Control device for vehicle

Abstract

To enhance vehicle controllability by quantifying a spin behavior without using integration.SOLUTION: A control device 10 for a vehicle 1 comprises: vehicle speed detection means 21 that detects a vehicle speed V of the vehicle 1; yaw rate detection means 22 that detects a yaw rate r of the vehicle 1; lateral acceleration detection means 23 that detects the lateral acceleration Ay of the vehicle 1; a calculation unit 11 that calculates a first input value C1 representing a deviation between the lateral acceleration Ay and the product of the vehicle speed V and the yaw rate r, and a second input value C2 representing a time change amount of the deviation; an estimation means 12 that estimates a spin degree ks as an index representing the spin behavior of the vehicle 1 on the basis of the first input value C1 and the second input value C2; and a control unit 13 that controls an actuator or a notification device 9 of the vehicle 1 on the basis of the spin degree ks.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device that estimates an index representing the spin behavior of a vehicle and controls the vehicle.

Background Art

[0002] Conventionally, as one of vehicle motion controls, suppression of the spin behavior of a vehicle has been carried out. The spin behavior is a behavior in which, when the vehicle is turning, due to some cause, the grip force of the rear wheels decreases and the rear wheels slide laterally, causing the vehicle body to turn significantly inward. Techniques for estimating the occurrence of such spin behavior and techniques for suppressing spin behavior are known. For example, Patent Document 1 discloses a behavior control device that suppresses the spin of a vehicle based on a control amount calculated from a vehicle body slip angle, a differential value of the vehicle body slip angle, and a second-order differential value of the vehicle body slip angle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the device of Patent Document 1 described above, the vehicle speed, lateral acceleration, and yaw rate are detected by sensors, the differential value of the vehicle body slip angle is calculated, the vehicle body slip angle is calculated by integrating this differential value, and the second-order differential value of the vehicle body slip angle is calculated by further differentiating this differential value. However, since the integral value generally has a large integration error, it is preferable to be able to carry out the determination regarding the presence or absence and degree of spin behavior and the suppression control of spin behavior without using integration.

[0005] The vehicle control device of this case was devised in view of such problems, and one of its purposes is to quantify the spin behavior without using integration and improve the controllability of the vehicle. Note that, not limited to this purpose, another object of this case is to achieve effects that cannot be obtained by the prior art, which are the effects derived from each configuration shown in the embodiments for implementing the invention described later.

Means for Solving the Problems

[0006] The disclosed vehicle control device can be realized as the aspects or application examples disclosed below and solves at least part of the above problems. The disclosed vehicle control device is applied to a vehicle provided with a vehicle body speed detection means for detecting the vehicle body speed of the vehicle, a yaw rate detection means for detecting the yaw rate of the vehicle, and a lateral acceleration detection means for detecting the lateral acceleration of the vehicle. The control device includes a calculation unit that calculates a first input value representing the deviation between the lateral acceleration and the product of the vehicle body speed and the yaw rate, and a second input value representing the time change amount of the deviation, an estimation unit that estimates the degree of spin as an index representing the spin behavior of the vehicle based on the first input value and the second input value, and a control unit that controls the actuator or the notification device of the vehicle based on the degree of spin.

Effects of the Invention

[0007] According to the disclosed vehicle control device, since the degree of spin as an index representing the spin behavior is estimated without using integration, the spin behavior can be quantified, and based on this, the actuator and the notification device of the vehicle can be controlled, so that the controllability of the vehicle can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0009] A vehicle control device according to an embodiment will be described with reference to the drawings. The embodiments described below are merely examples, and are not intended to exclude the application of various modifications and techniques not specified in the following embodiments. The configurations of the respective embodiments can be modified in various ways without departing from the spirit of the embodiments. In addition, the embodiments can be selected or combined as necessary. In the following description, the forward movement direction of the vehicle is defined as the forward direction (front of the vehicle), and the left and right are defined based on the forward direction.

[0010] [1. Equipment configuration] The control device 10 of this embodiment is applied to a vehicle 1 illustrated in Fig. 1 and has a function of quantifying at least the spin behavior of the vehicle 1 and controlling it based on the quantified value. The control device 10 is one of the electronic control devices (ECU, Electronic Control Unit) mounted on the vehicle 1. The control device 10 is equipped with, for example, a processor (microprocessor) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a non-volatile memory, and the like.

[0011] The processor is an arithmetic processing unit that incorporates a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (register group), etc. Also, ROM, RAM, and non-volatile memory are memory devices in which programs and working data are stored. The content of estimation and control implemented by the control device 10 is recorded and stored in the memory as firmware or an application program. When the program is executed, the content of the program is expanded within the memory space and executed by the processor.

[0012] The vehicle 1 is, for example, an engine vehicle, an electric vehicle (EV; Electric Vehicle, HEV; Hybrid Electric Vehicle, PHEV; Plug-in Hybrid Electric Vehicle), or a fuel cell vehicle (FCV; Fuel Cell Vehicle) equipped with a drive source 3 such as an engine or an electric motor. Brake devices 4 are provided on the left and right front wheels 2FL, 2FR and the left and right rear wheels 2RL, 2RR of the vehicle 1, and each of the four wheels is independently brake-controlled. Also, the vehicle 1 is provided with a power steering device 5 that assists the driver's steering operation, an AFS6 (Active Front Steering) that can actively control the steering angle (front wheel steering angle) of the front wheels 2F (2FL, 2FR), and an ARS7 (Active Rear Steering) that can actively control the steering angle (rear wheel steering angle) of the rear wheels 2R (2RL, 2RR). Furthermore, the vehicle 1 of the present embodiment is provided with an active suspension 8 and a notification device 9 that announces to the driver by display or sound.

[0013] These devices 3 to 9 are individually controlled by an in-vehicle control device (not shown). For example, a control device for controlling the drive source 3 (engine ECU or motor ECU), a brake ECU for controlling the brake device 4, an ECU for controlling the power steering device 5, an ECU for controlling the AFS 6 and ARS 7, an ECU for controlling the active suspension 8, and an ECU for controlling the notification device 9 are mounted on the vehicle 1. In the present embodiment, when the control device 10 controls the devices 3 to 9, commands are sent to these various ECUs, and the various ECUs control the corresponding devices 3 to 7. Among the devices 3 to 9, the devices 3 to 8 that play a role of converting energy into mechanical displacement or stress may be called "actuators". Note that a common ECU may be provided with a function of controlling a plurality of devices 3 to 9.

[0014] The vehicle 1 is provided with sensors for acquiring various information of the vehicle 1. In the example shown in FIG. 1, a vehicle speed sensor 21, a yaw rate sensor 22, and a lateral acceleration sensor 23 are provided, and each of the sensors 21 to 23 is connected to the control device 10. The vehicle speed sensor 21 (vehicle body speed detection means) is a sensor that detects the vehicle body speed V of the vehicle 1, and the yaw rate sensor 22 (yaw rate detection means) is a sensor that detects the rotational angular velocity around the vertical axis passing through the center of gravity G of the vehicle 1 as the yaw rate r. In the present embodiment, as shown by the thick arrow in FIG. 1, the vehicle body speed V has a positive direction from the center of gravity G forward, and the yaw rate r has a positive direction counterclockwise around the center of gravity G when the vehicle 1 is viewed from above.

[0015] The lateral acceleration sensor 23 (lateral acceleration detection means) is a sensor that detects the lateral acceleration A y at the center of gravity G of the vehicle 1. In the present embodiment, as shown by the thick arrow in FIG. 1, the lateral acceleration A y has a positive direction from the center of gravity G to the left. The information detected by each of the sensors 21 to 23 is sent to the control device 10. Note that the means for detecting the vehicle body speed V is not limited to the vehicle speed sensor 21, and for example, a wheel speed sensor that detects the angular velocity of each wheel 2 may be provided, and the vehicle body speed V may be calculated from the detection value of the wheel speed sensor.

[0016] Similarly, the means for detecting the yaw rate r and the lateral acceleration A y are not limited to the yaw rate sensor 22 and the lateral acceleration sensor 23. For example, the lateral acceleration A y can be estimated based on the steering angle and the vehicle body speed V, or the estimated value and the value detected by the lateral acceleration sensor 23 can be corrected based on another sensor value to detect the lateral acceleration A y . Similarly, the yaw rate r may be detected by correcting the value detected by the yaw rate sensor 22 based on another sensor value. In such a case, the estimation unit and the correction unit (functional elements of the control device) can serve as the respective detection means. In addition to these sensors 21 to 23, general-purpose sensors such as an accelerator opening sensor, a brake sensor, and a steering angle sensor are provided in the vehicle 1.

[0017] [2. Control Overview] The control device 10 of the present embodiment uses the information detected by the various sensors 21 to 23 to estimate the "spin degree k s ", which is an index representing the spin behavior (the magnitude of the center of gravity slip angle β) of the vehicle 1, and controls the actuator or the notification device 9 accordingly. The spin degree k s of the present embodiment is set as a one-dimensional quantity with a minimum value of 0 and a maximum value of 1.

[0018] The spin degree k s of the present embodiment is 0 in a non-spinning state (i.e., a normal driving state), 1 in a completely spinning state (when the center of gravity slip angle β is equal to or greater than a predetermined upper limit value), and is a numerical value between 0 and 1. The spin degree k s is always estimated based on two input values C 1 , C 2 described later during the running of the vehicle 1.

[0019] Here, consider the spin behavior of the vehicle 1 using the model shown in FIG. 2. FIG. 2 models the vehicle 1 as a single rigid body and simplifies the degrees of freedom of motion to linearize it into a mathematical model of the vehicle 1 (linear two-wheel model). In FIG. 2, the vehicle 1 is regarded as a rigid body equipped with a front wheel 2F and a rear wheel 2R one by one, and only the planar motion in the lateral direction and yaw direction when the vehicle speed is constant is considered. Also, it is assumed that the cornering force generated by the wheel 2 is proportional to the sideslip angle.

[0020] Regardless of the presence or absence of the spin behavior of the vehicle 1, in the vehicle 1, as shown in Equation 1 below, the value obtained by multiplying the vehicle body speed V by the differential value of the center of gravity slip angle β (also called the vehicle body slip angle) (left side) and the lateral acceleration A y minus the product of the vehicle body speed V and the yaw rate r (right side) are known to be approximately equal.

[0021]

Equation

[0022] However, when lateral slip of the rear wheel 2R occurs, the center of gravity slip angle β changes significantly, and the magnitude (absolute value) of the center of gravity slip angle β increases significantly. This is the behavior called "spin", and the change in the center of gravity slip angle β is accompanied by a change in the left side of Equation 1. At this time, it can be seen that the lateral acceleration A y deviates from the product of the vehicle body speed V and the yaw rate r, Vr. In this state, as shown in FIG. 3, the time series waveform of the lateral acceleration A y (solid line in the figure) and the time series waveform of the product of the vehicle body speed V and the yaw rate r, Vr (dashed line in the figure) diverge. The divergence of these two time series waveforms (that is, the deviation between A y and Vr) is due to the fact that the rear wheel 2R is prone to lateral slip, that is, the rear wheel cornering power K r is small.

[0023] Regarding the above deviation, organize it using the model in FIG. 2. In the model of FIG. 2, the lateral acceleration A yWhen obtaining the transfer function \(G(s)\) of the product \(Vr\) of the vehicle body speed \(V\) and the yaw rate \(r\) with the input as such, as shown in Equation 2 below, it becomes an expression with a first-order numerator and a second-order denominator with a steady-state gain of 1. Here, \(a\) in Equation 2 1 , \(b\) 1 , \(b\) 2 are coefficients, and \(s\) is the Laplace operator.

[0024]

Equation

[0025] The process of deriving the third equation from the second equation of Equation 2 above will be explained. The equation of motion in the two-wheel model of Figure 2 is expressed by Equation 3 below. Here, \(m\) is the vehicle mass, \(I\) is the yaw inertia moment, \(K\) f is the front wheel cornering power, \(\beta\) f is the front wheel slip angle (the lateral slip angle of the front wheels 2F), \(\beta\) r is the rear wheel slip angle (the lateral slip angle of the rear wheels 2R), \(L\) f is the longitudinal distance between the front axle and the center of gravity \(G\), \(L\) r is the longitudinal distance between the rear axle and the center of gravity \(G\).

[0026]

Equation

[0027] Here, the slip angles \(\beta\) f , \(\beta\) r of the front wheels 2F and the rear wheels 2R are expressed by Equation 4 below. Here, \(\delta\) is the steering angle of the vehicle 1.

[0028]

Equation

[0029] In Equation 4 above, assuming that the vehicle body speed \(V\) is constant, Equation 3 above becomes linear with respect to the center of gravity slip angle \(\beta\) and the yaw rate \(r\). Under this assumption, when calculating the transfer function \(G(s)\) of Equation 2 above, it becomes Equation 5 below, and each coefficient \(a\) in the third equation of Equation 2 (the fourth equation of Equation 5 below)1 , b 1 , b 2 The content becomes clear. Here, L is the wheelbase (distance between the front and rear axles).

[0030] [Number]

[0031] As is clear from the above formula 5, the coefficients a 1 and b 2 include the rear wheel cornering power K r . Also, since m, L 1 and b 2 contained in these coefficients a f , I, L are vehicle specification values determined in advance, only the rear wheel cornering power K r is a parameter that can vary during driving. That is, when the rear wheel cornering power K r changes, the transfer function G(s) changes, and thereby the lateral acceleration A y and the product Vr are separated. That is, the change in the transfer function G(s) during driving means the increase or decrease of the rear wheel cornering power K r indicating the lateral slip tendency of the rear wheels 2R. Therefore, if the change in the transfer function G(s) is known, even without obtaining the center of gravity slip angle β, the lateral slip itself of the rear wheels 2R, which is the cause of the spin behavior, can be evaluated, and the occurrence of the spin behavior can be determined.

[0032] In this control device 10, the change in the transfer function G(s) is evaluated from the deviation (separation amount) of the time series waveform. The "deviation" here may be the difference, ratio, or a combination of the difference and ratio between the time series waveform of the lateral acceleration A y shown in FIG. 3 (solid line in the figure) and the time series waveform of the product Vr of the vehicle body speed V and the yaw rate r (dashed line in the figure). At least, it is important how much the lateral acceleration A y is separated from the product Vr of the vehicle body speed V and the yaw rate r at the current time. In this embodiment, the value obtained by subtracting the product Vr of the vehicle body speed V and the yaw rate r from the lateral acceleration A y (Ay The value obtained by correcting (specifically, removing) the lateral acceleration A by (-Vr) is the first input value C y and is used as the first input value C 1 .

[0033] As can be seen from the above equation 5, the deviation of the time-series waveform depends not only on the change in the rear-wheel cornering power K r but also on the amplitude of the lateral acceleration A y which is the input signal, and varies proportionally. In this control device 10, in order to eliminate the influence of the amplitude of the input value (input amplitude) of the transfer function G(s) from the deviation of the time-series waveform (i.e., the deviation between A y and Vr), the value (A y -Vr) is corrected (removed) by the lateral acceleration A y and the resulting value is used as the first input value C 1 . By doing so, the change in the transfer function G(s), that is, the change in the rear-wheel cornering power K r is simply evaluated from the time-series waveform.

[0034] In addition, in this control device 10, based on the time change amount of the deviation (the deviation amount of the time-series waveform) between the lateral acceleration A y and the product Vr of the vehicle body speed V and the yaw rate r, it is evaluated whether the current deviation is increasing or decreasing. In this embodiment, the first-order differential value of the first input value C 1 (the time change rate of the first input value C 1 ) is used as the second input value C 2 , and two input values C 1 , C 2 are used. Specifically, by evaluating the first input value C 1 and its time change rate, which is the second input value C 2 , the change in the transfer function, that is, the change in the rear-wheel cornering power K r is simply and accurately evaluated from the time-series waveform.

[0035] In the control device 10, based on the two input values C 1 , C 2 , the spin degree k s is estimated. In this estimation, as shown in FIG. 4, the control device 10 of this embodiment uses the first input value C 1Find the first input value C 1 Differentiate it to obtain the second input value C 2 Find each input value C 1 , C 2 From each, obtain each evaluation value E 1 , E 2 Then, using these two evaluation values E 1 , E 2 Estimate the spin degree k s By evaluating the change in responsiveness (transfer function), the change in the rear-wheel cornering power K r , that is, the spin behavior (the degree of lateral slip of the rear wheels 2R) can be evaluated, and control using the quantified spin behavior index (spin degree k s ) becomes possible.

[0036] Each evaluation value E 1 , E 2 is an index for evaluating the deviation between the lateral acceleration A 1 and the product Vr of the vehicle body speed V and the yaw rate r, respectively, from the first input value C 2 and the second input value C y . In this embodiment, it is set as a one-dimensional quantity with a minimum value of 0 and a maximum value of 1. The first evaluation value E 1 becomes 0 when the first input value C 1 is 0, and approaches 1 as the absolute value of the first input value C 1 increases, and becomes 1 when it is greater than or equal to a predetermined value. The second evaluation value E 2 is the same. It becomes 0 when the second input value C 2 is 0, and approaches 1 as the absolute value of the second input value C 2 increases, and becomes 1 when it is greater than or equal to a predetermined value. The relationship between the first input value C 1 and the first evaluation value E 1 , and the relationship between the second input value C 2 and the second evaluation value E 2 are stored in advance in the memory or storage device of the control device 10 in the form of, for example, a map, a table, a mathematical formula, etc.

[0037] The spin degree k s is based on two evaluation values E 1 , E 2It is calculated (estimated) based on this. Here, as shown in FIG. 4, the sum of two evaluation values E 1 , E 2 is calculated as the value obtained by taking the minimum of the sum and 1 (the value clipped by 1). This is because the maximum value of the spin degree k s in this embodiment is set to 1. The actuator and the notification device 9 are controlled according to the spin degree k s calculated (estimated) in this way.

[0038] [3. Control Configuration] The control device 10 includes a calculation unit 11, an estimation unit 12, and a control unit 13 (a first control unit 13A and a second control unit 13B) as functional elements for estimating the spin degree k s and performing each control. These elements are shown by classifying the functions of the control device 10 for convenience. These elements can be described as independent programs respectively, and can also be described as a composite program in which a plurality of elements are combined. The programs corresponding to the respective elements are stored in the memory or storage device of the control device 10 and executed by the processor.

[0039] The calculation unit 11 calculates the above two input values C 1 , C 2 . The first input value C 1 in this embodiment is, as shown in the following formula 6, the value obtained by dividing the value obtained by subtracting the product (=Vr) of the vehicle body speed V detected by the vehicle speed sensor 21 and the yaw rate r detected by the yaw rate sensor 22 from the lateral acceleration A y detected by the lateral acceleration sensor 23 by the lateral acceleration A y . As another example of the first input value C 1 , for example, the deviation or ratio between the lateral acceleration A y and the product Vr of the vehicle body speed V and the yaw rate r, and the value obtained by multiplying the lateral acceleration A y by a correction coefficient can be mentioned.

[0040]

Equation

[0041] Also, the second input value C of the present embodiment 2 is the first-order differential value of the first input value C as shown in the following Equation 7. Note that the second input value C 1 is a value that quantifies the rate of change (degree of increase or decrease) of the deviation, and thus may be given by, for example, the following Equation 8. 2

[0042]

Equation

[0043] The estimation unit 12 estimates the spin degree k 1 , C 2 based on the two input values C s . The estimation unit 12 of the present embodiment obtains the first evaluation value E 1 from the first input value C 1 , and obtains the second evaluation value E 2 from the second input value C 2 , and estimates the spin degree k 1 using a first map that defines the relationship between the first input value C 1 and the first evaluation value E 2 , and a second map that defines the relationship between the second input value C 2 and the second evaluation value E s . The first map and the second map are stored in advance in the memory or storage device of the control device 10.

[0044] FIG. 5(a) is an example of the first map, and FIG. 5(b) is an example of the second map. Each map is set as a graph with the input values C 1 , C 2 on the horizontal axis and the evaluation values E 1 , E 2 on the vertical axis. The maps shown in FIGS. 5(a) and (b) are, as described above, such that when the input values C 1 , C 2 are 0, the evaluation values E 1 , E 2 become 0, and as the absolute values of the input values C 1 , C 2 increase, the evaluation values E 1 , E​2 rises curvilinearly and steeply and the evaluation value E is equal to or greater than a predetermined absolute value 1 , E 2 is set to be 1. Note that if the minimum value and the maximum value of the two maps are the same, their characteristics (the way the evaluation value changes with respect to the input value) do not have to be the same.

[0045] The estimation unit 12 estimates that if the sum of the first evaluation value E 1 and the second evaluation value E 2 is 1 or less, the value (E 1 + E 2 ) is the spin degree k s , and if the value (E 1 + E 2 ) exceeds 1, it is estimated that the spin degree k s is 1.

[0046] The control unit 13 controls the actuator or the notification device 9 of the vehicle 1 based on the spin degree k s estimated by the estimation unit 12. The actuator controlled here is at least one of the above-described drive source 3, brake device 4, power steering device 5, AFS 6, ARS 7, and active suspension 8, and may be all of them. Note that the control unit 13 may also have a function of determining the lateral sliding state of the rear wheels 2R based on the spin degree k s . In this case, for example, the control unit 13 determines that if the spin degree k s is 0, the vehicle is not in a lateral sliding state (i.e., a normal driving state), and if the spin degree k s is not 0, it is determined that lateral sliding has occurred, and it can be determined that the greater the spin degree k s , the greater the degree of lateral sliding (the more slippery).

[0047] The control unit 13 controls the actuator so as to stabilize the behavior of the vehicle 1 as the spin degree k s increases. On the contrary, the control unit 13 controls the actuator so as to stabilize the behavior of the vehicle 1 as the spin degree k sWhen it is 0 (when in a normal driving state without spin behavior), the actuator is controlled according to the required torque demanded of the vehicle 1, the pedal operation by the driver, the vehicle body speed V, etc. The control at this time is called normal control. The normal control may be implemented by the control device 10 or by other in-vehicle control devices. The determination of whether to implement the normal control is made, for example, by the control unit 13 based on the spin degree k s and is determinable. Here, it is assumed that other in-vehicle control devices implement the normal control.

[0048] The control unit 13 of the present embodiment includes a first control unit 13A that adjusts the control amount of at least one of the driving force and the braking force of the vehicle 1 according to the spin degree k s When the first control unit 13A adjusts the control amount of the driving force, it sends a command to the control device of the drive source 3 to control the output (driving force) of the drive source 3. When the vehicle 1 is equipped with a power transmission device, the driving force may be adjusted by controlling the power transmission device. Also, when the first control unit 13A adjusts the control amount of the braking force, it sends a command to the control device of the brake device 4 to control the output (braking force) of the brake device 4. Since each wheel 2 of the brake device 4 can be individually controlled, finer adjustment is possible. It is also possible to adjust the control amount of the braking force by controlling the drive source 3.

[0049] When the normal control is being implemented, the first control unit 13A of the present embodiment adjusts the control amount so as not to inhibit the implementation of the normal control. On the other hand, when the normal control is not implemented, the first control unit 13A switches from the above normal control to a spin response control in which the distribution of the control amount to each wheel 2 is preset. The spin response control is a control for suppressing the spin behavior when the spin behavior occurs. For example, it controls to approach a preset driving force distribution and restricts the torque transfer in the front-rear and left-right directions by applying it to each wheel 2. Also in the spin response control, the sum of the driving force and the braking force of the vehicle 1 is determined according to the required torque demanded of the vehicle 1, the driver's pedal operation, etc. Note that the distribution itself does not necessarily have to be a fixed value and may be changed according to the driving state of the vehicle.

[0050] However, the first control unit 13A of the present embodiment changes the ratio at which the normal control contributes and the ratio at which the spin-corresponding control contributes according to the spin degree k s and adjusts the above control amount. Specifically, the first control unit 13A obtains a value obtained by subtracting the spin degree k s from 1 (1 - k s ) as a spin determination value (degree of lateral slip), calculates a required instruction torque as shown in FIG. 6, and obtains a control amount for each wheel 2 from the required instruction torque.

[0051] The first control unit 13A multiplies a value obtained by subtracting the required torque in the spin-corresponding control from the required torque in the normal control by the spin determination value, and calculates a value obtained by adding this product and the required torque in the spin-corresponding control as the required instruction torque. According to this calculation, when the spin determination value is 1 (i.e., k s = 0), the required torque is calculated as the required instruction torque as it is in the distribution of the normal control, and when the spin determination value is 0 (i.e., k s = 1), the required torque is distributed in the distribution of the spin-corresponding control and calculated as the required instruction torque. And when the spin determination value is between 0 and 1, a value obtained by adding the required torque in the normal control and the required torque in the spin-corresponding control at a predetermined ratio according to the numerical value is calculated as the required instruction torque. That is, by converging to the spin-corresponding control according to the decrease in the spin determination value (increase in the spin degree k s ), a stable operation is realized.

[0052] The control unit 13 of the present embodiment has a spin degree k sA second control unit 13B is included which adjusts at least one of the steering assist torque of the vehicle 1, the amount of steering of each wheel 2, and the control amount of at least one of the active suspensions 8 according to the situation. When controlling the steering assist torque, the second control unit 13B sends a command to the control device of the power steering device 5 to control the output (steering assist torque) of the power steering device 5. Also, when controlling the amount of steering, the second control unit 13B sends a command to the control devices of the AFS 6 and the ARS 7 to control the outputs (front wheel steering angle, rear wheel steering angle) of the AFS 6 and the ARS 7. Further, when controlling the active suspension 8, the second control unit 13B sends a command to the control device of the active suspension 8 to control an energy source such as hydraulic pressure, pneumatic pressure, or an electric motor.

[0053] The steering assist torque of the vehicle 1, the amount of steering of each wheel 2, and the active suspension 8 are all controlled according to the driver's steering operation, the vehicle body speed V, etc. during normal driving when no spin behavior occurs (i.e., during normal control), similar to the driving force and the braking force. When normal control is being carried out, the second control unit 13B of the present embodiment does not inhibit such implementation.

[0054] On the other hand, when normal control is not carried out, the second control unit 13B switches from normal control to second spin countermeasure control, for example, in the same manner as the above-described first control unit 13A. The second spin countermeasure control is a control for ensuring steering performance while suppressing the spin behavior when the spin behavior occurs, similar to the above-described spin countermeasure control. Regarding the second spin countermeasure control as well, the contribution degrees between normal control and the second spin countermeasure control may be adjusted using a spin determination value in the same manner as the above-described spin countermeasure control.

[0055] The combination of the control by the first control unit 13A and the control by the second control unit 13B is arbitrary. For example, it may be configured such that both the driving force and the braking force are controlled by the first control unit 13A, and the steering assist torque, the amount of steering, and the active suspension 8 are all controlled by the second control unit 13B. Alternatively, it may be configured such that only the braking force is controlled by the first control unit 13A and only the steering assist torque is controlled by the second control unit 13B. Or, it may be configured such that both the driving force and the braking force are controlled by the first control unit 13A and the control by the second control unit 13B is not performed. Thus, by using two or more controls in combination, the degree of freedom of control increases, and more precise vehicle motion control becomes possible.

[0056] Further, instead of or in addition to the control of the above actuator, the control unit 13 may control the notification device 9 according to the spin degree k s For example, when the spin degree k s becomes equal to or greater than a predetermined value, the control unit 13 may announce to the driver that spin behavior has occurred by voice or display, or may announce that control for suppressing the spin behavior is being performed.

[0057] [4. Flowchart] FIG. 7 shows an example of a flowchart implemented in the above-described control device 10. This flowchart is implemented at a predetermined calculation cycle, for example, when the main power supply of the vehicle 1 is on. First, in step S1, information from various sensors 21 to 23 is acquired. In step S2, the calculation unit 11 calculates the first input value C 1 and the second input value C 2 . Next, the estimation unit 12 obtains the first evaluation value E 1 and the second evaluation value E 2 (step S3), and the spin degree k 1 , E 2 is estimated from these two evaluation values E s (step S4). In the subsequent step S5, the control unit 13 (the first control unit 13A or the second control unit 13B) controls according to the spin degree k sBased on this, various controls are performed (step S5), and this flowchart is returned.

[0058] [5. Operation, Effect] In the above-described control device 10, the lateral acceleration A y and the first input value C representing the deviation from the product Vr of the vehicle body speed V and the yaw rate r 1 and the second input value C representing the amount of change over time of the deviation 2 are calculated, and based on these two input values C 1 , C 2 , the degree of spin k s is estimated.

[0059] In this way, based on the two input values C y indicating the deviation between the two time-series waveforms (i.e., the deviation between A 1 , C 2 and the increasing and decreasing tendency of this deviation, the degree of spin k s is estimated, so that the change in the transfer function, that is, the change in the rear-wheel cornering power K r can be easily and accurately evaluated from the time-series waveforms. Further, since the spin behavior can be quantified by the estimation method that does not use integration, and the actuator and the notification device 9 of the vehicle are controlled based on the index of the spin behavior (the degree of spin k s ), the controllability of the vehicle can be improved.

[0060] In particular, in the above-described embodiment, since the first input value C 1 is calculated as the value obtained by dividing the value obtained by subtracting the product Vr of the vehicle body speed V and the yaw rate r from the lateral acceleration A y by the lateral acceleration A y , and the second input value C 2 is calculated as the first-order differential value of the first input value C 1 , the influence of the amplitude of the input value (input amplitude) of the transfer function G(s) can be eliminated. Thereby, the evaluation accuracy of the change in the responsiveness (transfer function), that is, the change in the rear-wheel cornering power K r can be improved.

[0061] The above-described estimation unit 12 is the first input value C 1and the second input value C 2 A first evaluation value E for evaluating a deviation from each of them 1 and a second evaluation value E 2 are respectively obtained, and the first evaluation value E is applied to a prestored first map and second map 1 and the second evaluation value E 2 to estimate the degree of spin k s For this purpose, complex calculations and the like are unnecessary, and the control configuration can be simplified. Further, the magnitude of the deviation between the lateral acceleration A y and the product Vr of the vehicle body speed V and the yaw rate r can be grasped by the first map, and the time change rate (speed) of the deviation between the lateral acceleration A y and the product Vr of the vehicle body speed V and the yaw rate r can be grasped by the second map. Therefore, the estimation accuracy of the degree of spin k s can be improved.

[0062] In the control device 10 described above, at least one control amount of the driving force and the braking force of the vehicle 1 is adjusted according to the degree of spin k s Thus, by controlling according to the quantified degree of spin k s it is possible to increase, decrease, or adjust at least one control amount of the driving force and the braking force according to the degree of spin (decrease in grip) (for example, suppress torque transfer in the front, rear, left, and right directions when the grip is low). Thereby, it is possible to contribute to the suppression of spin behavior, and for example, to realize a target behavior.

[0063] According to the first control unit 13A described above, when spin behavior occurs, in order to switch from normal control to spin countermeasure control, the distribution of the control amount to each wheel 2 is set in advance, and spin behavior can be suppressed.

[0064] Furthermore, in the first control unit 13A described above, instead of simply switching between normal control and spin countermeasure control, the ratio contributed by normal control and the ratio contributed by spin countermeasure control are changed according to the degree of spin k s to adjust the control amount. Thereby, for example, the degree of spin k sAs it increases, it can be converged to spin-corresponding control, and stable operation can be realized.

[0065] Also, in the control device 10 described above, the spin degree k s According to, at least one of the control amounts of the steering assist torque of the vehicle 1, the steering amount of each wheel 2, and the active suspension 8 is adjusted. In this way, the quantified spin degree k s is estimated, and by increasing, decreasing, or adjusting at least one of the control amounts of the steering assist torque and the steering amount according to the degree of spin (decrease in grip), the controllability can be ensured. Also, by adjusting the control amount (hydraulic pressure or air pressure) of the active suspension 8, the grounding state of the wheel 2 can be controlled. By these, it can contribute to the suppression of spin behavior, and for example, the target behavior can be realized.

[0066] [6. Others] The configuration of the control device 10 described above is an example and is not limited to the above. For example, in the control device 10 above, two, the first control unit 13A and the second control unit 13B, are provided in the control unit 13, but these functions do not have to be separated. Also, the above six control targets (driving force, braking force, steering assist torque, steering amount, active suspension 8, notification device 9) may be controlled alone, or may be used in combination or combined. Also, the content of the spin-corresponding control is not limited to the above, and any control that can suppress the spin behavior may be used.

[0067] The above estimation unit 12 obtains the evaluation values E 1 , E 2 using the first map and the second map, but the method of obtaining the evaluation values E 1 , E 2 is not limited to the method using a map. Note that even when using a map, the specification of the map is not limited to those illustrated in FIGS. 5(a) and (b). Also, without obtaining the evaluation values E 1 , E 2 , the spin degree k 1 , C 2 from the two input values C s may be directly estimated.

[0068] Also, the configuration of the vehicle 1 to which the control device 10 is applied is also an example and is not limited to the above-described one. For example, when the vehicle 1 is equipped with an anti-skid control device (ASC; Active Stability Control), the ASC may be activated according to the skidding state determined by the above control device 10. Further, the AFS 6 and ARS 7 may be omitted from the vehicle 1, or a drive source 3 (for example, an in-wheel motor) may be provided for each wheel 2.

Explanation of Reference Numerals

[0069] 1 Vehicle 2 Wheel 2FL Left front wheel (front wheel, wheel) 2FR Right front wheel (front wheel, wheel) 2RL Left rear wheel (rear wheel, wheel) 2RR Right rear wheel (rear wheel, wheel) 3 Drive source (actuator) 4 Brake device (actuator) 5 Power steering device (actuator) 6 AFS (actuator) 7 ARS (actuator) 8 Active suspension (actuator) 9 Notification device 10 Control device 11 Calculation unit 12 Estimation unit 13 Control unit 13A First control unit 13B Second control unit 21 Vehicle speed sensor (vehicle body speed detection means) 22 Yaw rate sensor (yaw rate detection means) 23 Lateral acceleration sensor (lateral acceleration detection means) A y Lateral acceleration a 1 , b 1 , b 2 Coefficient C 1 First input value C2 Second input value E 1 First evaluation value E 2 Second evaluation value G Center of gravity G(s) Transfer function I Moment of inertia k s Degree of slip K f Front wheel cornering power K r Rear wheel cornering power L Wheelbase (distance between front and rear axles) L f Longitudinal distance between front axle and center of gravity L r Longitudinal distance between rear axle and center of gravity m Vehicle mass r Yaw rate V Vehicle body speed β Center of gravity slip angle δ Steering angle

Claims

1. In a control device for a vehicle provided with a vehicle body speed detection means for detecting the vehicle body speed of the vehicle, a yaw rate detection means for detecting the yaw rate of the vehicle, and a lateral acceleration detection means for detecting the lateral acceleration of the vehicle, a calculation unit that calculates a first input value representing the deviation between the lateral acceleration and the product of the vehicle body speed and the yaw rate, and a second input value representing the amount of change over time of the deviation; an estimation unit that estimates a degree of spin as an index representing the spin behavior of the vehicle based on the first input value and the second input value; a control unit that controls an actuator or a notification device of the vehicle based on the degree of spin, characterized in that it is a control device for a vehicle.

2. The estimation unit respectively obtains a first evaluation value and a second evaluation value for evaluating the deviation from each of the first input value and the second input value, and uses a first map defining the relationship between the first input value and the first evaluation value, and a second map defining the relationship between the second input value and the second evaluation value to estimate the degree of spin characterized in that it is the control device for a vehicle according to claim 1.

3. The control unit includes a first control unit that adjusts at least one of the control amounts of the driving force and the braking force of the vehicle according to the degree of spin. characterized in that it is the control device for a vehicle according to claim 1 or 2.

4. When the first control unit determines from the degree of spin that the spin behavior is occurring, it switches from the normal control implemented when the spin behavior is not occurring to a spin countermeasure control in which the distribution of the control amount to each wheel of the vehicle is preset. characterized in that it is the control device for a vehicle according to claim 3.

5. The first control unit changes the ratio contributed by the normal control and the ratio contributed by the spin countermeasure control according to the degree of spin, and adjusts the control amount. characterized in that it is the control device for a vehicle according to claim 4.

6. The control unit includes a second control unit that adjusts at least one of the control amounts of the steering assist torque of the vehicle, the amount of steering of each wheel of the vehicle, and the active suspension according to the degree of spin. characterized in that it is the control device for a vehicle according to claim 1 or 2.

7. The control unit includes a second control unit that adjusts at least one of the steering assist torque of the vehicle, the turning angle of each wheel of the vehicle, and the control amount of the active suspension according to the degree of spin. The vehicle control device according to claim 5, characterized in that.

8. The first input value is a value obtained by dividing a value obtained by subtracting the product from the lateral acceleration by the lateral acceleration. The second input value is a first derivative value of the first input value. The vehicle control device according to claim 1 or 2, characterized in that.

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