Vehicle control device, vehicle control method, and vehicle control program

Abstract

To provide a vehicle control device, a vehicle control method, and a vehicle control program that make a driver of a vehicle recognize that a slip has occurred and suppress a stuck state of the vehicle.SOLUTION: A vehicle control device (10) includes an inverter control section (32) configured to control an inverter (151) that drives a motor (150) mounted on a vehicle (100) for driving the vehicle, and a control section (31) configured to perform control of advancing a timing of starting torque suppression of the motor so as to suppress a slip of a drive wheel of the vehicle at a start of the vehicle when a gradient of a road surface on which the vehicle is present tends to increase.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle control device, a vehicle control method, and a vehicle control program. [Background technology]

[0002] Patent Document 1 discloses technology related to a tire spin suppression function (TRaction Control: TRC). When a vehicle's drive wheels slip, TRC suppresses torque, thereby performing feedback (F / B) control of the rotational speed of the drive wheels to optimize the slip ratio. In TRC, an initial slip occurs due to a control delay before torque suppression begins. This initial slip makes it possible for the driver of the vehicle to recognize that the drive wheels are slipping. In this way, conventional technology allows a certain degree of initial slip to serve as a warning to encourage safe driving. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 02-305333 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the conventional technology of Patent Document 1, for example, if a vehicle parked on a snowy uphill road attempts to start, and the drive wheels experience initial slip, the rotation of the drive wheels may melt the snow, reducing the coefficient of friction (hereinafter, μ) of the road surface, i.e., the snow surface. If the road surface μ decreases, the vehicle may be unable to climb the slope and may become stuck on the road. On the other hand, on flat roads where there is no risk of getting stuck, it is desirable to control torque suppression with a priority on making the driver of the vehicle aware that a slip has occurred. As such, the conventional technology leaves room for improvement in terms of both making the driver of the vehicle aware of the occurrence of a slip and preventing the vehicle from getting stuck.

[0005] The present disclosure aims to provide a vehicle control device, a vehicle control method, and a vehicle control program that can simultaneously make a vehicle driver aware that a slip has occurred and prevent the vehicle from getting stuck. [Means for solving the problem]

[0006] A vehicle control device (10) according to a first aspect of the present disclosure includes an inverter control unit (32) that controls an inverter (151) that drives a prime mover (150) for driving a vehicle (100) mounted on the vehicle, and a control unit (31) that executes control to advance the timing of starting torque suppression of the prime mover so as to suppress slippage of the drive wheels of the vehicle when the gradient of the road surface on which the vehicle is located tends to increase when the vehicle starts moving.

[0007] A vehicle control program (23A) according to a second aspect of the present disclosure causes at least one processor (21A) to execute processing including controlling an inverter (151) that drives a prime mover (150) for driving a vehicle (100) and that, when the gradient of a road surface on which the vehicle is located tends to increase, advances the timing of starting torque suppression of the prime mover so as to suppress slippage of drive wheels of the vehicle when the vehicle starts moving.

[0008] A vehicle control method according to a third aspect of the present disclosure executes a process in which at least one processor (21A) controls an inverter (151) that drives a prime mover (150) for driving a vehicle (100) and that, when the gradient of a road surface on which the vehicle is located tends to increase, advances the timing at which torque suppression of the prime mover is started so as to suppress slippage of drive wheels of the vehicle when the vehicle starts moving. [Effects of the Invention]

[0009] According to the present disclosure, a vehicle control device, a vehicle control method, and a vehicle control program are provided that can simultaneously make the driver of the vehicle aware that a slip has occurred and prevent the vehicle from getting stuck. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle 100. As shown in FIG. [Figure 2] FIG. 2 is a block diagram showing an example of the hardware configuration of the vehicle control device 10. [Figure 3] FIG. 3 is a block diagram illustrating an example of the sensor group 200. As shown in FIG. [Figure 4] FIG. 4 is a block diagram showing an example of the functional configuration of the CPU 21A of the vehicle control device 10. As shown in FIG. [Figure 5] FIG. 5 is a diagram showing an example of the configuration of a driving unit 152 including a rotating electric machine 150 and an inverter 151. [Figure 6A] FIG. 6A is a flowchart for explaining the slip suppression process performed by the vehicle control device 10. [Figure 6B] FIG. 6B is a flowchart for explaining the slip suppression process performed by the vehicle control device 10. [Figure 7A] FIG. 7A is a diagram for explaining the slip suppression process performed by the vehicle control device 10. As shown in FIG. [Figure 7B] FIG. 7B is a diagram for explaining the slip suppression process performed by the vehicle control device 10. As shown in FIG. [Figure 8A] FIG. 8A is a diagram for explaining the slip suppression process performed by the vehicle control device 10. As shown in FIG. [Figure 8B] FIG. 8B is a diagram for explaining the slip suppression process performed by the vehicle control device 10. As shown in FIG. [Figure 9A] FIG. 9A is a diagram for explaining torque suppression control according to the present disclosure when initial slip occurs. [Figure 9B] FIG. 9B is a diagram for explaining torque suppression control according to the present disclosure when initial slip occurs. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] A vehicle control device 10 according to this embodiment is mounted on a vehicle 100 and configured as a device for controlling the vehicle 100. Prior to describing the vehicle control device 10, the configuration of the vehicle 100 will be described with reference to FIG.

[0013] FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle 100. The vehicle 100 is a vehicle that travels based on the driving operation of a driver. The vehicle 100 of the present disclosure may be interpreted as an electric vehicle that drives the rear wheels and steers the front wheels. The vehicle 100 includes a body 101, wheels 111, 112, 121, and 122, a rotating electric machine 150 for driving the vehicle, and a battery (BATT) 160.

[0014] The vehicle body 101 is the main body of the vehicle 100, and is referred to as the "body." The wheel 111 is a wheel provided on the front left side of the vehicle body 101, and the wheel 112 is a wheel provided on the rear right side of the vehicle body 101. The wheels 111 and 112, which are front wheels, are provided as driven wheels in this embodiment.

[0015] Wheel 121 is a wheel provided on the rear left side of body 101. Wheel 122 is a wheel provided on the rear right side of body 101. In this embodiment, wheels 121 and 122, which are rear wheels, are provided as drive wheels. That is, wheels 121 and 122 rotate by the driving force of rotating electric machine 150, causing vehicle 100 to travel.

[0016] The rotating electric machine 150 is an example of a prime mover that generates torque for driving the vehicle 100 .

[0017] As described above, the vehicle 100 of this embodiment is configured as a so-called "rear-wheel drive" vehicle. Alternatively, the vehicle 100 may be configured as a front-wheel drive vehicle, that is, a vehicle in which the front wheels are driven and the front wheels are steered. The vehicle 100 may also be configured as a four-wheel drive vehicle, that is, a vehicle in which the front and rear wheels are driven and the front wheels are steered. In the former case, a separate rotating electric machine 150 for driving the front wheels may be provided instead of the rotating electric machine 150 for driving the rear wheels. In the latter case, a separate rotating electric machine 150 for driving the front wheels may be provided in addition to the rotating electric machine 150 for driving the rear wheels.

[0018] A brake device 131 is provided on the wheel 121, and a brake device 132 is provided on the wheel 122. Both brake devices 131 and 132 are braking devices that apply braking force to the wheels by hydraulic pressure. Such braking devices may be provided not only on the driving wheels but also on the wheels 111 and 112, which are driven wheels. The operation of the brake devices 131 and 132 is controlled by a brake ECU (Electronic Control Unit) 20.

[0019] The rotating electric machine 150 is a device that receives a supply of electric power from the battery 160 and generates a driving force for rotating the wheels 121, 122, i.e., a driving force required for the vehicle 100 to travel. The rotating electric machine 150 is, for example, a so-called "motor generator" (MG). The driving force generated by the rotating electric machine 150 is transmitted to each of the wheels 121, 122 via the powertrain unit 140, causing the wheels 121, 122 to rotate. Note that the exchange of electric power between the battery 160 and the rotating electric machine 150 is performed via an inverter 151.

[0020] The rotating electric machine 150 generates a driving force for accelerating the vehicle 100, and can also generate a braking force by regeneration to decelerate the vehicle 100. Braking of the vehicle 100 can be performed by the rotating electric machine 150 or by the brake devices 131 and 132. Accelerating the vehicle 100 can be interpreted as increasing the accelerator opening.

[0021] The battery 160 is a storage battery for supplying driving power to the rotating electric machine 150. In this embodiment, as an example, a lithium ion battery is used as the battery 160. Regenerative power generated by the rotating electric machine 150 during braking is supplied to the battery 160 via the inverter 151 and is charged into the battery 160.

[0022] The vehicle 100 is provided with a brake ECU 20 separate from the vehicle control device 10. Both the vehicle control device 10 and the brake ECU 20 are configured as computer systems having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. These can communicate with each other bidirectionally via a network provided in the vehicle 100. Details of the hardware configuration of the vehicle control device 10 will be described later.

[0023] The vehicle control device 10 and the brake ECU 20 do not have to be separated into two devices as in the present embodiment. For example, the functions of the brake ECU 20 may be integrated into the vehicle control device 10. When realizing the functions of the vehicle control device 10 described later, the specific device configuration is not particularly limited.

[0024] Next, an example of the hardware configuration of the vehicle control device 10 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the hardware configuration of the vehicle control device 10. The vehicle control device 10 includes a control unit 21, a communication unit 22, and a storage unit 23.

[0025] The control unit 21 is configured as a device including a general computer. The control unit 21 includes a CPU 21A, a ROM 21B, a RAM 21C, and an input / output interface (I / O) 21D. The CPU 21A, the ROM 21B, the RAM 21C, and the I / O 21D are connected to each other via a bus 21E. The bus 21E includes a control bus, an address bus, a data bus, etc.

[0026] The I / O 21D is connected to a communication unit 22, a storage unit 23, and a sensor group 200. The communication unit 22 is an interface for communicating with external devices such as the brake ECU 20 and the rotating electrical machine 150.

[0027] The storage unit 23 is configured as a non-volatile external storage device such as a hard disk, etc. The storage unit 23 stores a vehicle control program 23A.

[0028] The CPU 21A is an example of a computer. The term "computer" here refers to a processor in a broad sense, and includes a general-purpose processor (e.g., the CPU 21A) or a dedicated processor (e.g., a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device, etc.).

[0029] The vehicle control program 23A may be stored in a non-volatile non-transitory recording medium or distributed via a network and appropriately installed in the vehicle control device 10, thereby being stored in the storage unit 23. The vehicle control program 23A may also be appropriately updated by so-called OTA (Over The Air).

[0030] An example of a non-volatile non-transitory recording medium is a CD-ROM (Compact Disc Examples include optical disks, hard disk drives (HDDs), digital versatile discs (DVD-ROMs), flash memories, and memory cards.

[0031] Vehicle 100 may be provided with a large number of sensors for measuring various physical quantities. Fig. 3 is a block diagram showing an example of sensor group 200. Sensor group 200 may include a wheel speed sensor 201, an acceleration sensor 202, a current sensor 203, an exterior camera 204, an accelerator sensor 205, an external temperature sensor 206, and a gradient sensor 207. Sensor group 200 may also include a brake sensor 208, a parking sensor 209, a yaw rate sensor 210, a rotation speed sensor 211, and a cooling sensor 212.

[0032] The wheel speed sensor 201 is a sensor for measuring the number of rotations per unit time of the wheel 111, etc. Although the wheel speed sensor 201 is provided individually for each of the four wheels 111, 112, 121, and 122, in FIG. 3, the wheel speed sensor 201 is schematically depicted as a single block. A signal indicating the number of rotations measured by the wheel speed sensor 201 is input to the vehicle control device 10. The vehicle control device 10 can grasp the traveling speed of the vehicle 100 based on this signal.

[0033] The acceleration sensor 202 is a sensor for detecting the acceleration of the vehicle 100. The acceleration sensor 202 is attached to the vehicle body 101. The acceleration sensor 202 is configured as a six-axis acceleration sensor that can detect not only the acceleration in the front-rear direction, the left-right direction, and the up-down direction of the vehicle body 101, but also the rotational accelerations of pitching, rolling, and yawing.

[0034] The acceleration acquired by the acceleration sensor 202 includes an acceleration GX along the traveling direction of the vehicle 100 (i.e., the longitudinal direction) and an acceleration Gy along the lateral direction of the vehicle 100. The acceleration GX is also called "longitudinal acceleration," and the acceleration G is also called "lateral acceleration." Both of these are acquired as numerical values ​​in units of "G," which is the acceleration due to gravity, such as "0.5G." Signals indicating the respective accelerations detected by the acceleration sensor 202 are input to the vehicle control device 10.

[0035] The current sensor 203 is a sensor for detecting the value of the driving current flowing through the rotating electric machine 150. A signal indicating the value of the driving current detected by the current sensor 203 is input to the vehicle control device 10. The vehicle control device 10 can determine the magnitude of the driving force generated by the rotating electric machine 150 based on the value of the input driving current.

[0036] The exterior camera 204 is a camera that captures images of the surroundings of the vehicle 100, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) camera. Image data captured by the exterior camera 204 is input to the vehicle control device 10. By processing the images, the vehicle control device 10 can determine the presence or absence of obstacles (for example, steps such as wheel chocks) around the vehicle 100 and their shapes.

[0037] Note that vehicle 100 may be equipped with other sensors in addition to exterior camera 204 or instead of exterior camera 204 as sensors for detecting the conditions around vehicle 100. Such sensors include, for example, a LIDAR (Light Detection And Ranging) sensor, radar, etc.

[0038] The accelerator sensor 205 is a sensor that detects the amount of accelerator pedal operation, i.e., the accelerator opening degree. A signal indicating the amount of accelerator pedal operation detected by the accelerator sensor 205 is input to the vehicle control device 10.

[0039] The external temperature sensor 206 is a sensor that detects the temperature outside the vehicle 100. A signal indicating the external temperature detected by the external temperature sensor 206 is input to the vehicle control device 10.

[0040] The gradient sensor 207 is a sensor that detects the gradient of the road surface on which the vehicle 100 is traveling. A signal (detected value) indicating the value of the gradient detected by the gradient sensor 207 is input to the vehicle control device 10.

[0041] The brake sensor 208 is a sensor that detects the brake hydraulic pressure of the brake devices 131 and 132. A signal indicating the brake hydraulic pressure detected by the brake sensor 208 is input to the vehicle control device 10.

[0042] The parking sensor 209 is a sensor that detects the on / off state of the parking brake of the vehicle 100. A signal indicating the on / off state detected by the parking sensor 209 is input to the vehicle control device 10.

[0043] The yaw rate sensor 210 is a sensor for detecting the yaw rate of the vehicle 100. A signal indicating the yaw rate detected by the yaw rate sensor 210 is input to the vehicle control device .

[0044] The rotation speed sensor 211 is a sensor for detecting the rotation angle and rotation speed of the rotating electric machine 150. A signal indicating the rotation speed detected by the rotation speed sensor 211 is input to the vehicle control device 10.

[0045] The cooling sensor 212 is a sensor for detecting the temperature of the cooling water that cools the drive unit 152. The drive unit 152 may include a rotating electric machine 150 and an inverter 151. The cooling water cools the inverter 151, for example. A signal indicating the temperature detected by the cooling sensor 212 is input to the vehicle control device 10.

[0046] 5 is a diagram showing an example of the configuration of a driving unit 152 including a rotating electric machine 150 and an inverter 151. The rotating electric machine 150 includes a stator 153, a rotor 154, a current sensor 203, and a rotation speed sensor 211. The rotating electric machine 150 is a three-phase motor generator, and the stator 153 has windings 155U, 155V, and 155W of multiple phases. The winding 155U is a U-phase winding, the winding 155V is a V-phase winding, and the winding 155W is a W-phase winding. As an example, the current sensor 203 detects the current flowing through the winding 155V and the current flowing through the winding 155W. The rotation speed sensor 211 is, for example, a resolver, and detects the rotation angle and rotation speed of the rotor 154.

[0047] Inverter 151 has six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd. Hereinafter, when there is no need to distinguish between the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd, the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd will each be referred to as a "power element 156." Each power element 156 is, for example, a power transistor. Power elements 156Uu and 156Ud are U-phase power elements, power elements 156Vu and 156Vd are V-phase power elements, and power elements 156Wu and 156Wd are W-phase power elements. Power elements 156Uu and 156Ud are bridge-connected to winding 155U, power elements 156Vu and 156Vd are bridge-connected to winding 155V, and power elements 156Wu and 156Wd are bridge-connected to winding 155W.

[0048] The inverter 151 has one temperature sensor 157. The temperature sensor 157 is provided in one of the power elements 156. In the present embodiment, as an example, the temperature sensor 157 is provided in the power element 156Vu and detects the temperature of the power element 156Vu. Note that although the example in which the temperature sensor 157 is provided in the power element 156Vu is given here, the temperature sensor 157 may be provided in a power element 156 other than the power element 156Vu. Furthermore, the temperature sensor 157 may be provided in the power element 156 with the strictest heat resistance conditions among the six power elements 156. For example, if the inverter 151 has a heat dissipation mechanism, the power element 156 with the strictest heat resistance conditions corresponds to the power element with the smallest heat dissipation energy by the heat dissipation mechanism. These power elements may be interpreted as inverter elements.

[0049] Next, an example of the functional configuration of the CPU 21A of the vehicle control device 10 will be described with reference to Fig. 4. Fig. 4 is a block diagram showing an example of the functional configuration of the CPU 21A of the vehicle control device 10. The CPU 21A functions as each functional unit shown in Fig. 4 by reading and executing a vehicle control program 23A stored in the storage unit 23 (see Fig. 2). The CPU 21A includes a control unit 31 and an inverter control unit 32.

[0050] The control unit 31 controls the target torque of the rotating electrical machine 150 (see FIG. 1) based on the detection information of the sensor group 200. The control unit 31 may include a first torque control unit 31a that controls a target torque (TACC) according to the accelerator opening, a second torque control unit 31b, and a target torque selection unit 31c.

[0051] First torque control unit 31a may calculate accelerator target torque TACC based on a signal indicating the accelerator pedal operation amount from accelerator sensor 205. Accelerator target torque TACC may be interpreted as the accelerator opening, that is, the torque according to the driver's intention.

[0052] The second torque control unit 31b may calculate the TRC target torque TTRC based on the detected value (gradient value) detected by the gradient sensor 207 and the wheel speed. The wheel speed may include the speed of both the driving wheels and the driven wheels. The TRC target torque TTRC may be interpreted as a torque that stably transmits the driving force to the road surface by suppressing slip of the driving wheels.

[0053] (Control Example 1 by Second Torque Control Unit 31b) When the gradient of the road surface on which the vehicle 100 is located tends to increase, the second torque control unit 31b executes control to advance the timing to start suppressing torque of the prime mover so as to suppress slippage of the drive wheels of the vehicle 100 when the vehicle 100 starts moving. Specifically, on an uphill road with a steep gradient, the vehicle control device 10 calculates the amount of slip change using differential control and suppresses the torque when the vehicle 100 starts moving when even a slight slip occurs. In other words, the vehicle control device 10 executes control to advance the timing to start suppressing torque of the prime mover. By advancing the timing to start torque suppression, it is possible to suppress a decrease in the coefficient of friction μ of the road surface, i.e., the snow surface, caused by melting snow during rotation of the drive wheels due to initial slippage. This makes it possible to suppress getting stuck when going uphill.

[0054] Furthermore, when the gradient of the road surface on which the vehicle 100 is located tends to decrease, the vehicle control device 10 delays the timing at which the torque suppression of the prime mover is initiated so as to allow suppression of slip of the drive wheels of the vehicle 100 for a certain period of time when the vehicle 100 starts moving. Specifically, on a flat road with a small gradient, the vehicle control device 10 accumulates the amount of slip by proportional control and allows initial slip until the amount of slip reaches, for example, about 20 kph. In other words, the vehicle control device 10 executes control to delay the timing at which the torque suppression of the prime mover is initiated. By allowing a certain amount of slip of the drive wheels when the vehicle 100 starts moving, the driver of the vehicle 100 can be made aware that slip has occurred. This allows the driver to recognize that the road surface is prone to slipping due to icy conditions, etc., and to drive carefully.

[0055] (Control Example 2 by Second Torque Control Unit 31b) The second torque control unit 31b controls the timing to start torque suppression based on the amount of slip of the drive wheels and the gradient value. By using the amount of slip of the drive wheels and the gradient value, the amount of slip can be integrated through proportional control on flat roads with a small gradient. This allows drive wheel slip to be tolerated for a certain period of time when the vehicle 100 starts moving, so that a certain amount of initial slip can be tolerated as a warning to encourage safe driving.

[0056] (Control Example 3 by Second Torque Control Unit 31b) The second torque control unit 31b controls the timing to start torque suppression based on the slip change amount of the drive wheels and the gradient value. By using the slip change amount of the drive wheels and the gradient value, the slip change amount can be calculated by differential control on an uphill road with a steep gradient. This prevents the vehicle 100 from being unable to climb the slope and becoming stuck on the road.

[0057] (Control Example 4 by Second Torque Control Unit 31b) The second torque control unit 31b sets a first timing for starting torque suppression when the gradient value of the road surface that is an uphill road is a first value earlier than a second timing for starting torque suppression when the gradient value of the road surface that is an uphill road is a second value that is smaller than the first value. By changing the timing for starting torque suppression according to a specific value that indicates the gradient of the road surface, it is possible, with a simple configuration, to both make the driver of the vehicle 100 aware that a slip has occurred and prevent the vehicle 100 from getting stuck.

[0058] (Control Example 5 by Second Torque Control Unit 31b) The second torque control unit 31b determines the amount of slip change based on the difference between the amount of change in speed of the drive wheels and the amount of change in speed of the vehicle 100, and uses a value detected by a sensor that measures acceleration as the amount of change in speed of the vehicle 100. This makes it possible to estimate the amount of change in speed of the drive wheels and the amount of change in speed of the vehicle 100 using a general-purpose sensor mounted on the vehicle 100, without having to mount a dedicated sensor on the vehicle 100 for adjusting the timing to start torque suppression.

[0059] (Control Example 6 by Second Torque Control Unit 31b) The second torque control unit 31b sets a value calculated from the required torque r×Wsin (where r is the radius of the drive wheels and W is the weight of the vehicle 100) according to the gradient as the lower limit of the torque to be generated by the prime mover when torque suppression is started. This makes it possible to prevent the vehicle 100 from getting stuck while taking into consideration the minimum torque required for the vehicle 100 to climb a slope against gravity when climbing an uphill slope.

[0060] The target torque selection unit 31c selects either the TRC target torque TTRC or the accelerator target torque TACC as the target torque, and may output the selected target torque as the MG target torque TMG for vector control.

[0061] The inverter control unit 32 controls the inverter 151 that drives the rotary electric machine 150. Specifically, the vector control unit 32c executes torque control that matches the MG target torque TMG, which is the value of the command torque.

[0062] Next, the operation of the vehicle control device 10 will be described with reference to FIGS. 6A to 9B.

[0063] 6A and 6B are flowcharts for explaining the slip prevention process by the vehicle control device 10. FIGS. 7A, 7B, 8A, and 8B are diagrams for explaining the slip prevention process by the vehicle control device 10.

[0064] For example, when the accelerator pedal is depressed, the slip suppression process shown in Fig. 6A is initiated. In step S1, the vehicle control device 10 calculates the driving wheel speed Vw and the driven wheel speed Vb according to equation (1).

[0065] (Number 1) Vw=(Vwl+Vwr) / 2 Vb = (Vl + Vr) / 2 (@2WD) or Vb = previous Vb value + G sensor detection value (@4WD) (1)

[0066] The driving wheel speed Vw may be interpreted as the average value of the respective rotational speeds of the wheels 121 and 122 which are the driving wheels shown in FIG. 1. In the present disclosure, since what can be controlled by the rotary electric machine 150 is the torque transmitted to the left and right wheels, the average value of the rotational speeds at the time of slip of each of the left and right driving wheels is used as the driving wheel speed V* (see FIG. 8A) to be controlled.

[0067] The driven wheel speed Vb may typically be interpreted as the moving speed of the vehicle body 101 shown in FIG. 1, and specifically, may be interpreted as the average value of the respective rotational speeds of the wheels 111 and 112 which are the driven wheels of the two-wheel drive vehicle as shown in FIG. 1. Note that the driven wheel speed Vb of the four-wheel drive vehicle may be interpreted as a value obtained by adding the detection value of a G sensor or the like to the previous value of the driven wheel speed Vb.

[0068] In step S2, the vehicle control device 10 calculates the difference between the driving wheel speed Vw and the driven wheel speed Vb. Further, the vehicle control device 10 compares the difference with the slip amount suppression start threshold value KS. The slip amount suppression start threshold value KS may be interpreted as a threshold value whose value decreases in proportion to the road surface gradient as the road surface gradient increases, for example, as shown in FIG. 7A. FIG. 7A shows two slip amount suppression start threshold values KS with different friction coefficient μ values.

[0069] As a result of the comparison, when the difference is greater than or equal to the slip amount suppression start threshold value KS (≧KS) (step S2: YES), the vehicle control device 10 executes the process of step S3. When the difference is less than the slip amount suppression start threshold value KS (<KS) (step S2: NO), the vehicle control device 10 executes the process of step S4.

[0070] In step S3, the vehicle control device 10 sets the slip control execution flag Xslip to 1 and executes the process of step S4.

[0071] In step S4, the vehicle control device 10 calculates the driving wheel speed change amount ΔVw and the driven wheel speed change amount ΔVb according to equation (2).

[0072] (Number 2) ΔVw=Vw-Vw previous value ΔVb = Vb - Vb previous value (@2WD) Or, ΔVb = G sensor detection value (@4WD) (2)

[0073] The drive wheel speed change amount ΔVw may be interpreted as the difference between the current value of the drive wheel speed Vw and the previous value of the drive wheel speed Vw. The driven wheel speed change amount ΔVb of a two-wheel drive vehicle may be interpreted as the difference between the current value of the driven wheel speed Vb and the previous value of the driven wheel speed Vb. The driven wheel speed change amount ΔVb of a four-wheel drive vehicle may be interpreted as a detection value of a G sensor or the like.

[0074] In step S5, the vehicle control device 10 calculates the difference between the driving wheel speed change amount ΔVw and the driven wheel speed change amount ΔVb, and compares this difference with the slip change amount suppression start threshold KSD.

[0075] As shown in FIG. 7B, the slip change suppression start threshold KSD is set to a value that makes it easy to start slip suppression control even if the differential deviation is small when the road surface gradient is large, and makes it difficult to start slip suppression control when the road surface gradient is small.

[0076] In the example of Figure 7B, in Section A, where the road surface gradient is small enough to be considered flat, the slip change suppression start threshold KSD is high, making it difficult for slip suppression to begin using derivative control. As the road surface gradient increases beyond Section A, the slip change suppression start threshold KSD decreases in proportion to the road surface gradient. Furthermore, in Section B, where the road surface gradient is large enough to be considered a slope, the slip change suppression start threshold KSD is low, so slip suppression begins immediately using derivative control. Note that Figure 7B shows two slip change suppression start threshold KSD values ​​for different values ​​of the friction coefficient μ.

[0077] When the vehicle control device 10 determines, as a result of comparison, that the difference is greater than or equal to the slip change amount suppression start threshold KSD (≧KSD) (step S5: YES), it executes the process of step S6. When the difference is less than the slip change amount suppression start threshold KSD (<KSD) (step S5: NO), it executes the process of step S7 (see FIG. 6B).

[0078] In step S6, when the slip control execution flag Xslip is set to 1 in the process of step S3, for example, the vehicle control device 10 maintains the value. On the other hand, when the difference between the driving wheel speed Vw and the driven wheel speed Vb is less than the slip amount suppression start threshold KS (<KS) in the process of step S2, that is, when the slip control execution flag Xslip is set to 0 in the process of step S3, the vehicle control device 10 sets the slip control execution flag Xslip to 1 instead of 0.

[0079] In step S7 shown in FIG. 6B, the vehicle control device 10 determines whether the slip control execution flag Xslip is 0 or 1. When the slip control execution flag Xslip is 0 (step S7: NO), the vehicle control device 10 executes the processes after step S1.

[0080] When the slip control execution flag Xslip is 1 (step S7: YES), the vehicle control device 10 executes the process of step S8. In step S8, the vehicle control device 10 calculates the target driving wheel speed Vcmd (see FIG. 8A) according to equation (3). The 1.03 in equation (3) is the speed corresponding to 3% of the driven wheel speed Vb. Either the speed corresponding to 3% of the driven wheel speed Vb or 2 kph may be set for the target driving wheel speed Vcmd. This can achieve both running stability and acceleration performance.

[0081] (Equation 3) Vcmd = MAX(Vb × 1.03, 2 kph) ··· (3)

[0082] Next, in step S9, the vehicle control device 10 sets the slip torque Ts according to equation (4). The slip torque Ts may be interpreted as a torque for suppressing slip. The vehicle control device 10 sets the slip torque Ts by executing PID_FB control so that the actual drive wheel speed Vw becomes equal to the target drive wheel speed Vcmd. Kp represents the proportional gain, Ki represents the integral gain, Kd represents the differential gain, and e represents the deviation. The deviation e is calculated by e = Vcmd - Vb.

[0083] (Number 4) Ts=Kp×e+Ki×∫e+Kd×Δe Upper limit > Ts > lower limit (4)

[0084] In step S10, the vehicle control device 10 compares the slip torque Ts with a specific value. The specific value may be interpreted as the minimum torque required for the vehicle 100 to climb a slope against gravity when climbing. Specifically, the specific value may be interpreted as a value calculated by r × W sin θ, where r is the tire radius, W is the vehicle weight, and θ is the road gradient.

[0085] If the slip torque Ts is less than or equal to a specific value (≦r×Wsinθ) (step S10: YES), the vehicle control device 10 executes the processing of step S11, and if the slip torque Ts exceeds a specific value (>r×Wsinθ) (step S10: NO), the vehicle control device 10 executes the processing of step S12.

[0086] In step S11, the vehicle control device 10 sets a specific value (r×W sin θ) to the slip torque Ts.

[0087] In step S12, the vehicle control device 10 determines whether the previous value of the slip control execution flag Xslip is 0 or 1.

[0088] If the previous value of the slip control execution flag Xslip is 0 (step S12: YES), the vehicle control device 10 executes the process of step S13. If the previous value of the slip control execution flag Xslip is 1 (step S12: NO), the vehicle control device 10 executes the process of step S14.

[0089] In step S13, the vehicle control device 10 sets an initial value of the slip torque Ts. The initial value of the slip torque Ts may be interpreted as the slip torque Ts (see FIG. 8A) when the slip control execution flag Xslip changes from 0 to 1. For example, the initial value of the slip torque Ts may be set to a slip limit torque TsMAX corresponding to the maximum friction coefficient μp of the road surface (see FIG. 8B).

[0090] The maximum friction coefficient μp of the road surface may be estimated by, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2024-18458. Specifically, the vehicle control device 10 may sort the combined data of the slip ratio s and the friction coefficient μ calculated at the same timing as the slip ratio into selected data or non-selected data, and estimate the maximum friction coefficient μp, which is the maximum value of the friction coefficient μ, using the multiple selected data.

[0091] Next, in step S14, the vehicle control device 10 compares the slip torque Ts with the accelerator torque demand Ta. If the slip torque Ts exceeds the accelerator torque demand Ta (Ts>Ta) (step S14: YES), the vehicle control device 10 executes the process of step S16.

[0092] If the slip torque Ts is equal to or less than the accelerator torque request Ta (Ts≦Ta) (step S14: NO), the vehicle control device 10 executes the process of step S15 to perform slip suppression control.

[0093] In step S15, the vehicle control device 10 compares the absolute value of the difference between the driving wheel speed Vw and the driven wheel speed Vb with a specific speed.

[0094] If the difference remains below 0 kph (≦0 kph) for one second (step S15: YES), the vehicle control device 10 determines that the slip has subsided and executes the process of step S16.

[0095] If the difference exceeds 0 kph (>0 kph) within, for example, one second, the vehicle control device 10 determines that the slip has not converged, and repeats the processes from step S1 onwards without executing the process of step S16.

[0096] In step S16, the vehicle control device 10 sets the slip control execution flag Xslip to 0, thereby ending the slip suppression control, and repeats the processing from step S1 onwards.

[0097] 9A and 9B are diagrams for explaining torque suppression control according to the present disclosure when initial slip occurs.

[0098] Figure 9A shows a timing chart for when, for example, when a vehicle 100 on a slope in snowy conditions starts uphill, control is executed to advance the timing of torque suppression (torque suppression control) in order to prevent the drive wheels from initially slipping and getting stuck.

[0099] 9A shows, from top to bottom, the rotational speed (= drive wheel speed Vw), slip amount, slip change amount, and torque. On an uphill road with a steep road gradient, the vehicle control device 10 calculates the slip change amount using differential control and suppresses the torque at the start of the vehicle 100 when even a slight slip occurs. The vehicle control device 10 starts torque suppression, for example, at time t1 shown in FIG. 9A. In other words, the vehicle control device 10 advances the timing at which torque suppression of the rotating electric machine 150 starts. By advancing the timing at which torque suppression starts, it is possible to prevent snow or the like from melting during rotation of the drive wheels due to initial slip, thereby suppressing a decrease in the friction coefficient μ of the road surface, i.e., the snow surface.

[0100] FIG. 9B shows a timing chart of a case where torque suppression control is executed with priority given to making the driver of the vehicle 100 aware of the occurrence of slippage when the vehicle 100, which is present on a flat road where there is no risk of getting stuck, starts on the flat road. FIG. 9B shows, from top to bottom, rotational speed (= drive wheel speed), slip amount, slip change amount, and torque. On a flat road with a small road gradient, the vehicle control device 10 accumulates the slip amount using proportional control and allows initial slippage until the slip amount reaches, for example, approximately 20 kph. In other words, the vehicle control device 10 executes control to delay the timing for starting torque suppression of the rotating electric machine 150. The vehicle control device 10 starts torque suppression, for example, at time t2 shown in FIG. 9B. By allowing the drive wheels to slip for a certain period of time when the vehicle 100 starts, the driver of the vehicle 100 can be made aware of the occurrence of slippage.

[0101] In this way, the vehicle control device 10 advances the timing to start torque suppression so as to suppress slip when the gradient of the road surface on which the vehicle 100 is located tends to increase. Furthermore, when the gradient of the road surface on which the vehicle 100 is located tends to decrease, the vehicle control device 10 allows slip suppression for a certain period of time before starting torque suppression.

[0102] Although the present embodiment has been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present disclosure.

[0103] Furthermore, the configuration of the vehicle control device 10 described in the above embodiment (see Figure 2) is an example, and it goes without saying that unnecessary parts may be deleted or new parts may be added within the scope of the present disclosure.

[0104] Furthermore, the processing flow of the vehicle control program 23A described in the above embodiment is also an example, and it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged within the scope of the present disclosure.

[0105] The controller and methods described herein may be implemented by a special-purpose computer having a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by a special-purpose computer having a processor configured with dedicated hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0106] Note that the vehicle 100 of the present disclosure is not limited to an electric vehicle. For example, the vehicle 100 may be a hybrid vehicle equipped with an internal combustion engine in addition to the rotating electric machine 150, or may be a conventional engine vehicle equipped with only an internal combustion engine instead of the rotating electric machine 150. The internal combustion engine may be interpreted as a prime mover of the present disclosure that generates torque for driving the vehicle. When the vehicle 100 equipped with an internal combustion engine is equipped with the vehicle control device 10 of the present disclosure, the vehicle control device 10 advances the timing to start suppressing the torque generated by the internal combustion engine so as to suppress slip of the drive wheels when the vehicle 100 starts to move if the gradient of the road surface tends to increase. Furthermore, the vehicle control device 10 may delay the timing to start suppressing the torque generated by the internal combustion engine so as to allow suppression of slip of the drive wheels when the vehicle 100 starts to move if the gradient of the road surface tends to decrease.

[0107] In addition, since the rotating electric machine 150 as a prime mover generates torque immediately in response to accelerator operation, even slight accelerator operation can easily induce slippage due to torque fluctuations. By applying the vehicle control device 10 of the present disclosure to the vehicle 100 equipped with the rotating electric machine 150, it is possible to suppress slippage in the initial stage of rise in drive wheel speed even in response to slight accelerator operation, so that the driver can smoothly start the vehicle 100 uphill on a low μ road surface without getting stuck, even without delicate accelerator operation.

[0108] The present invention is also applicable to program products.

[0109] The following notes are provided regarding the technology of the present disclosure.

[0110] (Appendix 1) an inverter control unit (32) for controlling an inverter (151) for driving a prime mover (150) for driving the vehicle (100); a control unit (31) that, when a gradient of a road surface on which the vehicle is located tends to increase, executes control to advance a timing for starting torque suppression of the prime mover so as to suppress slip of a drive wheel of the vehicle when the vehicle starts moving; A vehicle control device (10) comprising:

[0111] (Appendix 2) 2. The vehicle control device according to claim 1, wherein the control unit controls the timing to start the torque suppression based on the amount of slip of the drive wheels and the value of the gradient.

[0112] (Appendix 3) 2. The vehicle control device according to claim 1, wherein the control unit controls the timing to start the torque suppression based on a slip change amount of the drive wheels and a value of the gradient.

[0113] (Appendix 4) The vehicle control device described in Appendix 3, wherein the control unit sets a first timing for starting the torque suppression when the gradient value of the road surface, which is an uphill road, is a first value earlier than a second timing for starting the torque suppression when the gradient value of the road surface, which is an uphill road, is a second value smaller than the first value.

[0114] (Appendix 5) The vehicle control device described in Appendix 4, wherein the control unit determines the amount of slip change based on the difference between the amount of speed change of the drive wheels and the amount of speed change of the vehicle, and uses a value detected by a sensor that measures acceleration as the amount of speed change of the vehicle.

[0115] (Appendix 6) The vehicle control device described in Appendix 1, wherein the control unit sets a value calculated from the required torque r x Wsin (where r is the radius of the drive wheel and W is the weight of the vehicle) according to the gradient as the lower limit value of the torque generated by the prime mover when starting the torque suppression.

[0116] (Appendix 7) At least one processor (21A) Controlling an inverter (151) that drives a prime mover (150) for driving the vehicle (100), When the gradient of the road surface on which the vehicle is located tends to increase, the timing to start torque suppression of the rotary electric machine is advanced so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving. A vehicle control program (23A) for executing a process including the above.

[0117] (Appendix 8) At least one processor (21A) Controlling an inverter (151) that drives a prime mover (150) for driving the vehicle (100), When the gradient of the road surface on which the vehicle is located tends to increase, the timing to start suppressing the torque of the prime mover is advanced so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving. A vehicle control method that executes a process including the steps of:

[0118] (Appendix 9) At least one processor (21A) Controlling an inverter (151) that drives a prime mover (150) for driving the vehicle (100), When the gradient of the road surface on which the vehicle is located tends to increase, the timing to start suppressing the torque of the prime mover is advanced so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving. A computer program product including a program for causing a process to be performed, including [Explanation of symbols]

[0119] 10 Vehicle control device 20 Brake ECU 21 Control Unit 21A CPU 21B ROM 21C RAM 21D Input / Output Interface 21E Bus 22 Communications Department 23 Memory section 23A Vehicle Control Program 31 Control Unit 31a First torque control section 31b Second torque control section 31c Target torque selection section 32 Inverter control unit 32c Vector control unit 100 vehicles 101 Body 111 Wheels 112 Wheels 121 Wheels 122 Wheels 131 Brake equipment 132 Brake equipment 140 Powertrain Section 150 Rotating Electric Machine 151 Inverter 152 Drive unit 153 Stator 154 Rotor 155U winding 155V winding 155W winding 156 Power Elements 156 each power element 156Uu power element 156Vu power element 156Wu power element 157 Temperature Sensor 160 batteries 200 sensors 201 Wheel speed sensor 202 Acceleration Sensor 203 Current Sensor 204 Exterior Camera 205 Accelerator sensor 206 External temperature sensor 207 Gradient Sensor 208 Brake sensor 209 Parking Sensor 210 Yaw rate sensor 211 RPM sensor 212 Cooling Sensor

Claims

1. an inverter control unit (32) for controlling an inverter (151) for driving a prime mover (150) for driving the vehicle (100) mounted on the vehicle; a control unit (31) that, when the gradient of a road surface on which the vehicle is located tends to increase, executes control to advance the timing of starting torque suppression of the prime mover so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving; A vehicle control device (10) comprising:

2. The vehicle control device according to claim 1 , wherein the control unit controls the timing to start the torque suppression based on the amount of slip of the drive wheels and the value of the gradient.

3. The vehicle control device according to claim 1 , wherein the control unit controls the timing to start the torque suppression based on the amount of slip change of the drive wheels and the value of the gradient.

4. 4. The vehicle control device according to claim 3, wherein the control unit sets a first timing for starting the torque suppression when the gradient value of the road surface that is an uphill road is a first value earlier than a second timing for starting the torque suppression when the gradient value of the road surface that is an uphill road is a second value that is smaller than the first value.

5. 5. The vehicle control device according to claim 4, wherein the control unit determines the amount of slip change based on a difference between an amount of change in speed of the drive wheels and an amount of change in speed of the vehicle, and uses a value detected by a sensor that measures acceleration as the amount of change in speed of the vehicle.

6. 2. The vehicle control device according to claim 1, wherein the control unit sets a value calculated from a required torque r × W sin (where r is a radius of the drive wheels and W is a weight of the vehicle) corresponding to the gradient as a lower limit value of the torque generated by the prime mover when the torque suppression is started.

7. At least one processor (21A) Controlling an inverter (151) that drives a prime mover (150) for driving the vehicle (100), When the gradient of the road surface on which the vehicle is located tends to increase, the timing to start torque suppression of the rotary electric machine is advanced so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving. A vehicle control program (23A) for executing a process including the above.

8. At least one processor (21A) Controlling an inverter (151) that drives a prime mover (150) for driving the vehicle (100), When the gradient of the road surface on which the vehicle is located tends to increase, the timing to start suppressing the torque of the prime mover is advanced so as to suppress slip of the drive wheels of the vehicle when the vehicle starts moving. A vehicle control method that executes a process including the steps of:

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