Slip determination device and vehicle

Abstract

The invention provides a slip determination device and a vehicle. Provided is a slip determination device capable of determining whether or not a vehicle is slipping. A slip determination device according to one embodiment of the present disclosure is provided with: a motor control circuit capable of generating a first torque command value fluctuating at a predetermined frequency, and capable of determining the torque of a motor on the basis of the first torque command value and a second torque command value corresponding to a driving operation by a driver of a vehicle; and a determination circuit capable of detecting a fluctuation component of the frequency in the rotational speed of the motor and determining whether or not the vehicle is slipping on the basis of the fluctuation component.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a slip determination device that determines a slip of a vehicle and a vehicle that has such a slip determination device. BACKGROUND

[0002] A vehicle such as an automobile can slip, for example, depending on road conditions. For example, a technique is disclosed in Patent Literature 1 in which, in a case where a resonance frequency of a vibration generated by a drive system is a frequency that is in a predetermined resonance frequency band that indicates a slip state, a rotational speed of a motor is corrected.

[0003] PRIOR ART DOCUMENT PATENT LITERATURE Patent Literature 1: Japanese Patent Application Publication No. 2022-039447 SUMMARY

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION In a vehicle, it is desirable to be able to determine whether the vehicle is slipping, and it is desirable to be able to determine whether the vehicle is slipping effectively.

[0005] It is desirable to provide a slip determination device and a vehicle that can determine whether a vehicle is slipping effectively.

[0006] TECHNICAL SOLUTION A slip determination device of one embodiment of the present disclosure includes a motor control circuit and a determination circuit. The motor control circuit can generate a first torque command value that fluctuates at a predetermined frequency, and can determine a torque of a motor on the basis of the first torque command value and a second torque command value that corresponds to a driving operation of a driver of a vehicle. The determination circuit can detect a fluctuation component of the frequency in a rotational speed of the motor, and can determine whether the vehicle is slipping on the basis of the fluctuation component.

[0007] A vehicle of one embodiment of the present disclosure includes a motor, a motor control circuit, and a determination circuit. The motor can generate a driving force for running of the vehicle. The motor control circuit can generate a first torque command value that fluctuates at a predetermined frequency, and can determine a torque of the motor on the basis of the first torque command value and a second torque command value that corresponds to a driving operation of a driver of the vehicle. The determination circuit can detect a fluctuation component of the frequency in a rotational speed of the motor, and can determine whether the vehicle is slipping on the basis of the fluctuation component.

[0008] EFFECT OF THE INVENTION According to the slip determination device and the vehicle of one embodiment of the present disclosure, it is possible to determine whether a vehicle is slipping effectively. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a diagram illustrating an example of a vehicle of one embodiment of the present disclosure.

[0010] Figure 2 is a characteristic diagram showing an example of a sensitivity characteristic of an influence of a torque of the motor on a rotational speed of the motor. Figure 1

[0011] Figure 3 is a timing chart showing an example of an operation of the vehicle. Figure 1

[0012] Symbol explanation 1… vehicle, 11… battery, 12… electric power control device, 13… motor, 13A… rotational speed sensor, 14… drive system, 15… wheel, 16… driving operation section, 17… user interface, 20… control circuit, 21… torque command value generation section, 22… pulsation torque command value generation section, 23… motor torque command value generation section, 24… slip determination section, 100… slip determination device DETAILED DESCRIPTION

[0013] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0014] <EMBODIMENT> [Configuration example] Figure 1 is a diagram showing one configuration example of a vehicle 1 provided with a control device of one embodiment. The vehicle 1 is an electric vehicle, and is provided with a battery 11, an electric power control device 12, a motor 13, a drive system 14, a wheel 15, a driving operation section 16, a control circuit 20, and a user interface 17. The control circuit 20 and the user interface 17 constitute a slip determination device 100.

[0015] The battery 11 is configured to store electric power, and supplies direct-current electric power to the electric power control device 12. In addition, the battery 11 can store electric power supplied from the electric power control device 12.

[0016] The electric power control device 12 is configured to control electric power supplied to the motor 13. The electric power control device 12 is configured to include, for example, an inverter, and converts direct-current electric power supplied from the battery 11 into alternating-current electric power on the basis of a motor torque command value supplied from the control circuit 20, and supplies the alternating-current electric power to the motor 13. In addition, the electric power control device 12 can supply electric power supplied from the motor 13 to the battery 11.

[0017] ​​The motor 13 is configured to generate a driving force as mechanical energy based on alternating-current electric power supplied from the electric power control device 12. Then, the motor 13 transmits the driving force to the wheels 15 via the drive system 14. As a result, the vehicle 1 is able to travel based on the driving force. In addition, the motor 13 is also able to act as a generator that generates electric power based on mechanical energy supplied from the drive system 14, and is able to supply the generated alternating-current electric power to the electric power control device 12.

[0018] The motor 13 has a rotational speed sensor 13A. The rotational speed sensor 13A is configured to detect a rotational speed of the motor 13. Also, the rotational speed sensor 13A supplies data related to the detected rotational speed of the motor 13 to the control circuit 20.

[0019] The drive system 14 is configured to transmit the driving force supplied from the motor 13 to the wheels 15. The drive system 14 includes various shafts such as a reduction gear, a differential gear, a drive shaft, and the like, which are provided in a transmission path of the driving force from the motor 13 to the wheels 15.

[0020] The wheels 15 are drive wheels of the vehicle 1, and are configured to make the vehicle 1 travel on a road surface by rotating around a vehicle axis based on the driving force supplied from the drive system 14.

[0021] The driving operation section 16 includes a steering wheel, an accelerator pedal, a brake pedal, various levers, and the like, which are operated by a driver when the driver drives the vehicle 1.

[0022] The control circuit 20 is, for example, an ECU (Electronic Control Unit), and is configured using one or more processors, one or more memories, and the like. The control circuit 20 is able to act as a torque command value generation section 21, a pulsation torque command value generation section 22, a motor torque command value generation section 23, and a slip determination section 24 by executing software.

[0023] The torque command value generation section 21 is configured to generate a torque command value that shows a command value of a torque of the motor 13 based on an operation of an accelerator pedal of the driving operation section 16 by the driver. In addition, the torque command value generation section 21 supplies data related to the generated torque command value to the pulsation torque command value generation section 22.

[0024] The pulsating torque command value generation unit 22 is configured to generate a pulsating torque command value that fluctuates at a predetermined frequency f0. The pulsating torque command value generation unit 22 generates a pulsating torque command value with an amplitude corresponding to the torque command value generated by the torque command value generation unit 21. Specifically, the pulsating torque command value generation unit 22 generates the pulsating torque command value, for example, such that the amplitude of the pulsating torque command value fluctuation is approximately 10% of the torque command value. Furthermore, the pulsating torque command value generation unit 22 supplies data related to the amplitude of the generated pulsating torque command value to the slippage determination unit 24.

[0025] The motor torque command value generation unit 23 is configured to generate a motor torque command value that shows the torque of the motor 13 based on the torque command value generated by the torque command value generation unit 21 and the pulsating torque command value generated by the pulsating torque command value generation unit 22. Specifically, the motor torque command value generation unit 23 generates the motor torque command value by superimposing the torque command value generated by the torque command value generation unit 21 and the pulsating torque command value generated by the pulsating torque command value generation unit 22.

[0026] The slippage determination unit 24 is configured to detect the frequency fluctuation component f0 in the rotational speed of the motor 13 based on the detection result of the speed sensor 13A, and determine whether the vehicle 1 is slipping based on this fluctuation component. That is, since the pulsating torque command value fluctuates at frequency f0, the rotational speed of the motor 13 includes a frequency fluctuation component f0. The magnitude of this fluctuation component varies depending on the slippage state of the vehicle 1.

[0027] Figure 2 This is a graph illustrating an example of the sensitivity characteristics of a motor 13 in vehicle 1, showing the effect of the torque on the rotational speed of the motor 13. The horizontal axis represents frequency, and the vertical axis represents gain. Figure 2 In the diagram, characteristic W1, shown by a solid line, represents the characteristics of vehicle 1 in a non-slipping state, while characteristic W2, shown by a dashed line, represents the characteristics of vehicle 1 in a state where the coefficient of friction between wheel 15 and the road surface is zero and vehicle 1 is in a state of complete slippage.

[0028] In the non-slipping state of vehicle 1 (characteristic W1), resonance occurs at frequency f1. For example, since the drive shaft included in the drive system 14 has both elastic and damping components mechanically, torsional resonance may occur in the rotational direction of the drive shaft. Because vehicle 1 travels by rotating wheels 15 when it is not slipping, the mechanical load on the drive system 14 is relatively large. Therefore, as... Figure 2 As shown, the torsional natural frequency is a low frequency f1 (e.g., around 9Hz).

[0029] Furthermore, if vehicle 1 slips, the torsional natural frequency gradually increases from frequency f1 depending on the degree of slippage. That is, in vehicle 1, if the degree of slippage increases, the torsional natural frequency gradually increases because the mechanical load on the drive system 14 gradually decreases. Then, when vehicle 1 is in a state of complete slippage (characteristic W2), the torsional natural frequency becomes a high frequency f2 (e.g., around 28Hz).

[0030] In the frequency range higher than frequency f1 and lower than frequency f2, the gain of the sensitivity characteristic varies depending on the slippage state of vehicle 1. That is, the smaller the degree of slippage, the higher the gain, and the greater the degree of slippage, the lower the gain.

[0031] In vehicle 1, the frequency f0 of the pulsating torque command value fluctuation is set to a frequency within a certain range. Since the pulsating torque command value fluctuates at frequency f0, the rotational speed of motor 13 includes a fluctuation component at frequency f0. Figure 2 As shown, since the sensitivity characteristics change according to the slippage state of vehicle 1, the magnitude of the fluctuation component of the rotational speed of motor 13 also changes according to the slippage state of vehicle 1. Therefore, the slippage determination unit 24 can determine whether vehicle 1 is slipping based on the magnitude of the fluctuation component of the frequency f0.

[0032] Specifically, the slippage determination unit 24 generates a threshold based on data related to the amplitude of the pulsating torque command value supplied from the pulsating torque command value generation unit 22, as described below. Then, the slippage determination unit 24 determines whether the vehicle 1 is slipping by comparing the amplitude of the fluctuation component of the frequency f0 in the rotational speed of the motor 13 with the threshold.

[0033] The user interface 17 is configured to provide information to the driver using displays such as liquid crystal displays, various indicators, and speakers. The user interface 17 can notify the driver of the determination result of the skid determination unit 24.

[0034] Here, the torque command value generation unit 21, the pulsating torque command value generation unit 22, and the motor torque command value generation unit 23 of the control circuit 20 correspond to a specific example of the "motor control circuit" in one embodiment of this disclosure. The pulsating torque command value corresponds to a specific example of the "first torque command value" in one embodiment of this disclosure. The torque command value corresponds to a specific example of the "second torque command value" in one embodiment of this disclosure. The slippage determination unit 24 of the control circuit 20 corresponds to a specific example of the "determination circuit" in one embodiment of this disclosure. The user interface 17 corresponds to a specific example of the "user interface" in one embodiment of this disclosure. The motor 13 corresponds to a specific example of the "motor" in one embodiment of this disclosure. The drive system 14 corresponds to a specific example of the "drive system" in one embodiment of this disclosure. The wheel 15 corresponds to a specific example of the "wheel" in one embodiment of this disclosure. The frequency f1 corresponds to a specific example of the "first frequency" in one embodiment of this disclosure. The frequency f2 corresponds to a specific example of the "second frequency" in one embodiment of this disclosure.

[0035] [Actions and Functions] Next, the operation and function of vehicle 1 in this embodiment will be explained.

[0036] (Overall Action Summary) First, refer to Figure 1 The operation of vehicle 1 will be described. Battery 11 stores electricity and supplies DC power to power control device 12. Power control device 12 controls the power supplied to motor 13. Motor 13 generates driving force as mechanical energy based on AC power supplied from power control device 12. Speed ​​sensor 13A of motor 13 detects the speed of motor 13. In addition, motor 13 operates as a generator that generates electricity based on mechanical energy supplied from drive system 14, and supplies the generated AC power to power control device 12. In this case, power control device 12 supplies power from motor 13 to battery 11, and battery 11 stores the power supplied from power control device 12. Drive system 14 transmits the driving force supplied from motor 13 to wheels 15. Based on the driving force supplied from drive system 14, wheels 15 rotate around axles, causing vehicle 1 to travel on the road.

[0037] The torque command value generation unit 21 of the control circuit 20 generates a torque command value that displays the torque of the motor 13 based on the driver's operation of the accelerator pedal on the driving operation unit 16. The pulsating torque command value generation unit 22 generates a pulsating torque command value that fluctuates at a predetermined frequency f0. The motor torque command value generation unit 23 generates a motor torque command value that displays the torque of the motor 13 based on the torque command value generated by the torque command value generation unit 21 and the pulsating torque command value generated by the pulsating torque command value generation unit 22. The slippage determination unit 24 detects the frequency f0 fluctuation component in the rotational speed of the motor 13 based on the detection result of the speed sensor 13A, and determines whether the vehicle 1 is slipping based on the fluctuation component. The user interface 17 notifies the driver of the determination result of the slippage determination unit 24.

[0038] (Detailed actions) Figure 3 This is a diagram representing an example of the action of vehicle 1. Figure 3 (A) shows the torque of motor 13. Figure 3 (B) shows the acceleration of vehicle 1. Figure 3 (C) indicates the slippage rate. Figure 3 (D) shows the fluctuation component of the motor 13's rotational speed at frequency f0. The horizontal axis represents time. One mark on the horizontal axis represents 0.5 seconds.

[0039] In this example, the driver depresses the accelerator pedal, accelerating vehicle 1. The torque command value generation unit 21 gradually increases the torque command value based on the driver's operation of the accelerator pedal. The pulsating torque command value generation unit 22 generates a pulsating torque command value with an amplitude of approximately 10% of the torque command value and fluctuating at a frequency f0. The motor torque command value generation unit 23 generates a motor torque command value by superimposing the torque command value generated by the torque command value generation unit 21 and the pulsating torque command value generated by the pulsating torque command value generation unit 22. Based on this motor torque command value, the power control device 12 converts the DC power supplied from the battery 11 into AC power and supplies this AC power to the motor 13. The motor 13 generates a driving force as mechanical energy based on this AC power. Figure 3 As shown in (A), the torque of motor 13 increases while fluctuating at a frequency f0 over time. Accompanying this, as... Figure 3 As shown in (B), the acceleration of vehicle 1 increases.

[0040] The speed sensor 13A of motor 13 detects the speed of motor 13. The slippage determination unit 24, based on time-series data related to the speed of motor 13, extracts the fluctuation component of frequency f0 by performing processing such as bandpass filtering. Figure 3 As shown in (C), during the period earlier than time t1, the slippage rate is low enough that vehicle 1 does not slip.Figure 3 As shown in (D), when vehicle 1 is not slipping, the amplitude of the ripple component gradually increases as indicated by dashed lines W3 and W4. That is, the amplitude of the ripple component gradually increases in line with the gradually increasing pulsating torque command value.

[0041] Moreover, such as Figure 3 As shown in (C), the slippage rate begins to increase in the period later than time t1. That is, vehicle 1 begins to slip. Therefore, as Figure 3 As shown in (B), the acceleration of vehicle 1 stops increasing. Furthermore, the amplitude of the fluctuation component of the motor 13's rotational speed is smaller than the amplitude shown using dashed lines W3 and W4. For example, at time t2, the amplitude A2 of the fluctuation component is smaller than the amplitude A1 when vehicle 1 is not slipping. That is, as... Figure 2 As shown, the greater the degree of slippage, the lower the gain, and therefore the amplitude of the fluctuation component becomes smaller. The slippage determination unit 24 determines whether the vehicle 1 is slipping based on the amplitude of this fluctuation component.

[0042] Specifically, the slippage determination unit 24 estimates the amplitude of the fluctuation component of the motor 13's rotational speed when the vehicle 1 is not slipping, based on data related to the amplitude of the pulsating torque command value supplied from the pulsating torque command value generation unit 22. Then, the slippage determination unit 24 generates a threshold based on the estimated amplitude. For example, at time t2, the slippage determination unit 24 estimates the amplitude A1. Then, the slippage determination unit 24 sets a value slightly smaller than this amplitude A1 as the threshold.

[0043] The slippage determination unit 24 obtains, for example, the slippage determination unit 24. Figure 3 The amplitude of the fluctuation component is calculated by taking the difference between the maximum and minimum values ​​of the fluctuation component extracted using a bandpass filter, as shown in (D). Then, the slippage determination unit 24 determines whether the vehicle 1 is slipping by comparing the amplitude of this fluctuation component with a threshold. Specifically, if the amplitude of the fluctuation component is greater than the threshold, the slippage determination unit 24 determines that the vehicle 1 is not slipping. Conversely, if the amplitude of the fluctuation component is less than the threshold, the slippage determination unit 24 determines that the vehicle 1 is slipping.

[0044] The user interface 17 notifies the driver of the determination result from the slippage determination unit 24. Specifically, for example, if the vehicle 1 is slipping, the user interface 17 may illuminate an indicator or emit a predetermined sound. Upon receiving the notification that the vehicle 1 is slipping, the driver may, for example, reduce the amount of pressure applied to the accelerator pedal. Thus, since slippage can be suppressed in the vehicle 1, safe driving can be achieved.

[0045] Thus, the slippage determination device 100 includes: an electric motor control circuit (torque command value generation unit 21, pulsating torque command value generation unit 22, motor torque command value generation unit 23), which can generate a first torque command value (pulsating torque command value) that fluctuates at a predetermined frequency f0, and can determine the torque of the electric motor (motor 13) based on the first torque command value (pulsating torque command value) and a second torque command value (torque command value) corresponding to the driving operation of the driver of vehicle 1; and a determination circuit (slippage determination unit 24), which can detect the fluctuation component of frequency f0 in the rotational speed of the electric motor (motor 13), and can determine whether vehicle 1 is slipping based on the fluctuation component. Therefore, the slippage determination device 100 can effectively determine whether vehicle 1 is slipping.

[0046] That is, for example, as described in Patent Document 1, when determining whether vehicle 1 is slipping based on changes in resonant frequency, it may take a certain amount of time to detect the frequency change with high accuracy. On the other hand, in the slippage determination device 100, since the determination of whether vehicle 1 is slipping is based on the fluctuation component of frequency f0, changes in the magnitude of the fluctuation component can be detected in a short time. Therefore, in the slippage determination device 100, it is possible to effectively determine whether vehicle 1 is slipping.

[0047] Furthermore, in the slippage determination device 100, if the magnitude of the fluctuation component is smaller than a threshold, the determination circuit (slippage determination unit 24) can determine that the vehicle 1 is slipping. Therefore, the slippage determination device 100 can determine whether the vehicle 1 is slipping simply by comparing the magnitude of the fluctuation component with a threshold. Thus, the slippage determination device 100 can effectively determine whether the vehicle 1 is slipping.

[0048] Furthermore, in the slippage determination device 100, the motor control circuit (torque command value generation unit 21, pulsating torque command value generation unit 22, and motor torque command value generation unit 23) can generate a first torque command value in such a way that the amplitude of the first torque command value (pulsating torque command value) fluctuating at a frequency f0 corresponds to the amplitude of the second torque command value (torque command value), and the determination circuit (slippage determination unit 24) can generate a threshold corresponding to the amplitude of the first torque command value (pulsating torque command value). Therefore, in vehicle 1, for example, when the acceleration is small, the amplitude of the pulsating torque command value can be reduced, and when the acceleration is large, the amplitude of the pulsating torque command value can be increased. Thus, the amplitude of the pulsating torque command value can be set to an appropriate value. Moreover, even when the amplitude of the pulsating torque command value changes in vehicle 1, the threshold can still be set to an appropriate value. Therefore, in vehicle 1, it is possible to effectively determine whether vehicle 1 is slipping.

[0049] Furthermore, in the slippage detection device 100, frequency f0 is a frequency higher than the first frequency (frequency f1) and lower than the second frequency (frequency f2). The first frequency (frequency f1) is the torsional natural frequency of the drive system 14 that transmits the driving force of the electric motor (motor 13) to the wheel 15 when the vehicle 1 is not slipping. The second frequency (frequency f2) is the torsional natural frequency of the drive system 14 when the coefficient of friction between the wheel 15 of the vehicle 1 and the road surface is zero. Figure 2 As shown, within the frequency range of f1 to f2, the gain of the sensitivity characteristic varies depending on the slippage state of vehicle 1. For example, at frequencies higher than f2, the gain does not change depending on the slippage state of vehicle 1. Furthermore, frequencies lower than f1 are used for the movement of vehicle 1, and these are frequencies where a person is more likely to feel sway. Therefore, in the slippage determination device 100, the frequency f0 of the pulsating torque command value is set to a frequency higher than f1 and lower than f2. Thus, in the slippage determination device 100, since the gain of the sensitivity characteristic varies depending on the slippage state of vehicle 1, it is possible to determine whether vehicle 1 is slipping. Furthermore, in the slippage determination device 100, the torque fluctuation of motor 13 corresponding to the pulsating torque command value can be prevented from affecting the behavior of vehicle 1, making the torque fluctuation less noticeable to the driver. As a result, it is possible to effectively determine whether vehicle 1 is slipping.

[0050] Furthermore, the slippage detection device 100 also includes a user interface 17 that notifies the driver when the detection circuit (slippage detection unit 24) determines that the vehicle 1 is slipping. This allows the driver to more reliably determine whether the vehicle 1 is slipping. For example, a driver can generally sense the vehicle's driving status by feeling vibrations. However, in electric vehicles, compared to motor-driven vehicles, it is more difficult for the driver to determine whether the vehicle is slipping. In vehicle 1, since the user interface 17 notifies the driver when it is determined that the vehicle 1 is slipping, the driver can more reliably determine whether the vehicle 1 is slipping. Then, the driver can, for example, reduce the amount of pressure applied to the accelerator pedal. Thus, safe driving is achieved in vehicle 1.

[0051] [Effect] In this embodiment as described above, since it has a motor control circuit and a determination circuit, it is possible to effectively determine whether the vehicle is slipping. The motor control circuit can generate a first torque command value that fluctuates at a predetermined frequency, and can determine the torque of the motor based on the first torque command value and a second torque command value corresponding to the driver's driving operation. The determination circuit can detect the frequency fluctuation component in the motor's rotational speed, and can determine whether the vehicle is slipping based on the fluctuation component.

[0052] In this embodiment, when the magnitude of the fluctuation component is smaller than the threshold, the determination circuit can determine that vehicle 1 is skidding, thus effectively determining whether the vehicle is skidding.

[0053] In this embodiment, since the motor control circuit can generate the first torque command value in such a way that the amplitude of the frequency fluctuation of the first torque command value is the same as the amplitude of the second torque command value, and the determination circuit can generate a threshold corresponding to the amplitude of the first torque command value, it can effectively determine whether the vehicle is slipping.

[0054] In this embodiment, since the frequency is higher than the first frequency and lower than the second frequency, the first frequency is the torsional natural frequency of the drive system that transmits the driving force of the electric motor to the wheel 15 when the vehicle is not slipping, and the second frequency is the torsional natural frequency of the drive system when the coefficient of friction between the vehicle wheel and the road surface is zero, it is possible to effectively determine whether the vehicle is slipping.

[0055] The above describes the present invention through various embodiments, but the present invention is not limited to these embodiments and can be modified in various ways.

[0056] For example, in the above embodiment, the user interface 17 may illuminate an indicator or emit a predetermined sound when the vehicle 1 is skidding, but it is not limited to this. Various methods can be used to notify the driver that the vehicle 1 is skidding.

[0057] It should be noted that the effects described in this specification are merely exemplary and not limiting; other effects may also occur.

[0058] Furthermore, this disclosure can be made in the following ways. (1) A slippage detection device, comprising: An electric motor control circuit is capable of generating a first torque command value that fluctuates at a predetermined frequency, and of determining the torque of the electric motor based on the first torque command value and a second torque command value corresponding to the driver's driving operation; and The determination circuit is capable of detecting the frequency fluctuation component in the rotational speed of the electric motor, and is capable of determining whether the vehicle is slipping based on the fluctuation component. (2) According to the slippage determination device described in (1), wherein, If the magnitude of the fluctuation component is smaller than a threshold, the determination circuit can determine that the vehicle is skidding. (3) According to the slippage determination device described in (2), wherein, The motor control circuit can generate the first torque command value in such a way that the amplitude of the fluctuation of the first torque command value at the frequency is the amplitude corresponding to the second torque command value. The determination circuit can generate the threshold corresponding to the amplitude of the first torque command value. (4) According to any one of (1) to (3) the slip determination device, wherein, The frequency is higher than the first frequency and lower than the second frequency. The first frequency is the torsional natural frequency of the drive system that transmits the driving force of the electric motor to the wheels when the vehicle is not slipping. The second frequency is the torsional natural frequency of the drive system when the coefficient of friction between the vehicle's wheels and the road surface is zero. (5) According to any one of (1) to (4) the slip determination device, wherein, The slippage detection device also has a user interface, which notifies the driver when the detection circuit determines that the vehicle is slipping. (6) A vehicle that has: An electric motor is capable of generating driving force for the movement of a vehicle. An electric motor control circuit is capable of generating a first torque command value that fluctuates at a predetermined frequency, and of determining the torque of the electric motor based on the first torque command value and a second torque command value corresponding to the driving operation of the driver of the vehicle; and The determination circuit is capable of detecting the frequency fluctuation component in the rotational speed of the electric motor, and is capable of determining whether the vehicle is slipping based on the fluctuation component.

Claims

1. A slip determination device characterized by comprising: Possessing: a motor control circuit capable of generating a first torque command value that fluctuates at a predetermined frequency, and capable of determining a torque of a motor based on the first torque command value and a second torque command value corresponding to a driving operation of a driver of a vehicle; and a determination circuit capable of detecting a fluctuation component of the frequency in a rotational speed of the motor, and capable of determining whether the vehicle is slipping based on the fluctuation component.

2. The slip determination device according to claim 1, characterized in that in a case where a magnitude of the fluctuation component is smaller than a threshold value, the determination circuit is capable of determining that the vehicle is slipping.

3. The slip determination device according to claim 2, characterized in that the motor control circuit is capable of generating the first torque command value in a manner that an amplitude at which the first torque command value fluctuates at the frequency becomes an amplitude corresponding to the second torque command value, the determination circuit is capable of generating the threshold value corresponding to the amplitude of the first torque command value.

4. The slip determination device according to claim 1, characterized in that the frequency is a frequency that is higher than a first frequency and lower than a second frequency, the first frequency is a torsional natural frequency of a drive system that transmits a driving force of the motor to a wheel in a case where the vehicle is not slipping, the second frequency is a torsional natural frequency of the drive system in a case where a friction coefficient between the wheel of the vehicle and a road surface is zero.

5. The slip determination device according to claim 1, characterized in that the slip determination device further possesses a user interface that notifies the driver in a case where the determination circuit determines that the vehicle is slipping.

6. A vehicle characterized by comprising: Possessing: a motor capable of generating a driving force for running of a vehicle; a motor control circuit capable of generating a first torque command value that fluctuates at a predetermined frequency, and capable of determining a torque of the motor based on the first torque command value and a second torque command value corresponding to a driving operation of a driver of the vehicle; and a determination circuit capable of detecting a fluctuation component of the frequency in a rotational speed of the motor, and capable of determining whether the vehicle is slipping based on the fluctuation component.

Images