JP3780212B2 - Active vibration control method of actuator mounted engine mount using adaptive control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an active vibration control method using an adaptive control method for actively removing vibration of a controlled object.
[0002]
[Prior art]
Conventionally, as an active vibration control method using an adaptive control method, for example, adaptive control using an adaptive least mean square filter (hereinafter referred to as Filtered-X LMS) as shown in FIG. 5 is known. That is, for example, a crankshaft rotation pulse or an ignition pulse signal is taken out from a vibration generation source 35 such as an automobile engine to be controlled by a sensor, and is shaped into a pulse signal s having the same frequency as the control target signal. Further, the vibration from the vibration generating source 35 is propagated as an external force d through the transmission system 36 (G ′) into the vehicle interior. The pulse signal s is converted into a sine wave having the same frequency as that of the control target signal by the reference signal generation unit 1 to be a reference signal x. The reference signal x is subjected to amplitude compensation and phase compensation by the filter coefficient of the adaptive filter W2 that is a function of the amplitude compensation coefficient and the phase compensation coefficient, and an output signal y is formed.
[0003]
The output signal y is input to the transfer path (transfer function G) 3 of the control target system, and the processing signal z is output via the transfer path 3 of the control target system. The estimated transfer function G ^ 4 marked with ^ is an estimated transfer function obtained by measuring the transfer path (transfer function G) 3 of the control target system in advance by impulse response measurement, a frequency sweep excitation test, or the like. Yes, the estimated value of the transfer path (transfer function G) 3 of the control target system is stored in correspondence with each frequency of the control target in the control program, and quoted when the adaptive filter is updated.
[0004]
The processing signal z is added with an external force d that has passed through the transmission system 36 (G ′), such as engine vibration, and is detected by the sensor as an observed value. In the vibration control, the detection value target of the sensor is 0, and the difference from the target is the error signal e. Using the error signal e and the estimated value g of the estimated transfer function 4, the filter coefficient of the adaptive filter W is sequentially updated by the FIR filter (finite impulse response digital filter) 5. As described above, in the adaptive control system using the Filtered-X LMS, the external force is removed by the processing signal z that has been subjected to amplitude and phase compensation using the adaptively updated adaptive filter W.
[0005]
On the other hand, a delay harmonic synthesizer least mean square filter (hereinafter referred to as DXHS LMS) as shown in FIG. 6 is used as another adaptive control method for reducing the calculation amount of filter coefficients in the adaptive control method using Filtered-X LMS. The adaptive control method used is known. In this adaptive control method, for example, a crankshaft rotation pulse or the like is extracted from a vibration source 35 such as an automobile engine which is a signal source by a sensor, and the frequency determination unit 41 determines that the frequency is a control target frequency ω. At the same time, a control target signal having a control target frequency ω is selected and output to the adaptive filter W42 as a sine wave input signal x. The input signal x is subjected to amplitude compensation and phase compensation by the filter coefficient of the adaptive filter W42, and is combined with a sine wave output signal y and output. The output signal y passes through the transfer path (transfer function G) 43 of the control target system, and then the processed signal z is output. The processing signal z is added with an external force d that has passed through the transmission system 36 (G ′), which is vibration of the engine, and is detected by the sensor as an observed value. In the vibration control, the detection value target of the sensor is 0, and the difference from the target is the error signal e. Using the error signal e and the estimated value g of the estimated transfer function 44, the filter coefficient of the adaptive filter W42 is sequentially updated by the digital filter 45 (DXHS LMS).
[0006]
As described above, the adaptive control algorithm using the DXHS LMS does not require a convolution operation for coefficient update, and does not require a convolution operation in generating a reference signal. In vibration or noise, when the fundamental wave and its higher order components are controlled, no external harmonic signal is required for input. Further, it is possible to perform arithmetic processing only from the basic period without calculating virtual input internally, and the convolution calculation for updating the filter coefficient and generating the reference signal becomes unnecessary.
[0007]
[Problems to be solved by the invention]
By the way, in the active vibration control method using each adaptive control method used for vibration control of a vehicle or the like, a low-cost microcomputer is used to reduce the control cost. In this case, since it is difficult to employ a floating-point calculation with a large calculation load, particularly in the control calculation part, a fixed-point calculation with a small calculation load is employed. However, in fixed-point arithmetic, the range of numerical values that can be handled is small, so that the arithmetic accuracy is inferior to that of floating-point arithmetic. Furthermore, in a vehicle or the like to be controlled, sufficient signal sensitivity may not be obtained depending on the frequency. In such a case, calculation accuracy is further deteriorated. As described above, since the filter coefficient calculation result with high accuracy cannot be obtained by the fixed point calculation, there is a possibility that the output signal may diverge. On the other hand, it is possible to cope with a change in signal level on the sensor side that detects the error signal. However, in this case, a dedicated sensor is required every time the control object changes, and it is very complicated and costly to cope with this.
[0008]
The present invention is intended to solve the above-described problem. When the level of an error signal due to a difference in the control state in a control target is low, even if fixed-point arithmetic is used, an appropriate output signal does not diverge. It is an object of the present invention to provide an active vibration control method for an engine mount with an actuator using an adaptive control method capable of performing calculations at low cost.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the structural feature of the invention according to claim 1 is the same frequency as the frequency of the input pulse signal in the signal generation unit based on the periodic input pulse signal from the vibration generating source. An input signal of the control frequency is formed, and amplitude and phase compensation is performed on the input signal by a filter coefficient that is a function of the amplitude coefficient and phase coefficient of the adaptive filter, and the output signal subjected to the amplitude and phase compensation is transmitted to the controlled system. After passing through the path, the output after passing through the transfer path and the external force from the vibration source are added, and the input signal is subjected to amplitude and phase processing by the error signal that is the result of addition and the estimated transfer function that is defined in advance for the control target system Adaptive control method in which the amplitude coefficient and phase coefficient are sequentially updated by a digital filter based on the processed signal and the external force is suppressed by the output after passing through the transmission path In the active vibration control method of the actuator mounting engine mount used, calculation by the adaptive control method are those carried out by fixed-point arithmetic, and in accordance with the control state of the control object system, amplified by the amplifying means an error signal Thus, the amplifying means includes an amplifier having a plurality of different amplification degrees according to a difference in the control state in the control target system, and a switching means for switching the connection of the error signal input line to any one of the amplifiers, The connection is switched to the corresponding amplifier by the switching means according to the difference in the control state in the control target system .
[0010]
In the invention according to claim 1 configured as described above, an input signal having a control frequency that is the same as the frequency of the input pulse signal is formed in the signal generation unit based on the periodic input pulse signal from the vibration generation source. Then, the amplitude and phase compensation is performed on the input signal by the filter coefficient which is a function of the amplitude coefficient and the phase coefficient of the adaptive filter. After the amplitude and phase compensated output signal passes through the transmission path of the control target system, an error signal is obtained by adding the output after passing through the transmission path and the external force from the vibration generating source. Based on this error signal and a processed signal obtained by subjecting the input signal to amplitude and phase processing by a preliminarily estimated transfer function of the control target system, the digital filter sequentially updates the amplitude coefficient and the phase coefficient by fixed point arithmetic.
[0011]
Here, for example, when performing a fail check of the control target system, since the error signal is at a normal amplitude level, the error signal is directly input to the digital filter. On the other hand, when the level of the error signal is low, for example, when measuring the transfer function or during normal control, amplification is performed to increase the signal level according to the level of the error signal. Therefore, the level of the error signal input to the digital filter is always set to an appropriate value. As a result, even when a fixed-point operation whose calculation accuracy is not always sufficient is adopted, an appropriate operation that does not cause divergence of the output signal can be performed as in the case of performing the floating-point operation.
[0012]
Further, the structural feature of the invention according to claim 2 is that, in the active vibration control method for an actuator-mounted engine mount using the adaptive control method according to claim 1, in the case of a fail check as a control state, This is a normal gain, and is an amplification gain during actual vibration control .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 schematically shows an active vibration removal system using an adaptive control method using DXHS LMS applied to the vehicle according to the embodiment, and FIG. 2 schematically shows an engine mount by a sectional view. FIG. 3 is a block diagram showing an active control configuration of the vibration removal system. The vibration removal system includes an actuator-mounted engine mount 20 mounted on the vehicle body 10, a rotation speed sensor 12 that detects the rotation speed of the engine 11 that is a vibration generation source, and a pickup acceleration sensor 14 that is provided below the seat 13. The electric control device 30 is provided.
[0014]
For example, as shown in FIG. 2, the engine mount 20 includes a vibration isolation rubber 22 in a cylindrical case 21 and an electromagnetic actuator 23 that controls the dynamic displacement of the engine below the vibration isolation rubber 22. . The anti-vibration rubber 22 is fixed to the inner wall of the case 21 and attached to the fixing bracket 24. The fixing bracket 24 is provided with a stopper portion 22 a of the vibration proof rubber 22 toward one end of the case 21. A fixed shaft 25 is attached to the axial center position of the fixing bracket 24 in the axial direction, and a tip thereof protrudes from a through hole 21 a provided on one end side of the case 21. A fixed shaft 26 is provided at the other end of the case 21. The engine mount 20 is fixed to the vehicle body 10 by a fixed shaft 26, and supports the engine 11 by attaching the engine 11 to the fixed shaft 25.
[0015]
A rotation speed sensor 12 is attached to the crankshaft of the engine 11, and a pickup acceleration sensor 14 is attached to the lower part of the seat 13. The rotation speed sensor 12 outputs a crankshaft rotation pulse signal, and based on this, the control unit 31 determines the fundamental frequency of the output signal. Further, the pickup acceleration sensor 14 outputs an error signal, and measures and outputs the phase characteristics of the system in advance.
[0016]
The electric control device 30 of the vibration removal system includes a control unit 31 formed of a microcomputer, and an amplification unit 32 and an adaptive control unit 40 using DXHS LMS are provided in a part thereof. The rotational speed sensor 12 and the pickup acceleration sensor 14 are connected to the input side of the control unit 31. The pickup acceleration sensor 14 is connected to the adaptive control unit 40 via the amplification unit 32. The amplifying unit 32 includes two amplifiers 33a and 33b, a simple signal line 33c, and a changeover switch 33d. The change-over switch 33d switches the connection between the input line of the pickup acceleration sensor 14 and any one of the amplifiers 33a and 33b and the simple signal line 33c in accordance with a command from the control unit 31. The amplifier 33a has an amplification degree A (A> 1), and the amplifier 33b has an amplification degree B (B> A). The output side of the control unit 31 is connected to the actuator 23 of the engine mount 20 via a pulse width modulation driver (PWM driver) 34.
[0017]
As shown in FIG. 3A, the adaptive control unit 40 is basically composed of an adaptive control system using the DXHS LMS shown in FIG. 6, and in addition to this, an error signal is input to the digital filter 45. Amplifiers 33a and 33b and a signal line 33c of the amplifying unit 32 and a changeover switch 33d are disposed on the signal line to be transmitted. As shown in FIG. 3B, the amplifying unit 32 may be provided with AC coupling capacitors 33f and 33e in front of the amplifiers 33a and 33b, respectively. As a result, it is possible to take measures against environmental factors such as temperature and drift due to each amplifier itself.
[0018]
Next, the operation of the embodiment will be described.
For example, in the control state, when performing a fail check with a zero point fixed and pasted at 5 V as an error signal, normal gain (amplification factor 1) is used, and during actual vibration control, amplification gain (amplification factor A> 1) is used. It is assumed that it is prescribed in advance that an amplification gain (amplification degree B> A) is adopted when measuring the transfer function of the control system.
[0019]
When the control is a transfer function measurement, the control unit 31 calculates a control frequency in the frequency determination unit 41 based on the input pulse signal s from the rotation speed sensor 12, and also receives an input signal x that is a sine wave signal of the control frequency. Output. Next, the control unit 31 processes the input error signal e. Here, since the amplification gain B is employed, the control unit 31 switches the connection of the error signal input line to the amplifier 33b by the changeover switch 33d. The digital filter 45 uses the error signal e amplified by the amplifier 33b and the processed signal g obtained by processing the input signal x using the pre-estimated transfer function 44 of the control target system. The phase coefficient φ is updated, and the updated amplitude coefficient a and phase coefficient φ are output. Further, in the adaptive filter W42, the control unit 31 performs amplitude compensation and phase compensation of the input signal x using the updated filter coefficient, and outputs an output signal y.
[0020]
In actual vibration control, the control unit 31 switches the connection of the input line to the amplifier 33a by the changeover switch 33d when processing the input error signal e. As a result, the error signal is amplified to an amplification degree A and input to the digital filter 45. Due to the error signal having an increased level in this way, the updating process of the amplitude coefficient a and the phase coefficient φ is appropriately performed in the digital filter 45 so that no divergence occurs. Further, since the amplification gain is 1 at the time of the fail check, the control unit 31 switches the connection of the input line to the signal line 33c by the changeover switch 33d and processes the normal adaptive control when processing the input error signal e. I do.
[0021]
As described above, in this embodiment, when the error signal is at a normal amplitude level, for example, when performing a control system fail check, the error signal is input to the digital filter as it is. Further, when the vibration level of the error signal is low, for example, when measuring the transfer function or during normal control, amplification is performed to increase the signal level according to the level of the error signal. Thus, in this embodiment, when the signal level of the error signal e input to the digital filter 45 is low according to the control state in the control target system, it is appropriately amplified according to the level. The level of the error signal e input to the digital filter 45 is always set to an appropriate value.
[0022]
As a result, the control unit 31 employs fixed-point arithmetic whose calculation accuracy is not always sufficient, but also by this, as with floating-point arithmetic, it is possible to perform appropriate arithmetic that does not cause divergence of the output signal at low cost. Can do. Furthermore, since the level of the error signal can be changed by the control unit 31, it is not necessary to prepare sensors having different specifications even when the counterpart vehicle to which the present invention is applied changes.
[0023]
In the above embodiment, the control mode is a normal gain (amplification degree 1) in the case of fail check, and an amplification gain (amplification degree A) in actual vibration control, and the transfer function of the control system is measured. In some cases, the amplification gain (amplification degree B> A) is used, but the present invention is not limited to this, and the gain is appropriately changed according to the control state in the control target system. For example, in the case of fail check and actual vibration control, the normal gain may be used, and the amplification gain may be used only when measuring the transfer function of the control system. In some cases, only the actual vibration control is used as the amplification gain, and the normal gain is used when measuring the transfer function of the control system and during the fail check. Furthermore, in any of the fail check, the actual vibration control, and the transfer function measurement of the control system, an amplification gain may be used. Other combinations are possible.
[0024]
Next, specific examples of the above embodiment will be described.
As shown in FIG. 4, in the vibration control, the calculation is a fixed point calculation, and the vibration level (indicated by a dotted line in the figure) when the amplification unit is set to the normal gain as in the conventional case is the floating point calculation. It is clear that the vibration level is significantly inferior to the vibration level (indicated by the thin solid line in the figure). On the other hand, in vibration control, the vibration level (indicated by a thick solid line in the figure) when the amplifying unit 33 is switched to the amplifier 33a according to the signal level is almost the same as the vibration level when the calculation is a floating point. The vibration level is improved significantly compared to the normal gain.
[0025]
In each of the above embodiments, the vibration removal system using adaptive control by DXHS LMS is described. However, the present invention is similarly applied to other adaptive control systems using Filtered-X LMS or the like. Can do. Further, in the above embodiment, the vibration removal system according to the present invention is used for removing periodic vibrations and noises in other vibration generation systems. Can also be used.
[0026]
【The invention's effect】
According to the present invention , since the level of the error signal input to the digital filter is always maintained at an appropriate value, the calculation of the error signal can be performed by using a fixed-point operation whose calculation accuracy is not always sufficient. As in the case of an expensive floating point calculation with high calculation accuracy, it is possible to perform appropriate calculation at low cost without causing divergence in the amplitude or phase of the output signal. Furthermore, since the error signal can be changed by control, it is not necessary to prepare sensors having different specifications even when the counterpart vehicle to which the present invention is applied changes. Moreover, since it is switched to the amplifier corresponding by switching means according to a difference in the control state of the control object system can be an error signal to an appropriate level by constantly amplifying means.
[Brief description of the drawings]
FIG. 1 is a schematic diagram schematically showing an active vibration removal system using an adaptive control method using DXHS LMS according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional view showing an example of an engine mount used in a vehicle to which the vibration elimination system is applied.
FIG. 3 is a block diagram showing an adaptive control system (DXHS LMS) of the vibration removal system.
FIG. 4 is a specific example of a relationship between a vibration level and an engine speed (frequency) when an error signal in a fixed point arithmetic is a normal gain and an amplification gain, and a floating point arithmetic that is a comparative example; It is a graph which shows the relationship between a vibration level and an engine speed (frequency).
FIG. 5 is a block diagram showing an adaptive control system (Filtered-X LMS) as a conventional example.
FIG. 6 is a block diagram showing a conventional adaptive control system (DXHS LMS).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Car body, 11 ... Engine, 12 ... Speed sensor, 14 ... Pick-up acceleration sensor, 20 ... Engine mount, 23 ... Actuator, 30 ... Electric control device, 31 ... Control part, 32 ... Amplifying part, 33a, 33b ... Amplifier , 33c ... signal line, 33d ... changeover switch, 33e, 33f ... AC coupling capacitor, 35 ... vibration source, 36 ... transmission system, 40 ... adaptive control unit, 42 ... adaptive filter W, 43 ... control target system transmission Path (transfer function G), 44 ... Estimated transfer function G ^, 45 ... Digital filter (DXHS LMS).

Claims (2)

Based on the periodic input pulse signal from the vibration source, the signal generation unit forms an input signal having a control frequency that is the same as the frequency of the input pulse signal, and the amplitude coefficient of the adaptive filter for the input signal and Amplitude and phase compensation is performed using a filter coefficient that is a function of the phase coefficient, and after the output signal subjected to amplitude and phase compensation has passed through the transmission path of the control target system, the output after passing through the transmission path and the vibration source An external force is added, and the amplitude coefficient and phase are obtained by a digital filter based on an error signal that is a result of the addition and a processing signal obtained by performing amplitude and phase processing on the input signal using a pre-estimated transfer function of the control target system. It performed sequentially updated coefficients actuator mounted engine using adaptive control method so as to suppress the external force by the output after the transmission path passing In the active vibration control methods und,
Calculation by the adaptive control method are those carried out by fixed-point arithmetic, and in accordance with the control state of the control object system, so as to amplify the amplifying means said error signal,
The amplifying unit includes a plurality of amplifiers having different amplification degrees according to a difference in a control state in the control target system, and a switching unit that switches connection of any one of the error signal input lines to the amplifier. An active vibration control method for an actuator-mounted engine mount using an adaptive control method, wherein connection is switched to a corresponding amplifier by the switching means according to a difference in control state in a target system . The active state of the engine mount with an actuator using the adaptive control method according to claim 1, wherein the control state is a normal gain in the case of a fail check and an amplification gain in an actual vibration control. Vibration control method.

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