JP4158680B2 - Vehicle behavior control device - Google Patents

Description

  The present invention relates to a vehicle behavior control device that controls the behavior of a vehicle.

Conventionally, as a control device for controlling the behavior of a vehicle, as described in Japanese Patent Laid-Open No. 11-64376, a control device for controlling the motion of a vehicle based on detection values of a yaw rate sensor and a lateral acceleration sensor. It is known that the abnormality of the yaw rate sensor is determined based on the detection value of the lateral acceleration sensor. This device determines that the yaw rate sensor is abnormal when the detection value of the lateral acceleration sensor changes more than a predetermined value when the detection value of the yaw rate sensor is stable, and tries to detect the abnormality of the yaw rate sensor. It is.
Japanese Patent Laid-Open No. 11-64376

  In general, yaw rate sensors and lateral acceleration sensors have variations in sensor detection accuracy, and it is difficult to accurately detect sensor abnormalities. For this reason, it is preferable to perform control in consideration of an abnormal state of the sensor.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle behavior control device that prevents inappropriate vehicle behavior control when a sensor is abnormally operated.

That is, the vehicle behavior control device according to the present invention is a vehicle behavior control device that performs vehicle behavior control using at least a lateral acceleration sensor and a yaw rate sensor, and the output fluctuation range of the lateral acceleration sensor is the same in the same behavior state of the vehicle. When the output fluctuation width of the yaw rate sensor is smaller than the first fluctuation value and the output fluctuation width of the yaw rate sensor is larger than the second fluctuation value, the behavior control is less likely to be started compared to the case where the output fluctuation width of the yaw rate sensor is equal to or smaller than the second fluctuation value. The behavior control start condition is changed . The behavior control start condition is to calculate the target yaw rate of the vehicle using the output of the lateral acceleration sensor, and the deviation between the target yaw rate and the output of the yaw rate sensor starts the control. The control start threshold value is constant when the output fluctuation range of the yaw rate sensor is equal to or less than the second fluctuation value. There is set, in which the output fluctuation width of the yaw rate sensor is set to a hard value is started behavior control greater the output fluctuation width of the yaw rate sensor is greater than a second change value.

According to these inventions, when the output of the lateral acceleration sensor is determined to be small and abnormal, the behavior control start condition is changed so that it is difficult to control. Thereby, it can prevent that control is started accidentally. Therefore, it is possible to prevent inappropriate behavior control from being performed when a sensor abnormality occurs.

  According to the present invention, it is possible to prevent inappropriate vehicle behavior control when there is a malfunction in a sensor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic configuration diagram of a vehicle behavior control device according to an embodiment of the present invention, and FIG. 2 is a hydraulic circuit diagram of a brake system in the vehicle behavior control device.

As shown in FIG. 1 and FIG. 2, the vehicle behavior control apparatus according to the present embodiment includes the wheels 15 _FL , 15 _FR , 15 _RR , 15 _RL (subscripts FL, FR, RR, RL are the left front wheel, the right wheel, respectively) The components corresponding to the front wheel, the left rear wheel, and the right rear wheel are represented. Hereinafter, the components corresponding to all four wheels are represented at a time such as wheels 15 _FL to 15 _RR . A brake ECU 1 that controls the hydraulic pressure supplied to the provided wheel cylinders 31 _{FL to} 31 _RR is provided. Further, the vehicle behavior control device includes a hydro booster 2 that generates hydraulic pressure to be supplied to each of the wheel cylinders 31 _{FL to} 31 _RR , and a brake actuator 3 that controls the hydraulic pressure based on an instruction from the brake ECU 1.

The brake ECU 1 includes output signals from the hydraulic pressure sensors 32, 33, wheel cylinder pressure sensors 34 _{FL to} 34 _RR , and accumulator pressure sensors 27, 28 for detecting the hydraulic pressure at various points in the brake system, which will be described later. And each sensor for detecting the vehicle state amount and the steering amount, for example, the wheel speed sensors 16 _{FL to} 16 _RR for detecting the wheel speed provided on each wheel, the yaw rate sensor 42 for detecting the yaw rate of the vehicle, Output signals of a lateral acceleration sensor 44 that detects lateral acceleration and a steering angle sensor 46 that detects a steering angle steered by the driver are input. Further, the brake ECU 1 has a function of controlling the operation of the solenoid valves 35 _{FL to} 35 _RR , 36 _{FL to} 36 _RR , 37 to 40 and the pump 24 in the actuator 3.

  As the lateral acceleration sensor 44, for example, a sensor having a movable part that moves or deforms when a lateral acceleration is applied to the vehicle and detects the lateral acceleration of the vehicle based on the movement of the movable part or the like is used. It is done. In this case, if the movable part is fixed and no longer moves, a detection signal corresponding to the lateral acceleration cannot be output, resulting in an abnormal operation.

  The hydro booster 2 is connected to the brake pedal 11 and generates a hydraulic pressure corresponding to the brake depression force. The hydro booster 2 is configured around a master cylinder 21 having a booster function for increasing the hydraulic pressure, and stores brake fluid as hydraulic oil. The reservoir 22, the electric pump 24 that increases the hydraulic pressure of the brake fluid supplied from the reservoir 22, the accumulator 23 that stores the high pressure generated by the pump 24, and the pressure generated by the pump 24 reaches a predetermined high pressure or higher. And a relief valve 25 for returning the brake fluid to the reservoir 22. Accumulator pressure sensors 27 and 28 are disposed between the accumulator 23 and the brake actuator 3. Accumulator pressure sensors 27 and 28 have different measurement ranges.

Brake actuator 3 is for controlling the hydraulic pressure supplied to each wheel cylinder 31 _FL to 31 _RR, and decompression linear solenoid valve 35 _FL to 35 _RR for holding corresponding to the respective wheel cylinders 31 _FL to 31 _RR Linear solenoid valves 36 _{FL to} 36 _RR for wheel cylinders and wheel cylinder pressure sensors 34 _{FL to} 34 _RR for detecting wheel cylinder pressure are provided. Further, switching solenoid valves 37 to 40 for supplying hydraulic pressure supplied from the master cylinder 21 at the time of system failure, and master pressure sensors 32 and 33 for detecting the master cylinder pressure are provided.

The holding linear solenoid valve 35 _{FL to} 35 _RR and the pressure reducing linear solenoid valve 36 _{FL to} 36 _RR are all connected in series to each other, and the wheel cylinder 31 to which the pipe branched from the middle corresponds. Connected to _{FL to} 31 _RR . Wheel cylinder pressure sensors 34 _{FL to} 34 _RR are arranged on these pipes, respectively. Both ends of the holding linear solenoid valves 35 _{FL to} 35 _RR and the pressure reducing linear solenoid valves 36 _{FL to} 36 _RR are connected in parallel between the accumulator 23 and the reservoir 22, respectively.

Master pressure sensors 32 and 33 are respectively disposed on the two pipes extending from the master cylinder 21 and connected to the pipes extending to the wheel cylinders 31 _FR and 31 _RR through switching solenoid valves 37 and 38, respectively. Further, the front wheel wheel cylinders 31 _FR and 31 _FL are connected to each other via a switching solenoid valve 39, and the rear wheel wheel cylinders 31 _RR and 31 _RL are connected to each other via a switching solenoid valve 40.

Here, the linear solenoid valves 35 _{FL to} 35 _RR and 36 _{FL to} 36 _RR are all closed when OFF, and control the flow rate in proportion to the control current when ON, and the switching solenoid valves 37 to 40 are all. It opens when it is OFF, and closes when it is ON.

Therefore, at the time of system failure, the linear solenoid valves 35 _{FL to} 35 _RR and 36 _{FL to} 36 _RR are all closed, but the switching solenoid valves 37 to 40 are all open, so that they are generated by the master cylinder 2. The hydraulic pressure is supplied directly to each of the wheel cylinders 31 _{FL to} 31 _RR so that a necessary braking force can be secured.

Under normal conditions, the brake ECU 1 refers to the detected values of the wheel cylinder pressure sensors 34 _{FL to} 34 _RR so that the hydraulic pressure applied to the wheel cylinders 31 _{FL to} 31 _RR becomes the set control oil pressure Pc, respectively. The valves 35 _{FL to} 35 _RR and 36 _{FL to} 36 _RR and the operation of the pump motor 24 are controlled.

Specifically, the case of the right front wheel 15 _FR will be described as an example. When the current wheel cylinder pressure Pm is lower than the control oil pressure Pc, that is, when pressure increase is necessary (hereinafter referred to as pressure increase mode), By closing the linear solenoid valve 36 _FL and opening the holding linear solenoid valve 35 _FR , the high pressure brake fluid on the accumulator 23 side is supplied to the wheel cylinder 31 _FR to increase its pressure.

Further, when the current wheel cylinder pressure Pm matches the control oil pressure Pc and needs to be held (hereinafter referred to as a holding mode), the brake fluid is turned off by closing the linear solenoid valves 35 _FL and 36 _FR. The cylinder 31 is held so as not to come off from the _FR side, and the pressure is held.

When the current wheel cylinder pressure Pm is higher than the control oil pressure Pc, that is, when pressure reduction is necessary (hereinafter referred to as pressure reduction mode), the pressure reducing linear solenoid valve 36 _FL is opened and the holding linear solenoid valve is opened. By closing the 35 _FR , a part of the brake fluid is returned to the reservoir 22 from the wheel cylinder 31 side to reduce the pressure.

  In the actuator 3 of FIG. 2, a linear solenoid valve is used for holding and decompressing, but control hydraulic pressure may be controlled by duty control using a switching solenoid valve. Further, the actuator for controlling the hydraulic pressure of the wheel cylinder 31 is not limited to the actuator 3 in FIG. 2, and may have other configurations and structures as long as the hydraulic pressure of the wheel cylinder 31 can be controlled. . Further, in the vehicle behavior control device, output control of an engine mounted on the vehicle can be performed by an engine ECU (not shown in FIG. 1).

  Next, the operation of the vehicle behavior control device of this embodiment will be described.

The vehicle behavior control device according to the present embodiment performs vehicle behavior control using at least the lateral acceleration sensor 44 and the yaw rate sensor 42. For example, as basic vehicle behavior control, the turning state of the vehicle is determined based on the steering angle of the steering wheel, the vehicle speed, the yaw rate of the vehicle, and the lateral acceleration of the vehicle, and the brake ECU 1 determines the wheel cylinders 31 _{FL to} 31 _{RR as} necessary. Is appropriately adjusted to control the behavior of the vehicle when turning.

  Further, the target yaw rate of the vehicle is calculated using the output of the lateral acceleration sensor 44, and the behavior control is started when the deviation between the target yaw rate and the output of the yaw rate sensor 42 exceeds the control start threshold value. For example, the target yaw rate Yrtg is calculated by calculating (θ / (n · 1) −Kh · GY) · V. θ is the steering angle, n is the number of calculation times, Kh is the stability factor, GY is the lateral acceleration of the vehicle, and V is the vehicle speed. Then, when | Yrtg−YR |> Thvsc is established, the drift-out suppression control is started. YR is the yaw rate of the vehicle and is based on the output of the yaw rate sensor 42. Thvsc is a control start threshold value.

  Further, the sensor abnormality is determined based on the outputs of the lateral acceleration sensor 44 and the yaw rate sensor 42, and the setting of the vehicle behavior control start threshold value Thvsc is changed in accordance with the sensor abnormality.

  3 and 4 show flowcharts of the control start threshold value setting process in the vehicle behavior control apparatus according to the present embodiment. As shown in S10 of FIG. 3, it is determined whether or not the absolute value of the lateral acceleration GY is smaller than the first fixing treatment threshold Thg1. The lateral acceleration GY is a lateral acceleration value based on the output of the lateral acceleration sensor 44. The first adhering treatment threshold value Thg1 is a set value that is set in the brake ECU 1 in advance.

  When the absolute value of the lateral acceleration GY is not smaller than the first fixing treatment threshold value Thg1 in S10, the yaw rate YR is set as the minimum value Yrmin and the maximum value Yrmax in the control start threshold value setting process (S24). Exit. The yaw rate YR is a yaw rate value based on the output of the yaw rate sensor 42. On the other hand, when the absolute value of the lateral acceleration GY is smaller than the first fixing treatment threshold Thg1 in S10, it is determined whether or not the lateral acceleration GY is larger than the maximum value Gymax (S12). The maximum value Gymax is the maximum value of the lateral acceleration in the control start threshold value setting process, and the maximum value of the lateral acceleration GY is set.

  When it is determined in S12 that the lateral acceleration GY is greater than the maximum value Gymax, the lateral acceleration GY (GY (n)) is set as the maximum value Gymax (S14). Then, the process proceeds to S22. On the other hand, when it is determined in S12 that the lateral acceleration GY is not greater than the maximum value Gymax, it is determined whether or not the lateral acceleration GY is smaller than the minimum value Gymin (S16). The minimum value Gymin is the minimum value of the lateral acceleration in the control start threshold value setting process, and the minimum value of the lateral acceleration GY is set.

  When it is determined in S16 that the lateral acceleration GY is smaller than the minimum value Gymin, the lateral acceleration GY (GY (n)) is set as the minimum value Gymin (S18). Then, the process proceeds to S22. On the other hand, when it is determined in S16 that the lateral acceleration GY is not smaller than the minimum value Gymin, the previous minimum value Gymin (n-1) is set as the minimum value Gymin, and the previous maximum value Gymax (n-1). ) Is set as the maximum value Gymax (S20). Then, the process proceeds to S22.

  In S22, it is determined whether or not the fluctuation range of the lateral acceleration GY is within a predetermined range. That is, it is determined whether or not a value obtained by subtracting the minimum value Gymin from the maximum value Gymax (Gymax−Gymin) is smaller than the second fixing treatment threshold Thg2. The second adhering treatment threshold value Thg2 is a set value set in advance in the brake ECU 1. When it is determined in S22 that the value obtained by subtracting the minimum value Gymin from the maximum value Gymax is not smaller than the second fixing treatment threshold Thg2, the process proceeds to S24.

  On the other hand, when it is determined that the value obtained by subtracting the minimum value Gymin from the maximum value Gymax is smaller than the second fixing treatment threshold Thg2, the process proceeds to S26 in FIG. 4 to determine whether the yaw rate YR is greater than the maximum value Yrmax. To be judged. The maximum value Yrmax is the maximum value of the yaw rate in the control start threshold value setting process, and the maximum value of the yaw rate YR is set.

  When it is determined in S26 that the yaw rate YR is greater than the maximum value Yrmax, the yaw rate YR (YR (n)) is set as the maximum value Yrmax (S28). Then, the process proceeds to S36. On the other hand, when it is determined in S26 that the yaw rate YR is not larger than the maximum value Yrmax, it is determined whether or not the yaw rate YR is smaller than the minimum value Yrmin (S30). The minimum value Yrmin is the minimum value of the yaw rate in the control start threshold value setting process, and the minimum value of the yaw rate YR is set.

  When it is determined in S30 that the yaw rate YR is smaller than the minimum value Yrmin, the yaw rate YR (YR (n)) is set as the minimum value Yrmin (S32). Then, the process proceeds to S36. On the other hand, when it is determined in S30 that the yaw rate YR is not smaller than the minimum value Yrmin, the previous minimum value Yrmin (n-1) is set as the minimum value Yrmin, and the previous maximum value Yrmax (n-1). Is set as the maximum value Yrmax (S34). Then, the process proceeds to S36.

  In S36, it is determined whether the fluctuation range of the yaw rate YR is wider than a predetermined range. That is, it is determined whether or not a value obtained by subtracting the minimum value Yrmin from the maximum value Yrmax (Yrmax−Yrmin) is greater than the yaw rate threshold value Thy. The yaw rate threshold value Thy is a set value set in advance in the brake ECU 1. When it is determined in S36 that the value obtained by subtracting the minimum value Yrmin from the maximum value Yrmax is not larger than the yaw rate threshold value Thy, Thvsc1 is set as the VSC control start threshold value Thvsc (S38). Thvsc1 is a VSC control start threshold value in a normal time without sensor abnormality, and is preset in the brake ECU 1 in advance.

  On the other hand, when it is determined in S36 that the value obtained by subtracting the minimum value Yrmin from the maximum value Yrmax is greater than the yaw rate threshold value Thy, the value obtained by subtracting the minimum value Yrmin from the maximum value Yrmax is determined as the VSC control start threshold value Thvsc. A corresponding value f (Yrmax-Yrmin) is set (S40). This f (Yrmax−Yrmin) is set to a value that is difficult to start control for Thvsc1, and for example, as shown in FIG. 5, a large value is set for Thvsc1. When a large value is set as the VSC control start threshold Thvsc in this way, the deviation between the target yaw rate value estimated from the wheel speed and the actual yaw rate YR is less likely to exceed the VSC control start threshold Thvsc. It becomes difficult to start control.

  As described above, according to the vehicle behavior control apparatus according to the present embodiment, the output fluctuation range (Gymax-Gymin) of the lateral acceleration sensor 44 is smaller than the second fixing treatment threshold value Thg2 (first fluctuation value), and When the output fluctuation range (Yrmax−Yrmin) of the yaw rate sensor 42 is larger than the yaw rate threshold value Thy (second fluctuation value), the behavior is larger than that when the output fluctuation range of the yaw rate sensor 42 is less than or equal to the yaw rate threshold value Thy. The behavior control start condition is changed by setting the control start threshold value Thvsc high so that the control is difficult to start. By changing the conditions so that the behavior control is difficult to start in this way, even if the lateral acceleration sensor 44 is stuck abnormally and the target yaw rate is calculated to be larger than that when the sensor is normal, the control is erroneously performed. It can be prevented from starting. Therefore, inappropriate vehicle behavior control can be prevented when there is an abnormality in operation of the sensor.

1 is a schematic configuration diagram of a vehicle behavior control device according to an embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram in the vehicle behavior control device of FIG. 1. It is a flowchart of the control processing in the vehicle behavior control apparatus of FIG. It is a flowchart of the control processing in the vehicle behavior control apparatus of FIG. It is explanatory drawing of the threshold value setting process in the control process of FIG.

Explanation of symbols

1 ... brake ECU, 2 ... hydraulic booster, 3 ... brake actuator, 15 _FL to 15 _RR ... each wheel, 16 _FL ~ 16 _RR ... wheel speed sensor, 11 ... brake pedal, 21 ... master cylinder, 22 ... reservoir, 23 ... Accumulator, 24 ... Pump, 25 ... Relief valve, 27, 28 ... Accumulator pressure sensor, 31 _{FL to} 31 _RR ... Wheel cylinder, 32, 33 ... Master pressure sensor, 34 _{FL to} 34 _RR ... Wheel cylinder pressure sensor, 35 _FL to 35 _RR : linear solenoid valve for holding, 36 _{FL to} 36 _RR : linear solenoid valve for pressure reduction, 37 to 40: switching solenoid valve, 42: yaw rate sensor, 44: lateral acceleration sensor, 46: steering angle sensor.

Claims (1)

In a vehicle behavior control apparatus that performs vehicle behavior control using at least a lateral acceleration sensor and a yaw rate sensor,
The output fluctuation range of the yaw rate sensor when the output fluctuation range of the lateral acceleration sensor is smaller than the first fluctuation value and the output fluctuation width of the yaw rate sensor is larger than the second fluctuation value in the same behavior state of the vehicle. Is to change the behavior control start condition so that the behavior control is less likely to be started compared to the case of the second fluctuation value or less,
The start condition of the behavior control is that the target yaw rate of the vehicle is calculated using the output of the lateral acceleration sensor, and the deviation between the target yaw rate and the output of the yaw rate sensor exceeds the control start threshold value,
The control start threshold is set to a constant value when the output fluctuation range of the yaw rate sensor is less than or equal to the second fluctuation value, and when the output fluctuation width of the yaw rate sensor is larger than the second fluctuation value. Is set to a value such that behavior control is less likely to start as the output fluctuation range of the yaw rate sensor increases.
A vehicle behavior control device.

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