Statistically driven rate stabilizing device

Abstract

The present invention addresses the problem of providing a rate stabilizing device for a timepiece, capable of stabilizing a rate over a long period with extremely low power consumption without directly introducing mechanical vibration into a balance while using an external reference.　Provided is a rate stabilizing device for a mechanical timepiece, which is based on a statistical drive system with a constant pulse width and amplitude and which autonomously switches between four modes, namely, a normal mode by phase shift, a ΔΣ1-bit stream mode, a low-detune frequency hopping mode, and a chirp search mode, in accordance with current consumption records. The present invention achieves both rate stability and low power consumption while maintaining constant instantaneous energy without modifying a hairspring at all.

Description

Statistical-driven rate stabilizer 【0001】 The present invention relates to a time stabilization device for a mechanical watch that stabilizes the long-term rate of the balance wheel of a mechanical watch by optimizing energy injection through stochastic modulation. 【0002】 Mechanical watches have a balance wheel's natural frequency F, which is affected by the torque fluctuations of the mainspring, temperature, positional differences, and external shocks. ０ Because the spring stiffness k or damping c fluctuates slightly, long-term rate errors are unavoidable. Conventionally, pulse control methods that instantaneously modulate spring stiffness k or damping c to inject energy are known, but because the instantaneous pulse energy is variable, Q-factor degradation and increased power consumption have been problems. 【0003】 Patent Document 1 discloses a method for maintaining and adjusting the frequency of a clock resonator mechanism to near its natural frequency (ω0), which involves implementing at least one regulator device that acts on the resonator mechanism by periodic motion to bring about periodic modulation of the resonant frequency, quality coefficient (Q), or position of the stationary point of the resonator mechanism at an adjustment frequency (ωR) that is an integer multiple of the natural frequency (ω0) from 0.9 to 1.1 times, where the integer is between 2 and 10. However, this method brings about periodic modulation of at least one of the resonant frequency, quality coefficient (Q), and stationary point at an adjustment frequency that is a periodic motion, and does not involve detecting the phase of the balance wheel and controlling the oscillation of the adjustment frequency according to the phase difference with a reference oscillation to maintain and adjust the frequency of the clock resonator mechanism to near its natural frequency (ω0). 【0004】 Patent Document 2 describes a watch movement that uses electronic control to excite and maintain the oscillation of a balance oscillator with a piezoelectric spring. By controlling the voltage applied to the piezoelectric spring, the mechanical escapement is not driven, and the escapement functions as a counter. This reduces mechanical energy consumption from the barrel and significantly increases the power reserve. Furthermore, stable control of amplitude and frequency is possible through electrical control, improving the accuracy of the watch. Frequency locking in conjunction with a quartz oscillator is also possible, but this method replaces the "hairspring" with a "piezoelectric spring," which is a material modification characteristic of mechanical watches. 【0005】Patent Document 3 describes a method for finely adjusting the frequency of a watch's resonant mechanism (particularly a spring-type balance wheel) without disassembly. A femtosecond laser induces irreversible minute expansion inside a glass actuator, adjusting the position of the inertial mass with nano-precision to control the oscillation frequency. The actuator functions in both the gain and loss directions and can be controlled dynamically or statically, enabling high-precision, non-contact adjustment. However, there were problems such as the need to modify the watch body so that laser irradiation could be performed through a transparent window in the watch case (e.g., a glass back cover), and the inability to perform real-time correction to respond to dynamic changes due to the external environment (temperature, position). 【0006】 Japanese Patent Publication No. 2016-536578, Japanese Patent Publication No. 2022-185575, Japanese Patent Publication No. 2023-97393 【0007】 The objective of the present invention is to provide a statistically driven rate stabilization device that can stabilize the rate over a long period of time with extremely low power consumption, without directly injecting mechanical vibrations into the balance wheel, while utilizing an external reference. 【0008】 In a first aspect of the present invention, a rate stabilization device for a mechanical watch that does not modify the hairspring, comprising: a) at least one detection means selected from an optical reflection sensor or a magnetic sensor for non-contact detection of balance amplitude A and phase φ; and b) balance natural frequency F ０ At even half-period positions, a constant pulse width tp, a constant amplitude Vp, and a constant duty cycle D ０A rate stabilization device is provided, comprising: a) a pulse generator that outputs a pulse external force command having; c) an actuator that injects pulse external force into the balance support in response to the pulse external force command; d) a circuit that operates in a rate correction mode that performs rate correction by statistically updating the pulse injection probability P(t) (0≦P≦1), which is the probability of injecting the pulse external force, based on the phase difference with an external reference oscillator, or by controlling the average duty cycle D(t) or the drive frequency; and a control circuit that stops excitation by setting P(t)=0 when the balance amplitude exceeds the upper limit A_max; wherein the device does not periodically modulate the stiffness, inertia, quality coefficient or the position of the resting point of the balance and hairspring. Here, "phase difference" refers to the phase error between the external reference oscillator and the balance. The ON / OFF of pulse external force injection sequentially updates the probability P(t) according to the sign and magnitude of the rate error, and generates a drive waveform with a ΔΣ 1-bit modulator. Since P(t) is a continuous value between 0 and 1, and the average duty cycle converges proportionally to the rate error, there is no need to periodically modulate stiffness, inertia, etc. 【0009】 Here, the control circuit may operate in a rate correction mode in which it detects the injection phase of the injection and changes the pulse injection probability P(t) in real time in proportion to the magnitude of the injection phase to perform rate correction. The "injection phase" refers to the pulse generator being 2 F ０ This refers to the phase shift angle applied to even half-period timings. 【0010】 The control circuit may operate in a rate correction mode that performs rate correction using only the average duty cycle D(t) based on a 1-bit stream generated by a ΔΣ modulator. 【0011】 The control circuit has the temperature natural frequency F ０ It may also be possible to operate in a rate correction mode that performs rate correction while pseudo-randomly hopping between multiple frequencies of ±ΔF_ppm centered around twice the frequency. 【0012】It may be configured to operate in a chirp search mode where a burst with chirp sweep of frequency is injected only when the phase difference exceeds a predetermined threshold value to achieve relocking. 【0013】 Measure the average current consumption I_avg, and when I_avg is less than the first threshold value I １ select a step correction mode in which the control circuit performs step correction only based on the average Duty ratio D(t) of the 1-bit stream generated by the ΔΣ modulator, and when I １ is greater than or equal to the second threshold value I ２ less than, the control circuit selects a step correction mode in which step correction is performed while pseudo-randomly hopping a plurality of frequencies of ±ΔF_ppm centered on twice the template specific frequency F ０ and when I ２ is greater than or equal to, a device is provided that includes a mode management circuit that selects a chirp search mode in which a burst with chirp sweep of frequency is injected only when the phase difference exceeds a predetermined threshold value to achieve relocking. 【0014】 In the device including the above mode management device, when I_avg exceeds the third threshold value I ３ or when the remaining battery level is less than 30%, it is also possible to prohibit the chirp sweep of the chirp search mode that operates only when the phase difference exceeds a predetermined threshold value. 【0015】 The displacement amount of the actuator may be within ±200 nm, and the decrease in the template quality factor due to this displacement may be less than 1%. 【0016】 In a second aspect of the present invention, in a mechanical watch step stabilization device that does not modify the hairspring, A) a fundamental driver that generates a drive signal synchronized with the template specific frequency F ０ and B) the pulse width tp, amplitude Vp, and Duty ratio D output by the driver ０A pulse generator that holds each of them constant and drives the template by injecting pulse energy Ep that is symmetric about two phase windows of phase 0 degrees ±δ and 180 degrees ±δ, and an actuator connected thereto; C) The driving is executed only under the condition that the continuous time T_cond does not exceed 6 hours, and an amplitude monitoring circuit that stops pulse injection when the template amplitude exceeds the upper limit θ_max (75 degrees) during execution; D) A conditioning control circuit that coarsely adjusts the frequency of the template within ±1000 ppm only when the execution conditions of the driving are satisfied, and during and after the driving, the pulse width tp, amplitude Vp, and Duty ratio D ０ do not change, and a step stability device is provided that does not periodically modulate the rigidity or attenuation of the template and the hairspring. 【0017】 Here, the conditioning control circuit statistically updates the pulse injection probability P(t) (0≦P≦1), which is the probability of injecting the pulse external force, based on the phase difference from the external reference oscillator when the template amplitude decays to the reference amplitude after the driving ends, or performs step correction by controlling the average Duty ratio D(t) or the driving frequency. A step correction mode, a step correction mode in which the control circuit detects the injection phase and changes the pulse injection probability P(t) in real time in proportion to the magnitude of the injection phase to perform step correction, a step correction mode in which the control circuit performs step correction only with the average Duty ratio D(t) based on a 1-bit stream generated by a ΔΣ modulator, and the control circuit has the template natural frequency F ０ Any of the step correction modes of a step correction mode that performs step correction while pseudo-randomly hopping a plurality of frequencies of ±ΔF_ppm centered on twice the frequency of, or automatically switches to a chirp search mode that injects a chirp sweep burst to re-lock only when the phase difference exceeds a predetermined threshold. 【0018】 The actuator may be disposed between a receiving stone and a hole stone that support the end of the template axis or on the upper surface of the receiving stone, and may also function as a shock absorber by interposing an elastic layer on at least one surface of the actuator. 【0019】 Figure 1 is an image diagram showing the rate stabilization device of this embodiment incorporated into the body of a mechanical watch. Figure 2 is a schematic diagram of a sensor and actuator attached to a conventional vibration mechanism. Figure 3 is a cross-sectional view of the jewel bearing and jewel bearing areas showing the positions where the actuator is placed in a modified arrangement. Figure 4 is a functional block diagram showing the functional configuration of the control unit. Figure 5 is a flowchart showing the control flow with P(t) probability control of the control unit as the main layer. Figure 6 is a flowchart showing the details of the normal mode operation in step A4. Figure 7 is a flowchart showing the details of the ΔΣ 1-bit quantization mode operation B1 in the auxiliary layer of step A5. Figure 8 is a flowchart showing the details of the low detune frequency hopping mode operation B2 in the auxiliary layer of step A5. Figure 9 is a flowchart showing the details of the chirp search mode operation B3 in the auxiliary layer of step A5 and the operation of the associated pulse generator. Figure 10 is an image diagram showing the rate stabilization device of this embodiment incorporated into the body of a mechanical watch. Figure 11 is a functional block diagram showing the functional configuration of the control unit. Figure 12 shows F ０ This is a flowchart illustrating the operation of the burst conditioning mode control unit. 【0020】 A rate stabilization device for mechanical watches that uses an external reference but does not directly inject mechanical vibrations into the balance wheel, and can stabilize the rate over a long period of time with extremely low power consumption, incorporates an external reference oscillator separate from the balance wheel of the watch to which it is installed, and the balance wheel's natural frequency F ０ Twice the frequency (2F) ０ This was achieved by primarily controlling the injection of external force pulses with a fundamental excitation frequency of ) into the temperature support member with probability P(t) decimation, and by performing minute phase correction with respect to an external reference oscillator. Note that the various values ​​shown in the embodiment are merely examples and are not limited to these values; they can be changed as appropriate. 【0021】Figure 1 is an image diagram showing the mechanical watch rate stabilization device of this embodiment incorporated into the mechanical watch body. This device is configured as a system in which a sensor 1003, actuator 1004, control unit 1005, external reference oscillator 1006, and power supply block 1007 are added to a mechanical watch body 1001 which has a balance oscillator 1002, which is a conventional vibration mechanism consisting of a balance wheel, hairspring, bridge, balance bridge, etc. The control unit 1005 is electrically connected to the other components to receive detection signals, transmit control signals, and control the power supply. The power supply block 1007 consists of a button battery (1.55V), a DC-DC boost converter that boosts the voltage of the button battery to 10V, and a current monitor that monitors the average current I_avg. 【0022】 A sensor 1003 and an actuator 1004 are attached to the balance oscillator 1002. Figure 2 is a schematic diagram of the sensor and actuator attached to the balance oscillator. The sensor 1003 is built into the mechanical watch body 1001 and detects the vibration of the balance wheel 2001. The actuator 1004 is positioned between the mechanical watch body 1001 and the suspension-type balance bridge 2002 and applies a predetermined vibration. 【0023】 (Sensor) Sensor 1003 employs a CMOS optical motion sensor. The sensor used here pulses a predetermined VCSEL (Vertical-Cavity Surface-Emitting Laser) and acquires vibration data, including the frequency and amplitude of the balance wheel, by performing correlation calculations on the scattered light pattern using a light-receiving pixel array, and then transfers the data to the control unit. 【0024】 (Actuator) The piezoelectric element used as actuator 1004 is a multilayer PZT stack, and in response to the pulse external force command output by the control unit 1005, 2F ０A pulsed external force is injected into the balance wheel bridge. Here, a piezoelectric element is used as the actuator, but the actuators that can be used in this invention are not limited to this, and magnetostrictive elements, electrostatic actuators, shape memory alloy actuators, electromagnetic coils, micromachine actuators, etc., can be used as appropriate. Furthermore, the actuator is positioned between the mechanical watch body 1001 and the balance wheel bridge 2002, but the actuators that can be used in this invention are not limited to this, and methods of positioning it between or on the surface of the jewel bearings, jewel holes, etc. that constitute the balance wheel bridge can be used as appropriate. 【0025】 As a variation of the arrangement method, an arrangement method may be adopted in which the actuator is placed on the lower or upper surface of the bearing that supports the balance shaft end, and an elastic layer is interposed on at least one surface of the actuator to also serve as a shock absorber. 【0026】 (Modified Actuator Arrangement Method) Figure 3 is a cross-sectional view of the bearing stone and bore stone portion showing the position where the actuator is placed in a modified arrangement method. The balance shaft 3000 is supported at its shaft end by the bearing stone 3001 and bore stone 3002. Here, the lower surface of the bearing stone, indicated by 3003, and the upper surface of the bearing stone, indicated by 3004, can be used as positions for placing the actuator. When the method of placing the actuator on the lower surface of the bearing stone 3003 is adopted, the actuator is driven in a series direction around the bearing stone at a frequency of 2F ０ Displace it. 【0027】 (Control Unit) The operation of each functional component shown here is realized by executing a control program, such as pre-installed firmware, on a predetermined processor or dedicated hardware circuit, and by cooperating with various devices that constitute the components of this device. A microcontroller unit (hereinafter referred to as MCU) is used in the control unit 1005. The MCU refers to an external reference and calculates the phase difference Δφ with the temperature phase using a PLL method, and controls the pulse width, amplitude, duty cycle, and phase of the pulse control profile output to the pulse generator so that Δφ becomes zero. 【0028】Figure 4 is a functional block diagram showing the functional configuration of the control unit. The general configuration consists of a statistical drive control unit 4000 and a pulse generator 4008 that outputs an external force pulse command according to the pulse control profile and drive trigger generated by the statistical drive control unit. The statistical drive control unit 4000 consists of a phase difference Δφ calculation unit 4001, a probability P(t) update unit 4002, a ΔΣ Duty control unit 4003, a frequency table 4004, a chirp control unit 4005, an I_avg & amplitude monitoring unit 4006, and a mode selection unit 4007. 【0029】 The phase difference Δφ calculation unit 4001 calculates the phase difference Δφ between the external reference signal and the balance oscillator oscillation, and sends the result to the probability P(t) update unit 4002. The probability P(t) update unit 4002 updates the pulse injection probability P(t) in real time and transmits it to the pulse generator. 【0030】 The ΔΣ Duty Control Unit 4003 quantizes and noise-shapes the updated probability P(t) into a 1-bit driven trigger sequence d(n) by ΔΣ second-order modulation, and generates a pulse control profile including pulse width tp, amplitude Vp, etc., by referring to the frequency table 4004, and transmits it to the pulse generator. Furthermore, it supplies a real-time d(n) sequence to the pulse generator during initial setup / recorrection of the pulse control profile. 【0031】 Frequency table 4004 shows the balance wheel frequency (F) of the mechanical watch in question. ０ (and the frequency after temperature compensation), fine adjustment frequency (F ０ +ΔF １ F ０ +ΔF ２ , ...), frequency of higher-order synchronous series (k·F) ０ It stores the chirp frequency (k = 2 to 10). 【0032】The chirp generation unit 4005 generates a pulse control profile including a predetermined chirp signal by referring to the frequency table 4004 only when the phase difference Δφ exceeds a predetermined threshold, and supplies it to the pulse generator. The I_avg & amplitude monitoring unit 4006 monitors the average current I_avg supplied from the power supply block 1007 and the vibration amplitude of the balance wheel acquired by the sensor, and provides feedback to the above units if it deviates from the allowable range. The mode selection unit 4007 compares the average current I_avg with the rated current of the power supply block and compares the vibration amplitude of the balance wheel with the upper limit amplitude to select the operating mode of the control unit. The pulse generator 4008 outputs an external force pulse command to the actuator according to the pulse control profile generated in the selected operating mode and the drive trigger (only the drive trigger if no pulse control profile is generated). 【0033】 Figure 5 is a flowchart showing the control flow with the control of the injection probability P(t) of the control unit as the main layer. In step A1, the sensor 1003 detects the frequency F related to the operation of the balance wheel. ０ The amplitude is measured. In step A2, the control unit sets the fundamental excitation frequency to F ０ It is calculated and determined as x 2. In step A3, the reference frequency is received from the external reference oscillator 1006, the phase related to the operation of the balance wheel is estimated, and the phase difference Δφ with respect to the reference frequency is calculated. In step A4, the control unit updates the injection probability P(t) in proportion to the phase difference Δφ, and sets P=0 when the amplitude upper limit A>A_max, and 2 F is injected into the balance wheel. ０ Core control (hereinafter referred to as normal mode operation) is performed, which generates a pulse control profile and drive trigger for injecting external force pulses. In step A5, the control unit selects and activates the operation of the auxiliary layer, and the basic excitation frequency (2F) is set in proportion to the calibration amount generated by the operation of the activated operation mode. ０ The signal is modulated, phase conversion occurs, and a pulse control profile and drive trigger are generated. 【0034】The details of the auxiliary layer's operation selection and activation in step A5 are as follows. Based on the power monitor of the power supply block 1007, which measures the average current consumption I_avg, and the finite state machine (hereinafter referred to as FSM), the ΔΣ 1-bit quantization mode operation B1, the low detune frequency hopping mode operation B2, and the chirp search mode operation B3 are autonomously switched and activated according to the I_avg threshold. If no operation is activated, the operation in step A5 is skipped, and the pulse control profile and drive trigger generated in step A4 are sent to the pulse generator. Here, the first threshold I is selected in order of decreasing power. １ , second threshold I ２ and the third threshold I ３ The setting is configured, the average current consumption I_avg is measured, and I_avg is the first threshold I １ If less than I, select the ΔΣ 1-bit quantization mode operation B1, １ The above is the second threshold I ２ Select B2 for low detune frequency hopping mode operation below I ２ The chirp search mode is selected. Furthermore, I_avg is the third threshold I ３ Chirp sweeping is prohibited if the value exceeds a certain limit or if the remaining battery capacity is less than 30%. 【0035】 The ΔΣ 1-bit quantization mode operation B1 is an operation in which the control unit quantizes the injection phase of the ΔΣ quadratic loop (64 kHz) and drives the pulse generator with a 1 / 0 bit stream. This is a rate correction mode in which rate correction is performed only by the average duty cycle D(t) based on the 1-bit stream generated by the ΔΣ modulator. 【0036】 Low detune frequency hopping mode operation B2 is controlled by the control unit at 2 F ０ This operation involves hopping between eight frequencies of ±{-30, -20, -10, -5, +5, +15, +25, +30} ppm using a linear feedback shift register (hereinafter referred to as LFSR). This corresponds to the natural tempo frequency F. ０ This is a rate correction mode in which rate correction is performed by hopping between multiple frequencies of ±ΔF_ppm centered around twice the frequency of the original frequency in a pseudo-random manner. 【0037】Chirp search mode operation B3 is an operation in which the control unit injects a burst that chirps the frequency only when the phase difference exceeds a predetermined threshold, in order to relock. This is an operation mode that locks to the minimum amplitude point with a ±ΔF_ppm chirp, limited to when the phase difference threshold of the balance oscillator is exceeded. 【0038】 In step A6, the control unit generates a pulse control profile and a drive trigger, which are generated by the normal mode or the mode operation of the selected and activated auxiliary layer, and outputs them to the pulse generator. 【0039】 In step A7, the pulse generator generates a pulsed external force command according to the received pulse control profile and drive trigger, and outputs it to the actuator. 【0040】 In step A8, the actuator injects a pulsed external force into the temperature bearing according to a pulsed external force command. 【0041】 In step A9, the control unit repeats the operations from step A1. 【0042】 (Normal Mode Operation) Figure 6 is a flowchart showing the details of the normal mode operation in step A4. In step C1, the control unit acquires the reference frequency φ_ref from the external reference oscillator 1006. In step C2, when the frequency φ_meas and amplitude A of the balance oscillator are acquired from the sensor 1003, the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas acquired by the sensor. In step C3, the control unit generates the injection probability P(t) in proportion to the phase difference Δφ based on equation 1. As shown in equation 2, when the acquired amplitude A is within the amplitude upper limit, the injection probability P(t) is proportional to the phase difference Δφ, and when it exceeds the amplitude upper limit, the injection probability is set to 0. 【0043】 【0044】 【0045】In step C4, the control unit generates a pseudo-random number R(t) in the range of 0 to 1. In step C5, the control unit compares the pseudo-random number R(t) with the injection probability P(t) using a comparator based on equation 3, and determines whether or not to perform pulsed external force injection based on the comparison result, thereby quantizing the drive trigger for the external force pulse injection. 【0046】 【0047】 If the auxiliary layer in step A5 is bypassed, the pulse generator generates a pulsed external force command according to a preset pulse control profile, in accordance with the drive trigger quantized in the normal mode operation of step A4, and outputs it to the actuator. The pulse control profile at this time is set as follows: pulse width tp is approximately 2 ms (in the range of 1.5 to 3 ms), amplitude Vp is approximately 10 V (in the range of 8 to 12 V), and duty cycle D ０ The pulse width is set to 20 to 30%, and the same energy Ep is injected symmetrically across two windows with phases of 0 degrees ± 10 degrees and 180 degrees ± 10 degrees. Here, the pulse width tp and amplitude V_p are fixed, the instantaneous energy Ep of each excitation pulse is kept constant, and rate correction is performed only by the pulse injection phase. Alternatively, the control circuit may detect the pulse injection phase and change the pulse injection probability P(t) in real time in proportion to the magnitude of the detected injection phase. 【0048】 (ΔΣ 1-bit quantization operation B1) Figure 7 is a flowchart showing the details of the ΔΣ 1-bit quantization mode operation B1 in the auxiliary layer of step A5. In step D1, the control unit acquires the reference frequency φ_ref from the external reference oscillator 1006. Furthermore, in step D2, when the frequency φ_meas and amplitude A of the balance oscillator are acquired from the sensor 1003, the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas acquired by the sensor. In step D3, the 64 kHz sampling second-order ΔΣ modulator in the ΔΣ Duty control unit quantizes the detected phase error Δφ into a 1-bit driven trigger sequence d(n), applies noise shaping, and performs high-resolution encoding of the phase error. 【0049】 (Low detuned frequency hopping mode B2) Figure 8 is a flowchart showing the details of the low detuned frequency hopping mode B2 in the auxiliary layer of step A5. 【0050】 In step E1, the control unit obtains the reference frequency φ_ref from the external reference oscillator 1006. In step E2, when the frequency φ_meas and amplitude A of the balance oscillator are obtained from the sensor 1003, the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas obtained from the sensor. In step E3, the control unit determines the probability P(t) using the phase difference Δφ, the injection probability mean P_avg, and the FSM state, and converts it into a drive trigger sequence d(n). In step E4, the control unit generates a pseudo-random number index (0-7) from the 15-bit LFSR. In step E5, the control unit uses the index to determine the drive frequency by referring to the frequency table and calculates the 2F including pulse width tp, amplitude V_p, phase window ID, timer reload value, etc. ０ A pulse control profile and a drive trigger sequence d(n) are generated that hop between eight frequencies of ±{-30, -20, -10, -5, +5, +15, +25, +30} ppm, and then transmitted to the pulse generator. 【0051】 The pulse generator, having received the pulse control profile and the drive trigger sequence d(n), generates a phase window mask of 0°±δ and 180°±δ based on the drive frequency and phase window ID. It then ANDs the phase window mask with the drive trigger sequence d(n) to determine whether firing is permitted. At the permitted timing, it outputs pulses according to tp and Vp in the pulse control profile, supplying a predetermined number of pulses to the actuator within the hopping period T_h. Through these steps and the operation of the pulse generator, 2F is completed. ０ A pseudo-random hop is performed with ±ΔF_ppm (≤50ppm). 【0052】(Chirp search mode operation B3) Figure 9 is a flowchart showing the details of the chirp search mode operation B3 in the auxiliary layer of step A5 and the operation of the associated pulse generator. 【0053】 In step F1, the control unit obtains the reference frequency φ_ref from the external reference oscillator 1006. Furthermore, in step F2, when the frequency φ_meas and amplitude A of the balance oscillator are obtained from the sensor 1003, the control unit calculates the phase difference Δφ between the reference frequency φ_ref and the frequency φ_meas obtained from the sensor. In step F3, the control unit checks if the absolute value of the phase difference Δφ exceeds a predetermined threshold (here, π / 8) and the remaining battery capacity is greater than 30% (average current exceeds the second threshold I ２ If the value is greater than 2F, a relock trigger signal is generated to initiate the relock operation. In step F4, the control unit starts the chirp burst generation unit 4005 upon receiving the relock trigger signal and sets the pulse control profile and pulse enable bit sequence for the drive frequency. Here, the drive frequency is set to 2F ０ The linear chirp is set to ±200 ppm / 50 ms, pulse enable is fixed to continuous firing mode (P(t)=1), and no decimation is performed. 【0054】 In step F5, the pulse generator calculates phase windows of 0°±δ and 180°±δ in synchronization with the instantaneous frequency during the chirp and outputs them as a gating mask. In step F6, the pulse generator ANDs the phase window mask and pulse enable (always P(t)=1), and while each window is open, external force pulses are continuously generated and injected into the actuator. 【0055】 In step F7, the control unit monitors the temp amplitude and phase difference Δφ in real time and detects the moment when the amplitude exceeds a predetermined minimum value and converges to Δφ = 0 (minimum amplitude point lock condition met). In step F8, the control unit issues a stop signal when the minimum amplitude point lock condition is met and sends it to the chirp generation unit 4005. This stops the chirp frequency sweep and continuous pulse emission. 【0056】 Example 2 incorporates the statistically driven control operation of Example 1, while F under predetermined conditions ０ This is a rate stabilizer for mechanical watches that, once the burst conditioning mode is executed and predetermined transition conditions are met, transitions to a correction mode that corrects using only the pulse injection phase Δφ as shown in Example 1. Figure 10 is an image diagram showing the rate stabilizer of this embodiment incorporated into a mechanical watch body. This device is configured as a system to which a sensor 10003, actuator 10004, control unit 10005, external reference oscillator 10006, and power supply block 10007 are added to a mechanical watch body 10001 having a balance oscillator 10002, which is a conventional vibration mechanism consisting of a balance wheel, hairspring, bridge, balance bridge, etc. The control unit 10005 is electrically connected to the other components to receive detection signals, transmit control signals, and control the power supply. The power supply block 1007 consists of a button battery (1.55V), a DC-DC boost converter that boosts the voltage of the button battery to 10V, and a current monitor that monitors the average current I_avg. 【0057】 A sensor 10003 and an actuator 10004 are attached to the balance oscillator 10002. 【0058】 (Sensor) Sensor 10003 employs a CMOS optical motion sensor. The sensor used here pulses a predetermined VCSEL (Vertical-Cavity Surface-Emitting Laser) and acquires vibration data of the balance wheel by performing correlation calculations on the scattered light pattern in the light-receiving pixel array, and then transfers the data to the control unit. 【0059】 (Actuator) The piezoelectric element used as actuator 10004 is a multilayer PZT stack, and in response to the pulse external force command output by the control unit 10005, 2F ０A pulsed external force is injected into the balance bridge. Here, a piezoelectric element is used as the actuator, but the actuators that can be used in this invention are not limited to this, and magnetostrictive elements, electrostatic actuators, shape memory alloy actuators, electromagnetic coils, micromachine actuators, etc. can be used as appropriate. Furthermore, as for the arrangement of the actuator, an arrangement method is adopted in which it is placed between the mechanical watch body 10001 and the balance bridge of the balance oscillator 10002, but the arrangement method that can be adopted in this invention is not limited to this, and arrangements such as placing it between or on the surface of the jewel bearings, jewel holes, etc. that constitute the balance bridge can be used as appropriate. 【0060】 (Control Unit) The operation of each functional component shown here is realized by executing a control program, such as pre-installed firmware, on a predetermined processor or dedicated hardware circuit, and cooperating with various devices that constitute the components of this device. A microcontroller unit (hereinafter referred to as MCU) is used in the control unit 10005. It controls the pulse width, amplitude, duty cycle, and phase of the pulse control profile required for the external force pulse command. 【0061】 Figure 11 is a functional block diagram showing the functional configuration of the control unit. Rate error detection unit 11001, F ０ The general configuration consists of a burst conditioning mode operation control unit 11002, a statistical drive control unit 11003, a first pulse generator 11004, and a second pulse generator 11005 that outputs an external force pulse voltage to the actuator based on an external force pulse command output from the normal control unit. In the rate error detection unit 11001, a rate error is detected when the error rate (also denoted as e_rate in the formula) shows a value that satisfies the following formula 4, and F ０ The burst conditioning mode request flag is set, F ０ The burst conditioning mode control unit starts operating. 【0062】 【0063】 F ０The burst conditioning control unit 11002 consists of a fundamental driver 11006, a conditioning control unit 11007, a monitoring unit 11008, and an automatic mode switching unit 11009, and drives the first pulse generator 11004. The fundamental driver 11006 controls the natural temperature frequency F ０ It generates a drive signal that is synchronized with it. 【0064】 The conditioning control unit 11007 controls the external force pulse command output by the first pulse generator to roughly adjust the frequency of the Temp within ±1000 ppm, only when the driving execution conditions of "amplitude < 70 degrees and battery remaining capacity > 40%" are met. Here, the rough adjustment is performed by the pulse width tp, amplitude Vp, and duty cycle D output by the fundamental driver. ０ The adjustment is performed by keeping each constant and driving the actuator to inject symmetrical pulse energy into the balance wheel through two phase windows of 0 degrees ± δ and 180 degrees ± δ. 【0065】 The monitoring unit 11008 monitors the average current I_avg supplied from the power supply block 1007 and the vibration amplitude of the balance wheel, and provides feedback to each functional component. It also monitors the system to stop pulse injection if the temp amplitude exceeds the upper limit θ_max (75 degrees) during burst execution, as described later. 【0066】 The automatic mode switching unit 11009 switches the operating mode according to the conditions shown in the following equation 5. When the conditions are not met, the statistical drive control unit 11003 switches to normal mode operation to operate the rate stabilization device of this embodiment. If equation 5 is met, an external force pulse command is output to the first pulse generator. 【0067】 【0068】 The first pulse generator 11004 controls the pulse width tp, amplitude Vp, and duty cycle D of the drive signal output by the fundamental driver. ０Each of these is kept constant, and an external force pulse command is generated to inject symmetrical pulse energy into the temperature through two phase windows of 0 degrees ± δ and 180 degrees ± δ, and output to the actuator. 【0069】 The normal control unit 11003 is the same as the statistical correction operation control unit 4000 in Embodiment 1. The normal control unit 11003 consists of a phase difference Δφ calculation unit 11009, a probability P(t) update unit 11010, a ΔΣ Duty control unit 11012, a frequency table 11013, a chirp generation unit 11014, an I_avg & amplitude monitoring unit 11015, and a mode selection unit 11016, and their operation is the same as the operation described in the embodiment. 【0070】 (F ０ Burst conditioning operation mode) Figure 12 shows F ０ This is a flowchart illustrating the operation of the burst conditioning mode control unit. According to the operation flow shown here, the temp natural frequency F ０ Coarse adjustment is performed using symmetrical pulses synchronized with the pulses. 【0071】 In step G1, the conditioning control unit acquires the real-time frequency and balance amplitude A of the balance oscillator measured by the sensor. In step G2, if the absolute value of the rate error exceeds 60 ppm, the conditioning control unit F ０The burst conditioning mode request flag is set. In step G3, the conditioning control unit determines that the burst start conditions are met, namely that the temp amplitude A is less than 70 degrees and the remaining battery capacity is greater than 40%. The burst sequence is started. In step G4, if the burst start conditions are met, the conditioning control unit starts the burst sequence. In step G5, the conditioning control unit gradually increases the phase offset from 0 degrees to +90 degrees in increments of a few degrees (ladder-like) from the first pulse of the burst. In step G6, the conditioning control unit measures the temp amplitude A in real time at each stage of the burst, evaluates whether A has increased or decreased from the previous step, and detects the stage where the amplitude no longer increases, i.e., the phase offset at which it becomes locally maximum (hereinafter referred to as the peak phase offset). In step G7, the conditioning control unit fixes the phase difference to the peak phase offset and injects the remaining pulses thereafter (e.g., from the 150th pulse out of 512 pulses) at the peak phase offset. In step G8, the conditioning control unit terminates the burst after a predetermined number of pulses have been consumed and enters a pause period. 【0072】 (Burst Configuration) The number of pulses per burst is set to 400 to 600 (reference value 512, ≈ 128 s), the rest time T_rest between bursts is set to 5 to 15 minutes, the maximum number of bursts N_max is limited to 4 to 8 times (total continuous operation time is within 6 hours), and the monitoring unit 11008 monitors so that pulse injection is stopped if the temp amplitude exceeds the upper limit θ_max (75 degrees) during burst execution. In this embodiment, 1 burst = F ０ The system will consist of 512 pulses (approximately 128 seconds), and after each burst, a forced rest period T_rest = 10 min will be inserted to prevent heat buildup. The maximum number of bursts N_max = 6 (total operating time ≤ 4 h) will be set. 【0073】 In step G9, the conditioning control unit recalculates the rate error at the end of the pause and determines whether or not the conditions shown in formula 6 are met. 【0074】 【0075】 In step G10, if the absolute value of the error rate is within 10 ppm and satisfies equation 6, then F ０ The burst conditioning operation mode ends, and the system transitions to a correction mode in which only the pulse injection phase of the statistical drive control unit is used for correction. If equation 6 is not satisfied, the system transitions to the next burst. 【0076】 (Implementation Results) When the rate stabilization device of this embodiment was implemented and tested, the F ０ After roughly adjusting the rate error to +4 s / day using three bursts, the parametric fine-tuning mode achieved ±0.3 ppm / day. 【0077】 (Evaluation by Operating Mode) The results of the evaluation of the 28800 bph prototype by operating mode were as follows: In the normal mode controlled by the injection probability P(t), ±0.8 ppm / day was achieved. In the ΔΣ 1-bitstream mode operation, ±0.3 ppm / day was achieved. In addition, the average current was 9.2 microA, and a peak of 12 microA was confirmed in the chirp search mode operation. Table 1 shows the evaluation of current effect and rate stability by mode. The evaluation is on a 5-point scale with the number of stars, and ☆ means half a star. Five stars means the best and lowest burden, and one star means the worst and highest burden. 【0078】 【0079】Here, the definitions of the evaluation axes are as follows: Short-term accuracy: Evaluation of rate fluctuations in a window of several tens of seconds to several minutes. Long-term accuracy: Evaluation of the average daily / weekly residual difference over 24 hours to several days. Attitude tolerance: Evaluation of rate recovery after attitude testing. Average power consumption: Evaluation of additional current and driving energy in the normal locked state. Peak power: Evaluation of instantaneous power under maximum load such as searching and reacquisition. Dislodgement recovery ability: Evaluation of the ability and speed to return to the resonance point after a large dislodgement due to shock or temperature step. Mechanical stress: Evaluation of balance Q value reduction, bearing load, and wear (more stars indicate less stress). Implementation complexity: Evaluation of hardware / firmware man-hours and cost (more stars indicate simplicity). Quietness: Evaluation of low driving noise and vibration (more stars indicate quietness). 【0080】 (Comparison of Periodic Control Method and Statistical Control Method) The theoretical basis for the effectiveness of the rate correction described in Examples 1 and 2 is as follows. However, the formulas shown here are hypothetical models in which the average effect of the external force pulse is replaced with "equivalent stiffness" for analytical convenience, and in reality, the mainspring constant k_e does not change mechanically on a periodic basis. If the equivalent stiffness of the balance wheel is k(t)=ke[1+ε cos(2ωet+δφ)], then an amplitude gain G≈ε / 2 is obtained within the stable region (ε≪1, ζ≪0.01) in the Mathieu equation. By fine-tuning δφ, the average angular velocity shifts to ω0+Δω, and Δω / ω0≈(ε / 2) tan(δφ). By utilizing this relationship, the rate can be linearly corrected within a range of ±5 seconds / day. Therefore, the device of this embodiment, unlike the conventional stiffness periodic modulation method, corrects the average angular velocity using non-contact impulses. 【0081】 Table 2 is a comparative evaluation table of periodic control methods and statistical control methods. The evaluation is on a 5-point scale using the number of stars, where ☆ represents half a star. 【0082】 【0083】By providing the rate stabilization device described above, it becomes possible to improve the accuracy of existing mechanical watches to a level comparable to quartz watches without removing the balance wheel or escapement. Furthermore, since the hairspring is not modified, it is possible to greatly improve convenience and reliability without compromising the aesthetics of the watch or its traditional mechanism. Because the instantaneous energy is constant, the Q value decrease is suppressed to less than 1%. Moreover, digital control of ΔΣ 1-bit stream mode operation, narrow-range hopping mode operation, and chirp search mode operation makes it possible to achieve both a rate stability of ±0.3 ppm / day and an average current consumption of 9 to 10 microA. 【0084】 The present invention can be applied to all mechanical timekeeping devices that require long-term rate stability, including high-end mechanical wristwatches, marine chronometers for ships, and mechanical clocks. 【0085】 1001 Mechanical watch body 1002 Balance wheel oscillator 1003 Sensor 1004 Actuator 1005 Control unit 1006 External reference oscillator 1007 Power supply block

Claims

1. A rate stabilization device for a mechanical watch that does not modify the hairspring, comprising: a) at least one detection means selected from an optical reflection sensor or a magnetic sensor that non-contactly detects the balance amplitude A and phase φ; b) a pulse generator that outputs a pulse external force command having a constant pulse width tp, a constant amplitude Vp, and a constant duty cycle D0 at even half-period positions of the balance natural frequency F0; c) an actuator that injects pulse external force into the balance support in response to the pulse external force command; d) a circuit that operates in a rate correction mode that performs rate correction by statistically updating the pulse injection probability P(t) (0≦P≦1), which is the probability of injecting the pulse external force, based on the phase difference with an external reference oscillator, or by controlling the average duty cycle D(t) of the quantized pulse external force or the driving frequency of the pulse external force; and a control circuit that stops excitation by setting P(t)=0 when the balance amplitude exceeds the upper limit A_max, The device is a rate stabilization device characterized by not periodically modulating the rigidity, inertia, quality coefficient, or position of the resting point of the balance wheel and hairspring.

2. A rate stabilization device according to claim 1, characterized in that the control circuit detects the injection phase of the injection and operates in a rate correction mode in which rate correction is performed by changing the pulse injection probability P(t) in real time in proportion to the magnitude of the injection phase.

3. A rate stabilization device according to claim 1, characterized in that the control circuit operates in a rate correction mode in which rate correction is performed only by the average duty cycle D(t) based on a 1-bit stream generated by a ΔΣ modulator.

4. A rate stabilization device according to claim 1, characterized in that the control circuit operates in a rate correction mode in which rate correction is performed while pseudo-randomly hopping between multiple frequencies of ±ΔF_ppm centered on twice the natural frequency F0 of the balance wheel.

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