Signal processing circuit and control device

Abstract

The signal processing circuit includes a filter that performs filter processing on an input signal, and a filter coefficient changing section that automatically changes a coefficient of the filter in accordance with a frequency of the input signal.

Description

Technical Field

[0001] This invention relates to signal processing circuits and control devices. Background Technology

[0002] Previously, a signal processing circuit was known that included a low-pass filter for removing high-frequency noise from the input signal and a high-pass filter for removing DC components from the input signal (for example, see Patent Document 1 below).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-023475 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in existing signal processing circuits, when the frequency of the input signal changes, the frequency characteristics of the filter (especially the cutoff frequency) become inappropriate, the signal produces unexpected phase shifts, and the filter may fail to operate properly.

[0008] Methods for solving problems

[0009] One embodiment of the signal processing circuit includes: a filter that filters an input signal; and a filter coefficient changing unit that automatically changes the filter coefficients according to the frequency of the input signal.

[0010] Invention Effects

[0011] According to one embodiment of the signal processing circuit, the filter can operate normally even if the frequency of the input signal changes. Attached Figure Description

[0012] Figure 1 This is a diagram showing the structure of an input device according to one embodiment.

[0013] Figure 2 This is a diagram showing the circuit structure of a signal processing circuit according to one embodiment.

[0014] Figure 3 This is a diagram illustrating an example (first example) of the hardware structure of the filter coefficient changing unit included in a signal processing circuit according to one embodiment.

[0015] Figure 4 This is a diagram illustrating an example (first example) of filter coefficient calculation performed by the calculation unit of the filter coefficient changing unit in a signal processing circuit according to one embodiment.

[0016] Figure 5This is a diagram illustrating an example (second example) of filter coefficient calculation performed by the calculation unit of the filter coefficient changing unit in a signal processing circuit according to one embodiment.

[0017] Figure 6 This is a diagram showing an example (first example) of the frequency characteristics of the filter coefficients calculated by the calculation unit of the filter coefficient changing unit of the signal processing circuit of one embodiment.

[0018] Figure 7 This is a diagram showing an example (second example) of the frequency characteristics of the filter coefficients calculated by the calculation unit of the filter coefficient changing unit of the signal processing circuit of one embodiment.

[0019] Figure 8 This is a diagram illustrating an example (second example) of the hardware structure of the filter coefficient changing unit included in a signal processing circuit according to one embodiment.

[0020] Figure 9 This is a diagram showing the structure of the input device in other embodiments.

[0021] Figure 10 This is a diagram showing the structure of a vibration generating device in other embodiments.

[0022] Figure 11 This is a diagram illustrating the structure of a frequency measurement circuit in another embodiment.

[0023] Figure 12 This is a diagram illustrating an example (first example) of the resonant frequency calculation performed by the frequency measurement circuit in other embodiments.

[0024] Figure 13 This is a diagram illustrating an example (second example) of the resonant frequency calculation performed by the frequency measurement circuit in other embodiments.

[0025] Figure 14 This is a diagram showing a comparison of the main drive signal and the auxiliary drive signal output from the control device.

[0026] Figure 15 This is a diagram showing a comparative example of the secondary drive signal output from the control device.

[0027] Figure 16 It is a diagram showing the vibration waveform of the electromagnetic actuator when the vibration of the electromagnetic actuator is braked by the auxiliary drive signal output from the existing control device.

[0028] Figure 17 It is a diagram showing the vibration waveform of the electromagnetic actuator when the vibration of the electromagnetic actuator is braked by the auxiliary drive signal output from the control device of the embodiment. Detailed Implementation

[0029] [One Implementation Method]

[0030] Hereinafter, one embodiment will be described with reference to the accompanying drawings.

[0031] (Structure of Input Device 1)

[0032] Figure 1 This is a diagram showing the structure of an input device 1 according to one embodiment. Figure 1 The input device 1 shown includes a touch panel 2, a base 3, a control device 100, and an electromagnetic actuator 150.

[0033] Touch panel 2 is an example of an "operating device". Touch panel 2 is a flat component with an operating surface that can be operated by touch. Touch panel 2, for example, has an electrostatic sensor composed of multiple detection electrodes, which detects the operator's finger touching the operating surface.

[0034] The base 3 is located on the back side of the touch panel 2 and is a flat plate that supports the touch panel 2 and the electromagnetic actuator 150.

[0035] The control device 100 controls the vibration of the electromagnetic actuator 150 to generate an action based on the touch operation of the touch panel 2.

[0036] An electromagnetic actuator 150 is disposed between the touch panel 2 and the base 3. The electromagnetic actuator 150 generates vibrations that cause the touch panel 2 to vibrate, thereby transmitting vibrations to the operator's fingers.

[0037] (Structure of vibration generating device 10)

[0038] Figure 2 This is a diagram showing the structure of a vibration generating device 10 according to one embodiment. Figure 2 In the example shown, the signal processing circuit 120 is used to control the control device 100 of the electromagnetic actuator 150. However, the use of the signal processing circuit 120 is not limited to this.

[0039] like Figure 2 As shown, the vibration generating device 10 includes a control device 100 and an electromagnetic actuator 150. The control device 100 includes a signal processing circuit 120, a drive signal generation unit 130, and a drive unit 140.

[0040] The electromagnetic actuator 150 includes a movable body 151, a plate-shaped elastic portion 152, a coil 153, and a strain sensor 154. The electromagnetic actuator 150 is configured to generate vibration by supplying current from the drive portion 140 to the coil 153, thereby displacing the movable body 151 supported by the plate-shaped elastic portion 152.

[0041] The signal processing circuit 120 is input with a detection signal detected by a strain sensor 154 (an example of a “sensor”) disposed in the electromagnetic actuator 150. The strain sensor 154 detects the strain of the plate-shaped elastic portion 152 accompanying the displacement of the movable body 151 in the electromagnetic actuator 150, and outputs a detection signal representing the detected strain of the plate-shaped elastic portion 152.

[0042] The signal processing circuit 120 performs various filtering processes on the input detection signal. Specifically, the signal processing circuit 120 includes a low-pass filter 121, a high-pass filter 122, and a phase compensation filter 123.

[0043] Low-pass filter 121 filters the input detection signal to remove high-frequency noise. High-pass filter 122 filters the input detection signal to remove DC components. Phase compensation filter 123 filters the input detection signal to adjust its phase.

[0044] Then, the signal processing circuit 120 outputs the various filtered detection signals to the drive signal generation unit 130.

[0045] Furthermore, the signal processing circuit 120 includes a filter coefficient changing unit 124. The filter coefficient changing unit 124 automatically changes the coefficients of each filter (in this embodiment, as an example, the low-pass filter 121 and the high-pass filter 122) according to the frequency of the input signal. Therefore, even if the frequency of the input signal changes, the filter coefficient changing unit 124 can ensure that each filter operates normally by automatically setting appropriate coefficients corresponding to the frequency of the input signal. In addition, the frequency of the input signal is detected by a frequency detection unit (not shown) located inside or outside the signal processing circuit 120 and input to the filter coefficient changing unit 124.

[0046] The drive signal generation unit 130 generates a main drive signal for vibrating the electromagnetic actuator 150 and supplies the main drive signal to the drive unit 140, thereby causing the drive unit 140 to control the coil 153 of the electromagnetic actuator 150 and cause the electromagnetic actuator 150 to vibrate.

[0047] In addition, the drive signal generation unit 130 generates a secondary drive signal for braking the vibration by shortening the decay period of the vibration of the electromagnetic actuator 150, and supplies the secondary drive signal to the drive unit 140, thereby causing the drive unit 140 to control the coil 153 of the electromagnetic actuator 150 to brake the vibration of the electromagnetic actuator 150.

[0048] At this time, the drive signal generation unit 130 detects the peak timing, valley timing, or zero-crossing timing of the detection signal based on the waveform of the detection signal input from the signal processing circuit 120. Furthermore, based on the timing of the detected detection signal, the drive signal generation unit 130 can supply a secondary drive signal to the drive unit 140 at an appropriate timing to effectively brake the vibration of the electromagnetic actuator 150. Moreover, regarding the specific structure for braking the vibration of the electromagnetic actuator 150, the technology disclosed in Japanese Patent Application Publication No. 2023-127739 can be used, for example.

[0049] (An example of filter change processing in the filter coefficient change unit 124 (first example))

[0050] Figure 3 This is a diagram illustrating an example (first example) of the hardware structure of the filter coefficient changing unit 124 included in a signal processing circuit 120 according to one embodiment.

[0051] exist Figure 3 In the example shown, the filter coefficient changing unit 124 includes a calculation unit 124A. The calculation unit 124A automatically calculates the changed coefficients for each of the n filters (filter 1 to filter n) included in the signal processing circuit 120 based on the frequency of the input signal, and sets the calculated coefficients.

[0052] For example, the calculation unit 124A calculates the coefficients f(x) for each of the n filters (filter 1 to filter n) using the following polynomial degree function (1).

[0053]

[0054] Among them, a0, ..., a n This represents a fixed constant. Additionally, x represents the input frequency.

[0055] Furthermore, both the low-pass filter 121 and the high-pass filter 122 have multiple (e.g., 5) coefficients. Therefore, the calculation unit 124A uses a polynomial degree function (1) and a fixed constant to calculate the multiple coefficients of the low-pass filter 121 and the multiple coefficients of the high-pass filter 122, respectively.

[0056] Therefore, the signal processing circuit 120 pre-installs appropriate polynomial degree functions (1) and fixed constants for the multiple coefficients of the low-pass filter 121 and the multiple coefficients of the high-pass filter 122.

[0057] That is, the signal processing circuit 120 in one embodiment only needs to implement the polynomial degree function (1) and fixed constant for each filter, so it can calculate the coefficients corresponding to the frequency of the input signal for each of the n filters with relatively few resources.

[0058] The filter coefficient changing unit 124 sets the coefficients calculated by the calculation unit 124A for each of the n filters. Therefore, the filter coefficient changing unit 124 can set appropriate coefficients for each of the n filters that correspond to the frequency of the input signal.

[0059] Furthermore, the computing unit 124A is implemented using digital circuitry (i.e., hardware) without a processor (i.e., software). That is, the signal processing circuit 120 in one embodiment can automatically set appropriate coefficients for the filter with relatively few resources. However, if a processor can be installed in the signal processing circuit 120, the computing unit 124A can also be implemented using a processor.

[0060] (Example of filter coefficient calculation)

[0061] Figure 4 This is a diagram illustrating an example (first example) of the calculation unit 124A of the filter coefficient changing unit 124 of a signal processing circuit 120 according to one embodiment, calculating the filter coefficients. Figure 5 This is a diagram illustrating an example (second example) of the calculation unit 124A of the filter coefficient changing unit 124 of a signal processing circuit 120 according to one embodiment, calculating the filter coefficients.

[0062] Figure 4 The filter coefficients calculated by the calculation unit 124A of the filter coefficient change unit 124 using a first-order polynomial function are compared with the coefficients of the ideal filter.

[0063] Figure 5 The filter coefficients calculated by the calculation unit 124A of the filter coefficient changing unit 124 using a second-order polynomial function are compared with the coefficients of the ideal filter.

[0064] In addition, Figure 4 as well as Figure 5 In the chart shown, the solid lines represent the coefficients calculated by the calculation unit 124A for the frequency of each input signal, and the circular plots represent the ideal coefficients for the frequency of each input signal.

[0065] like Figure 4 and Figure 5 As shown, in one embodiment of the signal processing circuit 120, the calculation unit 124A of the filter coefficient changing unit 124 calculates the filter coefficients using a first-order polynomial function or a second-order polynomial function, thereby enabling the filter coefficients to be the same as the ideal coefficients.

[0066] Furthermore, the calculation unit 124A needs to calculate the multiple coefficients of the low-pass filter 121 and the multiple coefficients of the high-pass filter 122. However, for each of these multiple coefficients, it is preferable to pre-select an appropriate one based on the characteristics of the filter coefficients, such as the simulation results, regarding whether to use a first-order polynomial function or a second-order polynomial function.

[0067] Furthermore, the selection of the degree of the polynomial function for each of the multiple coefficients can be done manually by the operator, or automatically by a processing unit (not shown) located inside or outside the signal processing circuit 120 based on the simulation results, etc.

[0068] (An example of the frequency response of filter coefficients)

[0069] Figure 6 This is a diagram showing an example (first example) of the frequency characteristics of the filter coefficients calculated by the calculation unit 124A of the filter coefficient changing unit 124 of the signal processing circuit 120 of one embodiment. Figure 7 This is a diagram showing an example (second example) of the frequency characteristics of the filter coefficients calculated by the calculation unit 124A of the filter coefficient changing unit 124 of the signal processing circuit 120 in one embodiment.

[0070] Figure 6 The frequency characteristics of the coefficients of a certain low-pass filter 121 and high-pass filter 122 calculated by the calculation unit 124A of the filter coefficient change unit 124 are compared with the frequency characteristics of the coefficients of an ideal filter.

[0071] Figure 7 The frequency characteristics of the coefficients of another low-pass filter 121 and high-pass filter 122, calculated by the calculation unit 124A of the filter coefficient change unit 124, are shown by comparing them with the ideal frequency characteristics.

[0072] In addition, Figure 6 and Figure 7 In the chart shown, the dashed line represents the frequency characteristics of the coefficients calculated by the calculation unit 124A, and the solid line represents the ideal frequency characteristics.

[0073] like Figure 6 and Figure 7 As shown, in one embodiment of the signal processing circuit 120, the calculation unit 124A of the filter coefficient changing unit 124 uses a first-order polynomial function or a second-order polynomial function to calculate the filter coefficients, thereby enabling the frequency characteristics of the filter coefficients to be the same as the ideal frequency characteristics.

[0074] (An example of filter change processing performed by the filter coefficient change unit 124 (second example))

[0075] Figure 8 This is a diagram illustrating an example (second example) of the hardware structure of the filter coefficient changing unit 124 included in a signal processing circuit 120 according to one embodiment.

[0076] exist Figure 8 In the example shown, the filter coefficient changing unit 124 includes a selection unit 124B and a memory 124C.

[0077] For each of the n filters (filter 1 to filter n) provided by the signal processing circuit 120, the memory 124C stores multiple appropriate coefficients for each range of the input signal frequency. The multiple coefficients stored in the memory 124C are pre-calculated based on simulation results, etc., and are appropriate coefficients for ensuring the proper operation of the filters.

[0078] For each of the n filters (filter 1 to filter n) provided by the signal processing circuit 120, the selection unit 124B selects a coefficient corresponding to the frequency of the input signal from a plurality of coefficients stored in the memory 124C.

[0079] That is, the signal processing circuit 120 in one embodiment only needs to implement a table with multiple coefficients in the memory 124C, so it can calculate the coefficients corresponding to the frequency of the input signal for each of the n filters with relatively few resources.

[0080] The filter coefficient changing unit 124 sets the coefficients selected by the selection unit 124B for each of the n filters. Thus, the filter coefficient changing unit 124 can set appropriate coefficients for each of the n filters that correspond to the frequency of the input signal.

[0081] Furthermore, both the low-pass filter 121 and the high-pass filter 122 have multiple (e.g., 5) coefficients. Therefore, the selection unit 124B selects the multiple coefficients of the low-pass filter 121 and the multiple coefficients of the high-pass filter 122 from the multiple coefficients stored in the memory 124C.

[0082] Therefore, in the memory 124C, for the multiple coefficients of the low-pass filter 121 and the multiple coefficients of the high-pass filter 122, multiple appropriate coefficients for each frequency of the input signal are preset respectively.

[0083] Furthermore, the selection unit 124B is implemented using digital circuitry (i.e., hardware) without a processor (i.e., software). That is, the signal processing circuit 120 in one embodiment can automatically set appropriate coefficients for the filter with relatively few resources. However, if a processor can be installed in the signal processing circuit 120, the selection unit 124B can also be implemented by a processor.

[0084] [Other Implementation Methods]

[0085] Other embodiments will be described below with reference to the accompanying drawings.

[0086] Previously, techniques for detecting the zero-crossing of a target signal and determining the frequency of the target signal based on the detection results have been disclosed (for example, see Japanese Patent Application Publication No. 2013-145146).

[0087] However, existing technologies, such as those used for braking control of vibration generating devices, cause the measured object signal to stop abruptly during emergency braking of the vibration generating device, thus making it impossible to measure the frequency of the measured object signal with high accuracy. The measured value of the resonant frequency used for braking control of the vibration generating device may be updated by inappropriate measured values.

[0088] Another embodiment of the frequency measuring circuit is a frequency measuring circuit that measures the resonant frequency of a vibration detection signal output from a sensor that detects the vibration of a vibration generating device. It includes: a frequency calculation unit that calculates a measured value of the resonant frequency; and a frequency update determination unit that, based on the measured value calculated by the frequency calculation unit, determines whether to update the measured value used for braking control of the vibration generating device using the measured value calculated by the frequency calculation unit.

[0089] According to other embodiments of the frequency measurement circuit, it is possible to determine whether to update the measured value for braking control of the vibration generating device based on the measured value of the resonant frequency, thereby preventing the measured value of the resonant frequency for braking control of the vibration generating device from being updated by inappropriate measured values.

[0090] (Structure of Input Device 1)

[0091] Figure 9 This is a diagram showing the structure of input device 1 in other embodiments. Figure 9 The input device 1 shown includes a touch panel 2, a base 3, a control device 100-2, and an electromagnetic actuator 150.

[0092] Touch panel 2 is an example of an "operating device". Touch panel 2 is a flat component with an operating surface that can be operated by touch. Touch panel 2, for example, has an electrostatic sensor composed of multiple detection electrodes, which detects the operator's finger touching the operating surface.

[0093] The base 3 is located on the back side of the touch panel 2 and is a flat plate that supports the touch panel 2 and the electromagnetic actuator 150.

[0094] The control device 100-2 controls the vibration of the electromagnetic actuator 150 to generate an action based on the touch operation of the touch panel 2.

[0095] An electromagnetic actuator 150 is disposed between the touch panel 2 and the base 3. The electromagnetic actuator 150 generates vibrations that cause the touch panel 2 to vibrate, thereby transmitting vibrations to the operator's fingers.

[0096] (Equation of motion for damped oscillation of a spring)

[0097] Here, the equation of motion for the damped vibration of a spring is explained.

[0098] When there is viscous resistance proportional to the velocity, the following mathematical formula (1) holds. Where K sp The constant represents the spring constant [N / M]. Additionally, D represents the damping constant [N / (m / s)].

[0099] [Mathematical Expression 1]

[0100]

[0101] In addition, the equation of motion of an object of mass m is represented by the following mathematical formula (2).

[0102] [Mathematical Expression 2]

[0103]

[0104] Here, given the following mathematical expressions (3) and (4), the general solution for 0 < Z < 1 will be obtained by the following mathematical expression (5).

[0105] [Mathematical Expression 3]

[0106]

[0107] [Mathematical Expression 4]

[0108]

[0109] [Mathematical Expression 5]

[0110]

[0111] Furthermore, w is obtained through the following mathematical formulas (6) and (7). d and f d This is called the attenuation of the natural vibration frequency.

[0112] [Mathematical Expression 6]

[0113]

[0114] [Mathematical Expression 7]

[0115]

[0116] (Structure of vibration generating device 10)

[0117] Figure 10 This is a diagram showing the structure of the vibration generating device 10 in another embodiment. Figure 10 In the example shown, the signal processing circuit 120 is used to control the control device 100-2 of the electromagnetic actuator 150. However, the use of the signal processing circuit 120 is not limited to this.

[0118] like Figure 10 As shown, the vibration generating device 10 includes a control device 100-2 and an electromagnetic actuator 150. The control device 100-2 includes a signal processing circuit 120, a drive signal generation unit 130, a drive unit 140, and a frequency measurement circuit 160.

[0119] The electromagnetic actuator 150 includes a movable body 151, a plate-shaped elastic portion 152, a coil 153, and a strain sensor 154. The electromagnetic actuator 150 is configured to generate vibration by supplying current from the drive portion 140 to the coil 153, thereby displacing the movable body 151 supported by the plate-shaped elastic portion 152.

[0120] The signal processing circuit 120 is input with a detection signal detected by a strain sensor 154 (an example of a “sensor”) disposed in the electromagnetic actuator 150. The strain sensor 154 detects the strain of the plate-shaped elastic portion 152 accompanying the displacement of the movable body 151 in the electromagnetic actuator 150, and outputs a detection signal representing the detected strain of the plate-shaped elastic portion 152.

[0121] The signal processing circuit 120 performs various filtering processes on the input detection signal. Specifically, the signal processing circuit 120 includes a low-pass filter 121, a high-pass filter 122, and a phase compensation filter 123.

[0122] Low-pass filter 121 filters the input detection signal to remove high-frequency noise. High-pass filter 122 filters the input detection signal to remove DC components. Phase compensation filter 123 filters the input detection signal to adjust its phase.

[0123] Then, the signal processing circuit 120 outputs the various filtered detection signals to the drive signal generation unit 130.

[0124] The drive signal generation unit 130 generates a main drive signal for vibrating the electromagnetic actuator 150 and supplies the main drive signal to the drive unit 140, thereby causing the drive unit 140 to control the coil 153 of the electromagnetic actuator 150 and cause the electromagnetic actuator 150 to vibrate.

[0125] In addition, the drive signal generation unit 130 generates a secondary drive signal for braking the vibration by shortening the decay period of the vibration of the electromagnetic actuator 150, and supplies the secondary drive signal to the drive unit 140, thereby causing the drive unit 140 to control the coil 153 of the electromagnetic actuator 150 to brake the vibration of the electromagnetic actuator 150.

[0126] At this time, the drive signal generation unit 130 detects the peak timing, valley timing, or zero-crossing timing of the detection signal based on the waveform of the detection signal input from the signal processing circuit 120. Furthermore, the drive signal generation unit 130 can supply a secondary drive signal to the drive unit 140 at an appropriate timing based on the timing of the detected detection signal, effectively braking the vibration of the electromagnetic actuator 150.

[0127] Here, as Figure 10 As shown, the control device 100-2 includes a frequency measurement circuit 160. The frequency measurement circuit 160 measures the resonant frequency of the signal input from the strain sensor 154 to the signal processing circuit 120. Then, the frequency measurement circuit 160 outputs the measured value of the resonant frequency to the subsequent signal processing circuit 120, etc. Thus, the measured value of the resonant frequency determined by the frequency measurement circuit 160 is used by the control device 100-2 to control the braking of the electromagnetic actuator 150. By using the highly accurate measured value of the resonant frequency determined by the frequency measurement circuit 160, the control device 100-2 can perform high-precision braking control of the electromagnetic actuator 150 at an appropriate time corresponding to the actual resonant frequency of the electromagnetic actuator 150.

[0128] Specifically, when the control device 100-2 sets a frequency in the algorithm that is the same as the vibration frequency of the electromagnetic actuator 150, it can correctly output a braking signal that cancels the vibration of the electromagnetic actuator 150, causing the vibration of the electromagnetic actuator 150 to decrease rapidly.

[0129] On the other hand, in the control device 100-2, if the frequency set in the algorithm is different from the vibration frequency of the electromagnetic actuator 150, or if the vibration frequency of the electromagnetic actuator 150 is different from the frequency set in the algorithm due to the change in the clock frequency of the IC, the braking signal that cancels the vibration of the electromagnetic actuator 150 cannot be output correctly. The vibration of the electromagnetic actuator 150 can be gradually attenuated, but it cannot be rapidly attenuated.

[0130] Therefore, the control device 100-2 continuously and accurately measures the vibration frequency of the electromagnetic actuator 150 in the background through the frequency measurement circuit 160, and updates the frequency set in the algorithm to the measured vibration frequency, so that even if the vibration frequency of the electromagnetic actuator 150 is different from the frequency set in the algorithm, the vibration of the electromagnetic actuator 150 can be efficiently attenuated.

[0131] Furthermore, regarding the specific structure for braking the vibration of the electromagnetic actuator 150, the technology disclosed in Japanese Patent Application No. 2023-127739 can be used, for example.

[0132] (Structure of frequency measurement circuit 160)

[0133] Figure 11 This is a diagram illustrating the structure of the frequency measurement circuit 160 in another embodiment. For example... Figure 11 As shown, the frequency measurement circuit 160 includes a filtering unit 161, a zero-crossing detection unit 162, a peak-valley detection unit 163, a selection unit 164, a calculation period determination unit 165, a frequency calculation unit 166, and a frequency update determination unit 167.

[0134] The filtering unit 161 performs filtering processing to remove specific frequency components of the input signal. Specifically, the filtering unit 161 includes a low-pass filter 161A to remove high-frequency noise from the input signal and a high-pass filter 161B to remove the DC component of the input signal.

[0135] The zero-crossing detection unit 162 detects the zero-crossing point based on the signal after filtering by the filtering unit 161.

[0136] The peak and valley detection unit 163 detects the peak points and valley points respectively from the signal after filtering by the filtering unit 161.

[0137] The selection unit 164 selects the zero-crossing point detected by the zero-crossing detection unit 162, or the peak point and valley point detected by the peak-valley detection unit 163, as parameters used in the calculation of the resonant frequency performed by the frequency calculation unit 166.

[0138] The calculation period determination unit 165 determines the calculation period for the measured value of the resonant frequency in the input signal based on the signal filtered by the filtering unit 161 and the peak and valley points detected by the peak and valley detection unit 163. Specifically, the calculation period determination unit 165 determines the calculation period for the measured value of the resonant frequency in the input signal based on the time elapsed until the input signal stops. For example, the calculation period determination unit 165 determines a longer calculation period when the input signal stops slowly, and a shorter calculation period when the input signal stops abruptly.

[0139] The frequency calculation unit 166 calculates the measured value of the resonant frequency of the input signal based on the parameters (zero crossing point, peak point, and valley point) selected by the selection unit 164 and the calculation period determined by the calculation period determination unit 165. For example, the frequency calculation unit 166 calculates the measured value freq of the resonant frequency of the input signal using the following mathematical formula (8). Wherein, t1, t2, ..., tn represent the time of periods 1, 2, ..., n. In addition, N represents the number of periods.

[0140] [Mathematical Expression 8]

[0141]

[0142] The frequency update determination unit 167 determines whether to use the measured values ​​calculated by the frequency calculation unit 166 to update the measured values ​​for braking control of the vibration generating device 10.

[0143] For example, if the measured value calculated by the frequency calculation unit 166 is outside the specified frequency range, the frequency update determination unit 167 considers that the frequency measurement time of the input signal is insufficient due to the sufficient efficiency of the braking control, and the frequency of the input signal is outside the specified frequency range. Therefore, it determines that "the braking force of the braking control of the vibration generating device 10 is sufficient" and determines that the measured value for the braking control of the vibration generating device 10 will not be updated, and the measured value calculated by the frequency calculation unit 166 will not be output to the subsequent signal processing circuit 120.

[0144] Conversely, if the measured value calculated by the frequency calculation unit 166 is within the specified frequency range, the frequency update determination unit 167 considers that the frequency measurement time of the input signal has become sufficient due to insufficient braking control efficiency, and the frequency of the input signal is within the specified frequency range. Therefore, it determines that "the braking force of the braking control of the vibration generating device 10 is insufficient" and determines to update the measured value for the braking control of the vibration generating device 10. The measured value calculated by the frequency calculation unit 166 is then output to the subsequent signal processing circuit 120.

[0145] Furthermore, regarding the specified frequency range, in order to make the above determination with high accuracy, appropriate values ​​are pre-calculated through simulation or other means.

[0146] (Example of resonant frequency calculation (first example))

[0147] Figure 12 This is a diagram illustrating an example (first example) of the resonant frequency calculation performed by the frequency measuring circuit 160 in another embodiment.

[0148] Figure 12This section presents an example of the measured value of the resonant frequency of the input signal calculated by the frequency calculation unit 166 based on the peak and valley points of the input signal, and the measured value of the braking control for the vibration generating device 10 updated by the frequency update determination unit 167.

[0149] Figure 12 (a) represents the waveform of the signal after filtering by the filtering unit 161. Figure 12 (b) represents the peak and valley points detected by the peak and valley detection unit 163. Figure 12 (c) indicates the calculation period determined by the calculation period determination unit 165. Figure 12 (d) represents the measured value of the resonant frequency calculated by the frequency calculation unit 166.

[0150] exist Figure 12 In the example shown in (a), the input signal stops slowly due to the absence of braking control by the vibration generating device 10 or insufficient efficiency of the braking control by the vibration generating device 10. Therefore, as Figure 12 As shown in (c), the calculation period decision unit 165 is based on Figure 12 The peak and trough points of the input signal shown in (b) determine the relatively long calculation period until the input signal stops. Then, as... Figure 12 As shown in (d), the frequency calculation unit 166 will... Figure 12 The calculation period shown in (c) is used as the calculation object to calculate the measured value of the resonant frequency of the input signal.

[0151] Here, as Figure 12 As shown in (d), the measured value of the resonant frequency calculated by the frequency calculation unit 166 is within the specified frequency range (i.e., below the upper limit and above the lower limit). This is because, since the input signal stops slowly, the number of cycles N of the input signal is sufficient, enabling the resonant frequency of the input signal to be measured with high accuracy.

[0152] In this case, the frequency update determination unit 167 determines that "there is no braking control or the braking control efficiency is insufficient," and outputs the measured value calculated by the frequency calculation unit 166 to the signal processing circuit 120, thereby updating the measured value for braking control of the vibration generating device 10. Therefore, the frequency measurement circuit 160 in other embodiments can update the measured value of the resonant frequency for braking control of the vibration generating device 10 with high-precision measured values.

[0153] (Example of resonant frequency calculation (second example))

[0154] Figure 13 This is a diagram illustrating a calculation example (second example) of the resonant frequency of the frequency measurement circuit 160 in another embodiment.

[0155] Figure 13 This refers to the result of the frequency calculation unit 166 calculating the resonant frequency of the input signal based on the peak and valley points of the input signal, and the example of the measured value for braking control of the vibration generating device 10 not being updated by the frequency update determination unit 167.

[0156] Figure 13 (a) represents the waveform of the signal after filtering by the filtering unit 161. Figure 13 (b) represents the peak and valley points detected by the peak and valley detection unit 163. Figure 13 (c) indicates the calculation period determined by the calculation period determination unit 165. Figure 13 (d) represents the measured value of the resonant frequency calculated by the frequency calculation unit 166.

[0157] exist Figure 13 In the example shown in (a), the input signal stops abruptly with the emergency braking of the vibration generating device 10. Therefore, as Figure 13 As shown in (c), the calculation period decision unit 165 is based on Figure 13 The peak and trough points shown in (b) determine a relatively short calculation period until the input signal stops. Then, as... Figure 13 As shown in (d), the frequency calculation unit 166 will... Figure 13 The calculation period shown in (c) is used as the calculation object to calculate the measured value of the resonant frequency of the input signal.

[0158] Here, as Figure 13 As shown in (d), the measured value of the resonant frequency calculated by the frequency calculation unit 166 is outside the specified frequency range (i.e., less than the lower limit). The reason for this is that, since the input signal stops abruptly, the number of cycles N of the input signal becomes insufficient. Furthermore, this is because, when the input signal stops abruptly, equivalent to the damping coefficient D increasing, Z becomes a larger value according to mathematical formula (4), and the frequency measured according to mathematical formulas (6) and (7) becomes relatively smaller.

[0159] In this case, the frequency update determination unit 167 determines that "the braking efficiency is sufficient" and does not output the measured value calculated by the frequency calculation unit 166 to the signal processing circuit 120, thereby not updating the measured value used for braking control of the vibration generating device 10. Therefore, the frequency measurement circuit 160 in other embodiments can suppress the measured value of the resonant frequency used for braking control of the vibration generating device 10 from being updated by inappropriate measured values.

[0160] Furthermore, the frequency calculation unit 166 is not limited to calculating the measured value of the resonant frequency of the input signal based on the peak and valley points of the input signal detected by the peak and valley detection unit 163, but can also calculate the measured value of the resonant frequency of the input signal based on the zero-crossing point of the input signal detected by the zero-crossing detection unit 162.

[0161] As described above, the frequency measuring circuit 160 in other embodiments is a frequency measuring circuit 160 that measures the resonant frequency of the vibration detection signal output from the sensor that detects the vibration of the vibration generating device 10. It includes: a frequency calculation unit 166 that calculates the measured value of the resonant frequency; and a frequency update determination unit 167 that determines, based on the measured value calculated by the frequency calculation unit 166, whether to update the measured value used for braking control of the vibration generating device 10 using the measured value calculated by the frequency calculation unit 166.

[0162] Therefore, the frequency measurement circuit 160 in other embodiments can determine whether to update the measurement value for braking control of the vibration generating device 10 based on the measured value of the resonant frequency, and thus can suppress the measurement value of the resonant frequency for braking control of the vibration generating device 10 from being updated by an inappropriate measurement value.

[0163] In addition, in the frequency measurement circuit 160 of other embodiments, the frequency update determination unit 167 determines that the measurement value for braking control of the vibration generating device 10 will not be updated if the measurement value calculated by the frequency calculation unit 166 is outside the specified frequency range, and determines that the measurement value for braking control of the vibration generating device 10 will be updated if the measurement value calculated by the frequency calculation unit 166 is within the specified frequency range.

[0164] Thus, the frequency measurement circuit 160 in other embodiments can determine whether to update the measured value for braking control of the vibration generating device 10 with a relatively simple structure.

[0165] In addition, the frequency measurement circuit 160 in other embodiments includes a calculation period determination unit 165 that determines the calculation period of the measured value in the input signal based on the time taken until the input signal stops, and the frequency calculation unit 166 calculates the measured value using the calculation period determined by the calculation period determination unit 165 as the calculation object.

[0166] Thus, the frequency measurement circuit 160 in other embodiments can calculate the measurement value during an appropriate calculation period corresponding to the time taken until the input signal stops.

[0167] In addition, the frequency measurement circuit 160 in other embodiments includes a zero-crossing detection unit 162 that detects zero-crossing points in the detection signal, a calculation period determination unit 165 that determines a calculation period corresponding to the time taken until the detection signal stops based on the zero-crossing points detected by the zero-crossing detection unit 162, and a frequency calculation unit 166 that calculates the measured value based on the zero-crossing points detected by the zero-crossing detection unit 162 in the calculation period determined by the calculation period determination unit 165.

[0168] Thus, the frequency measurement circuit 160 in other embodiments can appropriately determine the calculation period of the measured value based on the zero-crossing point in the detection signal, and calculate the measured value with high accuracy.

[0169] In addition, the frequency measurement circuit 160 in other embodiments includes a peak-valley detection unit 163 that detects peak points and valley points in the detection signal, a calculation period determination unit 165 that determines a calculation period corresponding to the time taken until the detection signal stops based on the peak points and valley points detected by the peak-valley detection unit 163, and a frequency calculation unit 166 that calculates the measured value based on the peak points and valley points detected by the peak-valley detection unit 163 in the calculation period determined by the calculation period determination unit 165.

[0170] Thus, the frequency measurement circuit 160 in other embodiments can appropriately determine the calculation period of the measured value based on the peak points and valley points in the detection signal, and calculate the measured value with high accuracy.

[0171] [Comparative Example]

[0172] The following is for reference Figures 14-17 This section describes a comparative example of the waveform of the drive signal of the control device 100-2 using existing control devices and other implementation methods, as well as the braking effect of the electromagnetic actuator.

[0173] Furthermore, the control device 100 used in this comparative example has both the functions of the control device 100 of one embodiment (i.e., the function of automatically changing the filter coefficients according to the frequency of the input signal) and the functions of the control device 100-2 of another embodiment (i.e., the function of high-precision resonant frequency measurement).

[0174] (An example of the main drive signal and the secondary drive signal)

[0175] Figure 14 This is a diagram showing a comparison of the main drive signal and the auxiliary drive signal output from the control device.

[0176] like Figure 14As shown, both the existing control device and the control device 100 of the embodiment output a secondary drive signal for braking the vibration of the electromagnetic actuator after outputting a main drive signal for causing the electromagnetic actuator to vibrate.

[0177] Figure 15 This is a diagram showing a comparative example of the secondary drive signal output from the control device. Figure 15 It is an enlarged representation Figure 14 The diagram shows the secondary drive signals. Furthermore, in... Figure 15 The example also illustrates the secondary drive signal of the electromagnetic actuator when its vibration frequency shifts to a 5% lower value. For example... Figure 15 As shown, the waveform of the secondary drive signal to the electromagnetic actuator (dashed line in the figure) output from the control device 100 of the embodiment, when the vibration frequency of the electromagnetic actuator is shifted to a lower value by 5%, is shifted on the time axis relative to the waveform of the secondary drive signal output from the conventional control device (solid line in the figure), and the time width changes.

[0178] This is because, when the vibration frequency of the electromagnetic actuator shifts to a lower value by 5%, the secondary drive signal output from the control device 100, as described in the other embodiments above, performs a high-precision measurement of the resonant frequency, and as described in one embodiment above, automatically changes the filter coefficients according to the frequency of the input signal.

[0179] Figure 16 This is a diagram showing the vibration waveform of the electromagnetic actuator when the vibration of the electromagnetic actuator is braked according to the auxiliary drive signal output from the existing control device. Furthermore, in Figure 16 The example illustrates the vibration waveform of an electromagnetic actuator when its vibration frequency shifts to a 5% lower value. Furthermore, in... Figure 16 In the diagram, the solid line represents the vibration waveform of the electromagnetic actuator 150 when appropriate braking is applied to the electromagnetic actuator 150 which has no vibration frequency offset, and the dashed line represents the vibration waveform of the electromagnetic actuator 150 when braking is applied to the electromagnetic actuator 150 whose vibration frequency is offset to a lower value by 5% according to the auxiliary drive signal output from the existing control device.

[0180] Because the existing control device did not perform high-precision resonant frequency measurement, the filter coefficients were not properly adjusted. Therefore, as... Figure 16 As shown, when the vibration frequency of the electromagnetic actuator shifts to a lower value by 5%, the auxiliary drive signal output from the existing control device (refer to...) Figure 15 When braking the vibration of the electromagnetic actuator (with the solid line), it is impossible to apply braking to the electromagnetic actuator at an appropriate timing and with an appropriate time amplitude, and the residual vibration of the electromagnetic actuator cannot be brought to a convergence in a short time.

[0181] Figure 17 This is a graph showing the vibration waveform of the electromagnetic actuator 150 when the vibration of the electromagnetic actuator 150 is braked by the auxiliary drive signal output from the control device 100 of the embodiment. Furthermore, in Figure 17 The diagram illustrates the vibration waveform of the electromagnetic actuator 150 when its vibration frequency shifts to a 5% lower value. Furthermore, in... Figure 17 In the diagram, the solid line represents the vibration waveform of the electromagnetic actuator 150 when appropriate braking is applied to the electromagnetic actuator 150 which has no vibration frequency deviation, and the dashed line represents the vibration waveform of the electromagnetic actuator 150 when braking is applied to the electromagnetic actuator 150 whose vibration frequency has shifted to a lower value by 5% according to the auxiliary drive signal output from the control device 100 of the embodiment.

[0182] The control device 100 of the embodiment is capable of high-precision measurement of the resonant frequency and appropriate adjustment of the filter coefficients. Therefore, as Figure 17 As shown, when the vibration frequency of the electromagnetic actuator 150 shifts to a lower value by 5%, the auxiliary drive signal output from the control device 100 of the embodiment (refer to...) Figure 15 When the vibration of the electromagnetic actuator 150 is braked by the dashed line, the electromagnetic actuator 150 can be braked with an appropriate timing and an appropriate time width, so that the residual vibration of the electromagnetic actuator 150 can be converged in a short time.

[0183] As described above, the control device 100 according to the embodiment performs high-precision measurement of the resonant frequency and automatically changes the filter coefficient according to the frequency of the input signal. Therefore, the waveform of the auxiliary drive signal applied to the electromagnetic actuator 150 can be appropriately adjusted, thereby improving the braking effect of the electromagnetic actuator 150.

[0184] Therefore, for example, the waveform of the secondary drive signal output from a certain control device is similar to that from... Figure 15 When the waveform of the auxiliary drive signal output by the control device 100 in the illustrated embodiment is similarly adjusted, or as... Figure 17 As shown, if the residual vibration of the electromagnetic actuator converges within a short period of time based on the secondary drive signal output from a certain control device, it can be easily inferred that the control device is performing the same processing as the control device 100 of one embodiment (i.e., the processing of automatically changing the filter coefficients according to the frequency of the input signal) and the same processing as the control device 100-2 of other embodiments (i.e., the processing of high-precision resonant frequency measurement).

[0185] Furthermore, the control device 100 according to the embodiment is able to apply braking to the electromagnetic actuator 150 at a predetermined timing (valley timing, top timing, or cross timing) based on the input signal, regardless of the frequency of the input signal.

[0186] Therefore, for example, if the auxiliary drive signal output from a certain control device can always apply braking to the electromagnetic actuator 150 at a predetermined timing (valley timing, top timing, or cross timing) based on the input signal, regardless of the frequency of the input signal (the detection signal of the strain sensor 154), the control device can also be easily presumed to perform the same processing as the control device 100 of one embodiment (i.e., the processing of automatically changing the filter coefficients according to the frequency of the input signal) and the same processing as the control device 100-2 of other embodiments (i.e., the processing of high-precision resonant frequency measurement).

[0187] Furthermore, the control device 100 according to the embodiment can accurately measure the resonant frequency of the input signal, and therefore can adjust the pulse width of one cycle of the auxiliary drive signal used to apply braking to the electromagnetic actuator 150 to an appropriate pulse width based on the resonant frequency of the input signal.

[0188] Therefore, for example, if the secondary drive signal output from a certain control device is a signal whose pulse width is adjusted by one cycle according to the resonant frequency of the input signal, it can be easily inferred that the control device is a device that performs the same processing as the control device 100-2 in other embodiments (i.e., high-precision resonant frequency measurement processing).

[0189] The above describes one embodiment of the present invention in detail, but the present invention is not limited to these embodiments. Various modifications or alterations can be made within the scope of the spirit of the present invention as set forth in the claims.

[0190] This international application claims priority to Japanese Patent Application Nos. 2024-024558 and 2024-024559, filed on February 21, 2024, the entire contents of which are incorporated herein by reference.

[0191] Explanation of reference numerals in the attached figures

[0192] 10 Vibration Generating Device

[0193] 100, 100-2 control devices

[0194] 120 signal processing circuit

[0195] 121 low-pass filter

[0196] 122 high-pass filter

[0197] 123 phase compensation filter

[0198] 124 Filter Coefficient Change Section

[0199] 124A Computing Unit

[0200] 124B Selection Section

[0201] 124C memory

[0202] 130 drive signal generation unit

[0203] 140 Drive Unit

[0204] 150 electromagnetic actuator

[0205] 151 movable bodies

[0206] 152 Plate-shaped elastic part

[0207] 153 coil

[0208] 154 Strain Sensor (Sensor)

[0209] 160 Frequency Measurement Circuit

[0210] 161 Filter Section

[0211] 161A low-pass filter

[0212] 161B High-Pass Filter

[0213] 162 Zero-crossing Detection Department

[0214] Peak and Valley Testing Department 163

[0215] 164 Selection Department

[0216] 165 Calculation Period Decision Department

[0217] 166 Frequency Calculation Unit

[0218] 167 Frequency Update Judgment Unit.

Claims

1. A signal processing circuit, characterized in that, have: A filter is used to filter input signals. The filter coefficient changing unit automatically changes the filter coefficients according to the frequency of the input signal.

2. The signal processing circuit according to claim 1, characterized in that, The filter coefficient changing unit includes a calculation unit that calculates the changed coefficients using a polynomial function.

3. The signal processing circuit according to claim 2, characterized in that, The calculation unit calculates the modified coefficients using the first-order polynomial function.

4. The signal processing circuit according to claim 2, characterized in that, The calculation unit calculates the modified coefficients using the second-order polynomial function.

5. The signal processing circuit according to claim 1, characterized in that, The filter coefficient changing unit has a selection unit that selects, from a plurality of coefficients stored in a memory, the coefficient corresponding to the frequency of the input signal as the changed coefficient.

6. The signal processing circuit according to any one of claims 1 to 5, characterized in that, The signal processing circuit includes multiple filters. The filter coefficient changing unit changes the coefficients of each of the multiple filters simultaneously.

7. A control device that controls an actuator that applies vibration to an operating device based on the operation of the operating device, characterized in that, The control device includes the signal processing circuit as described in claim 1. The input signal is a signal obtained by a sensor based on the vibration of the actuator.

8. The control device according to claim 7, characterized in that, The signal processing circuit includes a drive signal generation unit that generates a drive signal for braking the vibration of the actuator based on the input signal after the filter processing. The drive signal generation unit automatically changes the coefficients of the filter according to the frequency of the input signal to generate a drive signal that can brake the vibration of the actuator at a predetermined timing regardless of the frequency of the input signal.

9. The control device according to claim 8, characterized in that, The specified timing is based on the peak timing, valley timing, or zero-crossing timing of the input signal.

Images