JP4910794B2 - Drive control device for controlling vibration control of vehicle - Google Patents

Description

  The present invention relates to a drive control device for a vehicle such as an automobile, and more specifically, a drive control device having a vibration suppression control function for controlling vehicle output (drive force or drive torque) to suppress vibration of a vehicle body. Concerning.

  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. At the time of driving, this is reflected in “wheel torque” (torque acting between the wheel and the grounded road surface) acting on the 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 such vibration suppression control by drive output control, there is a request for acceleration / deceleration of the vehicle using a motion model constructed assuming a dynamic model of so-called unsprung and unsprung vibrations of the vehicle body. Or, when an external force (disturbance) acts on the vehicle body 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 controlled so that the predicted vibration is suppressed. Adjusted.

In the vibration suppression control by the drive output control as described above, the vibration source is adjusted by adjusting the source of the force that generates the vibration rather than suppressing the vibration by absorbing the vibration energy generated as in the vibration suppression control by the suspension. Since the generation of vibration energy is suppressed, 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.
JP 2004-168148 A JP 2006-69472 A

  When the vehicle drive device is a gasoline engine, the drive output of the engine is controlled by the intake air amount (and ignition timing, etc.) as is well known. Therefore, when the drive output control for vibration suppression control as described above is executed, the intake air amount is determined based on the driving force according to the driver's accelerator pedal depression amount or the like (or the automatic travel control device or the like) The required drive torque compensation component that vibrates up and down to suppress the pitch bounce vibration is controlled so as to fluctuate according to the control amount superimposed on the required amount of drive torque (required drive force or torque). It becomes. The amplitude of the required drive torque compensation component is determined by the magnitude of the frequency component that causes the acceleration / deceleration request of the vehicle or the pitch bounce vibration of the wheel torque disturbance acting on the wheel. When the frequency component causing the bounce vibration is relatively large, and the control amount of the intake air amount on which the required drive torque compensation component is superimposed exceeds the variable range of the intake air amount, it is required by the vibration suppression control. The fluctuation of the intake air amount is not realized, and the vibration control effect is reduced.

  In this regard, in particular, in gasoline engines, idling speed control (ISC: Idle Speed Control) is performed separately from drive output control to maintain engine rotation stability at low loads. Intake air amount (ISC flow rate) is sent to the engine, and the variable range of the intake air amount allowed for drive output control is limited on the low load side due to the presence of the ISC flow rate. . Therefore, if the required drive torque compensation component of the vibration suppression control swings downward when the engine is in a low load state, fluctuations in the intake air amount are likely to be limited by the action of the ISC. It can happen that it decreases. However, the conventional technology does not consider that the fluctuation of the intake air amount for the vibration suppression control can be limited as described above.

  According to the present invention, there is provided a drive control device of a type that executes drive output control for vibration suppression control of a vehicle that uses a gasoline engine as a drive device, and the amount of intake air is reduced during execution of vibration suppression control. Provided is a vehicle drive control device improved so that a vibration damping effect can be obtained better without fluctuation being limited by ISC.

  A drive control device for a gasoline engine of a vehicle that controls vibration output of the vehicle and suppresses vehicle pitch or bounce vibration according to the present invention is generated at a contact point between a vehicle wheel and a road surface. A vibration suppression control unit that controls the engine drive torque to suppress the pitch or bounce vibration amplitude based on the wheel torque acting on the wheel, and an idle rotation speed control intake air amount (ISC) for controlling the engine idle rotation speed An idle rotation speed control unit (ISC unit) that controls the flow rate), and the idle rotation speed control unit reduces the idle rotation speed control intake air amount when executing the vibration suppression control by the vibration suppression control unit. To do.

  As described above, in an ordinary gasoline engine, the ISC flow rate is supplied to the engine in order to stabilize the rotation state (driving state) at the time of low load, and the intake air amount for drive output control is variable. The range is limited on the low load side. Accordingly, when the drive torque required by the vibration suppression control swings downward, particularly when the engine is under a low load (for example, when going downhill), the intake air amount corresponding to the drive torque required by the vibration suppression control Is lower than the ISC flow rate, the fluctuation of the intake air amount is not achieved (the intake air amount is not lower than the ISC flow rate), and the expected vibration control effect cannot be obtained. Therefore, in the above-described configuration of the present invention, the ISC flow rate is reduced when the vibration suppression control is executed by the vibration suppression control unit, so that the intake air amount is required to be driven by the vibration suppression control. The control configuration is modified so that it can be reduced following the torque. In other words, by reducing the ISC flow rate, the variable range of the intake air amount is expanded, and at least the possibility that the amplitude of the drive torque by the vibration suppression control is limited on the lower side is reduced.

  With regard to the timing of the ISC flow reduction when executing the above vibration suppression control, the ISC is necessary to ensure engine stability and should not be reduced unnecessarily. As an aspect, the ISC flow rate may be reduced (as compared to before the start of the vibration suppression control) when the vibration suppression control by the vibration suppression control unit is started. The vibration suppression control is executed when a vehicle acceleration / deceleration request is made or when a disturbance occurs in the wheel torque, so that the vehicle is naturally running. That is, since it is not normally possible to execute the vibration suppression control when the vehicle is stopped, the ISC flow rate is reduced when the vibration suppression control is started, and when the vehicle is stopped, the ISC flow rate is reduced in a normal manner. It may be supplied. However, ISC has the purpose of maintaining the stability of the engine operating state not only when the vehicle is stopped but also when the engine is under low load. When necessary, that is, when the ISC flow rate is supplied to the engine under the control of the ISC unit, the ISC flow rate is reduced when the intake air amount required by the vibration suppression control unit cannot be changed downward. It may be. The detection of the state in which the intake air amount required by the vibration suppression control unit cannot be changed downward is, for example, whether the intake air amount detected while the vehicle is running substantially matches the ISC flow rate, or the throttle opening May be performed by detecting that a state substantially corresponding to the opening degree at which the ISC flow rate is achieved continues for a predetermined period.

  In the above-described apparatus of the present invention, as a specific aspect of the reduction of the ISC flow rate when the vibration suppression control is executed, for example, the ISC flow rate is determined in advance so as to achieve a predetermined engine speed when the vehicle is stopped. When the sum is the sum of the first component and the second component determined based on the engine speed, the second component may be substantially reduced to zero. According to such a configuration, even if the fluctuation of the driving torque required by the vibration damping control is large and the fluctuation amount greatly fluctuates downward, it is predetermined to achieve a predetermined engine speed when the vehicle is stopped. The first component is always ensured, thus avoiding that the operating state of the engine becomes extremely unstable (a situation where the amount of intake air is less than when the vehicle is stopped is avoided). ).

  When the ISC flow rate is reduced as described above, the total amount of intake air supplied to the engine is also reduced. Therefore, when the vehicle is driven at a certain speed or acceleration, the vehicle driver (or an automatic travel control device or the like), for example, deepens the accelerator pedal in a state where the ISC flow rate is reduced than in a state where the ISC flow rate is not reduced. It is necessary to give a larger required amount to the vehicle by stepping on the vehicle, which increases the operation burden. In view of this, the above-described apparatus of the present invention may include a configuration for reducing the operation burden of issuing a larger required amount (especially for the driver). As such a configuration, for example, the drive control device includes a required drive torque determination unit that determines a required drive torque of the engine, and an intake air amount determination unit that determines a target intake air amount based on the required drive torque, The damping control unit corrects the required driving torque with a required driving torque compensation component calculated to suppress the pitch or bounce vibration amplitude, and the intake air amount determining unit corrects the target intake air based on the corrected required driving torque. When the amount is determined, the target intake air amount that is determined based on the corrected required drive torque when the ISC air amount is reduced when the vibration suppression control is executed by the vibration suppression control unit May be increased. According to such a configuration, the operation burden of increasing the requested drive amount to increase the intake air amount when the ISC flow rate is reduced is reduced.

  According to the drive control device of the present invention described above, if necessary, when the pitch bounce vibration suppression control by the drive output control is executed in the gasoline engine, the ISC flow rate is reduced, and accordingly, the drive output control is performed. By expanding the variable range on the low load side of the intake air amount, a state in which the intake air amount can satisfactorily follow the request from the vibration suppression control is provided. With this control configuration, it becomes easy to realize fluctuations in drive output as expected in vibration damping control, that is, fluctuations in wheel torque, and the vibration damping effect is improved.

  It should be particularly understood that, in the pitch bounce vibration suppression control that is the subject of the present invention, the pitch is independently independent of the engine load requirement required by the driver or the automatic travel control device. A slightly unique drive control may be executed in order to request a vertical vibration of the drive torque for the purpose of canceling the bounce vibration. In the case of engine drive control for the purpose of accelerating / decelerating the rotation of a typical vehicle or wheel, generally, a change in drive torque required for the engine is a request from a driver or an automatic travel control device or the like. Therefore, it is considered that there is not much that fluctuates greatly from the engine load demand by the driver or the automatic travel control device. Therefore, if the engine is in a low load condition, the engine load requirement will not fluctuate so much. However, in the case of drive output control in pitch / bounce vibration control, even if the engine load requirement required by the driver or the automatic travel control device is low, pitch / bounce vibration is caused among disturbances to wheel torque. If the component to be used is large, the amplitude of the drive torque required for the engine may fluctuate greatly. In this case, the required intake air amount may be lower than the ISC flow rate. The control configuration of the present invention pays attention to the situation that occurs in such a unique control method of the pitch / bounce vibration suppression control, and when the pitch / bounce vibration suppression control is incorporated in the drive control of the gasoline engine,・ It can be said that pitch bounce vibration suppression control is appropriately reflected in the vehicle and the vibration suppression effect is effectively exhibited while coordinating the bounce vibration suppression control with the existing ISC. .

  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 Apparatus FIG. 1A schematically shows a vehicle such as an automobile on which a preferred embodiment of a drive control apparatus that executes vibration suppression control of the present invention is mounted. 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. The engine 22 is a gasoline engine in a known manner, and the throttle valve 22a has a throttle valve 22a for adjusting the intake air amount so as to achieve the required drive torque determined according to the depression amount of the accelerator pedal and the control amount described below. The opening is controlled. Although not shown for simplicity, the vehicle 10 is provided with a braking 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. . The vehicle may be a four-wheel drive vehicle or a front wheel drive vehicle.

  The drive output of the engine 22, that is, the throttle opening is adjusted by operating a throttle valve actuator (not shown) based on a command (target throttle opening θst) of the electronic control unit 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 device 50 includes a signal representing a wheel speed Vwi (i = FL, FR, RL, RR) from a wheel speed sensor 30i (i = FL, FR, RL, RR) mounted on each wheel, a vehicle Signals such as the engine rotational speed ne, the transmission rotational speed no, and the accelerator pedal depression amount θa are input from sensors provided in the respective sections. 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 device 50 includes a drive control device 50a for controlling the operation of the engine and other drive devices 20, and a braking device (not shown). ) Of the brake control device 50b for controlling the operation of As shown in the drawing, the braking control device 50b receives electric signals in a pulse format that are sequentially generated every time the wheels rotate by a predetermined amount from the wheel speed sensors 30FR, FL, RR, RL of each wheel, The rotational speed of the wheel is calculated by measuring the time interval at which such sequentially input pulse signals arrive, and the wheel speed value r · ω is calculated by multiplying this by the wheel radius. Then, the wheel speed value r · ω is transmitted to the drive control device 50a and used for calculation of the estimated wheel torque 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 drive request from the driver is determined based on the accelerator pedal depression amount θa, the required drive torque determining unit 51 for determining the required drive torque of the engine requested by the driver, and the vehicle body by the drive torque control. And a vibration suppression control unit 52 that calculates a required drive torque compensation component for executing the pitch / bounce vibration vibration suppression control of and corrects the required drive torque. In the pitch / bounce vibration damping control, as will be described in more detail later, (1) calculation of the estimated wheel torque of the driving wheel by the force acting between the driving wheel and the road surface; 2) Calculation of the pitch / bounce vibration state quantity based on the motion model of vehicle body vibration, (3) Calculation of the correction amount of the wheel torque for suppressing the pitch / bounce vibration state quantity, and correction of the required drive torque based on this. Based on the command value of the required drive torque corrected by the vibration suppression control unit 52, the intake air amount determination unit 53 determines a target value of the intake air amount that achieves the required drive torque (intake air amount). In addition, target values of parameters for realizing the requested engine operation, such as ignition timing and fuel injection amount, are also determined as appropriate.

  Further, the drive control device 50a is provided with an idle rotation speed control (ISC) unit 54 for maintaining stable rotation of the engine against engine friction and other rotational loads. As will be described in detail later, the ISC unit is a stable engine when the vehicle is stopped or in a low-load operation state (when the engine speed is relatively high with respect to the load, for example, when going downhill). The amount of air sent to the engine (ISC flow rate) is determined with reference to the engine speed. Then, in the target throttle opening determining unit 55, a throttle opening corresponding to the intake air amount based on the required driving torque corrected by the required driving torque compensation component by the vibration suppression control, and a throttle opening corresponding to the ISC flow rate Are determined, and the final target value θst of the throttle opening is determined and transmitted to the throttle valve actuator of the engine 22 as a control command. Further, since the intake air amount for achieving the required drive torque varies depending on the magnitude of the ISC flow rate, the set value of the ISC flow rate is transmitted to the intake air amount determining unit 53, and the intake air amount corresponding to the required drive torque is set. Configured to be considered in decisions.

  It should be understood that each part of the drive control device of the present invention described above is realized by a processing operation of a microcomputer or the like in the electronic control device 50. Hereinafter, the operation of the vibration suppression control by the drive torque control and the operation of the ISC executed in cooperation therewith will be described in detail.

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 pitch / bounce vibration damping control exemplified here, a motion model of the pitch / bounce vibration of the vehicle body is constructed, and the required drive torque (value converted to wheel torque) in the model, A state obtained from the model by calculating the displacement z and θ of the vehicle body and the rate of change dz / dt and dθ / dt, that is, the state variable of the vehicle body vibration when the current wheel torque (estimated value) is input. The drive torque of the drive device (engine) is adjusted so that the variable converges to 0, that is, 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. The operation of each control block is executed by either the drive control device 50a or the braking control device 50b of the electronic control device 50 (except for C0 and C3). Referring to FIG. 2B, in the drive torque control according to the embodiment of the present invention, a required drive torque determination unit 51 that gives a driver's drive request to the vehicle, and suppresses pitch / bounce vibration of the vehicle body. It is comprised from the vibration suppression control part 52 for correcting the driver | operator's drive request (refer FIG.1 (B)). In the required drive torque determination unit, 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), and then the required drive torque is calculated. Then, the control command to the throttle valve actuator is determined in the order of the target intake air amount and the target throttle opening degree (C2: target values of other operating parameters such as ignition timing and fuel injection amount are also determined). It is transmitted to the driving device (C3). Although not shown in FIG. 2B, a component for realizing the ISC flow rate is further added to the target throttle opening.

  On the other hand, the vibration suppression control unit includes a feedforward control 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 motion model portion (C4) of the bounce vibration is input, and in the motion model portion (C4), the response of the state variable of the vehicle body to the input torque is calculated, and the required driving wheel torque that converges the state variable to the minimum is calculated. A correction amount 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 correction amount of the required wheel torque with respect to the disturbance is also calculated. The correction amount of the required wheel torque of C5 is converted into the required torque unit of the drive device (required drive torque compensation component) and transmitted to the adder (C1a). Thus, the required drive torque is obtained by the pitch bounce vibration. After being corrected so as not to occur, it is converted into a control command (C2) and given to the driving device (C3).

The wheel torque input as a disturbance to the feedforward control part may ideally be detected by actually providing a torque sensor for each wheel, but a torque sensor should be provided for each wheel of a normal vehicle. Therefore, the wheel torque estimated value estimated by the wheel torque estimator (C6) from other detectable values in the running vehicle is used as the disturbance input of the wheel torque. 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). ]

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. The

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 to be larger than the norm, components having a larger norm are 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.

  As shown in the block diagram of FIG. 2B, the actual operation of the vibration suppression control unit is performed by solving the differential equation of the equation (2a) using the torque input value in the motion model C4. A 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). (State 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 the natural vibration of the system. Only frequency components in a band having a certain spectral characteristic centered on the number are obtained. Thus, by constructing the converted value of U (t), that is, the required driving torque compensation component, from the required driving torque, in the required driving torque, the natural frequency component of the system, ie, the vehicle body. The component causing the pitch bounce vibration 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).

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が０を収束させるゲイン行列Ｋを決定することができる。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, a gain matrix K that converges the magnitude of the state variable vector to 0 can be determined. it can. Actual vibration suppression control is the same as in the case of FIG.

When the vehicle drive device is a gasoline engine with respect to the idle rotation speed control , as described above, the ISC flow rate corresponds to the above required drive torque under the control of the ISC unit in order to stabilize the rotation state of the engine. In addition to the target intake air amount, it is supplied to the engine. In such an ISC, when the engine is in an idling state (while the vehicle is stopped), the throttle opening is set so that an air amount for stably maintaining the engine is sucked into the engine. . Even when the vehicle is running, if the amount of intake air is too low when the engine speed is high relative to the engine load, engine combustion may become unstable, catalyst deterioration, engine surge, etc. Since problems such as poor maneuverability occur, the throttle opening is increased so that the ISC flow rate increases as the engine speed increases. Therefore, in a normal gasoline engine while the vehicle is running, the intake air amount (first component) that stabilizes the engine rotation in the idling state, as illustrated in FIG. A flow rate increased by a flow rate increment (second component) determined as a function of the rotational speed is always supplied as the final ISC flow rate. The actual opening at the throttle valve is the final ISC opening with a fixed throttle opening (see FIG. 4 (B)) that is determined to achieve the final ISC flow rate. The throttle opening corresponding to the intake air amount based on the required drive torque is controlled to be a value added.

Correction of ISC for Vibration Suppression Control As can be understood from the above description, when the required drive torque compensation component by the vibration suppression control superimposed on the required drive torque is due to disturbance input, Independent of the drive request from the user (the vibration control system is normally a linear system as in the illustrated example), it vibrates up and down. Therefore, if the fluctuation width of the disturbance is large, the driving request from the driver is relatively small, that is, the required driving torque after correction (after passing through the adder C1a) is large up and down even when the engine is in a low load state. It may swing. However, the conventional gasoline engine drive control is configured such that the final ISC flow rate or the corresponding final ISC opening is always maintained, so that the drive torque required by the vibration suppression control is realized. Inability to occur may occur.

  For example, consider a case where the engine is in a low load state, that is, the throttle opening corresponding to the driving torque requested by the driver is small, and therefore the actual opening of the throttle valve is relatively close to the final ISC opening. If the amplitude of the required drive torque compensation component by vibration suppression control is small, the throttle opening component corresponding to the required drive torque compensation component is not limited as shown in FIG. This is reflected in the actual opening of the valve, so that the expected damping effect is obtained. However, the amplitude of the required drive torque compensation component by vibration suppression control is large, and therefore, as shown in FIG. 5B, the throttle opening command value component corresponding to the fluctuation of the required drive torque compensation component is reduced. The throttle opening is not allowed to be smaller than the final ISC opening when the required drive torque after correction is negative (the state indicated by the dotted line in the figure). Therefore, the intake air amount based on the required driving torque and the throttle opening corresponding to this are prohibited from becoming negative values. Therefore, the intake air amount is not reduced according to the demand for vibration suppression control. The amount is not reduced, and the fluctuation of the driving torque required by the vibration suppression control is not realized. In addition, as described above, the second component of the final ISC opening increases depending on the engine speed, so that the range where the required drive torque is not reflected increases as the engine speed or the vehicle speed increases. Thus, a state in which the request for damping control is not realized is likely to occur, and the damping effect is reduced (see the dashed line in FIG. 5).

  Therefore, in the ISC section of the drive control device of the present invention, as described in the “Disclosure of the Invention” section, the throttle opening is set in accordance with the amplitude of the required drive torque compensation component during the execution of the vibration suppression control. The ISC flow is reduced so that it can be varied to smaller values.

FIG. 6A is a flowchart showing a final ISC flow rate and final ISC opening setting process repeatedly executed at a predetermined cycle time during operation of the vehicle in the ISC unit in the drive control apparatus of the present invention. It is expressed in the form. Referring to the figure, in the setting process in the ISC section, first, as in the conventional ISC, the ISC flow rate for maintaining the idle state rotation when the vehicle is stopped, that is, the first ISC flow rate is set. Next, it is determined whether or not the vibration suppression control is being executed, that is, whether or not the vibration of the required drive torque for suppressing the pitch bounce vibration is generated (step 10). Step 20). In this determination, for example, referring to the required drive torque compensation component U (output of C5) and its time differential value in the vibration suppression control unit, when their absolute values are both smaller than a predetermined minute amount. In other words, when it is substantially 0, it may be determined that the vibration suppression control is not operating. When vibration suppression control is not being executed, the second component of the ISC flow rate is based on the engine speed using the map illustrated in FIG.
(Step 30) is determined. Then, the final ISC flow rate is determined by adding the first and second components (step 40).

  On the other hand, if it is determined in step 10 that the vibration suppression control is being executed, the throttle opening that changes based on the request for vibration suppression control is set to ISC as illustrated in FIG. It is determined whether or not a situation that cannot be changed downward has occurred by reaching the opening degree (step 50). For example, the determination may be performed in one state where the actual opening at the throttle valve substantially matches the final ISC opening corresponding to the final ISC flow (when vibration suppression control is being performed). May be made by detecting that is persisting for a predetermined period of time. In this case, as illustrated in FIG. 6B, the difference between the target throttle opening value θst transmitted to the throttle valve actuator and the ISC opening θisc corresponding to the final ISC flow rate is a predetermined value (θo). When the following is true (step 51), the counter is started (step 52), and when the counter reaches a predetermined value while repeating the cycle (step 53), the actual opening at the throttle valve is opened. It may be determined that the angle θisc has been reached and the situation cannot be changed further downward. Note that the determination that the throttle opening is limited to the ISC opening is that the intake air amount corresponding to the required drive torque corrected by the vibration suppression control is substantially zero for a predetermined period. It may be determined by.

  Thus, when it is determined that the throttle opening reaches the ISC opening and the intake air amount cannot be further reduced, the first component of the ISC flow is set as the final ISC flow, and the second of the ISC flow is set. Are excluded from the final ISC flow (step 60). As a result, the final ISC flow rate is reduced, and the variable range of the intake air amount corresponding to the required drive torque is expanded downward by the amount by which the second component of the ISC flow rate is excluded. It should be understood that the first component of the ISC flow rate is maintained even when the reduction of the ISC flow rate is executed with respect to the process for reducing the ISC flow rate. According to this configuration, the intake air amount required to maintain the idle rotation speed while the vehicle is stopped is secured to a minimum, and the engine is caused by an excessive change in the intake air amount due to vibration suppression control. It is avoided that the operating state of the vehicle becomes extremely unstable.

  Thus, when the final ISC flow rate is determined (steps 40 and 60), the value is transmitted to the target throttle opening determining unit 55 (step 70), and is added to the intake air amount corresponding to the required drive torque, and the target throttle. The opening degree θst is determined.

  In the above processing, once the final ISC flow rate is reduced, the final ISC flow rate may be maintained in a reduced state until the vibration suppression control ends. In order to achieve such processing operation, when it is determined in step 50 that the throttle opening has not reached the ISC opening, it is determined whether or not the ISC flow rate reduction processing has already been performed (step 65). If the ISC flow rate reduction processing has already been performed, the first component of the ISC flow rate is set as the final ISC flow rate as it is in step 60. Then, the reduction of the ISC flow rate is canceled when it is determined in step 10 that the vibration suppression control is not executed. In the above configuration, the ISC flow rate is reduced when the actual throttle opening is less than the final ISC opening as required by the vibration suppression control. The ISC flow rate reduction process may be executed at the time when the control is started, that is, when it is determined in step 20 that the vibration suppression control is being executed. In that case, step 50 and step 65 are omitted.

  FIG. 7 schematically shows how the variable range of the intake air amount changes depending on the setting of the ISC flow rate at a certain vehicle speed. The left side of FIG. The state, that is, the state in which the ISC flow rate is not reduced as described above, and the right side is the state in which the ISC flow rate is reduced. Referring to the figure, when the vehicle speed is the same, the amount of air to be drawn into the engine (when the fluctuation component of the intake amount due to vibration suppression control is not taken into account) regardless of the magnitude of the ISC flow rate is Accordingly, the actual total intake air amount becomes the same value regardless of the presence or absence of the ISC flow rate reduction process. Further, as described above, the final ISC flow rate (at the time of the final ISC opening) is fixed regardless of the throttle opening corresponding to the required drive torque, and therefore, the intake air that changes corresponding to the required drive torque. The variable range of the amount is a range from when the throttle opening is the final ISC opening to when the throttle valve is fully opened. Therefore, if the required drive torque is relatively small (not considering the fluctuation component of the intake air amount due to vibration suppression control) in the normal state (left side in the figure), the actual total intake air amount is the final When a component close to the ISC flow rate and the fluctuation component of the intake air amount due to the vibration suppression control are superimposed on this and the component swings downward, the final ISC flow rate is reached immediately, and the change in the intake air amount is limited. It becomes.

  On the other hand, as shown on the right side in the figure, when the second component is removed from the final ISC flow rate or substantially zero, and the final ISC opening is set corresponding to this, the actual total intake air The amount will be farther from the final ISC flow than in normal conditions. Therefore, in this case, even if the fluctuation component of the intake air amount due to the vibration suppression control is superimposed, the possibility that the total intake air amount reaches the final ISC flow rate is low, and therefore the request for the vibration suppression control is easily reflected. As a result, the vibration control effect can be exhibited better.

  By the way, referring to FIG. 7, when the final ISC flow rate is reduced, the actual intake air amount is expanded in its variable range, but its absolute value does not change. In other words, the final ISC flow rate reduction processing is equivalent to reducing the zero point or starting point of the driver's drive request operation. Therefore, when the final ISC flow rate is reduced, in order to achieve the same vehicle speed, the driver needs to perform a larger drive request operation, which increases the operation burden on the driver. Therefore, in order to reduce such an operation burden, when the final ISC flow rate is reduced as described above, as shown in FIG. 8, the driver's requested drive operation amount (accelerator pedal depression amount). The configuration of the control may be modified so that the response amount of the throttle opening to is increased.

  The increase in the response amount of the throttle opening with respect to the driver's requested drive operation amount is an arbitrary stage of the process until the driver's requested drive operation amount is reflected in the throttle opening, for example, the requested drive operation amount from the requested drive operation amount It may be performed in the step of converting to torque or the step of converting the required driving torque into a target value of the intake air amount. However, the correction of the control configuration is performed so that the required drive torque compensation component by the vibration suppression control is reflected in the throttle opening without being amplified regardless of whether or not the final ISC flow rate is reduced. The

  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.

  The above embodiment is configured to supply the ISC flow rate by adjusting the throttle valve. However, a flow path for bypassing the throttle valve is provided in the intake pipe, and the flow rate of the bypass flow path is controlled by the ISC valve. It may be like this.

  Moreover, 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.

FIG. 1A shows a schematic diagram of an automobile in which a preferred embodiment of a drive control apparatus 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 illustrating a state variable of vehicle body vibration that is suppressed in the operation of the vibration suppression control unit of the drive 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 unit of 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. 4A is a map for determining the component (second component) of the ISC flow rate that increases according to the engine speed. FIG. 4B is a map for determining the throttle opening (final ISC opening) that achieves the final ISC flow rate. FIG. 5 shows the change over time of the actual opening of the throttle valve when the vibration suppression control is executed. (A) is an example when the fluctuation | variation of the request | requirement drive torque compensation component by vibration suppression control is comparatively small, (B) is a case where the fluctuation | variation of a request | requirement drive torque compensation component is comparatively large. In the figure, the “driver drive request equivalent opening” is the throttle opening that achieves the intake air amount (when vibration suppression control is not executed) corresponding to the required drive torque corresponding to the driver's drive request. Since the opening of the throttle valve is prohibited to be smaller than the ISC opening, the fluctuation of the required driving torque compensation component is relatively large, and even if the required driving torque requires an opening lower than the ISC opening, The opening degree of the throttle valve does not become equal to or less than the ISC opening degree, and the fluctuation (represented by the dotted line) of the required driving torque compensation component corresponding to the amount below the ISC opening degree is ignored. In (B), the alternate long and short dash line indicates that when the engine speed increases, the ISC opening increases, and the fluctuation range of the opening required corresponding to the required driving torque is further limited. Yes. FIG. 6A shows the ISC flow rate setting process in the ISC section of the present invention in the form of a flowchart. FIG. 6B is a flowchart showing a process for determining whether or not a situation has occurred in which the throttle opening in step 50 of FIG. 6A reaches the ISC opening and cannot be changed further downward. It is represented by. FIG. 7 is a diagram illustrating how the variable range of the intake air amount is changed by setting the ISC flow rate of the ISC unit in FIG. 6. FIG. 8 is a diagram showing the relationship between the accelerator pedal depression amount and the throttle opening. When the ISC flow reduction process of the ISC unit in FIG. 6 is performed (with ISC flow reduction), the normal state ( In this example, the throttle opening is increased with respect to the amount of depression of a certain accelerator pedal, rather than ISC flow reduction. The amount of increase in the throttle opening relative to the amount of depression of the accelerator pedal may be arbitrarily determined experimentally or theoretically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle body 12FL, FR, RL, RR ... Wheel 14 ... Accelerator pedal 20 ... Drive device 22 ... Gasoline engine 22a ... Throttle valve 30FL, FR, RL, RR ... Wheel speed sensor 50 ... Electronic control device 50a ... Drive control device 50b ... Brake control device

Claims (5)

A drive control device for a gasoline engine of a vehicle that controls a vehicle drive output to suppress a pitch or bounce vibration of the vehicle, and is generated at a ground contact point between the vehicle wheel and a road surface A vibration control unit for controlling the driving torque of the engine so as to suppress the pitch or bounce vibration amplitude based on the wheel torque acting on the wheel , and a predetermined engine speed when the vehicle is stopped in advance. An idle rotation speed control intake air amount that is the sum of the determined first component and a second component determined based on the engine speed is determined, and the intake air amount supplied to the engine is and a idle speed control section so as not to be lower than the rotational speed control intake air amount, the idle when the damping control execution by the damping control unit Damping control system for a vehicle rolling speed control unit is characterized by reducing the idle speed control intake air quantity.   The apparatus according to claim 1, wherein when the vibration suppression control by the vibration suppression control unit is started, the idle rotation speed control intake air amount is reduced compared to before the vibration suppression control is started. Features device. 2. The apparatus according to claim 1 , wherein when the intake air amount is determined to coincide with the idle rotation speed control intake air amount during execution of vibration suppression control by the vibration suppression control unit, the idle rotation speed is determined. A device characterized in that the amount of controlled intake air is reduced. The apparatus according to claim 1, wherein the idle rotational speed control intake air amount is reduced by the idle rotational speed control unit when the idle rotational speed control unit executes the vibration suppression control by the vibration suppression control unit. Wherein the second component is reduced to zero . The apparatus according to claim 1, comprising: a required drive torque determining unit that determines a required drive torque of the engine; and an intake air amount determining unit that determines a target intake air amount based on the required drive torque. A vibration control unit corrects the required drive torque by a required drive torque compensation component calculated to suppress the pitch or bounce vibration amplitude, and the intake air amount determination unit corrects the target intake based on the corrected required drive torque. The target intake air that is determined based on the corrected required drive torque when the idle rotation speed control intake air amount is reduced when the air amount is determined and the vibration suppression control is executed by the vibration suppression control unit. A device characterized by increasing the amount.

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