Source: http://www.google.com/patents/US7408288?dq=3723653
Timestamp: 2015-04-21 12:54:52
Document Index: 111878304

Matched Legal Cases: ['art 410', 'art 430', 'art 420', 'art 440', 'Application No. 2004', 'Application No. 2004']

Patent US7408288 - Driving apparatus - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA determination is made whether a moving speed of a slider section with respect to a rod section in a piezoelectric actuator is lower than a predetermined speed. When the moving speed is lower than the predetermined speed, it is considered that a friction-bonded portion between the rod section and the...http://www.google.com/patents/US7408288?utm_source=gb-gplus-sharePatent US7408288 - Driving apparatusAdvanced Patent SearchPublication numberUS7408288 B2Publication typeGrantApplication numberUS 11/246,737Publication dateAug 5, 2008Filing dateOct 7, 2005Priority dateOct 15, 2004Fee statusPaidAlso published asUS20060082253Publication number11246737, 246737, US 7408288 B2, US 7408288B2, US-B2-7408288, US7408288 B2, US7408288B2InventorsYoshihiro HaraOriginal AssigneeKonica Minolta Holdings, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (13), Non-Patent Citations (2), Referenced by (4), Classifications (6), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetDriving apparatus
The instruction display section 32 inputs a predetermined instruction according to a user's operation, and displays predetermined information. The instruction display section 32 is provided with operation switches including an actuating switch (power source switch) for actuating the piezoelectric driving apparatus 1 and the other switches for setting (inputting) device operations, and a monitor section such as LCD on which information such as guides and messages for operating the devices is displayed (buttons or the like for inputting instructions are also displayed) Result information (message sentence) after driving system operations are checked, such as �driving system is defective� and �position sensor is defective�, mentioned later, is displayed on the monitor section. The result information does not have to be displayed as a message sentence, and may be displayed by a method, for example, of blinking a predetermined warning lamp (or blinking display on the monitor section).
The driving speed determining section 14 has a warm-up driving section 141, a target position setting section 142, a driving time measuring section 143, a speed calculating section 144 and the like. The warm-up driving section 141 carries out predetermined warm-up driving when the driving speed check operation of the piezoelectric actuator 2 is started. The warm-up driving is such that the slider section 22 is moved from a predetermined position with respect to the rod section 21 (for example, a center position, mentioned later) to a normal direction or an opposite direction (negative direction) by a predetermined distance (for example, �0.5 mm) alternately. Moving distance information about the slider section 22 in the warm-up driving (for example, position information such as �0.5 mm) may be set in the warm-up driving section 141. The warm-up driving section 141 sets (moves) the slider section 22 to the predetermined center position with respect to the rod section 21 (this center position is not always a right-left center position of the rod section 21, and it shows a preset movement starting position).
The display control section 16 controls display of predetermined information on the instruction display section 32. For example, the display control section 16 displays result information (message sentence), such as �driving system is defective� or �position sensor is defective� after the driving system operation check is made by the driving speed determining section 14 or the low-speed countermeasure processing section 15 in the driving system operation check, on the instruction display section 32.
In the displacement-frequency relationship diagram 310, the displacement curve 301 is approximately a spike curve such that, as the driving frequency gradually increases from zero, the displacement (vibration width) becomes larger, the position of the driving frequency f3 is a peak point (maximum displacement position), and thereafter the displacement becomes smaller. The driving frequency f3 represents so-called resonance frequency of the piezoelectric actuator 2. Since also the vicinity position of the driving frequency f3 is in a resonant state (resonance phenomenon occurs), however, the resonance frequency at the peak point is called as the complete resonance frequency, and the frequency which is proximity to the complete resonance frequency at which the resonance phenomenon occurs is called as the proximity resonance frequency. In FIG. 3, the driving frequency f2 represents a frequency to be used at the time of the ordinary driving (normal driving), and for example, it obtains a value which satisfies a relationship: f2=0.7�f3 and is lower than the complete resonance frequency f3. The driving frequency f2 is set to be about 0.7 time as high as the complete resonance frequency f3 in order to efficiently obtain a displacement which is equivalent to the case where a driving frequency other than the driving frequency f2 is used (saw-tooth displacement) with small voltage amplitude (the amplitude of rectangular waves 411 and 431 can be small), avoid the complete resonance frequency f3 at which possibility that the operation becomes unstable is high, and more stably control the driving at the driving frequency to be used at the time of the ordinary driving.
The driving frequency represented by �f2�2� on the axis of abscissas (driving frequency f2�2) represents a secondary sinusoidal frequency in the case where a primary sine wave included in the driving signal, mentioned later, is the driving frequency f2. The driving frequency f1 represents a frequency in an area where the piezoelectric actuator 2 is not in the resonant state (or an influence of resonance is less), and the displacement at the driving frequency f1 is small.
In the phase-frequency relationship diagram 320, as shown by the phase curve 302, the phase of the forward end of the rod section 21 is 0 (0�) when the driving frequency is 0, and as the driving frequency becomes higher, the phase shifts to a minus side. The phase, however, changes moderately in a zone where the driving frequency is 0 to f2 (here, the phase of the driving frequency f2 is −50�), and when the driving frequency exceeds f2 (for example, in a range represented by reference numeral 303 where the displacement at the complete resonance frequency f3 and at frequencies before and after f3 becomes large), the phase abruptly changes. The phase obtains an approximately constant value in a zone thereafter up to a driving frequency f2�2 (here, the phase at the driving frequency f2�2 is −210�), namely, the phase hardly changes, so that the flat graph is obtained.
When the rectangular wave 411 shown in the driving voltage waveform chart 410 is a rectangular wave corresponding to the driving frequency f2 at the time of the ordinary driving shown in FIG. 3, for example, the frequency corresponding to a period T (an inverse (1/T)) where a period represented by reference numeral 412 is designated by �T� is the driving frequency f2. Further, the rectangular wave 411 has a zone �a� where the voltage becomes high (H) for one period and a zone �b� where the voltage becomes low (L), and the duty ratio Dt is defined as a length ratio at the high and low periods, namely, Dt=a/(a+b). Hereinafter, the duty ratio having this definition is suitably expressed by duty ratio a:b. The rectangular wave 411 here shows the case where, for example, a:b=3:7, namely, the duty ratio 3:7 (Dt=0.3 (may be expressed as 30% in percentage)). Meanwhile, in the case of the rectangular wave 431 for the opposite direction driving shown in the driving voltage waveform chart 430 in FIG. 4B, the driving frequency is the driving frequency f2 which is the same as that of the rectangular wave 411 (period shown by reference numeral 432 is the period T), and thus, for example, a:b=7:3, namely, the duty ratio 7:3 (Dt=0.7 (70%)).
The rectangular wave 411 is constituted so that the primary (term), secondary, tertiary . . . sine waves are overlapped (synthesized), namely, the rectangular wave 411 is constituted so as to include the respective order sine waves (the respective order sine wave components composing the rectangular wave can be ensured by Fourier transformation or the like). The primary sine wave corresponds to the rectangular wave 411, namely, a frequency of the primary sine wave is a frequency of the rectangular wave 411 (here, the driving frequency f2), and accordingly a frequency of the secondary sine wave is the driving frequency f2�2 (see FIG. 3). When the rectangular wave 411 (driving voltage) is applied to the piezoelectric element section 23, according displacement of the piezoelectric element section 23 and the rod section 21 (forward end) is obtained. In other words, however, the piezoelectric actuator 2 has transfer function (voltage-displacement transfer function) such that when the rectangular wave is input, predetermined displacement is output.
When the primary sine wave in the rectangular wave 411 is applied to the piezoelectric actuator 2 (piezoelectric element section 23), namely, the primary sine wave is multiplied by the transfer function, amplitude and phase of the obtained displacement waveform of the piezoelectric element section 23 and the rod section 21 do not much change from the amplitude and the phase of the primary sine wave. When the secondary sine wave is multiplied by the transfer function similarly, the amplitude does not much change, but the phase is delayed (as shown in FIG. 3, because the driving frequency f2 and the driving frequency f2�2 corresponding to the primary and secondary sine waves are in a position where they sandwich the complete resonance frequency f3, their phases shift). When high-order sine waves after the tertiary are multiplied by the transfer function, the amplitude notably reduces, and this case does not influence a displacement waveform to be obtained. For this reason, the primary and secondary sine waves are treated as the sine wave components for obtaining the displacement waveform of the piezoelectric element section 23 and the rod section 21.
Concretely, when the amplitude of the rectangular wave 411 is, for example, �1�, the amplitude of the respective order sine waves included in the rectangular wave 411 depends on the duty ratio, and a ratio in the amplitude of the primary sine wave to the secondary sine wave when Dt=0.3, for example, is about 1:0.6. When the piezoelectric actuator 2 is driven by the rectangular wave 411 including the primary and secondary sine waves, as shown in the displacement waveform chart 420, a displacement waveform 421 is obtained correspondingly to the primary sine wave, and a displacement waveform 422 is obtained correspondingly to the secondary sine wave. The amplitude ratio of the displacement waveforms 421 and 422 is about 1:0.3, and their phases are −50� and −210�, respectively (−210� is changed into −30� in the case of the opposite direction driving shown in the displacement waveform chart 440). For this reason, the displacement waveforms 421 and 422 obtained by the primary and secondary sine waves are synthesized so that a saw-tooth waveform 423 (triangular wave) which is a saw-tooth displacement waveform is obtained. In the case of FIG. 4B, similarly a displacement waveform 441 is obtained correspondingly to the primary sine wave in the rectangular wave 431, and a displacement waveform 442 is obtained correspondingly to the secondary sine wave. The displacement waveform 441 and 442 are synthesized so that a saw-tooth waveform 443 is obtained.
FIG. 7 is a flowchart illustrating one example of the operation at step S2 shown in FIG. 6. The driving frequency f2 at the time of the ordinary driving is set in the driving frequency setting section 12 (step S11). The driving speed determining section 14 checks the driving speed of the piezoelectric actuator 2 (step S12). When the determination is made that the moving speed Vd of the slider section 22 with respect to the rod section 21 is lower than the minimum speed Vmin in the speed range (YES at step S13), the low-speed countermeasure processing section 15 executes the low-speed countermeasure process (step S14) in order to eliminate the state that the moving speed is low so as to return to the normal state (return to the speed value in the speed range). When the low-speed countermeasure process is the third time (YES at step S15), the result of the driving system operation check is displayed as a message sentence �operating system is defective� on the instruction display section 32 (monitor section) so that the user is informed of this (step S16). When the low-speed countermeasure process is not the third time (NO at step S15), the sequence returns to step S12, so that the driving speed is again checked. The number-of-times information at step S15 may be set in the number-of-driving-times setting section 153. Further, the number of times at step S15 may be an arbitrary number of times other than three times, namely, two times or five times, for example.
In the case where the determination is made at step S13 that the moving speed Vd of the slider section 22 is higher than the minimum speed Vmin in the speed range (NO at step S13), when the determination is further made that the moving speed Vd is higher than the maximum speed Vmax in the speed range (YES at step S17) and the determining operation at step S17 is the second time (YES at step S18), the result of the driving system operation check is displayed as a message sentence �position sensor is defective�, which represents defect (abnormal) of the position detecting system, for example, on the instruction display section 32 (monitor section) so that the user is informed of it (step S19). When the determining operation at step S17 is not the second time (NO at step S18), the sequence returns to step S12, so that the driving speed is again checked. When the determination is made at step S17 that the moving speed Vd is not higher than the maximum speed Vmax in the speed range (NO at step S17), this case is determined as the normal driving state, and the sequence returns to the operation just after the step S2 in FIG. 6. When the piezoelectric actuator 2 is in the operation defective state or the operation disabled state, the low-speed countermeasure process at step S14 is executed. At that time, it cannot be said that the normal state is completely returned, but when once the abnormal state is eliminated, the stable driving operation can be performed thereafter.
According to the piezoelectric driving apparatus 1 of this embodiment, when the moving speed of the slider section 22 with respect to the rod section 21 is lower than a predetermined speed, the piezoelectric actuator 2 is driven by using the resonance frequency (complete resonance frequency f3) or the driving frequency to be the frequency proximity to the resonance frequency (f3�Δf) (even if the control at stable driving speed becomes difficult), so that a generative force of the actuator or an amount of displacement (amplitude) of the piezoelectric element section 23 (rod section 21) which is stronger or larger than those at the time of the ordinary driving (even if the slider section 22 is fastened to the rod section 21, a strong inertial force is generated in the slider section 22 which is vibrated together with the rod section 21 by the strong actuator generative force and the vibration having an amount of displacement in the rod section 21). As a result, since the slider section 22 can be moved against the strongly frictional state or the strongly fastened state that makes the moving speed small (zero), even if the piezoelectric actuator 2 is brought into the operation defective state or the operation disabled state, the abnormal state can be eliminated, namely, the operation defective state can be improved, or the operation disabled state can be eliminated easily and securely.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS6433459 *Sep 27, 2000Aug 13, 2002Minolta Co., Ltd.Piezoelectric actuatorUS6657362 *Sep 25, 2001Dec 2, 2003Minolta Co., Ltd.Driving apparatus and method for driving a driven memberUS6727635 *Sep 10, 2001Apr 27, 2004Minolta Co., Ltd.Driving deviceUS6954023May 29, 2003Oct 11, 2005Minolta Co., Ltd.Linear actuatorUS20020180387 *May 29, 2002Dec 5, 2002Canon Kabushiki KaishaControl apparatus for vibration type actuatorUS20030198150 *Jun 11, 2003Oct 23, 2003Matsushita Electric Industrial Co., Ltd.Disk drive apparatusUS20040013420 *Jul 11, 2003Jan 22, 2004Minolta Co., Ltd.Driving device, position controller provided with driving device, and camera provided with position controllerJP2000156986A Title not availableJP2000245177A Title not availableJP2004015864A Title not availableJPH10150786A Title not availableJPH11206156A Title not availableJPH11225488A Title not available* Cited by examinerNon-Patent CitationsReference1Japanese "Examiner's Decision of Refusal", dated Jan. 24, 2008, for counterpart Japanese Patent Application No. 2004-301519; along with an English-language translation thereof.2Japanese "Notification of Reasons for Refusal", dated Feb. 28, 2007, for counterpart Japanese Patent Application No. 2004-301519; along with an English-language partial translation thereof.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS7701115 *Apr 29, 2008Apr 20, 2010Panasonic CorporationDrive unitUS7898146Nov 20, 2009Mar 1, 2011Panasonic CorporationDrive unitUS8058771 *Jul 15, 2009Nov 15, 2011Ethicon Endo-Surgery, Inc.Ultrasonic device for cutting and coagulating with stepped outputUS8183738 *May 20, 2009May 22, 2012Panasonic CorporationControl system for oscillatory actuator* Cited by examinerClassifications U.S. Classification310/323.01, 310/317International ClassificationH01L41/09Cooperative ClassificationH02N2/025, H02N2/062European ClassificationH02N2/06BLegal EventsDateCodeEventDescriptionSep 21, 2011FPAYFee paymentYear of fee payment: 4Oct 7, 2005ASAssignmentOwner name: KONICA MINOLTA HOLDINGS, INC., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:HARA, YOSHIHIRO;REEL/FRAME:017112/0486Effective date: 20051003RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services