# US 9,520,813 B2 · Actuator drive device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,813 B2 - Document ID: US9520813B2 - Status: Granted - Kind: B2 - Application number: 14/237,804 - Filed: 2012-10-23 - Published: 2014-06-12 - Granted: 2016-12-13 - Earliest claimed: 2011-10-27 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Corporation - Inventors: Yuta Yamamoto; Shinsuke Nakazono; Akira Kurozuka - Web page: https://patentgrep.com/patent/US9520813B2 ## CPC - H02N 2/0075: {Electrical details, e.g. drive or control circuits or methods} - G02B 26/0858: {the reflecting means being moved or deformed by piezoelectric means} - H10N 30/802: {Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits} - H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract An actuator drive device is configured to drive an actuator. The actuator drive device includes a storage section for storing a drive condition of the actuator, a processor for calculating and outputting drive signal D(t) based on a drive base signal V(t) calculated based on the drive condition with respect to time t, and a generator for outputting, based on the drive signal D(t) calculated, a driving signal for driving the actuator. The drive base signal V(t) is a sum of a fundamental wave and at least one harmonic wave of the fundamental wave. The processor is operable to determine the coefficient ak such that the drive base signal V(t) changes linearly from a minimum value to a maximum value with respect to a time. This actuator drive device improves the linearity of the driving of the actuator. ## Claims ### Claim 1 An actuator drive device configured to drive an actuator which includes a driver and a drive electrode, said actuator drive device comprising: a storage section for storing a drive condition of the actuator; a processor for calculating and outputting drive signal D(t) based on a drive base signal V(t) calculated based on the drive condition with respect to time t; and a generator for outputting, based on the drive signal D(t) calculated, a driving signal to the drive electrode of the actuator for driving the driver of the actuator, wherein the actuator drive device is configured to drive the actuator in a main mode while not exciting the actuator in a mode different from the main mode, wherein the drive base signal V(t) is a sum of a fundamental wave and at least one harmonic wave of the fundamental wave, and is expressed as: V ⁡ ( t ) = A ⁢ ∑ k = 1 N ⁢ a k ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f base ⁢ kt ) , with an amplitude A, an integer N, a coefficient ak, a frequency fbase of the fundamental wave, and an integer k (1≦k≦N), wherein frequencies of the fundamental wave and the at least one harmonic wave of the fundamental wave includes a resonance frequency f0 of the main mode, wherein the mode, different from the main mode, is excited with a vibration at a resonance frequency f1, wherein an upper limit frequency out of the frequencies of the fundamental wave and the at least one harmonic wave of the fundamental wave is a frequency fBW, wherein a frequency kfbase of a harmonic wave out of the at least one harmonic wave at any order k is included within a range of fbase≦kfbase≦fBW≦f1, and wherein the processor is operable to determine the coefficient ak such that the drive base signal V(t) changes linearly from a minimum value to a maximum value with respect to a time. ### Claim 2 (depends on 1) The actuator drive device according to claim 1, wherein the processor outputs the drive base signal V(t) as the drive signal D(t). ### Claim 3 (depends on 1) The actuator drive device according to claim 1, wherein the drive signal D(t) is expressed as: D(t)=V(t)+X, with the drive base signal V(t) and a bias X. ### Claim 4 (depends on 1) The actuator drive device according to claim 1, wherein an evaluation function S is expressed as: S = ∑ T / 2 - Δ ⁢ ⁢ t T / 2 + Δ ⁢ ⁢ t ⁢  V ⁡ ( t ) - ( mt + n )  2 with a period T(=1/fbase) of the drive base signal V(t), a duration Δt which is a half of a duration from the minimum value to the maximum value, and integers m and n, and wherein the coefficient ak is determined to satisfy S/NS<0.0015 with a discrete value NS of the time t. ### Claim 5 (depends on 1) The actuator drive device according to claim 1, wherein an evaluation function S is expressed as: S = ∑ T / 2 - Δ ⁢ ⁢ t T / 2 + Δ ⁢ ⁢ t ⁢  V ′ ⁡ ( t ) - m  2 with a period T(=1/fbase) of the drive base signal V(t), a duration Δt which is a half of a duration from the minimum value to the maximum value, and an integer m, and wherein the coefficient ak is determined to satisfy S/NS<6 with a discrete value NS of the time t. ### Claim 6 (depends on 1) The actuator drive device according to claim 1, wherein an evaluation function S is expressed as: S = ∑ T / 2 - Δ ⁢ ⁢ t T / 2 + Δ ⁢ ⁢ t ⁢  V ″ ⁡ ( t )  2 with a period T(=1/fbase) of the drive base signal V(t) and a duration Δt which is a half of a duration from the minimum value to the maximum value, and wherein the coefficient ak of the harmonic wave is determined to satisfy S/NS<1100 with a discrete value NS of the time t. ### Claim 7 (depends on 1) The actuator drive device according to claim 1, wherein a highest frequency Nfbase of the at least one harmonic wave is a frequency fBW, and wherein the frequency fBW is determined by: Ad(fBW)>Au(fBW)+3 dB, with an amplitude characteristic Ad(f) (dB) of a main mode of the actuator with respect to a frequency f, and an amplitude characteristic Au(f) (dB) of an undesired mode of the actuator with respect to the frequency f. ### Claim 8 (depends on 7) The actuator drive device according to claim 7, wherein the frequency fBW is 1200 Hz. ### Claim 9 (depends on 1) The actuator drive device according to claim 1, wherein components of the drive base signal V(t) is expressed as: ak sin(2πfbasekt), and wherein at least one predetermined component of the components is removed from the drive signal D(t). ### Claim 10 (depends on 1) The actuator drive device according to claim 1, wherein the processor is operable to correct the coefficient ak in response to an ambient temperature of the actuator as to calculate the drive signal D(t). ### Claim 11 (depends on 1) The actuator drive device according to claim 1, wherein the processor is operable to correct the coefficient ak in response to a vibration of the actuator as to calculate the drive signal D(t). ### Claim 12 (depends on 1) The actuator drive device according to claim 1, wherein the drive signal D(t) is expressed as: D ⁡ ( t ) = A ⁢ ∑ k = 1 N ⁢ b k ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f base ⁢ kt + θ k ) with a coefficient bk and a phase θk, and wherein the processor is operable to correct the coefficient ak in response to a vibration of the actuator as to calculate the coefficient bk and the phase θk. ### Claim 13 (depends on 12) The actuator drive device according to claim 12, wherein the processor is operable to correct the coefficient bk and the phase θk in response to an ambient temperature of the actuator. ### Claim 14 (depends on 1) The actuator drive device according to claim 1, wherein the drive signal D(t) is expressed as: D ⁡ ( t ) = A ⁢ ∑ k = 1 N ⁢ b k ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f base ⁢ kt + θ k ) with a coefficient bk, a phase θk, and a bias X, and wherein the processor is operable to correct the coefficient ak in response to a vibration of the actuator as to calculate the coefficient bk and the phase θk. ### Claim 15 (depends on 14) The actuator drive device according to claim 14, wherein the processor is operable to correct the coefficient bk and the phase θk in response to an ambient temperature of the actuator. ### Claim 16 (depends on 1) The actuator drive device according to claim 1, wherein the drive signal D(t) is expressed as: D ⁡ ( t ) = A ⁢ ∑ k = 1 N ⁢ b k ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f base ⁢ kt + θ k ) with a coefficient bk, and wherein the processor is operable to correct the coefficient ak in response to a vibration of the actuator as to calculate the coefficient bk. ### Claim 17 (depends on 16) The actuator drive device according to claim 16, wherein the processor is operable to correct the coefficient bk in response to an ambient temperature of the actuator. ### Claim 18 (depends on 1) The actuator drive device according to claim 1, wherein the drive signal D(t) is expressed as: D ⁡ ( t ) = A ⁢ ∑ k = 1 N ⁢ b k ⁢ sin ⁡ ( 2 ⁢ π ⁢ ⁢ f base ⁢ kt ) + X with a coefficient bk and a bias X, and wherein the processor is operable to correct the coefficient ak in response to a vibration of the actuator as to calculate the coefficient bk. ### Claim 19 (depends on 18) The actuator drive device according to claim 18, wherein the processor is operable to correct the coefficient bk in response to an ambient temperature of the actuator. ### Claim 20 (depends on 1) The actuator drive device according to claim 1, wherein the processor is operable to determine the coefficient ak such that: the drive base signal changes linearly from a minimum value to a maximum value with respect to a time for a predetermined duration within a period of the fundamental wave; and the drive base signal changes not linearly from the minimum value to the maximum value with respect to a time for at least a part of a duration within the period of the fundamental wave other than the predetermined duration.