JP5115333B2 - Slip suppression control device - Google Patents

Description

  The present invention relates to a slip suppression control device for recovering a slip generated on a drive wheel of a vehicle to a grip state.

  When a drive wheel of a vehicle such as a passenger car or a truck slips, the behavior of the vehicle changes, or the propulsion efficiency decreases because the power generated by the power generation source cannot be effectively converted into the drive power. For this reason, when slip occurs in the drive wheel, it is necessary to quickly recover the grip of the drive wheel. Patent Document 1 discloses an automobile slip control device that adjusts the opening degree of a throttle valve so that a slip ratio with respect to a friction coefficient between a drive wheel and a road surface becomes a target slip ratio.

JP-A-2-38173, page 7

  However, since the slip control device disclosed in Patent Document 1 performs control based on the slip value, depending on the speed at which the slip value increases, the slip of the drive wheel cannot be sufficiently suppressed or the slip of the drive wheel is excessive. There is a risk of being suppressed. As a result, the behavior of the vehicle may change or a desired braking / driving force may not be obtained, and drivability may be reduced.

  Therefore, the present invention has been made in view of the above, and an object of the present invention is to provide a slip suppression control device that can suppress a decrease in drivability due to insufficient or excessive suppression of slip of a drive wheel. And

In order to solve the above-described problems and achieve the object, a slip suppression control device according to the present invention includes a friction parameter estimation unit that estimates a friction parameter serving as a measure of friction between a drive wheel and a road surface included in a vehicle. The friction parameter estimated by the friction parameter estimator is set as a friction parameter learning value, and the friction parameter estimated by the friction parameter estimator is estimated until the slip generated in the drive wheel starts to increase and decreases. When it is determined that the estimated parameter value is smaller than the latest friction parameter learning value, the friction parameter learning value is updated, and when the slip generated on the drive wheel is approaching convergence, the friction parameter estimation is performed. When the estimated value of the friction parameter estimated by the section is larger than the latest learned friction parameter value, A friction parameter update section for updating the friction parameter learning value, and characterized in that it comprises based on the latest of the friction parameter learning value set, a longitudinal force setting unit for setting a braking and driving force of the driving wheel, the To do.

As a desirable aspect of the present invention, in the slip suppression control device, the friction parameter update unit is configured to estimate the friction estimated by the friction parameter estimation unit until the slip generated in the drive wheel changes from increase to decrease. When it is determined that the estimated parameter value is smaller than the latest friction parameter learning value, the friction parameter learning value is calculated using a value corrected to a value smaller than the friction parameter estimated by the friction parameter estimation unit. Is preferably updated.

As a preferred aspect of the present invention, in the slip suppression control device, the friction parameter update unit estimates the friction parameter estimated by the friction parameter estimation unit when a slip generated in the drive wheel is approaching convergence. When the value is larger than the latest friction parameter learning value, it is preferable to update the friction parameter learning value using a value corrected to a value larger than the friction parameter estimated by the friction parameter estimation unit.

  According to the present invention, it is possible to suppress a decrease in drivability due to insufficient or excessive suppression of drive wheel slip.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, or those that are substantially the same, and those that are included in a so-called equivalent range.

  In the following description, a case where the present invention is applied to a vehicle using an electric motor as a power generation source, for example, a so-called electric vehicle or FCV (Fuel Cell Vehicle) will be described. A power generation source that can control the braking / driving force is sufficient. If it is such a vehicle, this invention is applicable also to what is called a hybrid vehicle which uses an electric motor and an internal combustion engine as a power generation source, and the vehicle which uses an internal combustion engine for a power generation source. In the present invention, since the slip of the drive wheel is suppressed by adjusting the torque of the power generation source, the power generation source provided in the vehicle can easily know the torque being output, such as an electric motor. In addition, it is preferable that the output torque can be changed quickly. Further, the slip of the drive wheel is a slip having an unacceptable magnitude in driving, and is a slip when the friction coefficient between the drive wheel and the road surface exceeds the maximum value.

  This embodiment is characterized by the following points. That is, in suppressing the slip of the drive wheel, the estimated value of the friction parameter is larger than the latest learned friction parameter value until the slip generated on the drive wheel starts from increasing to decreasing, that is, until the slip is converged. Only when it is small, the estimated friction parameter is set as a friction parameter learning value. In addition, when the slip generated on the drive wheel is decreasing, that is, when the slip is converging, the estimated friction parameter is obtained only when the estimated value of the friction parameter is larger than the latest learned friction parameter value. Is set as a friction parameter learning value. Here, the friction parameters are road surface reaction force, maximum road surface reaction force, friction coefficient between the drive wheel and the road surface, maximum friction coefficient between the drive wheel and the road surface, and other friction between the drive wheel and the road surface. It is a parameter that serves as a measure of size.

  In the following, the slip suppression control refers to control that suppresses slips that are not allowed to occur in the drive wheels included in the vehicle to slips within the allowable range. For example, when the road surface reaction force between the driving wheel and the road surface has a maximum value with respect to the change in the slip ratio, if the slip ratio of the driving wheel exceeds the slip ratio at the maximum road surface reaction force, the slip of the driving wheel Is not acceptable. In this case, the slip suppression control is a control for suppressing the slip ratio of the drive wheel to the slip ratio at the maximum road reaction force when the slip ratio of the drive wheel provided in the vehicle exceeds the slip ratio at the maximum road reaction force. Become.

  FIG. 1 is a schematic diagram illustrating a configuration of a vehicle including a traveling device according to the present embodiment. In the following description, the direction in which the vehicle 1 moves forward (the direction of the arrow X in FIG. 1) is the front, and the direction in which the vehicle 1 moves backward, that is, the direction opposite to the direction in which the vehicle 1 moves forward is the rear. The left / right distinction is based on the direction in which the vehicle 1 moves forward. That is, “left” refers to the left side in the direction in which the vehicle 1 moves forward, and “right” refers to the right side in the direction in which the vehicle 1 moves forward.

  The vehicle 1 according to the present embodiment includes a traveling device 100 that uses only an electric motor as a power generation source. The traveling device 100 includes a left front motor 10fl, a right front motor 10fr, a left rear motor 10rl, and a right rear motor 10rr that are power generation sources. In the present embodiment, the left front motor 10fl drives the left front wheel 2fl, the right front motor 10fr drives the right front wheel 2fr, the left rear motor 10rl drives the left rear wheel 2rl, and the right rear motor 10rr is the right side. The rear wheel 2rr is driven.

  As described above, in the traveling device 100, the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr are driven by different electric motors. Thus, the vehicle 1 is a so-called four-wheel drive type vehicle in which all the wheels, that is, the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr serve as drive wheels. Among these drive wheels, the left front wheel 2fl and the right front wheel 2fr are drive wheels of the vehicle 1, and also function as steering wheels that are steered by the handle 4 to change the traveling direction of the vehicle 1. The vehicle 1 is not limited to a vehicle having all wheels as drive wheels, and may drive only the front wheels (left front wheel 2fl and right front wheel 2fr) or rear wheels (left rear wheel 2rl and right rear wheel 2rr). Only) may be driven.

  In the traveling apparatus 100, as described above, the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr are directly driven by different electric motors. The left front motor 10fl, the right front motor 10fr, the left rear motor 10rl and the right rear motor 10rr are disposed in the wheels of the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl and the right rear wheel 2rr. It has a so-called in-wheel configuration.

  A speed reduction mechanism is provided between the motor and the wheel to reduce the rotational speed of the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr, and the left front wheel 2fl and the right front wheel 2fr. The left rear wheel 2rl and the right rear wheel 2rr may be transmitted. In general, when the electric motor is downsized, the torque decreases, but the torque of the electric motor can be increased by providing a speed reduction mechanism. As a result, the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr can be reduced in size.

  The left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr are controlled by an ECU (Electronic Control Unit) 50, and the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, the right rear wheel The braking / driving force of the wheel 2rr is adjusted. In the present embodiment, the total braking / driving force F_all of the traveling device 100 and the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr are determined by the opening of the accelerator 5 detected by the accelerator opening sensor 41. The braking / driving force of the wheel is controlled.

  In the slip suppression control according to the present embodiment, the braking / driving force of the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr is changed by the slip suppression control device 30 incorporated in the ECU 50. That is, in the slip suppression control according to the present embodiment, the slip suppression control device 30 exhibits a function as braking / driving force changing means for changing the braking / driving force of each driving wheel provided in the vehicle 1. In the present embodiment, the braking / driving forces of the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr can be independently controlled by the above-described configuration. Thus, when the slip suppression control according to the present embodiment is executed, the slips of the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr can be individually controlled.

  The left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr are rotated by the left front resolver 40fl, the right front resolver 40fr, the left rear resolver 40rl, and the right rear resolver 40rr. Is detected. The outputs of the left front resolver 40fl, the right front resolver 40fr, the left rear resolver 40rl, and the right rear resolver 40rr are captured by the ECU 50, and the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear side Used to control the electric motor 10rr.

  The left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr are connected to the inverter 6. The inverter 6 includes a left front motor inverter 6fl that drives the left front motor 10fl, a right front motor inverter 6fr that drives the right front motor 10fr, a left rear motor inverter 6rl that drives the left rear motor 10rl, and a right It is composed of a right rear motor inverter 6rr that drives the rear motor 10rr. Thus, in this embodiment, it is comprised by four inverters corresponding to each electric motor, and one electric motor is controlled by one inverter.

  An in-vehicle power source 7 such as a nickel-hydrogen battery, a lead storage battery, or a fuel cell (FC) is connected to the inverter 6, and the left front motor 10 fl and the right front side are connected via the inverter 6 as necessary. The electric power is supplied to the electric motor 10fr, the left rear electric motor 10rl, and the right rear electric motor 10rr. These outputs are controlled by controlling the inverter 6 according to a command from the ECU 50.

  When the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr are used as power generation sources of the traveling device 100, the electric power of the in-vehicle power supply 7 is supplied via the inverter 6. For example, when the vehicle 1 is decelerated, the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr function as a generator to perform regenerative power generation, thereby reducing the kinetic energy of the vehicle 1. It is converted into electrical energy, collected, and stored in the in-vehicle power source 7. This is realized by the ECU 50 controlling the inverter 6 based on a signal such as a brake signal or an accelerator off. In addition, also when performing the slip suppression control according to the present embodiment, regenerative power generation of the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr is executed as necessary.

  In the following, for convenience of explanation, the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr are referred to as drive wheels 2 without distinction as necessary. Further, the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr are referred to as the motor 10 as necessary, and the left front resolver 40fl, the right front resolver 40fr, the left rear resolver 40rl, The right rear resolver 40rr is referred to as a resolver 40 as necessary.

  FIG. 2 is a conceptual diagram for explaining a control mode in the slip suppression control. FIG. 3 is an explanatory diagram showing the relationship between the road surface reaction force and the slip ratio. FIG. 4 is a conceptual diagram illustrating wheel speed, road surface reaction force, and the like. FIG. 2 shows temporal changes in the rotational speed (called wheel speed) Vw of the drive wheel 2 and the speed (vehicle speed) Vc of the vehicle 1 during execution of the slip suppression control. Here, the wheel speed Vw is the peripheral speed of the driving wheel 2, where the rotational angular speed of the driving wheel 2 is ω (rad / sec) and the radius of the driving wheel 2 is r, Vw = r × ω. it can. Further, the vehicle speed Vc can be obtained, for example, as an average value of the wheel speeds Vw of the left front wheel 2fl, the right front wheel 2fr, the left rear wheel 2rl, and the right rear wheel 2rr.

  As shown by the solid line indicated by Fs in FIG. 3, the road surface reaction force Ftrc between the drive wheel 2 and the road surface GL included in the vehicle 1 shown in FIG. 4 is a slip ratio slip (= (Vw−Vc) / Vw. ) Will increase with the increase. The road surface reaction force Ftrc reaches a maximum value (maximum road surface reaction force) Ftrc_max at a certain slip ratio, and thereafter decreases as the slip ratio slip increases. Note that the slip ratio at the maximum road surface reaction force Ftrc_max is slip_max. Here, the road surface reaction force Ftrc is proportional to the friction coefficient μ between the driving wheel 2 and the road surface GL, and the friction coefficient when the maximum road surface reaction force Ftrc_max is μmax. Further, the road surface reaction force Ftrc is a force by which the road surface GL pushes the driving wheel 2 and has the same magnitude and opposite direction as the braking / driving force Fd of the driving wheel 2 (Fd shown in FIG. 4 is the driving force). Showing).

  When the slip ratio slip of the drive wheel 2 exceeds the slip ratio slip_max when the maximum road surface reaction force Ftrc_max is reached, an unacceptable slip occurs in the drive wheel 2, and the wheel speed Vw and the slip ratio slip increase rapidly. Here, the driving wheel 2 can generate the largest braking / driving force Fd when the maximum road surface reaction force Ftrc_max, that is, the maximum friction coefficient μmax. Therefore, in order to make the vehicle 1 travel using the grip force of the driving wheel 2 as effectively as possible, the slip ratio slip of the driving wheel 2 is controlled to be the slip ratio slip_max at the maximum road surface reaction force Ftrc_max. It is preferable. If the target slip ratio slip_tg is the target slip ratio of the drive wheels 2, the target slip ratio slip_tg becomes the slip ratio slip_max when the maximum road surface reaction force Ftrc_max is reached.

  When an unacceptable slip occurs in the drive wheel 2, the slip suppression control according to the present embodiment is executed, and the slip of the drive wheel 2 is suppressed. Also in the slip suppression control, the slip ratio slip of the drive wheel 2 is set to the target slip ratio slip_tg. In FIG. 2, the target slip ratio slip_tg is described together with the wheel speed Vw and the vehicle speed Vc. However, when the wheel speed Vw is between the target slip ratio slip_tg and the vehicle speed Vc, the slip ratio of the drive wheel 2 is shown. It is assumed that slip is smaller than the target slip rate slip_tg. That is, it is assumed that the vehicle 1 is traveling in a state where no unacceptable slip has occurred in the drive wheels 2.

  The slip suppression control according to the present embodiment changes the control in four stages depending on how the drive wheels 2 move, and is executed in the order of control mode 1, control mode 2, control mode 3, and control mode 4. The control mode 1 is a control mode in which control for reducing the torque (driving torque) Td applied to the driving wheel 2 is executed because an unacceptable slip occurs on the driving wheel 2 and the grip to the road surface GL is lost. . In the control mode 1, as shown in FIG. 2, the wheel speed Vw increases rapidly, but the drive torque Td decreases. The rise of Vw stops. Thereafter, the wheel speed Vw starts to decrease, the slip of the drive wheel 2 is converged, and the grip of the drive wheel 2 is recovered. Here, in the control mode 1, the acceleration (wheel acceleration) a = dω / dt of the driving wheel 2 is positive, and the wheel acceleration a becomes 0 when the increase in the wheel speed Vw is stopped. Here, the wheel acceleration a is the rotational angular acceleration.

  The control mode 2 is executed when the slip of the drive wheel 2 tends to converge, that is, when the increase of the wheel speed Vw of the drive wheel 2 stops and starts to decrease. That is, the control mode 2 is executed from when the wheel acceleration a turns negative. In this case, since the slip of the drive wheel 2 has started to converge and the drive wheel 2 has started to recover the grip with the road surface GL, the control mode 2 increases the drive torque according to the slip state of the drive wheel 2. Control mode.

  The control mode 3 is executed in a state where the slip of the driving wheel 2 has converged and the driving wheel 2 has recovered the grip with the road surface GL. The control mode 3 is a control mode that waits until the vibration generated in the drive wheel 2 and its drive system falls within an allowable range due to a shock when the drive wheel 2 recovers the grip with the road surface GL. The control mode 4 is a control mode for grasping the state of the road surface GL while gradually increasing the driving torque and calculating the road surface reaction force Ftrc. As shown in FIG. 3, the control mode 1 and the control mode 2 are control modes when the slip ratio slip of the driving wheel 2 is larger than slip_tg, and the control mode 3 and the control mode 4 are the slip ratio of the driving wheel 2. This is a control mode when slip is smaller than slip_tg.

In the slip suppression control, a decrease amount or an increase amount of the drive torque is set based on the maximum road surface reaction force Ftrc_max. For this reason, in the slip suppression control, the maximum road reaction force Ftrc_max is always estimated between the control mode 1 and the control mode 4, and the driving torque is set using the latest Ftrc_max. Here, a method of estimating the maximum road surface reaction force Ftrc_max will be described. The road surface reaction force Ftrc can be obtained by Expression (1).
Ftrc = (Td × RD−Iv × a) / r (1)
Note that Iv is inertia of the drive system including inertia of the drive wheel 2, RD is a reduction ratio, and a is wheel acceleration, and is expressed by rotational angular acceleration as described above. Further, the inertia Iv of the drive system is, for example, the inertia of all structures related to power transmission existing between the rotor of the electric motor 10 and the drive wheels 2 in the vehicle 1 according to the present embodiment.

  In the present embodiment, the driving torque Td is acquired while the vehicle 1 is traveling, and the road surface reaction force Ftrc is obtained from the equation (1). When the road surface reaction force deviation ΔFtrc obtained by subtracting the previous value Ftrc (n−1) of the road surface reaction force from the current value Ftrc (n) of the road surface reaction force becomes negative, the maximum road surface reaction force Ftrc_max is It is estimated that the previous value Ftrc (n-1) of the force. In the present embodiment, the maximum road surface reaction force Ftrc_max estimated in this way is set as a friction parameter learning value (maximum road surface reaction force learning value) Ftrcm, and is used for the slip suppression control according to the present embodiment.

Next, update of the maximum road surface reaction force learning value Ftrcm during the slip suppression control will be described. In the slip suppression control according to the present embodiment, the maximum road surface reaction force Ftrc_max is estimated during the execution of the slip suppression control. Here, the acceleration A_g of the drive wheel 2 required when the set time Δt is required until the grip wheel is recovered after the drive wheel 2 slips is expressed by Expression (2). A_g is an estimated value. Here, the set time Δt may be a predetermined value set in advance or may be changed according to the slip rate slip. For example, the set time Δt may be set such that as the slip rate slip increases, the set time Δt is shortened so that the slip converges more rapidly as the slip of the drive wheel 2 increases.
A_g = − (Vw−V / (1-slip_max)) × 1000/3600 / Δt / r (2)
Here, slip_max in the equation (2) is a slip ratio corresponding to the latest maximum road surface reaction force learning value Ftrcm.

When the actual acceleration of the driving wheel 2 is A_r, the road surface reaction force correction value (corrected road surface reaction force) Ftrc_c is expressed by Expression (3).
Ftrc_c = | A_r−A_g | × Iv / r (3)

  When A_g> A_r, the latest maximum road surface reaction force learning value Ftrcm that is set is lower than the maximum road surface reaction force Ftrc_max estimated from the actual acceleration of the drive wheels 2 from A_r. In this case, the slip suppression control device 30 shown in FIG. 1 estimates a value (Ftrcm + Ftrc_c) obtained by adding the corrected road surface reaction force Ftrc_c obtained by the expression (3) to the latest maximum road surface reaction force learning value Ftrcm that is set. The maximum road surface reaction force (estimated maximum road surface reaction force) Ftrc_max_g. The slip suppression control device 30 sets the estimated maximum road surface reaction force Ftrc_max_g (= Ftrcm + Ftrc_c) as the maximum road surface reaction force used for the slip suppression control, and updates the latest maximum road surface reaction force learning value Ftrcm to the estimated maximum road surface reaction force Ftrc_max_g. To do. Thus, when A_g> A_r, the current value Ftrcm_n of the maximum road surface reaction force learning value is larger than the previous value Ftrcm_l of the maximum road surface reaction force learning value.

  When A_g <A_r, the set latest maximum road surface reaction force learning value Ftrcm is higher than the maximum road surface reaction force Ftrc_max_r estimated from the actual acceleration of the drive wheels 2 from A_r. In this case, a value (Ftrcm−Ftrc_c) obtained by subtracting the corrected road surface reaction force Ftrc_c obtained by the expression (3) from the set latest maximum road surface reaction force learning value Ftrcm is the slip suppression control device 30 shown in FIG. Is the estimated maximum road surface reaction force Ftrc_max_g. The slip suppression control device 30 sets the estimated maximum road surface reaction force Ftrc_max_g (= Ftrcm−Ftrc_c) as the maximum road surface reaction force used for the slip suppression control, and sets the latest maximum road surface reaction force learning value Ftrcm as the estimated maximum road surface reaction force Ftrc_max_g. Update to Thus, when A_g <A_r, the current value Ftrcm_n of the maximum road surface reaction force learning value is smaller than the previous value Ftrcm_l of the maximum road surface reaction force learning value.

  When A_g = A_r, the latest maximum road surface reaction force learning value Ftrcm that is set is the same value as the maximum road surface reaction force Ftrc_max_r in which the actual acceleration of the drive wheels 2 is estimated from A_r. In this case, the set latest maximum road surface reaction force learning value Ftrcm is the estimated maximum road surface reaction force Ftrc_max_g estimated by the slip suppression control device 30 shown in FIG. In this case, the maximum road surface reaction force learning value Ftrcm is not updated, and the previous maximum road surface reaction force learning value Ftrcm is continuously set as the maximum road surface reaction force used for the slip suppression control. As described above, when A_g = A_r, the previous value Ftrcm_l of the maximum road surface reaction force learning value is equal to the current value Ftrcm_n of the maximum road surface reaction force learning value.

  When the maximum road surface reaction force is estimated and updated to the latest maximum road surface reaction force learning value Ftrcm during the slip suppression control, the estimated maximum road surface reaction force Ftrc_max_g changes according to the vibration of the drive wheel 2 or its drive system. End up. Even when no vibration is generated in the drive wheel 2 or its drive system, the estimation accuracy of the maximum road surface reaction force learning value Ftrcm and the corrected road surface reaction force Ftrc_c decreases due to the communication delay of the ECU 50 and the presence of the calculation cycle. Thus, the estimated maximum road surface reaction force Ftrc_max_g may be different from the actual maximum road surface reaction force Ftrc_max.

  In the control mode 1 described above, the drive torque should be reduced more than before in order to suppress the slip of the drive wheel 2. However, when the maximum road surface reaction force is estimated to be higher than the actual value, if the drive torque is controlled using the maximum road surface reaction force learning value Ftrcm updated with this estimated value, the slip of the drive wheels 2 will increase. Further, in the control mode 2, the slip tends to converge, and the driving force of the driving wheel 2 is efficiently accelerated so that the driving force of the driving wheel 2 becomes the maximum road surface reaction force Ftrc_max by applying an appropriate driving torque to the driving wheel 2. Should go. However, when the maximum road surface reaction force is estimated to be lower than the actual value, if the drive torque is controlled using the maximum road surface reaction force learning value Ftrcm updated with this estimated value, an appropriate drive torque can be applied to the drive wheels 2. This is not possible, and the driver of the vehicle 1 is given a feeling of stall. As described above, if the maximum road surface reaction force is appropriately estimated and cannot be set as the maximum road surface reaction force learning value Ftrcm, drivability decreases due to insufficient or excessive slip suppression of the drive wheels 2. May be incurred.

  In the slip suppression control according to the present embodiment, the following means are used to avoid the above problem. First, in the control mode 1, the maximum road surface reaction force learning value Ftrcm is updated only when it is determined that the estimated maximum road surface reaction force Ftrc_max_g is smaller than the latest maximum road surface reaction force learning value Ftrcm. That is, in the control mode 1, the maximum road surface reaction force learning value Ftrcm is updated only in the direction in which the maximum road surface reaction force learning value Ftrcm decreases.

  As described above, in the control mode 1, since the drive wheel 2 slips, it is necessary to reliably and sufficiently reduce the drive torque in order to converge the slip at an early stage. If the maximum road surface reaction force is estimated to be higher than actual, the amount of decrease in the drive torque is small, or the drive torque increases on the contrary, and the slip of the drive wheel 2 does not converge. However, when the maximum road surface reaction force is estimated to be lower than the actual value, the amount of decrease in the drive torque is larger than when the maximum road surface reaction force is an actual value. It can be converged. Thereby, the slip of the drive wheel 2 can be reliably and quickly converged, and the behavior of the vehicle 1 can be stabilized at an early stage.

  In the present embodiment, in the control mode 1, the estimated maximum road surface reaction force Ftrc_max_g estimated by the slip suppression control device 30 shown in FIG. 1 is corrected to a smaller value and updated as the latest maximum road surface reaction force learning value Ftrcm. It is preferable to do. That is, it is preferable to update a value k1 × Ftrc_max_g obtained by multiplying the estimated maximum road surface reaction force Ftrc_max_g by a correction coefficient k1 larger than 0 and smaller than 1 as the latest maximum road surface reaction force learning value Ftrcm. As a result, the amount of decrease in the drive torque becomes larger, so that the slip of the drive wheel 2 can be converged more quickly. As a result, the slip of the drive wheel 2 can be converged more reliably and quickly, and the behavior of the vehicle 1 can be stabilized earlier.

  Next, in the control mode 2, the maximum road surface reaction force learning value Ftrcm is updated only when it is determined that the estimated maximum road surface reaction force Ftrc_max_g is larger than the latest maximum road surface reaction force learning value Ftrcm_l. That is, in the control mode 2, the maximum road surface reaction force learning value Ftrcm is updated only in the direction in which the maximum road surface reaction force learning value Ftrcm increases.

  As described above, in the control mode 2, the slip of the drive wheel 2 tends to converge, so it is necessary to accelerate the vehicle 1 by applying an appropriate drive torque to the drive wheel 2. Here, in the control mode 1, the estimated maximum road surface reaction force Ftrc_max_g is set as the maximum road surface reaction force learning value Ftrcm only when the estimated maximum road surface reaction force Ftrc_max_g is smaller than the latest maximum road surface reaction force learning value Ftrcm_l. Therefore, the latest maximum road surface reaction force learning value Ftrcm is always smaller than the actual maximum road surface reaction force. Here, if the maximum road reaction force is estimated to be lower than actual, the amount of increase in the drive torque is small, or conversely, the drive torque decreases, so that there is not enough torque to give the vehicle 1 an appropriate acceleration. However, there is a high possibility that the driver of the vehicle 1 will feel stalled.

  However, when the maximum road surface reaction force is estimated to be higher than the actual value, the amount of increase in drive torque is greater than when the maximum road surface reaction force is estimated to be an actual value. For this reason, it is possible to drive the driving wheel 2 with a value closer to the actual maximum road surface reaction force and to give an appropriate acceleration to the vehicle 1. As a result, the behavior of the vehicle 1 can be stabilized and the feeling of stalling given to the driver of the vehicle 1 can be avoided.

  In the present embodiment, in the control mode 2, the estimated maximum road surface reaction force Ftrc_max_g estimated by the slip suppression control device 30 shown in FIG. 1 is corrected to a larger value and updated as the latest maximum road surface reaction force learning value Ftrcm. It is preferable to do. That is, it is preferable to update a value k2 × Ftrc_max_g obtained by multiplying the estimated maximum road surface reaction force Ftrc_max_g by a correction coefficient k2 larger than 1 as the latest maximum road surface reaction force learning value Ftrcm. As a result, the increase amount of the drive torque becomes larger, so that the drive wheels 2 can be driven more quickly with a value close to the actual maximum road surface reaction force. As a result, appropriate acceleration can be given to the vehicle 1 more quickly, so that the behavior of the vehicle 1 can be stabilized more quickly and the feeling of stalling given to the driver of the vehicle 1 can be more reliably avoided. be able to.

  FIG. 5 is a conceptual diagram showing temporal changes in the estimated value of the road surface reaction force, the command value of the driving torque, the wheel speed and the like in the slip suppression control. The upper part (A) of FIG. 5 shows the slip suppression control when the maximum road surface reaction force is ideally estimated, and the middle part (B) of FIG. 5 shows that the estimated value of the maximum road surface reaction force fluctuated. The slip suppression control in the case is shown. Further, the lower part (C) of FIG. 5 shows the slip suppression control according to the present embodiment.

  When the maximum road surface reaction force is ideally estimated, as shown in the upper part (A) of FIG. 5, the maximum road surface reaction after the occurrence of slip on the drive wheel 2 shown in FIG. The force is constant at Ftrc_max_i. When the drive wheel 2 slips, slip suppression control is started. The control mode 1 is from t = 1 to t = 9, the control mode 2 is from t = 9 to t = 10, the control mode 3 is from t = 10 to t = 11, and after t = 11. This is control mode 4.

  When the maximum road surface reaction force is ideally estimated, the slip suppression control device 30 illustrated in FIG. 1 reduces the drive torque Td of the drive wheels 2 based on the estimated maximum road surface reaction force Ftrc_max_i. When the maximum road reaction force is ideally estimated, the slip suppression control device 30 drives the drive wheels 2 with a drive torque command value (drive torque command value) Ts_i as shown in the upper part (A) of FIG. Control torque.

  Accordingly, when the maximum road reaction force is ideally estimated, the wheel speed changes as Vw_i, and the vehicle speed changes as Vc. As a result, in the slip suppression control, the slip ratio slip of the drive wheel 2 is controlled to be the target slip ratio slip_tg.

  However, actually, as shown in the middle part (B) of FIG. 5, the estimated value of the maximum road surface reaction force (estimated maximum road surface reaction force Ftrc_max_g) varies, and as a result, the maximum road surface updated by the estimated maximum road surface reaction force Ftrc_max_g. The reaction force learning value Ftrcm also varies. For this reason, the drive torque command value Ts for the electric motor 10 determined based on the varying maximum road surface reaction force learning value Ftrcm also varies as shown in the middle part (B) of FIG. Thereby, in the control mode 1, when the maximum road surface reaction force learning value Ftrcm is estimated to be large (near t = 3 or near t = 7), the drive torque command value Ts also increases. As a result, re-slip occurs in the drive wheel 2 at a portion indicated by S in the middle part (B) of FIG.

  In the slip suppression control according to the present embodiment, as shown in the lower part (C) of FIG. 5, in the control mode 1, it is determined that the estimated maximum road surface reaction force Ftrc_max_g is smaller than the latest maximum road surface reaction force learning value Ftrcm. Only when the maximum road surface reaction force learning value Ftrcm is updated. For example, between t = 1.5 and t = 4.5 or between t = 5 and t = 9, the maximum road surface reaction force learning value Ftrcm is larger than the previous value, so that the maximum road surface reaction force learning is performed. The value Ftrcm is not updated. As a result, in the example shown in the middle part (B) of FIG. 5, the re-slip generated in the drive wheel 2 does not occur, and the slip of the drive wheel 2 is quickly suppressed. Next, the slip suppression control device 30 according to this embodiment will be described.

  FIG. 6 is an explanatory diagram illustrating a configuration example of the slip suppression control device according to the present embodiment. As shown in FIG. 6, the slip suppression control device 30 is configured to be incorporated in the ECU 50. The ECU 50 includes a CPU (Central Processing Unit) 50p, a storage unit 50m, an input port 55 and an output port 56, and an input interface 57 and an output interface 58.

  In addition, separately from ECU50, the slip suppression control apparatus 30 which concerns on this embodiment may be prepared, and this may be connected to ECU50. And in implement | achieving the slip suppression control which concerns on this embodiment, you may comprise so that the said slip suppression control apparatus 30 can utilize the control function with respect to the traveling apparatus 100 etc. with which ECU50 is provided.

  The slip suppression control device 30 includes a control condition determination unit 31, a friction parameter estimation unit 32, a friction parameter update unit 33, and a braking / driving force control unit 34. These are the parts that execute the slip suppression control according to the present embodiment. In the present embodiment, the slip suppression control device 30 is configured as a part of the CPU 50p configuring the ECU 50.

The control condition determination unit 31, the friction parameter estimation unit 32, the friction parameter update unit 33, and the braking / driving force control unit 34 of the slip suppression control device 30 include a bus 54 ₁ , a bus 54 ₂ , an input port 55, and an output. Connection is made via port 56. As a result, the control condition determination unit 31, the friction parameter estimation unit 32, and the friction parameter update unit 33 constituting the slip suppression control device 30 can exchange control data with each other or issue commands to one side. Configured.

Further, a slip suppression control device 30 provided in the CPU 50p, and the storage unit 50m, are connected via a bus 54 _3. Thereby, the slip suppression control device 30 can acquire the operation control data of the traveling device 100 included in the ECU 50 and can use it. Further, the slip suppression control device 30 can cause the slip suppression control according to the present embodiment to interrupt an operation control routine that the ECU 50 has in advance.

  An input interface 57 is connected to the input port 55. The input interface 57 includes a left front resolver 40fl, a right front resolver 40fr, a left rear resolver 40rl, a right rear resolver 40rr, an accelerator opening sensor 41, and other sensors that acquire information necessary for operation control of the traveling device 100. Is connected.

  Signals output from these sensors are converted into signals that can be used by the CPU 50 p by the A / D converter 57 a and the digital input buffer 57 d in the input interface 57 and sent to the input port 55. Thereby, CPU50p can acquire the information required for the driving | running control of the traveling apparatus 100, and the slip suppression control which concerns on this embodiment.

An output interface 58 is connected to the output port 56. A control target necessary for slip suppression control is connected to the output interface 58. In the present embodiment, the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl and the inverter 6 for controlling the right rear motor 10rr, that is, the left front motor inverter 6fl, the right front motor inverter 6fr, The left rear motor inverter 6rl and the right rear motor inverter 6rr are control targets necessary for the slip suppression control according to the present embodiment. The output interface 58 includes control circuits 58 ₁ , 58 _{2 and the} like, and operates the control target based on a control signal calculated by the CPU 50p. With this configuration, the CPU 50p of the ECU 50 controls the braking / driving force of the left front motor 10fl, the right front motor 10fr, the left rear motor 10rl, and the right rear motor 10rr based on the output signals from the sensors. Can do.

  The storage unit 50m stores a computer program including a processing procedure of slip suppression control according to the present embodiment, a control map, a data map used for slip suppression control according to the present embodiment, and the like. Here, the storage unit 50m can be configured by a volatile memory such as a RAM (Random Access Memory), a nonvolatile memory such as a flash memory, or a combination thereof.

  The computer program may be capable of realizing the processing procedure of the slip suppression control according to the present embodiment in combination with the computer program already recorded in the CPU 50p. The slip suppression control device 30 uses functions of the control condition determination unit 31, the friction parameter estimation unit 32, the friction parameter update unit 33, and the braking / driving force control unit 34 using dedicated hardware instead of the computer program. May be realized. Next, the slip suppression control according to the present embodiment will be described. The slip suppression control according to the present embodiment can be realized by the slip suppression control device 30 described above.

  7 to 9 are flowcharts showing the procedure of the slip suppression control according to the present embodiment. In executing the slip suppression control according to the present embodiment, in step S101, the control condition determination unit 31 included in the slip suppression control device 30 determines whether or not slip has occurred in the drive wheels 2 of the vehicle 1 shown in FIG. judge. For example, when the peak value of the road surface reaction force Ftrc, that is, the maximum road surface reaction force Ftrc_max is detected, the control condition determination unit 31 determines that slip has occurred in the drive wheels 2.

  Alternatively, when a slip ratio slip exceeding the target slip ratio slip_tg is detected, the control condition determination unit 31 determines that a slip has occurred in the drive wheel 2. Here, the vehicle 1 shown in FIG. 1 includes a plurality of drive wheels 2, but when a slip of at least one drive wheel is detected, the slip suppression control device 30 suppresses slip with respect to the drive wheels 2. Execute control. When slip occurs in the drive wheel 2, the friction parameter update unit 33 included in the slip suppression control device 30 uses the maximum road surface reaction force Ftrc_max detected by the control condition determination unit 31 as the latest maximum road surface reaction force learning value Ftrcm. And is stored in the storage unit 50m.

  Here, the maximum road surface reaction force Ftrc_max is estimated by the friction parameter estimation unit 32 provided in the slip suppression control device 30. The friction parameter estimation unit 32 sets the drive torque Td obtained based on the drive torque command value Ts for the motor 10, the drive current value of the motor 10, and the like, and the rotational angular velocity (wheel angular velocity) ω of the drive wheel 2 obtained from the resolver 40. The maximum road surface reaction force Ftrc_max is estimated from the wheel acceleration a determined based on the above (see Expression (1)). Further, the friction parameter estimation unit 32 sets the slip ratio when the maximum road surface reaction force Ftrc_max is set as the target slip ratio slip_tg. The slip ratio slip of the drive wheel 2 is obtained by the friction parameter estimation unit 32 based on the wheel speed Vw and the vehicle speed Vc obtained from the wheel angular speed ω of the drive wheel 2 acquired from the resolver 40.

  When it is determined No in step S101, that is, when no slip has occurred in the drive wheel 2, the slip suppression control ends, and the control condition determination unit 31 continues to monitor the slip of the drive wheel 2. . When it is determined Yes in step S101, that is, when a slip has occurred in at least one of the plurality of drive wheels 2 included in the vehicle 1, the process proceeds to step S102, and the slip suppression control according to the present embodiment is executed. Is done.

  In step S102, the braking / driving force control unit 34 included in the slip suppression control device 30 controls the braking / driving force of the drive wheels 2 in the control mode 1 of the slip suppression control. That is, based on the latest maximum road surface reaction force learning value Ftrcm, the drive torque command value Ts of the motor 10 that drives the drive wheels 2 is calculated, and the motor 10 is driven via the inverter 6. As a result, the drive torque Td of the drive wheel 2 is reduced, and control is performed so that the slip (slip rate slip) of the drive wheel 2 changes from increasing to decreasing.

  Here, the procedure for updating the maximum road surface reaction force learning value Ftrcm in the control mode 1 will be described with reference to FIG. In step S201, the friction parameter estimation unit 32 included in the slip suppression control device 30 calculates an estimated maximum road surface reaction force Ftrc_max_g. As described above, the estimated maximum road surface reaction force Ftrc_max_g can be obtained from the corrected road surface reaction force Ftrc_c and the maximum road surface reaction force learning value Ftrcm obtained by Expression (3).

  When the estimated maximum road surface reaction force Ftrc_max_g is obtained, the process proceeds to step S202. In step S202, the friction parameter updating unit 33 included in the slip suppression control device 30 compares the estimated maximum road surface reaction force Ftrc_max_g with the latest maximum road surface reaction force learning value Ftrcm_l at the present time. When it is determined Yes in step S202, that is, when the estimated maximum road surface reaction force Ftrc_max_g is smaller than the latest maximum road surface reaction force learning value Ftrcm_l at the current time, the process proceeds to step S203. In step S203, the friction parameter updating unit 33 sets the estimated maximum road surface reaction force Ftrc_max_g estimated in step S201 to the maximum road surface reaction force learning value Ftrcm, and updates the maximum road surface reaction force learning value Ftrcm.

  When it is determined No in step S202, that is, when the estimated maximum road surface reaction force Ftrc_max_g is equal to or greater than the latest maximum road surface reaction force learning value Ftrcm_l at the current time, the process proceeds to step S204. In step S204, the friction parameter updating unit 33 sets the latest maximum road surface reaction force learning value Ftrcm_l at the current time to the maximum road surface reaction force learning value Ftrcm. That is, the maximum road surface reaction force learning value Ftrcm is not updated, and the latest road surface reaction force learning value Ftrcm_l at the current time is maintained as the maximum road surface reaction force learning value Ftrcm. Next, returning to FIG. 7, the slip suppression control according to the present embodiment will be described.

  In step S103, the control condition determination unit 31 determines whether or not the wheel acceleration a has changed from positive to negative. The wheel acceleration a can be obtained by one-time differentiation of the wheel angular velocity ω (or the wheel velocity Vw). Here, during the slip suppression control, the wheel angular velocity ω also vibrates due to the vibration of the drive wheel 2. The wheel angular velocity ω increases or decreases as a whole while vibrating.

  For this reason, when determining whether or not the wheel acceleration a has changed from positive to negative, for example, a filter technique such as a digital low-pass filter is used as the vibration removing means, and the wheel angular velocity ω from which vibration is removed is used. May be. Thereby, the change of the wheel acceleration a can be determined reliably.

  Here, in step S103, determination is made when the slip suppression control is switched from the control mode 1 to the control mode 2. That is, the timing at which the slip of the drive wheels 2 has changed from increasing to decreasing is determined. In determining this timing, for example, when the vibration of the wheel angular velocity ω is detected for three cycles, it may be determined that the slip of the drive wheel 2 has changed from increasing to decreasing.

  When it is determined No in step S103, that is, when the control condition determination unit 31 determines that the wheel acceleration a is positive, the slip (slip rate slip) of the drive wheels 2 is increased, so the control mode Continue 1 If it is determined Yes in step S103, that is, if the control condition determination unit 31 determines that the wheel acceleration a is negative, the slip (slip rate slip) of the drive wheels 2 has started to decrease, so step S104 To go to control mode 2 of slip suppression control.

  In step S104, the braking / driving force control unit 34 controls the braking / driving force of the drive wheels 2 in the control mode 2 of the slip suppression control. That is, the braking / driving force control unit 34 calculates the drive torque command value Ts of the electric motor 10 that drives the driving wheel 2 based on the latest maximum road surface reaction force learning value Ftrcm, and drives the electric motor 10 via the inverter 6. . As a result, the drive torque Td is increased according to the slip state of the drive wheels 2.

  Here, a procedure for updating the maximum road surface reaction force learning value Ftrcm in the control mode 2 will be described with reference to FIG. In step S301, the friction parameter estimating unit 32 obtains an estimated maximum road surface reaction force Ftrc_max_g. When the estimated maximum road surface reaction force Ftrc_max_g is obtained, the process proceeds to step S302. In step S302, the friction parameter updating unit 33 included in the slip suppression control device 30 compares the estimated maximum road surface reaction force Ftrc_max_g with the latest maximum road surface reaction force learning value Ftrcm_l at the present time.

  If it is determined Yes in step S302, that is, if the estimated maximum road surface reaction force Ftrc_max_g is larger than the latest maximum road surface reaction force learning value Ftrcm_l at the current time, the process proceeds to step S303. In step S303, the friction parameter updating unit 33 sets the estimated maximum road surface reaction force Ftrc_max_g estimated in step S301 to the maximum road surface reaction force learning value Ftrcm, and updates the maximum road surface reaction force learning value Ftrcm.

  When it is determined No in step S302, that is, when the estimated maximum road surface reaction force Ftrc_max_g is equal to or less than the latest maximum road surface reaction force learning value Ftrcm_l at the current time, the process proceeds to step S304. In step S304, the friction parameter updating unit 33 sets the latest maximum road surface reaction force learning value Ftrcm_l at the current time to the maximum road surface reaction force learning value Ftrcm. That is, the maximum road surface reaction force learning value Ftrcm is not updated, and the latest road surface reaction force learning value Ftrcm_l at the current time is maintained as the maximum road surface reaction force learning value Ftrcm. Next, returning to FIG. 7, the slip suppression control according to the present embodiment will be described.

  In step S105, the control condition determination unit 31 determines whether or not the current slip rate slip is smaller than the target slip rate slip_tg. When it is determined No in step S105, that is, when the control condition determining unit 31 determines that slip ≧ slip_tg, the process proceeds to step S106. In step S106, the control condition determination unit 31 determines whether or not the wheel acceleration a has changed from negative to positive.

  When it determines with Yes in step S106, ie, when the control condition determination part 31 determines with the wheel acceleration a having changed from negative to positive, it determines with the slip (slip rate slip) of the driving wheel 2 increasing. it can. In this case, the control mode 1 is returned to, and the braking / driving force control unit 34 controls the driving torque Td of the driving wheel 2 to be decreased so that the slip (slip rate slip) of the driving wheel 2 starts to decrease.

  When it is determined No in step S106, that is, when the control condition determination unit 31 determines that the wheel acceleration a remains negative, it can be determined that the slip (slip rate slip) of the drive wheels 2 is decreasing. . In this case, returning to the control mode 2, the braking / driving force control unit 34 increases the driving torque Td according to the slip state of the driving wheel 2.

  When it determines with Yes at step S105, ie, when the control condition determination part 31 determines with it being slip <slip_tg, it progresses to step S107. In step S107, the braking / driving force control unit 34 controls the braking / driving force of the drive wheels 2 in the control mode 3 of the slip suppression control. That is, the braking / driving force control unit 34 stands by until the vibration generated in the drive wheel 2 and its drive system falls within the allowable range when the drive wheel 2 recovers the grip with the road surface GL.

  In step S108, the control condition determination unit 31 determines whether or not the vibration of the drive wheel 2 is within an allowable range. The vibration of the drive wheel 2 can be estimated from the fluctuation cycle of the wheel angular velocity ω (or the wheel velocity Vw). The vibration of the drive wheel 2 is vibration generated in the drive wheel 2 due to a shock when the drive wheel 2 recovers the grip with the road surface GL. When it determines with No by step S108, ie, when the control condition determination part 31 determines with the vibration of the drive wheel 2 being unacceptable, it progresses to step S109.

  In step S109, the control condition determination unit 31 determines whether or not the slip of the drive wheels 2 has increased. This can be determined by whether or not the slip ratio slip of the drive wheel 2 is increased. For example, if the difference (slip_n-slip_l) between the current value slip_n and the previous value slip_l of the slip rate slip of the drive wheel 2 is positive, it can be determined that the slip rate slip has increased.

  When it is determined Yes in step S109, that is, when the control condition determination unit 31 determines that the slip is increasing, the control mode 1 is returned to, and the braking / driving force control unit 34 drives the drive torque Td of the drive wheels 2. Is controlled so that the slip (slip rate slip) of the drive wheel 2 starts from increasing to decreasing. When it is determined No in step S109, that is, when the control condition determining unit 31 determines that the slip is decreasing, the control mode 3 is returned to, and the braking / driving force control unit 34 determines that the driving wheel 2 is the road surface GL. It waits until the vibration which generate | occur | produces in the drive wheel 2 or its drive system when it has recovered the grip of this falls within an allowable range.

  When it determines with Yes at step S109, ie, when the control condition determination part 31 determines with the vibration of the driving wheel 2 being permissible, it progresses to step S110. In step S110, the braking / driving force control unit 34 controls the braking / driving force of the drive wheels 2 in the control mode 4 of the slip suppression control. That is, the braking / driving force control unit 34 grasps the state of the road surface GL while gradually increasing the driving torque Td and calculating the road surface reaction force Ftrc.

  As described above, in the present embodiment, when the slip of the drive wheel is suppressed, the estimated value of the maximum road surface reaction force is greater than the latest maximum road surface reaction force learning value until the slip generated on the drive wheel turns from an increase to a decrease. Only when it is smaller, the estimated maximum road surface reaction force is set as the maximum road surface reaction force learning value and updated. In addition, when the slip generated on the drive wheels is decreasing, the estimated maximum road reaction force is calculated only when the estimated value of the maximum road reaction force is greater than the latest maximum road reaction force learning value. Set as learning value and update. As a result, it is possible to suppress a decrease in drivability due to insufficient or excessive suppression of slipping of the drive wheels.

  As described above, the slip suppression control device according to the present invention is useful for suppressing drive wheel slip, and in particular, drivability degradation due to insufficient or excessive suppression of drive wheel slip. It is suitable for suppressing.

It is the schematic which shows the structure of a vehicle provided with the traveling apparatus which concerns on this embodiment. It is a conceptual diagram for demonstrating the control mode in slip suppression control. It is explanatory drawing which shows the relationship between a road surface reaction force and a slip ratio. It is a key map explaining wheel speed, road surface reaction force, etc. It is a conceptual diagram which shows temporal changes of the estimated value of road surface reaction force, the command value of drive torque, wheel speed, etc. in slip suppression control. It is explanatory drawing which shows the structural example of the slip suppression control apparatus which concerns on this embodiment. It is a flowchart which shows the procedure of the slip suppression control which concerns on this embodiment. It is a flowchart which shows the procedure of the slip suppression control which concerns on this embodiment. It is a flowchart which shows the procedure of the slip suppression control which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Drive wheel 4 Handle 5 Accelerator 6 Inverter 7 In-vehicle power supply 10 Electric motor 30 Slip suppression control device 31 Control condition judgment part 32 Friction parameter estimation part 33 Friction parameter update part 34 Braking / driving force control part 40 Resolver 41 Accelerator opening degree sensor 50 ECU
50m storage unit 50p CPU
100 travel device

Claims (3)

A friction parameter estimator that estimates a friction parameter that is a measure of friction between a driving wheel and a road surface included in the vehicle;
The friction parameter estimated by the friction parameter estimator is set as a friction parameter learning value, and the friction parameter estimated by the friction parameter estimator until the slip generated on the drive wheel starts from increasing to decreasing. The friction parameter learning value is updated when it is determined that the estimated value is smaller than the latest friction parameter learning value, and the slip generated on the drive wheel is approaching convergence, the friction parameter estimation unit A friction parameter update unit that updates the friction parameter learning value when the estimated value of the friction parameter estimated by the method is larger than the latest friction parameter learning value ;
A braking / driving force setting unit that sets the braking / driving force of the driving wheel based on the latest learned friction parameter learning value,
A slip suppression control device comprising: The friction parameter updating unit
Until it is determined that the estimated value of the friction parameter estimated by the friction parameter estimation unit is smaller than the latest friction parameter learning value until the slip generated in the drive wheel starts from increasing to decreasing. The slip suppression control device according to claim 1, wherein the friction parameter learning value is updated using a value corrected to a value smaller than the friction parameter estimated by the friction parameter estimation unit. The friction parameter updating unit
When the slip generated on the drive wheel is converging, the friction parameter estimation unit estimates when the friction parameter estimation value estimated by the friction parameter estimation unit is larger than the latest friction parameter learning value. using a value obtained by correcting a value greater than the friction parameters, slip suppression control apparatus according to claim 1 or 2, characterized in that updating the friction parameter learning value.

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