JPH04183943A - Acceleration slip control device - Google Patents

Abstract

PURPOSE:To prevent control by means of value of mu different from an actual road surface condition by calculating friction coefficient of the road surface from vehicle acceleration, and prohibiting the use of the calculated friction coefficient of the road surface for control while travelling on a sloping road in the case of carrying out slip control according to its magnitude. CONSTITUTION:An acceleration slip control device has a slip detecting means A to detect slip volume of a driving wheel, and also has a friction coefficient renewing means C. The friction coefficient renewing means C calculates friction coefficient muof the road surface by using vehicle acceleration detected by means of an acceleration detecting means B, vehicle weight W and a driving wheel load Wr, and in the case the calculated friction coefficient is different from the value mu using at present for control, it inputs new value mu obtained by renewing the value mu to a control means D. The control means D carries out driving torque control according to the renewed value mu and the slip volume. In this case, a sloping road detecting means E to detect sloping road travel is arranged, and when the fact that the vehicle is now travelling on a sloping road is detected, renewal of the friction coefficient of the road surface by means of the friction coefficient renewing means C is prohibited by means of a prohibiting means F.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an acceleration slip control device that prevents excessive slip from occurring in drive wheels when a vehicle starts or accelerates.

[Conventional technology]

2. Description of the Related Art Acceleration slip control devices are generally known that prevent excessive slip of drive wheels when a vehicle starts or accelerates, thereby achieving a balance between straight-line stability and acceleration performance of the vehicle.

These acceleration slip control devices set a target drive wheel rotation speed of the vehicle, and adjust the drive I/I so that the slip amount, defined as the difference between this target value and the actual drive wheel rotation speed, is within a predetermined value. Feedback control of torque is performed. In these controls, the responsiveness and stability of the control are improved by changing the rate of change of the drive torque in accordance with the magnitude of the road surface friction coefficient μ.

For example, if the value of μ is small (road surface that is easy to slip), μ
Compared to the case where the value of μ is large, by setting the change speed smaller on the drive torque increase side, hunting is prevented and control stability is improved, and when the value of μ is large, the drive torque increase speed is reduced. Controls that can be set to improve responsiveness are known.

An example of this type of acceleration slip control device is JP-A-60
There is an apparatus described in Japanese Patent No.-99757. The device disclosed in the same publication calculates the road surface friction coefficient μ from the acceleration obtained from the differential value of the driven wheel speed when driving wheel slip occurs, and depending on the value of μ, when controlling the drive torque by cutting fuel etc. The torque value increase/decrease is set.

[Problem to be solved by the invention]

In the device disclosed in Japanese Patent Application Laid-Open No. 60-99757, the vehicle body acceleration is determined from the change in driven wheel speed when a slip occurs, and this acceleration is used to estimate the road surface friction coefficient.

In other words, when the vehicle acceleration is A and the vehicle weight is W, the driving force F required to accelerate the vehicle body is calculated as F--A (g
is the gravitational acceleration). On the other hand, this driving force F is determined by the frictional force between the driving wheels and the road surface, and can be expressed as F-μ·Wr using the load Wr applied to the driving wheels and the road surface friction coefficient. From these two equations, the road friction coefficient μ is μ−W/
It is calculated as W r ·g×A.

The method of calculating the road surface friction coefficient from the vehicle acceleration as described above has good accuracy on flat roads (the friction coefficient can be estimated, but when driving on a slope, the calculation of the friction coefficient may become inaccurate. In other words, the above method While it is assumed that the driving force applied to the vehicle body is a force given by the drive wheels, when driving downhill, gravity is added to the driving force of the vehicle body.Therefore, in the above method, when driving downhill, gravity is acts in a direction that accelerates the vehicle, so the road surface friction coefficient is calculated to be larger than it actually is.When driving uphill, gravity acts in a direction that decelerates the vehicle, so the road surface friction coefficient is calculated to be smaller than it actually is.

If control is performed using a large friction coefficient value even though the actual road surface friction coefficient is small, the control will progress in the direction of increasing the drive torque, increasing slip and making it difficult to converge to the control target. A problem arises in which stability is reduced. On the other hand, if control is performed using a small friction coefficient value even though the actual friction coefficient is large, there is a problem in that the control progresses in the direction of decreasing drive torque, resulting in a decrease in control responsiveness and acceleration. .

In view of the problem described in item 2, the present invention provides that when performing acceleration pickpocket knob control using the road surface friction coefficient calculated from the vehicle body acceleration, the road surface friction coefficient calculated from the vehicle body acceleration is used for control while driving on a slope. The object of the present invention is to provide an acceleration slip control device that can prevent the deterioration of stability and acceleration caused by.

[Means for solving the problem] According to the present invention, as shown in the configuration diagram of the invention in FIG.
slip detection means A for detecting the amount of slip of the driving wheels;
an acceleration detecting means B for detecting vehicle body running acceleration; a friction coefficient updating means C for calculating a road surface friction coefficient from the detected running acceleration and updating a road surface friction coefficient value used for control; and an amount of slip of the driving wheels and the road surface. In the acceleration slip door control device equipped with a control means 7 for controlling the driving force according to the friction coefficient, a slope detection means E for detecting running on a slope.
An acceleration slip control device is provided, comprising: and a prohibiting means F that prohibits the friction coefficient updating means from updating the road surface friction coefficient when it is detected that the vehicle is traveling on a slope.

(Function) The friction coefficient updating means C calculates the road surface friction coefficient μ using the vehicle body acceleration detected by the acceleration detection means B, the vehicle weight W, and the driving wheel load Wr, and updates the coefficient μ currently used for control. If it is different from the value, the value of μ is updated and the newly obtained value of μ is input to one control means.The control means uses the updated value of μ′ and the slip detected by the slip detection means A. Drive torque control is performed based on the amount.

The prohibition means F prohibits the road surface friction updating means C from updating the value of μ when the slope detection means detects that the vehicle is traveling on a slope.

[Embodiment 1] FIG. 2 shows a configuration diagram of an acceleration slip control device of the present invention. In the figure, 1 indicates a vehicle, 10 indicates an engine mounted on the vehicle 1, 3a and 3b drive wheels driven from the vehicle engine via a gear box 5, and 4a and 4b indicate driven wheels. The driving wheels 3a, 3b and the driven wheels 4a, 4b each have a wheel speed sensor 22a, which detects the rotational speed of the wheel.
22b, 24a.

24b is provided.

In this embodiment, the intake passage of the engine 10 includes a main throttle valve 14 that opens and closes the intake passage in response to the driver's operation of the accelerator pedal 12.
An independent sub-scott valve 16 driven by an actuator such as a step motor 18 is provided on the two-liquid side. Reference numeral 30 denotes a fuel injection control circuit (hereinafter referred to as "rEFI unit") consisting of a digital computer that controls fuel injection and ignition timing of the engine 10. In order to execute these basic controls, the EF unit receives the engine speed from the engine speed sensor 32, the main throttle valve opening from the main throttle 1 sensor degree sensor 34, and the main throttle valve opening from the sub scooter sensor 36.
In addition to inputting the sub-throttle valve opening degrees from the respective input terminals, other parameters necessary for engine control are inputted from sensors (not shown). Further, the EFI unit 1- is connected to a fuel injection valve 38 and a spark plug 40 of the engine 10, and controls the fuel injection amount and ignition timing, respectively.

Furthermore, the reference numeral 50 indicates an acceleration slip control circuit (hereinafter referred to as rTRC unit) that performs acceleration slip control according to the present invention.
). The TRC unit 1- consists of a digital computer and the aforementioned wheel speed sensors 22a, 22b for acceleration slip control.

Each wheel speed is input from 24a and 24b, the engine rotation speed is input from an engine rotation speed sensor 32, and the opening degrees of the main throttle valve 14 and sub throttle valve 16 are input from throttle valve opening sensors 34 and 36, respectively. It is connected to the step motor of the throttle valve 16 and controls the opening degree of the sub-throttle valve. Further, reference numeral 52 in the figure indicates an acceleration sensor attached to the vehicle body, which detects vehicle body acceleration and inputs it to the TRC units I-50. The acceleration sensor 52 is of a type that linearly detects the displacement of a weight attached to a beam whose both ends are fixed as distortion of the beam. FIG. 10 shows the principle of operation of the acceleration sensor 52. The strain gauges 52a and 52b are connected to the beam 52. so that the displacement due to the acceleration of the weight 52c can be detected with high accuracy. They are arranged symmetrically at the position where the distortion of d is maximum, and by forming a bridge, the detection accuracy is increased and the influence on the output due to behavior in non-detection directions such as the vertical direction is eliminated.

TRC unit 50 is connected to EFI unit 30,
A twin cut 1 signal, which will be described later, is output to the EFI unit 30 to cause the EFI unit 30 to execute the twin cut.

In this embodiment, drive torque control during acceleration slip control is performed by PID controlling the opening degree of the sub-throttle valve 16 based on the drive wheel slip amount, and as described later, the drive torque control is performed according to the value of the road surface friction coefficient μ. The opening gain of the sub-throttle valve 15 is changed with respect to the amount of slip.

The road surface friction coefficient μ is obtained, for example, as follows.

In other words, when the acceleration slip control is being executed and the driving wheel slip is controlled within a predetermined value, the time period for the driven wheel speed to increase by a predetermined amount b km/h is determined, and the acceleration during this period is A=b/l. Calculate. As described above, the road surface friction coefficient μ is obtained as μ-W/Wr-gXA using this acceleration A, vehicle weight W, and driving wheel load Wr.

As mentioned above, the road surface friction coefficient μ obtained from the above matches the actual road surface friction coefficient on a flat road, but when driving on a slope, it is affected by gravity and may have a value different from the actual road surface friction coefficient. In the present invention, the acceleration □degree sensor 52
The acceleration G detected by the above is compared with the acceleration A determined from the driven wheel speed to determine whether the vehicle is currently running on a slope.

In other words, if the difference between the acceleration G detected by the acceleration sensor and the acceleration A found from the driven wheel speed is greater than a predetermined value, that is, if l(, -AI>D(: set value) holds true, then the current running is on a slope. The road surface N friction coefficient μ calculated from the acceleration A is not used for control, but the previous μ value is used for control.In this way, when driving on a slope, the value of μ By not changing .mu., it is possible to prevent control from being performed using a value of .mu. that differs from the actual road surface condition.

The slope running determination and control operation for updating the value of μ according to the present invention will be explained below with reference to FIGS. 3 to 5.

FIG. 3 is a flowchart showing the slope running determination operation. This routine is executed by the TRC unit as a time interrupt routine.

In FIG. 3, step 90 shows the calculation operation of the vehicle body acceleration MR. In this routine, the vehicle acceleration is determined by using the difference between the driven wheel speed VR at the time of the current routine execution and the driven wheel speed VR (.-1) at the previous routine execution, and the routine execution period T. VR-(VR+h+= ■□,,-1))/To
It is required as. Next, in step 92, the acceleration deviation determined above is compared with the output G of the acceleration sensor 52 attached to the vehicle body. If the absolute value of the difference between the acceleration sensor output G and the calculated acceleration or 7 is larger than a predetermined value, it is determined that the vehicle is traveling on a slope, and a flag FP indicating that the vehicle is traveling on a slope is set to 1 (step 94 ), and if the difference between the two is within D, it is determined that the vehicle is running on a flat road, and the process proceeds to step 96, where FP is set to zero and the routine is terminated.

Next, FIG. 4 shows a calculation routine for the road surface friction coefficient μ. This routine is also executed as a time interrupt routine of the TRC unit.

Calculation of μ: ■Acceleration slip control is being executed.

(The value of the flag FSO described later is 1) (Step 200), and ■Initial Tuning] is completed (The value of the flag FSLP described later is 1)
(Step 202) ■Vehicle speed■7 is greater than or equal to a km/h (Step 204) (In this example, a=3
km/h) and furthermore, the vehicle is not currently running on a slope (the aforementioned flag FP is not 1) (step 205), and the vehicle travels bkm/h (b-1, 25).
km/h)) by measuring the time required to accelerate (CALPH). (Step 210゜2
12). As mentioned above, the road surface μ is μmW/g-WrXA
(W: vehicle weight, Wr: driving wheel acceleration, g: gravitational acceleration, A: vehicle acceleration), so if it takes T seconds to accelerate bkm/h, A = 5b/T. μmKt, /T (K5, 6: constant), which is obtained by measuring CALP)I above. In this embodiment, the value of μ itself is not determined, and the determination of classifying the magnitude of μ into three levels of high μ, medium μ, and low from the above CALPHO value is not performed (steps 212 to 218).
, control is also performed in three stages.

FIG. 5 is a flowchart showing the operation for determining whether or not the level of .mu. currently used for control is updated to the level of .mu. found in the routine of FIG.

This routine is executed after the routine of FIG. 4 as a time interrupt routine of the TRC unit I.

At step 250 in FIG. 5, it is determined whether the level of μ determined in the routine of FIG. 4 has changed from the level of μ currently used for control. 4r19) In the routine shown in the figure, if the level is not calculated when driving on a slope, etc., or if the calculated μ level has not changed from the one currently in use, terminate the routine without updating μ. .

If μ has changed, the process advances to step 252, where it is determined whether μ has shifted to the high μ side or low μ side, and the drive wheel slip 8■ and predetermined values E and F are set depending on each case. (Step 254, Step 2)
60).

This determination is only for confirming the reliability of the calculated μ level. For example, if the road surface condition has shifted to a higher μ side than the previous time in step 252, the friction coefficient has increased, so the slip value should have decreased. Therefore, in step 254, it is determined whether the slip ΔV is less than a predetermined value E (E = 2.5 km/h in this embodiment), and if 8 is larger than E, the road surface friction coefficient μ has increased. It is unreasonable that the slip has not decreased despite this, so we do not update the value of μ immediately and proceed to step 2.
In step 56, it is determined whether or not the vehicle is traveling on a rough road. When driving on a rough road, the road surface conditions change rapidly and the slippage value fluctuates greatly. Therefore, in this case, even if the average value of μ during traveling a certain distance determined by the routine shown in Fig. 4 is increasing, it is possible that slip 8■ will momentarily take a large value.
Even if .mu. is greater than or equal to E, the process proceeds to step 258, assuming that the .mu. found this time is adopted. If the vehicle is not traveling on a rough road, the calculated value of μ is determined to be unreliable, and the routine is terminated without updating μ.

In step 258, the initial setting θ of the subthrottle valve is determined by the μ and \r adopted as described above. and the current subthrottle valve target opening θ.

Make a comparison with θ (μ, as described later, is the opening degree determined from the engine speed using a map corresponding to the level of μ adopted. In this example, the μ level is controlled in three stages, so When the road surface condition changes from low μ to high μ, the initial setting θ for low μ is used.

−μ, the ZAB throttle valve opening controlled near the initial setting θ0 for high μ. It is necessary to shift to control near μ. If this transition is performed by feedback control, which will be described later, the operation will take time and the responsiveness to changes in μ will deteriorate. Therefore, in this embodiment, when μ changes,
Feedback control is performed after the control target opening is shifted all at once to near the initial setting opening corresponding to the μ level. Step 258 is a determination as to whether or not it is necessary to shift the control target opening according to μ. If the current target opening is already larger than the target opening on the high μ side, the target opening Since there is no need to reset the coefficients α, β8 . After changing β2 to match the μ level, the routine ends. Here, the coefficient α is a proportionality constant β1 used for setting the drive wheel target speed.

β2 is a gain of sub-throttle valve opening feedback control. These will be described later. - Step 2
If the current target opening degree θ3o is smaller than the initially set opening degree on the high μ side in step 58, the process proceeds to step 264 because the target opening degree needs to be reset. In this case, in order to avoid sudden changes in control characteristics, in step 264, the opening degree θ determined from μ is
, μ, is not set as the new target opening degree, but θ. /l.

and the current target opening degree θso is set as the new target opening degree. As a result, from this opening degree, β on the high μ side is
4. Feedback control using β2 is performed.

If it is determined in step 252 that there is a shift to the low μ side, in step 260, the slip-ramp Δ is determined as in step 254.
Judgment (2) is made, and (8) is a predetermined value F (in this embodiment, F
= 5 km/h) or more, the calculated value of μ is adopted. Next, in step 262, the necessity of setting the target opening degree is similarly determined, and the target opening degree is set to θ if the vehicle speed 3 is 5 km/h or less. is set as the target opening degree, and at speeds of 5 km/h or higher, θ, μ) and the current θ,. The target opening degree θ is an intermediate value between and. The setting point is different from that in the case of shifting to the high μ side (step 263
．． 265).

FIG. 6 shows a basic control routine for acceleration slip control.

This routine is executed as a repeating routine of the T' RC unit at fixed time intervals (12 milliseconds in this embodiment), and in the routines of FIGS. 3 to 5, β17) Performs feedback control of sub-throttle valve opening.

Step 100 in FIG. 6 shows a determination as to whether or not the acceleration slip control execution conditions are met. In this embodiment, as control execution conditions, it is determined that the main throttle opening degree θa is not fully closed and that there is no abnormality in the sensors. If either one of them occurs, acceleration slip control is not performed and step 172
Proceed to reset all flags and submelon 1-le valve opening θ. is set to θ5-X (fully open) and the routine ends.

If the control execution conditions are satisfied in step 100, speed parameters are read and calculated in steps 102 to 109. That is, in step 102, the vehicle body speed (2) is determined from the average value of the left and right driven wheel speeds VRL and VRR, and then in step 104, the drive wheel target speed (3) is set using VR.

In this example, ■ is the road surface friction coefficient μ in the routine shown in FIG.
Using the coefficient α determined from , it is given as -α·VR. V5 is set so that it is always greater than the vehicle speed and causes the drive wheels to slip to a predetermined level. α takes a larger predetermined value as the μ level increases, such as α-1.2 when high μ, α-1.1 when medium μ, α-1.05 when low μ, etc., for example. In this way, by setting α according to the value of μ, the slip of the drive wheels can be set small on slippery roads with low μ levels, improving straight-line stability.
On a road surface with a high μ level, the slip can be set relatively large to improve acceleration performance.

Note that if acceleration slip control is not performed, α is set for medium μ in step 172, which will be described later.

Step 106 shows the setting of the acceleration slip control starting speed (A8) and is expressed in the form of V7B (A) B-VS+7. γ is a constant for setting the control start speed to a predetermined value higher than the target value in order to prevent frequent control operations.
2.0km/h to 4.0km depending on vehicle speed and road surface conditions
Sera 1 is set to /h.

Step 108 shows the calculation of the driving wheel speed 9, and similarly to the driven wheels, the left and right driving wheel speeds vn+- and 2 are calculated. It is determined as the average of R. Next, in step 109, the slip amount is calculated. The slip amount ΔV is determined as the difference between the driving wheel speed (■) and the driving wheel target speed V5.

After completing the speed adjustment settings described above, the next step is to
The value of the flag FS is determined in the amplifier 110.

FS is a flag indicating whether or not acceleration slip control has already been started. When FS=O, it means that acceleration slip control has not been performed yet, so step 112 is executed.
The process then proceeds to step 100, where it is determined whether or not it is necessary to start acceleration slip control. This judgment is made by determining whether the drive wheel speed V is greater than the control start speed V7B, and Vo≦
In the case of V 7 B, slip/slump control is not necessary, so the routine proceeds to step 172, where the flag is reset and the sub-throttle valve opening degree θso is set to full open, and the routine ends.

VI in step 112]> ■ In case of A8, step 114 to step 118 to start acceleration slip control
Execute.

As will be described later, in this embodiment, feedback control of the sub-throttle valve opening is performed in steps 160 and 162, and in preparation for starting this feedback control, steps 114 to 118 and steps 132 to 156 are executed. In step 114, the flag FS is set to 1, and in step 116, the initial opening degree of the sub-throttle valve is set.

Since the ZAB throttle valve is always kept fully open in step 172 when acceleration slip control is not performed,
A relatively large movement must be made before the sub-scott valve reaches an opening at which control can begin. If this operation is performed using feedback control in steps 160 and 162, which will be described later, it will take time to reach the control start opening.
Since the responsiveness deteriorates, in this embodiment, when control is started, the sub-throttle valve opening is closed all at once to near the control start opening, and feedback control is performed from that state. The above-mentioned initial setting opening degrees of the Zabuskot 1 to 1 valves are determined according to the engine speed NE and the magnitude of the road surface friction coefficient μ. In this embodiment, the value of μ is divided into three levels: high μ, medium μ, and low μ, and the initial opening degree is set for each level of μ for each engine speed. . However, since the road surface friction coefficient shown in FIG. 4 has not yet been calculated in step 116, the control start opening degree is calculated from the engine speed using a map of the initial setting opening degree θ (Mμ) of medium μ, and the control start degree is calculated from the engine rotation speed. It is set as the target opening degree θso.

In addition, as for the initial setting θ(p), the higher the rotation speed, the larger the opening degree becomes, and at the same rotation speed, the larger μ becomes, the larger the opening degree becomes.

In step 116, the initial target opening degree θ. When is set,
The steamer motor 18 of the Zabu throttle valve 16 drives the Zabu throttle valve 16 so that the opening degree is the target.

After the initial target opening degree θ3o is set, the initial twin cut execution flag I'CUT is set to 1 in step 118.
is set and the routine ends.

The initial power cut is a power cut that is performed only once to lower the engine speed immediately after the start of the acceleration slip control, and the flag FCI is set at the same time as the start of the acceleration slip control.
When JT is set to 1, EFJ for engine control is activated.
The unit executes Tsuyuniruka j-. Tunnel cuts are performed until flag FCUT is reset to zero.

If FS=1 holds true in step 110, it means that steps 112 to 118 have been completed during the previous routine execution, so in this case, proceed to step 120, and check if flag FCUT=1 holds true. It is determined whether or not. If the initial twin cut started in step 118 is continuing, FCUT=1, and the process then proceeds to step 132, where it is determined whether the initial twin cut end condition is satisfied. The initial twin cut 1- ends when the engine speed increase speed ΔNB becomes less than a predetermined value (for example, -1000 rpm/sec), that is, when it is detected that the effect of the initial twin cut has appeared and the engine speed increase has slowed down. do. If the determination in step 132 is negative, step 1
At 34° 136, the slip amount Δ■ is integrated and the number of integrations is counted up, and the process proceeds to step 160. If an affirmative determination is made in step 132, the flag FCUT is reset to zero in step 138 to complete the initial twin cut, and then in step 140, the slip amount average value 3] is calculated from the slip amount accumulated in step 134, and step At 142, a flag FSLP is set to 1 to indicate that the initial twin cut and SLP calculations are complete.

Steps 144 to 156 show the operation of resetting the initial target opening degree θso using the slip amount average value obtained above. As mentioned above, θ3o set in step 116 is temporarily calculated using a map for medium μ, and may not correspond to the actual road surface condition. Therefore, in this embodiment, the average value SLP of the slip amount is calculated during the execution of the twin cut, and μ is determined according to the value of SLP to determine the actual road surface μ before starting the feedback control.
Correct the initial target opening degree θso according to the following. That is, if SLP is larger than the first predetermined value of 2 in step 144, it is determined that the road surface μ is small because the slip is large, and in step 146, the initial target opening degree θso is reset using the map for low μ. In step 148, the feedback control proportional constant β1. Set β2 to a value for low μ. If SJ, P is smaller than 2 in step 144, SLP is set to a second predetermined value of 3 in step 150.
Determine whether it is smaller. If it is smaller than K3, it is determined that μ is high, and the initial opening degree θ. (Step 152), β5
．． β2 (step 154) is set for high μ. In addition, if the SLP is between 2 and 3, the θ5 set in step 118 is left unchanged and β1, β2 for medium μ is set.
(Step 156) The preparation for feedback control is thus completed.

If FCIJT=0 in step 120, steps 132 to 156 are already execution methods, so step 1
Enter feedback control below 60. Step 160
In this case, the sub-throttle I valve opening limit '4B amount Δθ5 is Δθ5
-β1△ and →-β2△V.

8■ is the slip amount obtained in step 119, and 8 is the rate of change (differential value) thereof, and the slip amount ΔV(n) at the time of the current routine execution and the slip amount ΔV(n) at the previous execution.
3. (ΔV (n) - ΔV, □ - 0)) and β9 bow). Further, β1 and β2 are proportional constants determined according to the level of μ, and are determined in steps 144 to 156 immediately after the acceleration slip control is started, and thereafter in the routine shown in FIG. 5. β8. The value of β2 is set larger as the level of μ is higher.

In step 162, the target sub-throttle opening θ3° is determined as the sum of the current target sub-throttle opening and the control amount (-Δθ5), and is output to the step motor 18.

Steps 164 to 170 indicate conditions for ending acceleration slip control. In this embodiment, the acceleration slip control is terminated when the state in which the sub throttle valve opening θso becomes larger than the main throttle valve opening (step 164) continues for a predetermined time (step 1.70). At step 172, all flags are reset to zero and θ and 0 are fully opened. Further, at this time, α, β1β2 are all set to values for medium μ.

As explained above, according to this embodiment, since it is determined whether or not the road surface friction coefficient can be used for control by determining whether or not the vehicle is traveling on a slope, control is performed using a value of μ that is different from the actual road surface condition. Moreover, since the subthrottle valve is feedback-controlled from the initial setting opening degree according to the value of μ, responsiveness to changes in the road surface is improved.

Next, FIGS. 7 and 8 show another embodiment of the present invention. 7th
The figure shows a routine for calculating μ which corresponds to FIG. 4 of the above-described embodiment. In this example, the driven wheel speed VR (.) at the time of executing the routine this time and the driven wheel speed ■
+++n-++ and routine execution interval T. The vehicle body acceleration VR-(VR(.,-VR(,,-11)/To) is determined from the above, and the .mu. level is determined based on the magnitude of the threshold (steps 306 to 31/I).

This routine is also executed while the vehicle is traveling on a slope, and the slope determination is performed using the value 8 determined by this routine. (FIG. 8) FIG. 9 is a μ update determination routine corresponding to FIG. 5 of the above-described embodiment.

In FIG. 7, the μ level is determined regardless of whether or not the vehicle is running on a slope, so the flag FPO value is determined in step 351, and α, β1, β2, etc. are determined not to execute this routine while traveling on a slope. Preventing it from being updated.

〔Effect of the invention〕

The acceleration slip control device of the present invention calculates the road surface friction coefficient from the vehicle body acceleration and performs slip control according to the magnitude thereof, and prohibits the use of the calculated road surface friction coefficient for control when driving on a slope. This prevents execution of control using a value of μ that differs from the actual road surface condition, and ensures reliable control.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is an overall configuration diagram of an embodiment of an acceleration slip control device to which the present invention is applied, and FIGS. 3 to 6 show control operations of the same embodiment. Flowchart 1-1 FIGS. 7 to 9 are flowcharts showing control operations of other embodiments of the acceleration slip control device of the present invention, and FIG. 10 is a schematic diagram that does not show the operating principle of the acceleration sensor. . 10...Engine, 3a, :3b...Drive wheel, 4a, 4b...Driver wheel, 14...Main scooter 1
- control valve, 16... Sub throttle valve, 18... Step motor, 22a, 22b... Drive wheel rotation speed sensor, 24a,
24b... Driven wheel rotation speed sensor, 30... EFT
Unit, 34... Main throttle valve opening sensor, 36...
Zab throttle valve opening sensor, 50...TRC unit, 52...acceleration sensor.

Claims (1)

[Claims] 1. Slip detection means for detecting the amount of slip of the driving wheels, acceleration detection means for detecting the vehicle body running acceleration, and friction that calculates the road surface friction coefficient from the detected running acceleration and updates the road surface friction coefficient value used for control. An acceleration slip control device comprising a coefficient updating means and a control means for controlling drive torque according to the amount of slip of the driving wheels and the road surface friction coefficient, the slope detection means for detecting running on a slope; An acceleration slip control device comprising: a prohibiting means for prohibiting the friction coefficient updating means from updating a road surface friction coefficient when it is detected that the friction coefficient updating means has a road surface friction coefficient.