JP2005059655A - Conjoint control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately perform a control response to a driver's intention based on the driver's braking operation and steering operation during a vehicle stabilization control. <P>SOLUTION: The device performs a braking applying control applying the braking force relative to each wheel, and is equipped with a braking applying control means (CC) which performs the vehicle stabilization control by controlling the braking force relative to each wheel based on the vehicle state. When the brake operation by the driver is detected with the braking force applying means during the vehicle stabilization control, it is switched to the braking force applying means, and when a steering increase operation by the driver is detected, it is switched to the braking force applying control. Additionally, when the steering increase operation is detected during the braking force applying control, it is switched to the vehicle stabilization control. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vehicle motion control device, and in particular, controls braking force on each wheel according to the vehicle state and performs vehicle stabilization control, thereby suppressing excessive oversteer and / or understeer during vehicle motion. The present invention relates to a vehicle motion control device that maintains the stability of the vehicle.

  As a vehicle motion control device, various devices have been proposed that control the output of an internal combustion engine and / or control the braking force for each wheel in accordance with the vehicle state. Among these, as an example of a device that controls the braking force on each wheel according to the vehicle state and performs vehicle stabilization control, for example, Patent Literature 1 below discloses a vehicle braking force control device.

  In Patent Document 1, “Vehicle behavior control and slip control are possible, and a situation such as a decrease in turning performance in the case where both controls operate simultaneously in a fast steering operation state is prevented. An object of the present invention is to provide a braking force control device for a vehicle that can perform braking force control adapted to the turning ability when it is necessary. Based on the output of the steering angular velocity detection means, when the steering speed is high, the priority control means preferentially performs the first braking force control for controlling the braking force so that the vehicle behavior becomes the target characteristic. I am trying to make it. As a result, it is described that the vehicle behavior control is preferentially executed at the time of control in a state where the steering speed is high, and control that well corresponds to the driver's intention is made possible.

JP-A-4-243651

  In the device described in Patent Document 1, the steering angular velocity is used as an index corresponding to the driver's intention during the vehicle behavior control. However, in order to perform the control in response to the driver's intention during the vehicle behavior control. The steering angular velocity alone is not sufficient. For example, when the driver operates the brake pedal while understeer suppression control is being performed as vehicle stabilization control, it can be estimated that the driver has determined that the physical limit by vehicle stabilization control has been exceeded. Therefore, it is necessary to perform a control that can realize the braking operation.

  In addition, when the driver performs a steering turning operation while the vehicle stabilization control is being performed, it may be estimated that the driver has determined that the physical limit by the vehicle stabilization control has been exceeded. Therefore, it is necessary to perform control so that the braking operation can be realized. Here, the steering turning-up operation is, for example, when the driver is turning while holding the steering wheel at a constant steering angle, for example, when the vehicle has an understeer tendency such that the vehicle shifts outward in the turning direction. The driver refers to operating the steering wheel so as to increase the steering angle in order to offset this.

  Further, when the driver performs a braking operation during the vehicle stabilization control and the braking force is applied, it is estimated that the driver tried to avoid danger when the driver performed a steering turning operation. In this case, it is desirable to shift to vehicle stabilization control (understeer suppression control).

  Accordingly, it is an object of the present invention to provide a vehicle motion control device that can appropriately perform control in accordance with the driver's intention based on the driver's brake operation and steering operation during vehicle stabilization control. .

  To achieve the above object, according to a first aspect of the present invention, there is provided a vehicle motion control apparatus for controlling a braking force for each wheel according to a vehicle state and performing vehicle stabilization control. Vehicle state quantity detection means for detecting a state quantity and braking force application control for applying a braking force to each wheel, and controlling the braking force for each wheel based on the detection result of the vehicle state quantity detection means Brake force control means for performing vehicle stabilization control, brake operation detection means for detecting a brake operation by the driver of the vehicle, and steering operation detection means for detecting at least a steering addition operation by the driver of the vehicle. The braking force control means is used for braking force application control when the brake operation detection means detects a brake operation during vehicle stabilization control. With changing, which is constituted to switch the braking force application control when the vehicle stability control the steering operation detecting means during detects the steering turning-increasing operations.

  The braking force control means is further configured to switch to vehicle stabilization control when the steering operation detection means detects a steering turning increase operation during the braking force application control. It is better to shift to understeer suppression control.

  The vehicle state quantity detection means includes a yaw index detection means for detecting an actual yaw index of the vehicle, and further sets a target yaw index setting for setting a target yaw index for the vehicle. And a yaw index deviation calculating means for calculating a deviation between the target yaw index set by the target yaw index setting means and the actual yaw index detected by the yaw index detecting means. According to the yaw index deviation calculated by the means, the braking force control means can control the braking force for each wheel to perform vehicle stabilization control. The yaw index includes the yaw rate of the vehicle, which can be detected directly by the yaw rate, but can be calculated based on the longitudinal acceleration and lateral acceleration of the vehicle.

  As the braking force control means, for example, a hydraulic system communicating with a wheel cylinder mounted on each wheel of the vehicle is divided into two hydraulic systems each including a pair of wheel cylinders, and a pair of hydraulic systems is connected. A hydraulic pressure adjusting device is interposed between the wheel cylinder and the master cylinder, and the brake hydraulic pressure is adjusted according to the vehicle state quantity with one wheel cylinder of each hydraulic pressure system as a control target. It can comprise so that vehicle stabilization control may be performed.

  Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle motion control apparatus according to claim 1, when the brake operation detecting means detects the brake operation during the vehicle stabilization control, the control is switched to the braking force application control and the steering operation is detected during the vehicle stabilization control. Since the means switches to the braking force application control when the steering turning operation is detected, when the driver operates the brake pedal and the steering wheel during the vehicle stabilization control, the operation is based on these operations. Thus, it is possible to perform an appropriate braking force control in response to the driver's intention.

  Further, if the braking force control means is configured as described in claim 2, when the driver operates the brake pedal during the vehicle stabilization control and the braking force application control is performed, the driver When the steering wheel is operated and the steering operation detecting means detects an operation for increasing the steering, the vehicle stabilization control is performed, so that it is possible to immediately respond to the driver's risk avoidance operation.

  Further, if the vehicle state quantity detection means is configured as described in claim 3, it is possible to easily control the braking force control means and appropriately control the braking force applied to each wheel.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of a motion control apparatus according to an embodiment of the present invention, which includes a hydraulic pressure adjustment device BC that controls a braking force applied to each wheel of a vehicle. In FIG. 1, wheel cylinders Wfl, Wfr, Wrl, Wrr are mounted on wheels FL, FR, RL, RR, respectively, and a hydraulic pressure adjusting device BC is connected to these wheel cylinders Wfl. Since the hydraulic pressure adjusting device BC can be configured in the same manner as a conventional general device including a plurality of electromagnetic valves, the illustration thereof is omitted. Note that the wheel FL indicates the front left wheel as viewed from the driver's seat, the wheel FR indicates the front right side, the wheel RL indicates the rear left side, and the wheel RR indicates the rear right wheel.

  The wheels FL and FR in front of the vehicle are steered by the operation of the steering wheel SW by the driver, and the steering angle is detected by the steering angle sensor SS. A vehicle body speed sensor VS is provided to detect the vehicle body speed, and the vehicle body deceleration can be obtained by differentiating it. The vehicle body speed may be estimated and calculated based on the wheel speed detected by a wheel speed sensor (not shown) provided on each wheel. Further, a yaw rate sensor YS for detecting the yaw rate of the vehicle is provided, and the yaw rate as the yaw index is directly detected. That is, the yaw index includes a yaw angle that is a rotation angle around the vertical axis passing through the center of gravity of the vehicle and a yaw rate that is the yaw angular velocity. In this embodiment, the yaw rate is used as the yaw index. A longitudinal acceleration sensor (not shown) for detecting the longitudinal acceleration of the vehicle, a lateral acceleration sensor (not shown) for detecting the lateral acceleration of the vehicle, and the like may be provided.

  Further, a stop switch (not shown) that is turned on / off in response to the operation of the brake pedal BP is provided, and these detection signals are input to the electronic control unit ECU. The electronic control unit ECU performs traction control, anti-skid control, and the like in addition to the above-described stabilization control, and includes a CPU, ROM, and RAM (not shown) for these controls.

  In the electronic control unit ECU, as shown in FIG. 1, target yaw index setting means TY for setting a target yaw index (target yaw rate) based on a steering angle and a vehicle body speed as a control target for performing vehicle stabilization control; The actual yaw index detecting means AY for detecting the actual yaw index (actual yaw rate) of the vehicle, and the deviation between the target yaw index set by the target yaw index setting means TY and the actual yaw index detected by the actual yaw index detecting means AY is calculated. The yaw deviation calculating means DY is configured. Then, the hydraulic pressure adjusting device BC is controlled by the braking force control means CC so that the yaw deviation (yaw rate deviation) calculated by the yaw deviation calculating means DY becomes substantially zero. The braking force of the inner rear wheel) is adjusted, and so-called diagonal control is performed.

  Further, in the electronic control unit ECU, for example, a brake operation detecting means BS for detecting presence / absence of operation of the brake pedal BP by the driver based on an on / off signal of the above-described stop switch (not shown), and at least steering by the driver The steering operation detecting means ST for detecting an increase operation of the vehicle is configured, and when the brake operation detecting means BS detects the brake operation during the vehicle stabilization control, it is switched to the braking force application control and the vehicle stabilization control is being performed. On the other hand, when the steering operation detecting means ST detects the steering turning increase operation, the control is switched to the braking force application control. In addition, the specific aspect of this braking force provision control is mentioned later.

  In the present embodiment configured as described above, various controls are performed by the electronic control unit ECU, but a main routine for processing these is common and thus omitted. FIG. 2 shows a sub-steer suppression control subroutine performed as vehicle stabilization control. Steps 101 to 108 are repeated at predetermined intervals as part of the main routine. First, in step 101, it is detected whether or not the driver has operated the brake pedal BP. When the brake pedal BP is not operated, the process proceeds to step 102, and whether or not the steering wheel SW has been operated to be increased by the driver. Is determined. If the steering wheel SW has not been increased, the routine proceeds to step 103 where normal understeer suppression control is performed.

  In the present embodiment, in one hydraulic system, the front outer wheel FR (or FL) is set as a non-control wheel based on the turning direction of the vehicle, and the rear inner wheel positioned diagonally with respect thereto. A braking force is applied to RL (or RR), and diagonal control is performed. That is, the wheel cylinder hydraulic pressure of the front outer wheel FR (or FL) is maintained, and the wheel cylinder hydraulic pressure of the wheel cylinder Wrl (or Wrr) of the rear inner wheel RL (or RR) is controlled. The control status of the understeer suppression control performed in steps 107 and 108 in FIG. 2 including the above step 103 is shown in the time charts in FIGS. 3 to 5. FIG. 3 shows the braking force control in the following steps. It demonstrates referring thru | or the hydraulic-pressure control state shown in FIG.

As shown in FIG. 3 to FIG. 5A, in the present embodiment, two types of targets are based on the vehicle state quantities such as the wheel speed Vw, the yaw rate Ya, the lateral acceleration Gy, the steering angle As, and the vehicle body speed V. The yaw rate Yto and the target yaw rate Ytu are set as follows. First, the target yaw rate Yto is set to Yto = Gy / V based on the lateral acceleration Gy and the vehicle body speed V. The target yaw rate Ytu is set as follows based on the lateral acceleration Gy, the steering angle As, the vehicle body speed V, and the like.
Ytu = Gy / V + C [(V · As) / {N · L · (1 + K · V ² )} − Gy / V]
Here, N is a steering gear ratio, L is a wheel base, K is a stability factor, and C is a weighting factor.

  Then, the yaw rate deviation ΔYto (= Yto−Ya) between the actual yaw rate Ya detected by the yaw rate sensor YS and the target yaw rate Yto, and the yaw rate deviation ΔYtu (= Ytu−Ya) with the target yaw rate Ytu are calculated. On the basis of the former yaw rate deviation ΔYto, the wheel cylinder hydraulic pressure on the outer front side of the vehicle is controlled as shown in FIG. 4 and FIG. 5C, whereas on the basis of the latter yaw rate deviation ΔYtu, the wheel on the rear inner side of the vehicle is controlled. The cylinder hydraulic pressure is controlled as shown in FIG. 3B to 5B show the master cylinder hydraulic pressure output from the master cylinder (not shown) in response to the operation of the brake pedal BP.

  Thus, in step 103 in FIG. 2, for example, when understeer suppression control starts at the time ta in FIG. 3, the wheel cylinder hydraulic pressure inside the vehicle rear is controlled to increase as shown in FIG. A braking force is applied to the rear inner wheel, and understeer suppression control by diagonal control is performed. During understeer suppression control for the control wheels from time ta to time tb in FIG. 3, the wheel cylinders of the non-control wheels are held as shown in FIG. It is good also as controlling suitably according to the relationship with a cylinder hydraulic pressure.

  On the other hand, when it is determined in step 101 of FIG. 2 that the brake pedal BP is operated, the process proceeds to step 104, and it is determined whether or not understeer suppression control has been performed before the brake operation. If so, in other words, if a brake operation is performed during the understeer suppression control, the process proceeds to step 105, where the understeer suppression control is terminated, and after the time tb in FIG. A master cylinder hydraulic pressure (Pm) is applied to each wheel cylinder, and a braking force is applied to all wheels. That is, the braking operation is prioritized and the braking force application control is performed.

  In step 104 of FIG. 2, the understeer suppression control is not being performed before the brake operation, but the brake operation is being performed, and the master cylinder hydraulic pressure (Pm) is applied to all the wheel cylinders as shown in FIGS. When understeer suppression control is started at the time ta, as shown in FIG. 4D, the wheel cylinder hydraulic pressure inside the vehicle rear is controlled based on the yaw rate deviation ΔYtu = Ytu−Ya). In this state, it is further determined in step 106 in FIG. 2 whether or not the steering wheel SW has been operated to be increased, and if the steering wheel SW has not been increased, the process proceeds to step 103, where The wheel cylinder hydraulic pressure is controlled as shown in (D) until time tc in FIG. 4, and normal understeer suppression control is performed.

  On the other hand, if it is determined in step 106 in FIG. 2 that the steering wheel SW has been operated to increase (at time tc in FIG. 4), the process proceeds to step 107, and as shown in FIG. The wheel cylinder hydraulic pressure is reduced so that the braking force applied to the outer front wheels of the vehicle is reduced. In this case, the wheel cylinder hydraulic pressure on the outer front side of the vehicle is controlled based on the yaw rate deviation ΔYto (= Yto−Ya), whereas the wheel cylinder hydraulic pressure on the inner rear side of the vehicle becomes the yaw rate deviation ΔYtu as described above. Based on this control, adjustment is performed as shown in FIG. That is, in step 107, the stabilization control is prioritized. At this time, the wheel cylinder hydraulic pressure at the vehicle rear inner side is a value obtained by adding the hydraulic pressure corresponding to the control amount to the master cylinder hydraulic pressure Pm as shown in FIG. However, by using a proportional differential pressure valve in place of the so-called cut-off valve that constitutes the hydraulic pressure adjusting device BC, such hydraulic pressure adjustment is possible.

  On the other hand, if it is determined in step 102 in FIG. 2 that the steering wheel SW has been operated to increase (at time tc in FIG. 5), the process proceeds to step 108, and the wheel cylinder on the outer front side of the vehicle as shown in FIG. Control is performed so that the hydraulic pressure is increased and braking force is applied to the wheels on the front outer side of the vehicle. That is, the braking operation is prioritized and the braking force application control is performed. Also in this case, the wheel cylinder hydraulic pressure outside the vehicle front is controlled based on the yaw rate deviation ΔYto, whereas the wheel cylinder hydraulic pressure inside the vehicle rear is controlled based on the yaw rate deviation ΔYtu, as shown in FIG. It is adjusted as shown in

It is a block diagram which shows one Embodiment of the movement control apparatus of the vehicle of this invention. It is a flowchart which shows the process of the understeer suppression control in one Embodiment of this invention. In one Embodiment of this invention, it is a graph which shows an example of the state of the wheel cylinder hydraulic pressure of the wheel of a yaw rate, a master cylinder hydraulic pressure, a back inner side, and a front outer side when it brakes during understeer suppression control. In one embodiment of the present invention, understeer suppression control is performed in a state where the brake pedal is operated, yaw rate when the steering is increased, master cylinder hydraulic pressure, wheels on the rear inner and front outer wheels It is a graph which shows an example of the state of cylinder hydraulic pressure. The graph which shows an example of the state of the wheel cylinder hydraulic pressure of the yaw rate, master cylinder hydraulic pressure, the back inner side, and the front outer wheel when steering addition operation is performed during understeer suppression control in one embodiment of the present invention. It is.

Explanation of symbols

BP Brake pedal SW Steering wheel SS Steering angle sensor YS Yaw rate sensor BC Hydraulic pressure control unit ECU Electronic control unit FR, FL, RR, RL Wheel Wfr, Wfl, Wrr, Wrl Wheel cylinder

Claims (3)

  In a vehicle motion control device that controls a braking force for each wheel according to a vehicle state and performs vehicle stabilization control, a vehicle state amount detecting unit that detects a state amount of the vehicle, and a braking force for each wheel are applied. The braking force application control is performed, and the braking force control means for controlling the braking force for each wheel based on the detection result of the vehicle state quantity detection means to perform vehicle stabilization control, and the braking operation by the driver of the vehicle. A brake operation detecting means for detecting; and a steering operation detecting means for detecting at least a steering turning operation by a driver of the vehicle. The braking force control means is configured so that the brake operation detecting means is operated during vehicle stabilization control. When the brake operation is detected, the control is switched to the braking force application control, and the steering operation detection means is operated during the vehicle stabilization control. Ing motion control apparatus for a vehicle when detecting the additional steering operation, characterized by being configured to switch the braking force application control.   2. The vehicle according to claim 1, wherein the braking force control unit is configured to switch to vehicle stabilization control when the steering operation detection unit detects a steering turning increase operation during braking force application control. 3. Motion control device. The vehicle state quantity detection means comprises a yaw index detection means for detecting an actual yaw index of the vehicle, and a target yaw index setting means for setting a target yaw index for the vehicle, and the target yaw index setting means The yaw index deviation calculating means for calculating a deviation between the target yaw index set by the yaw index detecting means and the actual yaw index detected by the yaw index detecting means, and according to the yaw index deviation calculated by the yaw index deviation calculating means, The vehicle motion control device according to claim 1 or 2, wherein the braking force control means controls the braking force on each wheel to perform vehicle stabilization control.

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