vehicle

Abstract

A vehicle is provided with a main motor for driving and an electronic control device for controlling the main motor. The electronic control device is configured to extract vibration data of a specified frequency band including the resonance frequency of a drive system including the main motor from time series data of the rotation speed of the main motor. The electronic control device is configured to reduce the output torque upper limit value of the main motor from a normal upper limit value to a first upper limit value lower than the normal upper limit value if the magnitude of the vibration obtained from the extracted vibration data exceeds a first threshold value. Furthermore, the electronic control device is configured to reduce the output torque upper limit value to a second upper limit value lower than the first upper limit value if the magnitude of the vibration exceeds a second threshold value greater than the first threshold value.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a vehicle equipped with an electric motor for traveling. Background Art

[0002] The vehicle will vibrate while driving. In particular, when the frequency of the load received from the road surface is close to the resonant frequency of the vehicle body, the vibration of the vehicle body becomes larger. For example, Japanese Patent Laid-Open 2018-24278 and Japanese Patent Laid-Open 2020-171067 disclose a technology that uses the vibration amplitude of the rotation speed of the wheel to determine whether the vehicle body resonates. The automobile disclosed in Japanese Patent Laid-Open 2018-24278 is equipped with a filter processing unit and a determination unit, and the filter processing unit applies a bandpass filter containing the resonant frequency region of the vehicle to the time series data of the rotation speed. When the cumulative value of the absolute value of each of the filter processing values ​​of a specified number from the filter processing unit is greater than or equal to the first threshold, the determination unit determines that resonance occurs. In order to protect the components of the vehicle from the influence of vibration, the automobile disclosed in Japanese Patent Laid-Open 2018-24278 and Japanese Patent Laid-Open 2020-171067 limits the driving force when it is determined that resonance occurs. Summary of the invention

[0003] When the driving force drops sharply and suddenly, there is a risk of giving the occupants a sense of discomfort. This specification provides a technique for suppressing vibration and reducing the sense of discomfort given to the occupants.

[0004] The vehicle disclosed in this specification is equipped with a main motor for driving and an electronic control device for controlling the main motor. The electronic control device is configured to extract vibration data of a specified frequency band from the time series data of the rotation speed of the main motor, and the specified frequency band includes the resonant frequency of the drive system including the main motor. The electronic control device is configured to reduce the output torque upper limit value of the main motor from a normal upper limit value to a first upper limit value lower than the normal upper limit value if the magnitude of the vibration obtained from the extracted vibration data exceeds a first threshold value. Furthermore, the electronic control device is configured to reduce the output torque upper limit value from the first upper limit value to a second upper limit value lower than the first upper limit value if the magnitude of the vibration exceeds a second threshold value greater than the first threshold value.

[0005] That is, the electronic control device reduces the output torque upper limit of the main motor in two stages according to the size of the vibration data. By reducing the output torque upper limit of the main motor, the vibration can be suppressed. In addition, since the output torque upper limit of the main motor is reduced in two stages, the discomfort of the passengers caused by the rapid reduction of the output torque upper limit can be reduced. In addition, if the size of the vibration is reduced due to the first stage reduction of the output torque upper limit (from the normal upper limit to the first upper limit), there is no need to perform the second stage reduction (from the first upper limit to the second upper limit).

[0006] The magnitude of the vibration can also be represented by the cumulative value or moving average of the amplitude in the latest specified period in the vibration data. Alternatively, the magnitude of the vibration can also be represented by the peak value in the frequency characteristics of the vibration data or the cumulative value of the amplitude in the frequency characteristics. By using the cumulative value or moving average of the amplitude in the specified period to measure the magnitude of the vibration, the tendency of the amplitude to change over time can be accurately grasped. "Amplitude" can be expressed as a double amplitude (peak to peak) or as a single amplitude (zero to peak). When measuring the amplitude with a single amplitude with a positive or negative sign, the cumulative value of the absolute value of the amplitude in the vibration data or the moving average of the absolute value can be used.

[0007] The vehicle may also be equipped with an auxiliary motor for driving. The resonant frequency of the auxiliary drive system including the auxiliary motor may also be included in a prescribed frequency band, and the prescribed frequency band includes the resonant frequency of the drive system including the main motor. The electronic control device may also be configured to: if the magnitude of the vibration exceeds the first threshold value, the output torque upper limit value of the main motor is reduced from the normal upper limit value to the first upper limit value, and the output torque upper limit value of the auxiliary motor is reduced from the normal upper limit value of the auxiliary motor to the first upper limit value of the auxiliary motor lower than the normal upper limit value of the auxiliary motor. The electronic control device may also be configured to: if the magnitude of the vibration exceeds the second threshold value, the output torque upper limit value is reduced from the first upper limit value to the second upper limit value, and the output torque upper limit value of the auxiliary motor is reduced from the first upper limit value of the auxiliary motor to the second upper limit value of the auxiliary motor lower than the first upper limit value of the auxiliary motor.

[0008] When the resonant frequency of the auxiliary motor is close to the resonant frequency of the main motor, when the vibration of the drive system including the main motor is large, the vibration of the auxiliary drive system also becomes large. Based on the vibration data of the main motor, the output torque upper limit value of not only the main motor but also the auxiliary motor is reduced, thereby being able to more effectively suppress vibration.

[0009] The resonant frequency of the auxiliary drive system may also be outside the resonant frequency of the drive system including the main motor. The electronic control device may also be configured to, if the magnitude of the vibration of the drive system including the main motor exceeds a first threshold value, reduce the upper limit value of the output torque of the main motor from a normal upper limit value to a first upper limit value, and reduce a first ratio and increase a second ratio, wherein the first ratio is a ratio of the output torque of the main motor to a target total output torque of the vehicle, and the second ratio is a ratio of the output torque of the auxiliary motor to a target total output torque of the vehicle.

[0010] When the resonant frequency of the auxiliary drive system deviates from the resonant frequency of the drive system including the main motor, the vibration of the auxiliary drive system will not increase even if the vibration of the drive system including the main motor increases. By increasing the proportion of the output torque of the auxiliary motor with small vibration, the vibration of the drive system including the main motor can be suppressed, and the output reduction of the main motor can be compensated.

[0011] The following describes the details and further improvements of the technology disclosed in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Hereinafter, features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described with reference to the accompanying drawings, in which like reference numerals denote like components, and in which:

[0013] Figure 1 is a block diagram of a vehicle according to the first embodiment.

[0014] Figure 2 This is a flowchart of the output limitation process implemented by the controller.

[0015] Figure 3 This is an example of a time chart of the vibration data of the rotation speed, the amplitude integrated value, and the output torque upper limit value.

[0016] Figure 4 is a block diagram of a vehicle according to the second embodiment.

[0017] Figure 5 is a block diagram of a vehicle according to the third embodiment. DETAILED DESCRIPTION

[0018] (First Embodiment) A vehicle 2 of a first embodiment is described with reference to the drawings. Figure 1 2 is a block diagram of a driving system of vehicle 2. Figure 1 The dashed arrow line in FIG. 2 represents a signal line. The vehicle 2 is equipped with a main motor 3 for traveling. The main motor 3 drives the front wheels 5. The output torque of the main motor 3 is transmitted to the front wheels 5 via the front wheel differential gear 4 and the front wheel axle 9.

[0019] In addition to the main motor 3, the vehicle 2 is also equipped with an inverter 6, a battery 7, and a controller 10. The output power (DC power) of the battery 7 is converted into AC power by the inverter 6 and supplied to the main motor 3. The inverter 6 is controlled by the controller 10. The main motor 3 is equipped with a rotation speed sensor 8 for measuring the rotation speed of the main motor 3. In addition, a current sensor not shown in the figure is provided at the AC end of the inverter 6. The controller 10 is, for example, an electronic control device equipped with a processor and a memory, and controls the inverter 6 based on the measured value of the current sensor and the measured value of the rotation speed sensor 8 so that the output torque of the main motor 3 follows the target torque.

[0020] The controller 10 also performs a process for suppressing vibration of the drive system including the main motor 3. Here, the drive system including the main motor 3 refers to the main motor 3, the power transmission path (front wheel differential gear 4 and front wheel axle 9) to the drive wheel (front wheel 5) driven by the main motor 3, and the structure supporting them.

[0021] When the vehicle 2 is traveling, various loads are applied to the vehicle body in accordance with the unevenness of the road surface. When the frequency of the load applied to the vehicle body is close to the resonant frequency of the drive system including the main motor 3, the vibration of the drive system becomes larger, the load applied to the structure of the drive system becomes larger, and the passengers feel uncomfortable. On the other hand, the vibration received by the vehicle 2 from the road surface is presented in the measurement data of the rotation speed sensor 8. The controller 10 extracts vibration data of a specified frequency band (resonance frequency band) containing the resonant frequency of the drive system including the main motor 3 from the measurement data of the rotation speed sensor 8 (time series data of the rotation speed). In other words, the controller 10 removes the components of the frequency band other than the resonant frequency band from the time series data of the rotation speed and extracts the vibration data of the resonant frequency band. The vibration data of the resonant frequency band is obtained by applying a bandpass filter to the time series data of the rotation speed. The bandpass filter is set to pass the vibration components of the resonant frequency band and remove the vibration components of the frequency band other than the resonant frequency band.

[0022] When the frequency of the vibration received from the road surface is close to the resonant frequency of the drive system including the main motor 3, the magnitude of the vibration obtained from the vibration data increases. If the magnitude of the vibration obtained from the vibration data exceeds the first threshold value, the controller 10 reduces the output torque upper limit value of the main motor 3 from the normal upper limit value to the first upper limit value. The controller 10 limits the output of the inverter 6 so that the output of the main motor 3 does not exceed the set output torque upper limit value. By reducing the output torque upper limit value of the main motor 3, the increase of the vibration of the drive system including the main motor 3 can be suppressed.

[0023] The so-called "magnitude of vibration" can be, specifically, the cumulative value or moving average of the amplitude in the latest specified period in the vibration data (time series data of the rotation speed after applying the bandpass filter). Alternatively, the so-called "magnitude of vibration" can also be the peak value in the frequency characteristics of the vibration data, or the cumulative value of the amplitude in the frequency characteristics. If the high-speed Fourier transform is applied to the vibration data, the frequency characteristics of the vibration data are obtained.

[0024] The amplitude obtained from the rotation speed sensor 8 is preferably measured as a double amplitude (peak to peak), but may also be measured as a single amplitude (zero to peak). When a single amplitude with a positive or negative sign is measured, the cumulative value or moving average of the absolute value of the single amplitude is used as an index for measuring the magnitude of the vibration.

[0025] If the magnitude of the vibration exceeds the second threshold value after exceeding the first threshold value, the controller 10 reduces the output torque upper limit value to a second upper limit value lower than the first upper limit value. The second threshold value is a value greater than the first threshold value. That is, the controller 10 reduces the output torque upper limit value of the main motor 3 in two stages according to the magnitude of the vibration. When the output torque upper limit value drops sharply, there is a risk of giving the passengers a sense of discomfort. By reducing the output torque upper limit value of the main motor 3 in two stages, the discomfort given to the passengers can be reduced.

[0026] exist Figure 2 FIG. 1 is a flowchart showing the processing (output restriction processing) performed by the controller 10. Figure 2 The processing of the controller 10 is described with reference to the flowchart of FIG.

[0027] The controller 10 repeats the operation at a certain period. Figure 2 The controller 10 first obtains the rotation speed from the rotation speed sensor 8 (step S11). The controller 10 also stores the rotation speed obtained in the past. That is, the controller 10 obtains the time series data of the rotation speed. Every time step S11 is implemented, the time series data of the rotation speed is updated to the latest data column.

[0028] The controller 10 applies a bandpass filter to the latest time series data of the rotation speed (step S12). The bandpass filter retains the vibration components of a predetermined frequency band (resonance frequency band) including the resonance frequency of the drive system including the main motor 3, and removes the vibration components of the frequencies outside the resonance frequency band. The time series data of the rotation speed after the bandpass filter is applied is called vibration data.

[0029] Next, the controller 10 calculates the cumulative value of the vibration data of the latest specified period (step S13). As described above, when the vibration data is represented by a single amplitude with a positive or negative sign, the controller 10 accumulates the absolute value of each amplitude data of the specified period. The specified period can be set arbitrarily. The cumulative value of the vibration data becomes an indicator for measuring the magnitude of the vibration.

[0030] Next, the controller 10 compares the integrated value with the second threshold value (step S14). The controller 10 compares the integrated value with the first threshold value in step S16 described later. The second threshold value is set to a value larger than the first threshold value.

[0031] When the drive system including the main motor 3 vibrates violently, the cumulative value gradually increases with the passage of time. Therefore, before the branch judgment of step S14 becomes "yes", the branch judgment of step S16 becomes "yes". In the case where the branch judgment of step S16 is "yes" (that is, when the cumulative value exceeds the first threshold), the controller 10 changes the output torque upper limit value of the main motor 3 from the normal upper limit value to the first upper limit value lower than it (step S16: yes, S17), and in addition, when the vehicle 2 has started to travel, the output torque upper limit value of the main motor 3 is set to the normal upper limit value.

[0032] When the integrated value exceeds the second threshold value (step S14: YES), the controller 10 changes the output torque upper limit value of the main motor 3 to the second upper limit value (step S15). The second upper limit value is set to a value lower than the first upper limit value.

[0033] Through the processing of steps S14 to S17 , as the integrated value increases, the output torque upper limit value of the main motor 3 decreases in two stages from the normal upper limit value to the first upper limit value and further from the first upper limit value to the second upper limit value.

[0034] As the vibration of the vehicle body becomes smaller, the cumulative value gradually becomes smaller. When the cumulative value drops below the recovery threshold, the controller 10 restores the output torque upper limit value of the main motor 3 to the normal upper limit value (step S18: yes, S19). The recovery threshold is set to a value lower than the first threshold. The purpose of setting a recovery threshold lower than the first threshold is to prevent the output torque upper limit value of the main motor 3 from fluctuating between the normal upper limit value and the first upper limit value near the first threshold. Instead of setting the recovery threshold (or while setting the recovery threshold), when the cumulative value continuously drops below the first threshold for more than the specified recovery judgment period, the output torque upper limit value is restored to the normal upper limit value.

[0035] exist Figure 3 An example of a time chart showing vibration data, amplitude cumulative value, and output torque upper limit value is shown in FIG. Figure 3The graph (A) is a graph of vibration data. In other words, Figure 3 The graph (A) of represents the data after a bandpass filter is applied to the time series data of the rotation speed. Figure 3 The graph (A) does not include a DC component, and the vibration vibrates up and down around zero. As described above, the time series data (vibration data) of the rotation speed after the bandpass filter is applied only includes vibration components in the resonance frequency band.

[0036] Figure 3 The graph (B) is a graph of the cumulative value of the amplitude in the latest predetermined period in the vibration data. Since it is the cumulative value in the predetermined period, as the amplitude decreases, the cumulative value also gradually decreases. Figure 3 The graph (C) is a time chart of the output torque upper limit value of the main motor 3. The output torque upper limit value of the main motor 3 is initially set to a normal upper limit value.

[0037] At time T1, the cumulative value of the amplitude of the vibration data exceeds the first threshold value. The controller 10 reduces the output torque upper limit value of the main motor 3 from the normal upper limit value to the first upper limit value at time T1. At time T2, the cumulative value exceeds the second threshold value. The controller 10 reduces the output torque upper limit value of the main motor 3 from the first upper limit value to the second upper limit value. The second upper limit value is set to a value lower than the first upper limit value.

[0038] After time T3, the amplitude gradually decreases and the integrated value also decreases. At time T4, the integrated value drops below the recovery threshold. At time T4, the controller 10 recovers the output torque upper limit value of the main motor 3 to the normal upper limit value.

[0039] The vehicle 2 of the first embodiment reduces the upper limit of the output torque of the main motor 3 in two stages according to the magnitude of the vibration of the drive system including the main motor 3. By reducing the upper limit of the output torque in two stages, the vibration of the drive system can be suppressed and the discomfort given to the passengers can be reduced.

[0040] In addition, after time T1 and before the cumulative value exceeds the second threshold, the cumulative value becomes smaller, and when it drops below the recovery threshold, the controller 10 recovers the output torque upper limit value of the main motor 3 from the first upper limit value to the normal upper limit value. Reducing the output torque upper limit value in two stages according to the magnitude of the vibration has the following advantages: when the vibration can be suppressed by reducing the output torque upper limit value in one stage, there is no need to perform a second stage of reduction.

[0041] (Second embodiment) Figure 4, a block diagram of a vehicle 2a of the second embodiment is shown. The vehicle 2a of the second embodiment is equipped with a sub-motor 13 in addition to the main motor 3. The sub-motor 13 drives the front wheel 5 together with the main motor 3. The output torque of the sub-motor 13 and the output torque of the main motor 3 are synthesized by the gear set 19 and transmitted to the front wheel differential gear 4. The sub-inverter 16 converts the DC power of the battery 7 into AC power and supplies it to the sub-motor 13. The controller 10a controls the inverter 6 and the sub-inverter 16.

[0042] The auxiliary motor 13 drives the front wheel 5 together with the main motor 3. The auxiliary motor 13 and the main motor 3 are housed in a frame. Therefore, the main motor 3 and the auxiliary motor 13 constitute a drive system. The drive system including the main motor 3 is equivalent to the drive system including the auxiliary motor 13. Therefore, the resonance frequency of the drive system including the main motor 3 is the same as the resonance frequency of the drive system including the auxiliary motor 13. Therefore, when the vibration component of the rotation speed of the main motor 3 becomes larger, the vibration component of the rotation speed of the auxiliary motor 13 also becomes larger.

[0043] In the case of the vehicle 2a of the second embodiment, the controller 10a applies a bandpass filter to the time series data of the rotation speed of the main motor 3 to obtain vibration data of the resonance frequency band. If the magnitude of the vibration obtained from the vibration data exceeds the first threshold value, the controller 10a reduces the output torque upper limit value of the main motor 3 from the normal upper limit value to the first upper limit value, and reduces the output torque upper limit value of the auxiliary motor 13 (auxiliary motor output torque upper limit value) from the auxiliary motor normal upper limit value to the auxiliary motor first upper limit value. If the magnitude of the vibration exceeds the second threshold value, the controller 10a reduces the output torque upper limit value of the main motor 3 to the second upper limit value, and reduces the auxiliary motor output torque upper limit value to the auxiliary motor second upper limit value lower than the auxiliary motor first upper limit value. For the vehicle 2a of the second embodiment, the vibration of the auxiliary motor 13 can also be effectively suppressed.

[0044] The maximum output of the auxiliary motor 13 is less than or equal to the maximum output of the main motor 3, and the influence of the vibration of the auxiliary motor 13 is smaller than the influence of the vibration of the main motor 3. Therefore, by measuring the magnitude of the vibration based on the time series data of the rotation speed of the main motor 3, the vibration of the drive system can be accurately grasped.

[0045] (Third embodiment) Figure 5, a block diagram of a vehicle 2b of the third embodiment is shown. The vehicle 2b of the third embodiment is equipped with a sub-motor 23 in addition to the main motor 3. The sub-motor 23 drives the rear wheel 25. The output torque of the sub-motor 23 is transmitted to the rear wheel 25 via the rear wheel differential gear 24 and the rear wheel axle 29. The sub-inverter 26 converts the DC power of the battery 7 into AC power and supplies it to the sub-motor 23. The controller 10b controls the inverter 6 and the sub-inverter 26.

[0046] The auxiliary motor 23 is arranged at the rear of the vehicle body, and is separated from the main motor 3 arranged at the front of the vehicle body. The drive system including the auxiliary motor 23 (auxiliary motor drive system) is the auxiliary motor 23, the power transmission path (rear wheel differential gear 24 and rear wheel axle 29) from the auxiliary motor 23 to the drive wheel (rear wheel 25), and the structure supporting them. The resonant frequency of the auxiliary motor drive system is outside the resonant frequency band described above (the frequency band including the resonant frequency of the drive system including the main motor 3). Therefore, even if the frequency of the vibration received from the road surface is included in the resonant frequency band and the vibration of the structure of the drive system including the main motor 3 increases, the vibration of the auxiliary motor drive system will not increase.

[0047] Therefore, if the magnitude of the vibration obtained from the vibration data of the main motor 3 exceeds the first threshold value, the controller 10b reduces the upper limit value of the output torque of the main motor 3 from the normal upper limit value to the first upper limit value, and reduces the ratio of the output torque of the main motor 3 to the target total output torque of the vehicle 2b, and increases the ratio of the output torque of the auxiliary motor 23 to the target total output torque of the vehicle 2b. More precisely, if the magnitude of the vibration obtained from the vibration data of the main motor 3 exceeds the first threshold value, the controller 10b reduces the ratio of the output torque of the main motor 3 to the target total output torque of the vehicle 2b to a ratio lower than the ratio of the output torque before the magnitude of the vibration exceeds the first threshold value. At the same time, the controller 10b increases the ratio of the output torque of the auxiliary motor 23 to the target total output torque of the vehicle 2b to a ratio higher than the ratio of the output torque before the magnitude of the vibration exceeds the first threshold value.

[0048] When the output torque upper limit of the main motor 3 is reduced to the first upper limit, the maximum output of the main motor 3 decreases. By increasing the ratio of the output torque of the auxiliary motor 23, the insufficient output torque of the main motor 3 can be compensated. Since the resonance frequency of the auxiliary motor drive system is outside the resonance frequency band, when the vibration of the drive system including the main motor 3 increases, the vibration of the drive system including the auxiliary motor 23 does not increase. Even if the ratio of the output torque of the auxiliary motor 23 is increased, the vibration of the entire vehicle body will not increase.

[0049] The following describes the points of attention related to the technology described in the embodiment. As an indicator representing the magnitude of the vibration, the moving average of the amplitude of the latest specified period in the vibration data can also be used. Alternatively, as an indicator representing the magnitude of the vibration, the peak value in the frequency characteristics of the vibration data, or the cumulative value of the amplitude in the frequency characteristics can also be used. If a high-speed Fourier transform is applied to the time series data of the rotation speed after applying a bandpass filter, the frequency characteristics of the vibration data are obtained. Alternatively, after applying a high-speed Fourier transform to the time series data of the rotation speed, the frequency characteristics of the resonance frequency band are extracted, and the frequency characteristics of the vibration data are also obtained. In this case, a bandpass filter is not required.

[0050] By using the cumulative value or moving average of the amplitude during the latest specified period as an indicator of the magnitude of the vibration, although the instantaneous change of the amplitude cannot be grasped, the tendency of the amplitude to change over time can be accurately grasped. In addition, by using the cumulative value or moving average, the change in the magnitude of the vibration over time becomes slow. It takes a corresponding amount of time from the time when the magnitude of the vibration exceeds the first threshold until it exceeds the second threshold. The situation in which the upper limit value of the output torque drops from the normal upper limit value to the second upper limit value in a short time is avoided. That is, a sharp change in the upper limit value of the output torque is avoided.

[0051] According to the technology disclosed in this specification, vibration can be suppressed by reducing the output torque upper limit value in two stages. The vibration suppression technology disclosed in this specification is advantageous in terms of both quality and cost compared to the technology of suppressing vibration by adding some parts.

[0052] The specific examples of the present invention are described in detail above, but these are only examples and do not limit the scope of the claims of the present invention. The technology described in the claims includes various deformations and changes to the specific examples shown above. The technical elements described in this specification or the drawings can exert the usefulness of the technology alone or in various combinations, and are not limited to the combinations recorded in the claims at the time of application. In addition, the technology shown by example in this specification or the drawings can achieve multiple purposes at the same time, but as long as one of the purposes is achieved, it itself has technical usefulness.

Claims

1. A vehicle, characterized in that: include: The main electric motor for driving; Auxiliary motor for driving; as well as An electronic control device for controlling the main motor and the auxiliary motor, wherein the electronic control device is configured as follows: Extracting vibration data of a predetermined frequency band from the time series data of the rotation speed of the main motor, wherein the predetermined frequency band includes: a resonance frequency of a drive system including the main motor, and a sub-motor resonance frequency of a sub-drive system including the sub-motor, If the magnitude of the vibration obtained from the vibration data exceeds a first threshold value, the output torque upper limit value of the main motor is reduced from a normal upper limit value to a first upper limit value lower than the normal upper limit value, and the output torque upper limit value of the sub-motor is reduced from the sub-motor normal upper limit value to a sub-motor first upper limit value lower than the sub-motor normal upper limit value, If the magnitude of the vibration exceeds a second threshold value that is larger than the first threshold value, the output torque upper limit value is reduced from the first upper limit value to a second upper limit value that is lower than the first upper limit value, and the output torque upper limit value of the sub-motor is reduced from the first upper limit value of the sub-motor to a second upper limit value of the sub-motor that is lower than the first upper limit value of the sub-motor.

2. The vehicle according to claim 1, characterized in that The maximum output of the auxiliary motor is less than or equal to the maximum output of the main motor.

3. The vehicle according to claim 1 or 2, characterized in that: The magnitude of the vibration is represented by an integrated value or a moving average of the amplitudes in the latest predetermined period in the vibration data.

4. The vehicle according to claim 1 or 2, characterized in that: The magnitude of the vibration is represented by a peak value in the frequency characteristics of the vibration data or a cumulative value of the amplitude in the frequency characteristics.

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