Vehicle control device and vehicle control method

Abstract

A vehicle control device according to an embodiment of the present disclosure is a device capable of controlling a vehicle that travels under motor driving. The vehicle control device comprises a control unit capable of deriving a target torque by adding a periodically varying variable torque to a required torque according to an acceleration demand, and controlling the torque of a motor on the basis of the derived target torque. The control unit is capable of varying the gain of the variable torque in accordance with the gear stage when the vehicle is in a transient state different from a steady state in which the acceleration and angular velocity of the vehicle are at or below predetermined values.

Description

Vehicle control device and vehicle control method

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

[0002] 2. Description of the Related Art Various techniques have been proposed for operating a vehicle more safely (see, for example, Patent Documents 1 and 2).

[0003] JP 2017-055618 A JP 2011-205799 A

[0004] A vehicle control device according to an embodiment of the present disclosure is a device capable of controlling a vehicle driven by a motor. The vehicle control device includes a control unit capable of deriving a target torque by adding a periodically fluctuating torque to a required torque according to an acceleration request, and controlling the torque of the motor based on the derived target torque. The control unit is capable of changing a gain of the fluctuating torque depending on a gear position when the vehicle is in a transient state different from a steady state in which the acceleration and angular velocity of the vehicle are equal to or less than a predetermined value.

[0005] A vehicle control method according to an embodiment of the present disclosure is a method capable of controlling a vehicle that runs by being driven by a motor. This vehicle control method includes the following two steps: (A) deriving a target torque by adding a periodically fluctuating torque to a required torque according to an acceleration request, and performing torque control of the motor based on the derived target torque; and (B) changing the gain of the fluctuating torque according to the gear position when the vehicle is in a transient state different from a steady state in which the acceleration and angular velocity are equal to or less than a predetermined value.

[0006] The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate one embodiment and, together with the description, serve to explain the principles of the disclosure.

[0007] FIG. 1 is a diagram illustrating an example of a functional block of a vehicle equipped with a vehicle control device according to an embodiment of the present disclosure. FIG. 2(A) is a diagram illustrating an example of a waveform of a required torque (regenerative torque). FIG. 2(B) is a diagram illustrating an example of a waveform of a fluctuating torque. FIG. 2(C) is a diagram illustrating an example of a waveform of a target torque. FIG. 3(A) is a diagram illustrating an example of a waveform of a required torque (powering torque). FIG. 3(B) is a diagram illustrating an example of a waveform of a fluctuating torque. FIG. 3(C) is a diagram illustrating an example of a waveform of a target torque. FIG. 4 is a diagram illustrating an example of a procedure for deriving fluctuating torque in the traveling control unit of FIG. 1. FIG. 5 is a diagram illustrating an example of a procedure for setting a gain of the fluctuating torque derived by the procedure of FIG. 4, and an example of a procedure for deriving a target torque. FIG. 6 is a diagram illustrating an example of a state in which a vehicle passes through a corner. FIG. 7 is a diagram illustrating an example of a target torque waveform when the vehicle passes through the corner of FIG. 6.

[0008] In a vehicle driven by a motor, motor output is smoother than engine output. Therefore, a smooth steering feel can be obtained in all driving conditions, such as straight driving, lane changes, and curve driving. However, while such a steering feel can be obtained, it is difficult for the driver to grasp the grip state between the tires and the road surface when turning (for example, when cornering, turning right or left at an intersection, or changing lanes), making it difficult to feel a sense of security or a sense of control when steering. It is desirable to provide a vehicle control device and a vehicle control method that can give the driver a sense of security and a sense of control when steering when turning.

[0009] Some exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the following description illustrates one 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 position of each part, and the connection method of each part, is merely an example and should not be construed as limiting the present disclosure. Furthermore, in the following exemplary embodiments, components not described in independent claims based on the highest concept of the present disclosure are optional and may be provided as needed. The drawings are schematic and are not intended to be drawn to scale. Throughout this specification and the drawings, components having substantially the same function and configuration are designated by the same reference numerals, and redundant description will be omitted. Furthermore, components not directly related to one embodiment of the present disclosure are not shown in the drawings.

[0010] 1. Embodiment [Configuration Example] Fig. 1 illustrates a schematic configuration example of a vehicle 1 equipped with a control unit 20 according to an embodiment of the present disclosure. The control unit 20 corresponds to a specific example of a "control unit" in the present disclosure. The vehicle 1 is capable of traveling by motor drive. As shown in Fig. 1, the vehicle 1 includes, for example, a sensor unit 10, a control unit 20, a storage unit 30, a control flag input unit 40, and a motor 50.

[0011] The sensor unit 10 is configured to include various sensors mounted on the vehicle 1. For example, as shown in Fig. 1, the sensor unit 10 includes an accelerator operation amount sensor 11, a gear position sensor 12, and a vehicle state amount sensor 13. The sensor unit 10 may include sensors other than those described above.

[0012] The accelerator operation amount sensor 11 is capable of detecting the accelerator operation amount from the depression amount of the accelerator pedal. The accelerator operation amount sensor 11 is capable of outputting data on the detected accelerator operation amount (accelerator operation amount data Da) to the control unit 20. When the accelerator operation amount data Da is zero, the control unit 20 is capable of regarding the acceleration request from the driver as a deceleration request. When the accelerator operation amount data Da is greater than zero, the control unit 20 is capable of regarding the acceleration request from the driver as an acceleration request.

[0013] The gear stage sensor 12 is a sensor capable of detecting the current gear stage. The gear stage sensor 12 may be, for example, an input position detection sensor capable of detecting the current gear stage by detecting the input position of a shift lever. The gear stage sensor 12 may be, for example, a signal detection sensor capable of detecting the current gear stage by detecting a signal output by operating a paddle shift. The gear stage sensor 12 is capable of outputting data on the detected gear stage (gear stage data Dg) to the control unit 20.

[0014] For example, when the gear is in first gear, the gear speed sensor 12 outputs D1 as the gear speed data Dg. For example, when the gear is in second gear, the gear speed sensor 12 outputs D2 as the gear speed data Dg. For example, when the gear is in third gear, the gear speed sensor 12 outputs D3 as the gear speed data Dg. For example, when the gear is in fourth gear, the gear speed sensor 12 outputs D4 as the gear speed data Dg.

[0015] The vehicle state quantity sensor 13 is capable of detecting vehicle state quantities, which are information indicating the state of the vehicle 1. The vehicle state quantity sensor 13 is capable of outputting time-series data (vehicle state quantity data) on the detected vehicle state quantities to the control unit 20. The vehicle state quantity sensor 13 is configured to include, as sensors capable of detecting the vehicle state quantities, for example, a vehicle speed sensor, an acceleration sensor, an angular velocity sensor, a steering angle sensor, and a steering torque sensor.

[0016] The vehicle speed sensor is capable of detecting the speed (vehicle speed) of the vehicle 1. The vehicle speed sensor is capable of outputting time series data (vehicle speed data) about the detected vehicle speed to the control unit 20. The acceleration sensor is capable of detecting acceleration applied to the vehicle 1. The acceleration sensor is capable of outputting time series data (acceleration data) about the detected acceleration in three directions (longitudinal acceleration, lateral acceleration, and vertical acceleration) to the control unit 20. The angular velocity sensor is capable of detecting the angular velocity of the vehicle 1. The angular velocity sensor is capable of outputting time series data (angular velocity data) about the detected three angular velocities (yaw angular velocity, roll angular velocity, and pitch angular velocity) to the control unit 20.

[0017] The steering angle sensor is capable of detecting the steering angle (steering angle) of the steering wheel of the vehicle 1. The steering angle sensor is capable of outputting time-series data (steering angle data) about the detected steering angle to the control unit 20. The steering torque sensor is capable of detecting the steering torque generated by the driver's steering wheel operation. The steering torque sensor is capable of outputting time-series data (steering torque data) about the detected steering torque to the control unit 20.

[0018] 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 configured to include, for example, one or more processors and one or more memories. The control unit 20 may be configured to include, for example, a CPU (Central Processing Unit). In this case, the control unit 20 may be capable of controlling the entire vehicle 1 by, for example, executing a program stored in the storage unit 30.

[0019] The control unit 20 is capable of controlling the vehicle 1 that runs by being driven by a motor. The control unit 20 has, for example, a driving control unit 21 as shown in FIG. 1 . The driving control unit 21 is capable of controlling the running of the vehicle 1 (for example, the torque of the motor 50). The driving control unit 21 has, for example, a required torque derivation unit 22, a fluctuation torque derivation unit 23, and a motor torque control unit 24 as shown in FIG. 1 .

[0020] The required torque derivation unit 22 is capable of deriving a required torque Tr according to an acceleration request. The acceleration request includes the depression of the accelerator pedal or a change in the depression amount of the accelerator pedal, and the number of gears or a change in the gears. The acceleration request includes, for example, accelerator operation amount data Da and gear step data Dg. The required torque derivation unit 22 is capable of deriving the amount of torque (required torque Tr) that should be generated by the motor 50, for example, based on the accelerator operation amount data Da and the gear step data Dg. The acceleration request may be made by the driver during manual driving, or by the cruise control unit 21 during autonomous driving.

[0021] 2A shows an example of the change over time in the required torque Tr (regenerative torque) obtained when the driver releases his / her foot from the accelerator pedal while the vehicle 1 is traveling. Fig. 2A illustrates an example of the manner in which the vehicle 1 decelerates over time, resulting in a decrease in the required torque Tr (regenerative torque) over time. For example, when the accelerator operation amount data Da is zero, the required torque derivation unit 22 is capable of deriving the required torque Tr (regenerative torque) that the motor 50 should generate based on the gear position data Dg.

[0022] 3A shows an example of the change over time in the required torque Tr (powering torque) obtained when the driver depresses the accelerator pedal over time. FIG. 3A illustrates an example of the manner in which the vehicle 1 accelerates over time, and as a result, the required torque Tr (powering torque) also increases over time. The required torque derivation unit 22 is capable of deriving the required torque Tr (powering torque) to be generated by the motor 50 based on, for example, the accelerator operation amount data Da and the gear position data Dg.

[0023] The fluctuating torque derivation unit 23 is capable of deriving the fluctuating torque Tf (FIGS. 2(B) and 3(B)), which fluctuates periodically. FIGS. 2(B) and 3(B) show examples of the time change of the fluctuating torque Tf. The fluctuating torque Tf is intended to intentionally change the behavior of the vehicle 1, thereby giving the driver a sense of security and a good sense of response when steering when turning (for example, when cornering, turning right or left at an intersection, or changing lanes).

[0024] The fluctuation range of the fluctuation torque Tf is, for example, approximately 10% of the magnitude of the required torque Tr. The frequency of the fluctuation torque Tf is, for example, 17 Hz, 20 Hz, or 24 Hz. The waveform of the fluctuation torque Tf is, for example, a rectangular or sinusoidal waveform. The fluctuation range, frequency, and waveform of the fluctuation torque Tf are not limited to those described above. For example, the fluctuation torque derivation unit 23 may be capable of changing at least one of the fluctuation range, frequency, and waveform of the fluctuation torque Tf depending on the magnitude of the required torque Tr. For example, the fluctuation torque derivation unit 23 may be capable of keeping at least one of the fluctuation range, frequency, and waveform of the fluctuation torque Tf constant regardless of the magnitude of the required torque Tr.

[0025] When the gain G of the torque fluctuation Tf is input from the motor torque control unit 24, the torque fluctuation derivation unit 23 can correct the torque fluctuation Tf based on the input gain G. For example, the torque fluctuation derivation unit 23 can multiply the torque fluctuation Tf by the gain G, thereby deriving a new torque fluctuation (Tf×G). The gain G will be described in detail later.

[0026] The motor torque control unit 24 derives the target torque Tg (FIGS. 2(C) and 3(C)) by adding a fluctuating torque (Tf or Tf×G) to the required torque Tr, and is able to control the torque of the motor 50 based on the derived target torque Tg. FIGS. 2(C) and 3(C) show examples of how the target torque Tg changes over time.

[0027] The motor torque control unit 24 is capable of determining whether the vehicle 1 is in a steady state or a transient state based on, for example, vehicle state quantity data (acceleration data and angular velocity data) obtained from the vehicle state quantity sensor 13. The "steady state" refers to a state in which the acceleration data and angular velocity data are equal to or less than a predetermined value (threshold value). The "steady state" includes constant-speed straight-line traveling. The "steady state" also includes a state in which the vehicle travels at a speed within a range recognized as constant-speed straight-line traveling when the steering angle is 0° or a very small angle. The "transient state" refers to a state different from the "steady state." The "transient state" includes turning (e.g., cornering, turning right or left at an intersection, or changing lanes). The "transient state" also includes, for example, steady-state circular turning. When the steering angle is greater than a predetermined value (threshold value), the vehicle 1 is turning and can be said to be in a "transient state."

[0028] The motor torque control unit 24 is capable of, for example, changing the gain G of the fluctuation torque Tf depending on the gear position. For example, when the vehicle 1 is in a transient state, the motor torque control unit 24 is capable of changing the gain G of the fluctuation torque Tf depending on the gear position. For example, the motor torque control unit 24 is capable of setting the gain G of the fluctuation torque Tf based on the gear position data Dg obtained by the gear position sensor 12.

[0029] For example, when the required torque Tr in the transient state is a regenerative torque, the motor torque control unit 24 can set the gain G of the fluctuating torque Tf when the gear is in first gear to G1 (first gain). For example, when the required torque Tr in the transient state is a regenerative torque, the motor torque control unit 24 can set the gain G of the fluctuating torque Tf when the gear is in second gear to G2 (first gain). For example, when the required torque Tr in the transient state is a regenerative torque, the motor torque control unit 24 can set the gain G of the fluctuating torque Tf when the gear is in third gear to G3 (first gain). For example, when the required torque Tr in the transient state is a regenerative torque, the motor torque control unit 24 can set the gain G of the fluctuating torque Tf when the gear is in fourth gear to G4 (first gain). Here, the magnitude of the gain G increases as the gear (gear ratio) decreases. For example, G1 > G2 > G3 > G4 holds true.

[0030] For example, when the required torque Tr in the transient state is a powering torque, the motor torque control unit 24 can set the gain G of the fluctuation torque Tf when the gear is in first gear to G5 (second gain) which is smaller than G1 (first gain). For example, when the required torque Tr in the transient state is a powering torque, the motor torque control unit 24 can set the gain G of the fluctuation torque Tf when the gear is in second gear to G6 (second gain) which is smaller than G2 (first gain). For example, when the required torque Tr in the transient state is a powering torque, the motor torque control unit 24 can set the gain G of the fluctuation torque Tf when the gear is in third gear to G7 (second gain) which is smaller than G3 (first gain). For example, when the required torque Tr in the transient state is a powering torque, the motor torque control unit 24 can set the gain G of the fluctuation torque Tf when the gear is in fourth gear to G8 (second gain) which is smaller than G4 (first gain). Here, the magnitude of the gain G increases as the gear stage (gear ratio) decreases. For example, G5>G6>G7>G8 holds true.

[0031] The motor torque control unit 24 can determine whether or not the fluctuating torque Tf needs to be added to the required torque Tr, for example, based on a control flag 31 described below. For example, when the control flag 31 indicates a torque fluctuation control mode, the motor torque control unit 24 can derive the target torque Tg by adding the fluctuating torque Tf to the required torque Tr. The "torque fluctuation control mode" refers to a mode in which torque control is performed by oscillating the target torque Tg at a low frequency (e.g., 17 Hz, 20 Hz, or 24 Hz). For example, when the control flag 31 indicates a normal mode, the motor torque control unit 24 can set the required torque Tr as the target torque Tg. The "normal mode" refers to a mode in which torque control is performed according to the required torque Tr without oscillating the target torque Tg at a low frequency.

[0032] The storage unit 30 stores, for example, a control flag 31 input from the control flag input unit 40. The storage unit 30 may store, for example, a program executed by the control unit 20. This program is a program for causing the control unit 20 to execute a series of procedures for controlling the entire vehicle 1. The storage unit 30 is configured by, for example, a random access memory (RAM), a read only memory (ROM), an auxiliary storage device (such as a hard disk), etc.

[0033] The control flag input unit 40 is capable of receiving input of a control flag 31 from the driver. The control flag input unit 40 is, for example, a paddle shifter attached to a steering wheel. For example, when the driver simultaneously presses and holds the left and right paddle shifters, the control flag input unit 40 can store "1" as the control flag 31 in the storage unit 30. For example, when the driver simultaneously presses and holds the left and right paddle shifters again after previously storing "1" as the control flag 31 in the storage unit 30, the control flag input unit 40 can store "0" as the control flag 31 in the storage unit 30. For example, when the driver simultaneously presses and holds the left and right paddle shifters again after previously storing "0" as the control flag 31 in the storage unit 30, the control flag input unit 40 can store "1" as the control flag 31 in the storage unit 30.

[0034] When the control flag 31 is "1", it means that the torque fluctuation control mode is selected. When the control flag 31 is "0", it means that the normal mode is selected, in which periodic torque fluctuation control is not performed. Note that the values ​​that the control flag 31 can take are not limited to those described above.

[0035] The motor 50 is configured to drive the steered wheels of the vehicle 1. The motor 50 is capable of driving the steered wheels of the vehicle 1 in accordance with the target torque Tg input from the motor torque control unit 24. In this specification, the steered wheels refer to at least one of the front wheels and the rear wheels. One motor 50 may be provided for the front wheels, and one motor 50 may be provided for the rear wheels. In this case, the cruise control unit 21 may be capable of controlling the motor 50 for the front wheels and the motor 50 for the rear wheels in common. Alternatively, the cruise control unit 21 may be capable of controlling the motor 50 for the front wheels and the motor 50 for the rear wheels independently of each other.

[0036] [Operation] Next, the operation of the driving control unit 21 will be described with reference to Fig. 4. Fig. 4 is a diagram for explaining an example of a procedure for deriving the torque fluctuation Tf. Fig. 5 is a diagram for explaining an example of a procedure for setting the gain G of the torque fluctuation Tf derived by the procedure in Fig. 4, and an example of a procedure for deriving the target torque Tg.

[0037] The traveling control unit 21 acquires an acceleration request from the accelerator operation amount sensor 11 and the gear position sensor 12 (step S101). For example, the traveling control unit 21 acquires accelerator operation amount data Da from the accelerator operation amount sensor 11 and gear position data Dg from the gear position sensor 12. Next, the traveling control unit 21 derives a required torque Tr according to the acquired acceleration request (accelerator operation amount data Da and gear position data Dg) (step S102). For example, when the accelerator operation amount data Da is zero, the traveling control unit 21 derives regenerative torque as the required torque Tr. For example, when the accelerator operation amount data Da is greater than zero, the traveling control unit 21 derives powering torque as the required torque Tr.

[0038] Next, when the control flag 31 input from the control flag input unit 40 indicates the torque fluctuation control mode (step S103; Y), the driving control unit 21 determines whether the vehicle 1 is in a transient state (step S104). As a result, when the vehicle 1 is in a transient state (step S104; Y), the driving control unit 21 derives the periodically fluctuating torque fluctuation Tf (step S105). On the other hand, when the control flag 31 input from the control flag input unit 40 indicates the normal mode (step S103; N), or when the vehicle 1 is not in a transient state, that is, when the vehicle 1 is in a steady state (step S104; N), the driving control unit 21 sets the required torque Tr to the target torque Tg (step S110).

[0039] Next, when the travel control unit 21 derives the fluctuating torque Tf in step S105, it determines whether the required torque Tr in the transient state is regenerative torque (step S106). If the required torque Tr in the transient state is regenerative torque (step S106; Y), the travel control unit 21 sets a gain G (e.g., G1, G2, G3, or G4) corresponding to the gear position (step S107). On the other hand, if the required torque Tr in the transient state is not regenerative torque, that is, if the required torque Tr in the transient state is powering torque (step S106; N), the travel control unit 21 sets a gain G (e.g., G5, G6, G7, or G8) corresponding to the gear position (step S108).

[0040] If the gain G was set in step S107 or step S108, the driving control unit 21 multiplies the torque fluctuation Tf by the gain G to thereby derive a new torque fluctuation (Tf×G) (step S109). Next, the driving control unit 21 derives the target torque Tg by adding the torque fluctuation (Tf×G) to the required torque Tr (step S110). In this manner, the target torque Tg is derived.

[0041] Thereafter, the driving control unit 21 derives the target torque Tg by adding a fluctuating torque (Tf×Ga or Tf×Gb) to the required torque Tr, and controls the torque of the motor 50 based on the derived target torque Tg. In this manner, the torque of the motor 50 is controlled.

[0042] Next, the operation of the driving control unit 21 will be described with reference to FIGS.

[0043] FIG. 6 shows an example of the state of the vehicle 1 passing through a corner. FIG. 7(A) shows an example of the waveform of the target torque Tg when the vehicle 1 passes through a corner. FIG. 7(B) shows an example of the change over time in the accelerator operation amount data Da when the vehicle 1 passes through a corner. FIG. 7(C) shows an example of the change over time in the gear position data Dg when the vehicle 1 passes through a corner. FIG. 7(D) shows an example of the change over time in the on / off state of the torque fluctuation control activation switch when the vehicle 1 passes through a corner. The on / off state of the torque fluctuation control activation switch corresponds to "1" or "0" of the control flag 31 described above. FIG. 7(E) shows an example of the change over time in the state of the vehicle 1 when the vehicle 1 passes through a corner. FIG. 7(E) illustrates an example of the state of the vehicle 1 being in either the steady state described above or the transient state described above.

[0044] First, the vehicle 1 is in fourth gear (D4), the driver is off the accelerator pedal, and the vehicle is in a steady state, with the torque fluctuation control activation switch turned off. At this time, the driver inputs the control flag 31, which indicates the torque fluctuation control mode, via the control flag input unit 40 at time ta. When the vehicle 1 enters a corner at time tb in this state, the cruise control unit 21 detects that the vehicle 1 has entered a transient state. As a result, the cruise control unit 21 multiplies the fluctuation torque Tf by a gain G4 and begins to control the regenerative torque of the motor 50 based on the target torque Tg (= Tr + Tf × G4) whose amplitude fluctuates.

[0045] Thereafter, while the vehicle 1 is turning a corner, the driver operates the shift lever or paddle shifters, or the cruise control unit 21 automatically controls the vehicle to change gears to third gear (D3) at time tc, to second gear (D2) at time td, to third gear (D3) at time tf, and to fourth gear (D4) at time tg. Furthermore, the driver depresses the accelerator pedal at time te when the vehicle 1 enters the second half (starting up) of the corner. When the driver's foot is released from the accelerator pedal, the cruise control unit 21 changes the target torque Tg to regenerative torque (Tr+Tf×G3) at time tc and to regenerative torque (Tr+Tf×G2) at time td. Furthermore, when the driver depresses the accelerator pedal, the cruise control unit 21 changes the target torque Tg to a traction torque (Tr+Tf×G6) at time te, to a traction torque (Tr+Tf×G7) at time tf, and to a traction torque (Tr+Tf×G8) at time tg. As a result, when the vehicle 1 is entering the corner in the first half, the amplitude of the periodic oscillation of the target torque Tg increases as the gear position decreases, as shown in FIG. 7, for example. When the vehicle 1 is exiting the corner in the second half, the amplitude of the periodic oscillation of the target torque Tg decreases as the gear position increases, as shown in FIG. 7, for example.

[0046] [Effects] Next, effects of the control unit 20 according to the embodiment of the present disclosure will be described.

[0047] In this embodiment, in a vehicle 1 driven by a motor, a target torque Tg is derived by adding a periodically fluctuating torque Tf to a required torque Tr corresponding to an acceleration request, and the torque of the motor 50 is controlled based on the derived target torque Tg. When the vehicle 1 is in a transient state, a gain G of the fluctuating torque Tf changes depending on the gear position. This allows the driver to easily grasp the grip state between the tires and the road surface, for example, when turning (e.g., when cornering, turning right or left at an intersection, or changing lanes), and provides a sense of security and a positive response when steering. In this way, the improved driver information in this embodiment provides the driver with a sense of security and a positive response when steering. Furthermore, the appropriate vibration provides the driver with a driving feel similar to that of an internal combustion engine vehicle.

[0048] In this embodiment, it is determined whether the vehicle 1 is in a steady state or a transient state based on the acceleration data and angular velocity data obtained by the vehicle state quantity sensor 13. Furthermore, the gain G of the fluctuation torque Tf is set based on the gear speed data Dg obtained by the gear speed sensor 12. This makes it easier for the driver to grasp the grip state between the tires and the road surface, for example, when turning (for example, when cornering, turning right or left at an intersection, or changing lanes), and allows the driver to feel a sense of security and a good response when steering. In this way, the improved driver information in this embodiment allows the driver to feel a sense of security and a good response when steering. In addition, the appropriate vibration allows the driver to feel a driving sensation similar to that of an internal combustion engine vehicle.

[0049] In this embodiment, the gain G5 of the fluctuating torque Tf when the required torque Tr in the transient state is powering torque and the gear position is first is smaller than the gain G1 of the fluctuating torque Tf when the required torque Tr in the transient state is regenerative torque and the gear position is first. The gain G6 of the fluctuating torque Tf when the required torque Tr in the transient state is powering torque and the gear position is second is smaller than the gain G2 of the fluctuating torque Tf when the required torque Tr in the transient state is regenerative torque and the gear position is second. The gain G7 of the fluctuating torque Tf when the required torque Tr in the transient state is powering torque and the gear position is third is smaller than the gain G3 of the fluctuating torque Tf when the required torque Tr in the transient state is regenerative torque and the gear position is third. The gain G8 of the fluctuating torque Tf when the required torque Tr in the transient state is powering torque and the gear position is fourth is smaller than the gain G4 of the fluctuating torque Tf when the required torque Tr in the transient state is regenerative torque and the gear position is fourth. This makes it possible to achieve smooth acceleration during the latter half (start-up) of a turn (for example, when cornering, turning right or left at an intersection, or changing lanes), while giving the driver a sense of security and a good sense of response when steering.

[0050] In this embodiment, whether or not the fluctuating torque Tf needs to be added to the required torque Tr is determined based on the control flag 31 input via the control flag input unit 40 provided in the vehicle 1, and when the control flag 31 indicates the torque fluctuation control mode, the target torque Tg is derived by adding the fluctuating torque Tf to the required torque Tr. This makes it possible to obtain a driving feeling that meets the driver's needs.

[0051] 2. Modifications The present disclosure has been described above by giving embodiments, but the present disclosure is not limited to these embodiments and various modifications are possible.

[0052] In the above embodiment, one motor 50 may be provided for each front wheel and one for each rear wheel. In this case, the travel control unit 21 may be capable of controlling the motor 50 for the front wheels and the motor 50 for the rear wheels independently of each other. Furthermore, the motor torque control unit 24 may be capable of separately controlling the torque for the front wheels and the torque for the rear wheels.

[0053] In this case, the motor torque control unit 24 can appropriately adjust the driving feel obtained from the front wheels and the driving feel obtained from the rear wheels by changing the gain G of the fluctuating torque Tf separately for the front wheels and the rear wheels, thereby allowing the driver to more accurately feel a sense of security and a good response when steering.

[0054] The effects described in this specification are merely examples, and the effects of the present disclosure are not limited to the effects described in this specification. Therefore, other effects may be obtained with respect to the present disclosure.

[0055] Furthermore, the present disclosure may take the following forms. (1) A vehicle control device capable of controlling a vehicle traveling by motor drive, comprising a control unit capable of deriving a target torque by adding a periodically fluctuating torque to a required torque according to an acceleration request, and performing torque control of the motor based on the derived target torque, wherein the control unit is capable of changing a gain of the fluctuating torque in accordance with a gear stage when the vehicle is in a transient state different from a steady state in which the acceleration and angular velocity of the vehicle are equal to or lower than predetermined values. (2) The vehicle control device described in (1), wherein the control unit is capable of determining whether the vehicle is in the steady state or the transient state based on acceleration data and angular velocity data obtained by a first sensor, and further, is capable of setting a gain of the fluctuating torque based on gear stage data obtained by a second sensor. (3) The vehicle control device according to (1) or (2), wherein the control unit is capable of setting a gain of the fluctuating torque in a first gear position to a first gain when the required torque in the transient state is regenerative torque, and setting a gain of the fluctuating torque in the first gear position to a second gain smaller than the first gain when the required torque in the transient state is powering torque. (4) The vehicle control device according to any one of (1) to (3), wherein the control unit is capable of determining whether or not the fluctuating torque needs to be added to the required torque based on a control flag input via an input unit provided in the vehicle, and is capable of deriving the target torque by adding the fluctuating torque to the required torque when the control flag indicates that the fluctuating torque needs to be added to the required torque.(5) A vehicle control device capable of controlling a vehicle driven by a motor, comprising: deriving a target torque by adding a periodically fluctuating torque to a required torque according to an acceleration request, and controlling the torque of the motor based on the derived target torque; and changing a gain of the fluctuating torque according to a gear position when the vehicle is in a transient state different from a steady state in which the acceleration and angular velocity are equal to or less than a predetermined value.

[0056] The control unit 20 shown in FIG. 1 can be implemented by circuitry 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). The at least one processor can be configured to perform all or a portion of the various functions of the control unit 20 shown in FIG. 1 by reading instructions from at least one non-transitory, tangible computer-readable medium. Such media can take various forms, including, but 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 or non-volatile memories. Volatile memories can include DRAM and SRAM. Non-volatile memories can include ROM and NVRAM. An ASIC is an integrated circuit (IC) specialized to perform all or a portion of the various functions of the control unit 20 shown in FIG. 1. An FPGA is an integrated circuit designed to be configurable after manufacture to perform all or part of the various functions of control unit 20 shown in FIG.

Claims

1. A vehicle control device capable of controlling a vehicle driven by a motor, comprising: a control unit capable of deriving a target torque by adding a periodically fluctuating torque to a required torque according to an acceleration request, and controlling the torque of the motor based on the derived target torque, wherein the control unit is capable of changing the gain of the fluctuating torque according to the gear stage when the vehicle is in a transient state other than a steady state in which the acceleration and angular velocity are below a predetermined value.

2. The vehicle control device according to claim 1, wherein the control unit is capable of determining whether the vehicle is in the steady state or the transient state based on acceleration data and angular velocity data obtained by a first sensor, and further capable of setting a gain for the torque fluctuation based on gear speed data obtained by a second sensor.

3. The vehicle control device according to claim 1, wherein the control unit is capable of setting a gain of the fluctuating torque in the first gear stage to a first gain when the required torque in the transient state is regenerative torque, and of setting a gain of the fluctuating torque in the first gear stage to a second gain smaller than the first gain when the required torque in the transient state is powering torque.

4. A vehicle control device as described in claim 1, wherein the control unit determines whether or not it is necessary to add the fluctuating torque to the required torque based on a control flag input via an input section provided in the vehicle, and when the control flag indicates that it is necessary to add the fluctuating torque to the required torque, it is possible to derive the target torque by adding the fluctuating torque to the required torque.

5. A vehicle control device capable of controlling a vehicle driven by a motor, comprising: deriving a target torque by adding a periodically varying variable torque to a required torque according to an acceleration request, and controlling the torque of the motor based on the derived target torque; and changing a gain of the variable torque according to the gear stage when the vehicle is in a transient state other than a steady state in which the acceleration and angular velocity are equal to or lower than a predetermined value.

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