JPH0694891B2 - Vehicle body vibration reduction device - Google Patents

Description

The present invention relates to a vehicle body vibration reduction device that reduces vehicle body vibration of a vehicle.

Generally, in a low engine speed region such as when the vehicle is idling, the vehicle body vibration due to the engine rotation exists near the resonance point of the vehicle body, and thus a large vehicle body vibration occurs. This large vibration of the vehicle body causes an unpleasant sensation to the occupant due to an increase in the muffled noise in the room without being accompanied by the mutual cancellation of the vibrations and wind noises, which occur during high-speed driving.

In recent years, a vehicle body vibration reduction device has been developed which reduces vibration near the resonance point of a vehicle body by driving a vibration exciter.

Here, this type of vehicle body vibration reducing device will be described. FIG. 1 shows an example of a front portion of a vehicle. The body frame 1 of the vehicle supports front and rear end portions of a horizontally mounted engine E, and a vibrator 2 is attached to the center of the front end of the body frame 1. It is a structure. Then, when the vibration exciter 2 is driven, a desired vibration is transmitted to the vehicle body B via the body frame 1. In this case, the vibration by the vibration exciter 2 is applied so as to suppress the vibration of the vehicle body, that is, the node of the vibration exists in the vehicle compartment as described later.

FIG. 2 is a circuit block for driving the vibration exciter 2. The signal input end for inputting a signal to the microcomputer M includes a vehicle speed sensor 3, an engine speed sensor 4, an acceleration sensor 5, and an engine speed. Corresponding to the ignition pulse generator 6 in other words the engine E. Here, the vehicle speed sensor 3 outputs a vehicle speed signal and is used to enable driving of the vibrator 2 at a vehicle speed equal to or lower than a set vehicle speed. This is because the resonance vibration region of the vehicle body is detected by the vehicle speed. In addition, the engine speed sensor 4
Is for detecting the engine speed, about 600 rpm ~ 900r
It is used to enable driving of the vibration exciter 2 at a rotation speed within the range of about pm. This range is determined because the resonance vibration region of the vehicle body occurs at this rotation speed. The output signals of the vehicle speed sensor 3 and the engine speed sensor 4 are also used to determine the phase and gain of the vibration signal of the vibrator according to the detected vehicle speed and engine speed. Therefore, when the vehicle speed and the number of revolutions under a constant condition are detected, the phase and the gain corresponding to the values are tentatively determined. In this way, the vehicle speed sensor 3 and the engine speed sensor 4 are provided to determine whether or not to drive the vibration exciter 2, and to determine the phase and the gain of the vibration signal when the vibration sensor 2 is driven.

The acceleration sensor 5 is for detecting the vibration of the vehicle body, and is strictly for obtaining the acceleration due to the vibration. This acceleration G represents the state of vibration of the vehicle body, and a signal having the presence or absence of vibration and an amplitude is obtained. The acceleration sensor 5 can be arranged at a position where vibration of the vehicle should be reduced, for example, at the driver's seat, the rear seat, or all seats, or at the center of the rear seat or the center of the passenger compartment. It is also possible to provide a combination of the output states of the acceleration sensor 5 which is not at the position to be reduced but which is arbitrarily arranged so as to reduce the vibration at a predetermined position. That is,
The acceleration sensor 5 is arranged in relation to the position where vibration should be reduced.

The ignition pulse generator 6 is a pulse generator that outputs the engine speed, and outputs the pulse shown in FIG. 2a. The output pulse of the ignition pulse generator 6 is generated in synchronism with the rotational speed of the vehicle because the resonance vibration of the vehicle body is caused by the vibration of the engine, that is, the rotational speed of the engine. Will be synchronized with. A waveform shaping section 7 connected to the ignition pulse generator 6 removes noise from the ignition pulse waveform and shapes it into a rectangular wave shown in FIG. 2b. Further, in the SIN wave generating section 9 connected to the waveform shaping section 7, the SIN wave of the same phase is formed based on the rectangular wave of FIG. 2B to generate the excitation signal shown in FIG. 2C.

The inside of the microcomputer M includes a phase controller 10 connected to the SIN wave generator 9, a gain controller 12 connected to the phase controller 10 and outputting an output to an amplifier 11, a phase controller 10 and a gain controller 12. It has a controller 13 that outputs a command and receives outputs from a vehicle speed sensor 3, an engine speed sensor 4, and an acceleration sensor 5. Then, in this microcomputer, the SIN wave synchronized with the engine speed, that is, the vehicle body vibration is input to the phase control unit 10, the vehicle speed signal from the vehicle speed sensor 3 is equal to or less than the set vehicle speed, and the constant speed range from the engine speed sensor 4 is set. The rotation speed signal in the controller 13 is input to the controller 13, and the
The waves are phase-shifted and controlled to the waveform shown in Figure 2d. Further, the phase-shifted SIN wave is applied to the gain control unit 12
In Fig. 2, the gain is controlled by the vehicle speed and the rotational speed, and the waveform shown in Fig. 2e is obtained. As a result, the output of the microcomputer M, which is output from the gain control unit 12 to the amplifier 11, is different in phase and amplitude with respect to the SIN wave of the SIN wave generating unit 9 synchronized with the engine speed that is the ignition pulse, that is, the vehicle body vibration. Will have. The amplifier output that amplifies this microcomputer output drives the vibration exciter 2. However, since the vibration signal differs from the vehicle body vibration in phase and gain, the vibration of the vibration exciter 2 exerts some influence on the vehicle body vibration. Vibration can be suppressed.

Vehicle speed signal from vehicle speed sensor 3, engine speed sensor 4
The original SIN wave is phase-shifted by the rotation speed signal from the gain-controlled vibration signal, and if the vibration signal is driven by this vibration signal, the vibration of the vehicle body is suppressed. Should be. Here, the output of the acceleration sensor 5 is used in order to more strictly control the vibration. That is, the vehicle body vibration is detected by the acceleration sensor 5 after the vibration generator 2 is driven by the vibration signal. Here, if the vehicle body vibration can be damped as desired and the output of the acceleration sensor 5 is not output by driving with the above-mentioned vibration signal which is the phase-shifted and gain-controlled SIN wave, there is no problem at all.
If harmful vehicle vibration is still present and acceleration is detected, this time, due to the presence of the detection signal from the acceleration sensor 5,
Again, the controller 13 commands the phase control unit 10 and the gain control unit 12 to perform phase shift and gain control of a constant width for the excitation signal. In this way, the vibration detection by the acceleration sensor 5, the constant phase shift of the excitation signal, and the gain control are repeated to finally bring the acceleration sensor 5 into a state of being damped.

Here, the cancellation or damping of the vibration signal, that is, the vibration of the vibration exciter and the vibration of the vehicle body will be described. Vibration caused by engine rotation, in this case low-frequency vibration that causes resonance of the vehicle body, if the vibration exciter has a large enough capacity to suppress this resonance vehicle body vibration, vibration with the same amplitude as the opposite phase of the vehicle body vibration The vibration of the vehicle body is canceled by adding the. That is, the vehicle body is completely damped by generating the same amplitude and phase that is shifted by 180 ° with respect to the vehicle body vibration by the vibration exciter.

Therefore, in the microcomputer M, SIN depending on the engine speed
If the function to reverse the wave and adjust the gain of this SIN wave so that the vibration of the vibration exciter and the vibration of the vehicle body have the same amplitude, the vibration can be completely damped. Further, even if the same amplitude is not applied, vibration can be suppressed to a certain extent even if it is applied in a reverse phase with a smaller amplitude. In addition, in this case, the position of the engine E and the position of the exciter are different from each other, so that the excitation signal cannot be completely reversed in phase with respect to the SIN wave due to the vibration of the vehicle body, and the vibration of the exciter causes vibration of the vehicle body. The excitation signal is adjusted so as to be in the opposite phase.

Such anti-phase excitation is of course possible, but in view of the reality that the capacity of the exciter is generally smaller than the resonance vibration, moreover, even if only a part of the passenger compartment is completely attenuated without evenly damping or damping the entire vehicle body, In order to meet the requirement to suppress the vibration at or near the end, the vibration of the vibration exciter, that is, the vibration signal, is phase-shifted so that the waveform of the vehicle body vibration that hits a part of the vehicle interior to be damped becomes zero vibration. A function to adjust the gain is required. In the microcomputer M shown in FIG. 2, not only the anti-phase damping described above but also a part of damping can be controlled.

Returning to FIG. 2, when a signal below the set vehicle speed from the vehicle speed sensor 3 is not output or when a signal within the set range from the engine speed sensor 4 is not output, the stop signal of the amplifier 11 is output from the microcomputer M. Therefore, the excitation signal is not input to the exciter 2 and the exciter 2 is not driven. At the same time, the vibrating machine 2 is locked by the hold mechanism 14 and the vibrating machine is mechanically fixed.

FIG. 3 is a flow chart for generating an excitation signal for which phase control and gain control have been carried out. The microcomputer M of FIG.
Shows the function of. The flow chart shown in FIG. 3 is roughly divided into a route for driving or non-driving the vibrator by detecting the vehicle speed and the engine speed, a phase and a gain corresponding to the vehicle speed and the engine speed when driving the vibrator. Setting, output detection of the acceleration sensor by addition / subtraction of unit phase, and output detection of acceleration sensor by addition / subtraction of unit gain. The details will be described below with reference to FIG. Second
The vehicle speed V detected by the vehicle speed sensor 3 shown in the figure is input to the controller 13 and step B1 is executed to determine whether the vehicle speed is higher than a predetermined speed V ₀ . The vehicle speed V ₀ is set to the maximum vehicle speed when it is harmful due to the resonance of the vehicle body, and the minimum vehicle speed limit of the normal vehicle speed measurement. Vehicle speed V is set vehicle speed V ₀
If it is larger, the amplifier 11 is turned off at step B32, and then the hold mechanism 14 is turned on at step B33.
It is determined whether the vibration exciter 2 is mechanically locked. If it is determined in step B33 that the vibration exciter is locked, in step B35 the locked state is continuously maintained, and if it is determined that it is not locked, the hold mechanism 14 is pressed in step B34.
A lock instruction signal is transmitted to the controller 13 from the controller 13, and the vibration exciter 2 is locked.

When the vehicle speed V is lower than the set vehicle speed V ₀ , this time, the second
The engine speed N detected by the engine speed sensor 4 shown in the figure is input to the controller 13 and step B2
Is executed, and the engine speed N is equal to the predetermined speed N1 and
It is determined whether it is within the range of N2. In this case, the rotation speed is N1 = 600r.pm N2 = 900r.pm, for example. When the engine speed N is not within the predetermined range, that is, N <N
When 1 or N> N2, the vehicle body resonance does not occur and the operation after the off-step B32 of the amplifier 11 described above is performed, and the vibration exciter 2 is mechanically locked.

When the engine speed N is within a predetermined range at step B2, that is, when N1 ≦ N ≦ N2, at step B3, the phase φ and the gain are set in the microcomputer M according to the engine speed N and the vehicle speed V. A corresponding map is selected from various maps in which F and F are stored in advance. This is a vibration mode that has been known from experience in the case of a constant vehicle speed or engine speed, so it is decided to obtain the basic vibration signal of the vibration exciter that suppresses this vibration. The selected map determines the phase φ and the gain F suitable for damping.

Based on the determined map, step B4 determines the phase φ ₁ and gain F1, and step B5 outputs the phase φ ₁ gain F1. That is, in the microcomputer M,
The SIN wave based on the engine speed shown in FIG. 2 is subjected to phase control or gain control to generate an excitation signal composed of the phase φ ₁ and the gain F1 for excitation. Then,
As shown in step B6, the unit phase Δφ is added in advance to generate the excitation signal φ ₂ = φ ₁ + Δφ. And this Δφ
Then, it is determined in step B7 whether or not the vibration, that is, the output of the acceleration sensor 5 has been reduced. If the output of the acceleration sensor decreases, the step
And _{φ 3 = φ 2 + Δφ =} φ 1 + 2Δφ more [Delta] [phi to phi ₂ as is applied at B8B9, it determines whether again the output of the acceleration sensor 5 at step B10 is reduced. In this way, the vibration signal is phase-shifted by a constant (unit) phase Δφ to detect when the output of the acceleration sensor 5 is most reduced. The phase Δφ is sequentially added to determine whether or not the decrease is greatest, and when the output of the acceleration sensor 5 changes from decrease to increase, that is, when the determination of step B10 detects NO (increase G), the acceleration sensor Output exceeds the minimum, so
And the calculation of φ _n = φ _{n + 1} -Δφ determines the phase phi _n striking the minimum output at step B11.

When the output of the acceleration sensor is increased in step B7 for determining whether the output of the acceleration sensor 5 is reduced by initially adding the phase of Δφ, it means that the phase is shifted in the direction of increasing the vibration. Therefore, at step B12 φ ₂
= Φ ₁ −Δφ is calculated. Here, it is determined in step B13 whether the output of the acceleration sensor 5 has decreased.
When reduced, step B14, B15 at φ ₃ = φ ₂ -Δ
φ = φ ₁ -2Δφ further reduced the Δφ as step B
At 16 it is again determined whether the output of the acceleration sensor 5 has decreased. In this way, the vibration signal is phase-shifted by a constant phase to detect the phase when the output of the acceleration sensor 5 is most reduced. To determine whether or not it has decreased the most, the phase Δφ is sequentially decreased, and when the output of the acceleration sensor 5 turns from decrease to increase, it means that the output of the acceleration sensor has exceeded the minimum, and therefore step B17 Then, φ _n = φ _{n + 1} + Δφ is calculated to determine the phase φ _n corresponding to the minimum output of the acceleration sensor.

If the output of the acceleration sensor 5 is increased in step B13 in which it is determined whether the output of the acceleration sensor 5 is reduced by reducing the phase of Δφ in step B12, φ ₁ is set to the correct phase, and The output will be the lowest, and the phase φ ₁ will be determined as it is. In this way, the optimum phase is determined.

Next, the same operation is performed for the gain. That is, the gain is repeatedly increased in steps B20, B21, B22, B23, B24 and the minimum output of the acceleration sensor is obtained, and the gain is repeated in steps B20, B25, B26, B27, B28, B29, B30. There is a route for decreasing to obtain the minimum output of the acceleration sensor, and a route for keeping the gain fixed at F1 as shown in step B31. This gain control is the same as the phase control, so its explanation is omitted.

In this way, the vibration signal with the phase φ _n and the gain F _n adjusted is obtained, and the vibration generator 2 is driven by this vibration signal to obtain the minimum output of the acceleration sensor to suppress the vibration. It

By the way, when the above-described control is performed when the door is closed in the vehicle body vibration reducing apparatus described above, a large vibration is generated. To explain the reason, the vibration caused by closing the door is detected by the acceleration sensor 5, and the microcomputer M immediately issues a command to the vibration exciter 2 to cancel the vibration caused by the door closing. Due to its mechanical inertia, the response is delayed for the command. Therefore, after the vibration due to the closing of the door has subsided, the vibration exciter 2 operates based on the command. Moreover, since this vibration is so large as to cancel the vibration due to the door closing, after the large vibration due to the door closing occurs in the vehicle body, it is further vibrated by the vibration exciter 2.

In view of the above situation, an object of the present invention is to provide a vehicle body vibration reduction device that does not increase the vehicle body vibration by the vibrator 2 after the door is closed.

The present invention that achieves such an object includes (1) a shaker that is attached to a vehicle body and that generates additional vibration to the vehicle body, and a position that detects acceleration due to the vehicle body vibration and that reduces the vehicle body vibration in the vehicle interior. Alternatively, an acceleration sensor arranged at an arbitrary position capable of detecting vehicle body vibration at the same position, and a detection signal of the acceleration sensor is input and stored as a sampling value at regular time intervals, and the frequency of vehicle body vibration caused by engine vibration is also stored. The basic excitation signal is generated by adjusting the phase and gain of the signal based on the engine speed, and the excitation signal is adjusted by adjusting the phase and gain of the basic excitation signal according to the stored sampling value. And a control means for supplying the detection signal to the machine, the control means storing the detection signal as a sampling value when the differential value of the detection signal of the acceleration sensor is less than a certain value. With, in the case where the differential value of the constant or is characterized by moving from delayed a certain time without storing the sampled values for the next sampling operation.

(2) A vibrator attached to the vehicle body for generating additional vibration to the vehicle body, and a vehicle body vibration at a position where acceleration due to the vehicle body vibration is detected and the vehicle body vibration is to be reduced or at the same position. An acceleration sensor arranged at an arbitrary detectable position and a detection signal of the acceleration sensor are input and stored as a sampling value at fixed time intervals, and a phase and a gain of a frequency signal of a vehicle body vibration caused by engine vibration are stored in the engine. A control means for generating a basic excitation signal by adjusting based on the number of revolutions, and supplying an excitation signal to the exciter, the excitation signal having the phase and gain of the basic excitation signal adjusted according to the stored sampling value; When the differential value of the detection signal of the acceleration sensor is less than a certain value, the control means delays the detection signal for a certain period of time and stores it as a sampling value. In both cases, when the differential value is equal to or more than the predetermined value, a value obtained by adding a value obtained by multiplying the difference between the stored previous sampling value and the value of the detection signal by a predetermined reduction coefficient to the previous sampling value is a sampling value. It is characterized by storing as.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention. In this embodiment, the circuit shown in FIG. 2 is provided with a differentiating circuit 8, which differentiates the detection signal G from the acceleration sensor 5 and inputs the differential signal to the controller 13. When the value of the differential signal is small, the controller 13 to which the differential signal is input samples and stores the detection signal G at regular intervals. Then, the stored sampling value is read out and averaged to obtain the value of the detection signal G, and the phase and the gain are adjusted based on this value. Therefore, when the differential signal is small, that is, when a large vibration such as closing of the door is not generated, the vibration exciter 2 is actuated by the vibration of which the phase and the gain are adjusted, and the vibration of the vehicle body is reduced.

On the other hand, when the door is closed and a large vibration occurs, the controller 13 of the microcomputer M operates as shown in FIG. 5 or FIG.

First, the operation will be described with reference to FIG. First, the detection signal G and its differential signal are input. This time Is smaller than the constant value A, the detection signal G sampled at this time is stored. in this way If the above condition continues, the detection signal G sampled at each time is stored at regular time intervals in the same manner as described above. However, the door was closed and a big vibration occurred. Is larger than the constant value A, the detection signal G sampled at this time is not stored and the next sampling operation is started after delaying for a predetermined time. The delay time in this case is the same as the time required to store the detection signal, so that the next sampling timing does not shift.

By performing such an operation, the sampling value becomes
It becomes a thing ignoring a large body vibration. Therefore, since the vibration exciter 2 is controlled by this sampling value, it is not possible to prevent a large vibration due to the door being closed, but after this large vibration, the vibration exciter 2 is inadvertently operated to increase the vibration. Absent. After all, vibration reduction can be realized as a whole.

Next, the operation shown in FIG. 6 will be described. First, the detection signal G and its differential signal are input. This time Is smaller than the constant value A, the detection signal G sampled at this time is delayed for a predetermined time and then stored. in this way If the above condition continues, the detection signal G sampled at each time is stored at regular time intervals in the same manner as described above. However, the door was closed and a big vibration occurred. Is larger than a constant value A, the detection signal G sampled at this time is not stored and the following operation is performed. That is, the error between the value of the current detection signal and the value of the previous detection signal is obtained, and the value obtained by adding the value of the current detection signal to 50% of this error value is stored. Note that In this case, the reason for delaying the storage is to match the sampling timing.

By performing such an operation, the sampling value becomes
It will be a little added to the large body vibration. Therefore, since the vibration exciter 2 is controlled by this sampling value, it is possible to prevent even a large vibration due to the closing of the door, and after the large vibration, the vibration exciter 2 is inadvertently operated to increase the vibration. There is no such thing. After all, vibration reduction can be realized as a whole.

According to the present invention as specifically described in connection with the above embodiments, the overall vehicle body vibration can be reduced without further increasing the vibration after a large vibration occurs when the door is closed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vehicle schematically showing the mounting state of a vibration exciter, FIG. 2 is a block diagram of a vehicle body vibration reducing device, FIG. 3 is a flow chart showing a control process, and FIG. Block diagrams showing an embodiment, FIGS. 5 and 6 are flowcharts showing the operation. In the drawing, 2 is an exciter, B is a vehicle body, E is an engine, 3 is a vehicle speed sensor, 4 is an engine speed sensor, 5 is an acceleration sensor, 6 is an ignition pulse generator, 8 is a differentiation circuit, and 10 is a differential circuit. A phase controller, 12 is a gain controller, and 13 is a controller.

Claims (2)

[Claims] 1. A vibration exciter attached to a vehicle body for generating additional vibration to the vehicle body, and a vehicle body vibration at a position where acceleration due to the vehicle body vibration is detected and the vehicle body vibration is to be reduced or at the same position. An acceleration sensor arranged at any detectable position, and the detection signal of the acceleration sensor is input and stored as a sampling value at fixed time intervals, and the phase and gain of the frequency signal of the vehicle body vibration caused by the engine vibration are stored in the engine. A control means for generating a basic excitation signal by adjusting based on the number of revolutions, and supplying an excitation signal to the exciter, the excitation signal having the phase and gain of the basic excitation signal adjusted according to the stored sampling value; When the differential value of the detection signal of the acceleration sensor is less than a fixed value, the control means stores the detection signal as a sampling value, and the differential value is Serial body vibration reducing apparatus characterized by moving to the next sampling operation after a delay predetermined time without storing the sampled values in the case of a certain value or more. 2. A vibration exciter attached to a vehicle body for generating additional vibration to the vehicle body, and a vehicle body vibration at a position where acceleration due to the vehicle body vibration is detected and the vehicle body vibration is to be reduced or at the same position. An acceleration sensor arranged at any detectable position, and the detection signal of the acceleration sensor is input and stored as a sampling value at fixed time intervals, and the phase and gain of the frequency signal of the vehicle body vibration caused by the engine vibration are stored in the engine. A control means for generating a basic excitation signal by adjusting based on the number of revolutions, and supplying an excitation signal to the exciter, the excitation signal having the phase and gain of the basic excitation signal adjusted according to the stored sampling value; When the differential value of the detection signal of the acceleration sensor is less than a fixed value, the control means delays the detection signal for a fixed time and then stores it as a sampling value. In addition, when the differential value is equal to or more than the certain value, a value obtained by adding a value obtained by multiplying the difference between the stored previous sampling value and the value of the detection signal by a predetermined reduction coefficient to the previous sampling value is a sampling value. A vehicle body vibration reduction device characterized by being stored as.