JP5061764B2 - Vehicle vibration suppression control device - Google Patents

Description

  The present invention relates to a vibration damping control device for a vehicle such as an automobile, and more particularly to a vibration damping control device that controls a vehicle driving output (driving force or driving torque) to suppress vibration of a vehicle body.

  Vibrations such as pitch and bounce while the vehicle is running are generated by braking / driving force (or inertial force) that acts on the vehicle body during acceleration / deceleration of the vehicle or other external force that acts on the vehicle body. During driving, it is reflected in torque (hereinafter referred to as “wheel torque”) acting between the driving wheel) and the ground road surface. Therefore, in the field of vehicle vibration suppression control, it has been proposed to suppress the vibration of the vehicle body while the vehicle is running by adjusting the wheel torque through the drive output control of the vehicle engine or other drive device. (For example, see Patent Documents 1 and 2). In the vibration suppression control based on such drive output control, when a vehicle acceleration / deceleration request is made using a motion model constructed on the assumption of a dynamic model of so-called unsprung and unsprung vibrations of the vehicle body, When the external force (disturbance) acts on the wheel torque and the wheel torque fluctuates, the pitch bounce vibration generated in the vehicle body is predicted, and the drive output of the vehicle drive device is adjusted so that the predicted vibration is suppressed. The In the case of this type of vibration suppression control, the generation of vibration energy is suppressed by adjusting the source of the force that generates vibration, rather than by absorbing vibration energy generated as in the case of vibration suppression control by the suspension. Therefore, the vibration damping action is relatively quick and the energy efficiency is good. Further, in the vibration damping control based on the drive output control, since the control target is concentrated on the drive output (drive torque) of the drive device, the control adjustment is relatively easy.

In the vibration suppression control device (or drive output control device) that performs the vibration suppression control by the drive output control as described above, as described above, the wheel torque actually generated in the wheel is controlled. Feedback is fed back to the vibration suppression control device as a disturbance, and an adjustment amount of the drive output necessary for vibration suppression due to the disturbance is determined based on wheel torque actually generated in the vehicle. However, sensors that can directly detect the value of the wheel torque while the vehicle is running, such as a wheel torque sensor and a wheel six-component force meter, exclude the test vehicle, etc. due to vehicle design or cost issues. It is not mounted on a normal vehicle. Therefore, in the vibration damping control device as described above, the wheel torque value fed back as a disturbance input is based on other easily detectable parameters such as the wheel speed and the rotational speed of the output shaft of the vehicle drive device. The estimated wheel torque value is used (for example, see Japanese Patent Application No. 2006-284642 by the applicant of the present application).
JP 2004-168148 A JP 2006-69472 A

  In the vibration suppression control by the drive output control as described above, the output of the drive device is changed, but the wheel torque value input to the vibration suppression control device as a disturbance input or the frequency of the vibration component of the estimated value is the vehicle body. When the frequency of the pitch bounce vibration of the vehicle (usually up to about 1 to 5 Hz) is supported, the wheel torque fluctuation due to the drive output fluctuation and the pitch bounce vibration of the vehicle body are reduced or offset each other. Changes in drive output due to vibration suppression control are not reflected in the longitudinal acceleration / deceleration force of the vehicle. However, the wheel torque value input to the vibration suppression control device as the disturbance input or the estimated value thereof includes vibration components that do not substantially contribute to the vibration suppression of the pitch / bounce vibration of the vehicle body in various frequency bands, and the actual (true) There may be a vibration component that is not a fluctuation of the wheel torque value (hereinafter, such vibration is referred to as “noise vibration”). When such noise vibration is input to the vibration suppression control device and reflected in the output of the drive device, it becomes the acceleration / deceleration force of the vehicle, and induces or amplifies vehicle longitudinal vibration, or vibration suppression in the pitch / bounce direction. It may cause deterioration of the effect.

  Regarding the noise vibration in such vibration suppression control, the inventors of the present invention, in the development research so far, in the development research, the noise vibration that induces or amplifies the longitudinal vibration of the vehicle is the vehicle wheel or the structure of the driving device (the tire structure). Due to mass, dimensional or rigidity imbalance or unbalance such as flat spot, output variation between cylinders of engine, resonance of drive system, abnormality of wheel speed or rotation speed sensor used for estimation of wheel torque) It has been found that this is a vibration component that is generated in the wheel torque or the wheel speed used for the estimation thereof or the rotational speed signal of the drive device. According to the knowledge of the inventor of the present invention, the noise vibration as described above is usually caused by adjusting the structure of the wheel or the driving device at the time of manufacturing / assembling of the vehicle or before the shipment. When vibration suppression control is not performed), the vibration is suppressed to a level that does not cause a problem. However, even with such suppressed vibration, vibration in the front-rear direction of the vehicle may be caused through vibration suppression control. Became clear. However, the frequency band of the noise vibration caused by the structure of the vehicle wheel or the drive device is dependent on the vehicle speed, the rotational speed of the output shaft of the drive device, the resonance frequency of the drive system, and can be estimated in advance. Therefore, in Japanese Patent Application No. 2007-071106 filed by the applicant of the present application, the inventors of the present invention set the frequency of such noise vibration components to the vehicle speed, the rotational speed of the output shaft of the drive device, and the resonance frequency of the drive system. The frequency component removing means reduces or removes the estimated noise vibration frequency band component from the control command (driving torque compensation component) to the drive device for vibration suppression control. It is proposed to suppress the induction or amplification of the longitudinal vibration of the motor (however, if the frequency band of noise vibration and pitch bounce vibration overlaps, the amount of fluctuation due to vibration suppression control in the required driving force to the drive unit) Is reduced.)

  However, the noise vibration observed in an actual vehicle is not observed at the time of manufacture / assembly of the vehicle or before shipment, or even if it is suppressed to be small so as not to adversely affect the vibration control. There are also vibrations that are newly generated or increased due to various factors such as aging during use of the vehicle, and noise vibrations that are newly generated or increased during use of such vehicles are also subject to vibration suppression control. It may induce or amplify vehicle longitudinal vibration during execution. In addition, noise vibration of unknown cause may occur during use in a vehicle.

  Thus, one of the main problems of the present invention is that in the vibration damping control apparatus based on the drive output control as described above, the vehicle vibration in the longitudinal direction of the vehicle caused by newly generated or increased noise vibration after the start of use of the vehicle. It is to avoid the generation or amplification of vibration, or the deterioration of the damping effect on the pitch bounce vibration of the vehicle.

  According to the present invention, there is provided a vibration suppression control device that executes vibration suppression control that suppresses vehicle body pitch or bounce vibration by vehicle drive output control, and is based on various parameters observed during vehicle travel. The noise vibration characteristics that cause the vehicle longitudinal vibration during the vibration suppression control are detected, and the adverse effect of the noise vibration on the control output of the vibration suppression control device is reduced based on the detection result. A vibration suppression control device configured as described above is provided.

  The vehicle vibration damping control device according to the present invention has a pitch or bounce vibration amplitude based on a wheel torque acting on a wheel generated at a contact point between a vehicle wheel and a road surface or an estimated value thereof. A drive torque compensator for compensating the drive torque of the vehicle so as to suppress, and further, when input to the drive torque compensator, has a noise frequency number component that generates a drive torque that generates or amplifies vibrations in the front-rear direction in the vehicle. Noise frequency component determination means for determining whether or not the wheel torque or its estimated value is included, and compensation by the drive torque compensator when it is determined that the wheel torque or its estimated value includes the noise frequency component Noise frequency component reduction means for reducing the contribution of the noise frequency component in the drive torque is provided. Here, the “noise frequency component” is a frequency component of noise vibration that does not contribute to damping of the vehicle pitch / bounce vibration but causes vibration in the longitudinal direction of the vehicle.

The vibration damping control device receives the wheel torque value or its estimated value signal as a disturbance input, processes the signal, and compensates for the driving torque, that is, corrects the driving torque (usually for correcting the driving torque). The compensation amount is calculated, and the compensation amount is reflected in the control of the driving device). As already mentioned, in such a vibration damping control device, if noise vibration is superimposed on the wheel torque value input to the disturbance or the signal of the estimated value, the vibration damping control by the vibration damping control device is performed. When this is executed and the fluctuation of the driving output is given, the longitudinal vibration of the vehicle is induced or amplified. Therefore, in the present invention described above, the noise frequency component determination means determines whether or not the noise frequency component is included in the wheel torque or its estimated value, and the generation of the noise frequency component is detected or estimated. In this case, the noise frequency component reducing means reduces the contribution of the noise frequency component in the driving torque compensated by the driving torque compensator, thereby reducing the longitudinal vibration of the vehicle that can be caused by vibration suppression control. An attempt is made to suppress and more preferably prevent its occurrence.

  In one aspect of the above-described apparatus of the present invention, the noise frequency component determination means includes means for specifying the frequency band of the noise frequency component, and when the frequency band of the noise frequency component can be specified, the noise frequency component The reduction means reduces the vibration component in the frequency band of the noise frequency component in the compensation component of the drive torque given from the drive torque compensator to the vehicle drive device, that is, the fluctuation component of the drive torque given by the vibration damping control. You may be supposed to. As a result, only the noise frequency component in the compensation component is reduced, and when there is a torque fluctuation that causes pitch bounce vibration on the wheel, the pitch is reduced or prevented in the manner in which the longitudinal vibration due to the noise frequency component is suppressed or prevented. -The component which suppresses or cancels the component which causes a bounce vibration is reflected, and a favorable damping effect will be acquired.

  In the above aspect, the means for reducing the vibration component in the frequency band of the noise frequency component typically includes a band cut filter that removes the frequency component of the noise vibration or a component in the frequency band other than the frequency component of the noise vibration. It may be a bandpass filter that passes. Further, in the vibration suppression control apparatus, since signal transmission and calculation processing are typically executed according to a linear calculation formula, the vibration component reduction processing in the frequency band of the noise frequency component is performed in the vibration suppression control apparatus. It should be understood that may be performed at any stage during the time the wheel torque value or its estimate is received and the drive torque compensation component is transmitted to the drive. However, it is useless to process a signal including a noise frequency component in the vibration suppression control apparatus, and there may be a calculation error due to the presence of the noise frequency component in the signal. Therefore, it is preferable to compensate the driving torque by reducing the vibration component in the frequency band of the noise frequency component in the signal before being input to the vibration suppression control device, that is, the wheel torque value or its estimated value. The vibration component in the frequency band of the noise frequency component in the component is reduced.

  Further, when the frequency band of the noise frequency component is specified, the noise frequency component determination means is an arbitrary value reflecting the frequency of the wheel torque value (this value is referred to as “wheel torque index value in this specification”). For example, the wheel torque estimated based on the wheel speed, its differential value, the rotational speed of the output shaft of the driving device, its differential value, the wheel speed or the rotational speed of the output shaft of the vehicle driving device. Whether or not a noise frequency component is included in any or all of a value, a longitudinal acceleration of the vehicle, or a compensation component of the driving torque given from the driving torque compensator to the driving device of the vehicle You may be supposed to. (Since any of the above values is associated with the wheel torque value by a linear arithmetic expression, it is a value having a noise frequency component generated in the wheel torque.) The wheel frequency index value actually includes the noise frequency component. It may be detected by performing frequency analysis (for example, FFT) of the wheel torque index value.

  Further, when the frequency band of the noise frequency component is specified as described above, typically, whether or not the frequency band of various vibration components included in the noise frequency component is a function of the vehicle speed of the vehicle. It may be determined whether it is a function of the rotational speed of the output shaft or whether it is unchanged regardless of the running state of the vehicle. As described in the aforementioned Japanese Patent Application No. 2007-071106, according to the development research by the inventor of the present invention, many of the noise vibrations that cause the longitudinal vibrations of the vehicle during the vibration suppression control are Generated due to the structure of the vehicle wheel or the drive, whose frequency depends on the vehicle speed or wheel speed or the rotational speed of the drive (ie is it a function of the wheel speed or the rotational speed of the drive) Or the resonance frequency of the drive system. Therefore, it is highly likely that noise vibrations generated or increased due to a change in the structure of the wheel or driving device in use of the vehicle to be removed by the apparatus of the present invention have the frequency characteristics as described above. . Therefore, also in the device of the present invention, as described above, the noise frequency component includes a component that is a function of the vehicle speed or the rotational speed of the output shaft of the drive device or a frequency band of the invariant (for example, the resonance frequency of the drive system). It may be possible to identify the frequency band of the noise frequency component. (If the noise frequency component is invariant regardless of the driving / running state of the vehicle, it is easy to remove the noise frequency component, but if it is variable, the characteristic or dependency of the frequency band is quickly identified. This is usually difficult if the processing speed of the processing device is not very high, but as described above, it is aimed at whether it is a function of the vehicle speed or the rotational speed of the output shaft of the drive device. By trying to specify, even if the driving / running state of the vehicle changes, the band of the noise frequency component can be easily specified.)

Thus, in the configuration described above, the vibration component when it is determined to contain a component of the frequency band Ru function der of the vehicle speed of the vehicle in the noise frequency components, which are reduced at the noise frequency component reducing means Is determined as a function of the vehicle speed of the vehicle, and when it is determined that the noise frequency component includes a component of the frequency band that is a function of the rotational speed of the output shaft of the drive device, the noise frequency component The frequency band of the vibration component that is reduced in the reduction means may be determined as a function of the rotational speed. Then, when it is determined that the noise frequency component includes a vibration component whose frequency band is unchanged, the vibration component of the determined noise frequency component whose frequency band is unchanged may be reduced.

  It should be noted that whether the noise frequency component includes a vibration component that is a function of the vehicle speed of the vehicle or the rotational speed of the drive output shaft, or an invariant vibration component, and a specific frequency component corresponding to each It should be understood that any one or two of the reduction or removal may be performed. In the above configuration, when the noise frequency component includes a vibration component that the noise frequency component determination unit cannot specify the frequency band, or the frequency band of the noise frequency component specified by the noise frequency component determination unit is When it overlaps with the frequency of the pitch or bounce vibration to be suppressed by the vibration suppression control device, it is difficult to reduce or eliminate only the noise frequency component, so the noise frequency component reducing means reduces the control gain of the compensation component of the driving torque. That is, the absolute value of the compensation component or its command value is reduced (in some cases, the compensation component is set to 0), and the occurrence or amplification of the longitudinal vibration of the vehicle due to the vibration suppression control is suppressed. Good. (However, in that case, the damping effect is also reduced.)

  By the way, as already mentioned, abnormal or undesirable vibrations that cause noise frequency components that were suppressed during the manufacture / assembly of the vehicle or before its shipment are caused by the structure of the wheel or the drive unit in use of the vehicle. It is thought that it appears newly or increases due to the change with time. And, since the appearance or increase time is considered to depend on the usage amount of the wheel or the driving device, the usage amount of the vehicle wheel or the driving device is monitored, and when the usage amount exceeds a predetermined value, the noise frequency component Can be presumed as having occurred. Therefore, in another aspect of the above-described apparatus of the present invention, the noise frequency component determining means is configured such that the noise frequency number component is the wheel torque or its torque when the usage amount of the vehicle wheel or the driving device exceeds a predetermined value. You may come to estimate that it is contained in an estimated value. In this case, the configuration for detecting the presence of the noise frequency component may be omitted, and thus the effort or cost for designing, adjusting, and manufacturing the apparatus can be reduced.

In the above aspect, the usage amount of the vehicle wheel or the driving device monitored for estimating the generation of the noise frequency component may be, for example, a vehicle travel distance, a wheel torque value or an estimated value thereof, or a driving torque compensation. May be the number of inversions of the compensation component of the driving torque applied from the unit to the driving device of the vehicle (the wheel or the driving device is burdened each time it is inverted). In addition, when a vehicle wheel or a drive device is used and the structure or characteristics of each component of the vehicle changes over time, the compensation component of the drive torque, that is, the target value of the wheel torque (when there is no vehicle drive request) ) And the actual value of the wheel torque. Therefore, the ratio of the driving torque compensation component to the wheel torque value or its estimated value in a predetermined period may be referred to as the amount of use of the vehicle wheel or the driving device. (Looking at the ratio of a given period, the target value and the actual value may have a control delay or a transient shift, so the instantaneous value accurately determines the amount of use of the vehicle wheel or drive unit. (Note that the predetermined period is selected when there is no vehicle drive request.)

  In general, according to the present invention, in the operation of a vibration suppression control device that suppresses pitch / bounce vibration of a vehicle by drive output control, the vehicle body is moved in the front-rear direction along with execution of drive torque control for vibration suppression control. The mechanism of the vibration phenomenon is studied, and at least a part of the longitudinal vibration of such a vehicle body can be caused by the frequency component of the noise vibration included in the wheel torque value input as the disturbance input or the estimated value. In addition, noise vibration that is not observed or does not cause a problem at the time of manufacture / assembly or shipment of the vehicle may occur or increase after the start of use of the vehicle. This has been done by finding that vibrations can be induced or amplified. In particular, the vibration suppression control device of the present invention detects or estimates the presence of noise vibration that occurs or amplifies after the start of use of the vehicle, and suppresses longitudinal vibration of the vehicle body due to noise vibration (ideally, completely (Stop).

  In the vibration damping control device of the present invention, in a mode in which the frequency component of the noise vibration is removed from the compensation component for the vibration damping control of the drive torque, the wheel torque value that exhibits the damping effect of the pitch or bounce vibration Or, the frequency component of the estimated value is input to the vibration suppression control device with a gain that can effectively exhibit the vibration suppression action, and is good (unless the noise frequency component matches the frequency of the pitch or bounce vibration). It should be understood that the drive torque control can be executed with a control amount that provides a sufficient vibration damping effect. The various aspects listed in the means for solving the problem may be selectively realized in one vibration suppression control device according to the manufacturing cost of the vehicle, etc. Alternatively, all of the listed modes may be realized by one vibration suppression control device. In addition, in the apparatus of the present invention, when the apparatus itself can detect the presence or absence of a noise frequency component or can detect a frequency band in a state where the apparatus is incorporated in a vehicle, the noise frequency component is estimated in advance. Regardless of whether it is possible or not, the contribution of noise frequency components can be reduced. Therefore, it is not necessary to set in advance the calculation process of the frequency component to be removed or its band as proposed in Japanese Patent Application No. 2007-071106 (however, the calculation process of the frequency component to be removed or its band is not required). Since the noise vibration for the frequency band is surely removed and the accuracy is improved, the configuration proposed in Japanese Patent Application No. 2007-071106 is used in one vibration suppression control device. (See also the column of the embodiment.)

  Further, it should be noted that, in the vibration suppression control device of the present invention, noise frequency components due to the structure of the vehicle wheel or the drive device are excluded (or reduced) from the control of the drive torque. There is no need to tighten the tolerances of the dimensions of the parts that make up the vehicle wheel tires, sensors, or drive devices only for the purpose of vibration suppression control, or to increase the precision and durability of the settings of each part. Therefore, the cost and labor for vehicle manufacture and adjustment can be reduced.

  Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention.

  The present invention will now be described in detail with reference to a few preferred embodiments with reference to the accompanying drawings. In the figure, the same reference numerals indicate the same parts.

Configuration of Device FIG. 1 (A) a vehicle such as an automobile in which the preferred embodiment of the vibration damping control device is mounted of the present invention is schematically shown. In the figure, the vehicle 10 having the left and right front wheels 12FL and 12FR and the left and right rear wheels 12RL and 12RR is driven in the normal manner according to the depression of the accelerator pedal 14 by the driver. A drive device 20 that generates torque is mounted. In the illustrated example, the driving device 20 is configured such that driving torque or rotational driving force is transmitted from the engine 22 to the rear wheels 12RL and 12RR via the torque converter 24, the automatic transmission 26, the differential gear device 28, and the like. Composed. However, an electric type in which an electric motor is used instead of the engine 22 or a hybrid type driving device having both an engine and an electric motor may be used. The vehicle may be a four-wheel drive vehicle or a front wheel drive vehicle. Although not shown for the sake of simplicity, the vehicle 10 is provided with a braking system device that generates a braking force on each wheel and a steering device for controlling the steering angle of the front wheels or the front and rear wheels, as in a normal vehicle. It is done.

  The operation of the driving device 20 is controlled by the electronic control device 50. The electronic control unit 50 may include a microcomputer having a CPU, a ROM, a RAM, and an input / output port device, which are connected to each other by a bidirectional common bus, and a driving circuit. The electronic control unit 50 includes a signal Vwi (i = FL, FR, RL, RR) representing a wheel speed from a wheel speed sensor 30i (i = FL, FR, RL, RR) mounted on each wheel, and G Signals such as the longitudinal acceleration α of the vehicle from the sensor 32, the rotational speed ne of the engine, the rotational speed no of the transmission, and the accelerator pedal depression amount θa from the sensors provided in each part of the vehicle are input. In addition to the above, it should be understood that various detection signals for obtaining various parameters necessary for various controls to be executed in the vehicle of the present embodiment may be input. As schematically shown in more detail in FIG. 1B, the electronic control unit 50 operates the drive control unit 50a for controlling the operation of the drive unit 20 and the operation of the braking unit (not shown). You may comprise from the braking control apparatus 50b to control. In the braking control device, electric signals in the form of pulses are generated from the wheel speed sensors 30FR, FL, RR, RL of each wheel, which are sequentially generated every time the wheel rotates by a predetermined amount, and the sequential control is performed. The rotational speed of the wheel is calculated by measuring the time interval at which the pulse signal input to the wheel arrives, and the wheel speed value is calculated by multiplying this by the wheel radius. Then, as described below, the wheel speed value is transmitted to the drive control device 50a in order to calculate a wheel torque estimated value. The calculation from the wheel rotation speed to the wheel speed may be performed by the drive control device 50a. In this case, the wheel rotation speed is given from the braking control device 50b to the drive control device 50a.

In the drive control device 50a, the target output torque (required drive torque) of the drive device requested by the driver based on the accelerator pedal depression amount θa is determined based on the drive request from the driver. However, in the drive control device of the present invention, the required drive torque is corrected to execute the pitch / bounce vibration damping control of the vehicle body by the drive torque control, and the control command corresponding to the corrected required drive torque Is applied to the drive device 20. In such pitch / bounce vibration damping control, generally speaking,
(1) Calculation of the estimated wheel torque of the driving wheel by the force acting between the driving wheel and the road surface,
(2) Pitch / bounce vibration state quantity calculation using a body vibration model,
(3) Calculation of the correction amount (required drive torque compensation component) of the wheel torque that suppresses the pitch / bounce vibration state quantity, and compensation or correction of the required drive torque based on this calculation are executed. As will be described later, the estimated wheel torque value (1) is calculated based on the wheel speed value of the drive wheel (or the wheel rotation speed of the drive wheel) received from the braking control device 50b or the engine rotation speed ne. It's okay. It should be understood that the vibration damping control device of the present invention is realized in the processing operations (1) to (3).

FIG. 2 (A) shows an example of a drive torque control configuration in which the vehicle body pitch / bounce vibration damping control is performed . In the vehicle body 10 as described above, bounce vibration in the vertical direction (z direction) of the center of gravity Cg of the vehicle body and pitch vibration in the pitch direction (θ direction) around the center of gravity of the vehicle body can occur. Further, when an external force or torque (disturbance) acts on the wheels from the road surface while the vehicle is running, the disturbance is transmitted to the vehicle, and vibrations in the bounce direction and the pitch direction may also occur in the vehicle body. Therefore, in the illustrated embodiment, a motion model of the pitch / bounce vibration of the vehicle body is constructed, and in that model, the required drive torque (value converted into wheel torque) and the current wheel torque (estimated). ) And the rate of change dz / dt, dθ / dt, that is, the state variable of the body vibration is calculated, and the state variable obtained from the model converges to zero. That is, the drive torque of the drive device is adjusted so that the pitch / bounce vibration is suppressed (the required drive torque is corrected).

  FIG. 2B schematically shows the configuration of the drive torque control in the embodiment of the present invention in the form of a control block (in addition, the operation of each control block is (except for C0 and C3). It is executed by either the drive control device 50a or the braking control device 50b of the electronic control device 50). Referring to FIG. 2 (B), in the drive torque control according to the embodiment of the present invention, generally speaking, a drive controller for giving a drive request of the driver to the vehicle, and suppressing the pitch / bounce vibration of the vehicle body. And a vibration suppression controller for correcting the driving request of the driver. In the drive controller, after the driver's drive request, that is, the accelerator pedal depression amount (C0) is converted into the required drive torque in a normal manner (C1), the required drive torque is driven. It is converted into a control command for the device (C2) and transmitted to the drive device (C3). [The control command includes a target throttle opening for a gasoline engine, a target fuel injection amount for a diesel engine, a target current amount for a motor, and the like. ]

  On the other hand, the vibration damping controller includes a feedforward control part (compensation component calculation part) and a feedback control part. The feedforward control portion has a so-called optimum regulator configuration, and here, as described below, a value obtained by converting the required driving torque of C1 into wheel torque (driver required wheel torque Tw0) is the pitch of the vehicle body. The input is input to the motion model portion (C4) of the bounce vibration. In the motion model portion (C4), the response of the state variable of the vehicle body to the input torque is calculated, and the driver requested wheel torque that converges the state variable to the minimum , That is, the compensation component U (= KX) is calculated (C5). In the feedback control portion, the wheel torque estimator (C6) calculates a wheel torque estimated value Tw as will be described later, and the wheel torque estimated value is calculated based on the feedback control gain FB (in the driving model). After the driver requested wheel torque Tw0 and the gain for adjusting the balance of contribution between the wheel torque estimated value Tw) are multiplied, the disturbance input is added to the requested wheel torque and input to the motion model portion (C4). Thereby, the compensation component of the required wheel torque against the disturbance is also calculated. The compensation component of the required wheel torque of C5 is converted into a unit of the required torque of the driving device and transmitted to the adder (C1a). Thus, the required driving torque is corrected so that pitch bounce vibration does not occur. Thereafter, it is converted into a control command (C2) and given to the driving device (C3).

  As the input signal of the wheel torque estimator in the feedback control section, a signal representing the wheel speed r · ω, the wheel rotation speed ω, or the engine rotation speed ne (or the transmission rotation speed no) is input. However, in the apparatus of the present invention, these input signals, as will be described in more detail later, are band-cut filters that remove frequency components of noise vibrations that do not contribute to damping of vehicle body pitch / bounce vibrations ( To the wheel torque estimator via C7).

  The frequency band of the component removed by the band cut filter is determined by a function of a vehicle speed or a rotational speed which is determined experimentally or theoretically in advance or at the start of use of the vehicle, It may be determined based on the resonance frequency of those suspension devices (not shown). However, in an actual vehicle, after the start of use, noise vibration as described above newly appears, or vibration components that have been suppressed to a level that does not cause a problem before the start of use (and are therefore removed in advance). Not so prepared) may increase. Therefore, in the present embodiment, based on the wheel speed r · ω or the rotational speed ω of the wheel, the engine rotational speed ne (or the rotational speed no of the transmission) and / or the longitudinal acceleration value α from the G sensor, A vibration detector C8 for detecting the presence or absence of noise vibration mixed in the wheel torque value is provided. The vibration detector C8 detects the frequency band of the noise vibration, as will be described in more detail later, and when the frequency component of the noise vibration can be removed by the band cut filter, the component removed by the band cut filter When it is determined that the frequency component of noise vibration cannot be removed, the feedback control gain, the output gain of the band cut filter C7, or the drive torque (or required wheel torque) sent to the drive controller It has a function of reducing the control gain of the compensation component.

  Furthermore, the possibility of a new appearance or increase of noise vibration after the start of use of the vehicle increases as the amount or burden of use of the vehicle wheel or drive device increases. Therefore, in this embodiment, the control gain of the compensation component of the drive torque transmitted from the vibration suppression controller to the drive controller is referred to with reference to the usage amount (travel history, etc.) of the vehicle wheel or the drive device. A compensation reducer C9 for reduction may be provided. As will be described later, the usage amount of the vehicle wheel or the driving device includes the vehicle travel distance, the number of inversions of the wheel torque estimated value or the driving torque compensation component, and the ratio or difference between the driving torque compensation component and the wheel torque estimated value. May be referred to. (The compensation reducer functions as a noise frequency component judging means for estimating the presence or absence of noise vibration with reference to the amount of use of the vehicle wheel or drive device, and the noise frequency component in the drive torque by reducing the control gain. It has a function as a noise frequency component reducing means for reducing the contribution of.

Principle of Vibration Suppression Control In the vibration suppression control in the embodiment of the present invention, as already mentioned, first, assuming the dynamic motion model in the bounce direction and the pitch direction of the vehicle body, the driver requested wheel A state equation of state variables in the bounce direction and the pitch direction is input with the torque Tw0 and the estimated wheel torque value Tw (disturbance) as inputs. Then, from this state equation, the input (torque value) for converging the bounce and pitch state variables to 0 is determined using the theory of the optimal regulator, and the required drive torque is corrected based on the obtained torque value. (When the state variable in the pitch bounce direction is 0, it can be said that the vehicle is in the normal state. Therefore, the “correction” of the required drive torque here is the pitch bounce direction in the drive torque control. This can be said to be “compensation” of the driving torque for making the vehicle state normal.

ここに於いて、Ｌｆ、Ｌｒは、それぞれ、重心から前輪軸及び後輪軸までの距離であり、ｒは、車輪半径であり、ｈは、重心の路面からの高さである。なお、式（１ａ）に於いて、第１、第２項は、前輪軸から、第３、４項は、後輪軸からの力の成分であり、式（１ｂ）に於いて、第１項は、前輪軸から、第２項は、後輪軸からの力のモーメント成分である。式（１ｂ）に於ける第３項は、駆動輪に於いて発生している車輪トルクＴ（＝Ｔｗ０＋Ｔｗ）が車体の重心周りに与える力のモーメント成分である。 As a dynamic motion model in the bounce direction and pitch direction of the vehicle body, for example, as shown in FIG. 3A, the vehicle body is regarded as a rigid body S of mass M and moment of inertia I, and the rigid body S has an elastic modulus kf. And a front wheel suspension with a damping rate cf, and a rear wheel suspension with an elastic modulus kr and a damping rate cr (car body sprung vibration model). In this case, the motion equation in the bounce direction and the motion equation in the pitch direction of the center of gravity of the vehicle body are expressed as the following Equation 1.

Here, Lf and Lr are distances from the center of gravity to the front wheel shaft and the rear wheel shaft, respectively, r is a wheel radius, and h is a height of the center of gravity from the road surface. In Equation (1a), the first and second terms are components of force from the front wheel shaft, and the third and fourth terms are components of force from the rear wheel shaft. In Equation (1b), the first term Is the moment component of the force from the front wheel shaft, and the second term is the force from the rear wheel shaft. The third term in the equation (1b) is a moment component of the force that the wheel torque T (= Tw0 + Tw) generated in the drive wheel gives around the center of gravity of the vehicle body.

であり、行列Ａの各要素a1-a4及びb1-b4は、それぞれ、式（１ａ）、（１ｂ）のｚ、θ、ｄｚ／ｄｔ、ｄθ／ｄｔの係数をまとめることにより与えられ、
a1=-(kf+kr)/M、a2=-(cf+cr)/M、
a3=-(kf・Lf-kr・Lr)/M、a4=-(cf・Lf-cr・Lr)/M、
b1=-(Lf・kf-Lr・kr)/I、b2=-(Lf・cf-Lr・cr)/I、
b3=-(Lf²・kf+Lr²・kr)/I、b4=-(Lf²・cf+Lr²・cr)/I
である。また、ｕ(t)は、
ｕ(t)＝Ｔ
であり、状態方程式（２ａ）にて表されるシステムの入力である。従って、式（１ｂ）より、行列Ｂの要素p1は、
p1=h/(I・r)
である。 The above formulas (1a) and (1b) are expressed as (linear) as shown in the following formula (2a) with the vehicle body displacements z and θ and their change rates dz / dt and dθ / dt as the state variable vector X (t). It can be rewritten in the form of a system state equation.
dX (t) / dt = A · X (t) + B · u (t) (2a)
Here, X (t), A, and B are respectively

And each element a1-a4 and b1-b4 of the matrix A is given by combining the coefficients of z, θ, dz / dt, dθ / dt in the equations (1a) and (1b), respectively.
a1 =-(kf + kr) / M, a2 =-(cf + cr) / M,
a3 =-(kf ・ Lf-kr ・ Lr) / M, a4 =-(cf ・ Lf-cr ・ Lr) / M,
b1 =-(Lf ・ kf-Lr ・ kr) / I, b2 =-(Lf ・ cf-Lr ・ cr) / I,
b3 =-(Lf ²・ kf + Lr ²・ kr) / I, b4 =-(Lf ²・ cf + Lr ²・ cr) / I
It is. U (t) is
u (t) = T
And is an input of the system represented by the state equation (2a). Therefore, from equation (1b), the element p1 of the matrix B is
p1 = h / (I ・ r)
It is.

In the equation of state (2a)
u (t) = − K · X (t) (2b)
Then, the equation of state (2a) is
dX (t) / dt = (A-BK) .X (t) (2c)
It becomes. Accordingly, the initial value X ₀ (t) of X (t) is set as X ₀ (t) = (0,0,0,0) (assuming that there is no vibration before torque is input). ), The gain that converges the magnitude of X (t), that is, the displacement in the bounce direction and the pitch direction and its time change rate, to 0 when the differential equation (2c) of the state variable vector X (t) is solved When K is determined, a torque value u (t) for suppressing pitch bounce vibration is determined.

The gain K can be determined by using a so-called optimal regulator theory. According to this theory, a quadratic evaluation function J = 1/2 · ∫ (X ^T QX + u ^T Ru) dt (3a)
(Integral range is 0 to ∞)
When the value of is the minimum, the matrix K that minimizes the evaluation function J by the stable convergence of X (t) in the state equation (2a) is
K = R ⁻¹・ B ^T・ P
It is known to be given by Where P is the Riccati equation
^{-dP / dt = A T P +} PA + Q-PBR -1 B T P
Is the solution. The Riccati equation can be solved by any method known in the field of linear systems, which determines the gain K.

などと置いて、式（３ａ）に於いて、状態ベクトルの成分のうち、特定のもの、例えば、ｄｚ／ｄｔ、ｄθ／ｄｔ、のノルム（大きさ）をその他の成分、例えば、ｚ、θ、のノルムより大きく設定すると、ノルムを大きく設定された成分が相対的に、より安定的に収束されることとなる。また、Ｑの成分の値を大きくすると、過渡特性重視、即ち、状態ベクトルの値が速やかに安定値に収束し、Ｒの値を大きくすると、消費エネルギーが低減される。 Note that Q and R in the evaluation function J and Riccati equation are respectively a semi-positive definite symmetric matrix and a positive definite symmetric matrix, which are weight matrices of the evaluation function J determined by the system designer. For example, in the case of the motion model considered here, Q and R are

In Equation (3a), a specific one of the components of the state vector, for example, the norm (magnitude) of dz / dt, dθ / dt, and the other components, for example, z, θ If the value is set larger than the norm of, the component having the larger norm is converged relatively stably. Further, when the value of the Q component is increased, the transient characteristics are emphasized, that is, the value of the state vector quickly converges to a stable value, and when the value of R is increased, the energy consumption is reduced.

  In the actual operation of the vibration suppression control device, as shown in the block diagram of FIG. 2B, in the motion model C4, the differential equation of Expression (2a) is solved using the torque input value. Thus, the state variable vector X (t) is calculated. Next, at C5, the value U () obtained by multiplying the state vector X (t), which is the output of the motion model C4, by the gain K determined to converge the state variable vector X (t) to 0 or the minimum value as described above. t) is subtracted from the required driving torque in the adder (C1a) (converted to the torque of the driving device) (for the calculation of the movement model C4, it is also fed back to the torque input value of the movement model C4). (Status feedback)). The system represented by equations (1a) and (1b) is a resonant system, and for any input, the value of the state variable vector is substantially about the natural frequency of the system. Only frequency components in a band having spectral characteristics are obtained. Thus, by constructing such that U (t) (converted value) is subtracted from the required drive torque, a component of the natural frequency of the system, that is, pitch bounce vibration is generated in the vehicle body. The component is corrected, and the pitch bounce vibration in the vehicle body is suppressed. When a fluctuation that causes pitch bounce vibration occurs in Tw (disturbance) transmitted from the wheel torque estimator, a required torque command that is input to the drive device so that the vibration due to the Tw (disturbance) converges. Is modified using -U (t).

  The resonance frequency of vibration in the pitch bounce direction of a vehicle such as a normal automobile is approximately 1 to 2 Hz, and the speed of vibration in such a frequency band is a control response of wheel torque to a request command in the current vehicle. Is a level at which a torque disturbance in the wheel can be detected and a compensation amount for the disturbance can be reflected in the driving torque of the wheel. Therefore, the disturbance torque generated in the wheel that can cause pitch bounce vibration and the pitch bounce vibration caused by this are offset by the fluctuation of the drive torque output by the drive device by correcting the required drive torque by vibration suppression control. Become.

ここに於いて、xf、xrは、前輪、後輪のばね下変位量であり、mf、mrは、前輪、後輪のばね下の質量である。式（４ａ）−（４ｂ）は、ｚ、θ、xf、xrとその時間微分値を状態変数ベクトルとして、図３（Ａ）の場合と同様に、式（２ａ）の如き状態方程式を構成し（ただし、行列Ａは、８行８列、行列Ｂは、８行１列となる。）、最適レギュレータの理論に従って、状態変数ベクトルの大きさを０に収束させるゲイン行列Ｋが決定される。実際の制振制御は、図３（Ａ）の場合と同様である。 As a dynamic motion model in the bounce direction and the pitch direction of the vehicle body, for example, as shown in FIG. 3B, in addition to the configuration of FIG. A model that takes into account the above (vehicle body sprung / lower vibration model) may be employed. Assuming that the tires for the front wheels and the rear wheels have the elastic moduli ktf and ktr, respectively, the equation of motion in the bounce direction and the equation of motion in the pitch direction of the center of gravity of the vehicle body are as understood from FIG. The following equation 4 is expressed.

Here, xf and xr are unsprung displacement amounts of the front and rear wheels, and mf and mr are unsprung masses of the front and rear wheels. Equations (4a)-(4b) form a state equation as shown in Equation (2a), similarly to the case of FIG. 3A, with z, θ, xf, xr and their time differential values as state variable vectors. (However, the matrix A has 8 rows and 8 columns, and the matrix B has 8 rows and 1 column.) According to the theory of the optimal regulator, the gain matrix K that converges the magnitude of the state variable vector to 0 is determined. Actual vibration suppression control is the same as in the case of FIG.

Calculation of estimated wheel torque In the feedback control part of the vibration damping controller shown in FIG. 2 (B), the wheel torque input as disturbance to the feedforward control part is ideally provided with a torque sensor for each wheel. It only has to be detected actually. However, as already mentioned, it is difficult to provide a torque sensor for each wheel of a normal vehicle, so the wheels estimated by the wheel torque estimator (C6) from other detectable values in the running vehicle. A torque estimate is used.

The wheel torque estimated value Tw is typically obtained by using a wheel rotational speed ω obtained from a wheel speed sensor of a driving wheel or a time derivative of a wheel speed value r · ω,
Tw = M · r ² · dω / dt (5)
Can be estimated. Here, M is the mass of the vehicle, and r is the wheel radius. [If the sum of the driving forces generated at the contact points of the driving wheels on the road surface is equal to the overall driving force MG (G is acceleration) of the vehicle, the wheel torque Tw is
Tw = M · G · r (5a)
Given in The acceleration G of the vehicle is obtained from the differential value of the wheel speed r · ω,
G = r · dω / dt (5b)
Therefore, the wheel torque is estimated as shown in Equation (5). ]

In addition, when an abnormality occurs in the wheel speed sensor and the detection accuracy of the wheel speed is deteriorated, the accuracy of the wheel torque estimated value according to the equation (5) is also deteriorated. Alternatively, the wheel speed may be calculated from the rotational speed of the drive device. When the rotational speed ne of the output shaft of the engine or motor of the driving device is used, the wheel rotational speed of the driving wheel is
ωe = ne x transmission (transmission) gear ratio x differential (differential gear) gear ratio (8)
Given by. When using the rotational speed no of the output shaft of the transmission,
ωo = no x differential gear ratio (9)
Given by. Then, the estimated value of the wheel rotational speed ω of the drive wheel in Expression (8) or (9) is substituted into Expression (5), and the estimated wheel torque value is calculated.

The calculation of the estimated wheel torque value according to the equation (8) or (9) may be executed, for example, when any of the following conditions (a) to (d) is satisfied.
(A) When an abnormality occurs in the signal of the wheel speed sensor, and it is determined as “abnormal state”.
(B) When the abnormality of the wheel speed sensor is determined in another control device such as ABS, VSC, TRC or the braking control device 50b (FIG. 1B).
(C) When the difference between the wheel speed calculated from the signal from the wheel speed sensor and the wheel speed calculated from the rotational speed of the output shaft of the drive device by equation (8) exceeds a predetermined value for a predetermined period. .
(D) When the difference between the wheel speed calculated from the signal of the wheel speed sensor and the wheel speed calculated from the rotational speed of the output shaft of the transmission by equation (9) exceeds a predetermined value for a predetermined period. .

Mechanism of generation or amplification of vehicle longitudinal vibration by vibration suppression control In actual vehicle wheels, due to the structure of the wheels or driving devices, for example, tire imbalance and engine "cylinder variation" In some cases, torque vibration may occur due to resonance of the drive device and its suspension device, and the vibration of the vehicle may generate vibration in the front-rear direction of the vehicle. Therefore, in an ordinary vehicle, each part of the vehicle is adjusted so as to suppress the vibration of the wheel torque so as to reduce such a longitudinal vibration to an acceptable level at the vehicle design and assembly stage. However, even if the wheel torque vibration is low level, it is input from the disturbance input of the vibration damping control device, and when the driving torque is corrected by this, the longitudinal vibration of the vehicle as described above is amplified. A phenomenon was discovered. In addition, the same phenomenon is not observed at the vehicle design and assembly stage, and vibrations that have been suppressed to such an extent that the drive output is hardly affected are due to aging of each part of the vehicle during use of the vehicle. Can also occur by becoming prominent.

  As already described, the motion model of pitch bounce vibration in the above-described vibration damping control device is a displacement (state vector) at a certain resonance frequency, as can be understood from the equations (1a) and (1b). Is a resonance model in which increases. Accordingly, in the compensation component of the required drive torque calculated by multiplying the state vector X (t) by the gain K, the component whose frequency band is away from the resonance frequency is relatively smaller than the component of the resonance frequency band. Therefore, it seems that the torque vibration component having a frequency deviating from the resonance frequency of the pitch bounce vibration hardly affects the operation of the vibration suppression control device.

  However, the vibration suppression control system is a linear system, and if the vibration component of the wheel torque includes a frequency component higher than the resonance frequency of the pitch bounce vibration, that is, a fast fluctuation component, such a high frequency is included. When a component is input to the vibration suppression control device, a corresponding high frequency component is generated in the required drive torque compensation component even if it is at a low level, and is sent to the drive device as a control command. Then, at the speed of the wheel torque control response to the request command in the current vehicle, the change of the drive torque on the wheel transmitted from the drive device can follow the control command of the high frequency component drive torque. A delay occurs, and the delay in response increases the warp torque instead of canceling the vibration of the wheel torque, thereby amplifying the longitudinal vibration of the vehicle that has been kept below the allowable level. There is a case.

  Further, in the actual detected value or estimated value of the wheel torque of the vehicle, vibrations that are not true wheel torque fluctuations may occur due to the structure or accuracy of the sensor. In this case, regardless of the vibration frequency, the vibration that is not a fluctuation of the true wheel torque is input to the vibration suppression control device, so that the control command for the required drive torque is distorted, and the vibration suppression control is performed. Or the vibration in the front-rear direction of the vehicle will occur (because the wheel torque to be canceled is not actually generated).

  In the present specification, as described above, the vibration component of the wheel torque value that does not contribute to the vibration suppression of the pitch bounce vibration and can cause the generation or amplification of the longitudinal vibration of the vehicle is described as “ This is called “noise vibration”.

  The characteristics of the longitudinal vibration of the vehicle generated or amplified by executing the vibration suppression control as described above depend on the source of noise vibration and the transmission path, and can be classified as follows.

(A) Vehicle Speed Dependent Longitudinal Vibration In the vehicle longitudinal vibration generated or amplified by execution of vibration suppression control, there is a case where a component whose vibration frequency is a function of vehicle speed, that is, a component dependent on vehicle speed is included. is there. Such vehicle speed-dependent vibration components are amplified or generated due to the following factors.

(I) Tire Unbalance In a tire that is actually used for a vehicle wheel, there is a so-called “tire unbalance” such as an unbalance in mass, dimensions or rigidity, or a flat spot. When such tire imbalance exists, the wheel speed or the torque acting on the wheel fluctuates during one rotation of the wheel. Accordingly, if torque fluctuation occurs several times per rotation, the frequency of torque fluctuation is an integral multiple of the wheel rotation frequency, and thus is a function of wheel speed, that is, a function of vehicle speed. Even if the torque fluctuation caused by the tire imbalance that occurs each time the wheel rotates is low enough to cause no problem in the running of a normal vehicle, the wheel speed value by the wheel speed sensor or the rotational speed by the engine rotation sensor. Is input to the vibration suppression control device, the frequency component of the function of the vehicle speed is superimposed on the compensation component of the required drive torque. When the frequency of the torque fluctuation is higher than the resonance frequency of pitch / bounce vibration (about 1 to 2 Hz) and a delay in the control response of the drive torque occurs, the torque fluctuation is amplified as described above. As a result, the drive torque may be controlled.

(Ii) Unbalanced signal output of wheel speed sensor A typical wheel speed sensor has a plurality of serrations (teeth) formed around a rotor that rotates with the wheel, as is known in the art. Each time it passes in front of signal generating means such as an electromagnetic pickup, a pulse is generated from the signal generating means, and the wheel speed value is converted from the frequency of occurrence of the pulses per unit time. In the case of such a format, for example, if the serration intervals on the rotor are uneven or missing, the wheel speed value fluctuates while the wheel makes one revolution. Further, in the wheel speed value obtained by the wheel speed sensor, the wheel speed value may fluctuate during one rotation of the wheel for other reasons such as sensor accuracy. When the estimated wheel torque value based on such wheel speed value is input to the disturbance input of the vibration suppression control device and the required drive torque is corrected by the vibration suppression control, the command value of the required drive torque is obtained. A component having a frequency that is an integral multiple of the rotational frequency of the wheel is generated, and a fluctuation in the driving torque at the frequency is output from the driving device. In this case, the driving torque fluctuates despite the fact that there is no fluctuation in the actual wheel torque, so that the wheel torque fluctuates regardless of the frequency, and the original damping effect is impaired. A vibration in the front-rear direction is generated.

(B) Drive Output Shaft Rotational Speed Dependent Longitudinal Vibration In the vehicle longitudinal vibration generated or amplified by execution of damping control, a component whose vibration frequency is a function of the engine rotational speed, There may be a component that depends on the rotational speed. Such rotational speed-dependent vibration components are amplified or generated due to the following factors.

(I) Variation among engine cylinders In a multi-cylinder engine mounted on a vehicle such as a normal automobile, there is a difference in generated torque or energy loss, that is, variation in each cylinder. The output torque may fluctuate during several revolutions of the output shaft (in the case of four cylinders, once during two or four revolutions), thereby causing longitudinal vibrations in the vehicle. . Even if this “cylinder variation” is at an acceptable level that does not cause a problem in normal driving, torque fluctuations due to cylinder variation occur each time the vibration control device operates and the engine output shaft rotates. When a wheel speed value obtained by the wheel speed sensor or a rotation speed value obtained by the engine rotation sensor is input to the vibration suppression control device, a frequency component that is a function of the engine rotation speed is superimposed on a compensation component for the required drive torque. Even if these torque fluctuations are at a low level, the frequency is a value obtained by dividing the rotational frequency of the engine speed by an integer. Therefore, the resonance frequency of the pitch bounce vibration is usually about 1 to 2 Hz. Therefore, the driving torque may be controlled so that the torque fluctuation due to the variation in the cylinder is amplified.

(Ii) Unbalanced signal output from engine rotational speed (drive output shaft rotational speed) sensor In the engine rotational speed sensor signal output, the engine output shaft rotates once, similar to the wheel speed sensor. In the detected value during this period, unevenness, that is, imbalance may occur. In that case, when the estimated wheel torque estimated based on the rotational speed value is input to the disturbance input of the vibration suppression control device and the required drive torque is corrected by the vibration suppression control, A component having a frequency that is an integral multiple of the rotational frequency of the engine output shaft is generated in the compensation component, and a fluctuation in the driving torque having such a frequency is output from the driving device, thereby generating a longitudinal vibration of the vehicle.

(C) Longitudinal vibration of resonance frequency of drive system mechanism Engine mounted on vehicle, power transmission device for transmitting output torque from engine to drive wheel, and suspension device for suspending these device and drive wheel As will be understood by those skilled in the art, a drive system mechanism including a resonance occurs when a force in a certain frequency band (usually about 7 to 11 Hz) is applied. Torque fluctuations at the resonance frequency occur. Therefore, at the time of designing and assembling a normal vehicle, the structure of each device is adjusted so that such resonance is reduced to a level that does not cause a problem in running of the vehicle. However, when the vibration suppression control device operates and torque fluctuation due to resonance of the drive train mechanism is input to the vibration suppression control device on the wheel speed value by the wheel speed sensor or the rotation speed value by the engine rotation sensor, the resonance frequency Are superimposed on the required drive torque compensation component. In addition, with the use of the vehicle, new resonance vibrations appear due to secular changes in each part of the drive train mechanism, and resonance vibrations that were suppressed to a very small level during assembly / setting adjustment increase. May be superimposed on the required drive torque compensation component. Since the frequency of the drive system resonance is higher than the resonance frequency of pitch / bounce vibration (about 1 to 2 Hz), the influence of the delay in the control response of the drive torque overlaps, and the torque fluctuation of the drive system resonance is amplified. As a result, the drive torque may be controlled.

  Further, when the frequency of the vehicle speed-dependent vibration component or the rotation speed-dependent vibration component (including imbalance of sensor output signals) described in (a) and (b) matches the resonance frequency of the drive system mechanism, The control command of the device includes a component of the resonance frequency of the drive system mechanism, and the drive device purposely generates a vibration output of the resonance frequency of the drive system mechanism, so that the torque fluctuation of the drive system resonance is amplified. Therefore, the longitudinal vibration of the vehicle may increase.

Detection and removal of noise vibrations In order to avoid the occurrence or amplification of longitudinal vibrations of the vehicle due to vibration suppression control as described above, in the vibration suppression control device of the present embodiment, the presence or absence of the occurrence of noise vibrations and the A vibration detector C8 for detecting the frequency band and a band cut filter C7 for removing the detected noise vibration are incorporated. The noise vibration detection process and removal process will be described below.

(A) Detection of noise vibration As already described, a part of the noise vibration can be estimated from the state of the tire, the driving device, and the driving system mechanism during the assembly and adjustment of the vehicle. However, during use or running of the vehicle, the state of the tire, drive device, drive system mechanism or sensor changes, and vibrations in a frequency band other than the frequency predicted during vehicle assembly / adjustment may appear or increase. Alternatively, the predicted frequency band of noise vibration may change. Therefore, in the apparatus of the present embodiment, first, the presence or absence of noise vibration that can be superimposed or superimposed on the estimated wheel torque that is the disturbance input of the vibration suppression controller by the vibration detector C8 and its frequency band. Is detected.

  The presence / absence of noise vibration and the frequency band of the wheel torque estimated value are arbitrary “wheel torque index values Twes” including the frequency component included in the wheel torque estimated value, as already described in the disclosure section of the invention, that is, In addition to the estimated wheel torque value, for example, the wheel speed r · ω, its differential value, the rotational speed ne of the output shaft of the drive device, its differential value, the longitudinal acceleration α of the vehicle, or the compensation component U of the drive torque (It may be a wheel torque unit or a drive torque unit.) Can be detected by frequency analysis. Among these, the rotational speed of the output shaft of the drive device and its differential value can detect noise vibration due to resonance of the drive system mechanism and noise vibration whose frequency depends on the rotational speed of the drive device even when the vehicle is stopped. Further, referring to the longitudinal acceleration of the vehicle, it is possible to detect whether or not the longitudinal vibration is actually generated in the vehicle and its frequency band. A person skilled in the art can arbitrarily select which wheel torque index value to perform the frequency analysis for the detection of noise vibration, and analyze all the wheel torque index values described above to perform noise analysis. The vibration may be detected.

4 and 5 show noise vibration detection processing executed by the vibration detector C8 in the form of a flowchart. Generally speaking, in this process, the following processes (i) to (iii):
(I) detection of vibration spectrum by frequency analysis of wheel torque index value using FFT analysis;
(Ii) detection of a frequency at which the intensity of the vibration spectrum is equal to or greater than a predetermined value;
(Iii) Detecting whether or not the intensity of the vibration spectrum in the frequency band depending on the vehicle speed or the drive output shaft rotational speed is greater than or equal to a predetermined value is executed a plurality of times (for example, 5 times) (data acquisition processing) After storing the detection results of the cycle, from these detection results, the frequency “characteristic” at which a strong amplitude appears in the vibration in the wheel torque index value, that is, whether the frequency band is constant or unchanged, Whether the frequency band is expressed as a function of the vehicle speed or the rotational speed of the output shaft of the drive device, or other than these (vibrations whose frequency is variable but independent of the vehicle speed and rotational speed) Are respectively determined (data determination processing). 4 and 5 may be executed every predetermined period or every predetermined traveling distance while the vehicle is traveling.

(Data acquisition process)
Referring to FIG. 4, first, in the data acquisition process, typically, frequency analysis of the wheel torque index value Twes as described above is executed by FFT analysis in any known manner, and the wheel torque index is obtained. The vibration spectrum I [φ] (φ is the frequency) of the value is calculated (step 10: see FIG. 6A). The vibration spectrum acquisition band may be, for example, 1 Hz to the current rotational frequency of the drive output shaft or a multiple thereof (for example, the number of cylinders of the engine) (hereinafter, the maximum value of the vibration spectrum is φmax and To express.). Since such vibration spectrum may have a large error or variation in results in one signal acquisition / calculation, it is preferably executed a plurality of times (step 20), and the average of each frequency of the plurality of result spectra is obtained. The value is preferably determined as the vibration spectrum I _i [φ] (of the current cycle) (step 30). (Subscript i (for example, i = 1 to imax) is a code representing a cycle of data acquisition processing. Imax corresponds to the number of executions of the data acquisition processing cycle. In the description of FIGS. At the same time, the average value Vxm _i of the vehicle speed and the average value nem _i of the rotational speed of the drive output shaft during the analysis (during the acquisition period of the wheel torque index value data for analysis) are calculated. Remembered. The vehicle speed may be arbitrarily determined based on, for example, a wheel speed value from a wheel speed sensor of a driven wheel, information from GPS, or the like.

When the analysis of the vibration spectrum I _i [φ] of the wheel torque index value is completed, whether or not the intensity value I _i (φ) of the vibration spectrum of each frequency φ exceeds a predetermined value Io, that is,
I _i (φ)> Io (10)
(Step 40), and the determination result is stored in an array κ _i (φ) defined with the frequency φ as a parameter (hereinafter, the array κ _i (φ) is referred to as “spectrum determination array”. Called). In the present embodiment, when equation (10) is satisfied, κ _i (φ) = 1 is set (step 42), and when equation (10) is not satisfied, κ _i (φ) = 0 is substituted. (Step 44). Thus, since the array κ _i (φ) is set to 1 only when the intensity value I _i (φ) exceeds the predetermined value Io, as shown in the left diagram of FIG. A frequency having a large amplitude and a frequency having a small amplitude are first determined. The magnitude of the predetermined value Io may be arbitrarily set experimentally or theoretically, and may be changed as appropriate depending on the type of wheel torque index value. For example, when the longitudinal acceleration of the vehicle is used as the wheel torque index value, the fact that the vibration is detected in the longitudinal acceleration of the vehicle means that the longitudinal vibration of the vehicle has already occurred. It is better to set the size of the predetermined value Io relatively low. On the other hand, when the wheel speed value is used as the wheel torque index value, the wheel speed value is processed through the motion model C4 before being reflected in the output of the driving device, and the frequency component in a band that deviates from the resonance frequency of the motion model C4. Are relatively reduced, so the above criteria may not be so strict.

  Thus, when the above spectrum determination array is defined, it is determined whether or not there is vibration in a frequency band that is a function of the vehicle speed or the rotational speed based on the result (in the first stage, the possibility is It is determined whether or not there is.)

が判定される。（ステップ５２）。式（１１ａ）の値が所定値κｗより大きいとき、Ｎｗｒ［ｋｗ］の帯域に振動が発生していると判定することができる。 First, the vehicle speed-dependent vibration frequency Nw [rot / sec] is given by the following equation.
Nw = kw × Vxm _i [km / hour] /3.6 [(m / sec) / (km / hour)] / 2πRw [m / rot] (11)
Here, Vxm _i and Rw are respectively the average value of the vehicle speed and the wheel radius during the current data acquisition period. kw corresponds to the number of signal fluctuations that occur due to an imbalance in the signal output of the tire or wheel speed sensor during one revolution of the wheel. Then, when κi (φ) of the frequency Nw (given by kw) is 1, there is a possibility that vibration depending on the vehicle speed exists. Therefore, in the determination of the vehicle speed dependency of vibration, the number of fluctuations kw per rotation of the wheel kw (kw is an integer from 1 to kw when Nw reaches the maximum frequency φmax of the vibration spectrum). On the other hand, the frequency band Nwr [kw] is set to Nwr (kw) ± ΔNr (step 50), and the sum of κ _i (φ) in each of the bands Nwr [kw] is not less than a predetermined value κw. No, i.e.

Is determined. (Step 52). When the value of Expression (11a) is larger than the predetermined value κw, it can be determined that vibration is occurring in the Nwr [kw] band.

However, in the case of vibration dependent on the vehicle speed, if the vehicle speed changes, Nw changes. Therefore, it is not possible to determine whether or not the vehicle speed depends only on the calculated value of equation (11a) (FIG. 6). (See the right figure in (A)). Therefore, an array λw _i (kw) is defined with the number of fluctuations kw per rotation of the wheel as a parameter, and when equation (11a) holds, λw _i (kw) = 1, and when equation (11a) does not hold , Λw _i (kw) = 0, and the state of the vibration spectrum of the current cycle is recorded for the first time. Such an arrangement will be used later to detect the presence / absence of vehicle speed-dependent vibration and the frequency band.

が判定される（ステップ６２、７２）。そして、式（１３ａ）又は（１３ｂ）の値が所定値κｅ１、κｅ２より大きいとき、対応する帯域に振動が発生していることとなる。回転速依存性の振動の場合には、回転速が変化すると、Ｎｅ１、Ｎｅ２もするので、車速依存性の検出の場合と同様に、ｋｅ１及びｋｅ２を各々パラメータとした配列λｅ１_ｉ（ｋｅ１）、λｅ２_ｉ（ｋｅ２）を定義し、式（１３ａ）、（１３ｂ）が成立するとき、λｅ１_ｉ＝１、λｅ２_ｉ＝１（ステップ６４、７４）、式（１３ａ）、（１３ｂ）が不成立のとき、λｅ１_ｉ＝０、λｅ２_ｉ＝０（ステップ６６、６８）が設定される。 Frequency Ne of the vibration of the rotation speed-dependent output shaft of the drive unit [rot / sec] of the formula below _{Ne1 = ke1 × nem i [rot} / min] / 60 [(sec / min)] ... (12a)
And Ne2 = 1 / ke2 × nem _i [rot / min] / 60 [(sec / min)] (12b)
Given by. Here, nem _i is the drive output shaft rotation speed during the data acquisition period of the current cycle. ke1 corresponds to the number of signal fluctuations caused by the unbalanced signal output of the rotation speed sensor during one rotation of the drive output shaft rotation speed, and ke2 causes one torque fluctuation. This corresponds to the engine speed up to. Therefore, as in the case of the determination of the vehicle speed dependency, first, for each of ke1 (ke1 is an integer from 1 to ke1 when Ne1 reaches the maximum frequency of the vibration spectrum), the frequency band Ne1r. [Ke1] is set to Ne1r (ke1) ± ΔNr (step 60), and for each of ke2 (ke1 is an integer from 2 to ke2 when Ne2 reaches the minimum frequency of the vibration spectrum) The band Ne2r [ke2] is set to Ne2r (ke2) ± ΔNr (step 70), and the sum of κ _i (φ) in each of the bands Ne1r [ke1] and Ne2r [ke2] is a predetermined value κe1. , Greater than κe2, ie,

Is determined (steps 62 and 72). When the value of the expression (13a) or (13b) is larger than the predetermined values κe1 and κe2, vibration is generated in the corresponding band. In the case of vibration dependent on the rotational speed, if the rotational speed changes, Ne1 and Ne2 are also generated. Therefore, as in the case of detection of the vehicle speed dependence, the array λe1 _i (ke1), with ke1 and ke2 as parameters, respectively. When λe2 _i (ke2) is defined and equations (13a) and (13b) hold, λe1 _i = 1, λe2 _i = 1 (steps 64 and 74), and equations (13a) and (13b) do not hold , Λe1 _i = 0 and λe2 _i = 0 (steps 66 and 68) are set.

Thus, when the data array κ _i (φ), λw _i , λe1 _i , and λe2 _i for frequency analysis is stored, one data acquisition processing cycle is completed. The data acquisition processing cycle is repeated a predetermined number of times (for example, 5 times) (step 80). Note that it is preferable that the vehicle speed and the rotational speed change significantly after the completion of a certain data acquisition processing cycle after the next data acquisition processing cycle is executed. Sex cannot be determined.) Although not shown, after the completion of one cycle, the next cycle may be started when the vehicle speed and the rotational speed each change by a predetermined amount.

(Data judgment processing)
As described above, the data acquisition processing cycle is repeated a predetermined number of times, and in each cycle, a frequency having a strong amplitude is stored, and then the data determination processing is executed. In the data determination process, as already described, the “characteristic” of the frequency at which a strong amplitude appears is determined.

κｉ(φ)は、所定値Ｉｏを超える大きな振幅がある周波数φに於いて、１となるので、κ(φ)は、所定値Ｉｏを超える大きな振幅が検出される頻度の高い周波数φに於いて増大することとなる。そこで、
合算された配列κ(φ)について、
κ(φ)＞κｏ …（１４ｂ）
が成立しているか否かが検査され（κｏは、データ取得処理の繰り返し回数か、それよりも低い任意に設定される所定値であってよい。例えば、繰り返し回数imaxが５回ならば、３。）、条件（１４ｂ）が成立している周波数帯域が、車両の走行・運転状況によらず（図４で検出した振動スペクトルの全てに於いて）、大きな振動を生ずる、即ち、周波数不変のノイズ振動の発生している周波数帯域として認定される（ステップ１１０）。 Specifically, as illustrated in FIG. 5, first, the spectrum determination array κ _i (φ) acquired in each data acquisition processing cycle is added up for each frequency for all φ (step 100: (See the right figure in FIG. 6B). That is,

Since κi (φ) is 1 at a frequency φ having a large amplitude exceeding the predetermined value Io, κ (φ) is at a frequency φ at which a large amplitude exceeding the predetermined value Io is detected. Will increase. there,
For the combined array κ (φ),
κ (φ)> κo (14b)
(Κo may be the number of repetitions of the data acquisition process or a predetermined value set lower than that. For example, if the number of repetitions imax is 5, ), The frequency band in which the condition (14b) is satisfied does not depend on the running / driving conditions of the vehicle (in all of the vibration spectrum detected in FIG. 4), and causes a large vibration, that is, the frequency is unchanged. The frequency band in which noise vibration is generated is certified (step 110).

  In order to set a band cut filter for removing such frequency-invariant noise vibration, it is preferable to detect a lower limit value and an upper limit value of a frequency-invariant noise vibration generation band. Therefore, in step 110, for example, as illustrated in FIG. 6C, whether or not the expression (14b) is satisfied (“Y” in the figure) or not (“N”) is sequentially determined for φ. If the frequency at which the equation (14b) is established is logφ and it is detected that the frequency continues for a predetermined interval (for example, 0.2 or more), the frequency of the equation (14b) is satisfied. The minimum value is recognized as the lower limit of the frequency-invariant vibration band. Thereafter, when it is detected that the state in which Formula (14b) is not established is logφ and continues for a predetermined period or longer (for example, 0.2 or more), the minimum value of the frequency in which Formula (14b) is not established is the frequency invariant. It may be certified as the upper limit of the vibration band. Then, the upper limit value and the lower limit value of the band thus identified are stored as values for setting the boundary of the region to be removed by the band cut filter. However, it should be understood that the method of determining the upper and lower limits of the band is not limited to the above algorithm, and may be appropriately configured by those skilled in the art, and such a case also belongs to the scope of the present invention. In particular, since the resonance frequency of the drive system mechanism is usually 7 to 11 Hz, it is determined whether or not the conditional expression (14b) is established at about 5 to 13 Hz, and the established frequency point. Is equal to or greater than a predetermined number, a band cut filter of a band of 5 to 13 Hz may be set on the assumption that resonance of the drive system mechanism has occurred.

かかる式（１５）のλｗ（ｋｗ）、λｅ１（ｋｅ１）、λｅ２（ｋｅ２）の各値は、それぞれ、式（１１）又は式（１２ａ，ｂ）とにより与えられる周波数を有する（大きな振幅の）振動の発生の頻度が高いほど増大する。従って、大きいなλｗ（ｋｗ）、λｅ１（ｋｅ１）、λｅ２（ｋｅ２）の値を与えるｋｗ、ｋｅ１、ｋｅ２は、式（１１）又は式（１２ａ，ｂ）により与えられる周波数、即ち、車速又は回転速の関数である周波数を有するノイズ振動を与えるパラメータとして認定することができる。そこで、式（１５）のλｗ、λｅ１、λｅ２について、所定値以上であるか否か、即ち、
λｗ（ｋｗ）≧λｗｏ …（１６ａ）
λｅ１（ｋｅ１）≧λｅ１ｏ …（１６ｂ）
λｅ２（ｋｅ２）≧λｅ２ｏ …（１６ｃ）
であるか否かが、全てのｋｗ、ｋｅ１、ｋｅ２について検査される（ステップ１４０）ここで、λｗｏ、λｅ１ｏ、λｅ２ｏは、それぞれ、データ取得処理サイクルの繰り返し回数か、それよりも低い任意に設定される所定値であってよい。例えば、繰り返し回数imaxが５回ならば、３。）そして、上記の条件式（１６ａ〜ｃ）が成立するｋｗ、ｋｅ１、ｋｅ２が、車速又は回転速依存のノイズ振動の周波数を決定するｋｗ、ｋｅ１、ｋｅ２として記憶される（ステップ１４５）。 After the generation frequency of the frequency-invariant vibration is specified as described above, the presence / absence of vibration whose frequency depends on the vehicle speed or the rotational speed and kw, ke1, and ke2 that give the frequency band of the vibration are determined. In this process, first, the values of the arrays λw _i , λe1 _i , and λe2 _i acquired in each data acquisition processing cycle are added for each kw, ke1, and ke2 (step 130). That is,

Each value of λw (kw), λe1 (ke1), and λe2 (ke2) in the equation (15) has a frequency (large amplitude) given by the equation (11) or the equation (12a, b), respectively. It increases as the frequency of occurrence of vibration increases. Therefore, kw, ke1, and ke2 that give large values of λw (kw), λe1 (ke1), and λe2 (ke2) are the frequencies given by equation (11) or equation (12a, b), that is, vehicle speed or rotation. It can be identified as a parameter that gives a noise vibration having a frequency that is a function of speed. Therefore, whether or not λw, λe1, and λe2 in the equation (15) is a predetermined value or more, that is,
λw (kw) ≧ λwo (16a)
λe1 (ke1) ≧ λe1o (16b)
λe2 (ke2) ≧ λe2o (16c)
Are checked for all kw, ke1, and ke2 (step 140), where λwo, λe1o, and λe2o are each arbitrarily set to the number of repetitions of the data acquisition processing cycle or lower. It may be a predetermined value. For example, 3 if the number of repetitions imax is 5. Then, kw, ke1, and ke2 that satisfy the conditional expressions (16a to c) are stored as kw, ke1, and ke2 that determine the frequency of noise vibration depending on the vehicle speed or the rotational speed (step 145).

Thus, when the presence / absence of a vibration that does not change the frequency or depends on the vehicle speed or the rotation speed and the frequency band are specified, it is determined whether or not there is a vibration that is variable in frequency but does not depend on the vehicle speed or the rotation speed. For this purpose, first, in the above processing, the contribution of the frequency invariant vibration and the vibration having a frequency dependent on the vehicle speed or the drive output shaft rotational speed is removed from each value of the spectrum determination array κ _i (φ). (Step 150). In such processing, for example, the vehicle speed or the drive output is calculated from the stored kw, ke1, ke2 and the vehicle speed value Vxm _i and / or the rotational speed nem _i when the vibration spectrum is determined. The frequency band in which the vibration dependent on the rotational speed of the shaft was present is determined again using Equation (11) and / or (12a, b). Thereafter, the value of κ _i (φ) in the frequency band in which the vibration dependent on the determined vehicle speed or drive output shaft rotation speed exists is reset to κ _i (φ) = 0. Further, in the above description, all κ _i (φ) corresponding to the frequency band of frequency invariant vibration is reset to κ _i (φ) = 0. As a result, in the array κ _i (φ), only the array value corresponding to the frequency band in which the frequency variable vibration other than the vibration dependent on the vehicle speed or the drive output shaft rotational speed existed when the vibration spectrum was detected. , Κ _i (φ) = 1.

を演算し（ステップ１６０）、
κ１＜κ_total…（１７ｂ）
が成立しているか否かが判定される（ステップ１６５：κ１は、任意に設定されてよい正の整数である。）。式（１７ａ）の値が大きければ大きいほど、発生周波数が定まらず、しかも車速・回転速の依存性のない振動が多く存在することになる。そこで、条件（１７ｂ）が成立するときには、振動スペクトルの計測中に、周波数が可変であるが、車速にも駆動出力軸回転速にも依存しない振動が、有意な量存在していたことが推定できることとなる。 Therefore, as described above, the total for the reset κ _i (φ), that is,

(Step 160),
κ1 <κ _total (17b)
Is determined (step 165: κ1 is a positive integer that may be set arbitrarily). The larger the value of the expression (17a), the more the vibration that does not depend on the vehicle speed and the rotational speed exists and the generated frequency is not determined. Therefore, when the condition (17b) is satisfied, it is estimated that there is a significant amount of vibration that is variable in frequency but not dependent on the vehicle speed or the drive output shaft rotational speed during measurement of the vibration spectrum. It will be possible.

  When there is vibration with variable frequency that does not depend on the vehicle speed or the drive output shaft rotation speed as described above, the frequency is specified in real time during vibration suppression control, and the wheel torque is pinpointed with a band cut filter. Since it is difficult to remove or reduce the value, if there is a predetermined amount or more of vibration having such frequency characteristics, the control gain of the compensation component of the drive torque by the vibration suppression control is reduced.

(B) Elimination of noise vibration The band cut filter C7 is the detection result of the vibration detector C8, that is, the parameters kw, ke1, ke2 corresponding to the noise vibration depending on the vehicle speed or the rotational speed, and the lower limit of the frequency-invariant vibration band. Before the wheel speed or rotation speed is input to the wheel torque estimator C6, the information on the value and the upper limit value is received and determined based on the detection result of the vibration detector C8 at the wheel speed or rotation speed. Frequency band components (noise frequency components) are removed or reduced. When the detection result of the vibration detector C8 is not available, the kw, ke1, and ke2 values corresponding to noise vibrations that are predicted to occur during vehicle manufacture and assembly, and the lower limit value of the frequency-invariant vibration band, and The upper limit value may be used as the initial value.

The frequency Nw [rot / sec] of the noise vibration that generates or amplifies the vehicle speed-dependent longitudinal vibration is, as described above, the following formula: Nw = kw × Vx [km / hour] /3.6 [(m / sec) / (km / hour)] / 2πRw [m / rot] (18)
Calculated by Here, Vx and Rw are a vehicle speed (may be a current value) and a wheel radius, respectively. Therefore, the removal frequency band [Nw] of the band cut filter for removing the noise vibration dependent on the vehicle speed is a band of a predetermined half-value width ΔNw with Nw as a center (see FIG. A) see). The value of ΔNw, the removal amplitude ratio, and the spectral characteristics (profile shape) of the removal frequency band are theoretically or in consideration of the expected noise vibration amplitude and the response speed of the drive torque to the control command in the vehicle. It may be determined experimentally. Note that there may be a plurality of values of kw that cause noise vibration. In such a case, there are a plurality of removal bands as shown in FIG. The initial value of kw is measured by measuring the tire shape and measuring the signal output of the wheel speed sensor when the vehicle is assembled, or by running the test drive without operating the vibration suppression control device. can do.

The frequency Ne [rot / sec] of the noise vibration that generates or amplifies the longitudinal vibration depending on the rotational speed of the drive output shaft is expressed by the following formula: Ne1 = ke1 × ne [rot / min] / 60 [(sec / min)] (19a)
And Ne2 = 1 / ke2 × ne [rot / min] / 60 [(sec / min)] (19b)
Specified by. Here, ne is the current rotational speed of the drive output shaft. Accordingly, the removal frequency band [Ne1] or [Ne2] of the band cut filter for removing the noise vibration depending on the rotation speed is a predetermined frequency centered on Ne1 and Ne2 with reference to Ne1 and Ne2. The band is set to have a half-value width ΔNe1 or ΔNe2 band (see FIG. 7B). The values of ΔNe1 and ΔNe2, the removal amplitude ratio, and the spectral characteristics of the removal frequency band are theoretically or experimentally considered in consideration of the assumed amplitude of noise vibration and the response speed of the drive torque to the control command in the vehicle. May be determined. There may be a plurality of ke1 and ke2 that give rotation-dependent noise vibration. In this case, as shown in the figure, there are a plurality of removal bands. The initial values of ke1 and ke2 are measured by measuring the signal output of the rotational speed sensor and measuring the torque generated in each cylinder at the time of assembling the vehicle, or without running the vibration suppression control device. Can be measured.

  Regardless of the running / driving state of the vehicle, such as the resonance frequency of the drive system mechanism, the spectral characteristics of the removal frequency band [Nc] for vibrations that do not change in frequency include values between the upper and lower limits of the vibration detector. (FIG. 7C). The removal amplitude ratio or spectrum shape is arbitrarily set theoretically or experimentally in consideration of the assumed amplitude of noise vibration and the response speed of the drive torque to the control command in the vehicle. (In this case, there may be a plurality of removal bands). The frequency-invariant vibration (Nc) removal frequency band may be set so that the resonance frequency of the drive system mechanism measured during vehicle assembly and adjustment is removed as an initial value.

  The above-described band cut filter is a “variable band cut filter” whose removal frequency band is variable according to the detection result of the vibration detector C8, and is known to those skilled in the art using a known digital filter technique or analog filter technique. It may be arbitrarily configured. (In particular, a “fixed band cut filter” having a fixed removal frequency band may be incorporated in order to remove noise vibration at the resonance frequency of the drive system mechanism.)

  By the way, since the frequency of the noise vibration having the generated frequency band depending on the vehicle speed or the rotational speed fluctuates, the frequency band may overlap the frequency band of the pitch bounce vibration. For example, when the vehicle speed is in the low speed range (7 to 35 km / h), the noise vibration frequency at that time is about 1 to 5 Hz. In such a case, it is difficult to discriminate between true wheel torque vibration and vibration that is not (noise vibration due to unbalance of sensor signal output) with a band cut filter. Therefore, in such a case, the control gain may be reduced in order to reduce the control amount caused by the wheel torque estimated value (Tw). In that case, for example, the feedback control gain FB is reduced (the output gain of the band cut filter C7 or the control gain of the compensation component of the driving torque in the compensation reducer C9 may be reduced).

  In FIG. 8, the estimated wheel torque value from which the noise vibration has been removed is calculated using the formula (5) based on the wheel rotational speed value ω (may be the wheel speed value r · ω) and input to the motion model. The calculation processing steps up to are shown in the form of a flowchart. Referring to the figure, first, a band cut filter in which the wheel rotational speed value ω of the drive wheels has a removal frequency band [Nc] for removing frequency invariant vibration as exemplified in FIG. 7C. The frequency component corresponding to the resonance frequency of the drive train mechanism is removed from the wheel rotational speed value ω (step 210). Next, the frequencies Ne1 and Ne2 of the noise vibration depending on the drive output shaft rotational speed ne are calculated by the equations (19a) and (19b) (step 220), and the wheel rotational speed value ω after the processing of step 10 is Ne1 and Ne2. Is passed through a variable band-cut filter in which the removal frequency bands [Ne1] and [Ne2] (FIG. 7B) are determined, and from the wheel rotation speed value ω, noise vibration depending on the drive output shaft rotation speed Are removed (step 230).

Thereafter, the frequency Nw of the noise vibration dependent on the vehicle speed Vx is calculated based on the vehicle speed Vx according to the equation (18) (step 240), and the noise vibration dependent on the vehicle speed Vx is removed based on the calculated frequency Nw. Therefore, the removal frequency band [Nw] of the variable band cut filter is determined (FIG. 7A). Here, when the removal frequency band [Nw] does not overlap with the vibration suppression frequency band [Nt] of the pitch / bounce vibration to be controlled in the vibration suppression control device, for example, 1 to 5 Hz (steps 250 to 252). ), That is,
Nthi <Nwlo (20a) or Nwhi <Ntlo (20b)
Where Nwlo and Nwhi are the lowest and highest frequencies of the removal frequency band [Nw], and Ntlo and Nthi are the lowest and highest frequencies of the vibration suppression frequency band [Nt] of the pitch bounce vibration. 7A, when there are a plurality of removal bands, the equations (20a, b) are checked for the upper and lower limit values of each band.), Wheel rotation after step 230 processing The speed value ω is passed through a band cut filter of the removal frequency band [Nw] (step 260), and a wheel torque estimated value Tw is calculated (step 270) using the equation (5). Thereby, in the estimated wheel torque value, the noise vibration component that generates or amplifies the longitudinal vibration of the vehicle is removed, and the estimated wheel torque value Tw is multiplied by the control gain FB (step 280). , Used to calculate the motion model C4 (FIG. 2B).

On the other hand, when the removal frequency band [Nw] of the variable band cut filter for removing the noise vibration dependent on the vehicle speed Vx overlaps with the vibration suppression frequency band [Nt] of the pitch bounce vibration, that is, Expression (20a) and When none of (20b) is established (steps 250-252), the wheel rotational speed value ω after the processing of step 230 is used as it is for the calculation of the wheel torque estimation value Tw using the equation (5) (step). 275). Accordingly, in this case, since the wheel torque estimated value Tw may include noise vibration dependent on the vehicle speed Vx, the reduced control gain FBx is multiplied by the wheel torque estimated value Tw (step 285). Used for calculation of the motion model C4 (FIG. 2B). The reduced control gain FBx is used when the amplitude of the noise vibration can be roughly estimated in advance (when it can be measured at the time of vehicle assembly or setting, or when it can be estimated from the value of the vibration spectrum intensity I (φ)). Is)
FBx = FB × (f−fo) / f (13)
May be given by Here, FB is a control gain during normal operation, fo is the amplitude of noise vibration at the estimated wheel rotation speed value, and f is the amplitude of the current wheel rotation speed value. In addition, since the motion model of this embodiment is a linear model, the correction amount of the request drive torque corresponding to the wheel torque estimated value Tw is reduced by multiplying the wheel torque estimated value Tw by the reduced control gain FBx. . If the amplitude of the noise vibration cannot be estimated, the FB may be reduced to an arbitrary predetermined value.

  Further, in FIG. 8 described above, it is omitted because it is not expected in ordinary vehicles, but it is also omitted in the frequency bands [Ne1] and [Ne2] of the noise vibration depending on the rotational speed. It is determined whether or not it overlaps with the vibration suppression frequency range [Nt], and if it overlaps, the wheel torque estimated value Tw is used by using the reduced control gain without removing the frequency band [Ne]. May be input to the motion model C4.

  FIG. 9 shows that all the generated frequency bands [Ne1], [Ne2], and [Nw] of the noise vibration depending on the rotational speed and the vehicle speed are overlapped with the vibration suppression frequency range [Nt] of the pitch bounce vibration. The example of the process in the case of changing the signal processing method depending on whether or not to perform is shown in the form of a flowchart. Referring to FIG. 8, first, similarly to the example of FIG. 8, the wheel rotation speed value ω of the drive wheel is a removal frequency for removing the frequency-invariant noise vibration as illustrated in FIG. 7C. The filter is passed through a band cut filter having a band [Nc], and a frequency component corresponding to a frequency-invariant vibration such as a resonance frequency of the drive system mechanism is removed (step 310). Next, the calculation of the frequency Ne1 and Ne2 of the noise vibration depending on the drive output shaft rotational speed ne, the determination of the removal frequency band [Ne1] and [Ne2] corresponding to each of these, the frequency Nw of the noise vibration depending on the vehicle speed Vx Calculation and determination of the removal frequency band [Nw] corresponding to the calculation are performed (step 320).

Thereafter, the bands [Ne1], [Ne2], and [Nw] are selected in order, and it is determined whether or not each band overlaps with the vibration suppression frequency band [Nt] of the pitch / bounce vibration to be controlled ( Steps 340 and 345) If there is no overlap, the wheel rotational speed ω is passed through the variable band cut filter of the selected band as in the case of FIG. If the signal is removed (step 350) and overlapped, the control gain FB is reduced (step 360). Whether or not the removal frequency band and the vibration suppression frequency band overlap, as in the example of FIG. 8, about the highest value (Nxhi) and the lowest value (Nxlo) of each removal frequency band,
Nthi <Nxlo (20a ′) or Nxhi <Ntlo (20b ′)
(N1, Ne1, Ne2, and Nw are set in order in Nx. When there are a plurality of removal bands as shown in FIGS. 7A and 7B, respectively. (Equation (20a ′, b ′) is examined for the upper and lower limits of the band of.) In addition, the control gain is reduced when the noise vibration amplitude fox (the amplitudes of the noise vibrations of the bands [Ne1], [Ne2], and [Nw]) can be roughly estimated in advance.
FB ← FB-FB (fox / f)
Or by subtracting FB (fox / f) from the control gain FB. (Thus, when both [Ne1] or [Ne2] and [Nw] overlap [Nt], the final FB value is FB (1-fo _{NE1 or NE2} / f-fow / f). Note that the control gain FB may be reduced by subtracting or multiplying an arbitrary predetermined value.

  Then, after the removal of the noise frequency component or the reduction of the control gain is executed, a value obtained by multiplying the estimated wheel torque value calculated by the equation (5) using the processed wheel rotational speed value ω and the control gain FB Is input to the motion model C4 (steps 380 and 390).

  Note that only one or two of noise vibration depending on the vehicle speed, noise vibration depending on the rotational speed, and noise vibration of the resonance frequency of the drive system mechanism may be removed. Further, when the estimated wheel torque value is calculated using the engine rotational speed ne or the transmission rotational speed no, noise vibration may be removed by the same processing as in FIG. 8 or FIG.

Reduction of control gain of driving torque compensation component As already mentioned, in the vibration suppression control apparatus of the present invention, a compensation reducer C9 may be provided in addition to the configuration described above. In the noise reduction detection process, the compensation reducer C9 detects a variable frequency vibration that does not depend on the vehicle speed or the drive output shaft rotation speed, or the amount of use of the vehicle wheel or the drive device. When it increases, it functions to reduce the control gain of the compensation component of the drive torque transmitted from the vibration suppression controller to the drive controller.

In the operation of the compensation reducer C9, it is determined whether or not the following condition is satisfied.
(1) When information on the presence of frequency-variable vibration that does not depend on the vehicle speed or the drive output shaft rotational speed is received from the vibration detector C8. (2) When the travel distance after the start of use of the vehicle exceeds a predetermined value. (The travel distance may be obtained from an arbitrary travel control device mounted on the vehicle.)
(3) When the number of inversions of the wheel torque estimation value exceeds a predetermined value (the number of inversions of the wheel torque estimation value is received when the wheel torque estimation value is received from the wheel torque estimator, that is, the change increases. (It may be obtained by counting the time of decreasing or increasing to decreasing (such as when the differential value is reversed positive or negative).)
(4) When the inversion rotation of the compensation component exceeds a predetermined value (the number of inversions of the compensation component is at the time of inversion, that is, when the change changes from increase to decrease or from decrease to increase (inversion of the positive / negative differential value) It may be obtained by counting time etc.)
(5) When the ratio of the sum or average value of the compensation components in the predetermined period to the sum or average value of the estimated wheel torque exceeds a predetermined value

  The state in which the above condition (1) is satisfied is, as already mentioned, that the vibration detector C8 detects frequency-variable vibration that does not depend on the vehicle speed or the drive output shaft rotational speed. It is difficult to predict in which frequency band the frequency appears. Further, when the above conditions (2) to (4) are satisfied, the vehicle travels after the vehicle starts to be used longer, or the wheel torque estimated value or the number of inversions of the compensation component is increased. This is a state in which the aging of the component is progressing due to the use of the wheel or the drive device, and the occurrence of vibrations that are not observed during the manufacture and assembly of the vehicle is expected. When the condition of the above (5) is satisfied, the aging of the component due to the use of the vehicle wheel or the driving device proceeds, and the compensation component, that is, the target value of the wheel torque value, the estimated value of the wheel torque, That is, it is a state in which it is estimated that the difference between the wheel torque value and the target value is large.

  Thus, when any one of the above (1) to (5) is established, the state of the vehicle at that time can be determined to be a state where the planned vibration suppression control cannot be executed or is difficult to execute. . Therefore, when any of the above (1) to (5) is established, the compensation reducer C9 applies a coefficient less than 1 to the compensation component obtained by converting the output from the multiplication computing unit C5 into the driving torque. The multiplied value, that is, the reduced compensation component is transmitted to the adder C1a.

The compensation reducer C9 may determine only some of the above conditions (1) to (5). Each predetermined value of the conditions (2) to (5) may be arbitrarily set experimentally or theoretically in advance. Further, the amount of reduction in the control gain may be determined depending on the value of each variable referred to in the conditions (2) to (5). For example, as the value of each variable increases, the control gain May be set to be small. The conditions (1), may be set to control gain as the value is increased is reduced by receiving a kappa _total of the above formula (17a).

  Thus, according to the above-described embodiment, noise vibration is generated in the disturbance input of the wheel torque, and even when there is a possibility of occurrence or amplification of the longitudinal vibration of the vehicle or the possibility of the noise vibration, By reducing the compensation component, generation or amplification of the longitudinal vibration of the vehicle is suppressed.

  Although the above description has been made in relation to the embodiment of the present invention, many modifications and changes can be easily made by those skilled in the art, and the present invention is limited to the embodiment exemplified above. It will be apparent that the invention is not limited and applies to various devices without departing from the inventive concept.

  For example, although the wheel torque estimated value in the above embodiment is estimated from the wheel speed, the wheel torque estimated value may be estimated from parameters other than the wheel speed. Further, the vibration suppression control in the above embodiment is a vibration suppression control using the theory of an optimal regulator assuming a sprung or sprung / unsprung movement model as a movement model. As long as it uses wheel torque, it can also be applied to those that adopt a motion model other than those introduced here, or those that control vibration using a control method other than the optimal regulator. It belongs to the scope of the invention. Further, the presence / absence of noise vibration and its frequency band / characteristic may be detected by a method / algorithm other than those exemplified, and such a case should be understood to be within the scope of the present invention.

  Further, in the above description, some examples of noise vibration generated due to the structure of the wheel or the driving device are listed, but the generated frequency band is the vehicle speed or the driving device regardless of the excitation source. If it can be estimated based on the rotational speed of the output shaft, it is removed using the frequency component removing means. The concept of the present invention may be applied to the case where the frequency band of noise vibration is specified at the time of manufacture and assembly of the vehicle, and such a case should be understood to belong to the scope of the present invention. Furthermore, noise vibrations are eliminated by passing a signal such as a wheel speed value for calculating the estimated wheel torque through a band-pass filter that passes the frequency band of pitch bounce vibration aimed at damping by damping control. Even if it does, the same effect is acquired. Also in this case, the control gain may be reduced when the noise vibration band overlaps the frequency band of the pitch bounce vibration.

FIG. 1A shows a schematic diagram of an automobile in which a preferred embodiment of a vibration damping control device according to the present invention is realized. FIG. 1B is a more detailed schematic diagram of the internal configuration of the electronic control device of FIG. 1A. FIG. 2A is a diagram for explaining the state variables of the vehicle body vibration that are suppressed in the vibration damping control device that is one of the preferred embodiments of the present invention. FIG. 2B is a diagram showing the configuration of the vibration damping control in the preferred embodiment of the present invention in the form of a control block diagram. FIG. 3 is a diagram for explaining a mechanical motion model of vehicle body vibration assumed in the vibration damping control device according to the preferred embodiment of the present invention. FIG. 3A shows a case where a sprung vibration model is used, and FIG. 3B shows a case where a sprung / unsprung vibration model is used. FIG. 4 shows a data acquisition process of the noise vibration detection process in the vibration detector C8 in the form of a pro chart. In S50 to S58, an integer of 1 or more is sequentially given to kw (until the upper limit of Nwr exceeds φmax). In S60 to S68, an integer of 1 or more is sequentially given to ke1 (until the upper limit of Ne1r exceeds φmax). In S70 to S78, an integer of 2 or more is sequentially given to ke2 (until the lower limit of Ne2r falls below the minimum frequency of the vibration spectrum). FIG. 5 shows the data determination process of the noise vibration detection process in the vibration detector C8 in the form of a pro chart. In S120 to S148, w, e1, and e2 are sequentially set to x (the order is arbitrary). In S130 to S145, an integer of 1 or 2 or more is sequentially given to kx (similar to the case of kw, ke1, and ke2 in FIG. 4). FIG. 6A is a diagram schematically showing a process of acquiring a vibration spectrum (right) of a wheel torque index value (left) by FFT analysis. (B) is a graph showing the spectrum determination array κi in which the frequency band in which the intensity I (φ) exceeds the predetermined value Io is set to 1 and the others are set to 0 in the vibration spectrum of (A). The right diagram is a diagram representing the total value κ of the spectrum determination array κi acquired a plurality of times (five times in the illustrated example) as a graph. (C) is a diagram schematically illustrating the process of determining the lower limit value and the upper limit value of the frequency-invariant vibration band. Y is a data (frequency) point at which equation (14b) is established, and N is a data (frequency) point at which equation (14b) is not established. In the example shown in the figure, the equation (14b) is sequentially checked from the smaller frequency φ, and the point where the equation (14b) is satisfied is that log Δφ (Δφ is a frequency interval) is 0.2 or more. Then, when the first point is set as the lower limit value, and when the point where equation (14b) is not satisfied continues for more than 0.2 in log Δφ (Δφ is the frequency interval), the first point Set the previous point as the upper limit. As shown in the figure, there may be a case where there are two or more vibration bands whose frequency does not change in the array κ. FIG. 7 is a schematic diagram showing a removed frequency band profile of a band cut filter for removing noise vibration. (A) is the removal frequency band [Nw] of the band cut filter that removes the noise vibration dependent on the vehicle speed, and (B) is the removal frequency band [Ne1] of the band cut filter that removes the noise vibration dependent on the rotation speed. Or, [Ne2], and (C) is the removal frequency band [Nc] of the band cut filter that removes noise vibrations that generate or amplify the resonance of the drive train mechanism. In the illustrated example, there are two to three removal bands. However, an arbitrary number of removal bands may exist, and when no noise vibration is detected, there is no removal band. FIG. 8 shows, in the form of a flowchart, one embodiment of a calculation process for calculating a wheel torque estimated value Tw from which noise vibration components have been removed. FIG. 9 shows another embodiment of a calculation process for calculating the wheel torque estimated value Tw from which the noise vibration component has been removed, in the form of a flowchart. In step 330 to step 375, w, e1, and e2 are sequentially set to x (the order is arbitrary).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Car body 12FL, FR, RL, RR ... Wheel 14 ... Accelerator pedal 20 ... Drive device 30FL, FR, RL, RR ... Wheel speed sensor 32 ... G sensor 50 ... Electronic control unit

Claims (7)

A vehicle vibration control device that suppresses pitch or bounce vibration of the vehicle by controlling a drive output of the vehicle, the wheel torque acting on a wheel generated at a contact point between the wheel of the vehicle and a road surface Or a driving torque compensator that compensates the driving torque of the vehicle so as to suppress the pitch or bounce vibration amplitude based on the estimated value, and when input to the driving torque compensator, The wheel torque or its estimated value includes a noise frequency component in a frequency band which is a function of the vehicle speed of the vehicle that generates a driving torque that generates or amplifies vibrations or a function of the rotational speed of the output shaft of the driving device of the vehicle. and determining the noise frequency component determining means for determining dolphin not, when the wheel torque or said noise frequency component to the estimated value thereof is determined to be included Characterized in that the noise frequency component reducing means for reducing the vibration component in the frequency band of the noise frequency component is determined to be included the in the drive torque to be compensated is provided by serial driving torque compensator Equipment.   2. The apparatus according to claim 1, wherein the noise frequency component reducing means reduces the vibration component in the frequency band of the noise frequency component in the wheel torque value or an estimated value thereof, thereby making the driving torque compensation component. A vibration component in a frequency band of the noise frequency component in the apparatus is reduced. 3. The apparatus according to claim 1, wherein the noise frequency component determination unit includes whether or not the wheel torque or an estimated value thereof includes a noise frequency component whose frequency is invariant regardless of a running state of the vehicle. And when it is determined that the noise frequency component vibration component whose frequency band is invariant is included, the noise frequency component reducing means is in the traveling state of the vehicle in the compensation component of the driving torque. A device that reduces vibration components in a frequency band of the noise frequency component whose frequency is not changed regardless of the frequency band. 3. The apparatus according to claim 1, wherein the noise frequency component determination unit determines that the wheel torque or an estimated value thereof includes a noise frequency component whose frequency band cannot be specified, or the noise frequency component determination. When the frequency band of the noise frequency component specified by the means overlaps the frequency of the pitch or bounce vibration to be suppressed by the vibration suppression control device, the noise frequency component reduction means controls the compensation component of the driving torque. An apparatus characterized by reducing gain. 5. The apparatus according to claim 1 , wherein the noise frequency component determination unit includes the wheel speed, a differential value of the wheel speed, a rotational speed of an output shaft of the driving device, a differential value of the rotational speed, The wheel torque estimated value estimated based on the wheel speed or the rotational speed of the output shaft of the vehicle drive device, the vehicle longitudinal acceleration, and the drive torque applied from the drive torque compensation unit to the vehicle drive device An apparatus comprising: means for detecting whether or not the noise frequency component is included in a wheel torque index value selected from the group consisting of:   6. The apparatus according to claim 5, wherein the noise frequency component determination means determines whether or not the noise frequency component is included in the wheel torque index value by frequency analysis of the wheel torque index value. Equipment. A vehicle vibration control device that suppresses pitch or bounce vibration of the vehicle by controlling a drive output of the vehicle, the wheel torque acting on a wheel generated at a contact point between the wheel of the vehicle and a road surface Or a driving torque compensator that compensates the driving torque of the vehicle so as to suppress the pitch or bounce vibration amplitude based on the estimated value, and when input to the driving torque compensator, Noise frequency component determining means for determining whether or not a noise frequency component that generates a driving torque for generating or amplifying vibration is included in the wheel torque or an estimated value thereof; and the noise frequency component in the wheel torque or an estimated value thereof The contribution of the noise frequency component in the driving torque compensated by the driving torque compensator when it is determined that Is provided and the noise frequency component reducing means for reducing,
The noise frequency component determination means is the travel distance of the vehicle, the number of inversions of the wheel torque value or its estimated value, the number of inversions of the compensation component of the drive torque given from the drive torque compensation unit to the vehicle drive device, And the amount of use of the vehicle wheel or the drive device, which is an amount selected from the group consisting of the ratio of the driving torque compensation component and the wheel torque value or its estimated value in a predetermined period, is a predetermined value. When exceeding, it is estimated that the noise frequency number component is included in the wheel torque or its estimated value .

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