 43 and 45.
  • controller 27 drives amplifier 39 such that drive voltage V dl is maintained between upper and lower cut-off voltages equal to V max and V min respectively. Controller 27 also drives amplifier 41 such that drive voltage V d2 is maintained between upper and lower cut-off voltages equal to —V min and—V max respectively.
  • both amplifiers 39 and 41 provide a positive gain of a and both layers 5 and 7 are poled in the same direction (given by the arrows on the respective layers).
  • amplifier 39 provides a positive gain of a and amplifier 41 provides a negative gain of —a.
  • piezoelectric layers 5 and 7 are poled in the same direction. However, a configuration with layers 5 and 7 both being poled in the opposite direction (but same relative orientation) is possible.
  • controller 27 drives both amplifier 39 and amplifier 41 such that both drive voltages V dl and V d2 are maintained between upper and lower cut-off voltages equal to V max and V min respectively.
  • amplifier 39 provides a positive gain of a
  • amplifier 41 provides a negative gain of -a.
  • Layers 5 and 7 are poled in opposite direction. However, in another embodiment, layers 5 and 7 are poled in the opposite directions to those shown in Figure 5.
  • controller 27 drives both amplifier 39 and amplifier 41 such that both drive voltages V dl and V d2 are maintained between upper and lower cut-off voltages equal to ⁇ V max - V min ) and - ⁇ V max - V min ) respectively.
  • Amplifier 39 provides a positive gain of a and amplifier 41 provides a negative gain of -a.
  • Layers 5 and 7 are poled in opposite directions. However, in another embodiment, layers 5 and 7 are poled in the opposite directions to those shown in Figure 6.
  • controller 27 drives both amplifier 39 and amplifier 41 such that both drive voltages V dl and V dl are maintained between upper and lower cut-off voltages equal to ⁇ V min ⁇ and -l ⁇ mm l respectively.
  • amplifier 39 provides a positive gain of a
  • amplifier 41 provides a negative gain of -a.
  • Layers 5 and 7 are poled in opposite directions but, in other embodiments, they may be poled in the same direction.
  • the centre electrode is not driven or biased. This configuration has the advantage of only requiring two electrodes to be accessible and therefore reduces system complexity and cost.
  • the bridged systems described above are able to be used on both aligned and opposite poled benders.
  • the advantage of using the bridged bipolar configurations of Figures 3 to 6 is the ability to use the full voltage range, and the ability to use the bender device 3 as an extender by changing the phase difference or voltage offset of the two drive signals V dl and V d2 .
  • FIG. 8 there is illustrated various systems for driving piezoelectric bender device 3 using a single amplifier.
  • FIG. 8 and 9 there are illustrated biased bi-polar electrical configurations.
  • System 47 of Figure 8 is an asymmetric system with electrode 13 electrically grounded at zero volts and controller 27 applying a bias voltage of V max + V min to electrode 9.
  • System 49 of Figure 9 is a symmetric system with controller 27 respectively applying electrodes 9 and 13 with bias voltage of ⁇ ⁇ V max + V min ) and - ⁇ ⁇ V max + V min ).
  • electrodes 9 and 13 are held at a constant voltage and central electrode 1 1 is driven with a variable voltage.
  • Systems 47 and 49 include a single amplifier 51 configured for outputting a drive voltage V d to electrode 1 1 between upper and lower cut-off voltages specified by the upper and lower operable tolerance voltages for device 3.
  • Systems 47 and 49 are electrically equivalent but offset in bias so that the variable signal V in and bias of the electrodes are equivalently offset.
  • controller 27 applies, through the bias circuit, a bias offset V 0 to variable signal V in .
  • Amplifier 51 is driven between an upper cut-off voltage of V max and a lower cutoff voltage oi V min .
  • the bias offset V 0 and the bias to electrode 9 are provided by a bias circuit connected with controller 27.
  • variable signal V in is not biased and amplifier 51 is driven between the cut-off range of ⁇ ⁇ ⁇ V max +
  • Controller 27 is connected, through a bias circuit, to electrodes 9 and 1 1 for providing the respective biases.
  • FIG. 10 and 1 1 there is illustrated biased uni-polar systems 53 and 55 with central drive electrode 1 1.
  • Systems 53 and 55 are similar but are offset in voltage with respect to electrical ground.
  • a bias voltage V 0 is applied to variable signal V in
  • amplifier 51 is driven between zero volts and V max
  • electrodes 9 and 13 are set at V max and zero volts respectively.
  • no bias is applied to the variable signal
  • amplifier 51 is driven between ⁇ ⁇ V max and electrodes 9 and 13 are biased ai ⁇ V max and - ⁇ V max respectively.
  • controller 27 applies a bias voltage offset V 0 to variable signal V in .
  • Amplifier 51 is driven between respective upper and lower cut-offs ⁇ V min ⁇ and -
  • Electrodes 9 and 13 are both electrically grounded at zero volts.
  • controller 27 applies a bias voltage offset of 1 V to variable signal V in .
  • Amplifier 51 is driven between upper cut-off 2 ⁇ V min ⁇ and lower cut-off of zero volts. Electrodes 9 and 13 are both biased to a voltage of ⁇ V min ⁇ .
  • controller 27 applies a bias voltage offset V 0 to variable signal V in .
  • V o 0 ⁇ /.
  • Amplifier 51 is driven between upper and lower cut-off voltages ⁇ 2 ⁇ V min ⁇ and electrode 13 is electrically grounded at zero volts.
  • controller 27 applies a bias voltage offset V 0 to variable signal V in .
  • V in varies between -1 V and l V
  • 1 0 1 V
  • the offset is set to other values depending on V in .
  • Amplifier 51 is driven between upper cut-off voltage 4
  • Controller 27 biases electrode 13 at 2 ⁇ V min ⁇ .
  • FIG. 16 there is illustrated a parallel driven bender system 65 wherein the drive signal V d is applied to both electrodes 9 and 13.
  • Central electrodes 1 1 a and 1 1 b are electrically grounded at zero volts.
  • Controller 27 applies a bias voltage offset V 0 to variable signal V in and amplifier 51 is driven between upper and lower cut-offs of ⁇
  • V 0 0.
  • layers 5 and 7 are poled in the same direction in system 65.
  • controller 27 determines the appropriate bias voltages and amplifier cut-off voltages. As these are independent of the variable input signal, there is no need to specify different input signals for different systems.
  • Multi-layer benders are benders that have more than two piezoelectric layers.
  • Each of the control methods described above can be implemented on a three wire, multilayer bender, such as that shown in Figure 17. Regardless of the poling direction (see the arrows on the respective layers) of the centre two layers, each additional layer is poled in the opposite direction to the previous layer as per Figure 17. Additionally, the electrode voltages alternate between the centre electrode voltage and the outer electrode voltage.
  • a multi-layer bender will require a lower driving voltage than the equivalent bimorph bender. The deflection and force is generally comparable.
  • controller 27 allows selection of the amplifier gain (a) and biasing of the variable signal and electrode voltages independent of the variable input signal. This allows substantially any input voltage to be used as long as the gain (a) and offset (V 0 ) are set accordingly.
  • System can be tailored to suit any bender system having different tolerances by simply varying the control voltages. Moreover, the system can be tailored to operate over the full voltage tolerance range of the bender device.
  • processor may refer to any device or portion of a device that processes electronic data, e.g., from registers and/or memory to transform that electronic data into other electronic data that, e.g., may be stored in registers and/or memory.
  • a "computer” or a “computing machine” or a “computing platform” may include one or more processors.
  • any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements/features that follow, but not excluding others.
  • the term comprising, when used in the claims should not be interpreted as being limitative to the means or elements or steps listed thereafter.
  • a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.
  • Coupled when used in the claims, should not be interpreted as being limited to direct connections only.
  • the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other.
  • the scope of the expression a device A coupled to a device B should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means.
  • Coupled may mean that two or more elements are either in direct physical, electrical or optical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other.

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Abstract

La présente invention concerne des systèmes et des procédés de commande de dispositifs transducteurs de flexion piézoélectriques pouvant opérer dans une plage de tolérances de tension spécifiée s'étendant entre des tensions utilisables prédéfinies haute et basse. Les dispositifs transducteurs de flexion comprennent une ou plusieurs couches piézoélectriques, au moins une électrode de référence et au moins une électrode de commande. Un mode de réalisation fournit un système (1) permettant de commander un dispositif transducteur de flexion piézoélectrique (3). Le système (1) comprend une entrée (23) destinée à recevoir un signal de variable (V in), un circuit de commande (25) qui répond au signal de variable (V in) appliqué à l'entrée pour fournir une tension de commande (V d) à une électrode de commande (11) et un organe de commande (27) destiné à maintenir la tension de commande à l'intérieur de la plage de tolérances de tension du dispositif transducteur de flexion.
PCT/AU2014/001088 2013-11-29 2014-11-28 Systèmes et procédés de commande de transducteurs de flexion piézoélectriques WO2015077830A1 (fr)

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AU2013904642 2013-11-29
AU2013904642A AU2013904642A0 (en) 2013-11-29 Systems and methods for driving piezoelectric benders

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WO2015077830A1 true WO2015077830A1 (fr) 2015-06-04

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US20210057632A1 (en) * 2018-01-12 2021-02-25 President And Fellows Of Harvard College Reconfigurable electrically controlled shape morphing dielectric elastomer device

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US4625137A (en) * 1983-12-09 1986-11-25 Nippon Telegraph & Telephone Public Corp. Piezoelectric actuator using bimorph element
US5083056A (en) * 1989-03-14 1992-01-21 Kabushiki Kaisha Toshiba Displacement generating apparatus
US20070107778A1 (en) * 2005-11-12 2007-05-17 Massachusetts Institute Of Technology Active controlled energy absorber using responsive fluids

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US4625137A (en) * 1983-12-09 1986-11-25 Nippon Telegraph & Telephone Public Corp. Piezoelectric actuator using bimorph element
US5083056A (en) * 1989-03-14 1992-01-21 Kabushiki Kaisha Toshiba Displacement generating apparatus
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210057632A1 (en) * 2018-01-12 2021-02-25 President And Fellows Of Harvard College Reconfigurable electrically controlled shape morphing dielectric elastomer device

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