JP2006117154A - Motion controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provided a motion controller capable of adequately performing speed reduction control according to a degree of urgency representing the extent of the possibility that a vehicle becomes unstable. <P>SOLUTION: A grip degree monitoring means M2 monitors a gripping degree representing the extent of lateral gripping of wheels and a start decision means M3 compares the gripping degree with a control start threshold to decide whether a speed reduction control means M1 starts performing speed reduction control of the vehicle according to the comparison result. Further, an urgency degree estimating means M4 estimates the degree of urgency representing the extent of the possibility that the vehicle becomes unstable based upon at least one of an operation state of the driver of the vehicle and the driving state of the vehicle (for example, the rate of variation of the gripping degree), and a threshold setting means M5 sets the control start threshold according to the degree of urgency. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vehicle motion control device that performs vehicle stabilization control in accordance with the degree of grip in the lateral direction of a tire.

  With regard to a vehicle motion control device, Patent Document 1 described later aims to accurately estimate a grip degree representing a degree of a grip in a lateral direction with respect to a wheel and appropriately control a vehicle motion based on the grip degree. The front wheel self-aligning torque is estimated based on the steering torque or the steering force, the front wheel side force (or front wheel slip angle) is estimated based on the vehicle state quantity, and based on the change in the self-aligning torque relative thereto, An apparatus for estimating a grip degree of a front wheel and a vehicle motion control apparatus including the apparatus are disclosed.

  Further, Patent Document 2 discloses a vehicle motion control device that can perform vehicle stability control from a normal range before reaching a friction limit range. Based on the change of the lining torque, the grip degree of the front wheel is estimated, the first control means for performing the closed loop control (grip degree control) based on the grip degree, and the target vehicle behavior is set based on the state quantity of the vehicle. Second control means for performing closed-loop control (vehicle behavior control) based on a deviation between the actual vehicle behavior and the vehicle behavior, and in the normal region before the friction limit, grip degree control is performed according to the driver's operation to stabilize the vehicle. A device is disclosed that maintains vehicle performance and performs vehicle behavior control when the vehicle enters a limit range despite execution of this control, and ensures vehicle stability.

  In Non-Patent Document 2 described later, an index focusing on characteristics of a wheel tire (air rubber tire) is described. In other words, the tire margin until the cornering force of the tire reaches the limit, in other words, the parameter that expresses how much force is generated with respect to the maximum force that the tire can generate by the margin to the limit. Is defined as “grip margin”. It is explained that this is obtained based on the self-aligning torque and the reference self-aligning torque, and a specific calculation method is explained for each, so that the explanation is omitted here.

  Further, Non-Patent Document 2 discloses a result of studying improvement in performance of vehicle stabilization control by applying the above-described grip margin to control of a steering system and a braking system. That is, by using the grip margin, it is possible to start the vehicle stabilization control from a state where the tire is approaching the limit region but still has a margin. As an application example to a steering system, an example in which the estimation result of the grip margin is used for variable control of the overall steering gear ratio is disclosed. As an application example to the braking system, deceleration control according to the grip margin is disclosed. Further, control that integrates control of the steering system and the brake system is described as a future study subject.

  As described above, as for the characteristics of the wheel tires taken up in Non-Patent Document 2 as described above, also in Non-Patent Document 1, the types of wheels include wheels with air rubber tires, wheels with solid rubber tires, iron wheels, The relationship between the side slip angle and the cornering force is shown for each wheel, and it is explained that the maximum value of the force that can be generated by the wheel with the air rubber tire is large. A wheel with a pneumatic rubber tire is called a “tire”, which explains the force acting on the tire with a side slip and its property, and also describes the self-aligning torque.

JP 2003-31465 A JP 2003-31319 A Masato Abe, “Motor Movement and Control”, Sankaido Co., Ltd., Second Printing, May 31, 1994 Yuji Muragishi and 7 others, “Grip state estimation based on SAT and its application” Japan Society for Automotive Technology, Spring Academic Lecture, May 22, 2003

  The grip margin described in Non-Patent Document 2 described above corresponds to the grip degree indicating the degree of grip in the lateral direction with respect to the wheels described in Patent Document 1 described above, and in the following, these are collectively referred to as the grip degree. . In particular, regarding the control based on the grip degree disclosed in Patent Document 1, there is room for further study in terms of the deceleration control corresponding to the degree of urgency that represents the degree of possibility that the vehicle becomes unstable. In this connection, Patent Document 2 proposes a combination with vehicle behavior control, but does not mention deceleration control according to the degree of urgency. The deceleration control in this case means control for decelerating the vehicle regardless of the driver's braking operation, and as means for that, in addition to the brake fluid pressure control device, the engine throttle control device or fuel injection control. Devices, shift control devices, and the like.

  As described above, when the vehicle stabilization control is performed by decelerating by the deceleration control according to the grip degree of the tire, the stabilization effect is great, but a sense of discomfort may occur depending on the operation of the vehicle driver. I can't deny that. For example, control intervention based on the degree of grip at the time of deceleration control should be limited to a case where a tire or a vehicle is expected to reach a limit if nothing is done thereafter, and control based on the operation state of the vehicle driver is desirable. . In particular, deceleration control according to the degree of urgency described above is desired, and thereby effective stabilization control with less discomfort can be realized.

  Therefore, the present invention can appropriately perform deceleration control in accordance with the degree of urgency indicating the degree of possibility that the vehicle becomes unstable in the vehicle motion control device that performs vehicle stabilization control based on the grip degree of the tire. It is an object to provide a motion control device.

  In order to solve the above-described problem, the present invention provides a vehicle motion control apparatus that performs vehicle stabilization control based on a grip degree that represents a margin in a lateral direction of a tire with respect to a traveling road surface. A deceleration control means for controlling the deceleration of the vehicle, a grip degree monitoring means for monitoring the grip degree, a grip degree detected by the grip degree monitoring means is compared with a control start threshold value, and based on a comparison result, the deceleration Based on at least one of an operation state of a driver of the vehicle and an operation state of the vehicle, a degree of possibility that the vehicle becomes unstable based on start determination unit for determining start of deceleration control of the vehicle by the control unit The degree of urgency estimation means for estimating the degree of urgency to be represented, and the threshold setting means for setting the control start threshold value according to the degree of urgency estimated by the degree of urgency estimation means Than it is.

  The urgency degree estimation means may be configured to estimate the urgency degree based on a change rate of the grip degree detected by the grip degree monitoring means.

  Further, in the motion control device according to claim 1, as described in claim 3, the motion control apparatus includes a steering operation angle detection unit that detects a steering operation angle of a driver of the vehicle, and the degree of urgency estimation unit includes: The degree of urgency may be estimated based on at least one of a steering operation angle detected by the steering operation angle detection means and an operation angular velocity that is a change rate thereof.

  Alternatively, in the motion control device according to claim 1, as described in claim 4, the motion control device includes a brake operation amount detection unit that detects a brake operation amount of a driver of the vehicle, and the degree of urgency estimation unit includes: The degree of urgency may be estimated based on at least one of the brake operation amount detected by the brake operation amount detection means and the brake operation speed as the rate of change.

  Further, in the motion control device according to claim 1, as described in claim 5, at least one of a lateral acceleration, a yaw rate, a side slip angle, and a roll angle as an index indicating the driving state of the vehicle is provided. Vehicle state detection means for detecting, and the degree of urgency estimation means estimates the degree of urgency based on at least one of the indices indicating the driving state of the vehicle detected by the vehicle state detection means or a change rate thereof. You may comprise.

  Further, in the motion control device according to any one of claims 1 to 5, as described in claim 6, the deceleration control means includes the grip degree detected by the grip degree monitoring means and the threshold value setting. It can be configured to set at least one of the target deceleration and the deceleration control amount in accordance with the deviation from the control start threshold set by the means.

  Thus, according to the motion control apparatus of the first aspect, it is possible to appropriately start control according to the degree of urgency estimated based on at least one of the operation state of the vehicle driver and the driving state of the vehicle. Since the value can be set, the degree of urgency is an indicator that indicates whether the vehicle is likely to become unstable in the near future, that is, whether the vehicle driver is in an urgent state. Accordingly, the control start threshold value can be set. For example, it is estimated that the degree of urgency is greater as the vehicle driver is more likely to enter an unstable state, and the control start threshold is set in a direction in which deceleration control is more likely to start. . Conversely, when it is determined that the vehicle driver is traveling with some margin, the degree of urgency is estimated to be small, and the control start threshold value is set in a direction in which deceleration control is difficult to start. As a result, control in accordance with the feeling of the vehicle driver is performed.

  If the degree of urgency estimating means is configured as described in claims 2 to 4, the degree of urgency can be estimated easily and appropriately. For example, according to the degree-of-impression estimation means according to claim 2, the greater the change rate of the degree of grip, the more quickly the tire grip is lost and tends to become unstable. be able to. On the other hand, according to the degree of urgency estimation means described in claim 3, since the vehicle tends to become unstable as the steering operation angle or its speed increases, the degree of urgency can be estimated to be large. . According to the degree of urgency estimation means according to claim 4, the greater the amount of brake operation or its speed by the deceleration operation of the vehicle driver, the more the vehicle is decelerated and the vehicle tends to become stable. Can be estimated.

  Further, if the degree of urgency estimation means is configured as described in claim 5, the degree of urgency can be estimated using various detection signals, so that the detection signals provided to other control devices can be diverted. can do.

  In the motion control device according to any one of claims 1 to 5, as described in claim 6, the deceleration control means is configured to set a target deceleration and a deceleration control amount according to a deviation between a grip degree and a control start threshold value. At least one of them can be set. For example, if the target deceleration or deceleration control amount is set to increase according to the deviation, the deceleration control amount can be reduced immediately after the start of the control, and the vehicle driver is decelerated. A sense of discomfort at the time can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described. An outline of a motion control device according to an embodiment of the present invention is shown in FIG. 1, and an overall configuration of a vehicle including the motion control device is shown in FIG. First, in FIG. 1, there is provided deceleration control means M1 for performing deceleration control of the vehicle. The grip degree monitoring means M2 for monitoring the grip degree and the grip degree detected by the grip degree monitoring means M2 are compared with a control start threshold value, and based on the comparison result, the deceleration control means M1 performs deceleration control of the vehicle. Based on at least one of the operation state of the driver of the vehicle and the driving state of the vehicle, the degree of urgency estimation means M4 that estimates the degree of urgency that indicates the degree of possibility that the vehicle will become unstable. And threshold setting means M5 for setting a control start threshold according to the degree of urgency estimated by the degree of urgency estimation means M4.

  The deceleration control by the deceleration control means M1 means control for decelerating the vehicle regardless of the driver's braking operation. As the deceleration control means M1, for example, there is a brake fluid pressure control device BC. As indicated by the broken line, the throttle opening degree or fuel injection of the engine EG may be controlled, or the transmission control device GS may be controlled (shifted down) for deceleration.

  The degree of urgency estimation means M4 can be configured to estimate the degree of urgency based on the change rate of the grip degree detected by the grip degree monitoring means M2. Alternatively, as shown by the broken line in FIG. 1, if the steering operation angle detection means M6 for detecting the steering operation angle of the driver of the vehicle is provided, the urgency degree estimation means M4 may be the steering operation angle detection means M6. The degree of urgency can be estimated based on at least one of the detected steering operation angle and the operation angular velocity that is the rate of change thereof. Further, if the brake operation amount detection means M7 for detecting the brake operation amount of the driver of the vehicle is provided, the degree of urgency estimation means M4 may detect the brake operation amount detected by the brake operation amount detection means M7 and its change rate. The degree of urgency can be estimated based on at least one of the braking operation speeds.

  Further, as shown by a broken line in FIG. 1, the vehicle state detection means M8 for detecting at least one of the lateral acceleration, the yaw rate, the side slip angle, and the roll angle, which are indices representing the driving state of the vehicle, is provided. For example, the degree of urgency estimation means M4 can be configured to estimate the degree of urgency based on the rate of change of at least one of the indices representing the driving state of the vehicle detected by the vehicle state detection means M8.

  In particular, in the present embodiment, since the grip degree is used as an index representing the margin in the lateral direction of the tire with respect to the traveling road surface, the vehicle behavior trend can be estimated before the tire reaches the limit. That is, the grip degree is a parameter that expresses how much force is generated with respect to the maximum force that can be generated by the tire as a margin to the limit, and is calculated as described in Non-Patent Document 2 described above. Therefore, if the grip degree is used, the vehicle stabilization control can be appropriately performed from the normal region before reaching the friction limit region.

  Regarding the grip degree, in the above-mentioned Non-Patent Document 2, the grip degree is obtained by setting the reference self-aligning torque for the self-aligning torque with respect to the wheel slip angle, but the lateral force is used instead of the wheel slip angle. It is good as well. In this case, as in the case of the wheel slip angle, the inclination of the self-aligning torque with respect to the lateral force in the vicinity of zero lateral force is obtained, and the reference self-aligning torque with respect to the lateral force is set. The grip degree can be obtained based on the ratio between the reference self-aligning torque and the actual self-aligning torque. Furthermore, it is good also as calculating | requiring a grip degree in consideration of both the grip degree (epsilon) SA calculated | required in relation to a wheel slip angle, and the grip degree (epsilon) CF calculated | required in relation to a lateral force. In this case, for example, the grip degree ε may be obtained as ε = K1 · εSA + K2 · εCF using the weighting coefficients K1 and K2.

  FIG. 2 shows an overall configuration of a vehicle including one embodiment of the motion control apparatus described above. The steering system of this embodiment includes an electric power steering system (EPS). The electric power steering system is already on the market, and the steering torque Tstr acting on the steering shaft 2 by the operation of the steering wheel SW by the driver is detected by the steering torque sensor TS, and the EPS according to the value of the detected steering torque Tstr. The motor (electric motor) MT is controlled to steer the wheels FL and FR ahead of the vehicle via the reduction gear and the rack and pinion, thereby reducing the steering operation force of the driver.

  As shown in FIG. 2, the engine EG of the present embodiment is an internal combustion engine having a throttle control device TH and a fuel injection device FI. In the throttle control device TH, the throttle opening is controlled according to the operation of the accelerator pedal AP. The Further, the throttle control device TH is driven to control the throttle opening, and the fuel injection device FI is driven to control the fuel injection amount in accordance with the output of the electronic control unit ECU. The engine EG of the present embodiment is connected to the wheels RL and RR on the rear side of the vehicle via a speed change control device GS and a differential gear DF, so that a so-called rear wheel drive system is configured. It is not limited to.

  Next, in the braking system of the present embodiment, wheel cylinders Wfl, Wfr, Wrl, Wrr are mounted on the wheels FL, FR, RL, RR, respectively, and the brake fluid pressure control device BC is mounted on these wheel cylinders Wfl, etc. Is connected. The brake fluid pressure control device BC includes a plurality of solenoid valves and an automatic fluid pressure generating source (a fluid pressure pump), and has a fluid pressure circuit configuration capable of automatic pressurization. This is the same as a conventional general apparatus, and the present embodiment is not particularly characterized by hydraulic pressure control, and therefore is not shown. 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.

  Further, as shown in FIG. 2, wheel speed sensors WS1 to WS4 are disposed on the wheels FL, FR, RL, and RR, and these are connected to the electronic control unit ECU, and the rotational speed of each wheel, that is, the wheel speed. A pulse signal having a number of pulses proportional to is input to the electronic control unit ECU. Furthermore, a stop switch ST that is turned on when the brake pedal BP is depressed, a steering angle sensor SS that detects the steering angle θh of the wheels FL and FR in front of the vehicle, a longitudinal acceleration sensor XG that detects the longitudinal acceleration Gx of the vehicle, the vehicle A lateral acceleration sensor YG that detects the lateral acceleration Gy of the vehicle, a yaw rate sensor YS that detects the yaw rate γ of the vehicle, a steering torque sensor TS, and a rotation angle sensor RS that detects the rotation angle of the EPS motor MT are connected to the electronic control unit ECU. Has been.

  FIG. 3 shows the system configuration of the present invention. A steering control system (EPS), a brake control system (ABS, TRC, VSC) and a throttle control (SLT) system are connected via a communication bus. It is configured so that each other's system information can be shared. Among these, the steering control system (EPS) includes a steering torque sensor TS and a rotation angle sensor RS connected to a steering control unit ECU1 having a CPU, ROM and RAM for electric steering control, and a motor drive circuit AC1. An EPS motor MT is connected through the connector.

  The brake control system performs anti-skid control (ABS), traction control (TRC), and vehicle stability maintenance control (VSC). The brake control system includes a CPU, ROM and RAM for brake control. The unit ECU 2 includes a wheel speed sensor (typically represented by WS), a hydraulic pressure sensor (typically represented by PS), a stop switch ST, a yaw rate sensor YS, a longitudinal acceleration sensor XG, a lateral acceleration sensor YG, and a steering angle sensor SS. And a solenoid valve (typically represented by SL) is connected via a solenoid drive circuit AC2.

  In the throttle control (SLT) system, an actuator AC3 for throttle control is connected to a throttle control unit ECU3 having a CPU, ROM and RAM for throttle control. Each of these control units ECU1 to ECU3 is connected to a communication bus via a communication unit having a communication CPU, ROM and RAM. Thus, information necessary for each control system can be transmitted from another control system.

  In the vehicle motion control apparatus configured as described above, processing when the vehicle is decelerated and controlled will be described with reference to the flowchart shown in FIG. First, after initial processing is performed in step 101, various sensor signals are input as input processing in step 102, and wheel steering angle, vehicle speed, longitudinal acceleration, lateral acceleration, yaw rate, etc. are read, and a brake control unit Various information calculated by the ECU 2 is also read by the communication signal. Next, if necessary, parameters of anti-skid control (ABS) and traction control (TRC) are set in steps 103 and 104, respectively, but these controls are the same as those generally performed. Therefore, explanation here is omitted. Subsequently, in step 105, deceleration control corresponding to the degree of urgency, that is, urgency degree sensitive deceleration control is performed, which will be described later with reference to FIG. Then, the process proceeds to step 106, where parameters for vehicle stabilization control are set as necessary, output processing is performed in step 107, and the process returns to step 102.

  Next, the pressing degree sensitive deceleration control performed in step 105 will be described with reference to the flowchart shown in FIG. First, in step 201, the grip degree representing the tire margin in the lateral direction is calculated, but since it is described in the aforementioned Non-Patent Document 1, it is omitted here. Subsequently, the degree of urgency is estimated in step 202 as described later, and a control start threshold value is set in step 203 based on the estimation result. For example, when deceleration control is performed according to the grip degree, the grip degree serving as the start threshold is set as shown in the map of FIG. 6 according to the degree of urgency. Further, the target deceleration is calculated in step 204, which will be described later with reference to FIG. Then, the process proceeds to step 205, where the braking force (control amount) for each wheel is calculated so as to achieve the target deceleration, and deceleration control according to the degree of urgency is performed.

  The degree of urgency in the above step 202 can be estimated by various methods, and an example of these will be described with reference to FIGS. First, as shown in FIG. 7, the degree of urgency S1 is set according to the steering operation angular velocity, and the degree of urgency S2 is set according to the steering operation angle as shown in FIG. That is, the greater the steering operation angular velocity or the steering operation angle, the higher the tendency of the vehicle to become unstable, so the degree of urgency S1 or S2 is set to be larger. Further, as shown in FIG. 9, the degree of urgency S3 is set according to the vehicle body speed (vehicle speed), and the degree of urgency S4 is set according to the road surface friction coefficient as shown in FIG. That is, since the vehicle tends to become unstable as the vehicle speed increases, the pressing degree S3 is set to be large. Further, since the vehicle tends to become unstable as the road surface friction coefficient (μ) decreases, the degree of urgency S4 is set to be large. Then, the urgency S is obtained by weighting the urgency S1 to S4 set in this way as follows.

S = (A * S1 + B * S2 + C * S3 + D * S4) / (A + B + C + D)
Here, A to D are weighting coefficients.

  In the degree of urgency S, (A * S1) is a basic component, (B * S2 + C * S3 + D * S4) is an auxiliary component, and the latter auxiliary component may be deleted. It should be noted that yaw rate, lateral acceleration, and side slip angle are used instead of the steering operation angle when setting the degree of urgency S2, and the gradient, that is, the yaw rate change amount, when setting the degree of urgency S1, instead of the steering operation angular velocity. The lateral acceleration change amount and the side slip angular velocity may be used.

Further, regarding the estimation of the degree of urgency, the degree of urgency S5 can be estimated based on the change rate of the grip degree (grip degree change gradient) as shown in FIG. 11 instead of the steering operation angular velocity of FIG. In this case, for example, the degree of urgency S3 shown in FIG. 9 may be used together, and the degree of urgency S may be obtained by weighting with weighting factors E and F as follows.
S = (E * S5 + F * S3) / (E + F)

  Next, the target deceleration calculation process performed in step 204 will be described with reference to FIG. First, in step 301, it is determined whether or not the urgency level sensitive deceleration control is currently being executed. If it is determined that the urgency-sensitive deceleration control is not currently executed and the control state is not controlled, the process proceeds to step 302 to determine whether control can be started. That is, the grip degree at that time is compared with the control start threshold value, and if it is below the control start threshold value, it is determined that the deceleration control start condition is satisfied, and the process proceeds to step 303 to set the target deceleration. Is done.

  For example, based on the map shown in FIG. 13, the distance (ie, deviation) of the position (black point in FIG. 13) specified according to the current grip degree and the aforementioned urgency degree S with respect to the solid line representing the start threshold value. The target deceleration is set to be proportional. Alternatively, based on the map shown in FIG. 14, the position (black point in FIG. 14) specified according to the current grip degree and the degree of urgency S is proportional to the angle (that is, angle deviation) with respect to the solid line representing the start threshold value. The target deceleration may be set to do so. Thus, if the target deceleration is set to increase according to the deviation, the deceleration control amount is small immediately after the start of the control, and the driver feels uncomfortable during deceleration. In step 302, if it is determined that the grip degree at that time is equal to or greater than the control start threshold value, the process proceeds to step 304, where the target deceleration is initialized (set to zero).

  Furthermore, the target deceleration set as described above may be corrected according to the road surface friction coefficient or the vehicle body weight. In this case, it is desirable to set so that the tire does not lock even if the road surface friction coefficient decreases. For example, with respect to the target deceleration TG1 set according to the deviation (distance or angle) as shown in FIG. 15, the target deceleration TG2 set according to the road surface friction coefficient as shown in FIG. As shown in FIG. 17, the target deceleration TG3 set in accordance with the vehicle body weight is weighted and a new target deceleration TG is set as follows (* represents the weight calculation). TG = TG1 * TG2 * TG3

  In addition, it is good also as using the parameter | index which can be linked | related with this instead of said road surface friction coefficient, for example, using the parameter | correlation with a road surface friction coefficient from the magnitude | size of the self-aligning torque at the time of control start. It is good as well. Also, when in the hysteresis region between the control start threshold value and the control end threshold value, the value set at the start of control is held, or at the end of control, a value smaller than the value at the start of control It is set to be gradually reduced so that

  Returning to the flowchart of FIG. 12, when it is determined in step 301 that the urgency-sensitive deceleration control is currently being executed, the process proceeds to step 305 to determine whether or not the control is complete. That is, the grip degree at that time is compared with the control end threshold value. If the grip degree is higher than the control end threshold value, it is determined that the deceleration control end condition is satisfied, and the routine proceeds to step 306 to set the target deceleration. Initialized (set to zero). If the grip degree in step 305 is less than or equal to the control end threshold value, the process proceeds to step 303 and deceleration control is continued. As the end condition, for example, based on the map shown in FIG. 18, the end condition can be set to end when the current grip degree is restored to a predetermined level. Alternatively, based on the map shown in FIG. 19, it may be set to end when the current grip degree and the urgency degree S are in a predetermined relationship. Further, based on the map shown in FIG. It may be set to end when a predetermined amount is recovered with respect to the control start threshold value.

  The deceleration control described above may be a deceleration control based on a shift control such as a downshift in addition to a deceleration control based on a brake control, or a deceleration control based on an engine control such as throttle control or fuel cut. For example, details of the speed change control device are omitted, but the setting of the control start threshold value and the calculation of the target deceleration are the same as described above when performing deceleration control by speed change control. However, it is necessary to adjust the control start threshold according to the response of the actuator to be used, and it should be noted that the settable deceleration range is narrower than the deceleration control by the brake control. For example, when a continuously variable transmission such as CVT is used, the gear ratio is shifted to a target deceleration, and when a multi-speed transmission such as an automatic transmission (AT) is used. Then, the shift is shifted to a shift speed that is the closest to the target deceleration.

  Thus, in any aspect, the deceleration control in accordance with the driver's feeling is appropriately performed based on the grip degree that represents the margin in the lateral direction of the tire. In other words, the more likely the vehicle is to become unstable, the more urgent the vehicle driver is, the earlier the deceleration control starts, and the less likely the vehicle will become unstable. If it is determined that there is, the deceleration control starts late.

It is a block diagram which shows the outline | summary of one Embodiment of the vehicle motion control apparatus of this invention. 1 is a configuration diagram showing an overall configuration of an embodiment of a vehicle motion control device of the present invention. It is a block diagram showing a system configuration concerning one embodiment of a motion control device of the present invention. It is a flowchart which shows the process of the deceleration control in one Embodiment of this invention. It is a flowchart which shows the process of the urgency degree sensitive deceleration control in one Embodiment of this invention. It is a graph which shows the relationship between the grip degree used as the starting threshold value of deceleration control in one Embodiment of this invention, and the degree of urgency. It is a graph which shows the map which sets the urgency S1 according to steering operation angular velocity in one Embodiment of this invention. It is a graph which shows the map which sets the urgency S2 according to a steering operation angle in one Embodiment of this invention. It is a graph which shows the map which sets the pressing degree S3 according to the vehicle speed in one Embodiment of this invention. It is a graph which shows the map which sets the urgency degree S4 according to a road surface friction coefficient in one Embodiment of this invention. It is a graph which shows the map which sets the urgency degree S5 according to the grip degree change gradient in one Embodiment of this invention. It is a flowchart which shows the process of the target deceleration calculation in one Embodiment of this invention. It is a graph which shows an example of the map which sets target deceleration according to the present grip degree and urgency degree in one embodiment of the present invention. It is a graph which shows the other example of the map which sets a target deceleration according to the present grip degree and urgency degree in one Embodiment of this invention. It is a graph which shows the map which sets target deceleration TG1 according to deviation (distance or angle) in one embodiment of the present invention. It is a graph which shows the map which sets target deceleration TG2 according to a road surface friction coefficient in one Embodiment of this invention. It is a graph which shows the map which sets target deceleration TG3 according to vehicle body weight in one Embodiment of this invention. It is a graph which shows an example of the map which sets completion | finish conditions in one Embodiment of this invention. It is a graph which shows the other example of the map which sets completion | finish conditions in one Embodiment of this invention. It is a graph which shows the further another example of the map which sets completion | finish conditions in one Embodiment of this invention.

Explanation of symbols

SW Steering wheel SS Steering angle sensor MT EPS motor TS Steering torque sensor EG Engine GS Shift control device BC Brake fluid pressure control device FL, FR, RL, RR Wheel WS1 to WS4 Wheel speed sensor YS Yaw rate sensor XG Longitudinal acceleration sensor YG Lateral acceleration Sensor ECU Electronic control unit

Claims (6)

  In a vehicle motion control apparatus that performs vehicle stabilization control based on a grip degree that represents a lateral margin of a tire with respect to a traveling road surface, a deceleration control means that controls deceleration of the vehicle, and a grip degree monitoring means that monitors the grip degree Comparing the grip degree detected by the grip degree monitoring means with a control start threshold value, and based on the comparison result, start determination means for determining start of deceleration control of the vehicle by the deceleration control means, and Based on at least one of the driver's operation state and the driving state of the vehicle, the degree of urgency estimation means for estimating the degree of urgency representing the degree of possibility that the vehicle becomes unstable, and the urgency level estimated by the degree of urgency estimation means And a threshold value setting means for setting the control start threshold value according to the degree.   2. The vehicle motion control device according to claim 1, wherein the degree of urgency estimating means is configured to estimate the degree of urgency based on a change rate of the grip degree detected by the grip degree monitoring means.   Steering angle detection means for detecting a steering angle of the driver of the vehicle is provided, and the degree of urgency estimation means is at least one of the steering angle detected by the steering angle detection means and the operation angular velocity as the rate of change thereof. The vehicle motion control apparatus according to claim 1, wherein the degree of urgency is estimated based on one side.   Brake operation amount detection means for detecting a brake operation amount of the driver of the vehicle is provided, and the degree of urgency estimation means is at least one of a brake operation amount detected by the brake operation amount detection means and a brake operation speed as a rate of change thereof. The vehicle motion control apparatus according to claim 1, wherein the degree of urgency is estimated based on one of the two.   Vehicle state detection means for detecting at least one of a lateral acceleration, a yaw rate, a side slip angle, and a roll angle as an index representing the driving state of the vehicle; and the degree of urgency estimation means is detected by the vehicle state detection means 2. The vehicle motion control apparatus according to claim 1, wherein the degree of urgency is estimated based on at least one of the indexes representing the driving state of the vehicle or a change rate thereof. The deceleration control means sets at least one of a target deceleration and a deceleration control amount according to a deviation between the grip degree detected by the grip degree monitoring means and the control start threshold set by the threshold setting means. 6. The vehicle motion control device according to claim 1, wherein the vehicle motion control device is configured as described above.

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