JP3637842B2 - Vehicle motion control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle motion control device that ensures traveling stability of a vehicle by motion control in the vehicle longitudinal direction.
[0002]
[Prior art]
Conventionally, as a traction control device that controls the longitudinal movement of a vehicle, throttle control that closes the throttle to reduce engine torque (drive torque) and brake control that brakes the drive wheels to suppress slip are generally known. It has been. As a traction control device combining these throttle control and brake control, for example, a technique described in Japanese Patent Laid-Open No. 6-80049 is known.
[0003]
In this publication, the slip tendency of the drive wheel is determined based at least on the comparison result between the determination reference value determined by adding the slip ratio to the vehicle body speed and the drive wheel speed, and the drive wheel speed becomes equal to or higher than the determination reference value. When the condition continues, the engine output is reduced to the target value, the brake device is operated according to the degree of slip tendency, and after the drive wheel speed becomes less than the criterion value, the drive wheel When the speed is less than the criterion value, the engine output is increased according to the degree of slip tendency and the brake device is deactivated. When the driving wheel speed exceeds the criterion value, the engine output is maintained and the brake device is It is described that it is operated according to the degree of slip tendency.
[0004]
[Problems to be solved by the invention]
However, in the conventional traction control device, when the driving wheel speed exceeds a reference speed set in advance considering the slip ratio, control for suppressing the engine output and control for operating the brake device are performed. Since the control is to increase the engine output so that the speed is less than the reference speed and to control the brake device to be inactive, the drive wheel speed is set based on the slip ratio during traction control. The speed will be repeatedly increased or decreased, but depending on the road surface μ, etc., the driving wheel will increase greatly, leading to fluctuations in the front-rear G, etc. was there.
[0005]
In addition, when the driving wheel speed exceeds the reference speed set in consideration of the slip ratio, control to suppress the engine output and control to operate the brake device are performed, and when the driving wheel speed becomes less than the reference speed, the engine output is increased. Therefore, if the reference speed is set so that the slip ratio is small in order to suppress fluctuations in the drive wheels, the acceleration performance deteriorates. there were.
[0006]
In view of this, the present applicant previously proposed an apparatus equipped with a drive wheel speed servo calculation means for calculating a drive wheel torque command value by servo calculation that eliminates the deviation between the target drive wheel speed calculation value and the drive wheel speed detection value. did.
[0007]
Unlike the conventional traction control based on the slip ratio, this vehicle motion control device is characterized in that a sufficient driving force can be obtained while suppressing fluctuations in the driving wheel by using the driving wheel speed servo system. ing.
[0008]
However, the previously proposed vehicle motion control device uses the driving wheel speed output of the vehicle model configured based on the vehicle data measured in advance as the target driving wheel speed when the traction control is not operated, and when the traction control is operated, Since the target drive wheel speed is calculated in accordance with the non-drive wheel speed, the drive wheel state, etc., the vehicle model for each vehicle to be controlled in advance for the drive wheel speed servo calculation when the traction control is not operated. It is necessary to prepare.
[0009]
The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to provide a simple control system that does not require the preparation of a vehicle model for each vehicle, An object of the present invention is to provide a vehicle motion control device capable of achieving both a smooth acceleration feeling in which the longitudinal G is suppressed even when there is a change, and a good acceleration performance.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, at least one of throttle control and brake control is used.Based on drive wheel slip rateIn a vehicle motion control device provided with traction control means for controlling drive wheel torque,
Traction control operation state determining means for determining whether the traction control is operating or when the traction control is not operating;
Traveling state detecting means for detecting the traveling state of the vehicle;
Target drive wheel speed calculating means for calculating the target drive wheel speed based on the running state detection value;
Driving wheel speed detecting means for detecting the driving wheel speed of the vehicle;
Drive wheel torque by servo calculation that eliminates the deviation between the target drive wheel speed calculation value and the drive wheel speed detection value only when traction control is activatedControlDriving wheel speed servo calculation means,
  The drive wheel speed servo calculation means does not control the drive wheel torque by the drive wheel speed servo calculation immediately after the traction control operation, and generates the drive wheel torque based on the slip ratio of the drive wheel after the drive wheel slip occurs. Wait for convergence of drive wheel slip by traction control to be controlled, and then control drive wheel torque by drive wheel speed servo calculationIt is characterized by that.
[0012]
  Claim 2In the described invention,Claim 1In the described vehicle motion control device,
From the time immediately after the traction control operation until the drive wheel speed servo calculation is performed,Based on the throttle command value based on the drive wheel slip amount, the throttle command value based on the drive wheel acceleration, the throttle command value based on the non-drive wheel acceleration, the throttle command value based on the vehicle speed, and the elapsed time from the start of the traction control operation The throttle command value is determined by select low with the throttle command value.Control by a throttle control means is performed.
[0014]
  Claim 3In the described invention, claim 1 is provided.Or 2In the described vehicle motion control device,
If the accelerator opening by the driver's operation and the throttle opening by the actuator operation are equal during the traction control and driving wheel speed servo calculation, the traction control operation is terminated at the same time when both opening positions are equal, and the drive A first control ending means for ending the wheel speed servo calculation is provided.
[0015]
  Claim 4In the described invention, claims 1 toIn any one of Claim 3In the described vehicle motion control device,
During driving wheel speed servo calculation during traction control, if the deviation between the driving wheel speed and the non-driving wheel speed remains within the set value for a set time, the drive wheel speed servo calculation is terminated when the set time elapses, Thereafter, the throttle valve is slowly opened to the accelerator opening, and second control ending means for ending the traction control when the throttle opening becomes equal to the accelerator opening is provided.
[0016]
Operation and effect of the invention
  In the first aspect of the present invention, first, the traction control operation state determination means determines whether the traction control is operating or when the traction control is not operating. Then, the traveling state of the vehicle is detected by the traveling state detection means, the target driving wheel speed calculation means calculates the target driving wheel speed based on the traveling state detection value, and the driving wheel speed detection means detects the driving wheel of the vehicle. Only when the speed is detected and it is determined that the traction control is in operation, the driving wheel torque is calculated by the servo calculation that eliminates the deviation between the target driving wheel speed calculation value and the driving wheel speed detection value in the driving wheel speed servo calculation means. The command value is calculated, and the drive wheel torque is controlled by at least one of throttle control and brake control in the traction control means based on the output of the drive wheel torque command value.
In other words, in the prior art, since the traction control was performed based on the slip ratio, there was a problem that the fluctuation of the drive wheel speed became large, and the acceleration was achieved when a low slip ratio was set to suppress the fluctuation of the drive wheel. There was a problem that the sex deteriorated.
On the other hand, in the invention described in claim 1, since the traction control using the driving wheel speed servo system that matches the driving wheel speed to the target driving wheel speed is used instead of the traction control based on the slip ratio reference, the fluctuation of the driving wheel speed is changed. Is kept small, and it is possible to accelerate smoothly, and it is also possible to ensure a sufficient driving force by setting the target driving wheel speed.
Furthermore, since it is not necessary to prepare a vehicle model for driving wheel speed servo calculation at the time of traction control operation, it is possible to save the effort of creating a vehicle model, and when configuring a system using an in-vehicle microcomputer, the program amount Therefore, it is possible to perform control calculation with a cheaper microcomputer from the viewpoint of memory and calculation speed.
Therefore, while providing a simple control system that does not require the preparation of a vehicle model for each vehicle, the smooth acceleration feeling in which the front-rear G is suppressed even when there is a change in the road surface μ, etc., and good acceleration performance Coexistence can be achieved.
  In addition, in the driving wheel speed servo calculation means, the driving wheel torque is not controlled by the driving wheel speed servo calculation immediately after the traction control operation, and the driving torque is controlled based on the driving slip after the driving wheel slip occurs. After waiting for the convergence of the drive wheel slip by the control, the drive wheel torque is controlled by the drive wheel speed servo calculation.
That is, if the drive wheel torque is controlled by the drive wheel speed servo calculation immediately after the traction control operation, the servo works to suppress the slip, resulting in a longer time for closing the throttle, and the acceleration timing after the slip recovery is increased. Slow (see FIG. 7).
On the other hand, it is possible to prevent the acceleration timing from being delayed by controlling the drive wheel torque by the drive wheel speed servo calculation after the drive wheel slip is settled (see FIG. 6).
[0018]
  Claim 2In the described invention, from immediately after the traction control operation until the drive wheel speed servo calculation is performed,Based on the throttle command value based on the drive wheel slip amount, the throttle command value based on the drive wheel acceleration, the throttle command value based on the non-drive wheel acceleration, the throttle command value based on the vehicle speed, and the elapsed time from the start of the traction control operation The throttle command value is determined by select low with the throttle command value.Control by the throttle control means is performed.
Therefore,The larger the value of each of the driving wheel slip amount, driving wheel acceleration, and non-driving wheel acceleration, the smaller the throttle command value, the higher the vehicle speed, the larger the throttle command value, and the elapsed time from the start of traction control operation. By making the throttle command value smaller as it is longer, it is possible to achieve both prevention of acceleration deterioration due to excessive closing of the throttle valve and prevention of stability deterioration due to excessive slip (see FIG. 10)..
[0020]
  Claim 3In the described invention, when the accelerator opening degree by the driver operation and the throttle opening degree by the actuator operation become equal during the traction control and the driving wheel speed servo calculation, the first control end means When the two become equal, the traction control operation is terminated and simultaneously the driving wheel speed servo calculation is terminated.
In other words, when the driver returns the accelerator or when the throttle valve opens to the accelerator opening, that is, when the traction control is not necessary, when the accelerator opening equals the throttle opening. Both the traction control means and the driving wheel speed servo calculation are terminated (see FIGS. 8 and 11).
Therefore, there is no fluctuation of the driving force at the end of the traction control, and it is possible to shift from the travel by the traction control to the normal travel by the driver's accelerator operation without a sense of incompatibility.
[0021]
  Claim 4In the described invention, if the deviation between the drive wheel speed and the non-drive wheel speed is within the set value during the traction control and the drive wheel speed servo calculation, the second control end means When the set time elapses, the driving wheel speed servo calculation is terminated. Thereafter, the throttle valve is slowly opened to the accelerator opening, and the traction control is terminated when the throttle opening becomes equal to the accelerator opening.
In other words, if the drive wheel slip remains small, such as when changing from low μ to high μ, first stop the drive wheel speed servo calculation, and slowly open the throttle valve to the accelerator opening to prevent insufficient acceleration. Can do.
In addition, by terminating the traction control means when the throttle opening and the accelerator opening are equal, it becomes possible to prevent a sudden change in the throttle, preventing a sudden change in the throttle and a driver's feeling. Control can be realized (see FIG. 9).
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a configuration diagram illustrating a vehicle motion control apparatus according to the first embodiment.
[0023]
Reference numeral 1 denotes a wheel speed sensor that detects the wheel speed for each wheel, and 2 denotes an electronic throttle actuator that is driven by a motor. For example, the motor is controlled by a PWM signal from a controller to open and close the throttle. 3 is an accelerator opening sensor for detecting the accelerator opening operated by the driver, and 4 is a throttle opening sensor for detecting the throttle opening. A brake booster 5 for automatic braking can generate a brake pressure regardless of the operation of the driver by controlling the engine load with a solenoid valve. A brake pressure sensor 6 detects a master cylinder pressure. An ABS actuator 7 controls the brake pressure of each wheel cylinder by a command signal from the controller. Reference numeral 8 denotes an A / T controller for controlling the transmission gear ratio. 9 is a traction controller, which receives a signal from the wheel speed sensor 1, judges the slip state of the driving wheel from the signal, sets the target driving wheel speed according to each case, and achieves the target driving wheel speed. Thus, the electronic throttle actuator 2, the brake booster 5 and the ABS actuator 7 are operated.
[0024]
Next, the operation will be described.
[0025]
[Traction control processing]
FIG. 2 is a flowchart showing the arithmetic processing of the traction controller 9 in the first embodiment. Hereinafter, description will be given based on this flowchart.
[0026]
In step 1, the accelerator opening signal APO from the accelerator opening sensor 3, the throttle opening signal TVO from the throttle opening sensor 4, the driving wheel speed signal Vw_d and the non-driving wheel speed Vw_f from the wheel speed sensor 1, the brake pressure The master cylinder pressure MCP is read from the sensor 6 and the current gear ratio GP is read from the A / T controller 8.
[0027]
In step 2, it is determined whether or not traction control is being performed based on the state of the TCS flag. If the traction control is being performed, the process proceeds to step 9; if not, the process proceeds to step 3.
[0028]
In step 3, if the driving wheel acceleration Vwd_d is larger than the threshold value S1, the process proceeds to step 4; otherwise, the process proceeds to step 5.
[0029]
In step 4, it is determined whether or not the difference between the drive wheel speed Vw_d and the non-drive wheel speed Vw_f is larger than the threshold value S2. If the difference is larger, the process proceeds to step 6;
[0030]
In step 5, since the traction control is not activated, the throttle opening command value TVO_com is set as the accelerator opening signal APO. Thereafter, the process proceeds to a throttle servo system calculation and a brake servo system calculation in step 37.
[0031]
In step 6, a traction flag is set as traction control start.
[0032]
In step 7, the First flag indicating immediately after the start of traction control is set.
[0033]
In step 8, the throttle opening command value TVO_com immediately after the start of traction control is calculated. That is, the throttle opening command value TVO_com is calculated until the first drive wheel slip is recovered after the traction control is started. In the first embodiment, as shown in FIG. 10, calculation is performed based on maps set in advance according to the elapsed time from the driving wheel slip amount, driving wheel acceleration, non-driving wheel acceleration, vehicle speed, and traction flag set. The throttle opening command value is selected low, and the throttle opening command value TVO_com is calculated. Thereafter, the process proceeds to the throttle servo system calculation and the brake servo system calculation in step 37.
[0034]
In Step 9, the state of the First flag is checked. If the First flag is set, the process proceeds to Step 10, and if it is cleared, the process proceeds to Step 15.
[0035]
In step 10, it is determined whether or not the difference between the drive wheel speed Vw_d and the non-drive wheel speed Vw_f is smaller than the threshold value S3. If the difference is smaller, the process proceeds to step 11;
[0036]
In step 11, if the driving wheel acceleration Vwd_d is smaller than the threshold value S4, it is determined that the driving wheel slip is recovered, and the process proceeds to step 12. Otherwise, the process proceeds to step 7 and step 8, and the throttle opening command value TVO_com is set. calculate. Thus, it is determined whether or not the first drive wheel slip has been recovered after the start of traction control.
[0037]
In Step 12, the First flag is cleared on the assumption that the first drive wheel slip has recovered after the start of traction control.
[0038]
In step 13, a servo flag indicating a driving wheel speed servo calculation state is set. Immediately after the start of the traction control, the traction control was performed using the throttle opening command value TVO_com calculated in step 8, but based on the throttle opening command value TVO_com and the brake pressure command value BRK_com calculated by the driving wheel speed servo calculation. Perform traction control.
[0039]
In step 14, the drive wheel speed Vw_d is set as the target drive wheel speed Vw_dcom as the target drive wheel speed Vw_dcom at the start of the drive wheel speed servo calculation.
[0040]
In step 15, the throttle opening command value TVO_com is compared with the accelerator opening signal APO. If the throttle opening command value TVO_com is small, the process proceeds to step 16; otherwise, the process proceeds to step 34.
[0041]
In step 16, the state of the servo flag is checked. If the servo flag is set, that is, if the driving wheel speed servo calculation is in progress, the process proceeds to step 17, and if clear, the process proceeds to step 30.
[0042]
In step 17, it is determined whether or not the difference between the target driving wheel speed Vw_dcom and the non-driving wheel speed Vw_f is smaller than the threshold value S5. Otherwise, go to Step 18.
[0043]
In step 18, the counter that counts the time that satisfies the condition of step 17 is cleared.
[0044]
In step 19, the target drive wheel speed Vw_dcom is calculated for the drive wheel speed servo calculation according to the flowcharts shown in FIGS.
[0045]
In step 20, it is checked whether or not the time satisfying the condition of step 17 exceeds a predetermined time T. If the counter is larger than the predetermined time T, the process proceeds to step 21; otherwise, the process proceeds to step 23.
[0046]
In step 21, it is determined that the driving wheel speed servo calculation is completed, and the servo flag is cleared.
[0047]
In step 22, counter is cleared, and the process proceeds to throttle servo system calculation in step 37.
[0048]
In step 23, counter is counted up. Thereafter, the process proceeds to step 19 to calculate the target drive wheel speed Vw_dcom.
[0049]
In step 24, it is checked whether or not the target drive wheel speed Vw_dcom exceeds the upper limit value. A value obtained by adding the predetermined value VO to the non-drive wheel speed Vw_f is the upper limit value of the target drive wheel speed Vw_dcom. If it exceeds the upper limit value, the process proceeds to step 25; otherwise, the process proceeds to step 26.
[0050]
In step 25, the target drive wheel speed Vw_dcom is set to the upper limit value (Vw_f + VO), and the process proceeds to step 26.
[0051]
In step 26, a driving wheel speed servo system calculation is performed to obtain a driving wheel torque command value TRQ_com necessary for the driving wheel speed Vw_d to coincide with the target driving wheel speed Vw_dcom (see FIG. 5).
[0052]
Here, the robust model matching control system shown in FIG. 5 will be described.
The robust model matching control system includes a robust compensator and a model matching compensator. The robust compensator is a so-called disturbance compensator, and it is possible to configure a control system that matches the actual characteristics with the linear model by estimating and correcting disturbances such as modeling errors and running resistance of the controlled object. The robust compensator is provided with a robust filter that determines the disturbance elimination performance of the robust compensator, and is composed of, for example, a low-pass filter having a steady gain of 1 and a time constant Tc. At this time, disturbance rejection performance improves if the cutoff frequency is increased, but there is a trade-off problem that the closed loop system including the robust compensator becomes unstable, and the cutoff frequency is considered in consideration of the performance of the entire system. To decide.
[0053]
The model matching compensator is a compensator for matching the response characteristics of the vehicle speed servo system to the reference model, and the input / output response characteristics are determined by the reference model of the feedforward section, and the disturbance rejection performance and stability are determined by the reference model of the feedback section. Determine sex. By designing the vehicle speed servo system using the robust model matching control method in this way, the response that follows the characteristics of the reference model against modeling errors, parameter fluctuations, disturbances, etc., and the internal variables do not diverge quickly. The convergence stability can be ensured.
[0054]
In step 27, a throttle opening command value TVO_com and a brake pressure command value BRK_com are calculated from the drive wheel torque command value TRQ_com. When the drive wheel torque command value TRQ_com is positive, the throttle opening command value TVO_com is calculated, and when it is negative, the brake pressure command value BRK_com is calculated. However, even when the drive wheel torque command value TRQ_com is negative, the brake pressure command value BRK_com remains zero as long as it can be generated by engine braking.
[0055]
In step 28, the throttle opening command value TVO_com is compared with the accelerator opening signal APO. If the throttle opening command value TVO_com is large, the process proceeds to step 29. Otherwise, the process proceeds to step 37.
[0056]
In step 29, the maximum value of the throttle opening command value TVO_com is set as the accelerator opening signal APO. The maximum value of the throttle opening command value TVO_com is set as the accelerator opening signal APO by the operations of Step 28 and Step 29. Thereafter, the process proceeds to the throttle servo system calculation in step 37.
[0057]
In step 30, it is determined whether or not the drive wheel acceleration Vwd_d is larger than the threshold value S6. If it is larger, the process proceeds to step 31. Otherwise, the process proceeds to step 32.
[0058]
In step 31, it is determined whether or not the difference between the drive wheel speed Vw_d and the non-drive wheel speed Vw_f is greater than the threshold value S7. If so, the process proceeds to step 13 as the drive wheel speed servo calculation start, and the servo flag is set. . Otherwise, go to step 32. The threshold values S6 and S7 are set to values smaller than the threshold values S1 and S2 for judging the start of traction control when the traction control is not activated (values that are easy to enter control). Drive wheel slip is prevented from becoming large when servo calculation is being performed.
[0059]
In step 32, a value obtained by adding the predetermined opening ΔTVO to the throttle opening command value TVO_com is set as a new throttle opening command value TVO_com. After determining at step 21 that the driving wheel speed servo calculation is completed, the throttle opening command value TVO_com is slowly increased to the accelerator opening signal APO.
[0060]
In step 33, it is checked whether or not the throttle opening command value TVO_com increased in step 32 exceeds the accelerator opening signal APO. When the throttle opening command value TVO_com exceeds the accelerator opening signal APO, the routine proceeds to step 35 and the traction control is terminated. Otherwise, the operation proceeds to the throttle servo system calculation in step 37.
[0061]
In step 34, since the throttle opening command value TVO_com is larger than the accelerator opening signal APO, the traction control is terminated. First, the servo flag is cleared and the routine proceeds to step 35.
[0062]
In step 35, the throttle opening command value TVO_com is used as the accelerator opening signal APO.
[0063]
In step 36, the TCS flag is cleared, and the process proceeds to throttle servo system calculation and brake servo system calculation in step 37.
[0064]
In step 37, based on the throttle opening command value TVO_com and the brake pressure command value BRK_com, a throttle servo system calculation and a brake pressure servo system calculation are performed. In the throttle servo system calculation, a drive signal to the electronic throttle actuator 2 is calculated such that the throttle opening signal TVO from the throttle opening sensor 4 matches the throttle opening command value TVO_com. In the brake pressure servo system calculation, the drive signal to the brake booster 5 is calculated so that the master cylinder pressure MCP from the brake pressure sensor 6 matches the brake pressure command value BRK_com, and the brake pressure is generated only on the drive wheels. Then, a drive signal to the ABS actuator is calculated.
[0065]
[Target drive wheel speed calculation]
FIG. 3 shows a flowchart for calculating the target drive wheel speed Vw_dcom.
[0066]
In step 101, a value α that determines the inclination of the target drive wheel speed Vw_dcom that changes during traction control is calculated according to the flowchart shown in FIG.
[0067]
In step 102, it is determined whether or not the drive wheel speed Vw_d is larger than the target drive wheel speed Vw_dcom. If it is larger, the process proceeds to step 103, and otherwise, the process proceeds to step 111.
[0068]
In step 103, the hold END flag is checked. If cleared, the process proceeds to step 104. If set, the process proceeds to step 107. Here, the hold END flag is a flag that is set when the fixed state of the target drive wheel speed Vw_dcom is released.
[0069]
In step 104, the hold flag is checked. If it is cleared, the process proceeds to step 109. If it is set, the process proceeds to step 105.
[0070]
In step 105, it is determined whether or not the difference between the target driving wheel speed Vw_dcom and the non-driving wheel speed Vw_f is smaller than the threshold value S5. Otherwise, go to step 109.
[0071]
In step 106, a hold END flag indicating that the fixed state of the target drive wheel speed Vw_dcom has been released is set.
[0072]
In step 107, the fixed state of the target drive wheel speed Vw_dcom is released and increased. The increase amount is a value obtained by adding α obtained in step 101 to the change amount of the non-drive wheel speed Vw_f, and a value obtained by adding this value to the previous target drive wheel speed Vw_dcom (-1) is a new target drive wheel speed. Vw_dcom.
[0073]
In step 108, the hold flag indicating the fixed state of the target drive wheel speed Vw_dcom is cleared.
[0074]
In step 109, the target drive wheel speed Vw_dcom is set to the previous target drive wheel speed Vw_dcom (-1). That is, the target drive wheel speed is fixed.
[0075]
In step 110, a hold flag indicating a fixed state of the target drive wheel speed Vw_dcom is set.
That is, the target driving wheel speed Vw_dcom when the driving wheel speed Vw_d is larger than the target driving wheel speed Vw_dcom is calculated by the operations of Step 103 to Step 110. Basically, the target drive wheel speed Vw_dcom is in a fixed state, but if it is determined in step 105 that the difference between the target drive wheel speed Vw_dcom and the non-drive wheel speed Vw_f is smaller than the threshold value S5, the target drive wheel speed Vw_dcom Release and increase the fixed state. For example, the state where the non-drive wheel speed Vw_f cannot follow the target drive wheel speed Vw_dcom is a state where the acceleration limit on the road surface at that time is exceeded, and the slip of the drive wheel increases. When the deviation between the non-drive wheel speed Vw_f and the target drive wheel speed Vw_dcom falls within the predetermined value, the target drive wheel speed Vw_dcom can be set close to the acceleration limit according to the road surface by accelerating the target drive wheel speed Vw_dcom again. This enables efficient acceleration while suppressing slippage of the drive wheel.
[0076]
In step 111, the hold flag is checked. If it is cleared, the process proceeds to step 116. If it is set, the process proceeds to step 112.
[0077]
In step 112, it is determined whether or not the difference between the target drive wheel speed Vw_dcom and the non-drive wheel speed Vw_f is smaller than the threshold value S5, and the difference between the target drive wheel speed Vw_dcom and the non-drive wheel speed Vw_f is the threshold value S5. If it is smaller, the process proceeds to step 117, otherwise the process proceeds to step 113.
[0078]
In step 113, when the drive wheel speed Vw_d is equal to the non-drive wheel speed Vw_f, the slip of the drive wheel is recovered even if the difference between the target drive wheel speed Vw_dcom and the non-drive wheel speed Vw_f is greater than the threshold value S5. The process proceeds to step 117 and otherwise proceeds to step 114.
In other words, the target drive wheel speed Vw_dcom is fixed even when the drive wheel speed slips and recovers to the non-drive wheel speed Vw_f before the deviation between the non-drive wheel speed Vw_f and the target drive wheel speed Vw_dcom falls within the predetermined value. By canceling and accelerating the target drive wheel speed Vw_dcom, it is possible to prevent a delay in the acceleration timing.
[0079]
In step 114, since the slip of the drive wheel is still large, the target drive wheel speed Vw_dcom is set to the previous target drive wheel speed Vw_dcom (-1). That is, the target aerodynamic wheel speed is fixed.
[0080]
In step 115, a hold flag indicating a fixed state of the target drive wheel speed Vw_dcom is set.
[0081]
In step 116, the hold END flag indicating that the fixed state of the target drive wheel speed Vw_dcom has been released is cleared.
[0082]
In step 117, the fixed state of the target drive wheel speed Vw_dcom is released and increased. The increase amount is a value obtained by adding α obtained in step 101 to the change amount of the non-drive wheel speed Vw_f, and a value obtained by adding this value to the previous target drive wheel speed Vw_dcom (-1) is a new target drive wheel speed. Vw_dcom.
[0083]
In step 118, the hold flag indicating the fixed state of the target drive wheel speed Vw_dcom is cleared.
That is, the target driving wheel speed Vw_dcom when the driving wheel speed Vw_d is smaller than the target driving wheel speed Vw_dcom is calculated by the operations of Steps 111 to 118. Basically, the target drive wheel speed Vw_dcom is accelerated by a value obtained by adding α obtained in step 101 to the amount of change in the non-drive wheel speed Vw_f, but there is a difference between the target drive wheel speed Vw_dcom and the non-drive wheel speed Vw_f. When it is larger than the threshold value S5 and the driving wheel speed Vw_d is larger than the non-driving wheel speed Vw_f, the fixed state of the target driving wheel speed Vw_dcom is continued.
[Calculation of α]
FIG. 4 is a flowchart showing the α calculation process.
[0084]
In step 1501, the target driving wheel speed Vw_dcom is compared with the driving wheel speed Vw_d. If the target driving wheel speed Vw_dcom is large, the process proceeds to step 1502, and otherwise, the process proceeds to step 1514.
[0085]
In step 1502, it is determined whether or not the maximum driving wheel acceleration Vwd_d_max is smaller than the driving wheel acceleration Vwd_d. When the driving wheel acceleration Vwd_d is smaller, the process proceeds to step 1503.
[0086]
In step 1503, the maximum drive wheel acceleration Vwd_d_max is set as the drive wheel acceleration Vwd_d, and the process proceeds to step 1504.
[0087]
In step 1504, it is determined whether or not the drive wheel acceleration Vwd_d is larger than the threshold value S6. If it is larger, the process proceeds to step 1505, and if smaller, the process proceeds to step 1508.
[0088]
In step 1505, the state of the α corrected flag indicating whether α has been corrected is checked. If the α corrected flag is set, the process proceeds to step 1518. If the α corrected flag is not set, the process proceeds to step 1506. move on.
[0089]
In step 1506, the correction amount β is subtracted from α, and the process proceeds to step 1507.
[0090]
In step 1507, the α corrected flag is set.
That is, when α is large, the driving wheel speed Vw_d fluctuates in a vibrational manner. Therefore, in the operations of steps 1504 to 1506, when the target driving wheel speed Vw_dcom becomes too large and exceeds the maximum driving force, α can be set small, and the driving wheel speed Vw_d fluctuates in a vibrational manner. Can be prevented.
[0091]
In step 1508, the α corrected flag is cleared.
[0092]
In step 1509, it is determined whether or not the driving wheel acceleration Vwd_d is smaller than the threshold value S7. If it is smaller, the process proceeds to step 1510. If it is larger, the process proceeds to step 1512.
[0093]
In step 1510, the duration of the state where the drive wheel acceleration Vwd_d is smaller than the threshold value S7 is checked. If the duration counter value Timer is larger than the predetermined time T1, the process proceeds to step 1511. Otherwise, the process proceeds to step 1513.
[0094]
In step 1511, the correction amount β is added to α. Thereby, the inclination of the target drive wheel speed Vw_dmax can be increased. That is, if the target drive wheel speed Vw_d is low for a predetermined time, the acceleration performance is poor. However, when the driving wheel acceleration Vwd_d continues for a predetermined time, it is possible to increase the target driving wheel speed Vw_dcom by increasing α, thereby improving the acceleration performance.
[0095]
In step 1512, the duration counter value Timer is cleared.
[0096]
In step 1513, the duration counter value Timer is counted up.
[0097]
In step 1514, α is calculated from the map based on the maximum driving wheel acceleration Vwd_d_max obtained in step 1502 and step 1503. That is, this α is reflected as the value of α set when the fixation of the target drive wheel speed Vwd_d_max is released next time. As the maximum driving wheel acceleration Vwd_d_max is larger, α is set to be smaller, and as the maximum driving wheel acceleration Vwd_d_max is smaller, α is set to be larger. Therefore, even when the target driving wheel speed Vw_dcom becomes too large and exceeds the maximum driving force, α Can be set small, and the divergence tendency of the drive wheel speed Vw_d can be suppressed. In addition, when the target drive wheel speed Vw_dcom is small and acceleration is poor, α can be set large and acceleration can be improved.
[0098]
In step 1515, the maximum drive wheel acceleration Vwd_d_max is cleared.
[0099]
In step 1516, the α corrected flag is cleared.
[0100]
In step 1517, the duration counter value Timer is cleared.
[0101]
In step 1518, the road surface μ is determined. As a method of determining the road surface μ, for example, by comparing the deviation S_err between the slip ratio Sd of the drive wheel and the slip ratio Sf of the non-drive wheel and the slip ratio deviation S_err_mdl corresponding to the high μ road calculated from the vehicle model. The road surface μ may be estimated.
[0102]
In step 1519, an α correction coefficient γ is calculated from the map based on the road surface μ. γ is 0 ≦ γ ≦ 1.0, and in the case of a high μ road, γ = 1.0.
[0103]
In step 1520, α × γ is calculated to calculate a new α. In other words, α corresponding to the road surface μ can be set by the operation from step 1518 to step 1520, so that the target drive wheel speed Vw_dcom at which the maximum driving force can be obtained earlier can be set. In the first embodiment, the road surface μ is continuously determined and α is corrected. However, the three-step μ determination such as high μ, medium μ, and low μ, and high μ and low μ are performed. The same effect can be obtained even in such a two-step μ discrimination.
[0104]
As described above, in the vehicle motion control apparatus according to the first embodiment, as shown in the time chart of FIG. 11, since the driving wheel speed servo calculation is performed only when the traction control is activated, the traction control is not activated. There is no need to prepare a vehicle model for driving wheel speed servo calculation. Therefore, the cost of creating a vehicle model can be reduced. Further, when a system is configured using an in-vehicle microcomputer, the amount of program is reduced, so that control calculation can be performed with a cheaper microcomputer from the viewpoint of memory and calculation speed.
[0105]
In addition, as shown in FIG. 7, when the driving wheel speed servo calculation is performed immediately after the traction control operation, the servo works to suppress the slip, resulting in a longer time for closing the throttle, and the acceleration timing after slip recovery. Becomes slower. However, as shown in FIG. 6, the acceleration timing can be prevented from being delayed by performing the drive wheel speed servo calculation after the drive wheel slip is settled in Step 7 to Step 14.
[0106]
Further, as shown in the time chart of FIG. 8, when the driver returns the accelerator or when the throttle opens to the accelerator opening, the traction control and the driving wheel speed servo calculation are finished, and the accelerator opening APO And the throttle opening TVO are made equal (corresponding to step 15 to step 18).
[0107]
Also, as shown in the time chart of FIG. 9, when the driving wheel slip continues to be small, such as when changing from low μ to high μ, the driving wheel speed servo calculation is first terminated and the throttle is slowly opened to the accelerator opening. (Corresponding to step 30 to step 32), it is possible to prevent insufficient acceleration. Further, when the throttle opening becomes equal to the accelerator opening, the traction control means is terminated (corresponding to steps 35 to 36), so that it becomes possible to prevent a sudden change in throttle, In addition to preventing, it is possible to realize control suitable for the driver.
[0108]
(Other embodiments)
As described above, the first embodiment has been described, but any design change or the like within a range not departing from the gist of the present invention is included in the present invention.
[0109]
For example, as shown in FIG. 5, in this embodiment, robust model matching control, which is employed in a vehicle speed servo system such as a vehicle automobile speed control device, is used in a drive wheel speed servo system, but PI control or the like The same effect can be obtained even when the servo system is configured using the. In this case, the PI control gain or the like is changed instead of the control constant of the robust compensator.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram illustrating a vehicle motion control device according to an embodiment.
FIG. 2 is a flowchart showing the processing contents of a traction controller in the first embodiment.
FIG. 3 is a flowchart showing a calculation process for calculating a target drive wheel speed in the first embodiment.
FIG. 4 is a flowchart illustrating a calculation process for calculating a predetermined amount α in the first embodiment.
FIG. 5 is a configuration diagram showing a configuration of a driving wheel speed servo system in the first embodiment.
6 is a time chart when driving wheel speed servo calculation is started after driving wheel slip has settled in Embodiment 1. FIG.
FIG. 7 is a time chart when driving wheel speed servo calculation is started simultaneously with the traction control operation in the first embodiment.
FIG. 8 is a time chart showing driving wheel speed servo calculation and traction control end timing in the first embodiment.
FIG. 9 is a time chart showing driving wheel speed servo computation and traction control end timing in the first embodiment.
FIG. 10 is a time chart of traction control, drive wheel speed servo calculation, drive wheel speed, target drive wheel speed, non-drive wheel speed, accelerator opening, and throttle opening in the first embodiment.
FIG. 11 is a diagram showing a throttle opening command value calculation method immediately after the start of traction control in the first embodiment.
[Explanation of symbols]
1 Wheel speed sensor
2 Electronic throttle actuator
3 Accelerator position sensor
4 Throttle opening sensor
5 Brake booster
6 Brake pressure sensor
7 Actuator
8 Controller
9 Traction controller

Claims (4)

In a vehicle motion control device including traction control means for controlling drive wheel torque based on a slip ratio of a drive wheel by at least one of throttle control and brake control,
Traction control operation state determining means for determining whether the traction control is operating or when the traction control is not operating;
Traveling state detecting means for detecting the traveling state of the vehicle;
Target drive wheel speed calculating means for calculating the target drive wheel speed based on the running state detection value;
Driving wheel speed detecting means for detecting the driving wheel speed of the vehicle;
Drive wheel speed servo calculation means for controlling the drive wheel torque by servo calculation that eliminates the deviation between the target drive wheel speed calculation value and the drive wheel speed detection value only at the time of traction control operation , and
The drive wheel speed servo calculation means does not control the drive wheel torque by the drive wheel speed servo calculation immediately after the traction control operation, and generates the drive wheel torque based on the slip ratio of the drive wheel after the drive wheel slip occurs. A vehicle motion control device that controls driving wheel torque by driving wheel speed servo calculation after waiting for convergence of driving wheel slip by traction control to be controlled. . The vehicle motion control device according to claim 1,
Between the time immediately after the traction control operation and the drive wheel speed servo calculation, the throttle command value based on the drive wheel slip amount, the throttle command value based on the drive wheel acceleration, the throttle command value based on the non-drive wheel acceleration, A vehicle motion control device that performs control by a throttle control means that determines a throttle command value by a select low of a throttle command value based on a vehicle speed and a throttle command value based on an elapsed time from the start of traction control operation . The vehicle motion control device according to claim 1 or 2,
If the accelerator opening by the driver's operation and the throttle opening by the actuator operation are equal during the traction control and driving wheel speed servo calculation, the traction control operation is terminated at the same time when both opening positions are equal, and the drive A vehicle motion control device comprising first control ending means for ending wheel speed servo calculation. The vehicle motion control device according to any one of claims 1 to 3,
During driving wheel speed servo calculation during traction control, if the deviation between the driving wheel speed and the non-driving wheel speed remains within the set value for a set time, the drive wheel speed servo calculation is terminated when the set time elapses, Thereafter, the vehicle motion control device is provided with second control end means for slowly opening the throttle valve to the accelerator opening, and ending the traction control when the throttle opening becomes equal to the accelerator opening.

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