Flution detection device and seat device

Abstract

The invention provides a fluctuation detection device and a seat device, which can optimally control the passband of a variable filter according to the driving state of a motor by using a linear relation formula for deriving the frequency of fluctuation current based on the fluctuation current and voltage between motor terminals, and can detect fluctuation pulse with high precision. A fluctuation detection device (100) is provided with: a fluctuation current detection unit (112, 24) that detects a fluctuation current generated when a motor (23) is driven; a motor voltage detection unit (111) that detects a voltage between terminals of the motor; a variable filter (130) through which a component of a predetermined frequency band in the ripple current detected by the ripple current detection unit passes; and a frequency adjustment unit (161) that uses a linear relational expression that derives the frequency of the ripple current on the basis of the ripple current detected by the ripple current detection unit and the inter-terminal voltage detected by the motor voltage detection unit to adjust a prescribed frequency band of the variable filter so as to include the derived frequency of the ripple current.

Description

Technical Field

[0001] The present disclosure relates to a wave detection device and a seat device. Background Art

[0002] Conventionally, there is a fluctuation detection device that detects fluctuations superimposed on a waveform of a motor, and is characterized by comprising an AD converter that oversamples analog data of the waveform at a frequency higher than the frequency of the fluctuation and converts the analog data into digital data, a digital filter that is input with the digital data and has a variable filter characteristic, and a filter characteristic control mechanism that changes a filter coefficient of the digital filter so that the filter characteristic becomes an optimal characteristic for detecting the fluctuation. The low-pass filter of the digital filter has a linear phase characteristic or a substantially linear phase characteristic, and phase distortion is suppressed (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-207236 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] However, conventional fluctuation detection devices do not focus on the linearity of the fluctuation current, the voltage between the motor terminals, and the frequency of the fluctuation current.

[0008] Therefore, the object of the present invention is to provide a fluctuation detection device and a seat device that can use a linear relationship of the frequency of the fluctuation current derived based on the fluctuation current and the voltage between the motor terminals to optimally control the passband of the variable filter according to the driving state of the motor and detect the fluctuation pulse with high precision.

[0009] Means for solving technical problems

[0010] The fluctuation detection device of the embodiment of the present disclosure comprises: a fluctuation current detection unit, which detects the fluctuation current generated when the motor is driven; a motor voltage detection unit, which detects the voltage between the terminals of the above-mentioned motor; a variable filter, which allows the component of a specified frequency band in the fluctuation current detected by the above-mentioned fluctuation current detection unit to pass; and a frequency adjustment unit, which uses a linear relationship based on the fluctuation current detected by the above-mentioned fluctuation current detection unit and the voltage between the terminals detected by the above-mentioned motor voltage detection unit to derive the frequency of the above-mentioned fluctuation current, and adjusts the above-mentioned specified frequency band of the above-mentioned variable filter so that the above-mentioned specified frequency band includes the derived frequency of the above-mentioned fluctuation current.

[0011] Effects of the Invention

[0012] A fluctuation detection device and a seat device can be provided, which can detect fluctuation pulses with high accuracy by optimally controlling the passband of a variable filter according to the driving state of a motor by using a linear relationship of the frequency of a fluctuation current derived from the fluctuation current and the voltage between motor terminals. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram showing an example of a seat device mounted on a vehicle.

[0014] Figure 2 This is a diagram showing an example of a circuit configuration of a fluctuation detection device.

[0015] Figure 3 This is a diagram showing experimental results showing the relationship between a ripple current and the frequency of the ripple current.

[0016] Figure 4 This is a graph showing the experimental results of the relationship between the ripple current, the frequency of the ripple current, and the ambient temperature.

[0017] Figure 5A This is a diagram showing an example of the detection result of the fluctuation pulse.

[0018] Figure 5B This is a diagram showing an example of the detection result of the fluctuation pulse. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of a wave detection device and a seat device to which the present disclosure is applied will be described.

[0020] <Implementation Method 1>

[0021] Figure 1 1 is a diagram showing an example of a seat device 10 mounted on a vehicle 1. The seat device 10 includes a seat 20, a fluctuation detection device 100, and a drive control unit 50. The seat 20 has a seat portion 21, a backrest portion 22, and motors 23A and 23B. The motor 23A is a DC (Direct Current) motor that moves the seat portion 21 forward and backward or up and down, and the motor 23B is a DC motor that changes the angle of the backrest portion 22. The voltage and current between the terminals of the motors 23A and 23B are input to the fluctuation detection device 100.

[0022] The fluctuation detection device 100 detects the fluctuation current of the motors 23A and 23B and outputs it to the drive control unit 50. The drive control unit 50 is connected to a switch (not shown) for adjusting the seat 21 or the backrest 22. When the switch is operated, the seat 21 is moved forward and backward or up and down or the angle of the backrest 22 is controlled while detecting the rotation angle of the motor 23A or 23B based on the fluctuation current detected by the fluctuation detection device 100.

[0023] Hereinafter, the motor 23A or 23B will be described as the motor 23 without distinguishing between them. The motor 23 is adjusted to adjust the position, angle, etc. of the seat 20. The adjustment of the position, angle, etc. of the seat 20 is not limited to the forward and backward adjustment or the up and down adjustment of the seat 21 and the adjustment of the angle of the backrest 22, and other directions, angles, etc. may also be adjusted.

[0024] <Circuit Configuration of Fluctuation Detection Device 100>

[0025] Figure 2 FIG. 1 is a diagram showing an example of a circuit configuration of the fluctuation detection device 100. Figure 2 , in addition to the fluctuation detection device 100 , a motor 23 , a resistor 24 , and a drive control unit 50 are shown. The resistor 24 is connected to one of two terminals of the motor 23 , and is a sense resistor used to detect the current of the motor 23 .

[0026] The fluctuation detection device 100 includes a voltage detection unit 111, a current detection unit 112, a filter 121, a filter 122, a variable filter 130, a filter 140, a fluctuation pulse generation unit 150, an MCU (Micro Controller) 160, and a temperature sensor 170. The MCU 160 has a frequency adjustment unit 161 and a memory 162. The filter 122, the variable filter 130, and the filter 140 constitute a high-order filter.

[0027] The voltage detection unit 111 is an example of a motor voltage detection unit. The current detection unit 112 and the resistor 24 are examples of a fluctuating current detection unit. The filter 121 is an example of a first filter. The filter 122 is an example of a second filter.

[0028] The voltage detection unit 111 is connected to two terminals of the motor 23, detects the voltage between the terminals of the motor 23, and outputs the voltage to the filter 121. As the voltage detection unit 111, for example, a voltage detection circuit including an amplifier can be used.

[0029] The current detection unit 112 receives the voltage between both ends of the resistor 24 as a voltage indicating the current (ripple current) of the motor 23 , and outputs the voltage indicating the ripple current to the MCU 160 and the filter 122 .

[0030] The filter 121 is an LPF (Low Pass Filter). The filter 121 is connected to the output side of the voltage detection unit 111, removes high-frequency noise and the like contained in the inter-terminal voltage of the motor 23 input from the voltage detection unit 111, and outputs it. The inter-terminal voltage output by the filter 121 is converted into a digital value of the inter-terminal voltage by an A / D (Analog to Digital) converter (not shown) and input to the MCU 160.

[0031] The filter 122 is an LPF, removes high-frequency noise and the like included in the voltage input from the current detection unit 112 , and outputs the voltage to the variable filter 130 .

[0032] The variable filter 130 is a BPF (Band Pass Filter) whose passband is adjusted by the frequency adjustment unit 161 of the MCU 160. The passband of the variable filter 130 is an example of a predetermined frequency band. The variable filter 130 outputs the passband component of the voltage after passing through the filter 122 to the filter 140.

[0033] The filter 140 is a HPF (High Pass Filter) and removes low-frequency noise and the like included in the voltage after passing through the variable filter 130 , and outputs the voltage to the fluctuation pulse generator 150 .

[0034] The ripple pulse generator 150 performs a ripple generation process for generating (detecting) ripples included in a voltage representing the current input from the filter 140, converts the ripples into pulses (ripple pulses), and outputs the pulses to the MCU 160. The ripple pulses are pulses representing the current value of the ripple current.

[0035] MCU160 is implemented by a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), an input / output interface, and an internal bus. MCU160 has a frequency adjustment unit 161 and a memory 162, and performs processing for detecting a fluctuating current. As an example of processing for detecting a fluctuating current, the voltage representing the fluctuating current input from the current detection unit 112 is calculated as a current value of the fluctuating current using a pre-set voltage / current conversion table stored in the memory 162. The frequency adjustment unit 161 represents the function (function) of the program executed by MCU160 as a functional block. The memory 162 represents the memory of MCU160 as a functional block.

[0036] The frequency adjustment unit 161 uses a linear relationship expression for deriving the frequency of the fluctuating current based on the current value of the fluctuating current detected by the fluctuating current detection unit (the current detection unit 112 and the resistor 24) and the voltage value of the inter-terminal voltage detected by the voltage detection unit 111 and indicating the voltage after passing through the filter 121, and adjusts the passband of the variable filter 130 so that it includes the derived frequency of the fluctuating current. The linear relationship expression for deriving the frequency of the fluctuating current based on the current value of the fluctuating current and the voltage value of the inter-terminal voltage is used. Figure 3 and Figure 4 This will be described later.

[0037] The memory 162 stores programs and data used in the process for detecting the ripple current by the MCU 160 , data generated in the process, etc. The memory 162 stores a linear relationship used by the frequency adjustment unit 161 to adjust the passband of the variable filter 130 and other data.

[0038] The temperature sensor 170 is a temperature sensor that detects the ambient temperature of the motor 23. The temperature sensor 170 outputs data indicating the detected temperature to the MCU 160.

[0039] <Relationship between Fluctuating Current and Frequency of Fluctuating Current>

[0040] Figure 3 2 is a graph showing experimental results showing the relationship between a fluctuating current and the frequency of the fluctuating current. Figure 3 In FIG. 1 , the horizontal axis represents the fluctuating current Ir, and the vertical axis represents the frequency fr of the fluctuating current. The frequency fr of the fluctuating current is the frequency of the fluctuating pulses included in the fluctuating current.

[0041] The load acting on the motor 23 used for adjusting the seat 20 is larger when the person is seated in the seat 20 than when the person is not seated, so the fluctuation current Ir changes more. If the fluctuation current Ir changes, the torque output by the motor 23 changes, and the frequency fr of the fluctuation current changes. Therefore, the fluctuation current Ir and the frequency fr of the fluctuation current change between the state where the person is seated in the seat 20 and the state where the person is not seated.

[0042] Figure 3 The experimental results shown are obtained by placing a heavy object on the seat 20 to simulate a state where a person sits on the seat 20, and measuring the fluctuating current Ir and the frequency fr of the fluctuating current while changing the weight of the heavy object. In addition, the state where a person does not sit on the seat 20 is a state where no heavy object is placed on the seat 20.

[0043] exist Figure 3 In FIG. 1 , the voltage between the terminals applied to the motor 23 is V1, and the fluctuating current Ir and the frequency fr of the fluctuating current are shown when there is a seated person (black squares (■)), and the voltage between the terminals applied to the motor 23 is V1, and the fluctuating current Ir and the frequency fr of the fluctuating current are shown when there is no seated person (white squares (□)). Figure 3 In FIG. 1 , the voltage between the terminals applied to the motor 23 is V2, and the fluctuating current Ir and the frequency fr of the fluctuating current are shown (black triangle (▲)) when there is a seated person, and the voltage between the terminals applied to the motor 23 is V2, and the fluctuating current Ir and the frequency fr of the fluctuating current are shown (white triangle (△)) when there is no seated person. Figure 3In this case, the voltage between terminals applied to the motor 23 is V3, the fluctuating current Ir and the frequency fr of the fluctuating current in the case of an occupant (black circle (●)), and the voltage between terminals applied to the motor 23 is V3, the fluctuating current Ir and the frequency fr of the fluctuating current in the case of no occupant (white circle (○)) are shown. In addition, the voltage between terminals of the motor 23 is V1 < V2 < V3. As an example, V1 = 9V, V2 = 13.5V, and V3 = 16V.

[0044] In Figure 3 this case, it can be seen that the characteristics in the case of a voltage between terminals of V1 and an occupant are distributed along the straight line (1), and the characteristics in the case of a voltage between terminals of V1 and no occupant are also distributed along the straight line (1). The straight line (1) is, as an example, a straight line obtained by fitting using the least squares method. When the voltage between terminals is V1, in the case of an occupant, compared with the case of no occupant, the fluctuating current Ir is larger, the change amount of the fluctuating current Ir is also larger, and the frequency fr of the fluctuating current becomes lower.

[0045] In addition, it can be seen that the characteristics in the case of a voltage between terminals of V2 and an occupant are distributed along the straight line (2), and the characteristics in the case of a voltage between terminals of V2 and no occupant are also distributed along the straight line (2). The straight line (2) is, as an example, a straight line obtained by fitting using the least squares method. When the voltage between terminals is V2, in the case of an occupant, compared with the case of no occupant, the fluctuating current Ir is larger, the change amount of the fluctuating current Ir is also larger, and the frequency fr of the fluctuating current becomes lower. This is the same trend as when the voltage between terminals is V1.

[0046] In addition, it can be seen that the characteristics in the case of a voltage between terminals of V3 and an occupant are distributed along the straight line (3), and the characteristics in the case of a voltage between terminals of V3 and no occupant are also distributed along the straight line (3). The straight line (3) is, as an example, a straight line obtained by fitting using the least squares method. When the voltage between terminals is V3, in the case of an occupant, compared with the case of no occupant, the fluctuating current Ir is larger, the change amount of the fluctuating current Ir is also larger, and the frequency fr of the fluctuating current becomes lower. This is the same trend as when the voltage between terminals is V1 and V2. In addition, the method for obtaining the straight lines (1), (2), and (3) is not limited to the least squares method, and other methods can also be used.

[0047] As described above, in Figure 3 this case, it can be seen that when the voltage between terminals is constant, the fluctuating current Ir and the frequency fr of the fluctuating current have a linear relationship. In addition, although the intercept values of the frequency fr of the fluctuating current are different, the slopes of the straight lines (1), (2), and (3) (the ratio (Δfr / ΔIr) of the change amount Δfr of the frequency fr of the fluctuating current to the change amount Δir of the fluctuating current Ir) are substantially the same.

[0048] The linear relationship between the ripple current Ir and the frequency fr of the ripple current can be expressed by the following equation (1).

[0049] fr=α×Ir+β×Vm (1)

[0050] Here, α is the ratio of the change Δfr of the frequency fr of the fluctuating current to the change ΔIr of the fluctuating current Ir, and is α=Δfr / ΔIr. Also, β is the ratio of the change Δfr of the frequency fr of the fluctuating current to the change ΔVm of the terminal voltage Vm of the motor 23, and is β=Δfr / ΔVm.

[0051] As shown in formula (1), the frequency fr of the fluctuating current can be derived based on the fluctuating current Ir and the inter-terminal voltage Vm. That is, formula (1) is an example of a linear relationship formula for deriving the frequency fr of the fluctuating current based on the fluctuating current Ir and the inter-terminal voltage Vm. In formula (1), since β×Vm, which is the frequency fr of the fluctuating current, can be expressed by a value including the inter-terminal voltage Vm as a parameter, formula (1) can derive the frequency fr of the fluctuating current corresponding to various inter-terminal voltages Vm.

[0052] In addition, as an example, α satisfies -200<α<-100, and more preferably satisfies -160<α<-120. As an example, according to Figure 3 The optimal value of α is -140, which is the ratio of the change in the frequency of the fluctuating current to the change in the fluctuating current. In addition, β is 50<β<250, and more preferably satisfies 100<β<150. As an example, according to Figure 3 The optimal value of β is 130, which is the ratio of the change in the frequency of the ripple current to the change in the voltage between the terminals. However, since α and β vary according to the inherent motor resistance value and motor power generation coefficient of the motor 23, the optimal value varies depending on the motor used.

[0053] Furthermore, as described above, the fluctuating current Ir and the frequency fr of the fluctuating current have a linear relationship, and it is understood that the fluctuating current Ir and the frequency fr of the fluctuating current vary due to the weight of the heavy object.

[0054] Here, a comparative fluctuation detection device is studied in which the variable filter 130 is not included and the fluctuation current that has passed through the filter 122 is directly input to the filter 140. Figure 3When the frequency fr of the fluctuating current varies as shown, in a comparative fluctuation detection device that does not include the variable filter 130, in a high-order bandpass filter implemented by the filter 122 as an LPF and the filter 140 as an HPF, if the frequency fr of the fluctuating current varies, the noise is not completely removed, and the fluctuation pulse is missing (missed detection of the fluctuation) or the fluctuation pulse is erroneously detected, and there is a possibility that the fluctuation pulse cannot be detected with good accuracy.

[0055] Therefore, in the fluctuation detection device 100 of the embodiment, the passband of the variable filter 130 is adjusted according to the frequency fr of the fluctuation current calculated based on formula (1), thereby following the frequency fr of the fluctuation current and removing the noise, suppressing the missing of the fluctuation pulse (missed detection of the fluctuation) and the erroneous detection of the fluctuation pulse, and detecting the fluctuation pulse with high precision.

[0056] Therefore, the frequency adjustment unit 161 only needs to substitute the value of the fluctuating current obtained based on the fluctuating pulse and the inter-terminal voltage Vm into the formula (1) to obtain the frequency fr of the fluctuating current, and adjust the passband of the variable filter 130 so that the frequency fr of the fluctuating current is included in the passband of the variable filter 130. The frequency adjustment unit 161 outputs a variable clock corresponding to the obtained frequency fr of the fluctuating current to the variable filter 130 to adjust the passband. The frequency fr of the fluctuating current is included in the passband of the variable filter 130 so as to be suitable for the driving state of the motor 23. The data of the expression (1) is stored in the memory 162, and the frequency adjustment unit 161 only needs to read the data of the expression (1) from the memory 162 and use it for calculation.

[0057] <Relationship between Fluctuating Current, Fluctuating Current Frequency, and Ambient Temperature>

[0058] Figure 4 This is a diagram showing experimental results showing the relationship between the ripple current, the frequency of the ripple current, and the ambient temperature. Figure 4 The results obtained by changing the ambient temperature are shown in Figure 3 The same is true for the relationship between the fluctuating current and the frequency of the fluctuating current. Figure 4 (A)~ Figure 4 (C) Figure 3 Similarly, straight lines (1) to (3) are shown. Straight lines (1) to (3) are straight lines obtained by fitting when the voltages between the terminals are V1, V2, and V3 and there is a seated person. For example, V1 = 9V, V2 = 13.5V, and V3 = 16V.

[0059] exist Figure 4 (A) shows the relationship between the ripple current and the frequency of the ripple current obtained when the ambient temperature is low. The ambient temperature is the temperature of the environment where the ripple detection device 100 is arranged, and can be understood as the room temperature of the vehicle 1 .

[0060] The low temperature is a temperature lower than 25°C, which is an example of a reference temperature, and is -20°C, for example. Figure 4 (B) shows the relationship between the fluctuating current and the frequency of the fluctuating current obtained when the ambient temperature is the reference temperature. The reference temperature is 25°C as an example. 25°C is an example of a predetermined reference temperature. Figure 4 (C) shows the relationship between the ripple current and the frequency of the ripple current obtained when the ambient temperature is high. The high temperature is a temperature higher than 25°C as an example of a reference temperature, and is 80°C as an example.

[0061] like Figure 4 (A)~ Figure 4 As shown in (C), under any ambient temperature, Figure 3 Similarly, the fluctuating current Ir and the frequency fr of the fluctuating current show a linear relationship. In addition, the relationship between the slope α in equation (1) and the temperature T is obtained. Figure 4 The temperature T is the temperature obtained by subtracting the reference temperature (25°C) from the ambient temperature t, and is T = t - 25°C.

[0062] like Figure 4 As shown in (D), since the slope α of the low temperature (-20℃), the reference temperature (25℃) and the high temperature (80℃) is linear with respect to the temperature T, the frequency fr of the fluctuating current can be expressed by the following formula (2) based on the fluctuating current Ir, the terminal voltage Vm and the temperature T.

[0063] fr=α×Ir×K+β×Vm (2)

[0064] Here, K is a variable temperature coefficient represented by the following formula (3).

[0065] K=1-γ×T (3)

[0066] In the formula (3), γ is a predetermined temperature coefficient, which is the absolute value of the ratio of the change amount Δα of the slope α to the change amount Δt of the ambient temperature t.

[0067] Therefore, the frequency adjustment unit 161 only needs to find the temperature T based on the ambient temperature t detected by the temperature sensor 170, substitute the temperature T into the formula (3) to find the variable temperature coefficient K, and substitute the value of the fluctuating current found based on the fluctuating pulse, the terminal voltage Vm and the variable temperature coefficient K into the formula (2) to find the frequency fr of the fluctuating current. In addition, the frequency adjustment unit 161 only needs to adjust the passband of the variable filter 130 so that the frequency fr of the fluctuating current is included in the passband of the variable filter 130. The frequency adjustment unit 161 outputs a variable clock corresponding to the found frequency fr of the fluctuating current to the variable filter 130 to adjust the passband. The frequency fr of the fluctuating current is included in the passband of the variable filter 130 so as to be suitable for the driving state of the motor 23. The frequency adjustment unit 161 only needs to read the data representing the formulas (2) and (3) from the memory 162 and use them for calculation.

[0068] In addition, as an example, γ more preferably satisfies 0.2<γ<0.5. As an example, according to Figure 4 In (D), the optimum value of γ is 0.34, which is the absolute value of the ratio of the change in slope to the change in ambient temperature.

[0069] <Results of detection of fluctuation pulse>

[0070] Figure 5A and Figure 5B FIG. 1 is a diagram showing an example of the detection result of the fluctuation pulse. Figure 5A An example of the detection result of the fluctuation pulse obtained by the fluctuation detection device 100 is shown in FIG. Figure 5B An example of the detection result of the fluctuation pulse obtained by the fluctuation detection device for comparison is shown in . The fluctuation detection device for comparison does not include the variable filter 130, and the filter 140 as the HPF is directly connected to the output side of the filter 122 as the LPF.

[0071] exist Figure 5A and Figure 5B In FIG. 1 , the lower section shows the ripple current input to the ripple pulse generating section 150 , and the upper section shows the ripple pulse output from the ripple pulse generating section 150 .

[0072] exist Figure 5A There is no missing (missing detection) or false detection in the wave pulse shown in the upper section, and the wave pulse can be detected with high accuracy at a certain interval. Therefore, if the wave detection device 100 of the embodiment is used, the rotation position of the motor 23 can be detected with high accuracy regardless of the load of the motor 23, and the seat 20 can be adjusted correctly.

[0073] On the other hand, Figure 5BIn the wave pulse shown in the upper part of , a missing (missed detection) or misdetection occurs in the portion surrounded by the dotted square, and the wave pulse cannot be detected at a certain interval. Therefore, if a wave detection device for comparison is used, the rotation position of the motor 23 cannot be detected with high accuracy, and the seat 20 cannot be adjusted correctly.

[0074] <Effect>

[0075] The fluctuation detection device 100 includes: a current detection unit 112 and a resistor 24 for detecting a fluctuation current generated when the motor 23 is driven; a voltage detection unit 111 for detecting a voltage Vm between terminals of the motor 23; a variable filter 130 for passing a component of a predetermined frequency band in the fluctuation current detected by the current detection unit 112 and the resistor 24; and a frequency adjustment unit 161 for adjusting the predetermined frequency band of the variable filter 130 so as to include the derived frequency of the fluctuation current using a linear relationship equation for deriving the frequency of the fluctuation current based on the fluctuation current detected by the current detection unit 112 and the resistor 24 and the voltage Vm between terminals detected by the voltage detection unit 111. Therefore, the frequency of the fluctuation current can be derived based on the linear relationship equation based on the fluctuation current and the voltage Vm between terminals, and the predetermined frequency band of the variable filter 130 can be adjusted based on the frequency of the fluctuation current, thereby suppressing the missing of fluctuation pulses (missed detection of fluctuations) and erroneous detection of fluctuation pulses.

[0076] Therefore, a fluctuation detection device 100 can be provided, which uses a linear relationship of the frequency fr of the fluctuation current derived based on the fluctuation current Ir and the voltage Vm between the motor terminals, optimally controls the passband of the variable filter 130 according to the driving state of the motor 23, and can detect the fluctuation pulse with high accuracy.

[0077] In addition, the linear relationship is represented by equation (1). The equation (1) shown here is the same as the above-mentioned equation (1).

[0078] fr=α×Ir+β×Vm (1)

[0079] Wherein, Ir is the fluctuating current, fr is the frequency of the fluctuating current, α is the ratio of the change Δfr of the fluctuating current frequency fr to the change ΔIr of the fluctuating current Ir (Δfr / ΔIr), and β is the ratio of the change Δfr of the fluctuating current frequency fr to the change ΔVm of the terminal voltage Vm (Δfr / ΔVm).

[0080] Therefore, it is possible to provide the fluctuation detection device 100 which can adjust the passband of the variable filter 130 by utilizing the linearity between the fluctuation current Ir and the frequency fr of the fluctuation current, thereby achieving high-speed processing and detecting the fluctuation pulse with high accuracy.

[0081] In addition, the fluctuation detection device 100 is further provided with a temperature sensor 170 for detecting the ambient temperature of the motor 23. The frequency adjustment unit 161 uses a linear relationship between the fluctuation current detected by the current detection unit 112 and the resistor 24, the terminal voltage Vm detected by the voltage detection unit 111, and the ambient temperature detected by the temperature sensor 170 to adjust the predetermined frequency band of the variable filter 130 so that it includes the derived frequency of the fluctuation current, and the linear relationship is represented by the following equation (2). The equation (2) shown here is the same as the above equation (2).

[0082] fr=α×Ir×K+β×Vm (2)

[0083] Here, Ir is the fluctuating current, fr is the frequency of the fluctuating current, α is the ratio of the change Δfr of the frequency fr of the fluctuating current to the change ΔIr of the fluctuating current Ir (Δfr / ΔIr), K is the variable temperature coefficient represented by the following equation (3), and β is the ratio of the change Δfr of the frequency fr of the fluctuating current to the change ΔVm of the inter-terminal voltage Vm (Δfr / ΔVm). The equation (3) shown here is the same as the above equation (3).

[0084] K=1-γ×T (3)

[0085] In the formula (3), γ is a predetermined temperature coefficient, and T is a temperature obtained by subtracting a predetermined reference temperature from the ambient temperature t of the motor 23 detected by the temperature sensor 170 .

[0086] Therefore, a fluctuation detection device 100 can be provided, which adjusts the passband of the variable filter 130 by utilizing the linearity between the fluctuation current Ir and the variable temperature coefficient K and the frequency fr of the fluctuation current, taking into account the ambient temperature t of the motor 23 detected by the temperature sensor 170, and can achieve high-speed processing while taking into account the ambient temperature t, and can detect fluctuation pulses with high accuracy.

[0087] In addition, the fluctuation detection device 100 further includes a memory 162 that stores data representing the linear relationship represented by equation (1). Therefore, by reading equation (1) from the memory 162 and using it, the frequency fr of the fluctuation current can be immediately calculated using the linearity between the fluctuation current Ir and the frequency fr of the fluctuation current, and the passband of the variable filter 130 can be adjusted. Thus, the fluctuation detection device 100 that can realize high-speed processing and detect fluctuation pulses with high accuracy can be provided.

[0088] In addition, the fluctuation detection device 100 further includes a memory 162 storing data representing the linear relationship represented by equation (2) and data representing equation (3). Therefore, by reading equations (2) and (3) from the memory 162 and using them, the frequency fr of the fluctuating current can be immediately calculated by taking into account the ambient temperature t and utilizing the linearity between the fluctuating current Ir and the frequency fr of the fluctuating current, and the passband of the variable filter 130 can be adjusted. Thus, the fluctuation detection device 100 can be provided which can realize high-speed processing and can detect the fluctuation pulse with high accuracy.

[0089] Furthermore, the fluctuation detection device 100 further includes a fluctuation pulse generation unit 150 that generates a fluctuation pulse based on the output signal of the variable filter 130 . Therefore, the variable filter 130 can be optimized according to the characteristics of the motor 23 .

[0090] Furthermore, the fluctuation detection device 100 further includes a filter 122 provided on the input side of the variable filter 130 and a filter 140 provided on the output side of the variable filter 130; the fluctuation current detected by the current detection unit 112 and the resistor 24 and passing through the filter 122, the variable filter 130, and the filter 140 in this order is input to the fluctuation pulse generation unit 150. Therefore, even if the characteristics of the fluctuation current of the motor 23 are disturbed, the fluctuation current can be detected with high accuracy by correctly removing the noise.

[0091] The seat device 10 includes: a seat 20 mounted on the vehicle 1 and capable of adjusting a position or an angle by a motor 23; a drive control unit 50 for controlling the drive of the motor 23; and a fluctuation detection device 100 for detecting a fluctuation current of the motor 23 and outputting the fluctuation current to the drive control unit 50. The fluctuation detection device 100 includes: a current detection unit 112 and a resistor 24 for detecting a fluctuation current generated when the motor 23 is driven; a voltage detection unit 111 for detecting a voltage Vm between terminals of the motor 23; a variable filter 130 for passing a component of a predetermined frequency band in the fluctuation current detected by the current detection unit 112 and the resistor 24; and a frequency adjustment unit 161 for adjusting the predetermined frequency band of the variable filter 130 so as to include the derived frequency of the fluctuation current, using a linear relationship expression for deriving the frequency of the fluctuation current based on the fluctuation current detected by the current detection unit 112 and the resistor 24 and the voltage Vm between terminals detected by the voltage detection unit 111.

[0092] Therefore, the frequency of the fluctuating current can be derived from the linear relationship between the fluctuating current and the inter-terminal voltage Vm, and the specified frequency band of the variable filter 130 can be adjusted according to the frequency of the fluctuating current, thereby suppressing the loss of the fluctuating pulse (missed detection of the fluctuation) and the erroneous detection of the fluctuating pulse. As a result, the rotation position of the motor 23 can be detected with high accuracy regardless of the magnitude of the load on the motor 23, and the seat 20 can be adjusted correctly.

[0093] Therefore, it is possible to provide a seat device 10 which, by using a linear relationship of the frequency fr of the fluctuating current derived from the fluctuating current Ir and the voltage Vm between the motor terminals, optimally controls the passband of the variable filter 130 according to the driving state of the motor 23, can detect the fluctuating pulse with high precision, and can correctly adjust the seat 20.

[0094] As mentioned above, although the wave detection device and the seat device which are exemplary embodiments of the present disclosure have been described, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and changes can be made without departing from the scope of the claims.

[0095] In addition, the present international application claims priority based on Japanese Patent Application No. 2022-106006, filed on June 30, 2022, the entire contents of which are incorporated herein by reference.

[0096] Description of Reference Numerals

[0097] 1 Vehicle

[0098] 10 Seat device

[0099] 20 seats

[0100] 23, 23A, 23B motors

[0101] 24 resistors (an example of a fluctuating current detection unit)

[0102] 50 Drive control unit

[0103] 100 Fluctuation Detection Device

[0104] 111 Voltage detection unit (an example of a motor voltage detection unit)

[0105] 112 Current detection unit (an example of a fluctuating current detection unit)

[0106] 121 filter

[0107] 122 filter (an example of the first filter)

[0108] 130 variable filters

[0109] 140 filter (an example of the second filter)

[0110] 150 wave pulse generating unit

[0111] 160MCU

[0112] 161 Frequency Adjustment Unit

[0113] 162 Memory

[0114] 170 Temperature Sensor

Claims

1. A fluctuation detection device, wherein: have: A fluctuating current detection unit that detects a fluctuating current generated when the motor is driven; A motor voltage detection unit detects the voltage between the terminals of the motor; a variable filter that allows a component of a predetermined frequency band in the fluctuating current detected by the fluctuating current detection unit to pass; as well as A frequency adjustment unit adjusts the above-mentioned specified frequency band of the above-mentioned variable filter so that the above-mentioned specified frequency band includes the frequency of the above-mentioned fluctuating current derived using a linear relationship, and the above-mentioned linear relationship is a linear relationship that derives the frequency of the above-mentioned fluctuating current based on the fluctuating current detected by the above-mentioned fluctuating current detection unit and the terminal voltage detected by the above-mentioned motor voltage detection unit.

2. The fluctuation detection device according to claim 1, wherein: The above linear relationship is expressed by the following equation (1): fr=α×Ir+β×Vm (1) Among them, Ir is the above-mentioned fluctuating current, fr is the frequency of the above-mentioned fluctuating current, α is the ratio of the change in the frequency of the above-mentioned fluctuating current to the change in the above-mentioned fluctuating current, and β is the ratio of the change in the frequency of the above-mentioned fluctuating current to the change in the above-mentioned terminal voltage.

3. The fluctuation detection device according to claim 1, wherein: A temperature sensor is also provided to detect the ambient temperature of the motor. The frequency adjustment unit adjusts the predetermined frequency band of the variable filter so that the predetermined frequency band includes the frequency of the fluctuating current derived using a linear relationship between the fluctuating current detected by the fluctuating current detection unit, the inter-terminal voltage detected by the motor voltage detection unit, and the ambient temperature detected by the temperature sensor. The above linear relationship is expressed by the following equation (2): fr=α×Ir×K+β×Vm (2) Wherein, Ir is the above-mentioned fluctuating current, fr is the frequency of the above-mentioned fluctuating current, α is the ratio of the change in the frequency of the above-mentioned fluctuating current to the change in the above-mentioned fluctuating current, K is the variable temperature coefficient expressed by the following equation (3), and β is the ratio of the change in the frequency of the above-mentioned fluctuating current to the change in the voltage between the above-mentioned terminals; K=1-γ×T (3) In the formula (3), γ is a predetermined temperature coefficient, and T is a temperature obtained by subtracting a predetermined reference temperature from the ambient temperature of the motor detected by the temperature sensor.

4. The fluctuation detection device according to claim 2, wherein: The device further includes a memory for storing data representing the linear relationship represented by the above equation (1).

5. The fluctuation detection device according to claim 3, wherein: The device further includes a memory for storing data representing the linear relationship represented by the above-mentioned equation (2) and data representing the above-mentioned equation (3).

6. The fluctuation detection device according to any one of claims 2 to 5, wherein: The invention further includes a fluctuation pulse generating unit for generating a fluctuation pulse based on an output signal of the variable filter.

7. The fluctuation detection device according to claim 6, wherein: Also available: a first filter provided on the input side of the variable filter; and The second filter is provided at the output side of the variable filter. The ripple current detected by the ripple current detection unit and passed through the first filter, the variable filter, and the second filter in this order is input to the ripple pulse generation unit.

8. A seat device, comprising: The seat is mounted on the vehicle and can be adjusted in position or angle by a motor; A drive control unit for controlling the drive of the motor; as well as a fluctuation detection device for detecting the fluctuation current of the motor and outputting the fluctuation current to the drive control unit; in, The above-mentioned fluctuation detection device comprises: A fluctuating current detection unit that detects a fluctuating current generated when the motor is driven; A motor voltage detection unit detects the voltage between the terminals of the motor; a variable filter that allows a component of a predetermined frequency band in the fluctuating current detected by the fluctuating current detection unit to pass; as well as A frequency adjustment unit adjusts the above-mentioned specified frequency band of the above-mentioned variable filter so that the above-mentioned specified frequency band includes the frequency of the above-mentioned fluctuating current derived using a linear relationship, and the above-mentioned linear relationship is a linear relationship that derives the frequency of the above-mentioned fluctuating current based on the fluctuating current detected by the above-mentioned fluctuating current detection unit and the terminal voltage detected by the above-mentioned motor voltage detection unit.

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