JP2006291863A - Vehicle driving force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct target driving force so as to suppress a change of a vehicle speed when a vehicle passes through such a level difference that causes its travelling resistance to be instantaneously increased/reduced. <P>SOLUTION: This vehicle driving force control device detects an amount of a change in a height of a road surface due to the level difference existing in front of the vehicle in a moving direction and corrects target driving force calculated in accordance with an amount of an accelerator footed by a driver, corresponding to an amount of the change in the height of the road surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a driving force control apparatus for a vehicle.

  A technique for controlling the driving force of a vehicle by using an electronically controlled throttle valve to control the opening of the throttle valve based on the vehicle speed and the accelerator operation amount is known. However, even if the vehicle speed and the accelerator opening are constant, the driving force required to generate the desired acceleration differs if the road gradient during traveling is different. For example, on an uphill, the vehicle decelerates with the accelerator opening remaining constant. .

Therefore, the throttle valve opening is controlled to achieve the target acceleration / deceleration calculated based on the accelerator opening, and if the target acceleration / deceleration does not match the actual acceleration / deceleration calculated from the vehicle speed, the throttle valve opening Japanese Patent Application Laid-Open No. H10-228667 describes a technique for obtaining a constant acceleration / deceleration regardless of changes in road surface gradient and the like by correcting the above.
JP 2000-205015 A

  However, in the above conventional technique, when the vehicle running resistance instantaneously increases or decreases and the vehicle speed changes, such as when passing through a step where the road surface height changes suddenly, the changed vehicle speed is restored after passing. Thus, since the throttle valve is corrected, the acceleration / deceleration is greater than the acceleration / deceleration required by the driver, which may cause the driver to feel uncomfortable.

  Further, when the driver changes the accelerator depression amount in order to return the vehicle speed when passing through the step, there is a possibility that the acceleration / deceleration is larger than the acceleration / deceleration required by the driver.

  The present invention has been made paying attention to such a conventional problem, and the target driving force is controlled so as to suppress the change in the vehicle speed when passing through a step where the running resistance of the vehicle instantaneously increases or decreases. It aims at correcting.

  The vehicle driving force control device of the present invention detects the target driving force of the vehicle and the amount of change in the height of the road surface due to the step in front of the traveling direction of the vehicle. The target driving force of the vehicle is corrected so as to compensate for the increase / decrease in running resistance.

  According to the present invention, since the target driving force of the vehicle is corrected so as to compensate for the increase / decrease of the running resistance due to the step that the vehicle passes according to the amount of change in the height of the road surface, the change in the vehicle speed is suppressed when the step passes. This can prevent the driver from feeling uncomfortable.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 2 is a configuration diagram showing a vehicle driving force control apparatus according to this embodiment. The engine 102 generates a driving force of the vehicle 100 and is transmitted to the driving wheels 105 via the continuously variable transmission 103 and the final gear 104. The throttle actuator 8 controls the driving force of the engine 102 by controlling the opening degree of the throttle valve of the engine 102. The throttle actuator 8 is controlled by the engine ECU 7 based on the engine torque command value cTE transmitted from the driving force control ECU 10.

  The continuously variable transmission 103 continuously changes the rotational speed of the engine 102 and outputs it. The continuously variable transmission 103 is controlled by the transmission ECU 6 based on the transmission ratio command value cRATIO transmitted from the driving force control ECU 10.

  The control start switch 1 detects whether or not the driving force control of the vehicle 100 is executed. The switch is turned on when driving force control is executed, and turned off when driving force control is stopped. The brake switch 2 detects whether or not the driver is stepping on the brake. The switch is on when the driver is stepping on the brake, and is off when the driver is not stepping on the brake. The ultrasonic sensor 3 detects the curb 101 in front of the vehicle by analyzing the reflected wave of the ultrasonic wave emitted from the ultrasonic generator attached to the front of the vehicle 100 and the like, and the height of the road surface by the curb 101. The amount of change is detected. When the road surface is raised by the curbstone 101, the height of the curbstone 101 is detected. When the road surface is lowered by the curbstone 101, the amount of descent from the running road surface is detected. The accelerator operation amount sensor 4 detects the amount of depression of the accelerator pedal by the driver. The vehicle speed sensor 5 detects the actual vehicle speed aVSP of the vehicle 100 based on the rotational speed of the tire. The transmission ECU 6 detects the actual gear ratio aRATIO of the continuously variable transmission 103.

  The driving force control ECU 10 calculates the engine torque command value cTE and the gear ratio command value cRATIO based on the control start switch signal, the brake switch signal, the curb height Curb_h, the accelerator depression amount APO, the vehicle speed aVSP, and the actual gear ratio aRATIO, respectively. It transmits to ECU7 and transmission ECU6.

  FIG. 2 is a block diagram showing a vehicle driving force control apparatus according to this embodiment. The driving force control ECU 10 includes a microcomputer and other peripheral components, and is based on signals received from the control start switch 1, the brake switch 2, the ultrasonic sensor 3, the accelerator operation amount sensor 4, the vehicle speed sensor 5, and the transmission ECU 6. An engine torque command value cTE and a gear ratio command value cRATIO are transmitted to the engine ECU 7 and the transmission ECU 6, respectively.

  The engine ECU 7 calculates a throttle opening based on the engine torque command value cTE transmitted from the driving force control ECU 10 and transmits a throttle opening signal to the throttle actuator 8. The throttle actuator 8 controls the opening of the throttle valve of the engine 102 according to the throttle valve opening signal. The transmission ECU 6 controls the gear ratio of the continuously variable transmission 103 based on the gear ratio command value cRATIO transmitted from the driving force control ECU 10.

  The driving force control apparatus for the vehicle 100 according to the present embodiment is configured as described above, and the driving force control ECU 10 controls the driving force of the vehicle 100 by controlling the opening of the throttle valve and the gear ratio of the continuously variable transmission 103. And suppress changes in vehicle speed.

  Next, control performed by the driving force control ECU 10 will be described. In addition, this control is repeatedly performed every predetermined time (for example, 10 ms). In this control, the engine torque command value cTE and the gear ratio command value cRATIO are calculated based on the vehicle speed, the accelerator depression amount APO, and the height of the curb 101, and based on these, the throttle valve opening and the continuously variable transmission shift are calculated. The ratio is to be controlled.

  The control start determination unit 20 determines whether to start driving force control based on the control start switch signal and the brake switch signal, and outputs a control execution flag fSTART. The control execution flag fSTART is set by the control shown in the flowchart of FIG.

  That is, in step S1, it is determined whether or not the control start switch 1 is on. If it is on, the process proceeds to step S2. In step S2, it is determined whether or not the brake switch 2 is on. If it is off, the process proceeds to step S3. In step S3, the control execution flag fSTART is set to 1 and the process is terminated.

  On the other hand, if it is determined in step S1 that the control start switch 1 is off or if it is determined in step S2 that the brake switch 2 is on, the process proceeds to step S4 and the control execution flag fSTART is set to 0. To finish the process. Here, when the brake switch 2 is on, that is, when the driver is stepping on the brake, the vehicle speed cannot be controlled even if the throttle valve opening and the gear ratio are controlled, so the control execution flag fSTART is set to 0. Stop control.

  Returning to FIG. 2, the curb detection unit 30 outputs curb detection flags f_curb_up and f_curb_down based on the travel resistance estimation value dv_Est output from the travel resistance estimation unit 60 described later. Here, the curb detection flag f_curb_up is 1 when it is detected that the curbstone 101 has entered the rising portion, and the curb detection flag f_curb_down is 1 when it has been detected that the curbstone 101 has entered the descending portion. The curb detection flags f_curb_up and f_curb_down are set by the control shown in the flowchart of FIG.

  That is, in step 11, the latest estimated running resistance value dv_Est (n) is read. In step S12, the travel resistance estimated value change amount dv_Est is calculated by subtracting the travel resistance estimated value dv_Est (n-1) at the previous processing from the latest travel resistance estimated value dv_Est (n). In step S13, it is determined whether or not the change amount Δdv_Est is greater than a predetermined positive value D_UP. If it is larger than the predetermined value D_UP, the process proceeds to step S14, and it is determined whether or not the value obtained by subtracting the average value dv_Est_Ave of the estimated running resistance value from the latest estimated running resistance value dv_Est (n) is larger than the positive predetermined value Dp. If it is larger than the predetermined value Dp, the process proceeds to step S15, and if it is less than the predetermined value Dp, the process proceeds to step S16. In step S15, it is determined that the vehicle has entered the rising portion of the curb 101, the curb detection flag f_curb_up is set to 1, and the process proceeds to step S23. In step S16, it is determined that the curb 101 has passed through the descending portion, the curb detection flag f_curb_down is set to 0, and the process proceeds to step S23.

  On the other hand, when it is determined in step S13 that the travel resistance estimated value change Δdv_Est is equal to or smaller than the predetermined value D_UP, the process proceeds to step S17, and it is determined whether or not the travel resistance estimated value change Δdv_Est is smaller than the negative predetermined value D_DOWN. . If it is determined that the value is smaller than the predetermined value D_DOWN, the process proceeds to step S18, and it is determined whether or not the value obtained by subtracting the average value dv_Est_Ave of the running resistance estimated value from the latest running resistance estimated value dv_Est (n) is smaller than the negative predetermined value Dm. judge. If it is determined that the value is smaller than the predetermined value Dm, the process proceeds to step S19. In step S19, it is determined that the vehicle has entered the descending portion of the curb 101, the curb detection flag f_curb_down is set to 1, and the process proceeds to step S23. In step S20, it is determined that the ascending portion of the curb 101 has passed, the curb detection flag f_curb_up is set to 0, and the process proceeds to step S23.

  On the other hand, if it is determined in step S17 that the estimated travel resistance change amount Δdv_Est is greater than or equal to the predetermined value D_DOWN, the process proceeds to step S21, where it is determined whether the curb detection flag f_curb_up is 0 and f_curb_down is 0. If it is determined that the curb detection flags f_curb_up and f_curb_down are both 0, the process proceeds to step S22, and if it is determined that both are 0, the process proceeds to step S23. In step S22, an average value dv_Est_Ave of the estimated running resistance value is calculated, and the process proceeds to step S23.

  In step S23, the previous running resistance estimated value dv_Est (n-1) is updated to the latest running resistance estimated value dv_Est (n) read in step S21, and the process is terminated.

  Returning to FIG. 2, the movement distance calculation unit 40 outputs the movement distances dist_up and dist_down based on the vehicle speed aVSP and the curb detection flags f_curb_up and f_curb_down. The moving distance dist_up represents the moving distance after entering the rising part of the curb 101, and the moving distance dist_down represents the moving distance after entering the descending part of the curb 101. The movement distances dist_up and dist_down are calculated by the control shown in the block diagram of FIG.

  That is, in the integration processing unit 41, when the curb detection flag f_curb_up becomes 1, the integral term is initialized to 0, and the moving distance dist_up is calculated by integrating the vehicle speed aVSP. Here, s is a Laplace operator.

  The integration processing unit 42 initializes the integral term to 0 when the curb detection flag f_curb_down becomes 1, and integrates the vehicle speed aVSP to calculate the travel distance dist_down.

  The control of the curb detection unit 30 and the movement distance calculation unit 40 will be described in detail later with reference to a time chart.

  Returning to FIG. 2, the driving force control unit 50 determines the driving torque command value cTDR based on the accelerator depression amount APO, the vehicle speed aVSP, the control execution flag fSTART, the curb detection flag f_curb_up, f_curb_down, the moving distance dist_up, dist_down, and the curb height Curb_h. Is calculated. The drive torque command value cTDR is calculated by the control shown in the block diagram of FIG.

  That is, the target drive torque map 51 calculates the target drive torque tTDR based on the accelerator depression amount APO and the vehicle speed aVSP with reference to the map of FIG. 7 showing the relationship between the vehicle speed aVSP, the target drive torque tTDR, and the accelerator depression amount APO. To do. Here, as shown in FIG. 7, the target drive torque tTDR increases as the accelerator depression amount APO increases, and decreases as the vehicle speed aVSP increases because the transmission gear ratio decreases.

The engine model 52, the running resistance map 53, the acceleration converting unit 54, the target acceleration input limiting unit 55, and the vehicle speed converting unit 56 constitute a reference model G _R (s), and include a target driving torque tTDR, a vehicle speed aVSP, a target acceleration tACC, and a curb. The target vehicle speed tVSP is calculated based on the detection flags f_curb_up, f_curb_down, accelerator depression amount APO, movement distance dist_up, and dist_down.

The behavior of the power train of the vehicle 100 can be expressed by a simple nonlinear model G _P (s) shown in FIG. 8 by modeling the driving torque command value cTDR as an operation amount and the vehicle speed aVSP as a control amount. Since FIG. 8 defines the characteristics of the vehicle 100 traveling on a flat road, the traveling resistance is the rolling resistance and the air resistance of the vehicle 100. Here, L represents a dead time. However, the characteristics to be controlled include the dead time due to the delay of the power train system, and the dead time L varies depending on the actuator and engine used.

Returning to FIG. 6, the engine model 52 is constituted by dead time processing in which the first-order delay of the time constant τ _Em and the same dead time L as the control target are set. The first order delay of the time constant is expressed by the following equation (1).

G _re (s) = 1 / (τ _Em · s + 1) (1)
Here, s is a Laplace operator.

  The travel resistance map 53 outputs travel resistance based on the input vehicle speed aVSP. The running resistance is the sum of rolling resistance and air resistance of the vehicle 100.

  The acceleration converter 54 calculates the target acceleration tACC by dividing the value obtained by subtracting the running resistance from the target driving torque tTDR by the mass M of the vehicle 100 and the effective radius Rt of the tire.

  As shown in the block diagram of FIG. 9, the target acceleration input restriction unit 55 includes an accelerator depression amount restriction unit 550 and a movement distance restriction unit 551, and includes an accelerator depression amount APO, a curb detection flag f_curb_up, f_curb_down, a movement distance dist_up, and dist_down. The target acceleration input tACC_IN is calculated based on the target acceleration tACC.

  The accelerator depression amount restriction unit 550 is controlled according to the flowchart shown in FIG. 10, and determines whether the curb detection flag f_curb_up is 0 and the curb detection flag f_curb_down is 0 in step S31. If both are 0, the process proceeds to step S32, and it is determined whether or not the accelerator depression amount APO is larger than a predetermined value α, that is, whether or not the driver's acceleration request is strong. If it is larger than the predetermined value α, the process proceeds to step S33, where tACC is substituted for the target acceleration tACC_A, and the process is terminated.

  On the other hand, if at least one of the curb detection flags f_curb_up and f_curb_down is not 0 in step S31, or if the accelerator operation amount APO is less than or equal to the predetermined value α in step S32, the process proceeds to step S34, and tACC is substituted for the target acceleration tACC_B. To finish the process.

  The movement distance limiting unit 551 is controlled according to the block diagram shown in FIG. That is, the target acceleration input switching unit 551A substitutes tACC_B for P_tACC when the target acceleration tACC_B is 0 or more, and substitutes tACC_B for M_tACC when the target acceleration tACC_B is smaller than zero.

  The acceleration target acceleration input restriction gain calculation unit 551B refers to the table of FIG. 12 showing the relationship between the movement distance dist_up and the acceleration target acceleration input restriction gain P_tACC_lim, and inputs the acceleration target acceleration input based on the movement distance dist_up. The limit gain P_tACC_lim is calculated. Thus, for example, by setting the distance dist_up1 at which the gain becomes 0 or more to the length of the wheel base, the target acceleration input tACC_IN is from the time when the front wheel enters the ascending portion of the curb 101 to the time when the rear wheel passes. 0, and the upper limit value of the target vehicle speed is limited to the vehicle speed when the curb approaches.

  The deceleration target acceleration input restriction gain calculation unit 551C refers to the table of FIG. 13 showing the relationship between the movement distance dist_down and the deceleration target acceleration input restriction gain M_tACC_lim, and based on the movement distance dist_down, inputs the target acceleration during deceleration. A limit gain M_tACC_lim is calculated. Thus, for example, by setting the distance dist_down1 at which the gain is 0 or more to the length of the wheel base, the target acceleration input tACC_IN is from the time when the front wheel enters the descending portion of the curb 101 until the rear wheel passes. 0 and the lower limit value of the target vehicle speed is limited to the vehicle speed when the curb approaches.

  Based on the values calculated by the target acceleration input switching unit 551A, the acceleration target acceleration input limit gain calculation unit 551B, and the deceleration target acceleration input limit gain calculation unit 551C, the target acceleration tACC_B ′ is equal to or greater than 0. It is calculated by multiplying P_tACC and P_tACC_lim, and when the target acceleration tACC_B is less than 0, the target acceleration tACC_B ′ is calculated by multiplying M_tACC and M_tACC_lim.

  Returning to FIG. 9, the target acceleration input tACC_IN is calculated by adding the target acceleration tACC_A output from the accelerator depression amount limiting unit 550 and the target acceleration tACC_B ′ output from the movement distance limiting unit 551.

  Returning to FIG. 6, the vehicle speed conversion unit 56 calculates the target vehicle speed tVSP based on the target acceleration input tACC_IN, the vehicle speed aVSP, and the control execution flag fSTART. The target vehicle speed tVSP is calculated by the control shown in the flowchart of FIG.

  That is, in step S41, it is determined whether or not the control execution flag fSTART is 1. If the control execution flag fSTART is 1, the process proceeds to step S42, and a value obtained by multiplying the previous value of the target vehicle speed tVSP by the target acceleration tACC and the control cycle is added to obtain the target vehicle speed tVSP. Further, the previous value of tVSP is updated with the target vehicle speed tVSP, and the process is terminated.

  On the other hand, when it is determined in step S41 that the control execution flag fSTART is 0, the process proceeds to step S43, the target vehicle speed tVSP and the previous value of tVSP are updated with the actual vehicle speed aVSP, and the process ends.

Returning to FIG. 6, the feedback compensator 57 (hereinafter, feedback is indicated as “F / B”) is an F that matches the actual vehicle speed aVSP with the target vehicle speed tVSP based on the difference between the target vehicle speed tVSP and the actual vehicle speed aVSP. / B output is calculated. F / B compensator include constructed PI compensator from the proportional gain K _P and the integral gain K _I, as shown in FIG. 6, for example, to suppress the influence of disturbance or the modeling error by F / B output.

  The feedforward output correction travel resistance calculation unit 58 (hereinafter, feedforward is indicated as “F / F”) is a table in FIG. 15 showing the relationship between the curb height Curb_h and the F / F output correction travel resistance dv_FF. The F / F output correction travel resistance dv_FF is calculated based on the curb height Curb_h.

  The F / F output correction unit 59 corrects the F / F output based on the F / F output correction running resistance dv_FF and the curb detection flags f_curb_up and f_curb_down. That is, when the curb detection flags f_curb_up and f_curb_down are 1, the F / F output correction running resistance dv_FF is added to the F / F output.

  The drive torque command value cTDR is calculated by adding the F / F output and the F / B output obtained as described above.

  Returning to FIG. 2, the travel resistance estimation unit 60 calculates the travel resistance estimation value dv_EST based on the vehicle speed aVSP and the drive torque command value cTDR. The running resistance estimated value dv_EST is estimated by a running resistance estimator shown in the block diagram of FIG.

  The running resistance estimated value dv_Est is calculated by the following equation (2).

dv_Est = cTDR · H (s) · e ^−Ls −H (s) / G _V0 (s) · aVSP
... (2)
Here, H (s) is a low-pass filter that determines the running resistance estimation performance, and is set as, for example, the following expression (3).

H (s) = 1 / (τ _C · s + 1) (3)
τ _C is a first-order lag time constant.

Further, the linear approximation model G _V0 (s) of the vehicle 100 to be controlled is represented by the following equation (4) as an integral characteristic.

G _V0 (s) = (1 / (M · Rt)) · (1 / s) (4)

  Returning to FIG. 2, the driving force distribution unit 70 calculates the engine torque command value cTE and the speed ratio command value cRATIO based on the driving torque command value cTDR, the vehicle speed aVSP, and the actual speed ratio aRATIO. The engine torque command value cTE and the gear ratio command value cRATIO are calculated by the control shown in the block diagram of FIG.

  That is, the transmission ratio command value setting unit 71 refers to the map of FIG. 18 showing the relationship between the vehicle speed aVSP, the drive torque cTDR, and the transmission ratio, and sets the transmission ratio command value cRATIO based on the vehicle speed aVSP and the drive torque command value cTDR. calculate. Here, the map of FIG. 18 is a map when a continuously variable transmission is used.

  The engine torque command value calculation unit 72 calculates the engine torque command value cTE using the following equation (5) based on the drive torque command value cTDR and the actual gear ratio aRATIO.

cTE = cTDR / (G _f · aRATIO) (5)
Here, G _f is a reduction ratio of the reduction gear.

  Returning to FIG. 2, the engine torque command value cTE is output to the engine ECU 7, and the throttle valve opening signal calculated based on the engine torque command value cTE is output to the throttle actuator 8. The throttle actuator 8 controls the driving torque of the engine 102 by controlling the throttle valve based on the throttle valve opening signal. Further, the gear ratio command value cRATIO is output to the transmission ECU 6, and the gear ratio of the continuously variable transmission 103 is controlled based on the gear ratio command value cRATIO.

  Here, the control performed by the curb detection unit 30 and the movement distance calculation unit 40 will be described with reference to FIG. FIG. 19 is a time chart illustrating the control performed by the curb detection unit 30 and the movement distance calculation unit 40 among the control performed by the present embodiment when the curb passes. In addition, the step number of the flowchart of FIG. 4 and the code | symbol of drawing of FIG.

  When entering the ascending portion of the curb 101 at which the road surface height increases at time t1 (FIG. 19B), the running resistance estimated value dv_Est (n) rises, and the estimated value dv_Est (n−1) at the previous calculation. The change amount Δdv_Est, which is the difference between the two, becomes larger than the predetermined value D_UP (FIG. 4-S13; Y, FIG. 19C). Further, the difference between the estimated running resistance value dv_Est (n) and the average value dv_Est_Ave is larger than the predetermined value Dp (FIG. 4-S14; Y, FIG. 19 (d)). As a result, it is determined that the curb 101 has entered the rising portion, and the curb detection flag f_curb_up is set to 1 (FIG. 4-S15, FIG. 19 (e)). Further, since the curb detection flag f_curb_up is set to 1, the calculation is performed based on the vehicle speed aVSP after the movement distance dist_up is cleared to 0 (FIG. 19A).

  When passing the rising part of the curbstone 101 at time t2 (FIG. 19B), the running resistance estimated value dv_Est (n) decreases and the change amount Δdv_Est becomes smaller than the predetermined value D_DOWN (FIG. 4-S17; Y, FIG. 19 (c)). Further, since the difference between the running resistance estimated value dv_Est (n) and the average value dv_Est_Ave is larger than the predetermined value Dm (FIG. 4-S18; N, FIG. 19 (d)), it is determined that the rising portion of the curb 101 has passed. As a result, the curb detection flag f_curb_up is set to 0 (FIG. 4-S20, FIG. 19E).

  When entering the descending part of the curb 101 where the road surface height decreases at time t3 (FIG. 19A), the running resistance estimated value dv_Est (n) decreases, and the estimated value dv_Est (n-1) at the previous calculation. Is smaller than the predetermined value D_DOWN (FIG. 4-S17; Y, FIG. 19C). Further, the difference between the estimated running resistance value dv_Est (n) and the average value dv_Est_Ave is smaller than the predetermined value Dm (FIG. 4-S18; Y, FIG. 19 (d)). As a result, it is determined that the curbstone 101 has entered the descending portion, and the curb detection flag f_curb_down is set to 1 (FIG. 4-S19, FIG. 19 (f)). Further, since the curb detection flag f_curb_down is set to 1, the movement distance dist_down is cleared to 0 and then calculated based on the vehicle speed aVSP (FIG. 19A).

  When passing the descending part of the curbstone 101 at time t4 (FIG. 19B), the running resistance estimated value dv_Est (n) rises and the change amount Δdv_Est becomes larger than the predetermined value D_UP (FIG. 4-S13; Y, FIG. 19 (c)). Further, since the difference between the estimated running resistance value dv_Est (n) and the average value dv_Est_Ave is smaller than the predetermined value Dp (FIG. 4-S14; N, FIG. 19 (d)), it is determined that the vehicle has passed the down curb 101. The curb detection flag f_curb_down is set to 0 (FIG. 4-S16, FIG. 19 (f)).

  Also, since the curb detection flags f_curb_up and f_curb_down are both 0 before time t1, between t2 and t3, and after t4 (FIG. 4-S21; Y), the average value dv_Est_Ave of the running resistance estimated value is updated (FIG. 4). -S22), between the times t1 and t2 and between t3 and t4, since one of the curb detection flags f_curb_up and f_curb_down is 1, it is not updated (FIG. 4-S21; N).

  The operation of this embodiment will be described with the above control being summarized and referring to FIGS. FIG. 20 is a diagram illustrating a scene in which the vehicle 100 passes through the rising portion of the curbstone 101. FIG. 21 is a time chart showing the state of the vehicle 100 in the conventional example. (A) is the vehicle speed aVSP, (b) is the accelerator depression amount APO, (c) is the throttle valve opening correction amount, (d) is the running resistance, and (e) is the road height Curb_h. FIG. 22 is a time chart showing the state of the vehicle 100 in the present embodiment. (A) is the vehicle speed aVSP, (b) is the accelerator depression amount APO, (c) is the target drive torque correction amount, (d) is the running resistance, and (e) is the road surface height Curb_h. FIGS. 21 and 22 show a state in which control is performed to keep the vehicle speed constant while the driver's accelerator depression amount is constant even when the vehicle 100 passes the rising portion of the curbstone 101 as shown in FIG. Show.

  First, a conventional example will be described with reference to FIG. At time t1, the accelerator depression amount increases and the vehicle 100 starts (FIGS. 21A and 21B). When the vehicle enters the ascending curb 101 at which the height of the road surface rises at time t2, the running resistance rapidly increases and the vehicle speed decreases (FIGS. 21A, 21D, and 21E). Therefore, although the drive torque of the vehicle 100 is increased by increasing the throttle valve opening correction amount and increasing the throttle valve opening (FIG. 21 (c)), let's restore the vehicle speed that has dropped after passing the curb. As the valve control is continued, the acceleration is greater than the acceleration required by the driver, and it takes time until the actual vehicle speed overshoots and converges to the target vehicle speed (FIG. 21 (a)). give.

  Next, the state of the vehicle 100 when the present invention is applied will be described with reference to FIG. At time t1, the accelerator depression amount increases and the vehicle 100 starts (FIGS. 22A and 22B). When entering the ascending curb 101 where the height of the road surface rises at time t2, the running resistance increases rapidly (FIGS. 22D and 22E). At this time, since the drive torque is corrected according to the target drive torque correction amount (FIG. 22C), an increase in the deceleration of the vehicle 100 is suppressed to suppress a decrease in the vehicle speed (FIG. 22A). Here, the height of the curb 101 is detected in advance before the vehicle 100 enters the curb 101, and the target drive torque correction amount is calculated based on the curb height. When it is detected that the vehicle has entered the curbstone 101, the driving torque can be quickly corrected according to the height of the curbstone, and a decrease in vehicle speed can be minimized.

  As described above, in the present embodiment, the drive torque command value cTDR is corrected according to the height of the curb 101 through which the vehicle 100 passes, so the increase / decrease in travel resistance due to the curb 101 is compensated to suppress changes in vehicle speed. This can prevent the driver from feeling uncomfortable.

  Further, since the correction of the drive torque command value cTDR is performed when the vehicle 100 enters the curbstone 101, the change in the vehicle speed can be suppressed by better compensating for the increase / decrease in travel resistance due to the curbstone 101.

  Furthermore, since the upper limit value of the vehicle speed is restricted from when the front wheel of the vehicle 100 enters the rising portion of the curb 101 until the rear wheel passes, the vehicle 100 is prevented from suddenly accelerating due to the driver's accelerator operation. it can.

  Furthermore, since the front wheel of the vehicle 100 enters the rising portion of the curb 101 and the rear wheel passes and the driver's accelerator depression amount APO becomes larger than the predetermined value α, the upper limit value of the vehicle speed is limited. The vehicle 100 can be prevented from suddenly accelerating due to the driver's accelerator operation, and when the driver's acceleration request is strong after passing the curb, the vehicle speed restriction can be canceled to achieve the desired acceleration.

  Furthermore, since it is detected that the vehicle 100 has entered the curb 101 based on the running resistance estimated based on the vehicle speed and the target drive torque, it is possible to reliably determine the entry to the curb 101, and the curb 101 The change in vehicle speed can be further compensated by better compensating for the increase / decrease in the running resistance due to.

  Furthermore, when the amount of change Δdv_Est of the running resistance estimated value is larger than the positive predetermined value D_UP and the value obtained by subtracting the running resistance estimated value average value dv_Est_Ave from the running resistance estimated value dv_Est is larger than the positive predetermined value Dp, It is determined that the vehicle has entered the rising portion 101. Further, when the amount of change Δdv_Est of the running resistance estimated value is smaller than the negative predetermined value D_DOWN and the value obtained by subtracting the running resistance estimated value average value dv_Est_Ave from the running resistance estimated value dv_Est is smaller than the negative predetermined value Dm, the curbstone 101 It is determined that the vehicle has entered the descending part. Therefore, it can be reliably determined that the vehicle has entered the curb 101, and the change in the vehicle speed can be further suppressed by better compensating for the increase / decrease in travel resistance due to the curb 101.

  Further, when the amount of change Δdv_Est of the running resistance estimated value is larger than the positive predetermined value D_UP and the value obtained by subtracting the average running value dv_Est_Ave of the running resistance estimated value from the running resistance estimated value dv_Est is smaller than the positive predetermined value Dp, It is determined that the lowering portion 101 has passed. Further, when the amount of change Δdv_Est of the running resistance estimated value is smaller than the negative predetermined value D_DOWN and the value obtained by subtracting the average running value dv_Est_Ave of the running resistance estimated value from the running resistance estimated value dv_Est is greater than the negative predetermined value Dm. It is determined that it has passed the rising part. Therefore, it can be reliably determined that the curb 101 has passed, and the change in the vehicle speed can be further suppressed by better compensating for the increase / decrease in travel resistance due to the curb 101.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

It is a block diagram which shows the driving force control apparatus of the vehicle in this embodiment. It is a block diagram which shows the driving force control apparatus of the vehicle in this embodiment. It is a flowchart which shows control of a control start determination part. It is a flowchart which shows control of a curb detection part. It is a block diagram which shows control of a movement distance calculating part. It is a block diagram which shows control of a driving force control part. It is the map which showed the relationship between vehicle speed, target drive torque, and accelerator depression amount. It is a block diagram which shows the characteristic of the vehicle which is drive | working the flat road. It is a block diagram which shows control of a target acceleration input restriction part. It is a flowchart which shows control of the accelerator depression amount restriction | limiting part. It is a block diagram which shows control of a movement distance restriction | limiting part. It is the table which showed the relationship between a movement distance and the target acceleration input restriction gain at the time of acceleration. It is the table which showed the relationship between movement distance and the target acceleration input restriction gain at the time of deceleration. It is a flowchart which shows control of a vehicle speed conversion part. It is the table which showed the relationship between curb height and running resistance for F / F output amendment. It is a block diagram which shows control of a running resistance estimation part. It is a block diagram which shows control of a driving force distribution part. It is the map which showed the relationship between a vehicle speed, a gear ratio, and drive torque. It is a time chart explaining the control content of the curb detection part and the movement distance calculation part. It is the figure which showed the scene where a vehicle passes the up curb where the height of a road surface rises. It is a time chart explaining control of a prior art example. It is a time chart explaining control of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control start switch 2 Brake switch 3 Ultrasonic sensor 4 Accelerator operation amount sensor 5 Vehicle speed sensor 6 Transmission ECU
7 Engine ECU
8 Throttle actuator 10 Driving force control ECU
20 control start determination unit 30 curb detection unit 40 travel distance calculation unit 50 driving force control unit 51 target driving torque map 52 engine model 53 travel resistance map 54 acceleration conversion unit 55 target acceleration input restriction unit 550 accelerator depression amount restriction unit 551 travel distance Limiting unit 551A Target acceleration input switching unit 551B Acceleration target acceleration input limit gain calculation unit 551C Deceleration target acceleration input limit gain calculation unit 56 Vehicle speed conversion unit 57 F / B compensator 58 F / F output correction travel resistance calculation unit 59 F / F output correction unit 60 Travel resistance estimation unit 70 Driving force distribution unit 71 Gear ratio command value setting unit 72 Engine torque command value calculation unit 100 Vehicle 101 Curb 102 Engine 103 Continuously variable transmission 104 Final gear 105 Drive wheel

Claims (11)

An engine that generates the driving force of the vehicle;
Target driving force calculating means for calculating a target driving force of the vehicle based on the accelerator depression amount;
Road height change amount detecting means for detecting a change amount of the road surface height due to a step in front of the traveling direction of the vehicle;
Target driving force correcting means for correcting the target driving force so as to compensate for an increase / decrease in running resistance when passing through the step based on the amount of change in the height of the road surface;
Target driving force control means for controlling the engine so as to realize the corrected target driving force;
A driving force control apparatus for a vehicle, comprising: Further comprising a transmission for shifting the rotational speed of the engine and transmitting it to the drive wheels;
2. The vehicle driving force control according to claim 1, wherein the target driving force control means controls the torque of the engine and the transmission gear ratio so as to realize the corrected target driving force. 3. apparatus. Further comprising step detecting means for detecting that the vehicle is passing the step,
3. The vehicle according to claim 1, wherein the target driving force correcting unit corrects the target driving force based on an amount of change in height of the road surface when the vehicle enters the step. Driving force control device. Target vehicle speed calculating means for calculating a target vehicle speed of the vehicle based on the target driving force;
Target driving force change means for changing the target driving force corrected by the target driving force correction means so that the vehicle speed approaches the target vehicle speed;
With
The vehicle driving force control device according to claim 3, wherein when the vehicle enters the step, the change of the target driving force is stopped for a predetermined time.   5. The vehicle driving force control device according to claim 4, wherein the predetermined time is a time required for the vehicle to enter the step and pass through the step.   5. The vehicle drive according to claim 4, wherein the predetermined time is a time from when the vehicle enters the step until the vehicle passes through the step and the accelerator depression amount becomes larger than a predetermined amount. Force control device. A running resistance estimating means for estimating a running resistance of the vehicle based on a vehicle speed and the target driving force;
7. The vehicle driving force control device according to claim 3, wherein the step detection unit detects that the vehicle is passing the step based on the running resistance. 8. .   The step detecting means has a positive second predetermined value obtained by subtracting an average value obtained by a predetermined number of times of calculation of the running resistance from the running resistance, wherein the change rate of the running resistance is greater than a positive first predetermined value. 8. The vehicle driving force control device according to claim 7, wherein when the value is larger than the value, it is determined that the vehicle has entered a step where the road surface height increases.   The step detecting means has a positive second predetermined value obtained by subtracting an average value obtained by a predetermined number of times of calculation of the running resistance from the running resistance, wherein the change rate of the running resistance is greater than a positive first predetermined value. The vehicle driving force control device according to claim 7 or 8, wherein when the value is smaller than the value, it is determined that the vehicle has passed through a step where the height of the road surface decreases.   The step detecting means has a fourth predetermined value in which the rate of change in the running resistance is smaller than a negative third predetermined value, and a value obtained by subtracting an average value obtained by calculating the running resistance a predetermined number of times from the running resistance is negative. The vehicle driving force control device according to any one of claims 7 to 9, wherein when the value is larger than the value, it is determined that the vehicle has passed a step where the height of the road surface increases.   The step detecting means has a fourth predetermined value in which the rate of change in the running resistance is smaller than a negative third predetermined value, and a value obtained by subtracting an average value obtained by calculating the running resistance a predetermined number of times from the running resistance is negative. The vehicle driving force control device according to any one of claims 7 to 10, wherein when the value is smaller than the value, it is determined that the vehicle has entered a step where the height of the road surface decreases.

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