JP2008240519A - Driving force control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress not only a driving force estimated that it is excessive at the moment or but also a driving force it will be excessive in the near future, and appropriately keeping a grip force of a tire to improve a running stability of a vehicle, regardless of being attached/unattached with a tire chain. <P>SOLUTION: A driving force control device 1 calculates a friction circle limit value of each wheel, calculating a required tire resultant force of each wheel, calculating a tire resultant force of each tire, calculating a required over tire force of each wheel, calculating an over tire force of each wheel, calculating over torque by calculating the over tire force, and thereby calculates controlled variables. A first correction amount acquired based on an attached state of the tire chain and a vehicle body slide angular speed is compared with a second correction value acquired for suppressing slip of a vehicle wheel by theoretical fore-aft acceleration and actual fore-aft acceleration, a larger correction amount is subtracted to correct the controlled variables, and the corrected controlled variables are output to an engine control part 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving force control device for a vehicle that controls driving force so as to appropriately maintain a grip force of a wheel.

  In recent years, various driving force control devices that suppress excessive driving force in order to maintain wheel grip force have been developed and put into practical use in vehicles.

For example, in Japanese Patent Laid-Open No. 10-310042, an estimated value of the friction circle radius of each wheel is obtained, and each wheel estimated according to the running state of the vehicle is generated within a range not exceeding the estimated value of the friction circle radius. A technique for adjusting the resultant force between the lateral force and the longitudinal force is disclosed.
JP 10-310042 A

  However, in the technique disclosed in Patent Document 1 described above, the resultant force of the lateral force and the longitudinal force that are currently generated is to be included in the estimated value of the friction circle radius, and driving that is expected to occur in the future. There is a problem that power cannot be effectively dealt with. For this reason, although it can respond appropriately when the vehicle is currently in a spin state, there is a problem that it cannot properly respond to a plow state or the like. In addition, in order to properly maintain the grip force of the wheel, it is necessary to consider the mounting of a tire chain on the wheel. In other words, if the control takes into account only the tire force of the wheel without the tire chain, the tire force of the wheel with the tire chain will not be fully utilized, causing problems such as not accelerating while stepping on the accelerator. If the control is performed considering only the tire force of the wheels, there is a problem in that the stability of the wheels not equipped with the tire chain is lowered.

  The present invention has been made in view of the above circumstances, and suppresses an excessive driving force estimated to occur not only at the present time but also in the future regardless of whether the tire chain is attached or not, and appropriately adjusts the tire grip force. An object of the present invention is to provide a vehicle driving force control device that can maintain and improve the running stability of the vehicle.

  The present invention estimates first tire force estimation means for estimating a tire force generated on a wheel as a first tire force based on a driver request, and estimates a tire force currently generated on the wheel as a second tire force. Second tire force estimating means, friction circle limit value setting means for setting a friction circle limit value of tire force, and a tire exceeding the friction circle limit value based on the first tire force and the friction circle limit value Tire force exceeding the friction circle limit value based on the second tire force and the friction circle limit value based on the first over tire force estimation means for estimating the force as the first over tire force; Second over-tyre force estimating means for estimating the tire force; driving force setting means for setting a driving force based on the first over-tyre force and the second over-tyre force; Tire chain mounting detection means for detecting vehicle body slip angular velocity estimating means for estimating vehicle slip angular velocity, and correction of the driving force set by the driving force setting means according to the tire chain mounting state and the vehicle slip angular velocity A driving force correction means for setting the amount and correcting the set driving force is provided.

  According to the vehicle driving force control device of the present invention, regardless of whether the tire chain is attached or not, an excessive driving force estimated to occur not only now but also in the future is suppressed, and the tire grip force is appropriately adjusted. It is possible to maintain and improve the running stability of the vehicle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 14 show an embodiment of the present invention, FIG. 1 is a functional block diagram showing the configuration of a driving force control device, FIG. 2 is a flowchart of a driving force control program, and FIG. 3 is a flowchart continuing from FIG. FIG. 4 is an explanatory diagram showing an example of engine torque set by the engine speed and the throttle opening, and FIG. 5 is an explanatory diagram showing an example of the relationship between the accelerator opening and the throttle opening for generating the required engine torque. 6 is a flowchart of an additional yaw moment calculation routine, FIG. 7 is an explanatory diagram of a lateral acceleration saturation coefficient, FIG. 8 is a characteristic map of a vehicle speed sensitivity gain, and FIG. 9 is a value of an additional yaw moment on a high μ road and a low μ road. FIG. 10 is a functional block diagram of the control amount correction unit, FIG. 11 is a flowchart of the control amount correction program, FIG. 12 is a characteristic diagram of the first correction amount, and FIG. 13 is a straightness gain. FIG. 14 is an explanatory diagram of the over-tire force to be suppressed. In this embodiment, a four-wheel drive vehicle with a center differential is taken as an example of the vehicle, and a vehicle in which the longitudinal driving force distribution can be varied from the base torque distribution Rf_cd by the center differential by a differential limiting clutch or the like (fastening torque TLSD). Explained as an example.

In FIG. 1, reference numeral 1 denotes a vehicle driving force control device that is mounted on a vehicle and appropriately suppresses the driving force. The driving force control device 1 includes a throttle opening sensor 11, an engine speed sensor 12, an accelerator. An opening sensor 13, a transmission control unit 14, a lateral acceleration sensor 15, a yaw rate sensor 16, a handle angle sensor 17, a wheel speed sensor 18 for each wheel, a road surface μ estimation device 19, and a tire chain mounting detection device 20 are connected to open the throttle. Degree θth, engine rotation speed Ne, accelerator opening θACC, main transmission gear ratio i, torque converter turbine rotation speed Nt, differential limiting clutch engagement torque TLSD, lateral acceleration (d ² y / dt ² ), yaw rate γ, Handle angle θH, wheel speed ωfl, ωfr, ωrl, ωrr of each wheel (subscript “fl” is the left front wheel, “fr” is the right front wheel, “rl” is the left rear wheel "Rr" denotes a rear-right wheel), the road surface friction coefficient mu, the mounted state of the tire chain is input. The tire chain mounting detection device 20 described above serves as tire chain mounting detection means. For example, it detects fluctuations in the rotational speed of the wheels or detects vibrations of the wheels, suspensions, vehicle bodies, etc. Side and rear wheel side tire chain mounting is determined.

  Based on these input signals, the driving force control device 1 calculates an appropriate driving force in accordance with a driving force control program described later, and outputs it to the engine control unit 2. The engine control unit 2 outputs a control signal to a throttle control unit (not shown) to drive the motor and operate the throttle valve.

  As shown in FIG. 1, the driving force control device 1 includes an engine torque calculating unit 1a, a required engine torque calculating unit 1b, a transmission output torque calculating unit 1c, a total driving force calculating unit 1d, a front / rear ground load calculating unit 1e, and a left wheel load. Ratio calculation unit 1f, each wheel contact load calculation unit 1g, each wheel longitudinal force calculation unit 1h, each wheel required lateral force calculation unit 1i, each wheel lateral force calculation unit 1j, each wheel friction circle limit value calculation unit 1k, each wheel Required tire resultant force calculating unit 1l, each wheel tire resultant force calculating unit 1m, each wheel required overtire resultant force calculating unit 1n, each wheel overtire resultant force calculating unit 1o, overtire force calculating unit 1p, overtorque calculating unit 1q, control amount calculating It is mainly composed of a unit 1r and a control amount correction unit 1s.

  The engine torque calculator 1 a receives the throttle opening θth from the throttle opening sensor 11 and the engine speed Ne from the engine speed sensor 12. Then, a currently set engine torque Teg is obtained by referring to a map (for example, the map shown in FIG. 4) set in advance according to engine characteristics, and is output to the transmission output torque calculation unit 1c. The engine torque Teg may be read from the engine control unit 2 and used.

  The requested engine torque calculator 1 b receives the accelerator opening θACC from the accelerator opening sensor 13. Then, the throttle opening θth is obtained from a preset map (for example, a map of θACC-θth relationship as shown in FIG. 5), and based on the throttle opening θth, the map shown in FIG. 4 is used. The engine torque Teg is obtained, and this engine torque Teg is output as the required engine torque Tdrv to the control amount calculation unit 1r and the control amount correction unit 1s. The required engine torque Tdrv may be obtained from a map corresponding to a preset accelerator opening degree θACC, or may be read from the engine control unit 2 and used.

  The transmission output torque calculation unit 1c receives the engine rotation speed Ne from the engine rotation speed sensor 12, the main transmission gear ratio i from the transmission control unit 14, and the turbine rotation speed Nt of the torque converter, and the engine torque from the engine torque calculation unit 1a. Teg is input.

Then, for example, the transmission output torque Tt is calculated by the following equation (1), and is output to the total driving force calculation unit 1d and the wheel front / rear force calculation unit 1h.
Tt = Teg · t · i (1)
Here, t is a torque ratio of the torque converter, and is obtained by referring to a preset map of the rotational speed ratio e (= Nt / Ne) of the torque converter and the torque ratio of the torque converter. In the control amount correction unit 1s described later, a value obtained by multiplying the torque ratio t of the torque converter and the main transmission gear ratio i is referred to as an instantaneous total gear ratio Grmoment.

  The total driving force calculation unit 1d receives the transmission output torque Tt from the transmission output torque calculation unit 1c.

Then, for example, the total driving force Fx is calculated by the following equation (2), and is output to the front / rear ground load calculation unit 1e and each wheel front / rear force calculation unit 1h.
Fx = Tt · η · if / Rt (2)
Here, η is drive system transmission efficiency, if is the final gear ratio, and Rt is the tire radius.

The front / rear ground load calculation unit 1e receives the total driving force Fx from the total driving force calculation unit 1d. Then, the front wheel ground load Fzf is calculated by the following equation (3) and output to each wheel ground load calculating unit 1g and each wheel longitudinal force calculating unit 1h, and the rear wheel ground load Fzr is calculated by the following equation (4). Calculate and output to each wheel ground load calculation unit 1g.
Fzf = Wf − ((m · (d ² x / dt ² ) · h) / L) (3)
Fzr = W−Fzf (4)
Here, Wf is the front wheel static load, m is the vehicle mass, (d ² x / dt ² ) is the longitudinal acceleration (= Fx / m), h is the height of the center of gravity, L is the wheel base, and W is the vehicle weight (= m G: G is the acceleration of gravity).

Lateral acceleration (d ² y / dt ² ) is input from the lateral acceleration sensor 15 to the left wheel load ratio calculation unit 1 f. Then, the left wheel load ratio WR_l is calculated by the following equation (5), and is output to each wheel ground load calculating unit 1g, each wheel required lateral force calculating unit 1i, and each wheel lateral force calculating unit 1j.
WR — 1 = 0.5 − ((d ² y / dt ² ) / G) · (h / Ltred) (5)
Here, Ltred is the average tread value of the front and rear wheels.

Each wheel ground load calculation unit 1g receives a front wheel ground load Fzf and a rear wheel ground load Fzr from the front and rear ground load calculation unit 1e, and a left wheel load ratio WR_l from the left wheel load ratio calculation unit 1f. Then, the left front wheel ground load Fzf_l, the right front wheel ground load Fzf_r, the left rear wheel ground load Fzr_l, and the right rear wheel ground load Fzr_r are calculated by the following equations (6), (7), (8), and (9), respectively. And output to each wheel friction circle limit value calculation unit 1k.
Fzf_l = Fzf · WR_l (6)
Fzf_r = Fzf · (1−WR_l) (7)
Fzr_l = Fzr · WR_l (8)
Fzr_r = Fzr · (1−WR_l) (9)

  Each wheel longitudinal force calculation unit 1h receives a differential limiting clutch engagement torque TLSD in the center differential from the transmission control unit 14, receives a transmission output torque Tt from the transmission output torque calculation unit 1c, and outputs a total driving force calculation unit 1d. The total driving force Fx is input from the front and the front wheel ground load Fzf is input from the front and rear ground load calculation unit 1e. Then, for example, according to the procedure described later, the left front wheel front / rear force Fxf_l, the right front wheel front / rear force Fxf_r, the left rear wheel front / rear force Fxr_l, and the right rear wheel front / rear force Fxr_r are calculated. It outputs to a wheel tire resultant force calculating part 1m.

  Hereinafter, an example of a procedure for calculating the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right rear wheel longitudinal force Fxr_r will be described.

First, the front wheel load distribution ratio WR_f is calculated by the following equation (10).
WR_f = Fzf / W (10)
Next, the minimum front wheel torque Tfmin and the maximum front wheel torque Tfmax are calculated by the following equations (11) and (12).
Tfmin = Tt · Rf_cd−TLSD (≧ 0) (11)
Tfmax = Tt · Rf_cd + TLSD (≧ 0) (12)

Next, the minimum front wheel longitudinal force Fxfmin and the maximum front wheel longitudinal force Fxfmax are calculated by the following equations (13) and (14).
Fxfmin = Tfmin · η · if / Rt (13)
Fxfmax = Tfmax · η · if / Rt (14)

Then, the state is determined as follows.
When WR_f ≦ Fxfmin / Fx, it is assumed that the differential limiting torque is increased on the rear wheel side, and the determination value I = 1.
When WR_f ≧ Fxfmax / Fx, it is assumed that the differential limiting torque is increased on the front wheel side, and the determination value I = 3.
In cases other than the above, it is determined as normal time, and the determination value I = 2.

Next, according to the determination value I described above, the front wheel longitudinal force Fxf is calculated as follows.
When I = 1 Fxf = Tfmin · η · if / Rt (15)
When I = 2 ... Fxf = Fx.WR_f (16)
When I = 3 Fxf = Fxfmax · η · if / Rt (17)

  Then, the rear wheel longitudinal force Fxr is calculated by the following equation (18) from the front wheel longitudinal force Fxf calculated by the equation (15), (16) or (17).

            Fxr = Fx−Fxf (18)

By using the front wheel longitudinal force Fxf and the rear wheel longitudinal force Fxr, the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right according to the following equations (19) to (22) The rear wheel longitudinal force Fxr_r is calculated.
Fxf_l = Fxf / 2 (19)
Fxf_r = Fxf_l (20)
Fxr_l = Fxr / 2 (21)
Fxr_r = Fxr_l (22)

  Note that the calculation of the front-rear force of each wheel shown in the present embodiment is merely an example, and is appropriately selected according to the drive type / drive mechanism of the vehicle.

In each wheel required lateral force calculation unit 1i, the lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15, the yaw rate γ from the yaw rate sensor 16, the handle angle θH from the handle angle sensor 17 (4 Wheel) The wheel speeds ωfl, ωfr, ωrl, and ωrr of each wheel are input from the wheel speed sensor 18, and the left wheel load ratio WR_l is input from the left wheel load ratio calculation unit 1f.

  Then, the additional yaw moment Mzθ is calculated according to the procedure described later (according to the flowchart shown in FIG. 6). Based on this additional yaw moment, the required front wheel lateral force Fyf_FF is calculated according to the following equation (23). ) To calculate the required rear wheel lateral force Fyr_FF. Based on these required front wheel lateral force Fyf_FF and requested rear wheel lateral force Fyr_FF, the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right by the formulas (25) to (28) The rear wheel required lateral force Fyr_r_FF is calculated and output to each wheel required tire resultant force calculating unit 1l.

Fyf_FF = Mzθ / L (23)
Fyr_FF = (− Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lf) / L (24)
Here, Iz is the yaw moment of inertia of the vehicle, and Lf is the distance between the front axis and the center of gravity.

Fyf_l_FF = Fyf_FF · WR_l (25)
Fyf_r_FF = Fyf_FF · (1-WR_l) (26)
Fyr_l_FF = Fyr_FF · WR_l (27)
Fyr_r_FF = Fyr_FF · (1-WR_l) (28)

Further, as shown in FIG. 6, the additional yaw moment Mzθ is first calculated in step (hereinafter abbreviated as “S”) 201 to calculate the vehicle speed V (for example, V = (ωfl + ωfr + ωrl + ωrr) / 4), and proceeds to S202. The lateral acceleration / steering wheel angle gain Gy is calculated by the following equation (29).
Gy = (1 / (1 + A · V ² )) · (V ² / L) · (1 / n) (29)
Here, A is a stability factor, and n is a steering gear ratio.

Next, in S203, a map set in advance according to the value obtained by multiplying the lateral acceleration / handle angle gain Gy and the handle angle θH (Gy · θH) and the lateral acceleration (d ² y / dt ² ) is referred to. Then, the lateral acceleration saturation coefficient Kμ is calculated. As shown in FIG. 7A, the map for obtaining the lateral acceleration saturation coefficient Kμ is obtained by multiplying the lateral acceleration / handle angle gain Gy by the handle angle θH (Gy · θH) and the lateral acceleration (d ² y / dt ² ), and is set to a smaller value as the lateral acceleration (d ² y / dt ² ) increases when the handle angle θH is equal to or greater than a predetermined value. This lateral acceleration as is a high μ road when Gy · .theta.H large ^(d 2 y / dt ²⁾ is larger, the lateral acceleration ^(d 2 y / dt ²⁾ is less likely to occur in the low μ road It expresses. As a result, the value of the reference lateral acceleration (d ² yr / dt ² ), which will be described later, is large when Gy · θH is large, as shown in FIG. 7B, and the lateral acceleration (d ² y / dt ² ) is large. When the road is considered to be a road, the value is set to a low value so that the correction amount for the additional yaw moment Mzθ is small.

Next, in S204, the lateral acceleration deviation sensitive gain Ky is calculated by the following equation (30).
Ky = Kθ / Gy (30)
Here, Kθ is a steering angle sensitive gain, and is calculated by the following equation (31).
Kθ = (Lf · Kf) / n (31)
Kf is the equivalent cornering power of the front shaft.

That is, according to the above equation (30), the lateral acceleration deviation sensitive gain Ky is set as a guideline (maximum value) in a state where the rudder does not work at all on an extremely low μ road (γ = 0, (d ² y / dt ² ) = 0) and the case where the additional yaw moment Mzθ (steady value) is 0 is considered.

Next, in S205, the reference lateral acceleration (d ² yr / dt ² ) is calculated by the following equation (32).

(D ² yr / dt ² ) = Kμ · Gy · (1 / (1 + Ty · s)) · θH (32)
Here, s is a differential operator, Ty is a first-order lag time constant of lateral acceleration, and this first-order lag time constant Ty is calculated by, for example, the following equation (33), where Kr is the equivalent cornering power of the rear axis. Is done.
Ty = Iz / (L · Kr) (33)

Next, in S206, the lateral acceleration deviation (d ² ye / dt ² ) is calculated by the following equation (34).
(D ² ye / dt ² ) = (d ² y / dt ² ) − (d ² yr / dt ² ) (34)

In step S207, the yaw rate / handle angle gain Gγ is calculated by the following equation (35).
Gγ = (1 / (1 + A · V ² )) · (V / L) · (1 / n) (35)

Next, the process proceeds to S208, and the following equation (36) is used, for example, considering the case where the additional yaw moment Mzθ (steady value) becomes 0 during grip travel ((d ² ye / dt ² ) = 0), The gain Kγ is calculated.

    Kγ = Kθ / Gγ (36)

  In step S209, a vehicle speed sensitive gain Kv is calculated using a preset map. This map is set in order to avoid an unnecessary additional yaw moment Mzθ in a low speed region, for example, as shown in FIG. In FIG. 8, Vc1 is 40 km / h, for example.

In S210, the additional yaw moment Mzθ is calculated by the following equation (37).
Mzθ = Kv · (−Kγ · γ + Ky · (d ² ye / dt ² ) + Kθ · θH) (37)

That is, as shown in the equation (37), the term −Kγ · γ is a yaw moment that is sensitive to the yaw rate γ, the term Kθ · θH is a yaw moment that is sensitive to the handle angle θH, and Ky · (d ² ye / dt The term ² ) is the correction value for the yaw moment. For this reason, as shown in FIG. 9, when the lateral acceleration (d ² y / dt ² ) is operated on a high μ road, the additional yaw moment Mzθ also becomes a large value, and the motion performance is improved. On the other hand, when traveling on a low μ road, the additional yaw moment Mzθ reduces the additional yaw moment Mzθ by the above-described correction value, so that the turning performance does not increase and stable traveling performance can be obtained. It has become.

Each wheel lateral force calculation unit 1j receives a lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15, a yaw rate γ from the yaw rate sensor 16, and a left wheel load ratio WR_l from the left wheel load ratio calculation unit 1f. Then, the front wheel lateral force Fyf_FB is calculated by the following equation (38), and the rear wheel lateral force Fyr_FB is calculated by the following equation (39). Based on these front wheel lateral force Fyf_FB and rear wheel lateral force Fyr_FB, the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, the right rear wheel lateral force Fyr_r_FB Is output to each wheel tire resultant force calculation unit 1m.
Fyf_FB = (Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lr) / L (38)
Fyr_FB = (− Iz · (dγ / dt)
+ M · (d ² y / dt ² ) · Lf) / L (39)
Here, Lr is the distance between the rear axis and the center of gravity.
Fyf_l_FB = Fyf_FB · WR_l (40)
Fyf_r_FB = Fyf_FB · (1-WR_l) (41)
Fyr_l_FB = Fyr_FB · WR_l (42)
Fyr_r_FB = Fyr_FB · (1-WR_l) (43)

  Each wheel friction circle limit value calculation unit 1k receives a road surface friction coefficient μ from the road surface μ estimation device 19, and each wheel ground load calculation unit 1g receives a left front wheel ground load Fzf_l, a right front wheel ground load Fzf_r, and a left rear wheel ground load. Fzr_l and right rear wheel ground load Fzr_r are input.

Then, the left front wheel friction circle limit value μ_Fzfl, the right front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle limit value μ_Fzrr are calculated by the following equations (44) to (47). , Output to each wheel required overtire force calculation unit 1n and each wheel overtire force calculation unit 1o. That is, each wheel friction circle limit value calculation unit 1k is provided as friction circle limit value setting means.
μ_Fzfl = μ · Fzf_l (44)
μ_Fzfr = μ · Fzf_r (45)
μ_Fzrl = μ · Fzr_l (46)
μ_Fzrr = μ · Fzr_r (47)

Each wheel request tire resultant force calculation unit 1l receives the left front wheel front / rear force Fxf_l, right front wheel front / rear force Fxf_r, left rear wheel front / rear force Fxr_l, and right rear wheel front / rear force Fxr_r from each wheel front / rear force calculation unit 1h. The left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right rear wheel required lateral force Fyr_r_FF are input from the lateral force calculation unit 1i. Then, the left front wheel required tire resultant force F_fl_FF, the right front wheel required tire resultant force F_fr_FF, the left rear wheel required tire resultant force F_rl_FF, and the right rear wheel required tire resultant force F_rr_FF are calculated by the following equations (48) to (51), It outputs to the over tire force calculating part 1n. In other words, each wheel required tire resultant force calculating section 11 is provided as a first tire force estimating means.
F_fl_FF = (Fxf_l ² + Fyf_l_FF ² ) ^1/2 (48)
F_fr_FF = (Fxf_r ² + Fyf_r_FF ² ) ^1/2 (49)
F_rl_FF = (Fxr_l ² + Fyr_l_FF ² ) ^1/2 (50)
F_rr_FF = (Fxr_r ² + Fyr_r_FF ² ) ^1/2 (51)

Each wheel tire resultant force calculation unit 1m receives the left front wheel front / rear force Fxf_l, right front wheel front / rear force Fxf_r, left rear wheel front / rear force Fxr_l, and right rear wheel front / rear force Fxr_r from each wheel front / rear force calculation unit 1h. A left front wheel lateral force Fyf_l_FB, a right front wheel lateral force Fyf_r_FB, a left rear wheel lateral force Fyr_l_FB, and a right rear wheel lateral force Fyr_r_FB are input from the calculation unit 1j. Then, the left front wheel tire resultant force F_fl_FB, the right front wheel tire resultant force F_fr_FB, the left rear wheel tire resultant force F_rl_FB, and the right rear wheel tire resultant force F_rr_FB are calculated by the following equations (52) to (55), Output to 1o. That is, each wheel tire resultant force calculation unit 1m is provided as second tire force estimation means.
F_fl_FB = (Fxf_l ² + Fyf_l_FB ² ) ^1/2 (52)
F_fr_FB = (Fxf_r ² + Fyf_r_FB ² ) ^1/2 (53)
F_rl_FB = (Fxr_l ² + Fyr_l_FB ² ) ^1/2 (54)
F_rr_FB = (Fxr_r ² + Fyr_r_FB ² ) ^1/2 (55)

Each wheel required over-tyre force calculation unit 1n receives from each wheel friction circle limit value calculation unit 1k, left front wheel friction circle limit value μ_Fzfl, right front wheel friction circle limit value μ_Fzfr, left rear wheel friction circle limit value μ_Fzrl, right rear wheel friction The circle limit value μ_Fzrr is input, and the left front wheel required tire resultant force F_fl_FF, the right front wheel required tire resultant force F_fr_FF, the left rear wheel required tire resultant force F_rl_FF, and the right rear wheel required tire resultant force F_rr_FF are input from each wheel required tire resultant force calculation unit 1l. . Then, the front left wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, the left rear wheel required overtire force ΔF_rl_FF, and the right rear wheel required overtire force ΔF_rr_FF are calculated by the following equations (56) to (59). And output to the over-tyre force calculator 1p. That is, each wheel required overtire force calculation unit 1n is provided as a first overtire force estimation means.
ΔF_fl_FF = F_fl_FF−μ_Fzfl (56)
ΔF_fr_FF = F_fr_FF−μ_Fzfr (57)
ΔF_rl_FF = F_rl_FF−μ_Fzrl (58)
ΔF_rr_FF = F_rr_FF−μ_Fzrr (59)

Each wheel over-tyre force calculation unit 1o receives the left front wheel friction circle limit value μ_Fzfl, the left front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle from each wheel friction circle limit value calculation unit 1k. The limit value μ_Fzrr is input, and the left front wheel tire combined force F_fl_FB, the right front wheel tire combined force F_fr_FB, the left rear wheel tire combined force F_rl_FB, and the right rear wheel tire combined force F_rr_FB are input from each wheel tire combined force calculation unit 1m. Then, according to the following equations (60) to (63), the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB, and the right rear wheel over-tyre force ΔF_rr_FB are calculated. It outputs to the calculating part 1p. That is, each wheel overtire force calculation unit 1o is provided as a second overtire force estimation means.
ΔF_fl_FB = F_fl_FB−μ_Fzfl (60)
ΔF_fr_FB = F_fr_FB−μ_Fzfr (61)
ΔF_rl_FB = F_rl_FB−μ_Fzrl (62)
ΔF_rr_FB = F_rr_FB−μ_Fzrr (63)

The over-tyre force calculating unit 1p receives the left front wheel required over-tyre force ΔF_fl_FF, the left front wheel required over-tyre force ΔF_fr_FF, the left rear wheel required over-tyre force ΔF_rl_FF, and the right rear wheel required over-tyre force from each wheel required over-tyre force calculating unit 1n. ΔF_rr_FF is input, and the left front wheel overtire force ΔF_fl_FB, the right front wheel overtire force ΔF_fr_FB, the left rear wheel overtire force ΔF_rl_FB, and the right rear wheel overtire force ΔF_rr_FB are input from each wheel overtire force calculation unit 1o. Then, the sum of each wheel required overtire force ΔF_fl_FF, ΔF_fr_FF, ΔF_rl_FF, ΔF_rr_FF and the sum of each wheel overtire force ΔF_fl_FB, ΔF_fr_FB, ΔF_rl_FB, ΔF_rr_FB are compared, and the larger value is set as the overtire force Fover. To do. That is,
Fover = MAX ((ΔF_fl_FF + ΔF_fr_FF + ΔF_rl_FF + ΔF_rr_FF)
, (ΔF_fl_FB + ΔF_fr_FB + ΔF_rl_FB + ΔF_rr_FB)) (64)

The overtorque calculation unit 1q is configured such that the engine rotation speed Ne from the engine rotation speed sensor 12, the main transmission gear ratio i from the transmission control unit 14, the turbine rotation speed Nt of the torque converter, and the overtire force Fover from the overtire force calculation unit 1p. Is entered. Then, the overtorque Tover is calculated by the following equation (65) and output to the control amount calculation unit 1r.
Tover = Fover · Rt / t / i / η / if (65)

The control amount calculator 1r receives the requested engine torque Tdrv from the requested engine torque calculator 1b, and receives the over torque Tover from the overtorque calculator 1q. Then, the control amount Treq is calculated by the following equation (66) and output to the control amount correction unit 1s.
Treq = Tdrv−Tover (66)

  As described above, in this embodiment, the over-tyre force calculating unit 1p, the over-torque calculating unit 1q, and the control amount calculating unit 1r constitute driving force setting means.

The control amount correction unit 1s receives the engine speed Ne from the engine speed sensor 12, the main transmission gear ratio i from the transmission control unit 14, the turbine speed Nt of the torque converter, and the lateral acceleration (d ² y from the lateral acceleration sensor 15). / Dt ² ), the yaw rate γ from the yaw rate sensor 16, the wheel speeds ωfl, ωfr, ωrl, ωrr of each wheel from the four-wheel wheel speed sensor 18, and the tire chain mounting state (tire chain) from the tire chain mounting detection device 20. Non-mounted, tire chain mounted (front wheel side), tire chain mounted (rear wheel side) states), the required engine torque Tdrv is input from the required engine torque calculator 1b, and the controlled variable Treq is input from the controlled variable calculator 1r. The Then, the control amount Treq is corrected in accordance with a control amount correction program described later, and is output to the engine control unit 2. Details of the control amount correction unit 1s will be described below.

  As shown in FIG. 10, the control amount correction unit 1s includes a vehicle speed calculation unit 30a, a vehicle slip angular velocity calculation unit 30b, a first correction amount calculation unit 30c, an instantaneous total gear ratio calculation unit 30d, and a required engine output torque calculation unit 30e. , An ideal longitudinal acceleration calculation unit 30f, an actual longitudinal acceleration calculation unit 30g, a straightness gain setting unit 30h, a second correction amount calculation unit 30i, and a correction control amount calculation unit 30j.

  The vehicle speed calculation unit 30a receives the wheel speeds ωfl, ωfr, ωrl, and ωrr of each wheel from the four-wheel wheel speed sensor 18, and calculates the vehicle speed V (= (ωfl + ωfr + ωrl + ωrr) / 4) by calculating the average of these, for example. Calculate and output to the vehicle slip angular velocity calculation unit 30b and the ideal longitudinal acceleration calculation unit 30f.

The vehicle slip angular velocity calculation unit 30b receives the lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15, the yaw rate γ from the yaw rate sensor 16, and the vehicle speed V from the vehicle speed calculation unit 30a. For example, the vehicle slip angular velocity (dβ / dt) is calculated by the following equation (67) and input to the first correction amount calculation unit 30c. That is, the vehicle slip angular velocity calculation unit 30b is provided as vehicle slip angular velocity estimation means.

(Dβ / dt) = | γ | − | (d ² y / dt ² ) / V | (67)

  The first correction amount calculation unit 30c receives the tire chain mounting state (each state of tire chain not mounted, tire chain mounted (front wheel side), tire chain mounted (rear wheel side)) from the tire chain mounting detection device 20. The vehicle slip angular velocity (dβ / dt) is input from the vehicle slip angular velocity calculation unit 30b. Then, for example, as shown in FIG. 12, a map set in advance is referred to, a torque amount (torque down amount) to be further reduced from the control amount Treq is obtained as a first correction amount ΔTd1, and a corrected control amount calculation is performed. To the unit 30j.

  As shown in FIG. 12, the first correction amount ΔTd1 is set larger as the vehicle slip angular velocity (dβ / dt) increases. Further, the torque reduction amount is set to be larger as the tire chain is attached. In particular, when a tire chain is installed on the front wheel side, it is likely to become a spin and the vehicle tends to become unstable, so the torque down amount is set to be larger than when a tire chain is installed on the rear wheel side. The Depending on the vehicle characteristics, the torque-down characteristic in which the tire chain is mounted on the front wheel side and the torque-down characteristic in which the tire chain is mounted on the rear wheel side may be the same.

  The instantaneous total gear ratio calculation unit 30d receives the engine speed Ne from the engine speed sensor 12, and the main transmission gear ratio i and the turbine speed Nt of the torque converter from the transmission control unit 14. Then, as explained in the transmission output torque calculation unit 1c described above, the instantaneous total gear ratio Grmoment (= t · i) is calculated by multiplying the torque ratio t of the torque converter and the main transmission gear ratio i, and the required engine It outputs to the output torque calculating part 30e and the 2nd correction amount calculating part 30i.

  The required engine output torque calculator 30e receives the required engine torque Tdrv from the required engine torque calculator 1b and the instantaneous total gear ratio Grmoment from the instantaneous total gear ratio calculator 30d. Then, the required engine output torque Ttmoutreq (= Tdrv · Grmoment) is obtained by multiplying them and output to the ideal longitudinal acceleration calculation unit 30f.

The ideal longitudinal acceleration calculation unit 30f receives the vehicle speed V from the vehicle speed calculation unit 30a and the request engine output torque Ttmoutreq from the request engine output torque calculation unit 30e. Then, for example, the ideal longitudinal acceleration (ideal longitudinal acceleration) Axideal is calculated by the following equation (68), and is output to the second correction amount calculation unit 30i.
Axideal = (Ttmoutreq · if−Tinertia) / Rt / m (68)
Here, Tinertia is an inertia torque that takes into account the rotational inertia necessary for the wheel to accelerate and rotate, and is calculated by, for example, the following equation (69).
Tinertia = (dV / dt) · (2 · π · Jω) / (3.6 · 2 · π · Rt)
... (69)
Here, Jω is the rotational moment of inertia of the four wheels.

The actual longitudinal acceleration calculation unit 30g receives the vehicle speed V from the vehicle speed calculation unit 30a, calculates an actual longitudinal acceleration (actual longitudinal acceleration) Axwheel by, for example, the following equation (70), and the second correction amount calculation unit Output to 30i.
Axwheel = (dV / dt) /3.6 (70)

The straightness gain setting unit 30h receives the lateral acceleration (d ² y / dt ² ) from the lateral acceleration sensor 15 and refers to a preset characteristic map shown in FIG. Gstr is set and output to the second correction amount calculator 30i. That is, in the characteristic shown in FIG. 13, the straightness gain Gstr is a characteristic that becomes 0 when the lateral acceleration (d ² y / dt ² ) is generated, and this correction is only in the straight direction. It is intended to correct the driving force for.

The second correction amount calculation unit 30i includes the instantaneous total gear ratio Grmoment from the instantaneous total gear ratio calculation unit 30d, the ideal longitudinal acceleration Axideal from the ideal longitudinal acceleration calculation unit 30f, and the actual longitudinal acceleration Axwheel from the actual longitudinal acceleration calculation unit 30g. The straightness gain Gstr is input from the straightness gain setting unit 30h. Then, a torque amount (torque down amount) to be further reduced from the control amount Treq to suppress wheel slip is obtained as a second correction amount ΔTd2 by the following equation (71), and output to the correction control amount calculation unit 30j. To do.
ΔTd2 = (Axwheel−Axideal) · m · Rt / if / Grmoment · Gstr
... (71)
The lower limit value of the second correction amount ΔTd2 is set to 0. Thus, the 2nd correction amount calculating part 30i has a function as a slip state detection means.

The correction control amount calculation unit 30j receives the control amount Treq from the control amount calculation unit 1r, receives the first correction amount ΔTd1 from the first correction amount calculation unit 30c, and receives the first correction amount ΔTd1 from the second correction amount calculation unit 30i. A correction amount ΔTd2 of 2 is input. Then, the first correction amount ΔTd1 and the second correction amount ΔTd2 are compared, the larger torque reduction amount is determined as the final correction amount, and the control amount Treq is corrected by subtracting it from the control amount Treq. And output to the engine control unit 2. That is,
Treq = Treq−MAX (ΔTd1, ΔTd2) (72)
Thus, the correction control amount calculation unit 30j is provided as a driving force correction unit.

  Then, as shown in the flowchart of FIG. 11, the control amount correction program executed by the control amount correction unit 1s first calculates the vehicle speed V by the vehicle speed calculation unit 30a in S301, and proceeds to S302 to calculate the vehicle slip angular velocity. The unit 30b calculates the vehicle slip angular velocity (dβ / dt) by the above-described equation (67).

  Next, the process proceeds to S303, in which the first correction amount calculation unit 30c refers to a map (FIG. 12) set in advance, and the tire chain is mounted (tire chain not mounted, tire chain mounted (front wheel side)), Based on the tire chain mounting (rear wheel side state) and the vehicle body slip angular velocity (dβ / dt), a torque amount (torque down amount) to be further reduced from the control amount Treq is obtained as a first correction amount ΔTd1. .

  Next, the process proceeds to S304, where the instantaneous total gear ratio calculation unit 30d calculates the instantaneous total gear ratio Grmoment, and the process proceeds to S305, where the required engine output torque calculation unit 30e calculates the required engine output torque Ttmoutreq.

  Next, the process proceeds to S306, where the ideal longitudinal acceleration calculation unit 30f calculates the ideal longitudinal acceleration Axideal according to the above equation (68), and the process proceeds to S307, where the actual longitudinal acceleration calculation unit 30g uses the above equation (70). The actual longitudinal acceleration Axwheel is calculated, the process proceeds to S308, and a straightness gain Gstr is set with reference to a characteristic map as shown in FIG. 13 set in advance by the straightness gain setting unit 30h.

  Next, the process proceeds to S309, where the second correction amount calculation unit 30i sets the torque amount (torque down amount) to be further reduced from the control amount Treq to suppress wheel slip by the above-described equation (71). Is obtained as a correction amount ΔTd2.

  In S310, the control amount Treq from the control amount calculation unit 1r is corrected and output to the engine control unit 2 by the above equation (72), and the program exits.

  As described above, the control amount correction unit 1s uses the control amount Treq from the control amount calculation unit 1r as the tire chain mounted state (tire chain not mounted, tire chain mounted (front wheel side), tire chain mounted (rear wheel side). 2) obtained for suppressing wheel slip from the first correction amount ΔTd1 obtained based on the vehicle body slip angular velocity (dβ / dt), the ideal longitudinal acceleration Axideal, and the actual longitudinal acceleration Axwheel. The correction amount ΔTd2 is compared, and the larger correction amount is subtracted for correction. For this reason, the slip state of the wheel is reliably suppressed, and even when the tire chain is mounted, the appropriate driving force is appropriately suppressed in accordance with that, and it is estimated that it will occur not only now but also in the future. Therefore, it is possible to improve the running stability of the vehicle by suppressing the excessive driving force and maintaining the tire grip force appropriately.

  In the present embodiment, the control amount Treq is corrected by comparing the first correction amount ΔTd1 and the second correction amount ΔTd2 and subtracting the larger correction amount. However, depending on the vehicle characteristics, the correction may be always performed by subtracting the first correction amount ΔTd1 without obtaining the two correction amounts.

Next, the driving force control program executed by the above-described driving force control apparatus 1 will be described with reference to the flowcharts of FIGS.
First, in S101, necessary parameters, that is, throttle opening θth, engine rotation speed Ne, accelerator opening θACC, main transmission gear ratio i, torque converter turbine rotation speed Nt, differential limiting clutch engagement torque TLSD, lateral acceleration ( d ² y / dt ² ), yaw rate γ, steering wheel angle θH, wheel speeds ωfl, ωfr, ωrl, ωrr and road surface friction coefficient μ of each wheel are read.

  Next, in S102, the engine torque calculation unit 1a refers to a map (for example, the map shown in FIG. 4) set in advance according to the engine characteristics to obtain the currently generated engine torque Teg.

  Next, the process proceeds to S103, where the requested engine torque calculation unit 1b obtains the throttle opening θth from a preset map (for example, the map of θACC-θth relationship as shown in FIG. 5), and this throttle opening Based on θth, the engine torque Teg is obtained from the map shown in FIG.

  Next, the process proceeds to S104, and the transmission output torque Tt is calculated by the transmission output torque calculation unit 1c by the above-described equation (1).

  Next, proceeding to S105, the total driving force calculation unit 1d calculates the total driving force Fx by the above-described equation (2).

  Next, the process proceeds to S106, where the front / rear ground load calculation unit 1e calculates the front wheel ground load Fzf by the above-described equation (3), and calculates the rear wheel ground load Fzr by the above-described equation (4).

  Next, the process proceeds to S107, and the left wheel load ratio calculation unit 1f calculates the left wheel load ratio WR_l by the above-described equation (5).

  Next, the process proceeds to S108, and each wheel ground load calculation unit 1g uses the above-described formulas (6), (7), (8), and (9) to calculate the left front wheel ground load Fzf_l, the right front wheel ground load Fzf_r, and the left rear, respectively. The wheel contact load Fzr_l and the right rear wheel contact load Fzr_r are calculated.

  Next, the process proceeds to S109, and each wheel longitudinal force calculation unit 1h calculates the left front wheel longitudinal force Fxf_l, the right front wheel longitudinal force Fxf_r, the left rear wheel longitudinal force Fxr_l, and the right rear wheel according to the aforementioned equations (19) to (22). The longitudinal force Fxr_r is calculated.

  Next, the process proceeds to S110, and each wheel required lateral force calculation unit 1i calculates the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right according to the above-described equations (25) to (28). The rear wheel required lateral force Fyr_r_FF is calculated.

  Next, proceeding to S111, each wheel lateral force calculation unit 1j calculates the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, and the right rear wheel according to the aforementioned equations (40) to (43). The lateral force Fyr_r_FB is calculated.

  Next, the process proceeds to S112, and each wheel friction circle limit value calculation unit 1k calculates the left front wheel friction circle limit value μ_Fzfl, the right front wheel friction circle limit value μ_Fzfr, and the left rear wheel friction circle by the above-described equations (44) to (47). The limit value μ_Fzrl and the right rear wheel friction circle limit value μ_Fzrr are calculated.

  Next, the process proceeds to S113, and each wheel required tire resultant force calculation unit 1l calculates the left front wheel required tire resultant force F_fl_FF, the right front wheel required tire resultant force F_fr_FF, and the left rear wheel required tire resultant force F_rl_FF by the above-described equations (48) to (51). The right rear wheel required tire resultant force F_rr_FF is calculated.

  Next, the process proceeds to S114, and each wheel tire resultant force calculation unit 1m calculates the left front wheel tire resultant force F_fl_FB, the right front wheel tire resultant force F_fr_FB, the left rear wheel tire resultant force F_rl_FB, and the right rear wheel tire according to the above formulas (52) to (55). The resultant force F_rr_FB is calculated.

  Next, the process proceeds to S115, where each wheel required overtire force calculation unit 1n calculates the left front wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, and the left rear wheel required according to the expressions (56) to (59) described above. The overtire force ΔF_rl_FF and the right rear wheel required overtire force ΔF_rr_FF are calculated.

  Next, the process proceeds to S116, and each wheel over-tyre force calculation unit 1o calculates the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB by the above-described equations (60) to (63). The right rear wheel over-tyre force ΔF_rr_FB is calculated.

  Next, the process proceeds to S117, and the overtire force calculation unit 1p calculates the overtire force Fover by the above-described equation (64).

  Next, the process proceeds to S118, where the overtorque calculation unit 1q calculates the overtorque Tover using the above-described equation (65), and the process proceeds to S119, where the control amount calculation unit 1r calculates the control amount according to the above-described equation (66). Calculate Treq.

  Then, the process proceeds to S120, and the control amount correction unit 1s determines that the control amount Treq is the same as described above, that is, the tire chain mounted state (tire chain not mounted, tire chain mounted (front wheel side), tire chain mounted (rear wheel side). )) And the first correction amount ΔTd1 obtained based on the vehicle slip angular velocity (dβ / dt), the ideal longitudinal acceleration Axideal, and the actual longitudinal acceleration Axwheel. 2 is compared with the correction amount ΔTd2 of 2 and corrected by subtracting the larger correction amount (Equation (72)) and output to the engine control unit 2 to exit the program.

  As described above, according to the embodiment of the present invention, the torque value at which the tire force generated on the wheel based on the driver request exceeds the friction circle limit value, and the tire force currently generated on the wheel from the friction circle limit value. The torque value to be exceeded is compared, and the larger value is subtracted from the driving force required by the driver. For this reason, not only the present but also the future excessive torque state is properly corrected, the spin and plow are properly controlled, and the tire grip force is properly maintained to maintain the vehicle running stability. It is possible to improve.

  In addition, the value to be corrected by subtracting the driving force required by the driver is a torque value that causes the tire force to exceed the friction circle limit value, so the driving force in the front-rear direction is not suddenly suppressed, and the driver Therefore, there is no unnatural feeling or dissatisfaction such as insufficient acceleration (that is, the driving force is suppressed by Fxa in FIG. 14).

  In addition, the driving force in the front-rear direction may be surely suppressed and the tire grip force may be maintained (that is, the driving force may be suppressed by Fxb in FIG. 14). The control in this case can be realized by adding a signal line indicated by a broken line in FIG. 1 and changing the calculation in each wheel required overtire force calculation unit 1n and each wheel overtire force calculation unit 1o as follows.

  Each wheel required over-tyre force calculation unit 1n receives from each wheel friction circle limit value calculation unit 1k, left front wheel friction circle limit value μ_Fzfl, right front wheel friction circle limit value μ_Fzfr, left rear wheel friction circle limit value μ_Fzrl, right rear wheel friction The circle limit value μ_Fzrr is input, the left front wheel required lateral force Fyf_l_FF, the right front wheel required lateral force Fyf_r_FF, the left rear wheel required lateral force Fyr_l_FF, and the right rear wheel required lateral force Fyr_r_FF are input from each wheel required lateral force calculation unit 1i. A left front wheel longitudinal force Fxf_l, a right front wheel longitudinal force Fxf_r, a left rear wheel longitudinal force Fxr_l, and a right rear wheel longitudinal force Fxr_r are input from each wheel longitudinal force calculation unit 1h.

Then, the left front wheel required overtire force ΔF_fl_FF, the right front wheel required overtire force ΔF_fr_FF, the left rear wheel required overtire force ΔF_rl_FF, and the right rear wheel required overtire force ΔF_rr_FF are calculated by the following equations (73) to (76). And output to the over-tyre force calculator 1p.
ΔF_fl_FF = Fxf_l− (μ_Fzfl ² −Fyf_l_FF ² ) ^1/2 (73)
ΔF_fr_FF = Fxf_r− (μ_Fzfr ² −Fyf_r_FF ² ) ^1/2 (74)
ΔF_rl_FF = Fxr_l− (μ_Fzrl ² −Fyr_l_FF ² ) ^1/2 (75)
ΔF_rr_FF = Fxr_r− (μ_Fzrr ² −Fyr_r_FF ² ) ^1/2 (76)

  Each wheel over-tyre force calculation unit 1o receives the left front wheel friction circle limit value μ_Fzfl, the left front wheel friction circle limit value μ_Fzfr, the left rear wheel friction circle limit value μ_Fzrl, and the right rear wheel friction circle from each wheel friction circle limit value calculation unit 1k. The limit value μ_Fzrr is input, and the left front wheel lateral force Fyf_l_FB, the right front wheel lateral force Fyf_r_FB, the left rear wheel lateral force Fyr_l_FB, and the right rear wheel lateral force Fyr_r_FB are input from each wheel lateral force calculating unit 1j. From 1h, a left front wheel longitudinal force Fxf_l, a right front wheel longitudinal force Fxf_r, a left rear wheel longitudinal force Fxr_l, and a right rear wheel longitudinal force Fxr_r are input.

Then, by calculating the left front wheel over-tyre force ΔF_fl_FB, the right front wheel over-tyre force ΔF_fr_FB, the left rear wheel over-tyre force ΔF_rl_FB, and the right rear wheel over-tyre force ΔF_rr_FB according to the following equations (77) to (80), It outputs to the calculating part 1p.
ΔF_fl_FB = Fxf_l− (μ_Fzfl ² −Fyf_l_FB ² ) ^1/2 (77)
ΔF_fr_FB = Fxf_r− (μ_Fzfr ² −Fyf_r_FB ² ) ^1/2 (78)
ΔF_rl_FB = Fxr_l− (μ_Fzrl ² −Fyr_l_FB ² ) ^1/2 (79)
ΔF_rr_FB = Fxr_r− (μ_Fzrr ² −Fyr_r_FB ² ) ^1/2 (80)

Functional block diagram showing the configuration of the driving force control device Driving force control program flowchart Flowchart continuing from FIG. Explanatory drawing showing an example of engine torque set by engine speed and throttle opening Explanatory drawing which shows an example of the relationship between the accelerator opening and throttle opening for generating required engine torque Flow chart of additional yaw moment calculation routine Illustration of lateral acceleration saturation coefficient Characteristic map of vehicle speed sensitive gain Explanatory diagram of the difference in the value of the additional yaw moment on the high and low μ roads Functional block diagram of control amount correction unit Flow chart of control amount correction program Characteristics diagram of the first correction amount Linearity gain characteristic chart Illustration of over-tyre force to be suppressed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Driving force control apparatus 1a Engine torque calculating part 1b Required engine torque calculating part 1c Transmission output torque calculating part 1d Total driving force calculating part 1e Front and rear ground load calculating part 1f Left wheel load ratio calculating part 1g Each wheel ground load calculating part 1h Each wheel Longitudinal force calculation unit 1i Each wheel required lateral force calculation unit 1j Each wheel lateral force calculation unit 1k Each wheel friction circle limit value calculation unit (friction circle limit value setting means)
1l Each wheel required tire resultant force calculation section (first tire force estimating means)
1m Each wheel tire resultant force calculation section (second tire force estimating means)
1n Each wheel request overtire resultant force calculation section (first overtire force estimation means)
1o Each wheel over-tire resultant force calculation unit (second over-tyre force estimating means)
1p Over-tyre force calculator (driving force setting means)
1q overtorque calculation unit (driving force setting means)
1r Control amount calculation unit (driving force setting means)
1 s Control amount correction unit 2 Engine control unit 20 Tire chain mounting detection device (tire chain mounting detection means)
30a Vehicle speed calculation unit 30b Vehicle slip angular velocity calculation unit (vehicle slip angular velocity estimation means)
30c First correction amount calculation unit 30d Instantaneous total gear ratio calculation unit 30e Required engine output torque calculation unit 30f Ideal longitudinal acceleration calculation unit 30g Actual longitudinal acceleration calculation unit 30h Straightness gain setting unit 30i Second correction amount calculation unit (slip State detection means)
30j Correction control amount calculation unit (driving force correction means)

Claims (5)

First tire force estimating means for estimating a tire force generated on a wheel based on a driver request as a first tire force;
Second tire force estimating means for estimating a tire force currently generated on the wheel as a second tire force;
Friction circle limit value setting means for setting a friction circle limit value of tire force;
First over tire force estimating means for estimating a tire force exceeding the friction circle limit value as a first over tire force based on the first tire force and the friction circle limit value;
Second over tire force estimating means for estimating a tire force exceeding the friction circle limit value as a second over tire force based on the second tire force and the friction circle limit value;
Driving force setting means for setting a driving force based on the first overtire force and the second overtire force;
Tire chain mounting detection means for detecting tire chain mounting;
Vehicle slip angular velocity estimation means for estimating vehicle slip angular velocity;
A driving force correction means for setting a correction amount of the driving force set by the driving force setting means in accordance with the mounting state of the tire chain and the vehicle body slip angular velocity, and correcting the set driving force;
A driving force control apparatus for a vehicle, comprising: First tire force estimating means for estimating a tire force generated on a wheel based on a driver request as a first tire force;
Second tire force estimating means for estimating a tire force currently generated on the wheel as a second tire force;
Friction circle limit value setting means for setting a friction circle limit value of tire force;
First over tire force estimating means for estimating a tire force exceeding the friction circle limit value as a first over tire force based on the first tire force and the friction circle limit value;
Second over tire force estimating means for estimating a tire force exceeding the friction circle limit value as a second over tire force based on the second tire force and the friction circle limit value;
Driving force setting means for setting a driving force based on the first overtire force and the second overtire force;
Tire chain mounting detection means for detecting tire chain mounting;
Vehicle slip angular velocity estimation means for estimating vehicle slip angular velocity;
Slip state detecting means for detecting the slip state of the wheel from the ideal longitudinal acceleration and the actual longitudinal acceleration;
Driving force correction means for setting the driving force correction amount set by the driving force setting means in accordance with the tire chain mounting state, the vehicle slip angular velocity, and the wheel slip state, and correcting the set driving force. When,
A driving force control apparatus for a vehicle, comprising:   The driving force correcting means calculates a first correction amount based on the tire chain mounting state and the vehicle slip angular velocity, calculates a second correction amount based on the wheel slip state, and calculates the first correction amount. 3. The vehicle driving force control apparatus according to claim 2, wherein correction is performed by subtracting the larger correction amount of the correction amount and the second correction amount from the set driving force.   The driving force setting means compares the first overtire force and the second overtire force, and sets the driving force by subtracting the larger overtire force from the driving force requested by the driver. The vehicle driving force control device according to any one of claims 1 to 3, wherein the vehicle driving force control device is a vehicle driving force control device.   The driving force setting means compares the first over tire force and the second over tire force, and subtracts the longitudinal component of the larger over tire force from the driving force requested by the driver. The driving force control device for a vehicle according to any one of claims 1 to 3, wherein a driving force is set.

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