Vehicle control device and vehicle control method

Abstract

A vehicle control device according to one embodiment of the present disclosure comprises a control unit that can derive a target torque by adding a fluctuation torque fluctuating periodically to a request torque according to an acceleration request and control the torque of a motor on the basis of the derived target torque. The control unit can change at least one of the fluctuation range, frequency, and waveform of the fluctuation torque on the basis of any of a vehicle speed, a longitudinal acceleration, a vehicle body slip angular velocity, a self-aligning torque, a road friction coefficient, a turning state, and a vehicle tire torsional resonance frequency.

Description

Technical Field

[0001] The present disclosure relates to a vehicle control device and a vehicle control method mounted on a vehicle.

Background Art

[0002] Conventionally, various technologies for operating a vehicle more safely have been proposed (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] <0OO0033>A vehicle control device according to an embodiment of the present disclosure is a device that controls a vehicle that travels by motor drive. This vehicle control device includes a control unit capable of deriving a target torque by adding a fluctuating torque that periodically fluctuates to a required torque according to an acceleration requirement, and controlling the torque of the motor based on the derived target torque. This control unit is In order to make the driver aware of the possibility of the vehicle slipping, configured to be able to change at least one of the fluctuation width, period, and waveform of the fluctuating torque based on any one of the vehicle speed, longitudinal and lateral acceleration, body slip angular velocity, self-aligning torque, road surface friction coefficient, turning state, and torsional resonance frequency of the vehicle tires. This control unit can adjust the period of the fluctuating torque to be closer to or further away from the reciprocal of the torsional resonance frequency of the tires installed on the vehicle, based on one of the following: vehicle speed, longitudinal acceleration, vehicle slip angular velocity, self-aligning torque, road surface friction coefficient, or turning condition.

[0005] A vehicle control method according to an embodiment of the present disclosure is a method for controlling a vehicle that travels by motor drive. This vehicle control method includes the following 3 steps. (A) Deriving a target torque by adding a fluctuating torque that periodically fluctuates to a required torque according to an acceleration requirement, and controlling the torque of the motor based on the derived target torque (B) In order to make the driver aware of the possibility of the vehicle slipping, To modify at least one of the fluctuation range, period, and waveform of the fluctuating torque based on any of the following: vehicle speed, longitudinal acceleration, vehicle slip angular velocity, self-aligning torque, road surface friction coefficient, turning condition, and the torsional resonance frequency of the vehicle's tires. (C) Based on any of the vehicle's speed, longitudinal acceleration, vehicle slip angular velocity, self-aligning torque, road surface friction coefficient, and turning condition, the period of the fluctuating torque is brought closer to or further away from the reciprocal of the torsional resonance frequency of the tires installed on the vehicle. [Brief explanation of the drawing]

[0006] The accompanying drawings are provided for further understanding of this disclosure and are incorporated herein and constitute part of this specification. The drawings illustrate one embodiment and, together with the specification, serve to illustrate the principles of this disclosure.

[0007] [Figure 1] Figure 1 is a diagram showing an example of a functional block of a vehicle equipped with a vehicle control unit according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a diagram illustrating an example of the procedure for deriving the target torque in the drive control unit shown in Figure 1. [Figure 3] Figure 3 is a diagram illustrating an example of the procedure for deriving the fluctuating torque in step S104 of Figure 2. [Figure 4] Figure 4(A) shows an example of the waveform of the required torque. Figure 4(B) shows an example of the waveform of the fluctuating torque. Figure 4(C) shows an example of the waveform of the target torque. [Figure 5] Figure 5(A) shows an example of the waveform of the required torque. Figure 5(B) shows an example of the waveform of the fluctuating torque. Figure 5(C) shows an example of the waveform of the target torque. [Figure 6] Figure 6 is a diagram illustrating one modified example of the procedure for deriving the fluctuating torque in step S104 of Figure 2. [Figure 7] Figure 7 is a diagram illustrating a modified example of the procedure for deriving the fluctuating torque in step S104 of Figure 2. [Figure 8]FIG. 8 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 9] FIG. 9 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 10] FIG. 10 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 11] FIG. 11 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 12] FIG. 12 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 13] FIG. 13 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 14] FIG. 14(A) is a diagram showing an example of the waveform of the required torque. FIG. 14(B) is a diagram showing an example of the waveform of the fluctuating torque. FIG. 14(C) is a diagram showing an example of the waveform of the target torque. [Figure 15] FIG. 15 is a diagram showing a modified example of the functional block of the vehicle in FIG. 1. [Figure 16] FIG. 16 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 17] FIG. 17 is a diagram for explaining a modified example of the procedure for deriving the fluctuating torque in step S104 of FIG. 2. [Figure 18] FIG. 18 is a diagram showing a schematic configuration example of a vehicle control system according to an application example of the present disclosure. [Figure 19] FIG. 19 is a diagram showing an example of the functional block of the vehicle in FIG. 18. [Figure 20] FIG. 20 is a diagram showing an example of the functional block of the server device in FIG. 18.

MODE FOR CARRYING OUT THE INVENTION

[0008] In a vehicle that travels by motor drive, since the motor output is smoother than the engine output, it is difficult for the driver to grasp the slip of the vehicle. Therefore, there are cases where the driver fails to notice the possibility of the vehicle slipping, and the vehicle is exposed to danger. It is desirable to provide a vehicle control device and a vehicle control method that can make the driver aware of the possibility of the vehicle slipping.

[0009] Hereinafter, several exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following description shows a specific example of the present disclosure and should not be construed as limiting the present disclosure. For example, each element including numerical values, shapes, materials, parts, the positions of each part, and the connection method of each part is merely an example and should not be construed as limiting the present disclosure. Also, in the following exemplary embodiments, components not described in the independent claims based on the highest concept of the present disclosure are optional and may be provided as necessary. The drawings are schematic and are not intended to be drawn to actual size. Throughout this specification and the drawings, components having substantially the same function and substantially the same configuration are denoted by the same reference numerals, and redundant descriptions are omitted. Also, components not directly related to one embodiment of the present disclosure are not shown in the drawings.

[0010] <1. Embodiment> [Configuration Example] FIG. 1 shows a schematic configuration example of a vehicle 1 including a control unit 20 according to an embodiment of the present disclosure. The control unit 20 corresponds to a specific example of the "control unit" of the present disclosure. The vehicle 1 is capable of traveling by motor drive. The vehicle 1 includes, for example, as shown in FIG. 1, a sensor unit 10, a control unit 20, and a motor 30.

[0011] The sensor unit 10 is composed of various sensors mounted on the vehicle 1. For example, as shown in Figure 1, the sensor unit 10 is composed of an accelerator opening sensor 11, a vehicle speed sensor 12, an acceleration sensor 13, an angular velocity sensor 14, a steering angle sensor 15, a steering torque sensor 16, and a road surface friction coefficient sensor 17. The sensor unit 10 may also include sensors other than those listed above.

[0012] The accelerator pedal position sensor 11 is capable of detecting the accelerator pedal position from the amount the accelerator pedal is pressed. The accelerator pedal position sensor 11 is also capable of outputting time-series data (accelerator pedal position data) of the detected accelerator pedal position to the control unit 20.

[0013] The vehicle speed sensor 12 is capable of detecting the speed of vehicle 1. The vehicle speed sensor 12 is capable of outputting time-series data (vehicle speed data) of the detected vehicle speed to the control unit 20. The acceleration sensor 13 is capable of detecting the acceleration applied to vehicle 1. The acceleration sensor 13 is capable of outputting time-series data (acceleration data) of the detected acceleration in three directions to the control unit 20. The angular velocity sensor 14 is capable of detecting the angular velocity of vehicle 1. The angular velocity sensor 14 is capable of outputting time-series data (angular velocity data) of the detected three angular velocities (yaw angular velocity, roll angular velocity, and pitch angular velocity) to the control unit 20.

[0014] The steering angle sensor 15 is capable of detecting the steering angle of the steering wheel of vehicle 1. The steering angle sensor 15 is capable of outputting time-series data (steering angle data) of the detected steering angle to the control unit 20. The steering torque sensor 16 is capable of detecting the steering torque generated by the driver's steering wheel operation. The steering torque sensor 16 is capable of outputting time-series data (steering torque data) of the detected steering torque to the control unit 20.

[0015] The road surface friction coefficient sensor 17 is capable of estimating, for example, the friction coefficient of the road surface in front of the vehicle 1. The road surface friction coefficient sensor 17 is composed of, for example, a camera that images the area in front of the vehicle 1, a temperature sensor (outside air temperature sensor, road surface temperature sensor), a near-infrared sensor, a laser light sensor (TOF (Time of Flight) sensor), and other non-contact sensors. The road surface friction coefficient sensor 17 is capable of estimating the road surface friction coefficient based on the detection results of the above-mentioned non-contact sensors. The road surface friction coefficient sensor 17 is capable of outputting time-series data (road surface friction coefficient data) about the road surface friction coefficient obtained by estimation to the control unit 20. The road surface friction coefficient sensor 17 may also be, for example, a road surface sensor that directly measures the road surface friction coefficient.

[0016] The control unit 20 is capable of controlling the entire vehicle 1. The control unit 20 is, for example, a so-called ECU (Electronic Control Unit) and is composed of, for example, one or more processors and one or more memories. The control unit 20 may also be composed of, for example, a CPU (Central Processing Unit). In this case, the control unit 20 is capable of controlling the entire vehicle 1 by, for example, executing a program stored in a memory unit.

[0017] The control unit 20 is capable of controlling the vehicle 1, which is driven by a motor. The control unit 20 includes, for example, a driving control unit 21, as shown in Figure 1. The driving control unit 21 is capable of controlling the driving of the vehicle 1 (for example, the torque of the motor 30). The driving control unit 21 includes, for example, a requested torque derivation unit 22, a fluctuating torque derivation unit 23, and a motor torque control unit 24, as shown in Figure 1.

[0018] The requested torque derivation unit 22 is capable of deriving the requested torque in response to acceleration requests. Acceleration requests refer to the depressing of the accelerator pedal or the variation in the amount of depressing of the accelerator pedal. Acceleration requests may be made by the driver during manual driving or by the driving control unit 21 during automatic driving. The requested torque derivation unit 22 is capable of deriving the amount of torque (requested torque) that the motor 30 should generate based on accelerator opening data obtained from the accelerator opening sensor 11.

[0019] The fluctuating torque derivation unit 23 is capable of deriving a periodically fluctuating torque. The fluctuating torque is intended to intentionally change the behavior of the vehicle 1, thereby alerting the driver to the possibility of vehicle 1 slippage. The fluctuating torque derivation unit 23 is capable of keeping the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque.

[0020] The fluctuating torque derivation unit 23 can change at least one of the fluctuation range, period, and waveform of the fluctuating torque based on vehicle speed data obtained from the vehicle speed sensor 12 installed on the vehicle 1. For example, the fluctuating torque derivation unit 23 can set the fluctuation range of the fluctuating torque to zero or a small value when the possibility of vehicle 1 slipping is low, and set the fluctuation range of the fluctuating torque to a large value when the possibility of vehicle 1 slipping is high. For example, the fluctuating torque derivation unit 23 can set the fluctuation period of the fluctuating torque to a large value when the possibility of vehicle 1 slipping is low, and set the fluctuation period of the fluctuating torque to a small value when the possibility of vehicle 1 slipping is high. For example, the fluctuating torque derivation unit 23 can set the waveform of the fluctuating torque to a smooth waveform (e.g., a sine wave) when the possibility of vehicle 1 slipping is low, and set the waveform of the fluctuating torque to a rectangular shape (e.g., a pulse shape) when the possibility of vehicle 1 slipping is high.

[0021] The motor torque control unit 24 derives a target torque by adding a variable torque to the requested torque, and is capable of controlling the torque of the motor 30 based on the derived target torque. The motor 30 is configured to drive the steering wheels of the vehicle 1 and drives the steering wheels of the vehicle 1 according to the target torque input from the motor torque control unit 24.

[0022] The control unit 20 further includes an electric power steering (EPS) control unit. The vehicle 1 further includes an EPS motor connected to the EPS control unit. The EPS motor is capable of adding steering assist torque to the steering shaft in response to a drive signal from the EPS control unit. The EPS control unit derives a steering assist torque that assists the steering torque generated by the driver's steering wheel operation, and sets the EPS torque corresponding to the derived steering assist torque. The EPS control unit outputs a control signal to the EPS motor so that the output torque of the EPS motor becomes the set EPS torque.

[0023] [Operation] Next, the operation of the travel control unit 21 will be explained with reference to Figure 2. Figure 2 is a diagram illustrating an example of the procedure for deriving the target torque.

[0024] The driving control unit 21 acquires an acceleration request from the accelerator pedal position sensor 11 (step S101). Next, when the driving control unit 21 acquires an acceleration request from the accelerator pedal position sensor 11 (step S102), if the acquired acceleration request is an acceleration or deceleration request (step S103; Y), it derives a fluctuating torque (step S104). If the acquired acceleration request is neither an acceleration nor a deceleration request (step S103; N), or if a fluctuating torque was derived in step S104, the driving control unit 21 derives a target torque (step S105). If the acquired acceleration request is neither an acceleration nor a deceleration request, the driving control unit 21 uses the requested torque corresponding to the acceleration request as the target torque. If a fluctuating torque was derived in step S104, the driving control unit 21 derives the target torque by adding a periodically fluctuating fluctuating torque to the requested torque corresponding to the acceleration request. The driving control unit 21 controls the torque of the motor 30 based on the derived target torque. At this time, the driving control unit 21 changes at least one of the fluctuation range, period, and waveform of the fluctuating torque based on the vehicle speed obtained from the vehicle speed sensor 12 provided on the vehicle 1. Furthermore, the driving control unit 21 keeps the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque.

[0025] Next, the method for deriving the fluctuating torque in step S104 will be described. Figure 3 shows an example of the procedure for deriving the fluctuating torque in step S104.

[0026] First, the driving control unit 21 acquires the vehicle speed v (vehicle speed data) from the vehicle speed sensor 12 (step S201). Next, if the vehicle speed v is 10 km / h (step S202; Y), the driving control unit 21 derives a variable torque corresponding to the vehicle speed v = 10 km / h (step S203). If the vehicle speed v is 100 km / h (step S202; N, step S204; Y), the driving control unit 21 derives a variable torque corresponding to the vehicle speed v = 100 km / h (step S205).

[0027] To derive the fluctuating torque, for example, a function with vehicle speed v as a variable can be used, or table data where the fluctuating torque is associated with each vehicle speed v can be used. The method for deriving the fluctuating torque is not limited to the method shown in Figure 3.

[0028] [effect] Next, the effects of the control unit 20 according to one embodiment of the present disclosure will be described.

[0029] In this embodiment, a target torque is derived by adding a periodically fluctuating torque to a required torque corresponding to an acceleration request, and the torque of the motor 30 is controlled based on the derived target torque. At this time, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the vehicle speed obtained from the vehicle speed sensor 12 provided on the vehicle 1. As a result, the steering wheels of the vehicle 1 are driven according to the target torque, and the behavior of the vehicle 1 fluctuates according to the target torque.

[0030] Figure 4(A) shows an example of the waveform of the required torque. Figure 4(B) shows an example of the waveform of the fluctuating torque. Figure 4(C) shows an example of the waveform of the target torque. When the required torque ta becomes A (a constant value) at a certain timing, a rectangular wave is generated as a fluctuating torque tb corresponding to the vehicle speed v, and a target torque tc is generated with a waveform in which the fluctuating torque tb is added to the required torque ta. The driving control unit 21 outputs the target torque tc with a waveform as shown in Figure 4(C) to the motor 30. As a result, the motor 30 drives the steering wheels of the vehicle 1 according to the target torque tc input from the driving control unit 21. As a result, the behavior of the vehicle 1 fluctuates according to the target torque tc, so the driver can feel the fluctuating behavior of the vehicle 1.

[0031] Here, the addition of fluctuating torque (i.e., a change in the behavior of vehicle 1) is performed when the likelihood of vehicle 1 slipping increases. This allows the driver to sense the change in the behavior of vehicle 1, thereby making the driver aware of the possibility of vehicle 1 slipping.

[0032] Figure 5(A) shows an example of the waveform of the required torque. Figure 5(B) shows an example of the waveform of the fluctuating torque. Figure 5(C) shows an example of the waveform of the target torque. Figure 5(B) illustrates the fluctuating torque tb generated when the vehicle speed v is higher than that in Figure 4(B). The peak value of the fluctuating torque tb shown in Figure 5(B) is larger than the peak value of the fluctuating torque tb shown in Figure 4(B). As a result, the change in the behavior of vehicle 1 that occurs based on the target torque tc shown in Figure 5(C) is larger than the change in the behavior of vehicle 1 that occurs based on the target torque tc shown in Figure 4(C). Consequently, when vehicle 1 is moving at high speed and the possibility of vehicle 1 slipping increases, the driver can easily perceive the fluctuating behavior of vehicle 1.

[0033] In this embodiment, the fluctuation range, period, and waveform of the fluctuating torque remain constant regardless of the magnitude of the required torque. This allows the driver to be aware of the possibility of vehicle 1 slipping even when the required torque is small, such as on road surfaces where the possibility of vehicle 1 slipping is high (for example, on snow or ice).

[0034] <2. Variant> Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to these embodiments, and various modifications are possible.

[0035] [Differentiation A] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the variable torque based on longitudinal acceleration instead of vehicle speed. Longitudinal acceleration is the acceleration acting on the vehicle 1 in the longitudinal direction. The driving control unit 21 (variable torque derivation unit 23) derives longitudinal acceleration based on acceleration data obtained from the acceleration sensor 13.

[0036] Figure 6 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 derives the longitudinal acceleration a based on the acceleration data obtained from the acceleration sensor 13 (step S301). Next, the driving control unit 21 calculates that the longitudinal acceleration a is 1 m / s². 2 In this case (step S302; Y), longitudinal acceleration a = 1 m / s² 2 The fluctuating torque corresponding to this is derived (step S303). The driving control unit 21 determines that the longitudinal acceleration a is 5 m / s 2 If this is the case (step S302; N, step S304; Y), then longitudinal acceleration a = 5 m / s² 2 The corresponding variable torque is derived (step S305).

[0037] For deriving the fluctuating torque, for example, a function with longitudinal acceleration a as a variable can be used, or table data in which the fluctuating torque is associated with each longitudinal acceleration a can be used. The method for deriving the fluctuating torque is not limited to the method shown in Figure 6.

[0038] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the acceleration obtained from the acceleration sensor 13 installed in the vehicle 1. As a result, the steering wheels of the vehicle 1 are driven according to the target torque, and the behavior of the vehicle 1 fluctuates according to the target torque. Consequently, the driver can feel the fluctuating behavior of the vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of the vehicle 1) is performed when the possibility of the vehicle 1 slipping increases. By making the driver feel the change in the behavior of the vehicle 1, the possibility of the vehicle 1 slipping can be made to the driver.

[0039] [Variation B] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be able to change at least one of the fluctuation range, period, and waveform of the variable torque based on the vehicle body slip angular velocity instead of the vehicle speed. The vehicle body slip angular velocity can be derived, for example, using the following formula. The driving control unit 21 (variable torque derivation unit 23) derives the vehicle body slip angular velocity based, for example, the angular velocity data obtained from the angular velocity sensor 14, the acceleration data obtained from the acceleration sensor 13, and the speed data obtained from the vehicle speed sensor 12.

[0040] b = γ - Ay / v b: Vehicle slip angular velocity Ay: Lateral acceleration γ: Yaw angular velocity v: Vehicle 1's speed

[0041] Figure 7 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 derives the vehicle body slip angular velocity b based on the angular velocity data obtained from the angular velocity sensor 14, the acceleration data obtained from the acceleration sensor 13, and the speed data obtained from the vehicle speed sensor 12 (step S401). Next, if the vehicle body slip angular velocity b is 0.1 rad / s (step S402; Y), the driving control unit 21 derives the fluctuating torque corresponding to the vehicle body slip angular velocity b = 0.1 rad / s (step S403). If the vehicle body slip angular velocity b is 0.5 rad / s (step S402; N, step S404; Y), the driving control unit 21 derives the fluctuating torque corresponding to the vehicle body slip angular velocity b = 0.5 rad / s (step S405).

[0042] For deriving the fluctuating torque, for example, a function with vehicle body slip angular velocity b as a variable can be used, or table data in which the fluctuating torque is associated with each vehicle body slip angular velocity b can be used. The method for deriving the fluctuating torque is not limited to the method shown in Figure 7.

[0043] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the angular velocity, acceleration, and speed obtained from the angular velocity sensor 14, acceleration sensor 13, and vehicle speed sensor 12 installed on the vehicle 1. As a result, the steering wheels of the vehicle 1 are driven according to the target torque, and the behavior of the vehicle 1 fluctuates according to the target torque. Consequently, the driver can perceive the fluctuating behavior of the vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of the vehicle 1) is performed when the possibility of the vehicle 1 slipping increases. By making the driver perceive the change in the behavior of the vehicle 1, the possibility of the vehicle 1 slipping can be made known to the driver.

[0044] [Differentiation C] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the variable torque based on the self-aligning torque instead of the vehicle speed. The driving control unit 21 (variable torque derivation unit 23) is capable of deriving the self-aligning torque based on any of the steering angle, steering torque, and steering assist torque. Self-aligning torque refers to the restoring force generated in the steering mechanism when the tires rotate. For example, the driving control unit 21 (variable torque derivation unit 23) derives the self-aligning torque based on any one of the steering angle data obtained from the steering angle sensor 15, the steering torque data obtained from the steering torque sensor 16, and the steering assist torque derived by the EPS control unit.

[0045] Figure 8 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 derives the self-aligning torque c based on one of the steering angle data obtained from the steering angle sensor 15, the steering torque data obtained from the steering torque sensor 16, and the steering assist torque derived by the EPS control unit (step S501). Next, if the self-aligning torque c is 1 Nm (step S502; Y), the driving control unit 21 derives the fluctuating torque corresponding to the self-aligning torque c = 1 Nm (step S503). If the self-aligning torque c is 2 Nm (step S502; N, step S504; Y), the driving control unit 21 derives the fluctuating torque corresponding to the self-aligning torque c = 2 Nm (step S505).

[0046] For deriving the fluctuating torque, for example, a function with self-aligning torque c as a variable can be used, or table data in which the fluctuating torque is associated with each self-aligning torque c can be used. The method for deriving the fluctuating torque is not limited to the method shown in Figure 8.

[0047] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the self-aligning torque. As a result, the steering wheels of vehicle 1 are driven according to the target torque, and the behavior of vehicle 1 fluctuates according to the target torque. Consequently, the driver can perceive the fluctuating behavior of vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of vehicle 1) is performed when the likelihood of vehicle 1 slipping increases. By making the driver perceive the change in the behavior of vehicle 1, the possibility of vehicle 1 slipping can be made known to the driver.

[0048] [Differentiation D] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the variable torque based on the road surface friction coefficient instead of the vehicle speed. The driving control unit 21 (variable torque derivation unit 23) derives the road surface friction coefficient based on the detection result of the road surface friction coefficient sensor 17, for example.

[0049] Figure 9 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 derives the road surface friction coefficient μ based on the detection result of the road surface friction coefficient sensor 17 (step S601). Next, if the road surface friction coefficient μ is 0.9 (step S602; Y), the driving control unit 21 derives the fluctuating torque corresponding to the road surface friction coefficient μ = 0.9 (step S603). If the road surface friction coefficient μ is 0.2 (step S602; N, step S604; Y), the driving control unit 21 derives the fluctuating torque corresponding to the road surface friction coefficient μ = 0.2 (step S605).

[0050] For deriving the fluctuating torque, for example, a function with the road surface friction coefficient μ as a variable can be used, or table data in which the fluctuating torque is associated with each road surface friction coefficient μ can be used. The method for deriving the fluctuating torque is not limited to the method shown in Figure 9.

[0051] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the road friction coefficient obtained from the road friction coefficient sensor 17 installed on the vehicle 1. As a result, the steering wheels of the vehicle 1 are driven according to the target torque, and the behavior of the vehicle 1 fluctuates according to the target torque. Consequently, the driver can feel the fluctuating behavior of the vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of the vehicle 1) is performed when the possibility of the vehicle 1 slipping increases. By making the driver feel the change in the behavior of the vehicle 1, the possibility of the vehicle 1 slipping can be made to the driver.

[0052] [Differentiation Example E] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be able to change at least one of the fluctuation range, period, and waveform of the variable torque based on the turning state of the vehicle 1, instead of the vehicle speed. The driving control unit 21 (variable torque derivation unit 23) may be able to change at least one of the fluctuation range, period, and waveform of the variable torque based on, for example, the lateral acceleration, which is one of the indicators of the turning state of the vehicle 1. The driving control unit 21 (variable torque derivation unit 23) derives the lateral acceleration based on, for example, the detection result of the acceleration sensor 13.

[0053] Figure 10 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 derives the lateral acceleration d based on the detection result of the acceleration sensor 13 (step S701). Next, the driving control unit 21 calculates that the lateral acceleration d is 1 m / s². 2 In this case (step S702; Y), the lateral acceleration d = 1 m / s² 2 The fluctuating torque corresponding to the lateral acceleration d is derived (step S703). The driving control unit 21 determines that the lateral acceleration d is 5 m / s 2 In this case (step S702; N, step S704; Y), the lateral acceleration d = 5 m / s² 2 The corresponding variable torque is derived (step S705).

[0054] For example, the fluctuating torque can be derived using a function with lateral acceleration d as a variable, or using table data where the fluctuating torque is associated with each lateral acceleration d. The method for deriving the fluctuating torque is not limited to the method shown in Figure 10.

[0055] In this modified example, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the variable torque based on, for example, the steering angle, which is one of the indicators of the turning state of the vehicle 1.

[0056] In this modified example, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the variable torque based on, for example, the yaw angular velocity, which is one of the indicators of the turning state of the vehicle 1.

[0057] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the turning state of vehicle 1. As a result, the steering wheels of vehicle 1 are driven according to the target torque, and the behavior of vehicle 1 fluctuates according to the target torque. Consequently, the driver can perceive the fluctuating behavior of vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of vehicle 1) is performed when the likelihood of vehicle 1 slipping increases. By making the driver perceive the change in the behavior of vehicle 1, the possibility of vehicle 1 slipping can be made known to the driver.

[0058] [Modification F] In the above embodiment, the driving control unit 21 (variable torque derivation unit 23) may be capable of changing at least one of the fluctuation range, period, and waveform of the fluctuating torque based on the torsional resonance frequency of the vehicle 1's tires, instead of the vehicle speed. The driving control unit 21 (variable torque derivation unit 23) obtains the torsional resonance frequency by, for example, reading the torsional resonance frequency of the vehicle 1's tires from the memory in the control unit 20.

[0059] Figure 11 shows an example of the procedure for deriving the fluctuating torque in step S104. First, the driving control unit 21 obtains the torsional resonance frequency f of the vehicle 1's tires from, for example, the memory in the control unit 20 (step S801). Next, if the driving control unit 21 is set to add a fluctuating torque to the requested torque (step S802; Y), it derives a fluctuating torque corresponding to the torsional resonance frequency f (step S803). The driving control unit 21 sets the period of the fluctuating torque to, for example, the reciprocal of the torsional resonance frequency f. When the period of the fluctuating torque is equal to the reciprocal of the torsional resonance frequency f, the behavior (fluctuation) of the vehicle 1 becomes more violent compared to when the period of the fluctuating torque is not equal to the reciprocal of the torsional resonance frequency f.

[0060] In this modified example, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the torsional resonance frequency f set in the driving control unit 21. As a result, the steering wheels of vehicle 1 are driven according to the target torque, and the behavior of vehicle 1 fluctuates according to the target torque. Consequently, the driver can feel the fluctuating behavior of vehicle 1. Here, the addition of the fluctuating torque (i.e., the change in the behavior of vehicle 1) is performed when the possibility of vehicle 1 slipping increases. By making the driver feel the change in the behavior of vehicle 1, the possibility of vehicle 1 slipping can be made to the driver.

[0061] In this modified example, the driving control unit 21 (variable torque derivation unit 23) may, for example, set the period of the variable torque to a value that is deviated from the reciprocal of the torsional resonance frequency f, as shown in Figure 12 (Figure 12, step S903). The driving control unit 21 (variable torque derivation unit 23) may, for example, move the period of the variable torque closer to or further away from the reciprocal of the torsional resonance frequency f. Even in this case, the driver can be made aware of the possibility of the vehicle 1 slipping by making the driver feel the change in the behavior of the vehicle 1.

[0062] [Differentiation G] In the above embodiment and its modified form, the driving control unit 21 (variable torque derivation unit 23) may further correct the variable torque according to the magnitude of the required torque.

[0063] Figure 13 shows an example of the procedure for deriving the fluctuating torque in step S104. The driving control unit 21 derives the fluctuating torque using the method shown in the above embodiment and its modified examples. Furthermore, when the required torque becomes A (a constant value) (step S1001; Y), the driving control unit 21 performs a correction on the derived fluctuating torque according to the required torque A (step S1002). Furthermore, when the required torque becomes B (a constant value) (step S1003; Y), the driving control unit 21 performs a correction on the derived fluctuating torque according to the required torque B (step S1004).

[0064] For correcting fluctuating torque, it is possible to use, for example, a function with the required torque as a variable, or table data in which correction coefficients are associated with each required torque. The method for correcting fluctuating torque is not limited to the method shown in Figure 13.

[0065] In this modified version, the fluctuating torque is corrected according to the magnitude of the required torque. In this case, for example, when the road surface conditions increase the likelihood of vehicle 1 slipping even with a small required torque (e.g., snow or ice), increasing the fluctuating torque can alert the driver to the possibility of vehicle 1 slipping.

[0066] [Modification H] In the above embodiment and its modified form, the waveform of the fluctuating torque tb may be a sine wave, for example, as shown in Figure 14(B). In this case, the waveform of the target torque tc will be a sine wave, for example, as shown in Figure 14(C). Even in this case, the driver can be alerted to the possibility of vehicle 1 slipping.

[0067] [Modification I] In the above embodiment and its modifications, the vehicle 1 may further include a mode setting unit 40, as shown in Figure 15, for example. The mode setting unit 40 is a user interface that accepts the setting of a driving mode according to the input from the driver. The mode setting unit 40 is configured, for example, by a touch panel. The mode setting unit 40 is capable of outputting data about the accepted driving mode to the driving control unit 21. The driving control unit 21 is capable of setting a variable torque based on the driving mode input from the mode setting unit 40. The driving control unit 21 may be capable of determining whether or not to add a variable torque to the requested torque according to the driving mode.

[0068] Figure 16 shows an example of the procedure for deriving the variable torque in step S104. First, the driving control unit 21 obtains the driving mode e from the mode setting unit 40 (step S1101). Next, the driving control unit 21 determines whether the obtained driving mode e is a mode that adds a variable torque to the requested torque (step S1102). If the obtained driving mode e is a mode that adds a variable torque to the requested torque (step S1102; Y), the driving control unit 21 sets the variable torque according to the driving mode e (step S1103). If the obtained driving mode e is not a mode that adds a variable torque to the requested torque (step S1102; N), the driving control unit 21 sets the requested torque as the target torque.

[0069] Figure 17 shows an example of the procedure for deriving the variable torque in step S104. First, the driving control unit 21 obtains the driving mode e from the mode setting unit 40 (step S1201). Next, if the obtained driving mode e is the normal mode (step S1202; Y), the driving control unit 21 sets the variable torque according to the normal mode (step S1203). At this time, the driving control unit 21 may, for example, use the requested torque as the target torque. If the obtained driving mode e is the sport mode (step S1202; N, step S1204; Y), the driving control unit 21 sets the variable torque according to the sport mode (step S1205). At this time, the driving control unit 21 may, for example, derive the target torque by adding the variable torque to the requested torque.

[0070] In this modified version, a variable torque is set according to the driving mode. Specifically, it is determined whether or not to add a variable torque to the required torque depending on the driving mode. In this case, for example, in a sport mode where high-speed driving is expected, adding a variable torque to the required torque can alert the driver to the possibility of vehicle 1 slipping.

[0071] <3. Application Examples> Next, an example of the application of the control unit 20 according to the above embodiment and its modified form will be described. Figure 18 shows a schematic configuration example of a vehicle control system 100 according to one application example of the present disclosure. The vehicle control system 100 comprises a plurality of vehicles 1 and a server device 2. The plurality of vehicles 1 and the server device 2 are connected to a network NW.

[0072] A network (NW) is a communication network that uses a standard communication protocol (TCP / IP) commonly used on the internet. A network (NW) may also be a secure network that uses its own proprietary communication protocol.

[0073] Each vehicle 1 is configured to communicate with a server device 2 via a network NW. Each vehicle 1 includes, for example, a sensor unit 10, a control unit 20, a motor 30, and a communication unit 50, as shown in Figure 19. The communication unit 50 is a communication interface for communicating with the server device 2 via the network NW. The communication unit 50 exchanges data with the server device 2 via the network NW, for example. The communication unit 50 transmits various sensor data obtained by the sensor unit 10 to the server device 2 via the network NW. The communication unit 50 receives, for example, fluctuating torque data obtained by the server device 2 from the server device 2 via the network NW. The communication unit 50 outputs the received fluctuating torque data to the control unit 20, for example.

[0074] The server device 2 includes, for example, a communication unit 210, a control unit 220, and a storage unit 230, as shown in Figure 20. The communication unit 210 is a communication interface for communicating with each vehicle 1 via a network NW. The communication unit 210 exchanges data with each vehicle 1 via the network NW, for example. The communication unit 210 receives various sensor data obtained by the vehicle 1 from the vehicle 1 via the network NW. The communication unit 210 outputs the received sensor data to the control unit 220, for example.

[0075] The memory unit 230 stores the program 231 that is executed by the control unit 220. The memory unit 230 is composed of, for example, RAM (Random Access Memory), ROM (Read Only Memory), auxiliary storage device (hard disk, etc.). The program 231 causes the control unit 220 to execute a series of procedures in the requested torque derivation unit 22 and the fluctuating torque derivation unit 23.

[0076] The control unit 220 is configured to include, for example, a CPU (Central Processing Unit), and executes, for example, a program 231 stored in the storage unit 230. The control unit 220 has, for example, a requested torque derivation unit 22 and a fluctuating torque derivation unit 23, as shown in Figure 20. The control unit 220 executes a series of procedures in the requested torque derivation unit 22 and the fluctuating torque derivation unit 23. The control unit 220 outputs the derived fluctuating torque data to the vehicle 1 via the communication unit 210.

[0077] In this application example, the target torque is derived by adding the fluctuating torque derived by the server device 2 to the requested torque corresponding to the acceleration request, and the torque of the motor 30 is controlled based on the derived target torque. As a result, the steering wheels of the vehicle 1 are driven according to the target torque, and the behavior of the vehicle 1 fluctuates according to the target torque. Consequently, since the behavior of the vehicle 1 fluctuates according to the target torque tc, the driver can feel the fluctuating behavior of the vehicle 1. Therefore, the driver can be made aware of the possibility of the vehicle 1 slipping.

[0078] The effects described herein are illustrative only, and the effects of this disclosure are not limited to those described herein. Therefore, other effects may be obtained with respect to this disclosure.

[0079] Furthermore, this disclosure may take the following forms: (1) A vehicle control device for controlling a vehicle that is driven by a motor, The system includes a control unit capable of deriving a target torque by adding a periodically fluctuating torque to a requested torque corresponding to the driver's acceleration request, and controlling the motor torque based on the derived target torque. The control unit is capable of changing at least one of the fluctuation range, period, and waveform of the fluctuating torque based on any of the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, turning state, and the torsional resonance frequency of the vehicle's tires. Vehicle control system. (2) The control unit is capable of keeping the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque. (1) The vehicle control device described above. (3) The control unit is capable of correcting the fluctuation range, period, and waveform of the fluctuating torque in accordance with the magnitude of the required torque. (1) The vehicle control device described above. (4) The control unit is capable of determining whether or not to add the variable torque to the requested torque depending on the driving mode. A vehicle control device as described in any one of (1) to (3). (5) The control unit is capable of deriving the self-aligning torque based on any of the steering angle, steering torque, or steering assist torque. A vehicle control device as described in any one of (1) to (4). (6) The aforementioned turning state is determined by the steering angle, lateral acceleration and Yaw angular velocity It is one of the following A vehicle control device as described in any one of (1) to (4). (7) A vehicle control method for controlling a vehicle that is driven by a motor, The system derives a target torque by adding a periodically fluctuating torque to the requested torque corresponding to the driver's acceleration request, and controls the motor torque based on the derived target torque. Based on the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, and turning condition, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed. including Vehicle control method. (8) This includes making the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque. (7) The vehicle control method described above. (9) This includes correcting the fluctuation range, period, and waveform of the fluctuating torque in accordance with the magnitude of the required torque. (7) The vehicle control method described above. (10) This includes determining whether or not to add the variable torque to the requested torque depending on the driving mode. A vehicle control method as described in any one of (7) to (9). (11) Based on the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, and turning state, the period of the fluctuating torque is brought closer to or further away from the reciprocal of the torsional resonance frequency of the tires provided on the vehicle. A vehicle control method described in any one of (7) to (10).

[0080] The control unit 20 shown in Figures 1 and 15 can be implemented by a circuit including at least one semiconductor integrated circuit, such as at least one processor (e.g., a central processing unit (CPU)), at least one application-specific integrated circuit (ASIC) and / or at least one field-programmable gate array (FPGA). At least one processor can be configured to perform all or some of the functions of the control unit 20 shown in Figures 1 and 15 by reading instructions from at least one non-temporary, tangible computer-readable medium. Such a medium can take various forms, including, but is not limited to, various magnetic media such as hard disks, various optical media such as CDs or DVDs, and various semiconductor memories (i.e., semiconductor circuits) such as volatile memory or non-volatile memory. Volatile memory may include DRAM and SRAM. Non-volatile memory may include ROM and NVRAM. The ASIC is an integrated circuit (IC) specialized to perform all or some of the functions of the control unit 20 shown in Figures 1 and 15. An FPGA is an integrated circuit designed to be configurable after manufacturing to perform all or some of the various functions of the control unit 20 shown in Figures 1 and 15.

Claims

1. A vehicle control device for controlling a vehicle that is driven by a motor, The system includes a control unit capable of deriving a target torque by adding a periodically fluctuating torque to a required torque corresponding to an acceleration request, and controlling the motor torque based on the derived target torque. The control unit is capable of changing at least one of the fluctuation range, period, and waveform of the fluctuating torque based on any of the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, turning state, and the torsional resonance frequency of the vehicle's tires, in order to alert the driver to the possibility of the vehicle slipping. The control unit is capable of adjusting the period of the fluctuating torque to be closer to or further away from the reciprocal of the torsional resonance frequency of the tires provided on the vehicle, based on any of the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, and turning state. Vehicle control system.

2. The control unit is capable of keeping the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque. The vehicle control device according to claim 1.

3. The control unit is capable of correcting the fluctuation range, period, and waveform of the fluctuating torque according to the magnitude of the required torque. The vehicle control device according to claim 1.

4. The control unit is capable of determining whether or not to add the variable torque to the requested torque depending on the driving mode. The vehicle control device according to claim 1.

5. The control unit is capable of deriving the self-aligning torque based on any of the steering angle, steering torque, or steering assist torque. The vehicle control device according to claim 1.

6. The aforementioned turning state is one of the steering angle, lateral acceleration, or yaw rate. The vehicle control device according to claim 1.

7. A vehicle control method for controlling a vehicle that is driven by a motor, The system derives a target torque by adding a periodically fluctuating torque to the required torque corresponding to the acceleration requirement, and controls the motor torque based on the derived target torque. In order to alert the driver to the possibility of the vehicle slipping, at least one of the fluctuation range, period, and waveform of the fluctuating torque is changed based on the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, turning condition, and the torsional resonance frequency of the vehicle's tires. Based on the vehicle's speed, longitudinal acceleration, vehicle body slip angular velocity, self-aligning torque, road surface friction coefficient, and turning state, the period of the fluctuating torque is brought closer to or further away from the reciprocal of the torsional resonance frequency of the tires provided on the vehicle. including Vehicle control method.

8. This includes making the fluctuation range, period, and waveform of the fluctuating torque constant regardless of the magnitude of the required torque. The vehicle control method according to claim 7.

9. This includes correcting the fluctuation range, period, and waveform of the fluctuating torque in accordance with the magnitude of the required torque. The vehicle control method according to claim 7.

10. This includes determining whether or not to add the variable torque to the requested torque depending on the driving mode. The vehicle control method according to claim 7.

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