JP3575134B2 - Anti-skid control device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an anti-skid control device for a vehicle, and more particularly to an anti-skid control device provided with a front-rear G sensor for detecting a deceleration in a front-rear direction of a vehicle body.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a vehicle anti-skid control device, for example, when used in a four-wheel drive vehicle, since the four-wheel drive vehicle is restrained with respect to each other, the four-wheel drive vehicle tends to go to a locked state, and In performing skid control, it is difficult to accurately calculate the estimated vehicle speed. Therefore, an acceleration sensor (hereinafter, referred to as a G sensor) that detects the force generated in the front-rear direction of the vehicle body indirectly and converts the force into an electric signal to detect the deceleration in the front-rear direction of the vehicle body, A longitudinal acceleration sensor (hereinafter, referred to as a longitudinal G sensor) including a multi-step output type acceleration switch (hereinafter, referred to as a G switch) is used, and one information from the longitudinal G sensor is used as one information for calculating an estimated vehicle speed. Refer to information. The front-rear G sensor converts a force generated by acceleration or deceleration into a displacement of a vibrator, and converts the displacement into an electric signal using a resistor, a piezo element, a differential transformer, or the like. Type, optical type and electromagnetic type.
[0003]
[Problems to be solved by the invention]
The front-rear G sensor detects the deceleration of the vehicle body in the front-rear direction. When the vehicle travels on a sloping road, the amount of leaning of the vehicle body in the front-rear direction, that is, the inclination of the sloping road, is detected by the front-rear G sensor. Will be included in the output value from.
FIG. 1 shows an estimated vehicle body speed Vref, a maximum wheel speed Vmax, which is a maximum value among the wheel speeds of the respective wheels, and an output value of a front and rear G sensor (hereinafter, referred to as “below”) when the vehicle naturally decelerates without stepping on a brake pedal on a slope. FIG. 4 is a diagram showing a relationship between Gsns (referred to as front and rear G sensor values) and vehicle body wheel deceleration which is a deceleration actually received by the vehicle body.
[0004]
In FIG. 1, assuming that the slope angle of the slope is θ and the gravity acceleration is g (hereinafter, g indicates the gravity acceleration), the deceleration received by the vehicle running on the slope by the slope is (sin θ) × g. However, the front and rear G sensor values become zero. Further, the estimated vehicle speed Vref is calculated from the largest wheel speed Vmax among the wheel speeds of the respective wheels using the following equation (1), as in the following equation (1).
(Vref) _n = Vmax + ｛Vmax- (Vref) _n-1 ｝ / K ………………… (1)
In the above equation (1), k is a constant of k> 1, and (Vref) _n Is the Vref value in the current control cycle, and (Vref) _n-1 Is the Vref value in the previous control cycle.
[0005]
In the above equation (1), the front and rear G sensor value Gsns is defined as ΔVmax− (Vref), where the value in the direction in which the vehicle accelerates is positive and the value in the direction in which the vehicle decelerates is negative. _n-1 When｝ is smaller than a predetermined value {h (Gsns-m)} determined by the front and rear G sensor value Gsns, {Vmax- (Vref) _n-1 Is replaced by the predetermined value {h (Gsns-m)}, and the Vref value in the current control cycle is calculated. Note that h is a proportional constant of h> 0, m is m> 0, and the deceleration is a value larger by m than the value of the road surface μ during braking.
[0006]
Here, while the actual vehicle speed is the maximum wheel speed Vmax, the front and rear G sensor value Gsns is zero as described above, and the estimated vehicle speed Vref is calculated from the above equation (1) as the maximum wheel speed Vmax, that is, The vehicle speed is higher than the actual vehicle speed, and the vehicle is in a floating state. For example, at the time of deceleration, ΔVmax− (Vref) in the above equation (1) _n-1 と な り becomes a negative value, and the ｛Vmax− (Vref) _n-1 When｝ is replaced with the predetermined value {h (Gsns-m)}, Gsns becomes 0, so the estimated vehicle speed (Vref) in the current control cycle calculated by the above equation (1) is calculated. _n Is calculated to be larger than the actual vehicle speed, and is in a floating state.
[0007]
FIG. 2 shows the estimated vehicle speed Vref, the maximum wheel speed Vmax, the front-rear G sensor value Gsns, and the vehicle wheel deceleration when the vehicle is lightly stepped on the brake pedal while traveling on a slope in the state shown in FIG. It is a figure showing a relation.
In FIG. 2, for example, if a deceleration of 0.1 g is applied to the vehicle body by depressing the brake pedal to start the braking by setting the deceleration received by the vehicle body to 0.3 g on the slope, the deceleration actually applied to the vehicle body Is 0.4 g, the front and rear G sensor value Gsns is 0.1 g, and the ABS control is performed when the vehicle is on a road surface having a friction coefficient μ of about 0.1. In FIGS. 1 and 2, the deceleration is indicated by a positive value in the direction of acceleration and a negative value in the direction of deceleration.
[0008]
In general, ABS control is performed such that the lower the assumed road surface μ is, the longer the duration of the pressure reduction signal of the brake fluid pressure is, and the vehicle using the G sensor as the front and rear G sensor is used on a slope. When the brake pedal is depressed lightly during traveling, the deceleration detected by the G sensor is not corrected for the slope, and if such control is performed on a road having a higher μ, the stopping distance of the vehicle increases. In addition, there is a problem that the vehicle retreats on a slope. Further, even when the multi-stage output type G switch is used as the front and rear G sensor, the multi-stage output type switch outputs a discrete value, so that only the deceleration caused by the slope cannot be removed. As a result, similarly to the above, there is a problem that the stopping distance of the vehicle is extended and the vehicle retreats on the slope.
[0009]
The present invention has been made in order to solve the above-described problem, and has as its object to obtain a device that eliminates a delay in lowering the estimated vehicle body speed that directly causes the above-described problem.
[0010]
Means and effects for solving the problem
The present invention has a wheel speed sensor that detects a wheel speed of each wheel, and a front-rear G sensor that detects a deceleration in the front-rear direction of the vehicle body, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front-rear direction. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the deceleration detected by the G sensor and performs ABS control based on the estimated vehicle speed Vref. Selecting means for selecting a wheel speed Vmax and a minimum wheel speed Vmin as a minimum value; calculating a difference speed ΔS which is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin; Speed difference determining means for determining whether or not the vehicle speed is less than or equal to Vref determining means for determining whether or not the estimated vehicle body speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more; In a constant control cycle, the differential speed determining means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means determines that the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more. An anti-skid control device is provided, comprising: Vref reset means for performing a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax when the frequency becomes a predetermined value or more.
[0011]
As described above, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by the differential speed determining means and the Vref determining means without skidding all the wheels. The Vref reset means detects a state in which the state becomes larger than the value B, and performs a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax when the frequency of detecting the state becomes a predetermined value or more. Erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake pedal is lightly applied while driving is higher than the actual vehicle speed, can be prevented, the stopping distance of the vehicle increases, and Can be prevented from retreating on a slope, and the reliability of the ABS control can be improved.
[0012]
In the invention according to claim 2 of the present application, the Vref reset means according to claim 1 determines that the differential speed ΔS is equal to or less than a predetermined value A by the differential speed determining means, and When the Vref determining means determines that Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, the Vref determining means counts up. Otherwise, the counting means performs countdown, and the count value of the counting means becomes equal to or more than a predetermined value α. Then, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax.
[0013]
As described above, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by the differential speed determining means and the Vref determining means without skidding all the wheels. The Vref reset means detects a state in which the value has increased by more than the value B, and the Vref reset means measures the frequency of detecting the state by using the counting means. When this is detected, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. Therefore, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is determined by the actual vehicle speed. Erroneous ABS control that occurs when the vehicle is larger than the vehicle can be prevented, and the stopping distance of the vehicle can be increased, and the vehicle can be prevented from retreating on a slope. It can be, it is possible to improve the reliability of the ABS control.
[0014]
In the invention according to claim 3 of the present application, the differential speed determining means of claim 2 sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and sets the flag Fs. The second Vref determining means sets the flag Fv when it is determined that the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more, and the counting means counts up when all the flags Fs and Fv are set. The other is to count down.
[0015]
As described above, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by the differential speed determining means and the Vref determining means without skidding all the wheels. The Vref reset means detects a state in which the value has increased by more than the value B, and the Vref reset means measures the frequency of detecting the state by using the counting means. When this is detected, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. Therefore, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is determined by the actual vehicle speed. Erroneous ABS control that occurs when the vehicle is larger than the vehicle can be prevented, and the stopping distance of the vehicle can be increased, and the vehicle can be prevented from retreating on a slope. It can be, it is possible to improve the reliability of the ABS control.
[0016]
In the invention according to claim 4 of the present application, the Vref reset means according to claim 1 determines that the differential speed ΔS is equal to or less than a predetermined value A by the differential speed determining means, and When the Vref determining means determines that Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, the Vref determining means counts down. Otherwise, the counting means counts up. When the value becomes equal to or less than a predetermined value γ smaller than the value, a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed.
[0017]
As described above, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by the differential speed determining means and the Vref determining means without skidding all the wheels. The Vref reset means detects a state where the value has become larger than the value B, and the frequency of detecting the state is measured using the counting means, and the measured value is smaller than an initial value of the counting means. When it is detected that the frequency becomes equal to or more than the predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. It is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle speed Vref becomes higher than the actual vehicle speed, thereby increasing the stopping distance of the vehicle, and further increasing the vehicle speed. There it is possible to prevent the problem that retracts the slope, it is possible to improve the reliability of the ABS control.
[0018]
In the invention as set forth in claim 5 of the present application, the differential speed determining means of claim 4 sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and sets the flag Fs. The Vref determining means sets the flag Fv when the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by the predetermined value B or more, and the counting means according to claim 4 sets the flag Fs and the flag Fv all. And count up otherwise.
[0019]
As described above, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by the differential speed determining means and the Vref determining means without skidding all the wheels. The Vref reset means detects a state where the value has become larger than the value B, and the frequency of detecting the state is measured by the counting means, and the measured value becomes equal to or less than a predetermined value γ which is smaller than an initial value of the counting means. When the frequency is detected to be equal to or higher than a predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. It is possible to prevent the execution of erroneous ABS control that occurs when Vref becomes larger than the actual vehicle speed, thereby increasing the stopping distance of the vehicle and further increasing the vehicle stopping distance. There it is possible to prevent the problem that retracts the slope, it is possible to improve the reliability of the ABS control.
[0020]
The invention according to claim 6 of the present application has a wheel speed sensor that detects a wheel speed of each wheel, and a front-rear G sensor that detects a deceleration of the vehicle body in a front-rear direction. An anti-skid control device that calculates an estimated value Vref of the vehicle body speed from the wheel speeds of the respective wheels detected in the above and the deceleration detected by the front-rear G sensor and performs ABS control based on the estimated vehicle body speed Vref, Selecting means for selecting a maximum wheel speed Vmax which is the maximum value and a minimum wheel speed Vmin which is the minimum value among the wheel speeds of the respective wheels; and a differential speed ΔS which is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin. Differential speed determining means for determining whether or not the differential speed ΔS is equal to or less than a predetermined value A; and determining whether the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more. Vref determining means for determining whether the deceleration is equal to or greater than Vmax deceleration determining means for calculating the deceleration of the maximum wheel speed Vmax and determining whether the deceleration is equal to or greater than a predetermined value C. The differential speed determining means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means determines that the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more. Vref reset means for resetting the estimated vehicle body speed Vref to the maximum wheel speed Vmax when the frequency at which the Vmax deceleration determining means determines that the speed is equal to or higher than the predetermined value C becomes equal to or higher than the predetermined value. An anti-skid control device is provided.
[0021]
As described above, the Vmax deceleration determining means determines that the vehicle is on a sloping road when detecting the state where the deceleration of the maximum wheel speed Vmax is equal to or higher than the predetermined value C. The Vmax deceleration determining means determines that the vehicle is traveling on a hill, and the estimated vehicle speed Vref calculated by the differential speed determining means and the Vref determining means is calculated based on the actual vehicle speed without skidding all the wheels. The Vref reset means performs a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax when the frequency of detecting the state becomes equal to or more than the predetermined value. As a result, the erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope becomes larger than the actual vehicle speed is performed. It can be prevented facilities, stopping distance of the vehicle extends, and further the vehicle is able to prevent a problem that retracts the slope. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0022]
In the invention according to claim 7 of the present application, the Vref reset means of claim 6 determines that the differential speed ΔS is equal to or less than a predetermined value A by the differential speed determination means, and The Vref determining means determines that Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, and counts up when the Vmax deceleration determining means determines that the calculated deceleration is not less than a predetermined value C. Other than the above, there is provided a counting means for performing a countdown, and when the count value of the counting means becomes equal to or more than a predetermined value α, a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed.
[0023]
As described above, the Vmax deceleration determining means determines that the vehicle is on a sloping road when detecting the state where the deceleration of the maximum wheel speed Vmax is equal to or higher than the predetermined value C. The Vmax deceleration determining means determines that the vehicle is traveling on a hill, and the estimated vehicle speed Vref calculated by the differential speed determining means and the Vref determining means is calculated based on the actual vehicle speed without skidding all the wheels. The Vref reset means measures the frequency of detecting the state by the counting means, and the measured value becomes equal to or more than a predetermined value α, and the frequency becomes a predetermined value B. When it is detected that the vehicle speed has become equal to or higher than the predetermined value, the estimated vehicle speed Vref is reset to the maximum wheel speed Vmax. It is possible to prevent erroneous ABS control from being performed when the calculated estimated vehicle body speed Vref becomes higher than the actual vehicle body speed, to prevent a problem that the stopping distance of the vehicle is extended, and further, that the vehicle moves backward on a slope. Can be. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0024]
In the invention according to claim 8 of the present application, the differential speed determining means of claim 7 sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and sets the flag Fs. The Vref determining means sets a flag Fv when the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more, and the Vmax deceleration determining means determines that the calculated deceleration is a predetermined value. A flag Fg is set when it is determined to be not less than C, and the counting means counts up when all of the flags Fs, Fv and Fg are set, and counts down otherwise. .
[0025]
As described above, the Vmax deceleration determining means determines that the vehicle is on a sloping road when detecting the state where the deceleration of the maximum wheel speed Vmax is equal to or higher than the predetermined value C. The Vmax deceleration determining means determines that the vehicle is traveling on a hill, and the estimated vehicle speed Vref calculated by the differential speed determining means and the Vref determining means is calculated based on the actual vehicle speed without skidding all the wheels. The Vref reset means measures the frequency of detecting the state by the counting means, and the measured value becomes equal to or more than a predetermined value α, and the frequency becomes a predetermined value B. When it is detected that the vehicle speed has become equal to or higher than the predetermined value, the estimated vehicle speed Vref is reset to the maximum wheel speed Vmax. It is possible to prevent the erroneous ABS control from being performed when the calculated estimated vehicle speed Vref becomes higher than the actual vehicle speed, and to prevent a problem that the stopping distance of the vehicle is increased and the vehicle retreats on a slope. . Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0026]
In the invention according to claim 9 of the present application, the Vref reset means of claim 6 determines that the differential speed ΔS is equal to or less than a predetermined value A by the differential speed determining means, and The Vref determining means determines that Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, and counts down when the Vmax deceleration determining means determines that the calculated deceleration is not less than a predetermined value C. Has counting means for counting up, and when the count value of the counting means becomes equal to or less than a predetermined value γ smaller than the initial value of the counting means, reset operation for setting the estimated vehicle body speed Vref to the maximum wheel speed Vmax is performed. It is characterized by performing.
[0027]
As described above, the Vmax deceleration determining means determines that the vehicle is on a sloping road when detecting the state where the deceleration of the maximum wheel speed Vmax is equal to or higher than the predetermined value C. The Vmax deceleration determining means determines that the vehicle is traveling on a hill, and the estimated vehicle speed Vref calculated by the differential speed determining means and the Vref determining means is calculated based on the actual vehicle speed without skidding all the wheels. The Vref reset means measures the frequency of detecting the state by the counting means, and the measured value is smaller than the initial value of the counting means. When it is detected that the frequency becomes equal to or less than γ and the frequency becomes equal to or more than the predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. The erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake pedal is lightly applied during traveling is higher than the actual vehicle speed can be prevented, the stopping distance of the vehicle can be extended, and further, the vehicle can be stopped. The problem of retreating on a slope can be prevented. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0028]
In the invention set forth in claim 10 of the present application, the differential speed determining means of claim 9 sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and sets the flag Fs. In a ninth aspect, the Vref determining means sets a flag Fv when determining that the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, and the Vmax deceleration determining means according to the ninth aspect determines that the calculated deceleration is a predetermined value. A flag Fg is set when it is determined to be not less than C, and the counting means of the ninth aspect counts down when all of the flags Fs, Fv and Fg are set, and counts up otherwise. .
[0029]
As described above, the Vmax deceleration determining means determines that the vehicle is on a sloping road when detecting the state where the deceleration of the maximum wheel speed Vmax is equal to or higher than the predetermined value C. The Vmax deceleration determining means determines that the vehicle is traveling on a hill, and the estimated vehicle speed Vref calculated by the differential speed determining means and the Vref determining means is calculated based on the actual vehicle speed without skidding all the wheels. The Vref reset means measures the frequency of detecting the state by the counting means, and the measured value is smaller than the initial value of the counting means. When it is detected that the frequency becomes equal to or less than γ and the frequency becomes equal to or more than the predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. It is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake pedal is lightly applied during traveling is higher than the actual vehicle speed, the stopping distance of the vehicle is extended, and the vehicle is driven on a slope. The problem of retreat can be prevented. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0030]
In the invention as set forth in claim 11 of the present application, the Vref reset means according to claim 2, 3, 3, 7 or 8 sets the count value of the count means to be smaller than the predetermined value α. When the maximum wheel speed Vmax is zero, a reset operation is performed to set the estimated vehicle body speed Vref to zero when the maximum wheel speed Vmax is zero. As described above, the Vref reset means determines that the measured value measured by the counting means is equal to or greater than the predetermined value β which is smaller than the predetermined value α and the frequency is equal to or greater than the predetermined value which is smaller than the predetermined value α. When detecting and detecting that the vehicle has stopped, the estimated vehicle speed Vref is set to 0, so that it is possible to quickly detect that the vehicle has stopped, and when the brake is lightly applied while traveling on a slope. The erroneous ABS control that occurs when the calculated estimated vehicle speed Vref becomes higher than the actual vehicle speed can be prevented, and from these, the stopping distance of the vehicle traveling on a hill increases, and furthermore, the vehicle stops on the hill. Can be prevented more reliably.
[0031]
In the twelfth aspect of the present invention, the Vref reset means of the fourth, fifth, ninth and tenth aspects makes the count value of the count means greater than the predetermined value γ. When the maximum wheel speed Vmax is 0, a reset operation is performed to set the estimated vehicle speed Vref to 0 when the maximum wheel speed Vmax is equal to or smaller than a predetermined value δ smaller than the initial value of the counting means. As described above, the Vref reset means determines that the measured value measured by the counting means is equal to or less than the predetermined value δ which is larger than the predetermined value γ and is smaller than the initial value of the counting means, and When the vehicle is stopped and the state where the vehicle is stopped is detected, the estimated vehicle speed Vref is set to 0. Therefore, it is possible to detect that the vehicle has stopped quickly and to travel on a slope. It is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake pedal is lightly applied during the vehicle is higher than the actual vehicle speed. It is possible to more reliably prevent the problem that the distance is increased and the vehicle retreats on a slope.
[0032]
According to a thirteenth aspect of the present invention, there is provided a wheel speed sensor for detecting a wheel speed of each wheel, and a front and rear G sensor for detecting a deceleration of the vehicle body in a front and rear direction. An anti-skid control device that calculates an estimated value Vref of the vehicle body speed from the wheel speeds of the respective wheels detected in the above and the deceleration detected by the front-rear G sensor and performs ABS control based on the estimated vehicle body speed Vref, The maximum wheel speed Vmax, which is the maximum value, and the minimum wheel speed Vmin, which is the minimum value, are selected from the wheel speeds of the respective wheels, and the difference speed ΔS, which is the difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, is calculated. It is determined whether or not the differential speed ΔS is equal to or lower than a predetermined value A, and whether or not the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more is determined. When the frequency at which the difference speed ΔS is determined to be equal to or lower than the predetermined value A and the estimated vehicle speed Vref is determined to be higher than the maximum wheel speed Vmax by the predetermined value B or higher becomes equal to or higher than the predetermined value, the estimated vehicle speed Vref is decreased. An object of the present invention is to provide an anti-skid control device which performs a reset operation for setting the maximum wheel speed Vmax.
[0033]
In this way, when the vehicle is traveling on a slope, all the wheels are not skid, and a state where the calculated estimated vehicle speed Vref is higher than the actual vehicle speed by a predetermined value B or more is detected. When the frequency at which the state is detected becomes equal to or higher than a predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. Therefore, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is reduced. It is possible to prevent the erroneous execution of the ABS control that occurs when the vehicle speed becomes higher than the actual vehicle speed, to prevent the vehicle from being stopped at a longer distance, and to prevent the vehicle from retreating on a slope. Performance can be improved.
[0034]
The invention according to claim 14 of the present application has a wheel speed sensor for detecting a wheel speed of each wheel, and a front-rear G sensor for detecting a deceleration of the vehicle body in a front-rear direction. An anti-skid control device that calculates an estimated value Vref of the vehicle body speed from the wheel speeds of the respective wheels detected in the above and the deceleration detected by the front-rear G sensor and performs ABS control based on the estimated vehicle body speed Vref, The maximum wheel speed Vmax, which is the maximum value, and the minimum wheel speed Vmin, which is the minimum value, are selected from the wheel speeds of the respective wheels, and the difference speed ΔS, which is the difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, is calculated. A flag Fs is set when the difference speed ΔS is equal to or less than a predetermined value A, and a flag Fv is set when the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more. In a predetermined control cycle, when the frequency at which the flag Fs and the flag Fv are all set becomes equal to or higher than a predetermined value, a reset operation for setting the estimated vehicle body speed Vref to the maximum wheel speed Vmax is performed. A skid control device is provided.
[0035]
In this way, when the vehicle is traveling on a slope, all the wheels are not skid, and a state where the calculated estimated vehicle speed Vref is higher than the actual vehicle speed by a predetermined value B or more is detected. When the frequency at which the state is detected becomes equal to or higher than a predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. Therefore, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is reduced. It is possible to prevent the erroneous execution of the ABS control that occurs when the vehicle speed becomes higher than the actual vehicle speed, to prevent the vehicle from being stopped at a longer distance, and to prevent the vehicle from retreating on a slope. Performance can be improved.
[0036]
The invention according to claim 15 of the present application has a wheel speed sensor that detects a wheel speed of each wheel, and a front-rear G sensor that detects a deceleration of the vehicle body in the front-rear direction. An anti-skid control device that calculates an estimated value Vref of the vehicle body speed from the wheel speeds of the respective wheels detected in the above and the deceleration detected by the front-rear G sensor and performs ABS control based on the estimated vehicle body speed Vref, The maximum wheel speed Vmax, which is the maximum value, and the minimum wheel speed Vmin, which is the minimum value, are selected from the wheel speeds of the respective wheels, and the difference speed ΔS, which is the difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, is calculated. It is determined whether or not the differential speed ΔS is equal to or less than a predetermined value A, and it is determined whether or not the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more. The deceleration of the degree Vmax is calculated, and it is determined whether the deceleration is equal to or more than a predetermined value C. In a predetermined control cycle, it is determined that the differential speed ΔS is equal to or less than a predetermined value A, and the estimated vehicle speed is determined. When it is determined that Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more, and the frequency at which the deceleration of the maximum wheel speed Vmax is determined to be a predetermined value C or more becomes a predetermined value or more, the estimated vehicle body speed Vref is raised to the maximum value. An object of the present invention is to provide an anti-skid control device that performs a reset operation for setting the wheel speed to Vmax.
[0037]
As described above, when the state where the deceleration of the maximum wheel speed Vmax is equal to or more than the predetermined value C is detected, it is determined that the vehicle is traveling on a slope by determining that the vehicle is traveling on a slope by determining that the vehicle is traveling on a slope. If the calculated estimated vehicle speed Vref is higher than the actual vehicle speed by a predetermined value B or more without detecting skid of all the wheels, and the frequency at which the state is detected becomes higher than the predetermined value, Since the reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is higher than the actual vehicle speed. The execution of the ABS control can be prevented, and the stopping distance of the vehicle can be increased, and furthermore, it is possible to prevent the problem that the vehicle retreats on a slope. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0038]
The invention according to claim 16 of the present application has a wheel speed sensor that detects a wheel speed of each wheel, and a front and rear G sensor that detects a deceleration in the front and rear direction of the vehicle body, and the wheel speed sensor An anti-skid control device that calculates an estimated value Vref of the vehicle body speed from the wheel speeds of the respective wheels detected in the above and the deceleration detected by the front-rear G sensor and performs ABS control based on the estimated vehicle body speed Vref, The maximum wheel speed Vmax, which is the maximum value, and the minimum wheel speed Vmin, which is the minimum value, are selected from the wheel speeds of the respective wheels, and the difference speed ΔS, which is the difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, is calculated. A flag Fs is set when the difference speed ΔS is equal to or less than a predetermined value A, and a flag Fv is set when the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more. The deceleration of the maximum wheel speed Vmax is calculated, and if the deceleration is equal to or greater than a predetermined value C, a flag Fg is set. In a predetermined control cycle, the flags Fs, Fv, and Fg are all set. An object of the present invention is to provide an anti-skid control device characterized in that when the frequency becomes equal to or higher than a predetermined value, a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed.
[0039]
As described above, when the state where the deceleration of the maximum wheel speed Vmax is equal to or more than the predetermined value C is detected, it is determined that the vehicle is traveling on a slope by determining that the vehicle is traveling on a slope by determining that the vehicle is traveling on a slope. If the calculated estimated vehicle speed Vref is higher than the actual vehicle speed by a predetermined value B or more without detecting skid of all the wheels, and the frequency at which the state is detected becomes higher than the predetermined value, Since the reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax, the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is higher than the actual vehicle speed. The execution of the ABS control can be prevented, and the stopping distance of the vehicle can be increased, and furthermore, it is possible to prevent the problem that the vehicle retreats on a slope. Furthermore, it is possible to reduce the possibility that the reset operation is performed erroneously while the vehicle is traveling on a low μ road that is not a slope, and it is possible to reduce the occurrence of the problem that the wheels are easily locked and skid easily on the low μ road. From these facts, it is possible to improve the reliability of the ABS control.
[0040]
In the invention according to claim 17 of the present application, the frequency of claim 13 to claim 16 is equal to or higher than a predetermined value smaller than the predetermined value, and the maximum wheel speed Vmax is 0. Sometimes, a reset operation for setting the estimated vehicle speed Vref to 0 is performed. As described above, when it is detected that the frequency has become equal to or greater than the predetermined value of the smaller value and when the vehicle is stopped, the estimated vehicle speed Vref is set to 0. As a result, it is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle speed Vref calculated when the brake is lightly applied while traveling on a slope is higher than the actual vehicle speed. Thus, the stopping distance of the vehicle traveling on the slope can be extended, and the problem that the vehicle retreats on the slope can be more reliably prevented.
[0041]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in detail based on an embodiment shown in the drawings.
FIG. 3 is a schematic control system diagram showing the anti-skid control device according to the first embodiment of the present invention, and FIG. 4 is a schematic diagram showing the anti-skid control device according to the first embodiment of the present invention. FIG. 4 is a block diagram. First, an outline of a first embodiment of the anti-skid control device of the present invention will be described with reference to FIGS.
[0042]
The object to be controlled by the anti-skid control device according to the first embodiment of the present invention shown in FIGS. 3 and 4 is a four-wheeled vehicle, and includes a master cylinder 1 and wheel cylinders 2A corresponding to left and right front wheels and left and right rear wheels, respectively. , 2B, 2C, 2D, the inlet valves 3A, 3B, 3C, 3D comprising ON / OFF type electromagnetic valves are arranged, while the outlet cylinders 4A comprising the ON / OFF type electromagnetic valves from the wheel cylinders 2A to 2D. , 4B, 4C, 4D and a return line 7 for returning to the master cylinder 1 via a pump / motor 6. A buffer chamber 8 is disposed between the outlet valves 4A to 4D of the reflux line 7 and the pump motor 6. In addition, A, B, C, and D of the code | symbol which show a wheel cylinder, an inlet valve, and an outlet valve have shown the left-right front wheel and the right-left rear wheel of a vehicle, respectively.
[0043]
The wheel speed sensors S0 to S3 and the front and rear G sensor 5 are connected to a signal processing device 10 described later, and the wheel speed sensors S0, S1, S2, and S3 detect the respective speeds of the left and right front wheels and the left and right rear wheels. The detected speed is sent to the signal processing device 10 as a wheel speed signal. The front-rear G sensor 5 detects the deceleration of the vehicle body in the front-rear direction, and sends the detected deceleration to the signal processing device 10 as the front-rear G sensor value Gsns.
[0044]
The signal processing device 10 includes a microcomputer, and includes a basic control amount calculation unit 11, a differential speed determination unit 12, a Vref determination unit 13, a Vref reset unit 14, and a solenoid command output unit 15, as shown in FIG. A predetermined process is performed on the speed signal and the signal from the front / rear G sensor 5 to output a pressure-decompression signal Si to the actuators ACT0, ACT1, ACT2, and ACT3 having the inlet valves 3A to 3D and the outlet valves 4A to 4D. I do. The suffix i is i = 0, 1, 2, 3 and indicates the left and right front wheels and the left and right rear wheels of the vehicle together with the suffixes 0, 1, 2, and 3 indicating the wheel speed sensor and the actuator, respectively. In FIG. 3, any one of the four wheels of the four-wheeled vehicle is illustrated as an example, except for the master cylinder 1 and the signal processing device 10. The circle is shown.
[0045]
The wheel speed sensors S0 to S3 and the front and rear G sensor 5 are connected to the basic control amount calculation unit 11, and the basic control amount calculation unit 11 is connected to the differential speed determination unit 12, the Vref determination unit 13, and the solenoid command output unit 15. , The differential speed determination unit 12 and the Vref determination unit 13 are connected to the Vref reset unit 14. Further, the Vref reset unit 14 is connected to a solenoid command output unit 15, and the solenoid command output unit 15 is connected to actuators ACT0 to ACT3, respectively.
[0046]
The basic control amount calculation unit 11 calculates a wheel speed SPEEDi of each wheel representing the behavior of the wheel and the vehicle body based on the wheel speed signals input from the wheel speed sensors S0 to S3, and inputs the wheel speed SPEEDi from the front-rear G sensor 5. The vehicle body deceleration is calculated from the front and rear G sensor values Gsns, the estimated vehicle speed Vref is calculated from the wheel speed SPEEDi and the vehicle body deceleration, and the calculated values are output to the solenoid command output unit 15. Here, a method of calculating the wheel speed SPEEDi and the estimated vehicle body speed Vref is known, and as an example of a method of calculating the wheel speed SPEEDi, from the number p of pulse signals from the wheel speed sensor generated within a predetermined time Δt, It is calculated from the following equation (2).
SPEEDi = p / Δt × a (2)
In the above equation (2), a is a proportional constant. Further, the estimated vehicle speed Vref is calculated using the above equation (1) as an example of a method of calculating the estimated vehicle speed Vref.
[0047]
From the wheel speed SPEEDi and the estimated vehicle speed Vref input from the basic control amount calculation unit 11, the solenoid command output unit 15 determines, for example, Vref−SPEEDi ≧ (3 + Vref / 32) km / h and d / dt (SPEEDi). If ≦ −1.5 g, it is determined that a lock sign is detected, and a pressure increase / decrease signal Si for reducing the brake fluid pressure is output to each of the actuators ACT0 to ACT3, and no other lock sign is detected. Output the pressure increase / decrease signal Si for increasing or decreasing the brake fluid pressure.
[0048]
If the pressure increase / decrease signal Si from the solenoid command output unit 15 is “pressure reduction”, the outlet valves 4A to 4D of the actuators ACT0 to ACT3 are opened and the inlet valves 3A to 3D are closed, and the solenoid command output is performed. If the pressurized / depressurized signal Si from the unit 15 is “hold”, the outlet valves 4A to 4D and the inlet valves 3A to 3D are closed, and the pressurized / depressurized signal Si from the solenoid command output unit 15 is “pressurized”. ”, The inlet valves 3A to 3D are opened and the outlet valves 4A to 4D are closed.
[0049]
Further, the basic control amount calculation unit 11 selects the maximum wheel speed Vmax and the minimum wheel speed Vmin from the calculated wheel speeds SPEEDi for each wheel, and determines the maximum wheel speed Vmax and the minimum wheel speed Vmin by the differential speed. It outputs the estimated vehicle speed Vref and the maximum wheel speed Vmax to the Vref determination unit 13.
[0050]
The difference speed determination unit 12 calculates a difference speed ΔS that is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin input from the basic control amount calculation unit 11, and the difference speed ΔS is equal to or less than a predetermined value A. In this case, for example, when the speed is equal to or less than 2 km / h, a difference speed determination flag Fs indicating that the speed difference ΔS is equal to or less than a predetermined value A is set. As described above, in order to detect a situation in which all four wheels of a four-wheel vehicle are gripping on the road surface without skidding, the differential speed determination unit 12 requires that the wheel speeds of the four wheels be within a predetermined range. Is detected.
[0051]
When the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more than the maximum wheel speed Vmax and the estimated vehicle speed Vref input from the basic control amount calculation unit 11, the Vref determination unit 13 outputs, for example, 4 km / If it is greater than h, a Vref determination flag Fv indicating that the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more is set. As described above, the Vref determination unit 13 detects a floating state in which the estimated vehicle speed Vref indicates a value greater than the actual vehicle speed.
[0052]
When detecting that both the differential speed determination flag Fs and the Vref determination flag Fv are set, the Vref reset unit 14 determines that the estimated vehicle speed Vref has been calculated to be excessively large, and performs a built-in detection. If the counter CTR is incremented, and otherwise, that is, if it is detected that any one of the differential speed determination flag Fs and the Vref determination flag Fv has not been set, it is determined that the estimated vehicle speed Vref is not excessively calculated. Upon determination, the detection counter CTR is decremented. In this way, the Vref reset unit 14 measures the frequency of detecting the state in which the differential speed determination flag Fs and the Vref determination flag Fv are all set using the detection counter CTR.
[0053]
The Vref reset unit 14 determines that the counter value of the detection counter CTR is equal to or greater than a predetermined value α, for example, when the control cycle is 8 msec, the counter value is equal to or greater than 64 indicating 0.5 sec. When the frequency of detecting the state in which all of the Vref determination flags Fv are set becomes equal to or more than a predetermined value, it is determined that the vehicle is traveling on a sloping road, and a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed by the solenoid command. This is performed for the output unit 15. Further, even if the counter value of the detection counter CTR has not reached the predetermined value α, the counter value is not less than the predetermined value β which is smaller than the predetermined value α, for example, 32 or more when the control cycle is 8 msec, and Is stopped and the maximum wheel speed Vmax is 0, the estimated vehicle speed Vref is reset to 0.
[0054]
Note that the basic control amount calculation unit 11 serves as a selection unit, the difference speed determination unit 12 serves as a difference speed determination unit, the Vref determination unit 13 serves as a Vref determination unit, and the detection counter CTR serves as a count unit. The Vref reset section 14 forms Vref reset means.
[0055]
Next, FIG. 5 shows an operation example in which the anti-skid control device shown in FIG. 4 determines whether or not the vehicle is traveling on a slope and corrects the estimated vehicle speed Vref when traveling on a slope. FIG. 5 is a flowchart illustrating an operation example of correcting the estimated vehicle body speed Vref in the apparatus according to the first embodiment of the present invention with reference to FIG.
In FIG. 5, the basic control amount calculation unit 11 first calculates the wheel speed SPEEDi of each wheel in step S1, and calculates the maximum wheel speed Vmax and the minimum wheel speed Vmin from the calculated wheel speeds SPEEDi in step S2. Is calculated, and the estimated vehicle speed Vref is calculated in step S3, the maximum wheel speed Vmax and the minimum wheel speed Vmin are output to the differential speed determining unit 12, and the calculated estimated vehicle speed Vref and the maximum wheel speed Vmax are determined by the Vref determining unit. 13 is output.
[0056]
Next, in step S4, the differential speed determination unit 12 calculates the above differential speed ΔS from the maximum wheel speed Vmax and the minimum wheel speed Vmin input from the basic control amount calculation unit 11, and the calculated differential speed ΔS is 2 km / It is checked whether or not the speed difference is equal to or less than 2 km / h (YES). When the speed difference is equal to or less than 2 km / h (YES), the process proceeds to step S5. After setting the speed determination flag Fs, the process proceeds to step S6. If it is not less than 2 km / h in step S4 (NO), the process proceeds to step S6.
[0057]
In step S6, the Vref determination unit 13 determines whether the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by at least 4 km / h based on the maximum wheel speed Vmax and the estimated vehicle speed Vref input from the basic control amount calculation unit 11. If it is higher than 4 km / h (YES), the process proceeds to step S7, and in step S7, the Vref determination unit 13 determines that the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value or more. After setting, the process proceeds to step S8. If it is not larger than 4 km / h in step S6 (NO), the process proceeds to step S8.
[0058]
In step S8, the Vref reset unit 14 checks whether or not all of the differential speed determination flag Fs and the Vref determination flag Fv are set, and if it is detected that all are set (YES), the process proceeds to step S9. In step S9, the Vref reset unit 14 determines that the estimated vehicle speed Vref is excessively calculated, increments the detection counter CTR, and then proceeds to step S11. If it is determined in step S8 that any one of the differential speed determination flag Fs and the Vref determination flag Fv has not been set (NO), the process proceeds to step S10, and in step S10, the Vref reset unit 14 It is determined that the estimated vehicle speed Vref is not excessively calculated, the detection counter CTR is decremented, and the process proceeds to step S11.
[0059]
In step S11, the Vref reset unit 14 checks the counter value of the detection counter CTR, and when the counter value is equal to or larger than a predetermined value α, for example, when the control cycle is 8 msec, the counter value indicates 0.5 sec. When the maximum value of the CTR counter value is 255 and the minimum value is 0 (YES), the process proceeds to step S12, where the Vref reset unit 14 determines that the vehicle is traveling on a slope. Then, the solenoid command output unit 15 performs a reset operation to set the estimated vehicle speed Vref to the maximum wheel speed Vmax, clears the detection counter CTR to 0, and then proceeds to step S13. If the counter value is not 64 or more in step S11 (NO), the process proceeds to step S13.
[0060]
In step S13, the Vref reset unit 14 checks the counter value of the detection counter CTR, and when the counter value is equal to or more than a predetermined value β, for example, when the control cycle is set to 8 msec, the counter value is equal to or more than 32 and the maximum wheel speed If Vmax is 0 and the vehicle is stopped (YES), the process proceeds to step S14, and in step S14, the Vref reset unit 14 causes the solenoid command output unit 15 to reset the estimated vehicle speed Vref to 0 and performs detection. After the counter CTR is cleared to 0, the process returns to step S1. If the counter value is equal to or greater than 32 and the maximum wheel speed Vmax is not 0 in step S13 (NO), the process returns to step S1.
[0061]
As described above, in the device according to the first embodiment of the present invention, when the vehicle is traveling on a slope, as shown in FIG. 6, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed by a predetermined value. When the count value of the detection counter CTR that detects a state that is greater than the value B and measures the frequency of detecting the state becomes equal to or more than a predetermined value α, that is, when the frequency of detecting the state becomes equal to or more than a predetermined value, the estimated vehicle body is estimated. A reset operation for setting the speed Vref to the maximum wheel speed Vmax is performed. Even if the counter value of the detection counter CTR does not reach the predetermined value α, the counter value is equal to or larger than the predetermined value β smaller than the predetermined value α, and the vehicle stops and the maximum wheel speed Vmax becomes 0. , The estimated vehicle speed Vref is reset to zero. From these facts, it is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle body speed Vref calculated when lightly depressing the brake while traveling on a sloping road becomes higher than the actual vehicle body speed, and during hill running. It is possible to prevent a disadvantage that the stopping distance of the vehicle is increased and the vehicle retreats on a slope.
[0062]
In the anti-skid control device according to the first embodiment, when the detection counter CTR detects that both the differential speed determination flag Fs and the Vref determination flag Fv are set, the detection counter CTR increments and counts up. When detecting a state in which at least one of the flag Fs and the Vref determination flag Fv is not set, the counter decrements and counts down. However, when a state in which at least one of the differential speed determination flag Fs and the Vref determination flag Fv is not set is detected, the count may be incremented and incremented.
[0063]
In this case, when the count value of the detection counter CTR is equal to or less than the predetermined value γ, that is, when the frequency of detecting the state where all of the differential speed determination flag Fs and the Vref determination flag Fv are set becomes equal to or more than the predetermined value, It is determined that the vehicle is traveling on a slope, and a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed on the solenoid command output unit 15. Further, even if the counter value of the detection counter CTR is not equal to or smaller than the predetermined value γ, the counter value is equal to or smaller than the predetermined value δ which is larger than the predetermined value γ, and the vehicle stops and the maximum wheel speed Vmax is 0. If there is, the estimated vehicle speed Vref is reset to zero. The predetermined value δ is a value smaller than the initial value of the detection counter CTR.
[0064]
Next, in the anti-skid control device according to the first embodiment, when the vehicle is traveling on a low μ road, the Vref reset unit may cause the solenoid command output unit to erroneously perform the reset operation. In such a case, there is a problem that the wheels are locked and skid easily. Therefore, the anti-skid control device according to the first embodiment further calculates a deceleration from the maximum wheel speed Vmax, and erroneously performs the reset operation while the vehicle is traveling on a low μ road based on the calculated deceleration. A function of reducing the number of operations is added, and this is referred to as an anti-skid control device according to the second embodiment of the present invention.
[0065]
FIG. 7 is a schematic block diagram showing an anti-skid control device according to a second embodiment of the present invention, and an outline of the second embodiment of the anti-skid control device of the present invention will be described with reference to FIG. I do. A schematic control system diagram showing the anti-skid control device according to the second embodiment is the same as that of FIG. 3 except that the signal processing device 10 is replaced by the signal processing device 30, and thus a description thereof is omitted. In FIG. 7, the same components as those in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted here, and only the differences from FIG. 4 will be described.
[0066]
The difference between FIG. 7 and FIG. 4 is that the signal processor 10 of FIG. 4 calculates the deceleration by differentiating the maximum wheel speed Vmax and determines whether the calculated deceleration is equal to or greater than a predetermined value. 4 is added, the basic control amount calculation unit 11 in FIG. 4 outputs the maximum wheel speed Vmax to the Vmax deceleration determination unit 32, and the Vref reset unit 14 in FIG. The determination of the Vmax deceleration determination unit 31, the determination of whether or not to perform the reset operation on the solenoid command output unit 15 based on the differential speed determination flag Fs and the Vref determination flag Fv are performed. Accordingly, the basic control amount calculation unit 11 in FIG. 4 is referred to as a basic control amount calculation unit 31, the Vref reset unit 14 in FIG. 4 is referred to as a Vref reset unit 33, and the signal processing in FIG. In that the location 10 and the signal processor 30.
[0067]
7, the wheel speed sensors S0 to S3 and the front and rear G sensor 5 are connected to a signal processing device 30, which will be described later, and the wheel speed sensors S0 to S3 detect the respective speeds of the left and right front wheels and the left and right rear wheels. The detected speed is sent to the signal processing device 30 as a wheel speed signal. The front-rear G sensor 5 detects the deceleration of the vehicle body in the front-rear direction, and sends the detected deceleration to the signal processing device 30 as a front-rear G sensor value Gsns.
[0068]
The signal processing device 30 includes a microcomputer, and includes a basic control amount calculation unit 31, a differential speed determination unit 12, a Vmax deceleration determination unit 32, a Vref determination unit 13, a Vref reset unit 33, and a solenoid command output unit 15. A predetermined process is performed on the wheel speed signal and the signal from the front / rear G sensor 5 to output a pressure increase / decrease signal Si to the actuators ACT0, ACT1, ACT2, and ACT3.
[0069]
The basic control amount calculating unit 31 is connected to the differential speed determining unit 12, the Vref determining unit 13, the Vmax deceleration determining unit 32, and the solenoid command output unit 15, and the differential speed determining unit 12 and the Vref determining unit 13 are connected to the Vref reset unit 33. It is connected to the. Further, the Vref reset unit 33 is connected to the solenoid command output unit 15, and the solenoid command output unit 15 is connected to the actuators ACT0 to ACT3, respectively.
[0070]
The basic control amount calculation unit 31 calculates the wheel speed SPEEDi of each wheel representing the behavior of the wheels and the vehicle body based on the wheel speed signals input from the wheel speed sensors S0 to S3, and inputs the wheel speed SPEEDi from the front-rear G sensor 5. A vehicle deceleration is calculated from the front and rear G sensor values Gsns, and an estimated vehicle speed Vref is calculated from the wheel speed SPEEDi and the vehicle deceleration. Here, the method of calculating the wheel speed SPEEDi and the estimated vehicle speed Vref and the method of calculating the estimated vehicle speed Vref are the same as in the first embodiment, and will not be described here.
[0071]
Based on the wheel speed SPEEDi and the estimated vehicle speed Vref input from the basic control amount calculation unit 31, the solenoid command output unit 15 sends the pressurization signal to each of the actuators ACT0 to ACT3 in the same manner as in the first embodiment. Then, the actuators ACT0 to ACT3 perform the same operation as that of the first embodiment according to the pressurization / decompression signal Si.
[0072]
Further, the basic control amount calculation unit 31 selects the maximum wheel speed Vmax and the minimum wheel speed Vmin from the calculated wheel speeds SPEEDi for each wheel, and determines the maximum wheel speed Vmax and the minimum wheel speed Vmin by the differential speed. The maximum wheel speed Vmax is output to the determination unit 12, and the maximum wheel speed Vmax is output to the Vmax deceleration determination unit 32. Further, the basic control amount calculation unit 31 outputs the calculated estimated vehicle body speed Vref and the maximum wheel speed Vmax to the Vref determination unit 13. The operations of the differential speed determining unit 12 and the Vref determining unit 13 are the same as those of the first embodiment except that the speed data is input from the basic control amount calculating unit 31, and therefore the description thereof is omitted. . Further, the basic control amount calculating section 31 forms a selecting means.
[0073]
The Vmax deceleration determination unit 32 calculates the deceleration by differentiating the maximum wheel speed Vmax input from the basic control amount calculation unit 31, and when the calculated deceleration is equal to or greater than a predetermined value C, for example, d If /dt(Vmax)≦−0.75 g, a Vmax deceleration determination flag Fg indicating that the calculated deceleration is equal to or greater than the predetermined value C is set. As described above, the Vmax deceleration determining unit 32 reduces the possibility that the Vref reset unit 33 erroneously performs the reset operation on the solenoid command output unit 15 while the vehicle is traveling on a low μ road. In the deceleration, the value in the direction of acceleration is positive, and the value in the direction of deceleration is negative. Further, the Vmax deceleration determining section 32 forms Vmax deceleration determining means.
[0074]
If the Vref reset unit 33 detects that the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv are all set, the estimated vehicle speed Vref is excessively calculated. And the detection counter CTR is incremented. In other cases, that is, when it is detected that any one of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv has not been set. It is determined that the estimated vehicle speed Vref is not excessively calculated, and the detection counter CTR is decremented. In this way, the Vref reset unit 33 measures, using the detection counter CTR, the frequency of detecting the state in which the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv are all set. I do.
[0075]
Further, the Vref reset unit 33 determines that the counter value of the detection counter CTR is equal to or greater than a predetermined value α, for example, when the control cycle is 8 msec, the counter value is equal to or greater than 64 indicating 0.5 sec. When the frequency of detecting the state in which the Vmax deceleration determination flag Fg and the Vref determination flag Fv are all set is equal to or greater than a predetermined value, it is determined that the vehicle is traveling on a slope and the estimated vehicle speed Vref is set to the maximum wheel speed Vmax. The reset operation is performed on the solenoid command output unit 15. Further, even if the counter value of the detection counter CTR has not reached the predetermined value α, the Vref reset unit 33 determines that the counter value is equal to or larger than a predetermined value β smaller than the predetermined value α, for example, when the control cycle is 8 msec. If the above is the case and the vehicle stops and the maximum wheel speed Vmax is 0, the estimated vehicle speed Vref is reset to 0. Note that the Vref reset section 33 forms Vref reset means.
[0076]
Next, FIG. 8 illustrates an operation example in which the anti-skid control device shown in FIG. 7 determines whether the vehicle is traveling on a slope and corrects the estimated vehicle body speed Vref when traveling on a slope. FIG. 8 is a flowchart illustrating an operation example of correcting the estimated vehicle body speed Vref in the device according to the second embodiment of the present invention with reference to FIG. In FIG. 8, the same reference numerals as those in FIG. 5 denote the same steps as those in FIG. 5, except that the basic control amount calculation unit 11 is a basic control amount calculation unit 31 and the Vref reset unit 14 is a Vref reset unit 33. Here, description thereof will be omitted, and only different points from FIG. 5 will be described.
[0077]
8 differs from FIG. 5 in that steps S21 and S22 are added between steps S4 and S5 and step S6 in FIG. 5, and step S3 in FIG. That is, step S8 in FIG. 5 is replaced with step S23.
In FIG. 8, after performing the process of step S2, the basic control amount calculating unit 31 proceeds to step S20, calculates the estimated vehicle speed Vref in step S20, and determines the maximum wheel speed Vmax and the minimum wheel speed Vmin as a difference speed determination. The maximum wheel speed Vmax is output to the Vmax deceleration determination unit 32, and the calculated estimated vehicle speed Vref and the maximum wheel speed Vmax are output to the Vref determination unit 14. Then, the process proceeds to step S4. .
[0078]
If the differential speed ΔS is not equal to or less than 2 km / h in step S4 (NO), the process proceeds to step S21, and after the process of step S5 is performed, the process proceeds to step S21. In step S21, the Vmax deceleration determining unit 32 calculates the deceleration d / dt (Vmax) by differentiating the maximum wheel speed Vmax input from the basic control amount calculation unit 31, and calculates the calculated deceleration d / dt. It is determined whether or not (Vmax) is equal to or less than -0.75 g. If it is equal to or less than -0.75 g (YES), the process proceeds to step S22, and in step S22, the Vmax deceleration determining unit 32 determines whether the deceleration d / After setting a Vmax deceleration determination flag Fg indicating that dt (Vmax) is equal to or greater than a predetermined value, the process proceeds to step S6. If it is not less than -0.75 g in step S21 (NO), the process proceeds to step S6.
[0079]
In step S6, when the estimated vehicle speed Vref is not higher than the maximum wheel speed Vmax by 4 km / h or more (NO), the process proceeds to step S23, and after the process of step S7 is performed, the process proceeds to step S23. In step S23, the Vref reset unit 33 checks whether or not all of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv are set, and detects that all are set. In this case (YES), the process proceeds to step S9, and if it is detected that any one of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv has not been set (NO), the process proceeds to step S10. , And performs the processing after step S10.
[0080]
As described above, in the device according to the second embodiment of the present invention, when the vehicle is traveling on a slope, the calculated estimated vehicle speed Vref is smaller than the actual vehicle speed as shown in FIG. Is greater than or equal to a predetermined value B, and the deceleration of the maximum wheel speed Vmax is equal to or greater than a predetermined value C, and the count value of a detection counter CTR for measuring the frequency of detecting the state is equal to or greater than a predetermined value α. , That is, when the frequency of detecting the above state becomes equal to or more than a predetermined value, a reset operation is performed to set the estimated vehicle speed Vref to the maximum wheel speed Vmax. Even if the counter value of the detection counter CTR does not reach the predetermined value α, the counter value is equal to or larger than the predetermined value β smaller than the predetermined value α, and the vehicle stops and the maximum wheel speed Vmax becomes 0. , The estimated vehicle speed Vref is reset to zero.
[0081]
From these facts, it is possible to prevent the execution of erroneous ABS control that occurs when the estimated vehicle body speed Vref calculated when lightly depressing the brake while traveling on a sloping road becomes higher than the actual vehicle body speed, and during hill running. It is possible to prevent a disadvantage that the stopping distance of the vehicle is increased and the vehicle retreats on a slope. In addition, it is possible to reduce the possibility that the reset operation is performed by mistake while the vehicle is traveling on the low μ road, and it is possible to reduce the occurrence of a problem that the wheels are easily locked and skid easily on the low μ road.
[0082]
In the anti-skid control device according to the second embodiment, when the detection counter CTR detects a state where all of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv are set, the detection counter CTR increments and counts up. When detecting that at least one of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv is not set, the count value is decremented and the countdown is performed, but the differential speed determination flag Fs, the Vmax deceleration determination flag When detecting the state in which all of the Fg and Vref determination flags Fv are set, the count is decremented and the countdown is performed. Then the incremental It may be counted up to the door.
[0083]
In this case, the Vref reset unit 33 detects the frequency at which the counter value of the detection counter CTR is equal to or less than the predetermined value γ, that is, the state in which all of the differential speed determination flag Fs, the Vmax deceleration determination flag Fg, and the Vref determination flag Fv are set. Is greater than or equal to a predetermined value, it is determined that the vehicle is traveling on a slope, and the solenoid command output unit 15 performs a reset operation to set the estimated vehicle body speed Vref to the maximum wheel speed Vmax. Further, even if the counter value of the detection counter CTR is not equal to or smaller than the predetermined value γ, the counter value is equal to or smaller than the predetermined value δ which is larger than the predetermined value γ, and the vehicle stops and the maximum wheel speed Vmax is 0. If there is, the estimated vehicle speed Vref is reset to zero. The predetermined value δ is a value smaller than the initial value of the detection counter CTR.
[0084]
In the anti-skid control devices according to the first and second embodiments, the detection counter CTR is incremented or decremented by one, but the number of count-ups or count-downs at one time is determined by the differential speed ΔS It may be made to vary with other variables such as the value of the estimated vehicle speed Vref and the like.
[Brief description of the drawings]
FIG. 1 is a diagram showing the effect of a conventional anti-skid control device when a vehicle naturally decelerates on a slope without depressing a brake pedal.
FIG. 2 is a diagram showing the effect of a conventional anti-skid control device when a vehicle brakes lightly while traveling on a slope.
FIG. 3 is a schematic control system diagram showing the anti-skid control device according to the first embodiment of the present invention.
FIG. 4 is a schematic block diagram showing an anti-skid control device according to the first embodiment of the present invention.
FIG. 5 is a flowchart showing an operation example of calculating and correcting an estimated vehicle speed Vref in the device shown in FIG. 4;
FIG. 6 is a diagram showing Vref when the vehicle is running on a slope when the anti-skid control device according to the first embodiment of the present invention is used.
FIG. 7 is a schematic block diagram showing an anti-skid control device according to a second embodiment of the present invention.
FIG. 8 is a flowchart showing an operation example of calculating and correcting an estimated vehicle speed Vref in the device shown in FIG. 7;
[Explanation of symbols]
5 Front and rear G sensor
10,30 signal processing device
11, 31 Basic control amount calculation unit
12 Speed difference judgment section
13 Vref determination unit
14,33 Vref reset unit
15 Solenoid command output section
32 Vmax deceleration judgment unit
S0, S1, S2, S3 Wheel speed sensor
ACT0, ACT1, ACT2, ACT3 Actuator
CTR detection counter

Claims (17)

It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
Selecting means for selecting a maximum wheel speed Vmax which is a maximum value and a minimum wheel speed Vmin which is a minimum value among the wheel speeds of the respective wheels;
A differential speed determining unit that calculates a differential speed ΔS that is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and determines whether the differential speed ΔS is equal to or less than a predetermined value A;
Vref determining means for determining whether the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more;
In a predetermined control cycle, the differential speed determining means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means determines that the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more. An anti-skid control device, comprising: Vref reset means for performing a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax when the frequency becomes a predetermined value or more. The anti-skid control device according to claim 1, wherein the Vref reset means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the estimated vehicle speed Vref is greater than a maximum wheel speed Vmax. When the Vref determining means determines that the value is greater than the predetermined value B, the counting means counts up. Otherwise, the counting means counts down. When the count value of the counting means exceeds a predetermined value α, the estimated vehicle speed Vref An anti-skid control device, which performs a reset operation to set the maximum wheel speed Vmax. 3. The anti-skid control device according to claim 2, wherein said differential speed determining means sets a flag Fs when determining that said differential speed ΔS is equal to or less than a predetermined value A, and said Vref determining means sets an estimated vehicle speed Vref. Is determined to be greater than the maximum wheel speed Vmax by a predetermined value B or more, a flag Fv is set, and the counting means counts up when all the flags Fs and Fv are set, and counts down otherwise. Anti-skid control device. The anti-skid control device according to claim 1, wherein the Vref reset means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the estimated vehicle speed Vref is greater than a maximum wheel speed Vmax. When the Vref determining means determines that the value is greater than the predetermined value B, the countdown is performed when the Vref determining means determines that the value is larger than the predetermined value B. Otherwise, the counting means counts up, and the predetermined value γ is smaller than the initial value of the counting means. An anti-skid control device which performs a reset operation to set the estimated vehicle speed Vref to the maximum wheel speed Vmax when the following is reached. 5. The anti-skid control device according to claim 4, wherein said differential speed determining means sets a flag Fs when determining that said differential speed ΔS is equal to or less than a predetermined value A, and said Vref determining means sets an estimated vehicle speed Vref. Is determined to be greater than the maximum wheel speed Vmax by a predetermined value B or more, a flag Fv is set, and the counting means counts down when all the flags Fs and Fv are set, and counts up otherwise. Anti-skid control device. It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
Selecting means for selecting a maximum wheel speed Vmax which is a maximum value and a minimum wheel speed Vmin which is a minimum value among the wheel speeds of the respective wheels;
A differential speed determining unit that calculates a differential speed ΔS that is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and determines whether the differential speed ΔS is equal to or less than a predetermined value A;
Vref determining means for determining whether the estimated vehicle speed Vref is greater than the maximum wheel speed Vmax by a predetermined value B or more;
Vmax deceleration determining means for calculating a deceleration of the maximum wheel speed Vmax and determining whether the deceleration is equal to or greater than a predetermined value C;
In a predetermined control cycle, the differential speed determining means determines that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means determines that the estimated vehicle speed Vref is greater than a maximum wheel speed Vmax by a predetermined value B or more. When the frequency at which the Vmax deceleration determining means determines that the calculated deceleration is equal to or higher than the predetermined value C is equal to or higher than the predetermined value, a Vref reset is performed to reset the estimated vehicle speed Vref to the maximum wheel speed Vmax. And an anti-skid control device. 7. The anti-skid control device according to claim 6, wherein the Vref reset unit determines that the differential speed ΔS is equal to or less than a predetermined value A, and the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax. A counting means for counting up when the Vref determining means determines that the calculated deceleration is greater than or equal to a predetermined value C, and counting down otherwise; An anti-skid control device, wherein when the count value of the counting means becomes equal to or more than a predetermined value α, a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed. 8. The anti-skid control device according to claim 7, wherein the differential speed determining means sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means sets the estimated vehicle speed Vref. Is determined to be greater than the maximum wheel speed Vmax by a predetermined value B or more, the flag Fv is set. When it is determined that the calculated deceleration is equal to or more than the predetermined value C, the flag Fg is set. The anti-skid control device is characterized in that the means counts up when all of the flags Fs, Fv, and Fg are set, and counts down otherwise. 7. The anti-skid control device according to claim 6, wherein the Vref reset unit determines that the differential speed ΔS is equal to or less than a predetermined value A, and the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax. Counting means that counts down when the Vref determining means determines that the value is greater than or equal to a predetermined value B, and that the Vmax deceleration determining means determines that the calculated deceleration is equal to or greater than a predetermined value C, and counts up otherwise. And resetting the estimated vehicle speed Vref to the maximum wheel speed Vmax when the count value of the counting means becomes equal to or less than a predetermined value γ smaller than the initial value of the counting means. Skid control device. 10. The anti-skid control device according to claim 9, wherein the differential speed determining means sets a flag Fs when determining that the differential speed ΔS is equal to or less than a predetermined value A, and the Vref determining means sets the estimated vehicle speed Vref. Is determined to be greater than the maximum wheel speed Vmax by a predetermined value B or more, the flag Fv is set. When it is determined that the calculated deceleration is equal to or more than the predetermined value C, the flag Fg is set. The anti-skid control device is characterized in that the means counts down when all of the flags Fs, Fv and Fg are set, and counts up otherwise. In the anti-skid control device according to any one of claims 2, 3, 7, and 8, the Vref reset means sets the count value of the count means to a value smaller than the predetermined value α. When the maximum wheel speed Vmax is 0, a reset operation for setting the estimated vehicle speed Vref to 0 is performed when the maximum wheel speed Vmax is 0 or more. In the anti-skid control device according to any one of claims 4, 5, 9, and 10, the Vref reset means includes: a count value of the counting means being larger than the predetermined value γ; An anti-skid control device, wherein when the maximum wheel speed Vmax is 0, a reset operation is performed to set the estimated vehicle speed Vref to 0 when the count value becomes equal to or less than a predetermined value δ smaller than an initial value of the counting means. It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
The maximum wheel speed Vmax which is the maximum value and the minimum wheel speed Vmin which is the minimum value are selected from the wheel speeds of the respective wheels,
Calculating a difference speed ΔS between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and determining whether the difference speed ΔS is equal to or less than a predetermined value A;
It is determined whether the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more,
In a predetermined control cycle, when the frequency at which the difference speed ΔS is determined to be equal to or lower than the predetermined value A and the frequency at which the estimated vehicle speed Vref is determined to be higher than the maximum wheel speed Vmax by the predetermined value B or more becomes equal to or higher than the predetermined value, the estimated vehicle speed is increased. An anti-skid control device for performing a reset operation for setting the speed Vref to the maximum wheel speed Vmax. It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
The maximum wheel speed Vmax which is the maximum value and the minimum wheel speed Vmin which is the minimum value are selected from the wheel speeds of the respective wheels,
Calculating a difference speed ΔS that is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and setting a flag Fs when the difference speed ΔS is equal to or less than a predetermined value A;
When the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more, a flag Fv is set,
In a predetermined control cycle, when the frequency at which the flag Fs and the flag Fv are all set becomes equal to or higher than a predetermined value, a reset operation for setting the estimated vehicle speed Vref to the maximum wheel speed Vmax is performed. Control device. It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
The maximum wheel speed Vmax which is the maximum value and the minimum wheel speed Vmin which is the minimum value are selected from the wheel speeds of the respective wheels,
Calculating a difference speed ΔS between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and determining whether the difference speed ΔS is equal to or less than a predetermined value A;
It is determined whether the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more,
The deceleration of the maximum wheel speed Vmax is calculated, and it is determined whether the deceleration is equal to or more than a predetermined value C,
In a predetermined control cycle, it is determined that the differential speed ΔS is equal to or lower than a predetermined value A, and that the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more, and that the deceleration of the maximum wheel speed Vmax is equal to or lower than a predetermined value. An anti-skid control device that performs a reset operation to set the estimated vehicle speed Vref to the maximum wheel speed Vmax when the frequency at which the frequency is determined to be equal to or higher than the value C is equal to or higher than a predetermined value. It has a wheel speed sensor for detecting the wheel speed of each wheel, and a front and rear G sensor for detecting the deceleration of the vehicle body in the front and rear direction, and detects the wheel speed of each wheel detected by the wheel speed sensor and the front and rear G sensor. An anti-skid control device that calculates an estimated value Vref of the vehicle speed from the obtained deceleration and performs ABS control based on the estimated vehicle speed Vref,
The maximum wheel speed Vmax which is the maximum value and the minimum wheel speed Vmin which is the minimum value are selected from the wheel speeds of the respective wheels,
Calculating a difference speed ΔS that is a difference between the maximum wheel speed Vmax and the minimum wheel speed Vmin, and setting a flag Fs when the difference speed ΔS is equal to or less than a predetermined value A;
When the estimated vehicle speed Vref is higher than the maximum wheel speed Vmax by a predetermined value B or more, a flag Fv is set,
The deceleration of the maximum wheel speed Vmax is calculated, and if the deceleration is equal to or more than the predetermined value C, a flag Fg is set,
In a predetermined control cycle, when the frequency at which the flag Fs, the flag Fv, and the flag Fg are all set becomes equal to or higher than a predetermined value, a reset operation for setting the estimated vehicle body speed Vref to the maximum wheel speed Vmax is performed. Anti-skid control device. The anti-skid control device according to any one of claims 13 to 16, wherein the frequency is equal to or higher than a predetermined value smaller than the predetermined value and the maximum wheel speed Vmax is 0. An anti-skid control device for performing a reset operation for setting the speed Vref to 0.

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