Vehicle control device and vehicle control method

Abstract

A vehicle control device (10) according to the present disclosure is provided with plant models (M1, M2) including drive-side inertia (JSM, JDM) calculated on the basis of inertia (JM) of a drive source of a vehicle (1) and load-side inertia (JSL, JDL). The vehicle control device (10) is provided with a calculation unit (11) and a control unit (12). The calculation unit (11) calculates estimated wheel speeds (ωLE, ωRE) on the basis of the plant models (M1, M2) and drive source angular velocities (ωLM, ωRM). The control unit (12) performs driving force control of the vehicle (1) using the estimated wheel speed (ωLE, ωRE).

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, in driving force control of a vehicle equipped with a drive source, a target torque of the drive source is set based on various information, and the operating state of the drive source is controlled to obtain the target torque. The target torque is set based on, for example, an accelerator opening and a vehicle speed calculated from an actual wheel speed. Another known technology estimates, from a transfer function, a drive source angular velocity (e.g., a motor angular velocity) when a target torque is generated in the drive source (e.g., a motor), and controls a torque command value to obtain a desired rotation state (see Patent Document 1).

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

[0004] Information on the actual wheel speed detected by the wheel speed sensor is transmitted to the vehicle control device via an in-vehicle communication network. This causes a slight time lag before the vehicle control device grasps the actual vehicle behavior, which can reduce the controllability of the drive source. Therefore, it is conceivable to use information on the drive source angular velocity detected by sensors (e.g., resolvers) directly connected to the vehicle control device instead of the actual wheel speed, so that vehicle behavior can be grasped in almost real time.

[0005] However, the drive source angular velocity does not necessarily correspond to the actual wheel speed (the angular velocity of the actual drive wheels) and, for example, contains more vibration components than the actual wheel speed. Therefore, if the drive source angular velocity is directly reflected in the driving force control, there is a risk of malfunction due to the influence of the vibration components. Furthermore, there is a concern that the operating state of the drive source may become unstable due to vibrations in the control variables (e.g., motor torque, motor angular velocity). This issue can occur regardless of the type of drive source (e.g., motor, internal combustion engine, etc.).

[0006] 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 and stability of driving force control. In addition to this object, another object of the present invention is to achieve effects derived from the configurations shown in the "Description of Embodiments" below, which cannot be obtained with conventional technologies.

[0007] 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.

[0008] Aspect 1. The disclosed vehicle control device is a vehicle control device that includes a plant model including a drive-side inertia and a load-side inertia calculated based on the inertia of a drive source of a vehicle. The vehicle control device includes a calculation unit that calculates an estimated wheel speed based on the plant model and a drive source angular velocity, and a control unit that performs driving force control of the vehicle using the estimated wheel speed.

[0009] Aspect 2. In an aspect including the above-mentioned Aspect 1, it is preferable that the calculation unit includes a transfer function that represents the input / output characteristics of a two-inertia system that is configured from the load-side inertia, a spring damper designed in terms of stiffness and viscosity, and the drive-side inertia. Aspect 3. In an aspect including the above-mentioned Aspect 2, it is preferable that the load-side inertia is variably set based on an actual slip ratio.

[0010] Aspect 4. In the aspects including the above-mentioned Aspect 3, it is preferable that the actual slip ratio is calculated based on the actual wheel speed or the estimated wheel speed and the vehicle body speed. Aspect 5. In the aspects including the above-mentioned Aspect 3, it is preferable that the actual slip ratio is changed depending on the implementation state of the driving force control.

[0011] Aspect 6. In any of Aspects 3 to 5 above, it is preferable that the calculation unit calculates the load inertia and the actual slip ratio using a sum model that models the motion states of the left and right drive trains when the vehicle is traveling straight and a difference model that models the motion states of the left and right drive trains when the vehicle is turning.

[0012] Aspect 7. The disclosed vehicle control method uses a plant model including a drive-side inertia and a load-side inertia calculated based on the inertia of a drive source of the vehicle. This vehicle control method calculates an estimated wheel speed based on the plant model and a drive source angular velocity, and performs drive force control of the vehicle using the estimated wheel speed.

[0013] According to the disclosed vehicle control device and vehicle control method, an estimated wheel speed is calculated based on a plant model and a drive source angular velocity, and the estimated wheel speed is used to control driving force. This reduces the time lag required to grasp vehicle behavior compared to when driving force control is performed using an actual wheel speed. Furthermore, compared to when driving force control is performed using the drive source angular velocity as is, malfunctions and instability in the motor operating state can be reduced. Therefore, the controllability and stability of driving force control can be improved.

[0014] 1 is a block diagram of a vehicle to which a vehicle control device is applied. It is a schematic diagram showing an example of the structure of a vehicle's drive system. It is a speed diagram of a power distribution mechanism of a vehicle having the structure of FIG. 2. It is a schematic diagram showing the configuration of the left drive system and the right drive system of a vehicle. (A) is a schematic diagram of a sum model M1, and (B) is a schematic diagram of a difference model M2. It is a block diagram illustrating the control contents of the calculation unit and the control unit of FIG. 1. (A) to (C) are graphs showing the simulation results of investigating the relationship between the estimated wheel speed, the resolver conversion value, and the actual wheel speed.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] [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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] J in Figure 2 Ｍ is the motor inertia (moment of inertia of motor 2), J Ｌｔ represents the tire inertia of the left and right wheels 5 (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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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).

[0029] 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 detect the rotation angle of the motors 2 (drive force angular velocity, motor angular velocity ω ＬＭ , ω ＲＭ ) is output as a two-phase AC voltage. The speed of the motor 2 is determined from the time-dependent changes in these AC voltages. The wheel speed sensors 18 (18L, 18R) also detect the speed of the axle 4 (actual wheel speed ω ＬＬ , ω ＲＬ ) The vehicle control device 10 controls the output of the pair of motors 2 (2L, 2R) by controlling the operating state of the inverter 6 (6L, 6R) based on the information detected by the various sensors 14 to 18. Note that instead of the resolver 17, other sensors (hall sensors, encoders, etc.) with different internal structures or operating principles may be used.

[0030] 1, the vehicle control device 10 includes a sum model M1, a difference model M2, a calculation unit 11, and a control unit 12 as elements for controlling the driving forces of the left and right drive trains. These elements are shown by classifying the functions of the vehicle control device 10 for convenience. 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.

[0031] The sum model M1 is one of the plant models that are modeled to grasp the motion states of the left drive system (the power transmission path from the left motor 2L to the left wheel 5L) and the right drive system (the power transmission path from the right motor 2R to the right wheel 5R) when the vehicle 1 is traveling straight. The parameters input to the sum model M1 correspond to the sum of the parameters input to the left drive system and the parameters input to the right drive system, and are called "sum model state quantities." The difference model M2 is one of the plant models that are modeled to grasp the motion states of the left drive system and the right drive system when the vehicle 1 is turning. The parameters input to the difference model M2 correspond to the difference between the parameters input to the left drive system and the parameters input to the right drive system, and are called "difference model state quantities."

[0032] 4 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. 4, 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

[0033] Based on the above schematic diagrams, the sum model M1 can be modeled as shown in FIG. 5A, and the difference model M2 can be modeled as shown in FIG. 5B. The sum model M1 is suitable for use in vibration damping control and slip control for the axles 4 and left and right wheels 5 associated with the straight-line running of the vehicle 1, while the difference model M2 is suitable for use in vibration damping control and slip control for the axles 4 and left and right wheels 5 associated with the turning of the vehicle 1. In this embodiment, the sum model M1 and the difference model M2 are both two-inertia system models, but each may be configured as a multi-inertia system model including three or more moments of inertia and spring dampers. The sum model M1 and the difference model M2 may not have spring dampers, and may be any plant model including at least a drive-side inertia and a load-side inertia calculated based on the inertia of the drive source of the vehicle 1.

[0034] As shown in FIG. 5A, the sum model M1 has a sum mode drive-side inertia J ＳＭ and rigidity K Ｓ and viscosity D Ｓ The spring damper designed with the sum mode load inertia (sum mode wheel nominal inertia) J ＳＬ The sum mode 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 is.

[0035] Sum mode load inertia J ＳＬ is calculated based on the vehicle weight M (wheel equivalent), for example, J ＳＬ =J Ｌｔ + M (1-λ Ｓ )r ２ It is. Ｌｔ is the tire inertia, and r is the tire dynamic radius. Ｓ represents the sum mode actual slip ratio, for example, the actual slip ratio λ of the left wheel 5L Ｌ and the actual slip ratio λ of the right wheel 5R ＲThe sum mode drive side inertia J ＳＭ and sum mode load inertia J ＳＬ Friction may also be taken into consideration when calculating the sum model M1. The equations of motion and the like related to the sum model M1 are shown below.

[0036]

[0037] Sum mode drive side angular velocity ω Ｓｄｓ is the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ and the sum mode load side angular velocity ω ＳＬ is the left wheel angular velocity ω ＬＬ and right wheel angular velocity ω ＲＬ The sum mode drive side angular velocity ω Ｓｄｓ Sum mode load side angular velocity ω ＳＬ The ratio is given by the following transfer function:

[0038]

[0039] As shown in FIG. 5B, the differential model M2 is the differential mode drive-side inertia J, which is the equivalent inertia when a difference between the left and right wheels occurs (when turning). ＤＭ and rigidity K Ｓ and viscosity D Ｓ The spring damper is designed with the differential mode load inertia (differential mode wheel nominal inertia) J ＤＬ The difference mode drive side inertia J ＤＭ is 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 is.

[0040] Differential mode load inertia J ＤＬ is calculated based on the yaw inertia (wheel equivalent) of the vehicle 1, for example, J ＤＬ =J Ｌｔ +r ２ I Ｚ (1-λ Ｄ ) / 2(d / 2)２ It is. Ｚ is the vehicle inertia and d is the tread. Ｄ represents the difference mode actual slip ratio, for example, the actual slip ratio λ of the left wheel 5L Ｌ and the actual slip ratio λ of the right wheel 5R Ｒ The difference mode drive side inertia J ＤＭ and differential mode load inertia J ＤＬ Friction may also be taken into consideration when calculating the equation of motion etc. related to the difference model M2 are shown below.

[0041]

[0042] Differential mode drive side angular velocity ω Ｄｄｓ is the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ and is half the difference between the load side angular velocity ω ＤＬ is the left wheel angular velocity ω ＬＬ and right wheel angular velocity ω ＲＬ The difference mode driving side angular velocity ω Ｄｄｓ Difference mode load side angular velocity ω ＤＬ The ratio is given by the following transfer function:

[0043]

[0044] The calculation unit 11 calculates the sum model M1, the difference model M2, and the motor angular velocity ω ＬＭ , ω ＲＭ and the estimated wheel speed ω ＬＥ , ω ＲＥ Here, for example, the motor angular velocity ω detected by the resolver 17 is calculated. ＬＭ , ω ＲＭ Based on this, the corresponding sum mode drive side angular velocity ω Ｓｄｓ and differential mode drive side angular velocity ω Ｄｄｓ Furthermore, the sum mode driving side angular velocity ω is calculated using the above equations 6 and 12. Ｓｄｓ , differential mode drive side angular velocity ω Ｄｄｓ Based on this, the estimated wheel speed ω ＬＥ , ω ＲＥ The sum mode load side angular velocity ω corresponding to ＳＬ and differential mode load side angular velocity ω ＤＬThe sum mode load side angular velocity ω ＳＬ and differential mode load side angular velocity ω ＤＬ This information is transmitted to the control unit 12, for example.

[0045] In addition, the estimated wheel speed ω ＬＥ , ω ＲＥ When the driving force control is performed using the actual wheel speed ω obtained by the wheel speed sensor 18, ＬＬ , ω ＲＬ For example, when the wheel speed sensor 18 detects the actual wheel speed ω ＬＬ , ω ＲＬ The time lag from when the motor angular velocity ω is detected until the information is transmitted to the vehicle control device 10 can be several tens of milliseconds depending on the communication state of the in-vehicle communication network. ＬＭ , ω ＲＭ From the time when the estimated wheel speed ω ＬＥ , ω ＲＥ (sum mode load side angular velocity ω ＳＬ , differential mode load side angular velocity ω ＤＬ ) is calculated in just a few milliseconds. ＬＥ , ω ＲＥ The response of the driving force control using the estimated wheel speed ω ＬＥ , ω ＲＥ In the calculation process of the motor angular velocity ω obtained by the resolver 17, ＬＭ , ω ＲＭ Therefore, the vibration component included in the estimated wheel speed ω ＬＥ , ω ＲＥ The stability of the driving force control is improved.

[0046] The control unit 12 calculates the estimated wheel speed ω ＬＥ , ω ＲＥ In this case, for example, the estimated wheel speed ω ＬＥ , ω ＲＥ The execution condition of the driving force control is determined based on the estimated wheel speed ω ＬＥ , ω ＲＥThe value of is reflected in the control variables (motor output, motor torque, motor angular velocity, etc.) related to the driving force control. The driving force control referred to here includes, for example, traction control (control for adjusting the motor output so as to realize the required driving force without causing the wheels 5 to slip), slip control (control for stabilizing the posture of the vehicle 1 by optimizing the amount of slip of each of the left and right wheels 5), and vibration suppression control (control for adjusting the left and right motor outputs so as not to cause resonance between the left and right wheels 5).

[0047] In controlling these driving forces, the motor angular velocity ω ＬＭ , ω ＲＭ The estimated wheel speed ω is estimated from ＬＥ , ω ＲＥ By using the information of ＬＭ , ω ＲＭ In comparison with the case where the actual wheel speed ω is used as is, the vibration component can be reduced, and the rotation state of the wheel 5 can be grasped more closely to the actual situation. ＬＬ , ω ＲＬ The time lag can be reduced compared to when using the information from the previous section, and the rotation state of the wheel 5 can be grasped in real time.

[0048] 6 is a block diagram for explaining specific control details of a vehicle control device 10 including a calculation unit 11 and a control unit 12. The calculation unit 11 is provided with a plant model including a sum model M1 and a difference model M2. The calculation unit 11 also includes a sum / difference conversion unit 21, an actual slip ratio calculation unit 22, an estimation unit 23, and a left / right conversion unit 24. The control unit 12 is provided with a flag setting unit 31, an FF control amount setting unit 32, and an FB control amount setting unit 33.

[0049] The sum-difference converter 21 converts the motor angular velocity ω detected by the resolver 17 into ＬＭ , ω ＲＭ The sum mode driver angular velocity ω in the sum model M1 and the difference model M2 Ｓｄｓ and differential mode drive side angular velocity ω Ｄｄｓ Here, for example, the motor angular velocity ω ＬＭ , ω ＲＭ Based on the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ is calculated. In addition, the sum mode driving side angular velocity ωＳｄｓ The value of the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ The difference mode driving side angular velocity ω Ｄｄｓ The value of the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ The motor angular velocity ω ＬＭ , ω ＲＭ and the left driving side angular velocity ω Ｌｄｓ and right drive side angular velocity ω Ｒｄｓ The relational expression is shown below as an example.

[0050]

[0051] The actual slip ratio calculation unit 22 calculates the actual slip ratio λ of the left and right wheels 5. Ｌ , λ Ｒ and the corresponding sum mode actual slip ratio λ Ｓ and the difference mode actual slip ratio λ Ｄ The actual slip ratio λ Ｌ , λ Ｒ is, for example, the reference wheel speed V of the left and right wheels 5 ｒｌｘ , V ｒｒｘ and the actual wheel speed ω ＬＬ , ω ＲＬ The wheel speed V corresponding to ＬＲ (=rω ＬＬ ), V ＲＲ (=rω ＲＬ ) and is calculated based on V ｘ is the vehicle speed, and γ is the yaw rate.

[0052] In addition, the sum mode actual slip ratio λ Ｓ The value of is, for example, the actual slip ratio λ Ｌ , λ Ｒ The difference mode actual slip ratio λ is half the sum of Ｄ The value of is, for example, the actual slip ratio λ Ｌ , λ Ｒ The actual wheel speed ω ＬＬ , ω ＲＬ and the corresponding wheel speed V ＬＲ , V ＲＲ Instead of the estimated wheel speed ω obtained in the previous calculation cycle, ＬＥ , ω ＲＥand the corresponding estimated wheel speed V ＬＥ (=rω ＬＥ ), V ＲＥ (=rω ＲＥ ) to calculate the actual slip ratio λ Ｌ , λ Ｒ may be calculated.

[0053]

[0054] The estimation unit 23 estimates the estimated wheel speed ω ＬＥ , ω ＲＥ The sum mode load side angular velocity ω corresponding to ＳＬ and differential mode load side angular velocity ω ＤＬ The estimation unit 23 calculates the sum mode driving side angular velocity ω Ｓｄｓ Based on the sum mode load side angular velocity ω ＳＬ The sum mode load inertia J in Equation 6 is calculated. ＳＬ The value of is calculated using Equation 5 and the sum mode actual slip ratio λ Ｓ The estimation unit 23 calculates the angular velocity ω based on the equation 12 and the differential mode driving side angular velocity ω Ｄｄｓ Based on the difference mode load side angular velocity ω ＤＬ The difference mode load side inertia J in Equation 12 is calculated. ＤＬ The value of is calculated using Equation 11 and the difference mode actual slip ratio λ Ｄ It is calculated based on the following.

[0055] The left-right converter 24 converts the sum mode load side angular velocity ω calculated by the estimator 23 into ＳＬ and differential mode load side angular velocity ω ＤＬ The estimated wheel speed of the left and right wheels 5 is the estimated left wheel angular velocity ω ＬＥ and the estimated angular velocity of the right wheel ω ＲＥ Here, for example, the sum mode load side angular velocity ω ＳＬ and differential mode load side angular velocity ω ＤＬ The sum of the estimated left wheel angular velocity ω ＬＥ The sum mode load side angular velocity ω ＳＬ and differential mode load side angular velocity ω ＤＬ The difference between the estimated right wheel angular velocity ω ＲＥ It is calculated as:

[0056] The control unit 12 calculates the estimated angular velocities ω of the left and right wheels 5 calculated by the calculation unit 11. ＬＥ , ωＲＥ The driving force control is performed using the estimated wheel speed, the required torque, the estimated vehicle speed, the longitudinal acceleration, the lateral acceleration, etc. The required torque is calculated based on, for example, the accelerator opening and the vehicle speed. The estimated vehicle speed is calculated based on the actual wheel speed ω detected by the wheel speed sensor 18. ＬＬ , ω ＲＬ The longitudinal acceleration and the lateral acceleration are calculated based on the actual wheel speed ω detected by the wheel speed sensor 18. ＬＬ , ω ＲＬ The acceleration may be calculated based on the acceleration sensor or may be detected by a longitudinal acceleration sensor or a lateral acceleration sensor (not shown).

[0057] The flag setting unit 31 sets a control flag X corresponding to the implementation state of driving force control (for example, traction control, slip control, etc.). The control flag X is a binary flag that is set to 1 when driving force control is being implemented and is set to 0 when driving force control is not being implemented. For example, when the estimated wheel speed ω ＬＥ , ω ＲＥ When the difference between the estimated wheel speed ω and the target wheel speed is equal to or greater than a predetermined difference, it is determined that the tires have begun to slip, and the control flag X is set to 1. ＬＥ , ω ＲＥ When the difference between the actual wheel speed and the target wheel speed becomes less than a predetermined difference, it is determined that the wheel is no longer slipping, and the control flag X is set to 0.

[0058] The FF control amount setting unit 32 sets an FF torque related to feedforward control (open loop control) among drive force controls (for example, traction control, slip control, etc.), and sets the actual wheel speed ω of the left and right wheels 5. ＬＬ , ω ＲＬ The FF control amount setting unit 32 sets the FF torque when the control flag X set by the flag setting unit 31 is 1.

[0059] The FB control amount setting unit 33 sets the FB torque related to feedback control (closed loop control) among the driving force controls (for example, traction control, slip control, etc.), and sets the actual wheel speed ω of the left and right wheels 5. ＬＬ , ωＲＬ and the target wheel speed is set as a feedback correction amount. The FB control amount setting unit 33 sets the FB torque when the control flag X set by the flag setting unit 31 is 1. The sum of the FB torque set here and the FF torque set by the FF control amount setting unit 32 is reflected in the final command torque of the motor 2.

[0060] In addition, the motor angular velocity ω ＬＭ , ω ＲＭ The estimated wheel speed (left wheel estimated angular velocity ω ＬＥ and the estimated angular velocity of the right wheel ω ＲＥ The value of the left wheel estimated angular velocity ω) may be used to set the FF torque in the FF control amount setting unit 32 or the FB torque in the FB control amount setting unit 33. In addition, for example, when a second control unit that adds a torque correction amount for vibration damping control is provided in the subsequent stage of the control unit 12, the value of the left wheel estimated angular velocity ω ＬＥ and the estimated angular velocity of the right wheel ω ＲＥ The value of may be used for control in the second control unit.

[0061] 7A to 7C show the actual wheel speed ω ＬＬ , ω ＲＬ (detection value of wheel speed sensor 18) and motor angular velocity ω ＬＭ , ω ＲＭ (detection value of resolver 17) converted into a wheel speed equivalent value (resolver converted value ω Ｌｄｓ , ω Ｒｄｓ ) and estimated wheel speed ω ＬＥ , ω ＲＥ 7A and 7B are graphs showing the results of a simulation (computer simulation) investigating the relationship between the coefficient of friction (λ) and the actual slip ratio (λ). Fig. 7A shows the results for a road surface with a relatively high coefficient of friction (high μ road), while Figs. 7B and 7C show the results for a road surface with a relatively low coefficient of friction (low μ road). In Figs. 7A and 7B, it is assumed that the actual slip ratio (λ) is close to 0%, and in Fig. 7C, it is assumed that the actual slip ratio (λ) is close to 100%.

[0062] As shown in FIG. 7A, when starting on a road surface with a relatively high friction coefficient, the actual wheel speed ω ＬＬ , ω ＲＬ The resolver conversion value ω Ｌｄｓ, ω Ｒｄｓ Also, the resolver conversion value ω Ｌｄｓ , ω Ｒｄｓ is the actual wheel speed ω ＬＬ , ω ＲＬ Therefore, if the resolver equivalent value ω Ｌｄｓ , ω Ｒｄｓ For example, if the driving force control based on the estimated wheel speed ω is performed before the vehicle 1 starts moving, a malfunction may occur due to the influence of the vibration component. ＬＥ , ω ＲＥ and the target wheel speed is erroneously determined to be equal to or greater than a predetermined difference, the control flag X is set to 1, and driving force control (for example, slip control in which the motor torque is suppressed) is initiated.

[0063] In contrast, the estimated wheel speed ω ＬＥ , ω ＲＥ is the resolver equivalent value ω Ｌｄｓ , ω Ｒｄｓ The estimated wheel speed ω ＬＥ , ω ＲＥ is the actual wheel speed ω ＬＬ , ω ＲＬ Therefore, the estimated wheel speed ω ＬＥ , ω ＲＥ By carrying out the driving force control based on the above, erroneous determination of the control flag X is suppressed, and the controllability and stability of the driving force control are improved.

[0064] As shown in FIG. 7B, even when starting on a road surface with a relatively low friction coefficient, the estimated wheel speed ω ＬＥ , ω ＲＥ is the resolver equivalent value ω Ｌｄｓ , ω Ｒｄｓ The vibration component is smaller than that of the estimated wheel speed ω ＬＥ , ω ＲＥ By carrying out the driving force control based on the estimated wheel speed ω, the controllability and stability of the driving force control are improved. ＬＥ , ω ＲＥ The timing of the rise of the actual wheel speed ω ＬＬ , ω ＲＬ This is slightly delayed compared to the timing of the rise of the actual wheel speed ωＬＬ , ω ＲＬ Estimated wheel speed ω ＬＥ , ω ＲＥ The deviation of the actual slip ratio λ is caused by assuming 0% even though the friction coefficient of the road surface is low (i.e., the estimated wheel speed ω ＬＥ , ω ＲＥ This is thought to be due to the increasing calculation error.

[0065] 7C is a graph showing the results of a simulation in which an actual slip ratio λ is assumed to be approximately 100%. In this graph, the estimated wheel speed ω ＬＥ , ω ＲＥ The timing of the rise of the actual wheel speed ω ＬＬ , ω ＲＬ In this way, by regarding the actual slip ratio λ as a variable value that can fluctuate up to a certain large value, rather than regarding the actual slip ratio λ as a fixed value close to 0%, the estimated wheel speed ω ＬＥ , ω ＲＥ It can be seen that the calculation error of is reduced, and not only the controllability and stability of the driving force control but also the responsiveness are improved.

[0066] [5. Effects] (1) The vehicle control device 10 of this embodiment calculates the inertia J of the drive source (motor 2) of the vehicle 1. Ｍ The driving side inertia J calculated based on ＳＭ , J ＤＭ and load inertia J ＳＬ , J ＤＬ The vehicle control device 10 includes a calculation unit 11 and a control unit 12. The calculation unit 11 calculates the plant models M1 and M2 and the motor angular velocity ω ＬＭ , ω ＲＭ (drive source angular velocity) and the estimated wheel speed ω ＬＥ , ω ＲＥ The control unit 12 calculates the estimated wheel speed ω ＬＥ , ω ＲＥ Driving force control is performed using

[0067] With this configuration, the actual wheel speed ω ＬＬ , ωＲＬ In comparison with the case where driving force control is performed using the motor angular velocity ω, the time lag for grasping the behavior of the vehicle 1 can be reduced, and the rotation state of the wheels 5 can be grasped in real time. ＬＭ , ω ＲＭ Since vibration components are reduced compared to when driving force control is performed using the above formula as is, it is possible to suppress malfunctions and instability in the motor's operating state, and it is possible to grasp the rotational state of the wheels 5 more closely to the actual situation. As a result, the responsiveness, stability, and controllability of the driving force control can be improved.

[0068] For example, in traction control, it is possible to generate a motor output that matches the required driving force while suppressing slip of the wheels 5 with high precision. In addition, in slip control, it is possible to optimize the amount of slip of each of the left and right wheels 5, thereby improving the stability of the vehicle 1's posture when turning. In addition, in vibration suppression control, it is possible to effectively suppress resonance between the left and right wheels 5.

[0069] (2) The calculation unit 11 calculates the load inertia J ＳＬ , J ＤＬ and rigidity K Ｓ and viscosity D Ｓ The spring damper is designed with the inertia J ＳＭ , J ＤＭ With this configuration, the load side angular velocity ω ＳＬ , ω ＤＬ can be accurately estimated, and the estimated wheel speed ω ＬＥ , ω ＲＥ Therefore, the response, stability, and controllability of the driving force control can be improved.

[0070] (3) The above load inertia J ＳＬ , J ＤＬ is the actual slip ratio λ Ｓ , λ Ｄ In this way, the actual slip ratio λ Ｓ , λ Ｄ Let J be the load inertia. ＳＬ , J ＤＬ By reflecting this in the estimated wheel speed ω ＬＥ , ω ＲＥFor example, as shown in FIG. 7C, the calculation accuracy of the actual wheel speed ω ＬＬ , ω ＲＬ and estimated wheel speed ω ＬＥ , ω ＲＥ Therefore, the response, stability, and controllability of the driving force control can be improved.

[0071] (4) The actual slip ratio λ Ｓ , λ Ｄ is expressed by, for example, the actual wheel speed ω ＬＬ , ω ＲＬ (or estimated wheel speed ω ＬＥ , ω ＲＥ ) and vehicle speed V ｘ In this way, the actual rotational state of the left and right wheels 5 is calculated based on the load inertia J ＳＬ , J ＤＬ By reflecting this in the estimated wheel speed ω ＬＥ , ω ＲＥ Therefore, the response, stability, and controllability of the driving force control can be improved.

[0072] (5) The calculation unit 11 calculates the load inertia J by using a sum model M1 that models the motion states of the left and right drive trains when the vehicle 1 travels straight and a difference model M2 that models the motion states of the left and right drive trains when the vehicle 1 turns. ＳＬ , J ＤＬ and actual slip ratio λ Ｓ , λ Ｄ In this way, by using the sum model M1 and the difference model M2, the load inertia J ＳＬ , J ＤＬ and actual slip ratio λ Ｓ , λ Ｄ can be calculated with high accuracy, and the response, stability, and controllability of the driving force control can be improved.

[0073] (6) The above plant models M1 and M2 include transfer functions shown in Equations 6 and 12. These transfer functions are expressed by the drive-side angular velocity ω Ｓｄｓ , ω Ｄｄｓ Load side angular velocity ω ＳＬ , ω ＤＬ Ratio of load inertia J ＳＬ , JＤＬ By using such a transfer function, the load side angular velocity ω ＳＬ , ω ＤＬ can be calculated with high accuracy, and the estimated wheel speed ω ＬＥ , ω ＲＥ Therefore, the response, stability, and controllability of the driving force control can be improved.

[0074] (7) The above load inertia J ＳＬ , J ＤＬ is calculated based on Equation 5 and Equation 11. Equation 5 is the load inertia J ＳＬ and tire inertia J Ｌｔ and the sum mode actual slip ratio λ Ｓ and the vehicle weight M. Equation 11 defines the relationship between the load inertia J ＤＬ and tire inertia J Ｌｔ and the difference mode actual slip ratio λ Ｄ and vehicle inertia I Ｚ By using these equations, the load inertia J in each of the sum model and the difference model is ＳＬ , J ＤＬ can be calculated with high accuracy, and the estimated wheel speed ω ＬＥ , ω ＲＥ Therefore, the response, stability, and controllability of the driving force control can be improved.

[0075] [6. 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.

[0076] 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.

[0077] In the above embodiment, the vehicle 1 is illustrated as being equipped with a pair of motors 2 as drive sources, but an internal combustion engine may be used instead of the motors 2, and the specific type of drive source is not important. Also, in the above embodiment, the drive force control of the motors 2 is described in detail, but similar drive force control can be applied to other drive sources, for example, it may be applied to the drive force control of an internal combustion engine. In this case, for example, the estimated wheel speed ω is calculated based on the sum model M1, the difference model M2, and the engine rotation speed (drive force angular velocity) obtained by the engine rotation speed sensor. ＬＥ , ω ＲＥ can be calculated.

[0078] Furthermore, although the vehicle 1 is illustrated as having a vehicle drive system (DM-AYC system) including a pair of motors 2 and a power distribution mechanism 3, the present invention is also applicable to vehicles that do not have a power distribution mechanism 3 or in-wheel motor vehicles. ＳＭ , J ＤＭ and load inertia J ＳＬ , J ＤＬ In the case of a vehicle 1 that performs driving force control using a plant model consisting of the above, it is possible to perform control similar to that of the above embodiment, and it is possible to obtain the same effects and advantages as those of the above embodiment.

[0079] In the actual slip ratio calculation unit 22 of the above embodiment, the reference wheel speed V ｒｌｘ , V ｒｒｘ and actual wheel speed V ＬＲ , V ＲＲ Based on the actual slip ratio λ Ｌ , λ Ｒ is calculated, but the simple actual slip ratio λ according to the value of the control flag X is Ｌ , λ Ｒ For example, when the control flag X is 1, the actual slip ratio λ of the left and right wheels 5 may be calculated as follows: Ｌ , λ Ｒ The value of (a) may be set to a first predetermined value (for example, 1, which is a value corresponding to a slip ratio of 100%). The first predetermined value can be set arbitrarily within the range of, for example, 0 to 1.

[0080] When the control flag X is 0, the actual slip ratio λ of the left and right wheels 5 is Ｌ, λ Ｒ Alternatively, the value of the actual slip ratio λ may be set to a second predetermined value (for example, 0, which corresponds to a slip ratio of 0%). The second predetermined value can be set arbitrarily within the range from 0 to the first predetermined value. In this way, the actual slip ratio λ may be adjusted depending on the implementation state of the driving force control. Ｌ , λ Ｒ By changing the above, it is possible to perform driving force control with a simple configuration and with relatively high accuracy.

[0081] 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)

[0082] 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.

[0083] REFERENCE SIGNS LIST 1 vehicle 2 motor (drive source) 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 calculation unit 12 control unit 14 accelerator opening sensor 15 brake sensor 16 steering angle sensor 17 resolver 18 wheel speed sensor 21 sum / difference conversion unit 22 actual slip ratio calculation unit 23 estimation unit 24 left / right conversion unit 31 flag setting unit 32 FF control amount setting unit 33 FB control amount setting unit M1 sum model (plant model) M2 difference model (plant model) J ＳＭ , J ＤＭ Drive side inertia J ＳＬ , J ＤＬ Load side inertia ω ＬＭ , ω ＲＭMotor angular velocity (drive source angular velocity) ω ＬＥ , ω ＲＥ Estimated wheel speed (estimated angular velocity of left and right wheels 5)

Claims

1. A vehicle control device having a plant model including a drive side inertia and a load side inertia calculated based on the inertia of a drive source of a vehicle, the vehicle control device comprising: a calculation unit that calculates an estimated wheel speed based on the plant model and a drive source angular velocity; and a control unit that performs driving force control of the vehicle using the estimated wheel speed.

2. The vehicle control device according to claim 1, characterized in that the calculation unit includes a transfer function that represents the input / output characteristics of a two-inertia system composed of the load-side inertia, a spring damper designed in terms of stiffness and viscosity, and the drive-side inertia.

3. The vehicle control device according to claim 2, wherein the load side inertia is variably set based on an actual slip ratio.

4. A vehicle control device according to claim 3, characterized in that the actual slip ratio is calculated based on an actual wheel speed or the estimated wheel speed and a body speed of the vehicle.

5. A vehicle control device according to claim 3, characterized in that the actual slip ratio is changed depending on the implementation state of the driving force control.

6. A vehicle control device as claimed in any one of claims 3 to 5, characterized in that the calculation unit calculates the load inertia and the actual slip ratio using a sum model that models the motion states of the left and right drive systems when the vehicle is traveling straight and a difference model that models the motion states of the left and right drive systems when the vehicle is turning.

7. A vehicle control method using a plant model including drive side inertia and load side inertia calculated based on the inertia of a vehicle's drive source, the vehicle control method comprising: calculating an estimated wheel speed based on the plant model and a drive source angular velocity; and performing drive force control of the vehicle using the estimated wheel speed.

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