Vehicle behavior control device

Abstract

Abnormalities in the acceleration detection means can be detected with an inexpensive configuration. [Solution] A state quantity comparison and selection processing unit 31 compares a first state quantity based on an acceleration physical quantity, a second state quantity based on a wheel speed, and a third state quantity based on a detection value of an IMU 11. The state quantity comparison and selection processing unit 31 determines a normal state when the values ​​of the first state quantity, second state quantity, and third state quantity are within a predetermined range. The state quantity comparison and selection processing unit 31 determines an abnormal state when the value of one of the first state quantity, second state quantity, and third state quantity is outside the predetermined range for at least two other values. The state quantity comparison and selection processing unit 31 and the damping force control unit 32 control the variable damper 7 based on the first state quantity unless the first state quantity is abnormal. When the first state quantity is abnormal, the state quantity comparison and selection processing unit 31 and the damping force control unit 32 control the variable damper 7 based on the third state quantity.

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle behavior control device that controls a force generating mechanism provided between a body and a wheel of a vehicle. [Background technology]

[0002] Patent Document 1 discloses a configuration for a railway shock absorber in which the temperatures of the solenoids of at least three or more adjustable damping force shock absorbers are compared and an abnormality is determined when the temperature of one solenoid is outside a predetermined temperature range relative to the temperatures of at least two or more other solenoids. Patent Document 2 discloses a configuration in which three identical lean angle sensors are used to configure the system as a redundant system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-22880 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-157527 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, there is a demand for inexpensive detection of abnormalities in sensors that actually measure vehicle behavior. In response to this demand, the systems disclosed in Patent Documents 1 and 2 are configured to include three or more identical sensors to detect sensor abnormalities and back up the control system. However, a configuration that includes multiple identical sensors, for example to back up the control system, increases manufacturing costs.

[0005] An object of one embodiment of the present invention is to provide a vehicle behavior control device that is inexpensively configured and capable of determining whether an abnormality in acceleration detection means exists. [Means for solving the problem]

[0006] One embodiment of the present invention is a vehicle behavior control device that controls a force generating mechanism that is provided between a body and wheels of a vehicle and generates an adjustable force between the body and the wheels, and includes: acceleration detection means that detects an acceleration physical quantity related to the acceleration of the vehicle; a first state quantity calculation unit that calculates a first state quantity of vehicle behavior from the acceleration physical quantity; a second state quantity calculation unit that calculates a second state quantity of vehicle behavior from a detection value of wheel speed detection means that detects the rotational speed of the wheels; a third state quantity calculation unit that calculates a third state quantity of vehicle behavior from a detection value of vehicle motion detection means that detects six-axis momentum of the vehicle; and an abnormality judgment unit that compares values ​​of the first state quantity, the second state quantity, and the third state quantity, and determines that an abnormality exists when one of the values ​​is outside a predetermined range for at least two values, and controls based on the first state quantity except when the first state quantity is abnormal, and controls based on the third state quantity when the first state quantity is abnormal. [Effects of the Invention]

[0007] According to one embodiment of the present invention, it is possible to determine whether an abnormality in the acceleration detection means is present using an inexpensive configuration. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram showing a vehicle to which a vehicle behavior control device according to an embodiment of the present invention is applied; [Figure 2] FIG. 2 is a block diagram showing a damper control unit in FIG. [Figure 3] 10 is a flowchart showing a state quantity comparison and selection process performed by a state quantity comparison and selection processing unit. [Figure 4] FIG. 10 is an explanatory diagram showing an example of a neural network of a second sprung / unsprung state quantity calculation unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle behavior control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the vehicle behavior control device is applied to a four-wheeled vehicle.

[0010] Fig. 1 shows a vehicle 1 to which a vehicle behavior control device 20 is applied. The vehicle 1 includes, for example, a suspension device 5, a sprung acceleration sensor 9, an unsprung acceleration sensor 10, an IMU 11, and a controller 21 (ECU). In Fig. 1, for example, left and right front wheels and left and right rear wheels (hereinafter collectively referred to as wheels 3) are provided on the underside of a vehicle body 2 that constitutes the body of the vehicle. The wheels 3 include tires 4, which act as springs that absorb small irregularities in the road surface.

[0011] The suspension device 5 is a shock absorber provided in the vehicle 1. The suspension device 5 is provided between the vehicle body 2 and the wheels 3. The suspension device 5 is composed of a suspension spring 6 (hereinafter referred to as the spring 6) and an adjustable damping force shock absorber (hereinafter referred to as the variable damper 7) provided in parallel with the spring 6 between the vehicle body 2 and the wheels 3.

[0012] 1 shows a case where one set of suspension devices 5 is provided between the vehicle body 2 and the wheels 3. However, a total of four sets of suspension devices 5 are provided individually and independently between, for example, four wheels 3 and the vehicle body 2, and only one of these sets is shown schematically in FIG.

[0013] Here, the variable damper 7 of the suspension device 5 is configured using a damping force adjustable hydraulic shock absorber interposed between the vehicle body 2 and the wheel 3. The variable damper 7 is a force generating mechanism of the suspension device 5. The variable damper 7 is provided between the vehicle body 2 and the wheel 3, and constitutes a relative displacement suppression device that changes the force that suppresses the relative displacement between the vehicle body 2 and the wheel 3.

[0014] The variable damper 7 is provided with a variable damping force actuator 8, which is composed of a damping force adjustment valve or the like, for continuously adjusting the characteristics of the generated damping force (i.e., the damping force characteristics) from hard characteristics (hard characteristics) to soft characteristics (soft characteristics). Note that the variable damping force actuator 8 does not necessarily have to be configured to continuously adjust the damping force characteristics, and may be capable of adjusting the damping force in multiple stages, for example, two or more stages. Furthermore, the variable damper 7 may be of a pressure control type or a flow rate control type. The variable damper 7 may also be of a type that controls viscosity, such as a magnetorheological fluid or an electrorheological fluid.

[0015] The sprung acceleration sensor 9 is provided on the vehicle body 2 and detects vertical vibration acceleration on the vehicle body 2 side, which is the sprung side. The sprung acceleration sensor 9 is attached to the vehicle body 2, for example, at a position near the upper ends of the variable dampers 7. For example, a total of three sprung acceleration sensors 9 are provided on the vehicle body 2. In this case, the sprung acceleration sensors 9 are attached to the vehicle body 2, for example, at positions near the upper ends of the variable dampers 7 on the left and right front wheel sides, and at a midpoint between the left and right rear wheels. The sprung acceleration sensor 9 detects vertical vibration acceleration (sprung acceleration) on the vehicle body 2 side, which is the sprung side, as an acceleration physical quantity related to the acceleration of the vehicle 1. The sprung acceleration sensor 9 outputs a detection signal of the sprung acceleration to the controller 21.

[0016] The controller 21 can geometrically calculate the sprung acceleration of each wheel based on the detection signals from the three sprung acceleration sensors 9. That is, if the vehicle body 2, which is the sprung mass, is considered to be a rigid body, the sprung acceleration of each wheel can be geometrically calculated based on the sprung acceleration detected at three points on the vehicle body 2.

[0017] The unsprung acceleration sensor 10 is provided on the wheel 3 side, which is the unsprung side. For example, a total of two unsprung acceleration sensors 10 are provided on the vehicle 1. Specifically, for example, the unsprung acceleration sensors 10 are provided on the right front wheel and the left front wheel of the vehicle 1, respectively. The unsprung acceleration sensor 10 detects vertical vibration acceleration (unsprung acceleration) on the wheel 3 side, which is the unsprung side, as an acceleration physical quantity related to the acceleration of the vehicle 1. The unsprung acceleration sensor 10 outputs a detection signal of the unsprung acceleration to the controller 21.

[0018] The controller 21 can calculate the unsprung acceleration on the rear wheel side based on the detection signal from the front wheel side unsprung acceleration sensor 10. That is, when the vehicle 1 is moving forward, the controller 21 can calculate the unsprung acceleration on the rear wheel side based on the unsprung acceleration on the front wheel side by taking into account the time delay according to the wheelbase.

[0019] The inertial measurement unit 11 (hereinafter referred to as IMU 11) is a vehicle motion detection means that detects six-axis momentum of the vehicle 1. The IMU 11 is provided on the vehicle body 2, which is the so-called sprung part. The IMU 11 includes, for example, a three-axis angular velocity sensor and a three-axis acceleration sensor. The IMU 11 is a multi-purpose sensor provided in the vehicle 1. The detection signal of the IMU 11 is used for, for example, traction control, braking control, anti-skid control, automatic driving control, etc. of the vehicle 1.

[0020] The IMU 11 is attached to an arbitrary sensor position on the vehicle body 2. The IMU 11 detects the sprung acceleration in the vertical direction at the sensor position, the roll rate which is the angular velocity in the roll direction, and the pitch rate which is the angular velocity in the pitch direction, and outputs the detection signals to a controller 21 described below. By knowing the attachment position (sensor position) of the IMU 11 in advance, the controller 21 can grasp the vehicle motion. That is, if the vehicle body 2, which is a sprung body, is considered a rigid body, the sprung absolute vertical velocity (sprung velocity) of each wheel can be geometrically calculated based on the sprung acceleration, roll rate, and pitch rate detected at an arbitrary point on the vehicle body 2. The sensor position of the IMU 11 may be, for example, the center of gravity of the vehicle body 2 or a position other than the center of gravity.

[0021] The CAN 12 (Controller Area Network) is connected to the controller 21 and also to a wheel speed sensor 13 that detects the rotation speed of the wheels 3. The CAN 12 is also connected to various multi-purpose sensors that the vehicle has, such as a vehicle speed sensor and a steering angle sensor. The CAN 12 transmits various types of vehicle information including the rotation speed (wheel speed) of the wheels 3 and the vehicle speed, which is the speed of the vehicle. This allows the controller 21 to obtain information such as the wheel speed and vehicle speed through the CAN 12.

[0022] In this embodiment, the CAN is used as an example of the in-vehicle network, but other in-vehicle networks may be used, such as CAN FD (CAN with Flexible Data Rate), FlexRay, or in-vehicle Ethernet.

[0023] The vehicle behavior control device 20 controls a variable damper 7 (force generating mechanism) that is provided between a vehicle body 2 and wheels 3 of the vehicle 1 and generates an adjustable force between the vehicle body 2 and the wheels 3. The vehicle behavior control device 20 includes a sprung acceleration sensor 9 and an unsprung acceleration sensor 10 as acceleration detection means, and a controller 21 that has a first sprung / unsprung state quantity calculation unit 28 (first state quantity calculation unit), a second sprung / unsprung state quantity calculation unit (second state quantity calculation unit), a third sprung / unsprung state quantity calculation unit (third state quantity calculation unit), a state quantity comparison / selection processing unit 31, and a damping force control unit 32.

[0024] The controller 21 is a control device that controls the damping characteristics of the variable damper 7 and is configured, for example, by a microcomputer. The controller 21 has a storage unit 22 that includes a ROM, a RAM, a non-volatile memory, etc. Various programs, information (sensor positions, vehicle specification information), data, etc. for controlling the variable damper 7 are stored in the storage unit 22 of the controller 21. The input side of the controller 21 is connected to the sprung acceleration sensor 9, the unsprung acceleration sensor 10, and the IMU 11, and is also connected to, for example, a CAN 12, which is a line network required for data communication. The output side of the controller 21 is connected to the variable damping force actuator 8 of the variable damper 7.

[0025] The controller 21 calculates (estimates) the sprung velocity and the relative velocity as first state quantities based on data acquired from the sprung acceleration sensor 9 and the unsprung acceleration sensor 10. At this time, the relative velocity is the relative velocity (stroke velocity) between the sprung and unsprung portions, and is the piston velocity of the variable damper 7. The controller 21 determines the force to be generated by the variable damper 7 (force generating mechanism) of the suspension device 5 based on the estimated vehicle state quantities, and outputs a control signal (command current) to the damping force variable actuator 8 of the suspension device 5.

[0026] The controller 21 calculates (estimates) a second state quantity (sprung speed, relative speed) as a vehicle behavior from, for example, the detection value of the wheel speed sensor 13. The controller 21 calculates (estimates) a third state quantity (sprung speed, relative speed) as a vehicle momentum from the detection value of the IMU 11.

[0027] The controller 21 compares the first state quantity, the second state quantity, and the third state quantity to determine whether the acceleration physical quantities (sprung acceleration, unsprung acceleration) acquired from the sprung acceleration sensor 9 and the unsprung acceleration sensor 10 are abnormal. The controller 21 controls the variable damper 7 based on the acceleration physical quantity unless the acceleration physical quantity is abnormal. That is, when the acceleration physical quantity is normal, the controller 21 controls the variable damper 7 based on the first state quantity calculated from the acceleration physical quantity. When the acceleration physical quantity is abnormal, the controller 21 controls the variable damper 7 based on the vehicle motion estimated value (third state quantity) estimated from the detection value of the IMU 11.

[0028] 1 and 2, the controller 21 includes a damper control unit 23, a weight parameter storage unit 24, and a data reading unit 25. The damper control unit 23 includes a receiving unit 26, a vehicle state quantity calculation unit 27, and a damping force control unit 32. The weight parameter storage unit 24 may be a part of the storage unit 22, or may be separate from the storage unit 22.

[0029] The receiver 26 acquires sprung acceleration data from the sprung acceleration sensor 9 and unsprung acceleration data from the unsprung acceleration sensor 10. The receiver 26 acquires data on sprung acceleration, roll rate, and pitch rate at the sensor position from the IMU 11. The receiver 26 acquires data related to vehicle behavior (hereinafter referred to as behavior information) via the CAN 12. At this time, the behavior information includes, for example, longitudinal acceleration (longitudinal G), lateral acceleration (lateral G), steering angle, yaw rate, wheel speed of each vehicle, etc. Note that the controller 21 does not need to acquire data directly from the sprung acceleration sensor 9, unsprung acceleration sensor 10, and IMU 11, but may acquire the data via the CAN 12.

[0030] The vehicle state quantity calculation unit 27 calculates (estimates) sprung speed and relative speed as vehicle state quantities based on data acquired from, for example, the sprung acceleration sensor 9, the unsprung acceleration sensor 10, the IMU 11, and the CAN 12. The vehicle state quantity calculation unit 27 includes a first sprung / unsprung state quantity calculation unit 28, a second sprung / unsprung state quantity calculation unit 29, a third sprung / unsprung state quantity calculation unit 30, and a state quantity comparison and selection processing unit 31. The vehicle state quantity calculation unit 27 estimates data related to suspension control required by the damping force control unit 32, specifically, instantaneous values ​​related to suspension control (sprung speed, relative speed), based on data acquired from the sprung acceleration sensor 9, the unsprung acceleration sensor 10, the IMU 11, and the CAN 12.

[0031] The first sprung / unsprung state quantity calculation unit 28 is a first state quantity calculation unit that calculates first state quantities of vehicle behavior (sprung velocity, relative velocity) from acceleration physical quantities (sprung acceleration, unsprung acceleration). The first sprung / unsprung state quantity calculation unit 28 includes, for example, a subtractor and an integrator (neither of which are shown). The first sprung / unsprung state quantity calculation unit 28 receives the sprung acceleration and unsprung acceleration from the receiving unit 26. The first sprung / unsprung state quantity calculation unit 28 integrates the sprung acceleration of each wheel to determine the sprung velocity of each wheel. At this time, the first sprung / unsprung state quantity calculation unit 28 includes a filter (not shown) for compensating for the phase of the output signal. For this reason, the first sprung / unsprung state quantity calculation unit 28 integrates the sprung acceleration of each wheel, performs filtering, and calculates the sprung velocity of each wheel.

[0032] Furthermore, first sprung / unsprung state quantity calculation unit 28 subtracts the unsprung acceleration from the sprung acceleration of each wheel to determine the relative acceleration, which is the difference between these. First sprung / unsprung state quantity calculation unit 28 integrates the relative acceleration to determine the relative velocity (stroke velocity) of each wheel. When determining the relative velocity, filter processing is performed to compensate for the phase of the output signal, just as when determining the sprung velocity. For this reason, first sprung / unsprung state quantity calculation unit 28 integrates the relative acceleration of each wheel and performs filter processing to calculate the sprung velocity of each wheel. First sprung / unsprung state quantity calculation unit 28 outputs the sprung velocity and relative velocity of each wheel as the first state quantity.

[0033] The second sprung / unsprung state quantity calculation unit 29 estimates the sprung speed and relative speed as second state quantities based on the wheel speeds. The second sprung / unsprung state quantity calculation unit 29 is a second state quantity calculation unit (vehicle behavior estimation unit) that calculates (estimates) a second state quantity of the vehicle behavior from the detection value of the wheel speed sensor 13 serving as wheel speed detection means that detects the rotational speed of the wheel 3. The second sprung / unsprung state quantity calculation unit 29 is, for example, artificial intelligence (AI). The second sprung / unsprung state quantity calculation unit 29 estimates the sprung speed and relative speed of each wheel as vehicle behavior based on the wheel speeds, etc.

[0034] As an example, a specific configuration of the second sprung / unsprung state quantity calculation unit 29 will be described with reference to FIG. 4. As shown in FIG. 4, the second sprung / unsprung state quantity calculation unit 29 is configured, for example, by a neural network. The neural network is configured as a three-layer hierarchical neural network in which elements of an input layer (number of elements i) 101, a hidden layer (number of elements j) 102, and an output layer (number of elements k) 103 are hierarchically connected. Each element of the input layer 101 is connected to each element of the hidden layer 102 by a weight W1ij (i = 1 to I, j = 1 to J), and each element of the hidden layer 102 is connected to each element of the output layer 103 by a weight W2jk (j = 1 to J, k = 1 to K). Information on these weights (hereinafter referred to as weight parameters) is expressed as a determinant of the weights W1ij and W2jk. The weight parameters are obtained in advance by machine learning and stored in the weight parameter storage unit 24. Although this example shows a neural network with a single, all-element-connected hidden layer 102, which is the simplest possible configuration, the present invention is not limited to this. For example, a neural network with two or more hidden layers 102 may also be used.

[0035] The neural network machine learning is performed based on data on vehicle state quantities (sprung speed, unsprung speed) acquired in advance by a data acquisition vehicle and data on behavior information including wheel speed. The data acquisition vehicle in advance has the same specifications as the vehicle in which second sprung / unsprung state quantity calculation unit 29 is installed, and is equipped with various sensors (wheel speed sensor, acceleration sensor, etc.) that acquire vehicle state quantities. In the neural network machine learning, weight parameters are adjusted to learn the correlation between the vehicle state quantity data (sprung speed, unsprung speed) acquired by the data acquisition vehicle and the behavior information data. The weight parameters obtained as a result of learning are stored in weight parameter memory unit 24.

[0036] In the present embodiment, second sprung / unsprung state quantity calculation unit 29 performs machine learning to determine the correlation between vehicle state quantity data and behavior information data acquired by a data acquisition vehicle, but the present invention is not limited to this. For example, a vehicle model corresponding to the vehicle on which second sprung / unsprung state quantity calculation unit 29 is installed may be constructed, and second sprung / unsprung state quantity calculation unit 29 may perform machine learning based on data acquired by a simulation using this vehicle model.

[0037] Time-series data such as the wheel speed of each wheel and the longitudinal acceleration of the vehicle are input to the input layer 101 of the neural network. The output layer 103 outputs, for example, instantaneous values ​​of the sprung and unsprung velocities of the suspension device 5 assumed to be attached to each wheel 3 of the vehicle. The number of elements in the hidden layer 102 is generally determined from the number of elements in the input layer 101 and the output layer 103, but is set to a number that maximizes the accuracy of vehicle behavior estimation by the neural network. The number of elements in the output layer 103 is determined by the output specifications of the vehicle behavior estimation.

[0038] The second sprung / unsprung state quantity calculation unit 29 acquires the sprung speed and relative speed of each wheel based on the estimated sprung speed and unsprung speed of each wheel. At this time, the relative speed is calculated as the difference between the sprung speed and the unsprung speed. The second sprung / unsprung state quantity calculation unit 29 outputs the sprung speed and relative speed of each wheel as the second state quantity.

[0039] The third sprung / unsprung state quantity calculation unit 30 estimates the sprung velocity and the relative velocity as the third state quantity based on the vehicle momentum from the detection value of the IMU 11. The third sprung / unsprung state quantity calculation unit 30 is a third state quantity calculation unit (vehicle motion estimation unit) that estimates the third state quantity (vehicle momentum) from the detection value of the IMU 11 (vehicle motion detection means) that detects the six-axis momentum of the vehicle 1.

[0040] The third sprung / unsprung state quantity calculation unit 30 calculates the vertical sprung acceleration of each wheel based on the data acquired by the receiving unit 26 from the IMU 11, the sensor position of the IMU 11, and vehicle specification information such as the shape, size, weight, wheelbase, and positions of each wheel 3. Specifically, the third sprung / unsprung state quantity calculation unit 30 calculates the roll angular acceleration (roll rate) and pitch angular acceleration (pitch rate) at the sensor position from the data acquired from the IMU 11, and also calculates the vertical sprung acceleration of each wheel based on the sprung acceleration, roll angular acceleration, and pitch angular acceleration at the sensor position and the relationship between the sensor position and the position (tire position) of each wheel 3. The third sprung / unsprung state quantity calculation unit 30 includes an IMU signal conversion unit that converts the signal (IMU signal) output from the IMU 11 into the sprung acceleration at the tire position.

[0041] The third sprung / unsprung state quantity calculation unit 30 calculates the relative speed (stroke speed) of the suspension device 5 of each wheel using a mathematical model of the vehicle 1 that receives as input values ​​indicating the sprung acceleration of each wheel and the force (damping force) generated by the variable damper 7. In this case, the third sprung / unsprung state quantity calculation unit 30 is an artificial intelligence model constructed by, for example, machine learning. In other words, the mathematical model of the vehicle 1 is an artificial intelligence (AI) model.

[0042] The third sprung / unsprung state quantity calculation unit 30 calculates the damping force generated by the variable damper 7 based on the calculated stroke speed and the command current value output from the damping force control unit 32. The third sprung / unsprung state quantity calculation unit 30 calculates the stroke speed of the suspension device 5 for each wheel based on the sprung acceleration of each wheel and the calculated damping force. Specifically, the third sprung / unsprung state quantity calculation unit 30 receives the sprung acceleration of each wheel and the damping force of the variable damper 7 as input, and estimates the stroke speed of each wheel using a neural network that has been trained to estimate the stroke speed of each wheel. The third sprung / unsprung state quantity calculation unit 30 reads out weight parameters stored in the weight parameter memory unit 24 via the data reading unit 25. The third sprung / unsprung state quantity calculation unit 30 estimates the stroke speed based on the sprung acceleration, the damping force, and the weight parameters.

[0043] The neural network of the third sprung / unsprung state quantity calculation unit 30 is configured similarly to the neural network of the second sprung / unsprung state quantity calculation unit 29. Machine learning of the neural network is performed based on data on vehicle state quantities (sprung speed, unsprung speed) acquired in advance by a data acquisition vehicle, and data on the sprung acceleration of each wheel and the damping force of the variable damper 7. Without being limited to this, for example, a vehicle model corresponding to the vehicle on which the third sprung / unsprung state quantity calculation unit 30 is installed may be constructed, and the third sprung / unsprung state quantity calculation unit 30 may perform machine learning of the neural network based on data acquired by a simulation using this vehicle model.

[0044] The weight parameters of the trained neural network are stored in the weight parameter storage unit 24. Therefore, the neural network of the third sprung / unsprung state quantity calculation unit 30 is configured using the weight parameters stored in the weight parameter storage unit 24.

[0045] Furthermore, the third sprung / unsprung state quantity calculation unit 30 calculates the sprung speed of each wheel of the vehicle, for example, by integrating the sprung acceleration of each wheel. At this time, the third sprung / unsprung state quantity calculation unit 30 is provided with a filter (not shown) for compensating the phase of the output signal. Therefore, the third sprung / unsprung state quantity calculation unit 30 integrates the sprung acceleration of each wheel and performs filtering to calculate the sprung speed of each wheel. The third sprung / unsprung state quantity calculation unit 30 outputs the sprung speed and relative speed of each wheel as the third state quantity.

[0046] The state quantity comparison and selection processing unit 31 and the damping force control unit 32 constitute an abnormality determination unit. The state quantity comparison and selection processing unit 31 compares a first state quantity (sprung speed, relative speed) based on acceleration physical quantities (sprung acceleration, unsprung acceleration), a second state quantity (sprung speed, relative speed) as a vehicle behavior value based on wheel speed (detected value of wheel speed sensor 13), and a third state quantity (sprung speed, relative speed) as a vehicle motion estimated value based on vehicle motion quantity (detected value of IMU 11). The state quantity comparison and selection processing unit 31 determines a normal state when the values ​​of the first state quantity, second state quantity, and third state quantity are all within a predetermined range. On the other hand, the state quantity comparison and selection processing unit 31 determines a normal state when the value of one of the first state quantity, second state quantity, and third state quantity is outside the predetermined range for at least two of the other values. In this case, the predetermined range is a range within which each state quantity can be determined to be normal and is set appropriately taking into account the actual detected value, calculated value, etc.

[0047] When the state quantity comparison and selection processing unit 31 determines that there is a normal state, it selects the first state quantity and outputs it to the damping force control unit 32. On the other hand, when the state quantity comparison and selection processing unit 31 determines that there is an abnormality, it selects the first state quantity and outputs it to the damping force control unit 32 unless the first state quantity is abnormal. Furthermore, when the state quantity comparison and selection processing unit 31 determines that there is an abnormality, if the first state quantity is abnormal, it selects the third state quantity and outputs it to the damping force control unit 32. When the state quantity comparison and selection processing unit 31 determines that there is an abnormality, it identifies the abnormal state quantity or sensor and outputs the identified content as failure information.

[0048] The state quantity comparison and selection processing unit 31 and the damping force control unit 32 control the variable damper 7 based on the first state quantity unless the first state quantity is abnormal. When the first state quantity is abnormal, the state quantity comparison and selection processing unit 31 and the damping force control unit 32 control the variable damper 7 based on the third state quantity (vehicle motion estimated value).

[0049] The damping force control unit 32 is a control amount determination unit that determines a control amount for controlling the variable damper 7 from the sprung speed and the relative speed. The damping force control unit 32 calculates a control command value (command current value) for controlling the damping force of the variable damper 7 of the suspension device 5 based on the sprung speed and the relative speed selected by the state quantity comparison and selection processing unit 31. At this time, the control amount for controlling the variable damper 7 is the control command value for controlling the damping force of the variable damper 7. Specifically, the damping force control unit 32 calculates a command current value as a control command value for improving the ride comfort of the vehicle based on, for example, bilinear optimal control, skyhook control, H∞ control, etc. The damping force control unit 32 outputs a command current as a control signal to the damping force variable actuator 8 of the variable damper 7 based on the command current value. Note that the control amount determination unit may calculate a control command value for improving not only the ride comfort of the vehicle but also the handling stability.

[0050] Next, the state quantity comparison and selection process by the state quantity comparison and selection processing unit 31 will be described with reference to Fig. 3. Each step in the flowchart shown in Fig. 3 is represented by the letter "S" (for example, step 1 is represented by "S1").

[0051] In S1, the state quantity comparison and selection processing unit 31 compares the values ​​of the first state quantity, the second state quantity, and the third state quantity, which are made up of the sprung speed and the relative speed. Specifically, the state quantity comparison and selection processing unit 31 determines whether the difference between the values ​​of these three state quantities is within a predetermined range. If the difference between the values ​​of the three state quantities is within the predetermined range, the state quantity comparison and selection processing unit 31 determines that the first state quantity, the second state quantity, and the third state quantity are all normal.

[0052] On the other hand, if the difference between the values ​​of the three state quantities is outside a predetermined range, the state quantity comparison and selection processing unit 31 performs a majority vote on the three state quantities. For example, if the difference between the values ​​of the first and second state quantities is within a predetermined range and only the value of the third state quantity is outside the predetermined range, the state quantity comparison and selection processing unit 31 determines that the first and second state quantities are normal but the third state quantity is abnormal. Similarly, if the difference between the values ​​of the first and third state quantities is within a predetermined range and only the value of the second state quantity is outside the predetermined range, the state quantity comparison and selection processing unit 31 determines that the first and third state quantities are normal but the second state quantity is abnormal. If the difference between the values ​​of the second and third state quantities is within a predetermined range and only the value of the first state quantity is outside the predetermined range, the state quantity comparison and selection processing unit 31 determines that the second and third state quantities are normal but the first state quantity is abnormal.

[0053] In S2, the state quantity comparison and selection processing unit 31 determines whether or not the G sensors (sprung acceleration sensor 9, unsprung acceleration sensor 10) are abnormal. Specifically, if the state quantity comparison and selection processing unit 31 determines that the first state quantity is abnormal in S1, it determines that the G sensors are abnormal ("YES" in S2) and proceeds to S3.

[0054] In S3, the state quantity comparison and selection processing unit 31 outputs failure information and executes G-sensor abnormality processing. G-sensor abnormality processing includes various error processing, such as stopping control based on the detection value of the G-sensor, excluding the first state quantity from the majority voting processing in S1, and prompting the user to repair the G-sensor. After executing the G-sensor abnormality processing in S3, the process proceeds to S4. In S4, the state quantity comparison and selection processing unit 31 selects a third state quantity based on the detection value of the IMU 11 and outputs it to the damping force control unit 32. At this time, the damping force control unit 32 controls the damping force of the variable damper 7 based on the third state quantity.

[0055] In S2, if the state quantity comparison and selection processing unit 31 determines that the first state quantity is normal in S1, it determines that the G sensor is normal ("NO" in S2) and proceeds to S5. In S5, the state quantity comparison and selection processing unit 31 determines whether or not the IMU 11 is abnormal. Specifically, if the state quantity comparison and selection processing unit 31 determines that the third state quantity is abnormal in S1, it determines that the IMU 11 is abnormal ("YES" in S5) and proceeds to S6.

[0056] In S6, the state quantity comparison and selection processing unit 31 outputs failure information and executes abnormality processing for the IMU 11. The abnormality processing for the IMU 11 includes various error processing such as stopping control based on the detection value of the IMU 11, excluding the third state quantity from the majority voting processing in S1, and prompting the user to repair the IMU 11. After executing the abnormality processing for the IMU 11 in S6, the process proceeds to S7. In S7, the state quantity comparison and selection processing unit 31 selects a first state quantity based on the detection value of the G sensor and outputs it to the damping force control unit 32. At this time, the damping force control unit 32 controls the damping force of the variable damper 7 based on the first state quantity.

[0057] In S5, if the state quantity comparison and selection processing unit 31 determines that the third state quantity is normal in S1, it determines that the IMU 11 is normal ("NO" in S5) and proceeds to S8. In S8, the state quantity comparison and selection processing unit 31 determines whether the wheel speed is abnormal. Specifically, if the state quantity comparison and selection processing unit 31 determines that the second state quantity is abnormal in S1, it determines that the wheel speed is abnormal ("YES" in S8) and proceeds to S9.

[0058] In S9, the state quantity comparison and selection processing unit 31 outputs failure information and executes wheel speed abnormality processing. The wheel speed abnormality processing executes various error processing such as stopping control based on the wheel speed, excluding the second state quantity from the majority voting processing in S1, and prompting the user to repair the wheel speed sensor 13, and then the process proceeds to S10. In S10, the state quantity comparison and selection processing unit 31 selects a first state quantity based on the detection value of the G sensor and outputs it to the damping force control unit 32. At this time, the damping force control unit 32 controls the damping force of the variable damper 7 based on the first state quantity.

[0059] Furthermore, in S8, if the state quantity comparison and selection processing unit 31 determines that the second state quantity is normal in S1, it determines that the wheel speed is normal ("NO" in S8), and proceeds to S11. In S11, the state quantity comparison and selection processing unit 31 selects the first state quantity based on the detection value of the G sensor, and outputs it to the damping force control unit 32. At this time, the damping force control unit 32 controls the damping force of the variable damper 7 based on the first state quantity.

[0060] Thus, the vehicle behavior control device 20 according to this embodiment includes acceleration detection means (sprung acceleration sensor 9, unsprung acceleration sensor 10) for detecting acceleration physical quantities (sprung acceleration, unsprung acceleration) related to the acceleration of the vehicle 1, a first state quantity calculation unit (first sprung / unsprung state quantity calculation unit 28) for calculating a first state quantity of the vehicle behavior from the acceleration physical quantities, a second state quantity calculation unit (second sprung / unsprung state quantity calculation unit 29) for calculating a second state quantity of the vehicle behavior from the detection value of wheel speed detection means (wheel speed sensor 13) for detecting the rotational speed of the wheels 3, and six-axle steering of the vehicle 1. The system is equipped with a third state quantity calculation unit (third sprung / unsprung state quantity calculation unit 30) that calculates a third state quantity of the vehicle behavior from the detection value of a vehicle movement detection means (IMU 11) that detects movement, and an abnormality determination unit (state quantity comparison and selection processing unit 31, damping force control unit 32) that compares the values ​​of the first state quantity, the second state quantity, and the third state quantity, and determines that there is an abnormality when one of these values ​​is outside a predetermined range with respect to at least the remaining two values, and controls based on the first state quantity except when the first state quantity is abnormal, and controls based on the third state quantity when the first state quantity is abnormal.

[0061] The vehicle behavior control device 20 includes a second sprung / unsprung state quantity calculation unit 29 that calculates the second state quantity from the wheel speed, and thereby can determine whether or not a sensor is abnormal by comparing a first state quantity based on the acceleration physical quantity with a third state quantity based on the detection value of the IMU 11. Therefore, when an abnormal sensor is found, the detection value of the abnormal sensor can be omitted and the variable damper 7 can be controlled. In other words, when the first state quantity is abnormal, the variable damper 7 can be controlled based on the third state quantity. This makes it possible to continue controlling the variable damper 7 even when a sensor is abnormal, thereby maintaining ride comfort.

[0062] In this way, in this embodiment, calculations such as sprung and unsprung speeds required for suspension control are performed from the three sensor signals, and an abnormal sensor can be determined by a majority vote of the calculation results. Furthermore, when an abnormality is detected, suspension control using a more accurate sensor is performed, thereby maintaining ride comfort even during an abnormality. Furthermore, in this embodiment, in addition to the sensors used for suspension control (sprung acceleration sensor 9, unsprung acceleration sensor 10), sensors attached to the vehicle for other purposes (wheel speed sensor 13, IMU 11) are used, and comparable calculation results are obtained by calculations appropriate for each sensor, and a majority vote is then performed on these. This makes it possible to determine an abnormality and continue functioning thereafter while suppressing increases in cost and power consumption.

[0063] In the embodiment, the acceleration detection means is described as the sprung acceleration sensor 9 and the unsprung acceleration sensor 10, but the present invention is not limited to this. For example, the acceleration detection means may be a vehicle height sensor that detects the vehicle height, or a stroke sensor that detects the stroke length of the suspension device.

[0064] In the embodiment, second sprung / unsprung state quantity calculation unit 29 estimates the sprung speed and relative speed of each wheel as the second state quantity from the behavior information including the wheel speed of each wheel using AI, but the present invention is not limited to this. For example, the second sprung / unsprung state quantity calculation unit may calculate the sprung speed and relative speed of each wheel as the second state quantity from the behavior information including the wheel speed of each wheel based on a mathematical formula using a Kalman filter or the like.

[0065] In the embodiment, the third sprung / unsprung state quantity calculation unit 30 calculates the stroke speed of the suspension device 5 of each wheel based on the sprung acceleration and the damping force, but the present invention is not limited to this. The third sprung / unsprung state quantity calculation unit may calculate the stroke speed of the suspension device 5 of each wheel based on the sprung velocity and the damping force, or may calculate the stroke speed of the suspension device 5 of each wheel based on the sprung acceleration and the command current value of the variable damper.

[0066] In the embodiment, the third sprung / unsprung state quantity calculation unit 30 uses AI to estimate the sprung speed and relative speed of each wheel as the third state quantity from the detection value of the IMU 11, but the present invention is not limited to this. For example, the second sprung / unsprung state quantity calculation unit may calculate the sprung speed and relative speed of each wheel as the third state quantity from the detection value of the IMU 11 based on a mathematical formula using a Kalman filter or the like.

[0067] In the embodiment, the controller 21 acquires data (wheel speed data) from the wheel speed sensor 13 via the CAN 12, but the present invention is not limited to this. For example, the controller may acquire wheel speed data directly from the wheel speed sensor 13. That is, the controller 21 may acquire, for example, detected values ​​of various sensors directly from the various sensors. Furthermore, the controller 21 may acquire behavior information including wheel speed from another controller, etc.

[0068] In the embodiment, the case where the IMU 11 is installed outside the controller 21 and is received by the controller 21 and used for control is described. However, the present invention is not limited to this, and the IMU may be mounted inside the controller.

[0069] In the embodiment, an example has been described in which the force generating mechanism is a variable damper 7 made up of a semi-active damper. The present invention is not limited to this, and an active damper (either an electric actuator or a hydraulic actuator) may be used as the force generating mechanism. In the embodiment, an example has been described in which the force generating mechanism that generates an adjustable force between the vehicle body 2 side and the wheel 3 side is configured by a variable damper 7 made up of a damping force adjustable hydraulic shock absorber. The present invention is not limited to this, and for example, the force generating mechanism may be configured by an air suspension, a stabilizer (kinesus), an electromagnetic suspension, or the like, in addition to a hydraulic shock absorber.

[0070] In the embodiment, a control device for a suspension device used in a four-wheeled automobile has been described as an example, but the present invention is not limited to this and may be applied to, for example, two-wheeled and three-wheeled vehicles, as well as work vehicles, transport vehicles such as trucks and buses. [Explanation of symbols]

[0071] 1: vehicle, 2: vehicle body, 3: wheel, 5: suspension device, 7: variable damper (force generating mechanism), 8: variable damping force actuator, 9: sprung acceleration sensor (acceleration detection means), 10: unsprung acceleration sensor (acceleration detection means), 11: IMU (vehicle motion detection means), 12: CAN, 13: wheel speed sensor (wheel speed detection means), 20: vehicle behavior control device, 21: controller, 23: damper control unit, 28: first sprung / unsprung state quantity calculation unit (first state quantity calculation unit), 29: second sprung / unsprung state quantity calculation unit (second state quantity calculation unit), 30: third sprung / unsprung state quantity calculation unit (third state quantity calculation unit), 31: state quantity comparison and selection processing unit, 32: damping force control unit

Claims

[Claim 1] A vehicle behavior control device that controls a force generating mechanism that is provided between a body and a wheel of a vehicle and generates an adjustable force between the body and the wheel, acceleration detection means for detecting an acceleration physical quantity relating to the acceleration of the vehicle; a first state quantity calculation unit that calculates a first state quantity of a vehicle behavior from the acceleration physical quantity; a second state quantity calculation unit that calculates a second state quantity of a vehicle behavior from a detection value of the wheel speed detection means that detects the rotational speed of the wheel; a third state quantity calculation unit that calculates a third state quantity of a vehicle behavior from a detection value of a vehicle motion detection means that detects six-axis motion quantities of the vehicle; comparing the values ​​of the first state quantity, the second state quantity, and the third state quantity, and determining that there is an abnormality when the one value is outside a predetermined range with respect to at least two values; controlling the engine based on the first state quantity except when the first state quantity is abnormal; an abnormality determination unit that, when the first state quantity is abnormal, controls based on the third state quantity.

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