Vehicle control device and vehicle control method

Abstract

A vehicle control device (10) of the present disclosure performs feedback control for reducing a difference between an actual wheel speed and a target wheel speed, by using a plant model which is composed of: a drive-side inertia (JLM, JRM) calculated on the basis of an inertia (JM) of a motor (2), which is a drive source of a vehicle (1); a spring damper designed with a rigidity (KS) and a viscosity (DS); and a load-side inertia (JLW, JRW) having a magnitude corresponding to a vehicle body weight (M). The vehicle control device (10) is provided with: a calculation unit (21) that calculates the load-side inertia (JLW, JRW) on the basis of motor torque and motor angular velocity or wheel speed; and a setting unit (22) that sets a correction value (Ki) for the feedback control according to the load-side inertia (JLW, JRW).

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 the driving force of a vehicle.

[0002] Conventionally, a vehicle control device that controls the driving force of a vehicle is known to perform feedback control so as to reduce the difference between the actual wheel speed and the target wheel speed. In the feedback control, for example, when the difference between the actual wheel speed and the target wheel speed becomes large, it is determined that the vehicle has entered a road surface with a low friction coefficient (low μ road), and the driving torque is reduced. This type of control effectively reduces the occurrence of slippage even when the friction coefficient of the road surface changes (see Patent Document 1).

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

[0004] On the other hand, when the vehicle enters a road surface with a high friction coefficient (high μ road), the difference between the actual wheel speed and the target wheel speed does not become large, just as when the vehicle continues to travel on a road surface with a low friction coefficient without slipping. Therefore, it takes time for the suppression of the drive torque to be released, which makes it difficult to achieve good responsiveness.

[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 can improve the responsiveness of feedback control. However, 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 technologies.

[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 performs feedback control to reduce the difference between an actual wheel speed and a target wheel speed using a plant model consisting of a drive-side inertia calculated based on the inertia of a motor that is a drive source of the vehicle, a spring damper designed with stiffness and viscosity, and a load-side inertia of a size corresponding to the vehicle body weight. This vehicle control device includes a calculation unit that calculates the load-side inertia based on motor torque and motor angular velocity or wheel speed, and a setting unit that sets a correction value for the feedback control according to the load-side inertia.

[0008] Aspect 2. In an aspect including the above-mentioned Aspect 1, it is preferable that the setting unit increases the integral correction value as the load-side inertia increases. Aspect 3. In an aspect including the above-mentioned Aspect 1, it is preferable that the calculation unit calculates the load-side inertia based on the motor torque, the motor angular velocity, and the wheel speed. Aspect 4. In an aspect including the above-mentioned Aspect 1, it is preferable that the vehicle includes a slip calculation unit that calculates a slip state of the vehicle, and the setting unit sets the integral correction value according to the slip state.

[0009] Aspect 5. In aspects including the above-mentioned Aspect 1, it is preferable that the setting unit calculates an apparent weight of the wheel and drive train corresponding to the load-side inertia, and sets an integral correction value having a magnitude corresponding to the apparent weight. Aspect 6. In aspects including the above-mentioned Aspect 4, it is preferable that the setting unit sets an integral correction value having a magnitude proportional to the apparent weight when the apparent weight is within a range equal to or less than a predetermined value.

[0010] Aspect 7. The disclosed vehicle control method performs feedback control to reduce the difference between an actual wheel speed and a target wheel speed using a plant model including a drive-side inertia calculated based on the inertia of a motor that is a drive source of the vehicle, a spring damper designed with stiffness and viscosity, and a load-side inertia of a size corresponding to the vehicle body weight. This vehicle control method calculates the load-side inertia based on motor torque, motor angular velocity, and wheel speed, and sets a correction value for the feedback control according to the load-side inertia.

[0011] According to the disclosed vehicle control device and vehicle control method, the load side inertia is calculated based on the motor torque and the motor angular velocity or the wheel speed, and a correction value for the feedback control is set in accordance with this load side inertia, thereby improving the responsiveness of the feedback control.

[0012] 1 is a block diagram of a vehicle to which a vehicle control device is applied. FIG. 2 is a schematic diagram showing an example of the structure of a vehicle drive system. FIG. 3 is a velocity diagram of a power distribution mechanism of a vehicle having the structure of FIG. 2. FIG. 4 is a schematic diagram showing the configurations of the left and right drive systems of a vehicle. (A) is a schematic diagram for explaining a left drive system plant model, and (B) is a schematic diagram for explaining a right drive system plant model. FIG. 5 is a block diagram showing functions (specific examples of control) of the calculation unit and control unit of FIG. 1. FIG. 6 is a graph showing the relationship between apparent weight and integral correction value.

[0013] The types of vehicles in which the disclosed vehicle control device and vehicle control method are used include, for example, engine vehicles (gasoline vehicles, diesel vehicles), electric vehicles, and hybrid vehicles. The disclosed invention relates to a vehicle equipped with a mechanism capable of adjusting the driving force of at least the left and right wheels (in other words, the left and right wheels, i.e., the left and right drive wheels), and the type and number of drive sources (internal combustion engine, motor, etc.) are not important.

[0014] The disclosed invention is preferably applied to an automobile 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. Furthermore, 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 wheel to which power is transmitted from the left drive source, and a right drive system including a right axle and right wheel to which power is transmitted from the right drive source.

[0015] 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.

[0016] [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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 planetary gears provided on respective carriers and their rotation axes are connected to each other. Each carrier supports a planetary gear so that it can rotate and also supports the planetary gear so that it revolves around a sun gear. Furthermore, 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 a yaw control function, and other known structures may also be used.

[0021] J in Figure 2 Ｍis the motor inertia (moment of inertia of motor 2), J Ｌｔ is the left wheel inertia (moment of inertia of the left wheel 5L), J Ｒｔ represents the right wheel inertia (moment of inertia of the right wheel 5R). 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 ＬＷ is the left wheel angular velocity (target velocity of the left wheel 5L). Similarly, for the parameters of the right drive system, 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 ＲＷ is the right wheel angular velocity (target velocity of the right wheel 5R).

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] The vehicle control device 10 is connected to an accelerator opening sensor 14, a brake sensor 15, a steering angle sensor 16, a resolver 17, and a wheel speed sensor 18. The accelerator opening sensor 14 is a sensor that detects the amount of depression of the accelerator pedal (accelerator opening) and the depression speed. The brake sensor 15 is a sensor that detects the amount of depression of the brake pedal (brake pedal stroke) and the depression speed. The steering angle sensor 16 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).

[0027] The resolvers 17 (17L, 17R) are sensors that detect the speed of the motors 2 and are individually provided for each of the pair of motors 2. The resolvers 17 output information on the rotation angle of the motors 2 as two-phase AC voltages. The speed of the motors 2 is determined from changes in these AC voltages over time. The wheel speed sensors 18 (18L, 18R) are sensors that detect the speed 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 14 to 18, thereby controlling the output of the pair of motors 2 (2L, 2R). Note that instead of the resolvers 17, other sensors (such as hall sensors or encoders) with different internal structures or operating principles may be used.

[0028] 1, the vehicle control device 10 includes a plant model, a correction value calculation unit 11, and a control unit 12 as elements for controlling the driving forces of the left and right drive trains. The control unit 12 has at least an FB control unit 13 related to feedback control. 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.

[0029] The plant model is a model of each of the left and right drivetrains of the vehicle 1 (power transmission path from the left motor 2L to the left wheel 5L) and the right drivetrain (power transmission path from the right motor 2R to the right wheel 5R) in order to grasp the motion states of these drivetrains. As shown in FIG. 4 , this plant model includes a left drivetrain plant model that models the left drivetrain and a right drivetrain plant model that models the right drivetrain. Hereinafter, each of the left drivetrain plant model and the right drivetrain plant model will also be simply referred to as a "model." The vehicle control device 10 has a function of performing feedback control using these models.

[0030] J in Figure 4 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 (load side) relative to the right axle 4R, J Ｌｔ is the left wheel inertia (moment of inertia of the left wheel 5L alone), J Ｒｔ is the right wheel inertia (the moment of inertia of the right wheel 5R alone). Also, in FIG. 4, the left driving side angular velocity ω Ｌｄｓ (left driving side angular acceleration), left wheel angular velocity ω ＬＷ (left wheel angular acceleration), right drive side angular velocity ω Ｒｄｓ (right drive side angular acceleration), right wheel angular velocity ω ＲＷ The differential value (right wheel angular acceleration) of

[0031] The model of this embodiment uses the inertia J of the motor 2, which is the driving source of the vehicle 1. Ｍ (Moment of inertia, inertia) ＬＭ , J ＲＭ and stiffness (axle stiffness K Ｓ spring) and viscosity (axle viscosity D Ｓ The spring damper is designed with a load side inertia J according to the vehicle body weight M of the vehicle 1. ＬＷ , J ＲＷ5A is a schematic diagram corresponding to the left drivetrain plant model, and FIG. 5B is a schematic diagram corresponding to the right drivetrain plant model.

[0032] As shown in FIG. 5A, the left drivetrain plant model is ＬＭ and rigidity K Ｓ and viscosity D Ｓ The spring damper is designed with the load side inertia (nominal inertia) J ＬＷ This is a two-inertia model consisting of the drive inertia J ＬＭ is the inertia J of the motor 2L which is the driving source of the vehicle 1. Ｍ In addition, the load inertia J ＬＷ is, for example, the vehicle weight M (wheel equivalent) and the actual slip ratio λ of the left wheel 5L. Ｌ The value depends on the drive inertia J ＬＭ Calculation formula and load inertia J ＬＷ The definition of is shown below.

[0033]

[0034] As shown in FIG. 5B, the right drivetrain plant model also has the drive-side inertia J ＲＭ and rigidity K Ｓ and viscosity D Ｓ The spring damper is designed with the load side inertia (nominal inertia) J ＲＷ This is a two-inertia model consisting of the drive inertia J ＲＭ is the inertia J of motor 2R Ｍ In addition, the load inertia J ＲＷ is, for example, the vehicle weight M (wheel equivalent) and the actual slip ratio λ of the right wheel 5R. Ｒ The value depends on the drive inertia J ＲＭ Calculation formula and load inertia J ＲＷ The definition of is shown below.

[0035]

[0036] The correction value calculation unit 11 calculates a correction value (feedback correction value) used in feedback control. For example, when the feedback control amount includes an integral term, the correction value calculation unit 11 calculates an integral correction value. When the feedback control amount includes a proportional term, the correction value calculation unit 11 calculates a proportional correction value, and when the feedback control amount includes a differential term, the correction value calculation unit 11 calculates a differential correction value. For this calculation, the correction value calculation unit 11 includes at least a calculation unit 21 and a setting unit 22. The correction values ​​calculated here are transmitted to the control unit 12. In this embodiment, at least one correction value is set to the load inertia J ＬＷ , J ＲＷ The setting is made according to the

[0037] The control unit 12 includes an FB control unit 13 that uses the above-mentioned plant model to perform feedback control to reduce the difference between the actual wheel speed and the target wheel speed (wheel speed deviation). The FB control unit 13 performs the feedback control using the correction value set by the setting unit 22 of the correction value calculation unit 11. This allows the friction coefficient of the road surface on which the vehicle 1 actually travels to be reflected in the feedback control with high accuracy, improving the responsiveness of the feedback control.

[0038] 6 is a block diagram for explaining specific control contents of the vehicle control device 10 including the correction value calculation unit 11 and the control unit 12. The correction value calculation unit 11 is provided with a calculation unit 21, a setting unit 22, and a condition determination unit 23. The control unit 12 is provided with an FB control unit 13 having a P control unit 27 and an I control unit 28, as well as a traction operation determination unit 25 and an FF control unit 26.

[0039] The calculation unit 21 calculates the load side inertia J based on the motor torque output by the motor 2 and the motor angular velocity or the wheel speed. ＬＷ , J ＲＷ The load inertia J of the left drivetrain is calculated. ＬＷ is calculated based on the following equation 5, for example: ＬＷ , J ＲＷWhen calculating the angular velocity, the value detected by the resolver 17 may be used as the motor angular velocity, or the value detected by the wheel speed sensor 18 may be converted into the motor angular velocity and used.

[0040]

[0041] Similarly, the load inertia J is calculated using the wheel speed. ＬＷ , J ＲＷ When calculating the load inertia J, the value detected by the wheel speed sensor 18 may be used as the wheel speed, or the value detected by the resolver 17 may be converted into the wheel speed and used. ＬＷ , J ＲＷ The load inertia J of the right drivetrain may be calculated. ＲＷ The calculation formula is shown below.

[0042]

[0043] Load side inertia J calculated by the calculation unit 21 ＬＷ , J ＲＷ The value of J varies depending on the friction coefficient of the road surface. For example, when the wheel speed (motor angular velocity) increases on a road surface with a relatively small friction coefficient (low μ road) and the wheel 5 slips, only the wheel 5 accelerates with almost no acceleration of the vehicle body (vehicle 1). As a result, the load inertia J calculated by the calculation unit 21 ＬＷ , J ＲＷ The value of becomes smaller, and the inertia of wheel 5 (left wheel inertia J Ｌｔ , Right wheel inertia J Ｒｔ ) is almost the same value as

[0044] On the other hand, if the wheel speed (motor angular velocity) increases on a road surface with a relatively large friction coefficient (high μ road) and the wheels grip the road surface strongly, the vehicle body accelerates together with the wheels. ＬＷ , J ＲＷ The value of the load inertia J calculated by the calculation unit 21 becomes large and becomes a value including the inertia of not only the wheels 5 but also the vehicle body (left drive train, right drive train). ＬＷ , J ＲＷBy referring to the value of , it is possible to accurately determine whether the vehicle 1 has entered a road from a high μ road to a low μ road or from a low μ road to a high μ road.

[0045] In addition, the load inertia J ＬＷ , J ＲＷ When calculating the motor angular acceleration (left drive side angular velocity ω Ｌｄｓ The differential value of the right drive side angular velocity ω Ｒｄｓ ) and the actual wheel angular acceleration (left wheel angular velocity ω ＬＷ The differential value of the right wheel angular velocity ω ＲＷ It is preferable to use the value of the time differential value of the signal (time differential value of the signal) that has passed through an LPF 24 (low pass filter). The cutoff frequency band of the LPF 24 is set to, for example, 10 Hz or more.

[0046] The setting unit 22 calculates the load inertia J ＬＷ , J ＲＷ For example, the correction value of the feedback control is set according to the load inertia J ＬＷ , J ＲＷ The larger the load inertia J, the greater the integral correction value of the feedback control, and the more the integral control input value (the value input to the calculation element of the integral term) fluctuates, thereby improving the response. ＬＷ , J ＲＷ The response may be improved by reducing the differential correction value of the feedback control as the load inertia J ＬＷ , J ＲＷ The larger the load inertia J is, the more the proportional correction value of the feedback control is increased to improve the response. ＬＷ , J ＲＷ The relationship between the magnitude of the correction value and the magnitude of the correction value can be changed as appropriate.

[0047] The setting unit 22 of this embodiment calculates the load inertia J based on the following equations 7 and 8. ＬＷ , J ＲＷ The apparent weight M of the wheel 5 and the drive train corresponding to Ｌ , M Ｒ Calculate the apparent weight M Ｌ , M Ｒ The integral correction value K ｉ Set the apparent weight MＬ is the weight corresponding to the inertia of one left wheel 5L in the left drive train, and the actual slip ratio λ of the left wheel 5L Ｌ The weight is the weight equivalent to the product of the value obtained by subtracting 1 from the vehicle weight M. Similarly, the apparent weight M Ｒ is the weight corresponding to the inertia of one wheel of the right wheel 5R in the right drivetrain, and the actual slip ratio λ of the right wheel 5R Ｒ This weight corresponds to the product of the vehicle body weight M and the value obtained by subtracting the above from 1.

[0048]

[0049] The vehicle control device 10 may be provided with a slip calculation unit (not shown) that calculates the slip state of the vehicle 1, and the actual slip ratio λ of the left and right wheels 5 may be calculated by this slip calculation unit. Ｌ , λ Ｒ The setting unit 22 may calculate the actual slip ratio λ based on the above-mentioned formulas 7 and 8. Ｌ , λ Ｒ Based on this, the apparent weight M of the wheel 5 and the drive train Ｌ , M Ｒ Calculate the apparent weight M Ｌ , M Ｒ The integral correction value K ｉ Therefore, the setting unit 22 can calculate the integral correction value according to the slip state.

[0050] FIG. 7 shows the apparent weight M of the wheels 5 and the drive train. Ｌ , M Ｒ and integral correction value K ｉ 10 is a graph illustrating the relationship between the integral correction value K ｉ The value of is, for example, the apparent weight M Ｌ , M Ｒ is a predetermined value M １ In the following range, the apparent weight M Ｌ , M Ｒ The apparent weight M Ｌ , M Ｒ is a predetermined value M １ The integral correction value K when equal to ｉ The value of the apparent weight M is set as the predetermined value A. Ｌ , M Ｒ is a predetermined value M１ If it exceeds the integral correction value K ｉ The value of the integral correction value K ｉ The value of the apparent weight M is used by the FB control unit 13 when the use condition determined by the condition determination unit 23 is satisfied. Ｌ The integral correction value K corresponding to ｉ The value of is reflected in the integral control input value of the left wheel 5L, and the apparent weight M Ｒ The integral correction value K corresponding to ｉ The value of is reflected in the integral control input value of the right wheel 5R.

[0051] The condition determination unit 23 determines the apparent weight M set by the setting unit 22. Ｌ , M Ｒ The integral correction value K corresponding to ｉ Here, for example, it is determined whether the actual wheel speed is smaller than the sum of the reference wheel speed (or target wheel speed) and a predetermined operation threshold value. If the actual wheel speed is smaller than the sum of the reference wheel speed and the predetermined operation threshold value, the integral correction value K set by the setting unit 22 is ｉ It is determined that the conditions of use are met.

[0052] The traction operation determination unit 25 determines whether or not the FB control unit 13 and the FF control unit 26 should perform drive force control (traction control) of the vehicle 1. Here, the conditions for performing traction control are determined based on, for example, the required torque and the actual wheel speed. The required torque is calculated based on the accelerator opening, brake pedal stroke, steering angle, vehicle speed, etc. Known control conditions can be applied as the conditions for performing traction control determined here.

[0053] The FF control unit 26 performs feedforward control to calculate command torques for the left and right motors 2 based on the required torque when the conditions for implementing traction control are met. Here, the command torques for the left and right motors 2 are set so that an output corresponding to at least the required torque is obtained. The command torques set by the FF control unit 26 may include, for example, a control amount for suppressing vibrations caused by interference between the left and right motors 2 and slippage between the left and right wheels 5. Note that known feedforward control related to the driving force of the vehicle 1 can be applied to the specific control content of the FF control unit 26.

[0054] The FB control unit 13 performs feedback control to correct the command torque so that the difference between the actual wheel speed and the target wheel speed (wheel speed deviation) decreases when the conditions for performing traction control are met. The FB control unit 13 of this embodiment has a P control unit 27 that calculates a correction amount proportional to the wheel speed deviation, and an I control unit 28 that calculates a correction amount corresponding to the integral value of the wheel speed deviation. The integral correction value K calculated by the correction value calculation unit 11 is ｉ The value of is used to calculate the correction amount in the I control unit 28. Note that, as the specific control content in the FB control unit 13, known feedback control related to the driving force of the vehicle 1 can be applied.

[0055] [4. Effects] (1) The vehicle control device 10 of this embodiment controls the inertia J of the motor 2, which is the drive source of the vehicle 1. Ｍ The vehicle control device 10 performs feedback control to reduce the difference between the actual wheel speed and the target wheel speed using a plant model consisting of a drive-side inertia calculated based on the load-side inertia J, a spring damper designed with stiffness and viscosity, and a load-side inertia of a magnitude corresponding to the body weight M of the vehicle 1. The vehicle control device 10 calculates the load-side inertia J based on the motor torque and the motor angular velocity or the wheel speed. ＬＷ , J ＲＷ a calculation unit 21 that calculates the load side inertia J ＬＷ , J ＲＷ and a setting unit 22 that sets a correction value for feedback control in accordance with the detected value.

[0056] In this way, the load inertia J is calculated using the motor torque and the motor angular velocity or the wheel speed. ＬＷ , J ＲＷBy calculating the load inertia J with high accuracy, even when it is difficult to grasp the change in the actual slip ratio λ (for example, during feedback control in which the drive torque is suppressed), ＬＷ , J ＲＷ can be calculated. This makes it possible to immediately detect changes in the friction coefficient of the road surface on which the vehicle 1 is traveling, and, for example, when the actual slip ratio λ changes from a low state to a high state, it is possible to quickly release the suppression of the drive torque. This improves the responsiveness of the feedback control. Furthermore, for example, when the actual slip ratio λ remains low, it is possible to stably continue the suppression of the drive torque. This makes it possible to maintain the stability of the feedback control.

[0057] (2) Load inertia J calculated by the calculation unit 21 of this embodiment ＬＷ , J ＲＷ The value of increases as the friction coefficient of the road surface increases, and decreases as the friction coefficient of the road surface decreases, resulting in the inertia of the wheel 5 (left wheel inertia J Ｌｔ , Right wheel inertia J Ｒｔ ) is obtained. Based on this characteristic, the setting unit 22 determines the load inertia J ＬＷ , J ＲＷ The larger the integral correction value K ｉ In this way, the responsiveness of the feedback control can be improved by making the integral control input value in the feedback control more likely to fluctuate as the friction coefficient of the road surface increases.

[0058] (3) The calculation unit 21 of this embodiment calculates the load inertia J based on the above-mentioned equations 5 and 6. ＬＷ , J ＲＷ This calculates the load inertia J ＬＷ , J ＲＷ The value of the left driving side angular velocity ω included in the numerator on the right side of the above equations 5 and 6 can be calculated with high accuracy. Ｌｄｓ and the right drive side angular velocity ω Ｒｄｓ The differential value of the motor angular velocity ω detected by the resolver 17 ＬＭ , ω ＲＭ Therefore, the load inertia J ＬＷ , JＲＷ This allows changes in the speed to be immediately detected, improving the responsiveness of feedback control.

[0059] (4) The control device 10 of this embodiment may be provided with a slip calculation unit that calculates the slip state of the vehicle 1. The slip calculation unit calculates the actual slip ratio λ of the left and right wheels 5. Ｌ , λ Ｒ The setting unit 22 can calculate the actual slip ratio λ based on the above-mentioned formulas 7 and 8 and FIG. Ｌ , λ Ｒ An appropriate integral correction value K according to ｉ For example, the actual slip ratio λ can be set to perform feedback control. Ｌ , λ Ｒ The apparent weight M of the wheel 5 and the drive train corresponding to Ｌ , M Ｒ Calculate the apparent weight M Ｌ , M Ｒ The integral correction value K ｉ With this configuration, the response of the feedback control can be improved.

[0060] (5) The setting unit 22 of this embodiment calculates the load inertia J based on the above equations 7 and 8. ＬＷ , J ＲＷ The apparent weight M of the wheel 5 and the drive train corresponding to Ｌ , M Ｒ Calculate the apparent weight M Ｌ , M Ｒ The integral correction value K ｉ As a result, an appropriate integral correction value K for each of the left wheel 5L and the right wheel 5R is set. ｉ Therefore, the response of the feedback control can be improved.

[0061] (6) As shown in FIG. 7, the setting unit 22 of this embodiment sets the apparent weight M Ｌ , M Ｒ is a predetermined value M １ In the following range, the apparent weight M Ｌ , M Ｒ An integral correction value K having a magnitude proportional to ｉIn this way, the apparent weight M Ｌ , M Ｒ With the increase of the integral correction value K ｉ By gradually increasing the integral control input value, the responsiveness of the feedback control can be improved while suppressing excessively sudden changes in the integral control input value, thereby increasing the stability of the feedback control.

[0062] [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.

[0063] In the above embodiment, the vehicle control device 10 is applied to the rear wheels of the vehicle 1, but a similar vehicle control device may be applied to the front wheels, or to both the front and rear wheels. By implementing control similar to that of the above embodiment in a vehicle 1 equipped with a vehicle control device 10 that controls at least the driving forces of the left and right drive trains, it is possible to achieve the same effects as those of the above embodiment.

[0064] 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 present invention is also applicable to, for example, vehicles that do not have a power distribution mechanism 3 or in-wheel motor vehicles. As shown in Figures 5(A) and 5(B), any vehicle that performs feedback control using a plant model consisting of a drive-side inertia, a spring damper, and a load-side inertia can implement control similar to that of the above embodiment, and can achieve the same effects and advantages as those of the above embodiment.

[0065] In the above embodiment, the integral correction value K ｉ Let J be the load inertia. ＬＷ , J ＲＷ However, other correction values ​​used in feedback control are set in accordance with the load inertia J ＬＷ , JＲＷ For example, the load inertia J ＬＷ , J ＲＷ The proportional correction value of the feedback control may be increased as the load inertia J ＬＷ , J ＲＷ The larger the load inertia J is, the smaller the differential correction value of the feedback control may be. ＬＷ , J ＲＷ By setting the correction value of the feedback control in accordance with the above, the responsiveness of the feedback control can be improved.

[0066] In realizing the vehicle control device according to the present invention, the driving force control methods described in the following reference documents can be referred to: ・Hiroshi Fujimoto, Takeshi Takano, Hidetoshi Nobumoto, Toshimi Okazaki, "Driving Force Control Technology Using High-Precision Slip Ratio Control," Mazda Technical Report, No. 32, pp. 228-233 (2015) ・Hiroshi Fujimoto, Junya Amada, Takayuki Miyajima, "Development and Control of an Electric Vehicle with a Variable Drive Unit System," Proceedings of the 2013 Society of Automotive Engineers of Japan Spring Academic Conference, No. 8-13, pp. 17-20 (2013) ・Masaki Yoshimura, Hiroshi Fujimoto, "Driving Torque Control Method for an Electric Vehicle Equipped with an In-Wheel Motor," Transactions of the Institute of Electrical Engineers of Japan, Vol. 131, No. 5, pp. 721-728 (2011)

[0067] The present invention is applicable to the manufacturing industry of vehicle control devices mounted on vehicles, and also applicable to the manufacturing industry of vehicles on which vehicle control devices are mounted.

[0068] REFERENCE SIGNS LIST 1 vehicle 2 motor 3 power distribution mechanism 4 axle 4L left axle 4R right axle 5 left and right wheels (wheels) 5L left wheel 5R right wheel 6 inverter 7 battery 10 vehicle control device 11 correction value calculation unit 12 control unit 13 FB control unit 14 accelerator opening sensor 15 brake sensor 16 steering angle sensor 17 resolver 18 wheel speed sensor 21 calculation unit 22 setting unit 23 condition determination unit 24 LPF (low pass filter) 25 traction operation determination unit 26 FF control unit 27 P control unit 28 I control unit

Claims

1. A vehicle control device that performs feedback control to reduce the difference between an actual wheel speed and a target wheel speed using a plant model consisting of a drive side inertia calculated based on the inertia of a motor which is the drive source of a vehicle, a spring damper designed with rigidity and viscosity, and a load side inertia of a size corresponding to the vehicle's body weight, the vehicle control device comprising: a calculation unit that calculates the load side inertia based on the motor torque and the motor angular velocity or the wheel speed; and a setting unit that sets a correction value for the feedback control according to the load side inertia.

2. The vehicle control device according to claim 1, wherein the setting unit increases the integral correction value as the load inertia increases.

3. The vehicle control device according to claim 1, wherein the calculation unit calculates the load inertia based on the motor torque, the motor angular velocity, and the wheel speed.

4. A vehicle control device according to claim 1, further comprising a slip calculation unit that calculates a slip state of the vehicle, wherein the setting unit sets an integral correction value according to the slip state.

5. A vehicle control device according to claim 1, characterized in that the setting unit calculates an apparent weight of the wheels and drive system corresponding to the load side inertia, and sets an integral correction value having a magnitude corresponding to the apparent weight.

6. A vehicle control device according to claim 5, wherein the setting unit sets an integral correction value proportional to the apparent weight when the apparent weight is within a range equal to or less than a predetermined value.

7. A vehicle control method that implements feedback control to reduce the difference between an actual wheel speed and a target wheel speed using a plant model consisting of a drive side inertia calculated based on the inertia of a motor which is the drive source of the vehicle, a spring damper designed with rigidity and viscosity, and a load side inertia of a size corresponding to the vehicle weight, characterized in that the load side inertia is calculated based on the motor torque and the motor angular velocity or the wheel speed, and a correction value for the feedback control is set according to the load side inertia.

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