Vehicle control device and vehicle control method

Abstract

This vehicle control device (10) for a vehicle comprising left and right drive systems is provided with a calculation unit (13), a sum model, a difference model, a state calculation unit (14), and a control unit (15). The calculation unit (13) calculates: a sum-equivalent value corresponding to the sum of left and right required torques; and a difference-equivalent value corresponding to the difference between the left and right required torques. The sum model is obtained by modelling the movement states of the left and right drive systems when a vehicle (1) is moving straight ahead, and the sum-equivalent value is applied to the sum model. The difference model is obtained by modelling the movement states of the left and right drive systems when the vehicle (1) is turning, and the difference-equivalent value is applied to the difference model. The control unit (15) controls the output of a left drive source and a right drive source using a sum mode instruction torque and a difference mode instruction torque obtained through application to the sum model and the difference model, respectively. The state calculation unit (14) calculates a road surface state value. A load-side inertia that constitutes a transfer function included in each of the sum model and the difference model is calculated on the basis of the road surface state value.

Description

Vehicle control device and vehicle control method

[0001] The present invention relates to a vehicle control device and a vehicle control method for controlling a drive source mounted on a vehicle.

[0002] Conventionally, in a vehicle equipped with multiple drive sources, a method has been known in which a vehicle model that models the behavior of the drive force transmission system is used to control the operating state of each drive source while suppressing vibrations in the drive force transmission system (see Patent Document 1).

[0003] Japanese Patent Application Publication No. 2019-103249

[0004] The behavior (e.g., vibration) of the drivetrain differs between when the vehicle is traveling straight and when it is turning. Therefore, it is necessary to develop separate controls for when the vehicle is traveling straight and when it is turning, which can lead to a complex control configuration. Furthermore, the vehicle's driving state can be a complex state that combines a straight-line driving state (translational motion) and a turning state (yaw motion), making it difficult to improve controllability. For example, when performing control to suppress vibration on one of the left and right axles, the control (output) also affects the other axle. Therefore, decoupling is required to prevent mutual influence, which complicates the control configuration. In other words, it is difficult to appropriately suppress vibration on each of the left and right axles due to the different vibration characteristics when traveling straight and when turning. Furthermore, the behavior of the drivetrain differs not only depending on the driving state described above, but also on the road surface conditions on which the vehicle is traveling (e.g., when the vehicle is traveling on a low-μ road and when it is traveling on a high-μ road). For this reason, it is desirable to be able to appropriately suppress vibrations on each of the left and right axles, not only for vibration characteristics that differ when traveling straight and when turning, but also for vibration characteristics that differ depending on road surface conditions.

[0005] One of the objects of the present invention has been devised in light of the above-mentioned problems, and is to provide a vehicle control device and a vehicle control method that are simple in configuration and can suppress vibrations of the left and right axles without interfering with each other, in response to vibration characteristics that differ depending on road surface conditions in addition to vibration characteristics that differ between when traveling straight and when turning. In addition to this object, another object of the present invention is to achieve effects derived from the configurations shown in the "Mode for Carrying Out the Invention" described below, which are effects that cannot be obtained with conventional technology.

[0006] The disclosed invention can be realized as the following disclosed embodiments (application examples) and solves at least part of the above-mentioned problems. Each embodiment from embodiment 2 onwards is an embodiment that can be selected as an additional embodiment, and each embodiment can be omitted. None of the embodiments from embodiment 2 onwards discloses an embodiment or configuration that is essential to the present invention.

[0007] Aspect 1. The disclosed vehicle control device is a vehicle control device that controls the output of a left drive source and a right drive source in a vehicle that has a left drive system including a left axle and left wheels to which power from a left drive source is transmitted, and a right drive system including a right axle and right wheels to which power from a right drive source is transmitted. This vehicle control device includes a sum model that models the motion states of the left drive system and the right drive system when the vehicle is traveling straight, and a difference model that models the motion states of the left drive system and the right drive system when the vehicle is turning. This vehicle control device also includes a calculation unit, a state calculation unit, and a control unit.

[0008] The calculation unit calculates a sum equivalent value corresponding to the sum of a left required torque, which is a torque required for the left drive system or the left drive source, and a right required torque, which is a torque required for the right drive system or the right drive source, and calculates a difference equivalent value corresponding to the difference between the left required torque and the right required torque. The sum equivalent value is applied to the sum model, and the difference equivalent value is applied to the difference model. The condition calculation unit calculates a road surface condition value that represents the road surface condition of the vehicle.

[0009] The sum model and the difference model are both two-inertia system models. The sum model includes a transfer function representing input / output characteristics of the two-inertia system, which includes a drive-side inertia calculated based on the inertias of the left drive source and the right drive source, a spring damper designed with stiffness and viscosity, and a load-side inertia calculated based on the vehicle body weight and the road surface condition value. The difference model includes a transfer function representing input / output characteristics of the two-inertia system, which includes a drive-side inertia that is equivalent inertia when a torque difference occurs, which is calculated based on a torque difference amplification factor, a spring damper designed with stiffness and viscosity, and a load-side inertia calculated based on the yaw inertia of the vehicle and the road surface condition value.

[0010] The control unit controls the outputs of the left drive source and the right drive source using a sum mode command torque obtained by applying the sum equivalent value to the sum model and a difference mode command torque obtained by applying the difference equivalent value to the difference model.

[0011] Aspect 2. In an aspect including the above-described aspect 1, the road surface condition value is preferably calculated from the actual slip ratios of the left wheel and the right wheel. Aspect 3. In an aspect including the above-described aspect 1, the vehicle control device preferably includes a traction control unit that performs traction control to reduce the left requested torque and the right requested torque when slip of the vehicle is detected. In this case, the road surface condition value is preferably calculated based on the implementation state of the traction control by the traction control unit.

[0012] Aspect 4. The disclosed vehicle control method is a vehicle control method for controlling the outputs of a left drive source and a right drive source in a vehicle equipped with a left drive system including a left axle and left wheels to which power from a left drive source is transmitted, and a right drive system including a right axle and right wheels to which power from a right drive source is transmitted. First, a sum model that models the motion states of the left drive system and the right drive system when the vehicle is traveling straight, and a difference model that models the motion states of the left drive system and the right drive system when the vehicle is turning are prepared in advance.

[0013] The sum model and the difference model are both two-inertia system models. The sum model includes a transfer function representing input / output characteristics of a two-inertia system including a drive-side inertia calculated based on the inertias of the left drive source and the right drive source, a spring damper designed with stiffness and viscosity, and a load-side inertia calculated based on the vehicle body weight and a road surface condition value representing the road surface condition of the vehicle. The difference model includes a transfer function representing input / output characteristics of a two-inertia system including a drive-side inertia that is equivalent inertia when a left-right difference occurs, calculated based on a torque difference amplification factor, a spring damper designed with stiffness and viscosity, and a load-side inertia calculated based on the yaw inertia of the vehicle and the road surface condition value.

[0014] A sum equivalent value corresponding to the sum of a left required torque, which is a torque required for the left drive system or the left drive source, and a right required torque, which is a torque required for the right drive system or the right drive source, is calculated, and a difference equivalent value corresponding to the difference between the left required torque and the right required torque is calculated. The sum equivalent value is applied to the sum model to obtain a sum mode command torque, and the difference equivalent value is applied to the difference model to obtain a difference mode command torque. The outputs of the left drive source and the right drive source are controlled using the sum mode command torque and the difference mode command torque.

[0015] According to the disclosed vehicle control device and vehicle control method, left and right drive sources are controlled using a sum mode command torque obtained by applying a sum equivalent value to the sum model and a differential mode command torque obtained by applying a differential equivalent value to the differential model. In the sum model, the load-side inertia constituting the transfer function representing the input / output characteristics of the two-inertia system is calculated based on road surface condition values. In the differential model, the load-side inertia constituting the transfer function representing the input / output characteristics of the two-inertia system is also calculated based on road surface condition values. This allows vibrations of the left and right axles to be suppressed without interfering with each other, even when the vibration characteristics differ between straight-line driving and cornering and when the vibration characteristics differ depending on the road surface condition. Furthermore, since complex decoupling control is not required, vibration suppression can be achieved with a simple configuration.

[0016] 1 is a block diagram showing the configuration of a vehicle control device and a vehicle. FIG. 2 is a schematic diagram showing an example of the structure of a vehicle drive system. FIG. 3 is a speed diagram of a power distribution mechanism of a vehicle having the structure of FIG. 2. FIG. 4 is a block diagram showing the flow of a vehicle control method. FIG. 5 is a block diagram showing the logic of vibration suppression control implemented by the vehicle control device when a road surface condition value is calculated using a first method. FIG. 6 is a block diagram showing the logic of vibration suppression control implemented by the vehicle control device when a road surface condition value is calculated using a second method. FIG. 7 is a schematic diagram showing the structure of the left and right drive systems of a vehicle. (A) is a schematic diagram of a sum model, and (B) is a schematic diagram of a difference model. FIG. 8 is a table in which parameters are broken down into a sum mode and a difference mode in a derived transfer function formula as an example.

[0017] The types of vehicles in which the disclosed vehicle control device and vehicle control method can be used include, for example, engine vehicles (gasoline vehicles, diesel vehicles), electric vehicles, and hybrid vehicles, which run by driving left and right wheels (left and right drive wheels) using at least one drive source (internal combustion engine or motor), preferably a vehicle that runs by driving left and right wheels (left and right drive wheels) using multiple drive sources. Here, one of the multiple drive sources is referred to as the left drive source, and the other drive source is referred to as the right drive source. Also, of the left and right wheels, one located on the left side of the vehicle is referred to as the left wheel, and the other is referred to as the right wheel. The disclosed vehicle control device and vehicle control method can be used to control a vehicle that has a left drive system including a left axle and left wheels to which power is transmitted from the left drive source, and a right drive system including a right axle and right wheels to which power is transmitted from the right drive source.

[0018] The layout of each of the left and right drive sources may or may not correspond to the left-right direction defined based on the vehicle's direction of travel. Furthermore, the left and right drive systems may operate independently of each other, or may be connected to each other via a transmission mechanism or a power distribution mechanism. The disclosed vehicle control device and vehicle control method can be used to control in-wheel motor vehicles in which the left and right wheels are driven by individual motors, as well as torque vectoring vehicles in which the left and right wheels can transmit driving force or torque to each other.

[0019] [1. Configuration] A vehicle control device 10 according to an embodiment is mounted on a vehicle 1 shown in FIG. 1. The vehicle 1 includes left and right wheels 5 (wheels) arranged side by side in the vehicle width direction, a power distribution mechanism 3 (differential mechanism) that applies a torque difference to the left and right wheels 5, and a pair of motors 2 connected to the power distribution mechanism 3. In the drawings of the embodiment, the letters L and R added to the numeral symbols indicate the location of the element associated with the symbol (whether it is on the left or right side of the vehicle 1). For example, 5L indicates one of the left and right wheels 5 located on the left side of the vehicle 1 (the left wheel), and 5R indicates the other wheel located on the right side (the right wheel). The positions of the left and right wheels 5 in the fore-and-aft direction are not important, and they may be the front or rear wheels of the vehicle 1.

[0020] The motor 2 (drive source) has the function of driving at least either the front wheels or the rear wheels of the vehicle 1, and can also have the function of driving all four wheels. Of the pair of motors 2, one located on the left side is the left motor 2L (left drive source), and the other located on the right side is the right motor 2R (right drive source). The left motor 2L and the right motor 2R operate independently of each other and can individually output drive forces of different magnitudes. These motors 2 are connected to the power distribution mechanism 3 via a pair of speed reduction mechanisms provided separately from each other.

[0021] The vehicle 1 is equipped with a power distribution mechanism 3 that amplifies the torque difference between the pair of motors 2 and distributes it to each of the left and right wheels 5. The power distribution mechanism 3 in this embodiment is a differential mechanism with a yaw control function (AYC (Active Yaw Control) function) and is interposed between an axle 4 (left axle 4L) connected to the left wheel 5L and an axle 4 (right axle 4R) connected to the right wheel 5R. The yaw control function actively controls the ratio of the driving force (driving torque) shared between the left and right wheels 5 to adjust the yaw moment and stabilize the posture of the vehicle 1. The power distribution mechanism 3 incorporates a planetary gear mechanism, a differential gear mechanism, and the like. A vehicle drive system including the pair of motors 2 and the power distribution mechanism 3 is also called a DM-AYC (Dual Motor AYC) system.

[0022] As shown in Figure 2, the power distribution mechanism 3 includes a pair of speed reduction mechanisms (gear trains surrounded by dashed lines in Figure 2) and a transmission mechanism (gear trains surrounded by dashed lines in Figure 2) that reduce the rotational speed of the motor 2. The speed reduction mechanism is a mechanism that increases the torque (driving force) output from the motor 2 by reducing the torque. The reduction ratio G of the speed reduction mechanism is set appropriately depending on the output characteristics and performance of the motor 2. If the torque performance of the motor 2 is sufficiently high, the speed reduction mechanism may be omitted. The transmission mechanism is a mechanism that amplifies the difference in torque transmitted to each of the left and right wheels 5.

[0023] The transmission mechanism of the power distribution mechanism 3 shown in FIG. 2 includes a pair of planetary gear mechanisms. These planetary gear mechanisms have a structure in which the rotation axes of planetary gears provided on each carrier are connected to each other. Each carrier supports the planetary gear so that it can rotate and so that the planetary gear can revolve between a sun gear and a ring gear. Driving forces transmitted from the left and right motors 2 are input to the ring gear and sun gear of one planetary gear mechanism. Driving forces transmitted to the left and right wheels 5 are extracted from the sun gear and carrier of the other planetary gear mechanism. Note that the structure of the power distribution mechanism 3 shown in FIG. 2 is merely one example for achieving yaw control, and other known structures may also be used.

[0024] In addition, J in FIG. Ｍ is the motor inertia (moment of inertia of motor 2), D Ｍ is the motor viscosity (viscosity of motor 2), J ｗ represents the wheel inertia (moment of inertia of the left and right wheels 5). ＬＭ is the left motor input torque (left motor command torque), T Ｌｍ is the left motor input torque after deceleration by the reduction mechanism, ω ＬＭ is the left motor angular velocity, ω Ｌｍ is the angular velocity of the left motor after deceleration by the deceleration mechanism, T Ｌｉｎ is the torque on the left drive side, T Ｌｄｓ is the left axle torque, T ＬＬ is the left wheel load torque, ω Ｌｄｓ is the left driving side angular velocity, ω ＬＬ is the left wheel angular velocity. Similarly, for the parameters of the right drivetrain, T ＲＭ is the right motor input torque (right motor command torque), T Ｒｍ is the right motor input torque after deceleration by the reduction mechanism, ω ＲＭ is the right motor angular velocity, ω Ｒｍ is the angular velocity of the right motor after deceleration by the deceleration mechanism, T Ｒｉｎ is the right drive torque, T Ｒｄｓ is the right axle torque, T ＲＬ is the right wheel load torque, ω Ｒｄｓ is the right drive side angular velocity, ω ＲＬ is the right wheel angular velocity.

[0025] 3 is a velocity diagram of the power distribution mechanism 3. １ , b ２ represents the torque difference amplification factor (deceleration rate, differential reduction ratio) determined according to the structure of the gears built into the power distribution mechanism 3. The torque difference amplification factor related to the power transmission from the left motor 2L to the right wheel 5R is b １ The torque difference amplification factor for power transmission from the left motor 2L to the left wheel 5L is b １ +1. The torque difference amplification factor for power transmission from the right motor 2R to the left wheel 5L is b ２ The torque difference amplification factor for power transmission from the right motor 2R to the right wheel 5R is b ２ It's +1.

[0026] As shown in FIG. 1 , each of the pair of motors 2 is electrically connected to a battery 7 via an inverter 6 (6L, 6R). The inverter 6 is a converter (DC-AC inverter) that converts between power (DC power) from a DC circuit on the battery 7 side and power (AC power) from an AC circuit on the motor 2 side. The battery 7 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is a secondary battery that can supply high-voltage DC current of several hundred volts. When the motor 2 is powered, the DC power is converted into AC power by the inverter 6 and supplied to the motor 2. When the motor 2 is generating power, the generated power is converted into DC power by the inverter 6 and charged into the battery 7. The operating state of the inverter 6 is controlled by a vehicle control device 10.

[0027] The vehicle control device 10 is one of the electronic control units (ECU) mounted on the vehicle 1. The vehicle 1 is equipped with a left drivetrain including a left axle 4L and a left wheel 5L to which power is transmitted from a left motor 2L (left drive source), and a right drivetrain including a right axle 4R and a right wheel 5R to which power is transmitted from a right motor 2R (right drive source).The vehicle control device 10 has a function of controlling the output of each of the left motor 2L and the right motor 2R.

[0028] The vehicle control device 10 incorporates a processor (central processing unit), memory (main memory), storage device, interface device, etc. (not shown), which are communicably connected to one another via an internal bus. The contents of the determinations and controls performed by the vehicle control device 10 are recorded and saved in the memory as firmware or application programs, and when the programs are executed, the contents of the programs are expanded in the memory space and executed by the processor.

[0029] The vehicle control device 10 is connected to an accelerator opening sensor 21, a brake sensor 22, a steering angle sensor 23, a resolver 24, and a wheel speed sensor 25. The accelerator opening sensor 21 is a sensor that detects the amount of depression of the accelerator pedal (accelerator opening) and the depression speed. The brake sensor 22 is a sensor that detects the amount of depression of the brake pedal (brake pedal stroke) and the depression speed. The steering angle sensor 23 is a sensor that detects the steering angle of the left and right wheels 5 (actual steering angle or steering angle of the steering wheel).

[0030] The resolvers 24 (24L, 24R) are sensors that detect the angular velocity of the motors 2 and are individually provided for each of the pair of motors 2. The resolvers 24 output information on the rotation angle of the motors 2 as two-phase AC voltages. The angular velocity of the motors 2 is determined from changes in these AC voltages over time. The wheel speed sensors 25 (25L, 25R) are sensors that detect the angular velocity of the axles 4. The vehicle control device 10 controls the operating state of the inverters 6 (6L, 6R) based on the information detected by the various sensors 21 to 25, thereby controlling the output of the pair of motors 2 (2L, 2R). Note that instead of the resolvers 24, other sensors (such as hall sensors or encoders) with different internal structures or operating principles may be used.

[0031] 4 is a schematic block diagram showing the basic concept (flow) of control (output control for the motor 2 using the vehicle control method of the embodiment) implemented by the vehicle control device 10. In this control, vibrations in the left and right drivetrains are separated into vibrations when the vehicle 1 travels straight and vibrations when the vehicle 1 turns, with the former being classified as sum mode vibrations and the latter as difference mode vibrations. Torques for suppressing vibrations in the sum mode and difference mode are then obtained, and the obtained torques are converted back into left and right expressions before being output (commanded) to the left motor 2L and the right motor 2R.

[0032] The storage device of the vehicle control device 10 pre-stores a sum-mode vibration suppression model (hereinafter simply referred to as the "sum model") used in the sum mode and a difference-mode vibration suppression model (hereinafter simply referred to as the "difference model") used in the difference mode. That is, in this vehicle control method, a sum model and a difference model are first prepared. The sum model is a model that models the motion states of the left and right drive trains when the vehicle 1 is traveling straight, and the difference model is a model that models the motion states of the left and right drive trains when the vehicle 1 is turning. The sum model and the difference model are models related to vibration suppression.

[0033] Generally, the vehicle 1 generates different vibrations when traveling straight and when turning, and the resonant frequencies are also different. While this varies depending on the type of vehicle 1, for example, the resonant frequency when traveling straight is approximately 6 Hz, while the resonant frequency when turning is lower, e.g., approximately 2 Hz. In this way, in order to effectively suppress the different vibrations when the vehicle 1 is traveling straight (translational motion) and when turning (yaw motion), and to prevent the left and right vibration suppression controls (outputs) from interfering with each other, the vehicle is separated into the above two modes, and a model is provided for each mode. That is, the sum model and the difference model are models used to activate vibration suppression control in the straight traveling and turning states, respectively, for the different resonant frequencies when traveling straight and when turning.

[0034] As shown in FIG. 4 , the sum model is applied with a sum equivalent value to output (derive) a sum mode command torque for suppressing vibrations in the left and right drivetrains when the vehicle 1 travels straight. Similarly, the difference model is applied with a difference equivalent value to output (derive) a difference mode command torque for suppressing vibrations in the left and right drivetrains when the vehicle 1 turns. The sum equivalent value is a general term for values ​​equivalent to the sum of the left required torque, which is the torque required for the left drivetrain or the left motor 2L, and the right required torque, which is the torque required for the right drivetrain or the right motor 2R. The sum equivalent value includes not only the simple sum, but also a value obtained by multiplying the sum by a predetermined coefficient and half the sum (arithmetic mean value). The difference equivalent value is a general term for values ​​equivalent to the difference between the left required torque and the right required torque. The difference equivalent value is a general term for values ​​equivalent to the difference between the left required torque and the right required torque. The difference equivalent value is not only the simple difference, but also a value obtained by multiplying the difference by a predetermined coefficient. In this way, by converting the left required torque and the right required torque into sum and difference expressions (sum equivalent value and difference equivalent value) and applying them to the sum model and difference model, it becomes possible to apply vibration suppression control in both straight-ahead and cornering states.

[0035] As described above, the vibrations generated by the vehicle 1 differ when traveling straight and when turning. The vibrations also differ depending on the road surface condition of the vehicle 1 (when traveling on a high-μ road and when traveling on a low-μ road). Therefore, the resonance frequencies also differ when traveling on a high-μ road (hereinafter also referred to as "grip") and when traveling on a low-μ road (hereinafter also referred to as "slip"). While this differs depending on the type of vehicle 1, for example, when traveling straight, the resonance frequency when gripping is about 6 Hz, whereas the resonance frequency when slipping is higher, for example, about 9 Hz. Similarly, when turning, the resonance frequency when slipping is a different value from the resonance frequency when gripping (about 2 Hz, as described above).

[0036] Therefore, in the present disclosure, as shown in Fig. 4, road surface condition values ​​representing the road surface conditions of the vehicle 1 are applied to both the sum model and the difference model. The sum model outputs (derives) a sum mode command torque for suppressing vibrations in the left and right drivetrains when the vehicle 1 is traveling straight, in accordance with the applied road surface condition values. Similarly, the difference model outputs (derives) a difference mode command torque for suppressing vibrations in the left and right drivetrains when the vehicle 1 is turning, in accordance with the applied road surface condition values.

[0037] Step A1 in Fig. 4 corresponds to a step of calculating a sum equivalent value that corresponds to the sum of the left required torque and the right required torque. The sum equivalent value calculated in this step is applied to the sum model in step A3 in Fig. 4. Step A5 in Fig. 4 corresponds to a step of calculating a road surface condition value. The road surface condition value calculated in this step is applied to the sum model in step A3 in Fig. 4. As a result, outputs (sum mode command torques) for vibration suppression of the left drivetrain and right drivetrain when the vehicle 1 is traveling straight are obtained, taking into account the road surface condition, and the vibration state of the vehicle 1 associated with traveling straight is effectively suppressed.

[0038] Step A2 in Fig. 4 corresponds to a step of calculating a difference equivalent value corresponding to the difference between the left required torque and the right required torque. The difference equivalent value calculated in this step is applied to the difference model in step A4 in Fig. 4. As with the sum model, the road surface condition value calculated in step A5 is applied to the difference model. As a result, outputs (differential mode command torques) for vibration suppression of the left and right drivetrains when the vehicle 1 is turning are obtained, taking into account the road surface condition, and the vibration state of the vehicle 1 related to turning is effectively suppressed.

[0039] Next, a specific configuration for implementing the above control will be described. Fig. 5 is a block diagram showing an example of logic for vibration suppression control implemented by the vehicle control device 10. Fig. 6 is a block diagram showing another example of logic for vibration suppression control implemented by the vehicle control device 10. Fig. 5 shows a case where the road surface condition value is calculated by a first method described later, and Fig. 6 shows a case where the road surface condition value is calculated by a second method described later.

[0040] The vibration suppression control is a control for determining a sum mode command torque and a difference mode command torque based on a sum model and a difference model. The plant in Figures 5 and 6 refers to an object (such as the motor 2, the shafts and gears included in the power distribution mechanism 3) located upstream of each axle 4 in the power transmission path.

[0041] As shown in Figures 5 and 6, the vehicle control device 10 of the example and the vehicle control device 10 of the other example each include a left / right required torque calculation unit 11, a traction control unit 12, a sum / difference required torque calculation unit 13 (calculation unit), a state calculation unit 14, and a control unit 15. These elements are shown by conveniently classifying the functions of the vehicle control device 10. These elements may be written as independent programs for realizing the functions of each element. Alternatively, multiple elements may be combined and written as a single composite program.

[0042] The left / right required torque calculation unit 11 calculates the left required torque and the right required torque. Based on the driver's operation (e.g., accelerator operation, brake operation, steering operation, etc.), the left / right required torque calculation unit 11 calculates the required torque for the left drivetrain or the left motor 2L as the "left required torque" and calculates the required torque for the right drivetrain or the right motor 2R as the "right required torque." Note that the method for calculating these required torques is not particularly limited, and they may be calculated based on vehicle speed information, etc., in addition to the driver's operation.

[0043] The left required torque is, for example, the required torque T Ｌｄｓ－ｒｅｆ (Hereinafter, "left axle required torque T Ｌｄｓ－ｒｅｆ The right required torque is, for example, the required torque T Ｒｄｓ－ｒｅｆ (Hereinafter, “right axle required torque T Ｒｄｓ－ｒｅｆ In this embodiment, these axle required torques T Ｌｄｓ－ｒｅｆ , T Ｒｄｓ－ｒｅｆ are used as the left and right required torques.

[0044] The traction control unit 12 performs traction control to reduce the left and right required torques calculated by the left and right required torque calculation unit 11 when slippage of the vehicle 1 is detected. The reduction amounts of the left and right required torques reduced by traction control may be constants or may be variables set based on, for example, the left and right required torques, vehicle speed information, etc. When the traction control unit 12 cooperates with a braking system (not shown) of the vehicle 1 to suppress slippage of the vehicle 1 (to perform traction control), the reduction amounts may be set taking into account the braking forces applied to the left and right wheels 5. The left and right required torques reduced by the traction control unit 12 are transmitted to the sum / difference required torque calculation unit 13. When the traction control unit 12 does not detect slippage of the vehicle 1, it transmits the values ​​transmitted from the left and right required torque calculation unit 11 to the sum / difference required torque calculation unit 13 as is.

[0045] As shown in Fig. 6, the traction control unit 12 may be provided with a control flag X for identifying the implementation state of traction control. The control flag X is transmitted to the state calculation unit 14 when the road surface condition value is calculated by the second method described below. The control flag X has an initial value of 0 and is set to 1 while traction control is being implemented. In other words, when the control flag X has a value of 0, it indicates that the implementation state of traction control is "not being implemented," and when the control flag X has a value of 1, it indicates that the implementation state of traction control is "being implemented."

[0046] Known control conditions can be applied to the start and end conditions of traction control. For example, when the difference between the actual wheel speed and the target wheel speed exceeds a predetermined difference, it is determined that the wheels have started to slip, traction control is started, and a control flag X is set to 1. For example, when the difference between the actual wheel speed and the target wheel speed falls below a predetermined difference, it is determined that the wheels have stopped slipping, traction control is ended, and a control flag X is set to 0. Traction control is not limited to the difference between the actual wheel speed and the target wheel speed, but also applies to the actual slip ratio λ (described later). ＲThe start and end of the rotation may be determined based on the angular acceleration of the motor 2 calculated from the angular velocity of the motor 2 detected by the resolver 24, or the angular acceleration of the axle 4 calculated from the angular velocity of the axle 4 detected by the wheel speed sensor 25.

[0047] The sum / difference required torque calculation unit 13 calculates a sum equivalent value and a difference equivalent value. The sum / difference required torque calculation unit 13 calculates the sum equivalent value and the difference equivalent value based on the left required torque and the corresponding right required torque. As shown in Figures 5 and 6 , the sum / difference required torque calculation unit 13 of this embodiment calculates the sum equivalent value and the difference equivalent value based on the left required torque and the right required torque transmitted from the traction control unit 12.

[0048] In this embodiment, the sum mode required torque T Ｓｄｓ－ｒｅｆ is calculated, and the differential mode required torque T Ｄｄｓ－ｒｅｆ The following is an example of a case where the left axle required torque T Ｌｄｓ－ｒｅｆ and right axle required torque T Ｒｄｓ－ｒｅｆ The left axle required torque T Ｌｄｓ－ｒｅｆ and right axle required torque T Ｒｄｓ－ｒｅｆ The calculation formula is as follows:

[0049]

[0050] The state calculation unit 14 calculates a road surface state value that indicates the road surface state of the vehicle 1 (understands the road surface state of the vehicle 1). The state calculation unit 14 of this embodiment calculates a slip ratio λ as the road surface state value. The road surface state value is calculated, for example, by one of the following two methods. First method: actual slip ratio λ of the left wheel 5L and the right wheel 5R Ｒ Second method: Calculation based on the implementation status of traction control

[0051] (A) First Method The first method is to calculate the actual slip ratio λ of the left wheel 5L and the right wheel 5R. Ｒ In the first method, the state calculation unit 14 calculates the slip ratio λ as a road surface state value from, for example, the actual slip ratios λ of the left and right wheels 5. ＬＲ , λ ＲＲThe state calculation unit 14 calculates the actual slip ratio λ of the left and right wheels 5. ＬＲ , λ ＲＲ The sum mode actual slip ratio λ corresponds to the sum of ＳＲ and the actual slip ratio λ of the left and right wheels 5 ＬＲ , λ ＲＲ The difference mode actual slip ratio λ corresponds to the difference between ＤＲ Then, the calculated sum mode actual slip ratio λ ＳＲ Applying this to the sum model, the calculated difference mode actual slip ratio λ ＤＲ That is, in the first method, the state calculation unit 14 applies the actual slip ratio λ to the difference model. Ｒ Using the actual slip ratio λ Ｒ The sum mode actual slip ratio λ ＳＲ and the difference mode actual slip ratio λ ＤＲ and calculate.

[0052] Here, the yaw rate when the vehicle 1 turns is γ, the tread is d, and the right wheel reference wheel speed is V. ｒｒｘ , the left wheel reference wheel speed is V ｒｌｘ Then, the actual slip ratio of the right wheel λ ＲＲ and left wheel actual slip ratio λ ＬＲ is calculated, for example, by the following formula: ＲＲ is the actual wheel speed of the right wheel, for example, the angular velocity ω of the right wheel 5R ＲＬ and the radius r of the left and right wheels 5. ＬＲ is the actual left wheel speed, for example, the angular velocity ω of the left wheel 5L ＬＬ and the radius r of the left and right wheels 5. ｘ is the vehicle speed. The actual slip ratio of the right wheel λ ＲＲ and left wheel actual slip ratio λ ＬＲ In the calculation of the angular velocity ω of the left and right wheels 5 ＬＬ , ω ＲＬ Instead of or in addition to the angular velocity ω of the motor 2 ＬＭ , ω ＲＭ (Angular velocity of the motor 2 detected by the resolver 24) may be used.

[0053]

[0054] The state calculation unit 14 calculates the actual slip ratio λ of the left and right wheels 5. ＬＲ , λＲＲ The sum mode actual slip ratio λ corresponds to the sum of ＳＲ and the actual slip ratio λ of the left and right wheels 5 ＬＲ , λ ＲＲ The difference mode actual slip ratio λ corresponds to the difference between ＤＲ The actual slip ratio λ of the left wheel is calculated as follows: ＬＲ and right wheel actual slip ratio λ ＲＲ Half of the sum is the sum mode actual slip ratio λ ＳＲ The actual slip rate of the left wheel is λ ＬＲ and right wheel actual slip ratio λ ＲＲ Half of the difference is the difference mode actual slip ratio λ ＤＲ The calculation formula for this case is as follows:

[0055]

[0056] (B) Second Method The second method is a method of calculating the slip ratio λ as a road surface condition value based on the implementation status of traction control. In this embodiment, the state calculation unit 14 uses the control flag X of the traction control unit 12 to grasp the implementation status of traction control, and sets (calculates) the slip ratio λ in synchronization with the control flag X. Specifically, when the control flag X transmitted from the traction control unit 12 is 0 (i.e., when the control flag X indicates "not implemented"), the state calculation unit 14 sets the slip ratio λ to 0 (slip ratio: 0%). When the control flag X is 1 (i.e., when the control flag X indicates "implemented"), the state calculation unit 14 sets the slip ratio λ to 1 (slip ratio: 100%). In this way, in the second method, the slip ratio λ is switched between 0 and 1. Then, the state calculation unit 14 applies the set slip ratio λ to each of the sum model and the difference model.

[0057] The control unit 15 controls the outputs of the left motor 2L and the right motor 2R using a sum mode command torque obtained by applying the sum equivalent value to the sum model and a differential mode command torque obtained by applying the difference equivalent value to the differential model. As shown in FIGS. 5 and 6 , the control unit 15 is provided with a sum mode control unit 16, a differential mode control unit 17, and a left-right conversion unit 18. The sum mode control unit 16 is provided with (stores) a sum model, which is a model (particularly related to vibration suppression) that models the motion states of the left drive system and the right drive system when the vehicle 1 is traveling straight. The differential mode control unit 17 is provided with (stores) a differential model, which is a model (particularly related to vibration suppression) that models the motion states of the left drive system and the right drive system when the vehicle 1 is turning. Before describing the sum model and the differential model, a schematic structure of the left drive system and the right drive system of the vehicle 1 will be described.

[0058] 7 is a schematic diagram showing the structure of the left and right drive trains of the vehicle 1. Each of the left axle 4L and the right axle 4R has a spring (axle stiffness K ｓ ) and damper (axle viscous D ｓ ) can be considered as a structure in which the J in FIG. ＬＭ is the inertia of the power distribution mechanism 3 side (drive side) relative to the left axle 4L, J Ｌｗ is the inertia of the left wheel 5L (load side) relative to the left axle 4L, J ＲＭ is the inertia of the power distribution mechanism 3 side (drive side) relative to the right axle 4R, J Ｒｗ is the inertia of the right wheel 5R side (load side) relative to the right axle 4R. Also, in FIG. 7, the left driving side angular velocity ω Ｌｄｓ (left driving side angular acceleration), left wheel angular velocity ω ＬＬ (left wheel angular acceleration), right drive side angular velocity ω Ｒｄｓ (right drive side angular acceleration), right wheel angular velocity ω ＲＬ The differential value (right wheel angular acceleration) of

[0059] Based on the above schematic diagrams, the configuration of the sum model is modeled as shown in Fig. 8(A), and the configuration of the difference model is modeled as shown in Fig. 8(B). The sum model is applied to vibration suppression control for the axles 4 and the left and right wheels 5 related to the straight-line traveling of the vehicle 1, and the difference model is applied to vibration suppression control for the axles 4 and the left and right wheels 5 related to the turning of the vehicle 1.

[0060] In this embodiment, the sum model is given a characteristic that makes resonance less likely to occur when traveling straight (a characteristic that does not include a resonance frequency component when traveling straight), and the difference model is given a characteristic that makes resonance less likely to occur when turning (a characteristic that does not include a resonance frequency component when turning). Furthermore, the sum model and the difference model are each given a characteristic that makes resonance less likely to occur when gripping (a characteristic that does not include a resonance frequency component when gripping) and a characteristic that makes resonance less likely to occur when slipping (a characteristic that does not include a resonance frequency component when slipping). In this way, by controlling the resonance frequencies of the sum model and the difference model differently and variably controlling the resonance frequencies of the sum model and the difference model according to road surface condition values, vibration suppression is possible in all driving conditions and on all road surface conditions. Note that, although both the sum model and the difference model are two-inertia models in this embodiment, each may be configured as a multi-inertia model including three or more moments of inertia and spring dampers.

[0061] As shown in FIG. 8A, the sum model uses the driving inertia J ＳＭ and rigidity K ｓ and viscosity D ｓ The spring damper is designed with the load side inertia (sum mode wheel nominal inertia) J ＳＬ Drive side inertia J ＳＭ is the inertia J of the drive sources (left drive source and right drive source) Ｍ For example, J ＳＭ = G ２ J Ｍ In addition, the load inertia J ＳＬ is calculated based on the vehicle weight M (in terms of wheels) and the road surface condition value. That is, in the sum model, the slip ratio λ applied from the condition calculation unit 14 is calculated based on the load side inertia J ＳＬIn other words, in the sum model, the load inertia J ＳＬ The value of changes depending on the slip ratio λ (road surface condition value).

[0062] The load inertia J is as follows: ＳＬ As shown in FIG. 5, when the condition calculation unit 14 calculates the road surface condition value using the first method, the slip ratio λ in the calculation formula is the sum mode actual slip ratio λ ＳＲ 6, when the condition calculation unit 14 calculates the road surface condition value by the second method, 1 or 0 is substituted for the slip ratio λ in the calculation formula according to the value of the control flag X.

[0063]

[0064] In addition, the drive side inertia J ＳＭ and load inertia J ＳＬ In addition, the drive side viscosity D ＳＭ and load side viscosity D ＳＬ The driving side viscosity D ＳＭ is the viscosity D of the drive source (left drive source and right drive source) Ｍ For example, D ＳＭ = G ２ D Ｍ In addition, T in FIG. Ｓｉｎ is the sum mode drive torque, T Ｓｄｓ is the sum mode axle torque, T ＳＬ is the sum mode wheel load torque, ω Ｓｄｓ is the sum mode drive-side angular velocity. The sum model may be expressed by a relational expression including a transfer function that represents the input / output characteristics of the two-inertia system. The equation of motion related to the sum model is shown below.

[0065]

[0066] As shown in FIG. 8B, the difference model uses the driving side inertia J ＤＭ and rigidity K ｓ and viscosity D ｓ The spring damper is designed with the load side inertia (differential mode wheel nominal inertia) J ＤＬ Drive side inertia J ＤＭis the inertia J of the drive sources (left drive source and right drive source) Ｍ and the torque difference amplification factor (b １ , b ２ etc.), for example, J ＤＭ = (2b １ +1) ２ G ２ J Ｍ In addition, the load inertia J ＤＬ is the yaw inertia I of vehicle 1 ｚ In other words, in the difference model, as in the sum model, the slip ratio λ applied from the state calculation unit 14 is calculated based on the load inertia J ＤＬ In other words, in the differential model, the load inertia J ＤＬ The value of varies depending on the slip ratio λ (road surface condition value).

[0067] The load inertia J is as follows: ＤＬ As shown in FIG. 5, when the condition calculation unit 14 calculates the road surface condition value using the first method, the slip ratio λ in the calculation formula is the difference mode actual slip ratio λ ＤＲ 6, when the condition calculation unit 14 calculates the road surface condition value by the second method, 1 or 0 is substituted for the slip ratio λ in the calculation formula according to the value of the control flag X.

[0068]

[0069] In addition, the drive side inertia J ＤＭ and load inertia J ＤＬ In addition, the drive side viscosity D ＤＭ and load side viscosity D ＤＬ The driving side viscosity D ＤＭ is the viscosity D of the drive source (left drive source and right drive source) Ｍ and torque difference amplification factor (b １ , b ２ etc.), for example, D ＤＭ = (2b １ +1) ２ G ２ D Ｍ In addition, T in FIG. Ｄｉｎ is the differential mode driving torque, T Ｄｄｓis the differential mode axle torque, T ＤＬ is the differential mode wheel load side torque, ω Ｄｄｓ is the differential mode driving side angular velocity. The differential model may also be expressed by a relational expression including a transfer function that represents the input / output characteristics of the two-inertia system. The equation of motion related to the differential model is shown below.

[0070]

[0071] The sum mode control unit 16 applies the sum equivalent value calculated by the sum / difference required torque calculation unit 13 to the sum model to obtain a sum mode command torque for suppressing vibrations in the left and right drive trains when the vehicle 1 travels straight. Here, as a specific example of the sum mode command torque, the sum mode drive-side torque T Ｓｉｎ As shown in FIGS. 5 and 6, the required torques for the left and right axles T Ｌｄｓ－ｒｅｆ , T Ｒｄｓ－ｒｅｆ (Right and left required torque) Ｓｄｓ－ｒｅｆ (sum equivalent value) is applied to the sum model, resulting in the sum mode command torque T Ｓｉｎ is obtained.

[0072] Similarly, the differential mode control unit 17 applies the difference equivalent value calculated by the sum / difference required torque calculation unit 13 to the above-mentioned differential model to obtain a differential mode command torque for suppressing vibrations in the left and right drive trains when the vehicle 1 turns. Here, as a specific example of the differential mode command torque, the differential mode drive-side torque T Ｄｉｎ As shown in FIGS. 5 and 6, the required torques for the left and right axles T Ｌｄｓ－ｒｅｆ , T Ｒｄｓ－ｒｅｆ (Right and left required torque) Ｄｄｓ－ｒｅｆ (difference equivalent value) is applied to the difference model, resulting in a difference mode indicated torque T Ｄｉｎ is obtained.

[0073] The left-right conversion unit 18 controls the outputs of the left motor 2L and the right motor 2R using the acquired sum mode command torque and difference mode command torque. Specifically, the left-right conversion unit 18 converts the sum mode command torque T Ｓｉｎ and differential mode torque T ＤｉｎBased on this, the torque to be output by each of the pair of motors 2 is calculated as the left motor command torque T ＬＭ and right motor command torque T ＲＭ and drives the pair of inverters 6 so as to obtain the torque. The left-right conversion unit 18 calculates the sum mode command torque T Ｓｉｎ Differential mode torque T Ｄｉｎ Half of the value obtained by subtracting ＬＭ and the sum mode command torque T Ｓｉｎ and differential mode torque T Ｄｉｎ Half of the sum of the right motor command torque T ＲＭ Output as

[0074] As a result, the actual left and right axle torques are calculated as the axle demand torque T Ｌｄｓ－ｒｅｆ , T Ｒｄｓ－ｒｅｆ , the controllability of the axle torque (driving torque) is improved, and vibration of the axle 4 (and therefore vibration of the vehicle 1) is effectively suppressed. In addition, since the sum model and the difference model are provided independently, the sum mode command torque T Ｓｉｎ and differential mode torque T Ｄｉｎ It is easy to impart different characteristics (vibration characteristics that differ when traveling straight and when turning, and vibration characteristics that differ depending on the road surface conditions when traveling straight and when turning).

[0075] The sum model of this embodiment is a sum mode drive side torque T Ｓｉｎ Similarly, the differential model of this embodiment includes a transfer function expressed as a ratio of the differential mode driving torque T Ｄｉｎ The transfer functions include a transfer function expressed as a ratio of the above. Using such transfer functions, it is possible to calculate a command torque that will result in a requested output. Below, an example of transfer functions of the sum model and the difference model that can be set in the vehicle 1 equipped with the power distribution mechanism 3 will be described.

[0076] 3. Specific Examples of Sum Model and Difference Model With regard to the derivation of the sum model and difference model described above, the power distribution mechanism 3 may be expressed mathematically as follows using vector representation.

[0077] Using the above formula, the equations of motion (sum and difference) for the driving side are formulated for the left and right sides respectively, as follows. １１ is the reduction ratio applied from the left drive source (left motor 2L) to the left axle (left axle 4L), Z ２２ is the reduction ratio applied from the right drive source (right motor 2R) to the right axle (right axle 4R), Z ｃ is the reduction ratio applied to the shafts on the opposite sides from the left and right drive sources.

[0078] Applying the matrix for converting to sum / difference mode to both sides of the above equation gives the following equation:

[0079] Here, b １ = b ２ If = b, then Z １１ -Z ｃ =Z ２２ -Z ｃ = |Z|, Z １１ +Z ｃ =Z ２２ +Z ｃ = 1, the formula can be transformed as follows to obtain the equations of motion for motor 2 corresponding to the sum and difference modes. In this way, by decomposing the equations of motion on the drive side into the sum and difference modes, the two are decoupled.

[0080]

[0081] Similarly to the derivation of the equation of motion on the drive side, the equation of motion for the left and right wheels 5 (load side) and the axle 4 may be expressed mathematically as follows:

[0082] Here, the dynamics of the left and right wheels 5 (load side) is P Ｌ Therefore, the equation of motion for the left and right wheels 5 (load side) in the above equation 12 can be rewritten as follows:

[0083] In addition, if disturbances are not taken into consideration in the process of applying the sum equivalent value to the sum model (i.e., the process of the sum mode control unit 16) and the process of applying the difference equivalent value to the difference model (i.e., the process of the difference mode control unit 17), the sum mode wheel load side torque T ＳＬ = 0, differential mode wheel load side torque T ＤＬ = 0, resulting in the following equation 14.

[0084] The dynamics of the driving side is expressed as P in the above equation 8. Ｍ Therefore, the equation of motion on the driving side of the above equation (11) can be rewritten as follows:

[0085] Furthermore, the dynamics of the axle 4 is expressed as P ＤＳ Therefore, the equation of motion for the axle 4 in the above equation (12) can be rewritten as follows:

[0086] ω in the above equation (16) Ｓｄｓ , ω Ｄｄｓ , ω ＳＬ , ω ＤＬ Substituting Equation 14 and Equation 15 into ＳＭ = G ２ J Ｍ , D ＳＭ = G ２ D Ｍ , J ＤＭ = (2b １ +1) ２ G ２ J Ｍ , D ＤＭ = (2b １ +1) ２ G ２ D Ｍ The sum mode driving torque T Ｓｉｎ , differential mode drive side torque T Ｄｉｎ When applied, the sum mode axle torque T Ｓｄｓ , differential mode axle torque T Ｄｄｓ is obtained.

[0087]

[0088] The transfer function of the above equation (17) is inversely expressed, and the required torque calculated by the upper ECU is expressed as T Ｓｄｓ－ｒｅｆ , T Ｄｄｓ－ｒｅｆ As a result, the axle torque T Ｓｄｓ , T Ｄｄｓ These required torques T Ｓｄｓ－ｒｅｆ , T Ｄｄｓ－ｒｅｆ Substituting, we get the following formula:

[0089]

[0090] Since the above equation (18) is not a proper transfer function, it is converted into a proper function using a second-order low-pass filter, and the following equation is obtained. This results in the requested sum / difference mode axle torque T Ｓｄｓ－ｒｅｆ , T Ｄｄｓ－ｒｅｆ In order to achieve this, the torque to be applied to the motor 2 (i.e., the sum mode command torque T Ｓｉｎ and differential mode indicated torque T Ｄｉｎ That is, the following equation 19 is an example of a transfer function included in the sum model and the difference model.

[0091]

[0092] Furthermore, when the parameters of the sum model and the difference model are decomposed using the derived transfer function formula, as shown in FIG. 9, there are parameters that appear only in the sum model (vehicle weight M) and parameters that appear only in the difference model (yaw inertia I ｚ ) and these parameters M, I ｚ are parameters that do not interfere with each other in the sum model and the difference model, and are hereinafter referred to as "non-interacting parameters".

[0093] In the vehicle control device 10 of this embodiment, in the adaptation process of the vehicle 1, the non-interference parameters M and I ｚ is used as an adjustment coefficient. In other words, in the sum model focusing on the straight-line state (translational motion) of the vehicle 1, the vehicle weight M as a non-interference parameter is adjusted and adapted so that the turning state is not affected. Similarly, in the difference model focusing on the turning state (yaw motion) of the vehicle 1, the yaw inertia I as a non-interference parameter is adjusted and adapted. ｚ By adjusting and adapting it, it does not affect straight-line driving.

[0094] [4. Effects] (1) The vehicle control device 10 described above includes a sum / difference required torque calculation unit 13, a sum model, a difference model, a state calculation unit 14, and a control unit 15. The sum / difference required torque calculation unit 13 calculates a sum equivalent value that corresponds to the sum of the left required torque and the right required torque, and calculates a difference equivalent value that corresponds to the difference between the left required torque and the right required torque. The sum model models the motion states of the left drive system and the right drive system when the vehicle 1 travels straight, and the sum equivalent value is applied. The difference model models the motion states of the left drive system and the right drive system when the vehicle 1 turns, and the difference equivalent value is applied.

[0095] The state calculation unit 14 calculates road surface state values ​​that represent the road surface state of the vehicle 1, and applies the calculated road surface state values ​​to both the sum model and the difference model. As a result, in the sum model, the load inertia that constitutes the transfer function that represents the input / output characteristics of the two-inertia system is calculated based on the applied road surface state values. Similarly, in the difference model, the load inertia that constitutes the transfer function that represents the input / output characteristics of the two-inertia system is calculated based on the applied road surface state values.

[0096] The control unit 15 then controls the left and right motors 2 using a sum mode command torque obtained by applying a sum equivalent value to the sum model and a difference mode command torque obtained by applying a difference equivalent value to the difference model. With this configuration, vibrations of the left and right axles 4 can be suppressed without interfering with each other despite the different vibration characteristics when traveling straight and when turning, and vibrations of the left and right axles 4 can be suppressed without interfering with each other despite the different vibration characteristics depending on the road surface condition in each driving state (when gripping and when slipping). Furthermore, by separating the sum model corresponding to the straight traveling state and the difference model corresponding to the turning state and constructing them as independent models, complex decoupling control is not required, allowing for a simpler design and vibration suppression with a simple configuration.

[0097] (2) The state calculation unit 14 calculates the actual slip ratio λ of the left wheel 5L and the right wheel 5R. Ｒ When calculating the road surface condition value from the sum model and the difference model, the load side inertia values ​​constituting the sum model and the difference model are calculated based on the actual slip ratio λ ＲTherefore, it is possible to realize precise vibration suppression control for vibration characteristics that vary depending on road surface conditions.

[0098] (3) When the condition calculation unit 14 calculates the road surface condition value based on the implementation state of traction control, the road surface condition value is binarized. Therefore, vibration suppression can be achieved with a simple configuration for vibration characteristics that vary depending on the road surface condition.

[0099] Additionally, in the above-described embodiment, both the sum model and the difference model can be constructed as two-inertia system models. This simple configuration allows for the construction of models relating to the motion states (particularly vibration suppression) of the left and right drivetrains when the vehicle 1 is traveling straight and when turning. Furthermore, it becomes possible to perform control that takes into account viscoelasticity for the different vibration characteristics of traveling straight and turning. This improves the controllability of the vehicle 1, resulting in a higher vibration suppression effect.

[0100] 8A, the sum model can be expressed by a transfer function that represents the input / output characteristics of a two-inertia system that includes a drive-side inertia calculated based on the inertias of the left and right drive sources, a spring damper designed in terms of stiffness and viscosity, and a load-side inertia calculated based on the vehicle weight and road surface condition values ​​of the vehicle 1. This makes it possible to effectively suppress vibrations during straight-line driving that take viscoelasticity into account, thereby improving the controllability of the vehicle 1.

[0101] 8(B), the above-mentioned difference model can be expressed by a transfer function that represents the input / output characteristics of a two-inertia system that is composed of a drive-side inertia, which is the equivalent inertia when a left-right difference occurs and is calculated based on the torque difference amplification factor, a spring damper designed in terms of stiffness and viscosity, and a load-side inertia that is calculated based on the yaw inertia and road surface condition values ​​of the vehicle 1. This makes it possible to effectively suppress vibrations during cornering that take viscoelasticity into account, thereby improving the controllability of the vehicle 1.

[0102] In addition, in the above-described vehicle control device 10, in the adaptation process, the non-interference parameters M and I ｚ is used as the adjustment coefficient, the adaptation in the straight running state and the adaptation in the turning state can be performed efficiently without interfering with each other.

[0103] [5. Other] The above-described embodiments are merely illustrative and are not intended to exclude various modifications or applications of techniques not explicitly described in the present embodiments. Each configuration of the present embodiments can be modified in various ways without departing from the spirit of the present embodiments. Furthermore, each configuration of the present embodiments can be selected or combined as needed.

[0104] For example, in the vehicle control device 10 described above, the control unit 15 may take into consideration a driver request of the vehicle 1 or the acceleration state of the vehicle 1 when controlling the outputs of the left motor 2L and the right motor 2R. Examples of the driver request include a steering wheel angle and an accelerator operation. Examples of the acceleration state include longitudinal acceleration (longitudinal G) and lateral acceleration (lateral G). The control unit 15 may take into consideration either the driver request or the acceleration state, or both. For example, the control unit 15 can perform control that takes these into consideration by inputting parameters of the driver request (e.g., steering wheel angle) and the acceleration state (longitudinal G, lateral G) into transfer function formulas included in the sum model and the difference model.

[0105] In the above embodiment, the left axle required torque T Ｌｄｓ－ｒｅｆ is used, and the right axle required torque T Ｒｄｓ－ｒｅｆ However, the torque required for the left motor 2L may be used as the left required torque, and the torque required for the right motor 2R may be used as the right required torque.

[0106] In the above embodiment, the case where the left required torque and the right required torque are calculated by the left and right required torque calculation unit 11 has been exemplified, but the left required torque and the right required torque may be calculated by calculation means other than the left and right required torque calculation unit 11, or may be calculated by an electronic control unit other than the vehicle control unit 10 (for example, a host ECU of the vehicle control unit 10). When the left required torque and the right required torque are calculated by an electronic control unit other than the vehicle control unit 10, the left and right required torque calculation unit 11 may be omitted.

[0107] In the above embodiment, the vehicle control device 10 is illustrated as including the traction control unit 12, but the vehicle control device 10 does not have to include the traction control unit 12. For example, when the road surface condition value is calculated using the first method of the above embodiment, the traction control unit 12 may be omitted.

[0108] In the above embodiment, the slip ratio λ is calculated as the road surface condition value, but the parameters calculated as the road surface condition value are not limited to this. The condition calculation unit 14 may calculate, for example, road surface friction, angular acceleration of the motor 2, angular acceleration of the axle 4, etc. as the road surface condition value, or may calculate a value based on two or more of these parameters as the road surface condition value.

[0109] In the above embodiment, the vehicle 1 is illustrated as being equipped with a pair of motors 2 as a drive source, but an internal combustion engine may be used instead of the motors 2, and the specific type of drive source is not important. Furthermore, the vehicle 1 is illustrated as being equipped with a vehicle drive system (DM-AYC system) including a pair of motors 2 and a power distribution mechanism 3, but the concepts of the sum model and the difference model are applicable to any vehicle, including vehicles that do not have a power distribution mechanism 3 and in-wheel motor vehicles. Control similar to that of the above embodiment can be implemented, and the same actions and effects as those of the above embodiment can be achieved, as long as the vehicle is equipped with at least a left drive system including a left axle and left wheels to which power from a left drive source is transmitted, and a right drive system including a right axle and right wheels to which power from a right drive source is transmitted.

[0110] The present invention is applicable to the vehicle control device manufacturing industry, and also to the vehicle manufacturing industry that mounts the vehicle control device.

[0111] REFERENCE SIGNS LIST 1 vehicle 2 motor (driving source) 3 power distribution mechanism 4 axle 5 left and right wheels 6 inverter 7 battery 10 vehicle control device 11 left and right required torque calculation unit 12 traction control unit 13 sum and difference required torque calculation unit (calculation unit) 14 state calculation unit 15 control unit 16 sum mode control unit 17 difference mode control unit 18 left and right conversion unit 21 accelerator opening sensor 22 brake sensor 23 steering angle sensor 24 resolver 25 wheel speed sensor

Claims

1. A vehicle control device for controlling outputs of a left driving source and a right driving source in a vehicle equipped with a left driving system including a left axle and left wheels to which power from a left driving source is transmitted, and a right driving system including a right axle and right wheels to which power from a right driving source is transmitted, comprising: a calculation unit that calculates a sum equivalent value equivalent to the sum of a left required torque, which is a required torque for the left driving source or the left driving source, and a right required torque, which is a required torque for the right driving system or the right driving source, and calculates a difference equivalent value equivalent to the difference between the left required torque and the right required torque; a state calculation unit that calculates a road surface state value that represents the road surface state of the vehicle; a sum model that models the motion state of the left driving system and the right driving system when the vehicle is traveling straight, and to which the sum equivalent value is applied; and a difference model that models the motion state of the left driving system and the right driving system when the vehicle is turning, and to which the difference equivalent value is applied. a control unit that controls outputs of the left drive source and the right drive source using a sum mode command torque obtained by applying the sum equivalent value to the sum model and a difference mode command torque obtained by applying the difference equivalent value to the difference model, wherein the sum model and the difference model are both two-inertia system models, the sum model includes a transfer function that represents input / output characteristics of the two-inertia system composed of a drive side inertia calculated based on the inertias of the left drive source and the right drive source, a spring damper designed with rigidity and viscosity, and a load side inertia calculated based on a body weight of the vehicle and the road surface condition value, and the difference model includes a transfer function that represents input / output characteristics of the two-inertia system composed of a drive side inertia that is an equivalent inertia when a left / right difference occurs, calculated based on a torque difference amplification rate, a spring damper designed with rigidity and viscosity, and a load side inertia calculated based on the yaw inertia of the vehicle and the road surface condition value.

2. The vehicle control device according to claim 1, wherein the road surface condition value is calculated from the actual slip ratios of the left and right wheels.

3. A vehicle control device as described in claim 1, further comprising a traction control unit that performs traction control to reduce the left required torque and the right required torque when slippage of the vehicle is detected, and the road surface condition value is calculated based on the implementation state of the traction control by the traction control unit.

4. A vehicle control method for controlling the output of a left driving source and a right driving source in a vehicle equipped with a left driving system including a left axle and left wheel to which power from a left driving source is transmitted, and a right driving system including a right axle and right wheel to which power from a right driving source is transmitted, comprising the steps of: preparing in advance a sum model that models the motion states of the left driving system and the right driving system when the vehicle is traveling straight, and a difference model that models the motion states of the left driving system and the right driving system when the vehicle is turning; both the sum model and the difference model are two-inertia system models; and the sum model includes a transfer function that represents the input / output characteristics of the two-inertia system composed of a drive side inertia calculated based on the inertia of the left driving source and the right driving source, a spring damper designed with rigidity and viscosity, and a load side inertia calculated based on a road surface condition value that represents the vehicle body weight and the road surface condition of the vehicle; the difference model includes a transfer function representing input / output characteristics of a two-inertia system composed of a drive-side inertia, which is an equivalent inertia when a left-right difference occurs, calculated based on a torque difference amplification rate, a spring damper designed with rigidity and viscosity, and a load-side inertia, which is calculated based on the yaw inertia of the vehicle and the road surface condition value; the vehicle control method comprises: calculating a sum equivalent value corresponding to the sum of a left required torque, which is a torque required to the left drive system or the left drive source, and a right required torque, which is a torque required to the right drive system or the right drive source, and calculating a difference equivalent value corresponding to the difference between the left required torque and the right required torque; obtaining a sum mode command torque by applying the sum equivalent value to the sum model, and obtaining a difference mode command torque by applying the difference equivalent value to the difference model; and controlling the outputs of the left drive source and the right drive source using the sum mode command torque and the difference mode command torque.

Images