JP2012121448A - Vehicle motion control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle motion control system capable of simply predicting reduction of vehicle stability.SOLUTION: The vehicle motion control system 1 has a control device 5 for performing vehicle motion control such as anti-rollover control and US/OS suppression control, on the basis of vehicle state quantities such as wheel speed, vehicle body speed, longitudinal acceleration and lateral acceleration, an actual yaw rate, a steering angle, an accelerator opening, and brake depression force. Further the control device 5 has a stability reduction prediction part 53 for predicting future reduction of vehicle stability based on current vehicle state quantities and a past control history including a history of vehicle state quantities and an execution history of vehicle motion control.

Description

  The present invention relates to a vehicle motion control system, and more particularly to a vehicle motion control system that can easily predict a decrease in vehicle stability.

  A general vehicle motion control system predicts a future decrease in vehicle stability (stability related to vehicle motion or behavior) from the current vehicle state quantity, and implements vehicle motion control using this prediction result. There is. As a conventional vehicle motion control system that employs such a configuration, a technique described in Patent Document 1 is known.

JP 2007-223494 A

  However, since the conventional vehicle motion control system uses a neural network to predict a future decrease in vehicle stability, the calculation involved in the prediction is complicated and requires a processing device that is heavy or expensive. There is a problem.

  Therefore, the present invention has been made in view of the above, and an object thereof is to provide a vehicle motion control system capable of easily predicting a decrease in vehicle stability.

  To achieve the above object, a vehicle motion control system according to the present invention includes a control device that performs vehicle motion control based on a vehicle state quantity, and the control device includes a current vehicle state quantity and a vehicle state quantity. And a past control history including a vehicle motion control execution history, and a stability reduction prediction unit that predicts a future reduction in vehicle stability.

  In the vehicle motion control system according to the present invention, the control device includes a set value changing unit that changes a set value related to vehicle motion control when a future decrease in vehicle stability is predicted. Is preferred.

  In the vehicle motion control system according to the present invention, the control device may include a preliminary control unit that performs preliminary control related to vehicle motion control when a future decrease in vehicle stability is predicted. preferable.

  In the vehicle motion control system according to the present invention, it is preferable that the control device includes a control history generation unit that generates a predetermined control history in which the vehicle state quantity is associated with whether or not the vehicle motion control is performed.

  In the vehicle motion control system according to the present invention, since a future decrease in vehicle stability is predicted using the past control history, for example, a configuration for predicting a future decrease in vehicle stability using a neural network and In comparison, there is an advantage that vehicle stability can be easily predicted without performing complicated calculations.

FIG. 1 is a configuration diagram showing a vehicle motion control system according to an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the vehicle motion control system shown in FIG. FIG. 3 is a flowchart showing the operation of the vehicle motion control system shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Vehicle motion control system]
FIG. 1 is a block diagram showing a vehicle motion control system according to an embodiment of the present invention. This figure schematically shows a configuration in which the vehicle motion control system is applied to a passenger car.

  The vehicle motion control system 1 suppresses the rollover or OS / US (oversteer / understeer) tendency of the vehicle 10 by controlling the motion or behavior of the vehicle 10 (hereinafter referred to as vehicle motion control). In this embodiment, the vehicle 10 adopts the FR (Front engine Rear drive) type, and the left rear wheel 11RL and the right rear wheel 11RR of the vehicle 10 are drive wheels of the vehicle 10, and the left front wheel 11FL and the right side The front wheels 11FR are the steering wheels of the vehicle 10.

  The vehicle motion control system 1 includes a driving force distribution control device 2, a braking force control device 3, a sensor unit 4, and a control device 5 (see FIG. 1).

  The driving force distribution control device 2 is a device that distributes the driving force to the left and right driving wheels 11 RR and 11 RL, and includes, for example, a control differential 21. In the driving force distribution control device 2, when the engine 12 generates driving force, the driving force is transmitted to the control differential 21 through the transmission 13, the propeller shaft 14 and the viscous coupling 15. Then, this driving force is distributed to the left and right drive shafts 22RR, 22RL by the control differential 21, and transmitted to the drive wheels 11RR, 11RL. At this time, the distribution ratio of the driving force with respect to each driving wheel 11RR, 11RL is controlled (driving force distribution control).

  The braking force control device 3 is a device that controls the braking force applied to the wheels 11FR to 11RL, and includes a hydraulic circuit 31, wheel cylinders 32FR to 32RL, a brake pedal 33, and a master cylinder 34. The hydraulic circuit 31 includes a reservoir, an oil pump, various valves, and the like (not shown). The braking force control device 3 applies a braking force to the wheels 11FR to 11RL as follows. That is, (1) during normal operation, when the brake pedal 33 is depressed by the driver, the depression amount is transmitted to the hydraulic circuit 31 via the master cylinder 34. The hydraulic circuit 31 adjusts the hydraulic pressures of the wheel cylinders 32FR to 32RL, so that the wheel cylinders 32FR to 32RL are driven to apply a braking force to the wheels 11FR to 11RL. On the other hand, at the time of (2) vehicle motion control, the target braking force for each wheel 11FR to 11RL is calculated based on the motion state of the vehicle, and the hydraulic circuit 31 is driven based on this target braking force, and each wheel cylinder 32FR to 32RL. Is controlled (braking force control).

  The sensor unit 4 is a unit that detects a vehicle state quantity. The sensor unit 4 detects, for example, wheel speed sensors 41FR to 41RL that detect wheel speeds Vw_FR to Vw_RL of the wheels 11FR to 11RL, a vehicle speed sensor 42 that detects a vehicle body speed Vv, and a longitudinal acceleration Gx of the vehicle 10. A longitudinal acceleration sensor 43, a lateral acceleration sensor 44 that detects the lateral acceleration Gy of the vehicle 10, a yaw rate sensor 45 that detects the actual yaw rate Yr of the vehicle 10, and a steering angle sensor (or steering wheel) that detects the steering angle δ of the vehicle 10. Angle sensor) 46, an accelerator opening sensor 47 for detecting the accelerator opening, and a brake pedal force sensor 48 for detecting a pedaling force on the brake pedal.

  The control device 5 is a device that performs various controls, and includes, for example, an ECU (Electrical Control Unit), various programs, and a memory. The control device 5 includes a main control unit 51 that comprehensively controls the operation of the vehicle motion control system 1, a control history generation unit 52 that generates a history (control history) related to vehicle motion control, which will be described later, and a future vehicle. A stability decrease prediction unit 53 that predicts a decrease in stability, a set value change unit 54 that changes a set value related to vehicle motion control, a preliminary control unit 55 that performs preliminary control related to vehicle motion control, A vehicle motion control unit 56 that performs vehicle motion control, and a storage unit 57 that stores various programs and data (for example, the above-described control history, threshold values k1 to k3 described later, setting values and control maps for vehicle motion control, etc.). And have. In the control device 5, the main control unit 51 determines the engine 12, the driving force distribution control device 2, and the braking force control device based on the output signal of the sensor unit 4 and various programs and data read from the storage unit 57. 3 is driven and controlled. Thereby, total driving force control, driving force distribution control, braking force control, etc. are performed, and vehicle motion control is realized.

  This vehicle motion control system 1 includes, for example, roll-over resistance control, US / OS (oversteer / understeer) suppression control, ABS (Antilock Brake System) control, brake assist control, TRC (Traction Control), VSC (Vehicle Stability Control) can be realized.

[Vehicle motion control]
2 and 3 are flowcharts showing the operation of the vehicle motion control system shown in FIG. In these drawings, FIG. 2 shows an overall flowchart of vehicle motion control, and FIG. 3 shows a specific example of vehicle stability reduction prediction in vehicle motion control.

  In this vehicle motion control system 1, a future decrease in vehicle stability (stability related to vehicle motion or behavior) is predicted from the current vehicle state quantity, and vehicle motion control is performed using this prediction result. Hereinafter, this vehicle motion control will be described (see FIG. 2).

  In step ST1, the current vehicle state quantity is acquired. The vehicle state quantity includes, for example, the wheel speeds Vw_FR to Vw_RL of the wheels 11FR to 11RL, the vehicle body speed Vv, the longitudinal acceleration Gx and the lateral acceleration Gy of the vehicle 10, the actual yaw rate Yr, the steering angle δ, the accelerator opening, the brake pedaling force, etc. Is included. For example, in this embodiment, the sensor unit 4 detects various vehicle state quantities while the vehicle is traveling, and the control device 5 acquires these vehicle state quantities as output signals of the sensor unit 4. Yes. The control device 5 may estimate these vehicle state quantities based on the output signal of the sensor unit 4. After this step ST1, the process proceeds to step ST2.

  In step ST2, a history (control history) related to past vehicle motion control is acquired. This control history includes at least a history of vehicle state quantities and an execution history of vehicle motion control. For example, in this embodiment, the control device 5 stores, as a control history, information associating presence / absence (operation result) of vehicle motion control (step ST7), which will be described later, with the vehicle state quantity at that time. 57. After this step ST2, the process proceeds to step ST3.

  In step ST3, it is determined whether or not there is a possibility that the vehicle stability will decrease in the future (vehicle stability decrease prediction). This determination is made based on the current vehicle state quantity acquired in step ST1 and the past control history acquired in step ST2. For example, an affirmative determination is made when at least one of the following conditions is satisfied: (1) vehicle motion control is performed within a predetermined period; and (2) the current vehicle state quantity satisfies a predetermined condition. Is called. Alternatively, an affirmative determination may be made when both of the conditions (1) and (2) are satisfied. If an affirmative determination is made in step ST3, the process proceeds to step ST4, and if a negative determination is made, the process proceeds to step ST6.

  In this embodiment, the vehicle stability decrease prediction (step ST3) is performed as follows (see FIG. 3).

  In step ST31, it is determined whether or not the vehicle motion control (step ST7) is performed within a predetermined period. As this predetermined period, for example, a period from the time 30 minutes before to the present is selected. If an affirmative determination is made in step ST31, the process proceeds to step ST4, and if a negative determination is made, the process proceeds to step ST32. That is, when vehicle motion control (step ST7) is performed within the past 30 minutes, an affirmative determination is immediately made.

  In step ST32, it is determined whether or not the current vehicle speed V is equal to or higher than a predetermined threshold k1 (V ≧ k1). The threshold value k1 is set to 30 [km / h], for example. If an affirmative determination is made in step ST32, the process proceeds to step ST33, and if a negative determination is made, the process proceeds to step ST6.

  In step ST33, it is determined whether or not the current steering angle δ is equal to or greater than a predetermined threshold k2 (δ ≧ k2). This threshold value k2 is set to 300 [deg / s], for example. If an affirmative determination is made in step ST33, the process proceeds to step ST4. If a negative determination is made, the process proceeds to step ST34.

In step ST34, it is determined whether or not the current lateral acceleration Gy is equal to or greater than a predetermined threshold k3 (Gy ≧ k3). This threshold value k3 is set to 5.0 [m / s ² ], for example. Note that determination using the yaw rate β may be performed instead of the lateral acceleration Gy. If an affirmative determination is made in step ST34, the process proceeds to step ST4. If a negative determination is made, the process proceeds to step ST6.

  In the vehicle stability decrease prediction step ST3, the control device 5 may change the threshold values k1 to k3 based on the control history.

  In step ST4, a set value for vehicle motion control is changed. For example, when the control device 5 changes the threshold for the control start condition, the vehicle motion control can be advanced (early start). Further, for example, the control device 5 can increase the effectiveness of the vehicle motion control by changing the control amount of the vehicle motion control (for example, increasing the target deceleration, increasing the target moment, etc.). Thereby, when there is a possibility that the vehicle stability may be lowered in the future (affirmative determination in step ST3), the vehicle motion control can be appropriately performed according to the traveling state of the vehicle. After this step ST4, the process proceeds to step ST5.

  In step ST5, preliminary control related to vehicle motion control is performed. For example, by performing precharge control, it is possible to advance vehicle motion control. Thereby, the delay of vehicle motion control can be suppressed. After this step ST5, the process proceeds to step ST6.

  In step ST6, it is determined whether or not the vehicle motion control start condition is satisfied. This start condition is appropriately set according to the contents of the vehicle motion control. In this embodiment, the control device 5 performs the determination based on the output signal from the sensor unit 4 and the threshold value for the control start condition read from the storage unit 57. If an affirmative determination is made in step ST6, the process proceeds to step ST7, and if a negative determination is made, the process proceeds to step ST8.

  In step ST7, vehicle motion control is started. At this time, if a decrease in vehicle stability is predicted from the vehicle state quantity (affirmative determination in step ST3), a change in set value (step ST4) and preliminary control (step ST5) for vehicle motion control are performed. Since it is performed in advance, vehicle motion control is appropriately performed. Thereby, stabilization of vehicle motion is realized. After step ST7, the process proceeds to step ST8.

  In step ST8, the control history is updated. For example, in this embodiment, the control device 5 generates update information in which the current vehicle state quantity acquired in step ST1 and the presence / absence (operation performance) of the vehicle motion control in step ST7 are associated, The control history is updated using this update information and stored in the storage unit 57. After this step ST8, the process is terminated.

[effect]
As described above, the vehicle motion control system 1 includes the control device 5 that performs vehicle motion control (step ST7) based on the vehicle state quantity (see FIGS. 1 and 2). Further, the control device 5 predicts a future decrease in vehicle stability based on the current vehicle state quantity and the past control history including the history of the vehicle state quantity and the execution history of the vehicle motion control (step ST3). ) Having a stability decrease prediction unit 53.

  In such a configuration, since a future decrease in vehicle stability is predicted using the past control history, for example, compared with a configuration that predicts a future decrease in vehicle stability using a neural network, it is more complicated. There is an advantage that vehicle stability can be easily predicted without performing calculations.

  In the vehicle motion control system 1, the control device 5 changes a set value for vehicle motion control (step ST4) when a future decrease in vehicle stability is predicted (positive determination in step ST3). There is a set value changing unit 54 (see FIGS. 1 and 2). Thereby, it is possible to advance the vehicle motion control, and there is an advantage that the effectiveness of the vehicle motion control can be improved.

  Further, in this vehicle motion control system 1, the control device 5 performs preliminary control (step ST5) related to vehicle motion control when a future decrease in vehicle stability is predicted (positive determination in step ST3). Has a preliminary control unit 55 (see FIGS. 1 and 2). Accordingly, there is an advantage that the vehicle motion control can be advanced.

  Moreover, in this vehicle motion control system 1, the control apparatus 5 has the control history production | generation part 52 which produces | generates the predetermined | prescribed control history which linked | related the vehicle state quantity and the presence or absence of implementation of vehicle motion control (step ST8). In such a configuration, a past control history can be updated by newly generating and storing a control history. Thereby, there exists an advantage which can improve the prediction precision of a future vehicle stability fall.

  As described above, the vehicle motion control system according to the present invention is useful in that a decrease in vehicle stability can be easily predicted.

  DESCRIPTION OF SYMBOLS 1 Vehicle motion control system, 2 Driving force distribution control apparatus, 21 Control differential, 22RR-22RL Drive shaft, 3 Braking force control apparatus, 31 Hydraulic circuit, 32FR-32RL Wheel cylinder, 33 Brake pedal, 34 Master cylinder, 4 Sensor unit , 41FR to 41RL, wheel speed sensor, 42 vehicle speed sensor, 43 longitudinal acceleration sensor, 44 lateral acceleration sensor, 45 yaw rate sensor, 46 steering angle sensor, 47 accelerator opening sensor, 48 brake pedal force sensor, 5 control device, 51 main control unit , 52 Control history generation unit, 53 Stability reduction prediction unit, 54 Set value change unit, 55 Preliminary control unit, 56 Vehicle motion control unit, 57 Storage unit, 10 vehicle, 11FR to 11RL wheels, 12 engine, 13 transmission, 14 Propeller Shift, 15 viscous coupling

Claims (4)

A control device that performs vehicle motion control based on the vehicle state quantity; and
The control device predicts a decrease in future vehicle stability based on a current vehicle state quantity and a past control history including a history of the vehicle state quantity and an execution history of vehicle motion control. The vehicle motion control system characterized by having a part.   2. The vehicle motion control system according to claim 1, wherein the control device includes a set value changing unit configured to change a set value related to vehicle motion control when a future decrease in vehicle stability is predicted.   The vehicle motion control system according to claim 1, wherein the control device includes a preliminary control unit that performs preliminary control related to vehicle motion control when a future decrease in vehicle stability is predicted.   The vehicle control system according to any one of claims 1 to 3, wherein the control device includes a control history generation unit that generates a predetermined control history that associates a vehicle state quantity and whether or not to perform vehicle motion control. .

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