JP3767261B2 - Vehicle travel control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicular travel control device that travels while maintaining a target vehicle speed calculated based on a target vehicle speed set by a driver or a deviation between an inter-vehicle distance from a preceding vehicle and a target inter-vehicle distance.
[0002]
[Prior art]
Conventional vehicle travel control devices are described, for example, in JP-A-3-153426 (hereinafter referred to as a first conventional example) and JP-A-6-191324 (hereinafter referred to as a second conventional example). What is known.
The first conventional example is provided with an auto-cruise control function for controlling the vehicle speed so as to maintain a preset vehicle speed, and when the vehicle slips, the throttle valve is closed in accordance with the slip amount to output the engine. In an auto cruise control system, an engine output control method is disclosed in which auto cruise control is prohibited during traction control.
[0003]
Further, in the second conventional example, the fuel injection device detects the slip amount of the vehicle, selects the target vehicle speed, and maintains the target vehicle speed by selecting the traction control for suppressing the accelerator signal in a direction to reduce the slip amount. Auto-cruise control that adjusts the rack position of the vehicle, and when traction control is established during auto-cruise control, auto-cruise control is canceled and at least the engine speed and the actual rack position are simulated to auto-cruise driving. An engine output control device for a vehicle is disclosed in which traction control is executed on a cruise accelerator signal, and auto-cruise control is restored simultaneously with the end of traction control.
[0004]
[Problems to be solved by the invention]
However, in the first and second conventional examples, when the traction control is executed, the auto-cruise control is prohibited or canceled, and the auto-cruise control is returned simultaneously with the end of the traction control. Therefore, there is no problem if the vehicle speed is high and, for example, it immediately exceeds the low friction coefficient road surface such as snowy road, freezing road, rainy road, etc., but when starting from a state where the vehicle is stopped on the low friction coefficient road surface When the drive wheels are idle and unable to start, the rotation of the drive wheels is suppressed by the traction control and the auto cruise control is prohibited or canceled at the same time, so that the drive wheels are stopped and thus the traction control is also stopped. Therefore, auto-cruise control is restarted again, and the drive wheels idle, and traction control is started accordingly. , Will repeat that auto-cruise control is prohibited or canceled, there is an unsolved problem that continues to state that can not be starting.
[0005]
  In addition, when the traction control is started, the road surface is a low coefficient of friction, so if the lateral force of the drive wheels decreases due to disturbance, the behavior will be disturbed and the steering wheel will need to be steered, but the traction control will start.TheBy prohibiting or canceling the auto cruise control, the driving force becomes zero and the grip force of the wheel can be recovered. However, when the driving force becomes zero, the traction control is stopped and the auto cruise control is started. As a result, there is an unsolved problem that the lateral force of the drive wheels is reduced and the steering wheel returns to a state where the operation is continued.
[0006]
Therefore, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, during driving control, driving force suppression means (traction control means) is in an operating state, vehicle behavior is disturbed, It is an object of the present invention to provide a vehicular travel control device that can avoid a disorder of vehicle behavior and a state in which the vehicle cannot start by stopping the travel control when a travel state in which the vehicle cannot start is started.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, a vehicular travel control apparatus according to claim 1 includes a travel control means for controlling at least a driving force so as to maintain a vehicle speed at a target vehicle speed, and a slip state of a drive wheel is a predetermined slip state. In a vehicular travel control device comprising driving force suppression means for suppressing control of driving force when larger,A predetermined traveling state that is at least one of a side slip state of the vehicle and a drive wheel slip state when the vehicle startsWhen the driving force suppressing means is in an operating state during the control of the traveling control means, and the traveling condition detecting means,Continue control of the travel control means when a predetermined travel situation is not detected,Control stop means for stopping the control of the travel control means when a predetermined travel situation is detected is provided.
[0008]
  In the invention according to claim 1, at least driving force control is performed by the travel control means for maintaining the vehicle speed at the target vehicle speed calculated to maintain the target vehicle speed or the inter-vehicle distance set by the driver at the target inter-vehicle distance. Even if the driving force suppression means is in the activated state, the running condition detection meansWhen startingDetects rotation stoppage of non-driven wheelsIn a state where it is impossible to startOr the steering wheelCounter steerSteering stateAnd the vehicle is skiddingYouPlaceIf a specific driving situation is not detected, the driving control meansContinue driving force control of theWhen the vehicle travels in a driving force restrained state in which the driving force is restrained by the driving force restraining means, and the traveling state detecting means detects that the driving state is a predetermined traveling state, the control stopping means stops the control of the traveling control means, and Avoid the driving situation.
[0009]
  According to a second aspect of the present invention, in the vehicular travel control apparatus according to the first aspect of the invention, the travel state detection means includes a steering state detection means for detecting a steering state of the driver, and the steering state detection means. When the steering state detected in the above becomes more than the predetermined steering stateDepending on the skidding condition of the vehicleIt is configured to detect a predetermined traveling state.
[0010]
  In the invention according to claim 2, for example, the driver can reduce the lateral force of the wheel by the steering state detecting means.Skidding due toAgainstCounter steerWhen the steering state is detected,The vehicle is slippingIt is detected that the vehicle is in a predetermined driving situation.
  Further, in the vehicle travel control device according to claim 3, in the invention according to claim 2, the steering state detecting means detects a steering angle detecting means for detecting a steering angle, and a steering change frequency detecting means for detecting the number of steering changes. The steering angular velocity detecting means for detecting the steering angular velocity and the steering angular acceleration detecting means for detecting the steering angular acceleration are used.
[0011]
  In the invention according to claim 3, the steering angle detecting means, the steering angle change number detecting means, the steering angular velocity detecting means, and the steering angular acceleration detecting means are adapted to prevent a predetermined steering state, that is, a decrease in lateral force of the driver's wheel. All steering states are accurately detected.
  Still further, in the vehicle travel control device according to claim 4, in the invention according to any one of claims 1 to 3, the travel state detection unit detects the wheel speed of the non-driven wheel.StepAnd when the non-driving wheel wheel speed detecting means has been in a stopped state for a predetermined time or longer when the driving force suppressing means is in an activated state.Depends on the slip state of the drive wheel when startingPredetermined running conditionStateIt is characterized by being configured to detect.
[0012]
  In the invention according to claim 4, when the vehicle is started by the travel control means at the start of the vehicle, when the driving wheel slips and the driving force suppression means is activated, the non-driving wheel wheel When it is detected by the speed detection means that the non-driving wheels continue to be stopped,In the drive wheel slip state at the startBy determining that the vehicle cannot start, the driving force control by the travel control unit is stopped, and the vehicle can start, for example, by a creep phenomenon.
[0013]
Still further, in the vehicle travel control device according to claim 5, in the invention according to any one of claims 1 to 4, the control stop unit issues a warning indicating the control stop when the control of the travel control unit is stopped. It is configured as described above.
In the invention according to claim 5, when the control stop unit stops the control of the travel control unit, the control stop unit is warned to stop the control so that the driver can surely recognize the stop of the travel control unit. , And shift to the driver's own start operation.
[0014]
【The invention's effect】
  According to the vehicle travel control device of the first aspect, when the driving force control unit is in the operating state while the driving control is being performed by the traveling control unit to maintain the set vehicle speed or the target inter-vehicle distance. In addition, the running condition detection means detects the rotation stop state of the non-driven wheels when startingDrive wheel slip state of starting andSteering wheelCounter steerSteering stateDue to at least one of the sideslip state of the vehicle byWhen the predetermined driving situation is not detected, the driving force is controlled by the driving control means by the driving force suppressing means, and the driving condition is detected by the driving condition detecting means. In such a case, the control stopping unit can stop the control of the traveling control unit, avoiding a predetermined traveling state, and stabilizing the behavior.
[0015]
  Further, according to the vehicle travel control device of the second aspect, the steering state detecting means is configured such that, for example, the driver operates the steering wheel by reducing the lateral force of the wheel.Counter steerPredetermined due to skidding of the vehicle in the steering stateRunning situationIs detectedRunBy stopping the control by the row control means, the driving force becomes zero and the wheel grip force is restored.To eliminate skiddingThus, the effect that the behavior can be stabilized is obtained.
[0016]
  Further, according to the vehicle travel control apparatus of the third aspect, the steering angle detection means and the steering state detection means are constituted by the steering angle change frequency detection means, the steering angular velocity detection means, and the steering angular acceleration detection means. ofRunning situationThat is, the driver is caused by a decrease in the lateral force of the wheelIn a skidding stateSteering wheelCounter steerThe effect that the steering state can be accurately detected is obtained.
[0017]
  Furthermore, according to the vehicle travel control device of the fourth aspect, when the vehicle is started by the travel control means, if the drive wheel slips and the drive force suppression means is activated, the drive is not driven. When it is detected by the wheel speed detection means that the non-driving wheel continues to be stopped,In the drive wheel slip state at the startBy determining that the vehicle is in an unstartable state, it is possible to obtain an effect that the driving force control by the traveling control unit is stopped and the vehicle can be reliably started by, for example, a creep phenomenon by an operation of the driver.
[0018]
Still further, according to the vehicle travel control device of the fifth aspect, when the control stop means stops the control of the travel control means, the control of the travel control means is given to the driver by warning the stop of the control. The effect of allowing the driver to recognize the stop and to shift to the start operation of the driver himself / herself is obtained.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a first embodiment when the present invention is applied to a rear wheel drive vehicle equipped with a preceding vehicle follow-up control device that travels following a preceding vehicle. In the drawing, 1FL, 1FR Is a front wheel as a driven wheel, 1RL and 1RR are rear wheels as drive wheels, and the rear wheels 1RL and 1RR are driven by an engine 2 with an automatic transmission 3, a propeller shaft 4, a final reduction gear 5 and an axle 6 And is driven to rotate.
[0020]
The front wheels 1FL, 1FR and the rear wheels 1RL, 1RR are each provided with a disc brake 7 as a brake actuator that generates a braking force, and the braking hydraulic pressure of these disc brakes 7 is controlled by a braking control device 8.
Here, the braking control device 8 generates a braking hydraulic pressure in response to depression of a brake pedal (not shown), and a braking pressure command value P from a follow-up control controller 20 described later._BCThe brake hydraulic pressure is generated in response to the above.
[0021]
The engine 2 is provided with an engine output control device 11 that controls the output thereof. In this engine output control device 11, the depression amount of an accelerator pedal (not shown) and a throttle opening command value TH from a follow-up control controller 20 which will be described later._RThe throttle actuator 12 that adjusts the throttle opening provided in the engine 2 according to the control is controlled, and at least the throttle opening so as to suppress the wheel slip at the time of sudden acceleration or low friction coefficient road running A traction control device 13 is provided for controlling the traction.
[0022]
The traction control device 13 is configured to generate a wheel speed V based on wheel speed pulses output from wheel speed sensors 10FL to 10RR provided on the wheels 1FL to 1RR._WFL~ V_WRRTo calculate the wheel speed V on the front wheel side as a driven wheel._WFLAnd V_WFRCalculate the average value of the vehicle speed V_STo calculate the vehicle speed V_SAnd rear wheel speed V as drive wheel_WRLAnd V_WRRThe driving wheel slip ratio is calculated based on the above, and the throttle opening is controlled so that it matches the target slip ratio to prevent wheel slip during acceleration, and a logical value is obtained during traction control. “1”, a control state signal TR that becomes a logical value “0” when not in control is output to the follow-up control controller 20 described later, and the calculated vehicle speed V_SAnd front wheel speed V_WFL,V_WFRIs output to the controller 20 for tracking control.
[0023]
On the other hand, the lower part of the vehicle body on the front side of the vehicle has a radar-type configuration that sweeps laser light as an inter-vehicle distance detecting means for detecting an inter-vehicle distance from the preceding vehicle and receives reflected light from the preceding vehicle. An inter-vehicle distance sensor 14 is provided.
Further, the vehicle is provided with a steering angle sensor 15 that detects the steering angle θ of the steering wheel.
[0024]
The control state signal TR output from the traction control device 13 and the vehicle speed V_SAnd front wheel speed V_WFL,V_WFThe inter-vehicle distance L output from the inter-vehicle distance sensor 14 and the steering angle θ output from the steering angle sensor 15 are input to the follow-up control controller 20, and the follow-up control controller 20 captures the preceding vehicle. When the vehicle is moving, the vehicle distance is controlled to the target vehicle distance, and when the preceding vehicle is not captured, the vehicle speed V_SThe vehicle speed V is set by the driver_SETBraking pressure command value P_BRAnd target throttle opening TH_RIs output to the braking control device 8 and the engine output control device 11, and when the follow-up control is stopped, a control stop display is displayed on the display 21 such as a liquid crystal disposed at a position visible from the driver's seat.
[0025]
The follow-up control controller 20 includes a microcomputer and its peripheral devices, and constitutes a control block shown in FIG. 2 according to the software form of the microcomputer.
This control block measures the time from when the inter-vehicle distance sensor 14 sweeps the laser light until the reflected light of the preceding vehicle is received, and calculates the inter-vehicle distance L with the preceding vehicle, The inter-vehicle distance L calculated by the ranging signal processing unit 21 and the own vehicle speed V read from the traction control device 13_SBased on the target vehicle distance L^*Target vehicle speed to maintain at V^*And a target vehicle speed V calculated by the inter-vehicle distance control unit 40 as inter-vehicle distance control means.^*Based on the target drive shaft torque T^*The vehicle speed control unit 50 for calculating the target drive shaft torque T calculated by the vehicle speed control unit 50^*Based on the target throttle opening TH for the throttle actuator 12 and the brake actuator 7_RAnd target braking pressure P_BRAnd a driving wheel shaft torque control unit 60 that outputs these values to the throttle actuator 13 and the brake actuator 7.
[0026]
The inter-vehicle distance control unit 40 receives the vehicle speed V input from the traction control device 13._SBased on the target inter-vehicle distance L between the preceding vehicle and the vehicle^*The target inter-vehicle distance setting unit 42 for calculating the target inter-vehicle distance L calculated by the target inter-vehicle distance setting unit 42^*The inter-vehicle distance L input from the ranging signal processing unit 21 and the own vehicle speed V_SAnd the target inter-vehicle distance L based on^*Target vehicle speed V to match^*The inter-vehicle distance control calculation unit 43 is provided.
[0027]
When the vehicle speed control unit 50 is in the follow-up control state, the target vehicle speed V input from the inter-vehicle distance control unit 40 when the preceding vehicle is captured by the inter-vehicle distance sensor 14._L ^*And the set vehicle speed V set by the driver_SETOr the smaller value of the target vehicle speed V^*The vehicle speed V is set by the driver when the preceding vehicle is not captured._SETThe target vehicle speed V^*Target vehicle speed setting unit 51 set as, and target vehicle speed V set by this target vehicle speed setting unit 51^*Own vehicle speed V_STarget drive shaft torque T for matching_W ^*And a target drive shaft torque calculation unit 52.
[0028]
Further, as shown in FIG. 3, the drive shaft torque control unit 60 generates a target drive torque T_W ^*Throttle opening command value θ to achieve_RAnd brake fluid pressure command value P_BRAnd
Now, the torque amplification factor of the torque converter is RT, and the gear ratio of the automatic transmission 3 is R._AT, The differential gear ratio is R_DEF, Engine inertia J_E, Engine speed N_EThen, the drive shaft torque T_WAnd engine torque T_EAnd brake torque T_BRCan be expressed by the following equation (1).
[0029]
T_W= K_GEAR{T_E-J_E(DN_E/ Dt)}-T_BR  ………… (1)
However, K_GEAR= R_T・ R_AT・ R_DEF
Therefore, the target drive shaft torque T_W ^*Against the target engine torque T_E ^*To calculate this target engine torque T_E ^*Throttle opening command value θ_RIs calculated with reference to the engine map shown in FIG.
[0030]
T_E ^*= J_E(DN_E/ Dt) + T_W ^*/ K_GEAR      ………… (2)
Here, the throttle opening command value θ_RIs equal to or greater than “0”, the target drive shaft torque T can be obtained only by the engine torque without using the brake._W ^*The torque of the street can be realized.
On the other hand, the throttle opening command value θ_RIs less than “0”, the throttle opening is set to “0”, and the drive shaft torque is set to the target drive shaft torque T in consideration of the drive shaft torque output by the engine 2 at this time._W ^*The amount of brake operation to match is calculated.
[0031]
Thus, the target engine torque T_E ^*And target brake torque T_BR ^*The distribution control law is as follows.
(A) Throttle opening command value θ_RWhen> 0
T_BR ^*= 0
Therefore, the equation (1) becomes the following equation (3).
[0032]
T_W= K_GEAR{T_E-J_E(DN_E/ Dt)} (3)
Therefore, the target drive shaft torque T_W ^*The target engine torque T of the following equation (4)_E ^*It is sufficient to generate
T_E ^*= J_E(DN_E/ Dt) + T_W ^*/ K_GEAR      ………… (4)
Here, target brake torque T_BRIs “0”, so the brake fluid pressure command value P_BRBecomes “0”.
(B) Throttle opening command value θ_RWhen ≦ 0
Engine speed N_EReferring to the engine torque map shown in FIG._REngine torque T when is 0_E0Is calculated. Thereby, said (1) Formula turns into following (5) Formula.
[0033]
T_W= K_GEAR{T_E0-J_E(DN_E/ Dt)}-T_BR  ............ (5)
Therefore, the target drive shaft torque T_W ^*Target brake torque T against_BR ^*Is represented by the following equation (6).
T_BR ^*= -T_W ^*+ K_GEAR{T_E0-J_E(DN_E/ Dt)} …… (6)
Where Brake cylinder area is A_B, Rotor effective radius R_B, Pad friction coefficient μ_BThen, the target brake torque T_BR ^*On the other hand, the brake fluid pressure command value P which is the brake operation amount_BRCan be expressed by the following equation (7).
[0034]
P_BR= (1 / K_BT) ・ T_BR ^*    ............ (7)
However, K_BT= 8 ・ A_B・ R_B・ Μ_B
For this reason, the drive shaft torque control unit 60, as shown in the block diagram of FIG._W ^*To the divider 61 and the coefficient K_GEARDivided by the target engine torque T_E ^*Is supplied to the throttle opening degree calculation unit 62, and the target engine torque T is calculated by the throttle opening degree calculation unit 62._E ^*And engine speed N_EThe throttle opening TH is calculated with reference to the engine map of FIG. 4 and supplied to the limiter 63 to limit the range from zero to the maximum throttle opening that can be controlled by the throttle actuator 12. Throttle opening command value TH_ROutput to the engine output control device 11 as well as the target drive shaft torque T_W ^*Is supplied to the subtractor 64, and this target drive shaft torque T_W ^*Is the value K calculated by the engine brake correction calculation unit 65 that performs the calculation of the second term on the right side of the equation (6)._GEAR{T_E0-J_E(DN_E/ Dt)} is subtracted from the target brake torque T_BR ^*Is supplied to the divider 66, and the brake fluid pressure command value P is calculated by performing the calculation of the equation (7)._BIs limited by a limiter 67 to a range from zero to the maximum braking pressure that can be controlled by the brake actuator 7, and the brake fluid pressure command value P is calculated._BRIs output to the braking control device 8.
[0035]
On the other hand, the tracking control controller 20 executes a control management process shown in FIG. In this control management process, first, in step S1, a set switch (not shown) is turned on to set the vehicle speed V set by the driver._SETOwn vehicle speed V_SOr the target inter-vehicle distance L^*It is determined whether or not the follow-up control state flag FS indicating whether or not the follow-up control state coincides with "1" indicating the follow-up control state, and the follow-up control state flag FS is reset to "0". If the follow-up control state flag FS is set to “1”, the process proceeds to step S2, and the control state signal TS input from the traction control device 13 is a logical value. It is determined whether or not it is “1”, and when the control state signal TS is the logical value “0”, it is determined that the traction control is not executed, and the process proceeds to step S3, where the above-mentioned inter-vehicle distance control unit 40. After performing the follow-up control process by the vehicle speed control unit 50 and the drive shaft torque control unit 60, the process returns to step S1, and the control state signal TS is a logical value “1”. The it is judged that the traction control has been started, the process proceeds to step S4.
[0036]
In step S4, the steering angle θ of the steering angle sensor 15 is read, and the steering angle θ is set in advance._SIt is determined whether or not, θ ≧ θ_SIf so, the process proceeds to step S5, a control stop display indicating that the follow-up control is stopped is performed on the display 21 such as a liquid crystal disposed at a position visible from the driver's seat, and then the process proceeds to step S6. Then, the follow-up control state flag FS is reset to “0”, the follow-up control in step S3 is stopped, and the process returns to step S1.
[0037]
In addition, the determination result of step S4 is θ <θ_SWhen it is, the process proceeds to step S7, where the front wheel speed V as the driven wheel is_WFLAnd V_WFRIs determined to be “0”, and when it is “0”, the process proceeds to step S8, where the front wheel speed V_WFLAnd V_WFRIs the state of “0” for a predetermined time t_SIt is determined whether or not the time has elapsed, and a predetermined time t_SWhen the time has not elapsed, the process returns to step S1, and the predetermined time t_SWhen elapses, the process proceeds to step S5.
[0038]
Next, the operation of the above embodiment will be described.
Now, for example, in a state where a set switch (not shown) is turned on and the follow-up control state flag FS is set to “1”, for example, the set vehicle speed V set by the driver by capturing the preceding vehicle, for example._SETLower vehicle speed V_SAnd the traction control device 13 is in a non-operating state. In this state, in the process of FIG. 6, the tracking control process corresponding to FIG. 2 is executed by moving from step S1 to step S3 through step S2, and the vehicle speed V_SBased on the target inter-vehicle distance L^*Is calculated, and then the target vehicle speed V_L ^*Is calculated, and this target vehicle speed V_L ^*Is the target vehicle speed V^*Selected as the target vehicle speed V^*And own vehicle speed V_SSpeed gain K_SPDriving force F calculated by multiplying_WRTo estimated running resistance F_DHTo subtract the target driving force F_W ^*And the tire radius R_HIs multiplied by the target drive shaft torque T_W ^*To calculate the target drive shaft torque T_WBased on the throttle opening command value TH_RAnd brake fluid pressure command value P_BRAre calculated and output to the engine output control device 11 and the brake control device 8 to obtain the target vehicle distance L.^*The driving force or the braking force is controlled so as to match the above.
[0039]
In this follow-up running state, the vehicle travels on a straight road with a low friction coefficient road surface such as a snowy road, a frozen road, a rainy road, etc., and as shown in FIG. When the wheel slip rate exceeds the target slip rate at time t2, the traction control device 13 is activated and the throttle is opened so that the wheel slip rate falls below the target slip rate. Degree command value TH_RLimit.
[0040]
As described above, when the traction control device 13 is activated, as shown in FIG. 7A, the control state signal TS becomes the logical value “1”, so that in the process of FIG. When the vehicle is traveling on a straight road and the vehicle does not skid, the steering angle θ detected by the steering angle sensor 15 is substantially “0”. Therefore, the process proceeds to step S7 as a driven wheel. The front wheels 1FL and 1FR are rotating and the wheel speed V_WFLAnd V_WFRAre both larger than “0”, the process proceeds to step S3 to continue the follow-up control.
[0041]
In a running state in which the traction control is performed on the road surface with the low friction coefficient, when the vehicle starts to slip, for example, at the time t3, the driver starts steering the steering wheel in the skidding direction. The counter steer state is reached, and the steering angle θ is set at the time t4 as shown in FIG. 7C._SIf it becomes above, it will transfer to step S5 from step S4 in the process of FIG. 6, will perform the control stop display to the effect that the tracking control will be stopped on the display 21 and warn the driver to stop the tracking control, then step The process proceeds to S6, the follow-up control is stopped as shown in FIG.
[0042]
At this time, since the driver is in the follow-up control state and does not depress the accelerator pedal, the driving force immediately becomes “0”, and the gripping force of the rear wheels 1RL and 1RR as the driving wheels recovers. The skid state is eliminated, the behavior of the host vehicle can be stabilized, and the counter steer state can be eliminated.
Incidentally, in the conventional example, as shown in FIG. 8, when the traction control is started when the wheel slip ratio generated in the drive wheel at the time t11 exceeds the target slip ratio, the throttle opening is suppressed, Although the wheel speed of the driving wheel is limited, by continuing the state in which the driving force is transmitted to the driving wheel, the wheel slip state continues and the lateral force of the driving wheel remains reduced. In order to deal with this, the driver steers the steering wheel to make a counter-steer state, but the state where the driving force is transmitted continues. The counter-steer state needs to be continued, and the follow-up control must be canceled at the driver's will, resulting in a decrease in running stability.
[0043]
Thereafter, the vehicle stops on the low friction coefficient road surface in a state where the preceding vehicle is captured by a signal or the like, and in this state, the set switch is turned on and the traveling state flag FS is set to “1”. When the process shifts from step S2 to step S3 in the process of 6 and returns to the follow-up control state, when the preceding vehicle is stopped, the host vehicle is also maintained in the stopped state, and the preceding vehicle is started, so that the inter-vehicle distance L Increases and the target inter-vehicle distance L^*Exceeding the target vehicle speed V corresponding to this_L ^*Is calculated and the target drive shaft torque T according to this is calculated._W ^*Is calculated, and in response to this, the throttle opening command value TH_RIncreases in the opening direction, driving force is generated in the engine 2 and is transmitted to the driving wheels 1RL and 1RR via the automatic transmission 3, the propeller shaft 4, the final reduction gear 5 and the driving shaft 6. These drive wheels 1RL and 1RR are rotationally driven from time t21 as shown in FIG. 9 (b).
[0044]
At this time, since the road surface has a low friction coefficient, wheel slip occurs on the drive wheels 1RL and 1RR, and the traction control device 13 is activated to limit the throttle opening TH at time t22, so that the host vehicle starts. When this is done, the front wheels 1FL and 1FR as driven wheels rotate as shown by broken lines in FIG._WFLAnd V_WFRBecomes a value larger than “0”. Therefore, in the process of FIG. 6, the process proceeds from step S4 to step S7 to step S3, and the tracking control process is continued to start following the preceding vehicle.
[0045]
However, when a large wheel slip occurs in the driving wheels 1RL and 1RR at the time of starting, the vehicle does not start and the front wheels 1FL and 1FR as driven wheels are kept in a rotation stopped state. In the process, the process proceeds from step S7 to step S8, and the predetermined elapsed time t_SUntil the time elapses, the process proceeds to step S3 and the follow-up control process is continued.
[0046]
Thereafter, the front wheels 1FL and 1FR as driven wheels continue to stop rotating, and a predetermined elapsed time t at time t23._SWhen the time elapses, it is determined that the vehicle is unable to start, and the process proceeds from step S8 to step S5. After the control stop display indicating that the tracking control is stopped is displayed on the display unit 21, the process proceeds to step S6. By stopping as shown in (d), the throttle opening TH is returned to "0", that is, the fully closed state, and the host vehicle can be started with a small driving force due to the creep phenomenon of the automatic transmission.
[0047]
Incidentally, in the conventional example, when the vehicle is started by auto-cruising from the stop state of the own vehicle on the low friction coefficient road surface, when a large wheel slip occurs on the drive wheel and the vehicle cannot start, FIG. As shown in a), when the traction control is activated at time t31, the auto cruise control is canceled, but the cruise accelerator signal simulated by the accelerator signal for obtaining the vehicle speed during the auto cruise is calculated, and this cruise is Since the traction control is performed on the accelerator signal, the throttle opening is limited to a small value, and when the wheel slip of the driving wheel is settled and the traction control is finished at time t32, the control returns to the auto cruise control again and the wheel slip occurs. Will be repeated and the driver will automatically It will be continued until the release the loose control.
[0048]
In the above embodiment, the steering angle θ is set as the steering angle θ in the counter-steer state of the driver._SAlthough the case of detecting when the above is described is not limited to this, the number of changes in the steering angle θ, the steering angular velocity, and the steering angular acceleration are detected, and the counter steer state is detected based on these. You may make it do.
In the above embodiment, the case where the control stop display is performed on the display 21 when the follow-up control is stopped has been described. However, the present invention is not limited to this, and an alarm sound is generated by applying an alarm sound generator. In short, what is necessary is just to be able to warn the driver that the follow-up control is to be stopped.
[0049]
Furthermore, in the above embodiment, the case where the present invention is applied to the follow-up control device has been described. However, the present invention is not limited to this, and the present invention is applied to any vehicle speed control that makes the host vehicle speed coincide with the target vehicle speed. To get.
Furthermore, in the above embodiment, the wheel speed V of the front wheels 1FL and 1FR as driven wheels._WFLAnd V_WFRVehicle speed V_SHowever, the present invention is not limited to this, and in a vehicle equipped with an antilock brake control device, the vehicle body speed calculated by the vehicle body speed estimation unit incorporated in the antilock brake control device is automatically determined. Vehicle speed V_SYou may make it set as.
[0050]
Furthermore, in the above-described embodiment, the case where the braking force is generated by controlling the braking pressure of the brake actuator 7 constituted by the disc brake has been described. However, the present invention is not limited to this. In the case where an electric motor is applied, the present invention can be applied to a case where the electric output to the electric motor is controlled and a regenerative braking force is generated by the electric motor as in an electric vehicle.
[0051]
In the above embodiment, the case where the present invention is applied to a rear wheel drive vehicle has been described. However, the present invention can also be applied to a front wheel drive vehicle, and the case where the engine 2 is applied as a rotational drive source will be described. However, the present invention is not limited to this, and an electric motor can be applied. Furthermore, the present invention can be applied to a hybrid vehicle using an engine and an electric motor.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.
FIG. 2 is a block diagram showing a specific configuration of the follow-up control controller in FIG. 1;
FIG. 3 is a block diagram showing a specific example of a drive shaft torque control unit in FIG. 2;
FIG. 4 is a characteristic diagram showing an example of an engine map for obtaining engine torque from the throttle opening.
FIG. 5 is a characteristic diagram for obtaining the engine torque from the engine speed when the throttle opening is zero.
6 is a flowchart showing an example of a control management process of the follow-up control controller in FIG. 1;
7 is a time chart for explaining an operation when a side slip occurs in the embodiment of FIG. 1; FIG.
FIG. 8 is a time chart for explaining an operation when a side slip occurs in a conventional example.
FIG. 9 is a time chart for explaining the operation at the start of the embodiment of FIG. 1;
FIG. 10 is a time chart for explaining the operation at the start of the conventional example.
[Explanation of symbols]
2 Engine
3 Automatic transmission
7 Brake actuator
8 Braking control device
10FL-10RR Wheel speed sensor
11 Engine output control device
12 Throttle actuator
13 Traction control device
14 Inter-vehicle distance sensor
15 Steering angle sensor
20 Tracking control controller
21 Display
40 Inter-vehicle distance controller
50 Vehicle speed control unit
56 Running resistance estimation unit

Claims (5)

A vehicle equipped with a travel control unit that controls at least a driving force so as to maintain a vehicle speed at a target vehicle speed, and a driving force suppression unit that controls driving force when a slip state of a drive wheel is larger than a predetermined slip state In the travel control device, a travel condition detection means for detecting a predetermined travel condition that is at least one of a side slip state of the vehicle and a drive wheel slip state at the start of the vehicle , and the driving force suppression means during the control of the travel control means When the driving state is not detected by the driving state detection means, the control of the driving control unit is continued when the driving state detection unit does not detect the predetermined driving state, and the control of the driving control unit is detected when the predetermined driving state is detected. A vehicle travel control device comprising: control stop means for stopping the vehicle. The running condition detecting means includes steering state detecting means for detecting a steering state of the driver, predetermined by skid state of the vehicle when the detected steering state is equal to or greater than a predetermined steering state at the steering state detecting means The vehicle travel control device according to claim 1, wherein the vehicle travel control device is configured to detect a travel state. The steering state detecting means includes a steering angle detecting means for detecting a steering angle, a steering angle change frequency detecting means for detecting a steering angle change frequency, a steering angular velocity detecting means for detecting a steering angular velocity, and a steering angular acceleration for detecting a steering angular acceleration. The vehicular travel control apparatus according to claim 2, wherein the vehicular travel control apparatus comprises any one of detecting means. The running condition detecting means includes a non-driven wheel speed detecting means to detect the wheel speeds of non-driving wheels, when the driving force suppressing means becomes operating state, in the non-driven wheel speed detecting means claims 1 to 3 detected non-driven wheel speed is characterized in that it is configured to detect a predetermined traveling state by the driving wheel slip state at the start when been off for a predetermined time or more The vehicle travel control device according to any one of the above. The vehicle travel control device according to any one of claims 1 to 4, wherein the control stop unit is configured to issue a warning indicating control stop when the control of the travel control unit is stopped. .

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