JP2010188916A - Vehicle motion controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle motion controller properly controlling an actual yaw rate even if a self-steering state occurs. <P>SOLUTION: The vehicle motion controller includes a direct yaw control device controlling the actual yaw rate to be generated in a vehicle with a predetermined normative yaw rate as a target value, and sets the target value such that the actual yaw rate is suppressed instead of the normative yaw rate. The actual yaw rate generated by the self-steering state is uniformly suppressed and reduced, to properly control the actual yaw rate without giving discomfort to a driver. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle motion control apparatus having a direct yaw control device that controls an actual yaw rate generated in a vehicle.

  Conventionally, as a direct yaw control device, a vehicle motion equipped with a left / right driving force distribution device capable of controlling the ratio of the driving force distributed to the left and right driving wheels and a rear wheel toe angle control device capable of controlling the rear wheel toe angle. A control device has been proposed (see, for example, Patent Document 1).

JP 2008-239115 A

  The vehicle is provided with a steering device, and the driver can steer the steered wheels in a desired direction. However, a kickback or the like causes a self-steer state in which the steering angle changes against the driver's intention. There is a case. Since the change in rudder angle causes the vehicle to generate actual yaw (rate), the direct yaw control device controls the actual yaw rate based on the change in rudder angle, but the change in rudder angle in the self-steer state is In some cases, the direct yaw control device may exhibit unexpected behavior. In such a case, it is considered that the actual yaw rate cannot be appropriately controlled, that is, the driver may feel uncomfortable. According to the fail-safe concept, it is desirable to allow the self-steer state to occur and to control the actual yaw rate appropriately even if the self-steer state occurs.

  Accordingly, an object of the present invention is to provide a vehicle motion control device that can appropriately control an actual yaw rate even when a self-steer state occurs.

  The present invention includes a direct yaw control device that controls an actual yaw rate generated in a vehicle using a predetermined standard yaw rate as a target value. When self-steering occurs in a steering apparatus, the actual yaw rate is replaced with the standard yaw rate. It is a vehicle motion control device that sets the target value so as to suppress the above. Since the actual yaw rate generated due to the self-steer state is uniformly suppressed and reduced, it is possible to perform appropriate control on the actual yaw rate without causing the driver to feel uncomfortable.

  In the present invention, the direct yaw control device includes a left / right driving force distribution device capable of controlling a ratio of driving forces distributed to the left and right driving wheels, and a rear wheel toe angle control device capable of controlling a rear wheel toe angle. It is preferable to have at least one of the above, and the direct yaw control device can be easily mounted on the vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, even if a self-steer state generate | occur | produces, the vehicle motion control apparatus which can control an actual yaw rate appropriately can be provided.

It is a lineblock diagram of vehicles provided with a vehicle motion control device concerning an embodiment of the present invention. It is a block diagram of the control part which the vehicle motion control apparatus which concerns on embodiment of this invention has. It is a flowchart of the (vehicle motion) control method of a DYC device. It is a graph showing the state of the vehicle during the occurrence of the self-steering state, (a) shows the time change of the steering angle, (b) shows the time change of the fail signal and the EPS OFF signal, (c) shows the RTC yaw rate. (D) shows the time change of the vehicle yaw rate.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  In FIG. 1, the block diagram of the vehicle 2 provided with the vehicle motion control apparatus 1 which concerns on embodiment of this invention is shown. A pair of left and right front wheels 3 are arranged in the front part of the vehicle 2, and a pair of left and right rear wheels 4 are arranged in the rear part. The pair of left and right front wheels 3 and the pair of left and right rear wheels 4 are steered wheels.

  The pair of left and right front wheels 3 can be steered by an EPS (electric power steering device) 8. The EPS 8 transmits the steering torque generated when the driver steers the handle 19 to the front wheels 3 to steer the front wheels 3, and rotates the front wheels 3 according to the steering torque generated when the driver steers the handle 19. An auxiliary torque that assists the rudder is generated. Depending on the road surface condition, for example, if there is a step or the like on the road, kickback or the like may occur, and the front wheel 3 may be steered against the driver's intention. The EPS 8 is configured not to generate an auxiliary torque for such a turning contrary to the driver's intention, and to generate a “1” value as an EPS OFF signal and transmit it to the control unit 5. .

  Further, the pair of left and right front wheels 3 can be rotated by the driving force transmitted from the DYC device (left / right driving force distribution device) 7 to drive the vehicle 2. The DYC device (left / right driving force distribution device) 7 can change the distribution ratio between the driving force transmitted to the left front wheel 3 and the driving force transmitted to the right front wheel 3. By giving the difference to the actual yaw (rate) in the vehicle 2 can be generated. Further, the direction of the actual yaw rate to be generated with respect to the vehicle 2 can be freely changed by making the driving force of the left front wheel 3 larger or smaller than the driving force of the right front wheel 3. Accordingly, if the actual yaw rate has already occurred in the vehicle 2, the actual yaw rate that has already occurred is substantially suppressed by causing the DYC device (left / right driving force distribution device) 7 to generate the actual yaw rate in the reverse direction. Can be reduced.

  The DYC device (left / right driving force distribution device) 7 transmits a device operation status such as a distribution ratio to the DYC device control unit 6. The DYC device control unit 6 determines whether the DYC device (left / right driving force distribution device) 7 is based on the device operation status received from the DYC device (left / right driving force distribution device) 7 and the device control amount received from the control unit 5. The distribution ratio is controlled.

  The pair of left and right rear wheels 4 can be steered (toe angle control) by a DYC device (rear wheel toe angle control device) 10. By turning the left and right rear wheels 4 in the right direction or in the left direction, the vehicle 2 can generate an actual yaw (rate). And the direction with respect to the vehicle 2 of the real yaw rate to generate | occur | produce can be freely changed by making it steer rightward or to steer leftward. Thus, if the actual yaw rate has already occurred in the vehicle 2, the actual yaw rate that has already occurred can be substantially reduced by generating the actual yaw rate in the reverse direction by the DYC device (rear wheel toe angle control device) 10. It can be suppressed and reduced. Further, even if the pair of left and right rear wheels 4 are steered to the toe-in, the straight traveling performance of the vehicle 2 is increased, and the actual yaw rate that has already occurred can be suppressed and reduced.

  The DYC device (rear wheel toe angle control device) 10 transmits the device operating status such as the turning angle of the pair of left and right rear wheels 4 to the DYC device control unit 9. The DYC device control unit 9 is configured based on the device operation status received from the DYC device (rear wheel toe angle control device) 10 and the device control amount received from the control unit 5. The turning angle of the left and right rear wheels 4 is controlled.

The vehicle motion control device 1 includes the control unit 5, the DYC device control unit 6, the DYC device (left / right driving force distribution device) 7, the EPS 8, the DYC device control unit 9, and the DYC device ( Rear wheel toe angle control device) 10. Details of the control unit 5 will be described later.
The vehicle speed (signal) measured by the vehicle speed sensor 11, the actual yaw rate (signal) measured by the yaw rate sensor 12, the lateral G (signal) measured by the lateral G sensor 13, and the steering angle sensor 14 A steering angle (signal), a steering (handle) torque (signal) measured by the handle torque sensor 15, and an ON signal and an OFF signal output from an IG (ignition switch) 16 are transmitted. The camera 17 </ b> R is disposed in front of the right side of the vehicle 2, captures the outside world from the front of the vehicle 2 to the right side, and transmits the generated image data to the control unit 5. Similarly, the camera 17 </ b> L is disposed in front of the left side of the vehicle 2, captures the outside world from the front of the vehicle 2 to the left side, and transmits the generated image data to the control unit 5.

  In FIG. 2, the block diagram of the control part 5 which the vehicle motion control apparatus 1 has is shown. The accumulating unit 21 accumulates the reciprocal (1 / V) of the lateral G (Gy) and the vehicle speed (V). The accumulating unit 22 calculates the actual yaw rate (γ) and the transfer function model Gγ from the actual yaw rate to the lateral G in the normal operation region in which the fluctuation of the friction coefficient μ of the road surface and the saturation of the friction coefficient μ of the tire do not occur. Accumulate. The subtracting unit 23 calculates the control input Uerr (= Gy / V−Gγ · γ) by subtracting the integrated value (Gγ · γ) in the integrating unit 22 from the integrated value (Gy / V) in the integrating unit 21. To do. Since the control input Uerr constantly converges to zero (0 = Gy / V−Gγ · γ) in the normal operation region, the transfer function model Gγ is determined in advance from this. Can do. When a change in the friction coefficient μ of the road surface occurs, the control input Uerr does not converge to zero, and oversteer or understeer (US / OS) occurs in the vehicle 2. The control input Uerr represents the angular velocity (dβ / dt) of the vehicle slip angle (β), and distinguishes between oversteer and understeer (US / OS) according to its positive / negative, and oversteer and understeer (US / OS) depending on its magnitude. The size can be estimated. Oversteer and understeer (US / OS) can be suppressed by generating actual yaw (rate) in the DYC devices 7 and 10. For this reason, the control input Uerr representing oversteer and understeer (US / OS) is multiplied by the gain gs by the accumulating unit 24 and then the device control amount via the summing unit 26, so that the DYC device control unit 6 and 9 are transmitted.

  The reference vehicle modeling unit 27 calculates a reference yaw rate based on the measured vehicle speed and rudder angle using a two-wheel model or the like. When the value is “0”, the changeover switch 28 is connected to the reference yaw rate side and outputs the reference yaw rate as a target yaw rate (target value). The subtraction unit 32 calculates the yaw rate deviation Δγ by subtracting the measured actual yaw rate from the target yaw rate (target value). If the yaw rate deviation Δγ becomes zero, the actual yaw rate matches the standard yaw rate that is the target yaw rate (target value), and the vehicle 2 can travel comfortably. According to the DYC devices 7 and 10, the actual yaw (rate) can be increased or decreased to make the yaw rate deviation Δγ zero. Therefore, the yaw rate deviation Δγ to be controlled to zero is multiplied by the gain gΔ by the accumulating unit 25 and then transmitted to the DYC device control units 6 and 9 as the device control amount via the summation unit 26. ing.

  The yaw rate suppression unit 29 sets a yaw rate having an absolute value smaller than the actual yaw rate as the zero convergence yaw rate based on the measured actual yaw rate. When the value is “1”, the changeover switch 28 is connected to the zero convergence yaw rate side and outputs the zero convergence yaw rate as a target yaw rate (target value). The subtraction unit 32 calculates the yaw rate deviation Δγ by subtracting the measured actual yaw rate from the target yaw rate (target value). When the yaw rate deviation Δγ becomes zero, the actual yaw rate matches the zero convergence yaw rate that is the target yaw rate (target value), and the actual yaw rate approaches zero. According to the DYC devices 7 and 10, an actual yaw rate close to zero can be realized. The yaw rate suppression unit 29 again sets a yaw rate having an absolute value smaller than the actual yaw rate as the zero convergence yaw rate. An actual yaw rate that is closer to zero can be realized. Finally, the actual yaw rate can be converged to zero and suppressed.

  The self-steer determination unit 30 determines whether or not a self-steer state has occurred in the EPS 8, which is a steering device, based on the measured steering angle and steering wheel torque. The driver holds the handle 19 and applies handle torque in the direction of the intention to steer. When not in the self-steering state, the rudder angle also cuts in the same direction as the direction in which the handle torque is applied, and the rudder angular speed directions coincide. However, in the case of the self-steering state, the rudder angle is cut in a direction opposite to the direction in which the handle torque is applied against the intention, and the rudder angular velocity direction is also in the opposite direction. The self-steer determination unit 30 determines whether or not a self-steer state has occurred in the EPS 8 based on the difference in direction such as the steering angular velocity. When the self-steer determination unit 30 determines that a self-steer state has occurred, a “1” value is generated as a fail signal and transmitted to the OR operation unit 31. The OR operation unit 31 performs an OR operation on the fail signal and the EPS OFF signal. The OR operation unit 31 outputs a “1” value (corresponding to a self-steer state) when at least one of the fail signal and the EPS OFF signal is a “1” value. When “0” is also the value “0” (not corresponding to the self-steer state) is output. The changeover switch 28 is connected to the reference yaw rate side when a “0” value (not corresponding to the self-steer state) is input, and when a “1” value (corresponding to the self-steer state) is input, the zero convergence yaw rate is set. Connect to the side.

  The device control amount changing unit 18 changes the device control amount output from the summation unit 26. The device control amount change unit 18 includes a camera selection unit 18a and an obstacle detection determination unit 18b. Based on the steering angle and the actual yaw rate, the camera selection unit 18a determines whether the vehicle 2 is going to travel in the right direction or the left direction, and transmits a selection signal to the determined cameras 17L and 17R. Then, one of the cameras 17L and 17R is selected. The obstacle detection / determination unit 18b receives image data obtained by photographing the outside world as the right obstacle signal or the left obstacle signal from the selected cameras 17L and 17R, and uses a technique such as image recognition to run parallel vehicles, etc. It is determined whether or not an obstacle such as is detected. If it is determined that an obstacle is detected, the device control amount is uniformly changed so that the rear wheel is toe-in so that the vehicle 2 does not approach the obstacle.

  FIG. 3 shows a flowchart of a (vehicle motion) control method of the DYC devices 7 and 10. The (vehicle motion) control method starts when the IG (ignition switch) 16 is turned on.

  In step S1, the control unit 5 determines whether or not the IG 16 is turned off. In the case of determination that IG16 is turned off (step S1, Yes), the (vehicle motion) control method is stopped, and in the case of determination that IG16 is not turned off (step S1, No), Proceed to step S2.

  In step S2, the self-steer determination unit 30 determines whether or not a self-steer state has occurred. When it is determined that the self-steer state has occurred (step S2, Yes), the process proceeds to step S4. When it is determined that the self-steer state has not occurred (step S2, No), the process proceeds to step S3. move on. As shown in FIG. 4A, when the self-steering state occurs in the EPS 8, the measured steering angle increases regardless of the driver's intention.

  In step S3, the reference yaw rate calculated by the reference vehicle modeling unit 27 is used as a target yaw rate (target value), a yaw rate deviation Δγ is calculated, and the process proceeds to step S7.

  In step S4, the self-steer determination unit 30 receives the determination that the self-steer state has occurred, and turns on the fail signal to set the value to “1” as shown in FIG. 4B. The self-steering state can also be detected when the EPS OFF signal is turned on and becomes “1” value, and can be used in place of the fail signal.

  In step S5, the changeover switch 28 switches the connection from the reference yaw rate side to the zero convergence yaw rate side when at least one of the fail signal and the EPS OFF signal is on and has a "1" value.

  In step S6, the yaw rate deviation Δγ is calculated using the zero convergence yaw rate set by the yaw rate suppression unit 29 as the target yaw rate (target value).

  In step S7, the control unit 5 calculates a device control amount. For this purpose, in step S7a, the integrating unit 25 calculates the first term (Δγ · gΔ) based on the yaw rate deviation Δγ as a yaw rate deviation correction amount. In step S7b, the integrating unit 24 calculates the second term (Uerr · gs) based on the control input Uerr indicating the angular velocity (dβ / dt) of the vehicle slip angle (β) as the US / OS control correction amount. In step S <b> 7 c, the summation unit 26 calculates the sum of the first term (Δγ · gΔ) and the second term (Uerr · gs) as the device control amount. In step S7, the device control amount is calculated regardless of whether the self-steering state has occurred. However, the calculated device control amount differs depending on whether the self-steer state has occurred or not, since the yaw rate deviation Δγ to be used is different. Also, the handling of the device control amount after the calculation differs depending on whether the self-steer state has occurred or not. If the self-steer state has not occurred, the DYC device control units 6 and 9 and further the DYC devices 7 and 10 are controlled based on the calculated device control amount, and the process returns to step S1 to repeatedly control the device. Calculate the amount. On the other hand, if the self-steering state has occurred, the process proceeds to step S8.

  In step S8, the camera selection unit 18a of the device control amount changing unit 18 transmits a selection signal to the cameras 17L and 17R in the direction of the actual yaw rate being measured, and selects one of the cameras 17L and 17R. .

  In step S9, the obstacle detection determining unit 18b of the device control amount changing unit 18 receives image data obtained by photographing the outside world from the selected cameras 17L and 17R, and detects an obstacle such as a vehicle running in parallel. It is determined whether it has been done. If it is determined that an obstacle has been detected (step S9, Yes), the process proceeds to step S11, and the device control amount is uniformly set to make the rear wheels toe-in so that the vehicle 2 does not approach the obstacle. change. If it is determined that no obstacle has been detected (No in step S9), the process proceeds to step S10, and the device control amount is not changed. For example, based on the device control amount, the DYC device control unit 9 A DYC device (rear wheel toe angle control device) 10 controls the steering angle of the rear wheel 4 in phase with the steering angle of the front wheel 3. As a result of this control, as shown in FIG. 4C, the RTC yaw rate for the rear wheel toe angle control that has been increased with the increase in the steering angle (see FIG. 4A) has started to decrease. I understand that. The vehicle yaw rate of the vehicle 2 as a whole also increases as the rudder angle (see FIG. 4A) increases as shown in FIG. 4D. However, the vehicle yaw rate decreases as the fail signal is generated. It turns out that it has turned to. Since the cameras 17L and 17R are used to detect an obstacle, the cameras 17L and 17R are not limited to the cameras 17L and 17R as long as an obstacle can be detected. For example, an ultrasonic sensor or the like can be used.

  In step S12, the control unit 5 determines whether or not the measured actual yaw rate has converged to zero. Specifically, it is determined whether or not the absolute value of the actual yaw rate has reached an area that is equal to or smaller than a predetermined threshold value. If it is determined that the actual yaw rate has converged to zero (step S12, Yes), the process returns to step S1 to prepare for the occurrence of the next self-steer state. If it is determined that the actual yaw rate has not converged to zero (step S12, No), the process returns to step S6, and the yaw rate deviation Δγ is calculated again using the zero convergence yaw rate closer to zero. As a result, the vehicle yaw rate (actual yaw rate) can be converged to zero and suppressed as shown in FIG. Then, as shown in FIG. 4C, the RTC yaw rate continues to decrease until the vehicle yaw rate (actual yaw rate) converges to zero, thereby allowing the vehicle yaw rate (actual yaw rate) to converge to zero. ing.

DESCRIPTION OF SYMBOLS 1 Vehicle motion control apparatus 2 Vehicle 3 Front wheel (drive wheel)
4 Rear wheel 5 Control unit 6 DYC device control unit 7 DYC device (left and right driving force distribution device)
8 EPS (electric power steering device)
9 DYC device control unit 10 DYC device (rear wheel toe angle control device)
11 vehicle speed sensor 12 yaw rate sensor 13 lateral G sensor 14 rudder angle sensor 15 handle torque sensor 16 IG (ignition switch)
17L, 17R Camera 18 Device control amount change unit 18a Camera selection unit 18b Obstacle detection determination unit 19 Handle 21, 22, 24, 25 Accumulation unit 23 Subtraction unit 26 Summation unit 27 Reference vehicle modeling unit (two-wheel model etc.)
28 selector switch 29 yaw rate suppression unit 30 self-steer determination unit 31 OR operation unit 32 subtraction unit

Claims (2)

Having a direct yaw control device that controls the actual yaw rate generated in the vehicle with a predetermined standard yaw rate as a target value,
The vehicle motion control device according to claim 1, wherein when the self-steer occurs in the steering device, the target value is set to suppress the actual yaw rate instead of the reference yaw rate. The direct yaw control device is
A left and right driving force distribution device capable of controlling the ratio of the driving force distributed to the left and right driving wheels;
The vehicle motion control device according to claim 1, further comprising at least one of a rear wheel toe angle control device capable of controlling a toe angle of the rear wheel.

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