JP7548832B2 - MOTOR CONTROL DEVICE AND MOTOR CONTROL METHOD - Google Patents

Description

The present invention relates to a motor control device and a motor control method.

Conventionally, there have been technologies for vehicle control that deal with abnormalities in rotation speed such as slippage. For example, there are technologies equipped with electric brake systems and technologies for controlling the drive motor as described in Patent Document 1.

International Publication No. 2014/020813

However, in vehicles where the drive torque of multiple wheels can be controlled individually, such as when the wheels are driven by in-wheel motors, there is room for improvement in the control when recovering from an abnormal rotation speed state.

The present invention has been made in consideration of the above, and aims to provide a motor control device and a motor control method that can properly recover from an abnormal rotation speed state.

In order to solve the above-mentioned problems and achieve the object, the motor control device according to the present invention includes a determination unit and a motor control unit. In a vehicle in which a plurality of wheels are driven by different motors, the determination unit determines an abnormal rotation speed state for each motor based on the rotation acceleration of the motor. The motor control unit performs return control for returning the motor determined by the determination unit to be in the abnormal rotation speed state from the abnormal rotation speed state. The determination unit determines that the motor is in a spin state when the rotation acceleration is equal to or greater than a first threshold value, and determines that the motor is in a slip state when the rotation acceleration is less than the first threshold value and equal to or greater than a second threshold value lower than the first threshold value. The motor control unit differentiates the content of the return control when the motor is determined to be in the spin state from that when the motor is determined to be in the slip state.

The present invention makes it possible to properly recover from an abnormal rotation speed state.

FIG. 1A is a diagram illustrating an example of the configuration of a vehicle according to an embodiment. FIG. 1B is a diagram showing an overview of a motor control method according to an embodiment. FIG. 2 is a block diagram illustrating an example of the configuration of the motor control device according to the embodiment. FIG. 3 shows an example of map information. FIG. 4 is an explanatory diagram of the return control in a slip state. FIG. 5 is a diagram showing the torque redistribution process in a spin state. FIG. 6 is a diagram showing the torque redistribution process in a slip state. FIG. 7 is a flowchart showing a processing procedure of the processing executed by the motor control device according to the embodiment. FIG. 8 is a flowchart showing a processing procedure of the processing executed by the motor control device according to the embodiment. FIG. 9 is a flowchart showing a processing procedure of the processing executed by the motor control device according to the embodiment. FIG. 10 is a diagram showing the process of correcting the map information.

Below, embodiments of the motor control device and motor control method disclosed in the present application will be described in detail with reference to the attached drawings. Note that the present invention is not limited to the embodiments described below.

First, an overview of the motor control method according to the embodiment will be described using Figures 1A and 1B. Figure 1A is a diagram showing an example of the configuration of a vehicle according to the embodiment. Figure 1B is a diagram showing an overview of the motor control method according to the embodiment. The motor control method according to the embodiment is executed by a motor control device 1 mounted on a vehicle C shown in Figure 1A. As shown in Figure 1A, the vehicle C is a vehicle equipped with motors Mfl, Mfr, Mrl, and Mrr, which are in-wheel motors that drive the wheels, on each wheel. Note that, hereinafter, when there is no particular distinction between the motors Mfl, Mfr, Mrl, and Mrr, they may be collectively referred to as motor M.

In the motor control method according to the embodiment, first, an abnormal rotation speed state is determined for each motor M based on the rotation acceleration of the motor M. Specifically, in the motor control method according to the embodiment, the abnormal rotation speed state is determined to be a free-spin state or a slip state.

The spinning state refers to a state in which the wheels of vehicle C are not in contact with the ground due to unevenness of the road surface, as shown in FIG. 1B. More specifically, the spinning state refers to a state in which the coefficient of friction with the road surface is approximately zero.

The slip state refers to a state in which vehicle C is traveling on a frozen road surface and the wheels are not gripping the road (are not moving forward at all) regardless of the state of contact with the ground, as shown in FIG. 1B. More specifically, the slip state refers to a state in which the coefficient of friction with the road surface is extremely low.

Focusing on these characteristics, the motor control method according to the embodiment refers to map information 31 (see FIG. 3) described below, and determines that the motor is in a spinning state when the rotational acceleration is equal to or greater than a first threshold value TH1 (see FIG. 3). The motor control method according to the embodiment also determines that the motor is in a slipping state when the rotational acceleration is less than the first threshold value TH1 and equal to or greater than a second threshold value TH2 (see FIG. 3) that is lower than the first threshold value TH1.

In the motor control method according to the embodiment, if it is determined that the motor is in a spin state, recovery control for spin is performed to recover the motor from the spin state, and if it is determined that the motor is in a slip state, recovery control for slip is performed to recover the motor from the slip state.

In other words, in the motor control method according to the embodiment, the content of the return control is different depending on whether the motor is determined to be in a free-spin state or a slip state. As a result, the motor control method according to the embodiment can perform return control suitable for a free-spin state, and can also perform return control suitable for a slip state. Therefore, the motor control method according to the embodiment can properly return from an abnormal rotation speed state.

Details of the recovery control for spin and slip will be described later in Figure 2 and subsequent pages.

Next, the configuration of the motor control device 1 according to the embodiment will be described with reference to FIG. 2. FIG. 2 is a block diagram showing an example of the configuration of the motor control device 1 according to the embodiment. As shown in FIG. 2, the motor control device 1 includes a control unit 2 and a storage unit 3. In addition, the motor control device 1 is connected to a rotation speed sensor 100.

The rotation speed sensor 100 is a sensor that detects the rotation speed of each motor M.

Here, the motor control device 1 includes, for example, a computer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), flash memory, input/output ports, and various other circuits.

The computer's CPU functions as the acquisition unit 21, determination unit 22, and motor control unit 23 of the control unit 2, for example, by reading and executing a program stored in the ROM.

In addition, at least one or all of the acquisition unit 21, determination unit 22, and motor control unit 23 of the control unit 2 can be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

The storage unit 3 corresponds to a RAM or a flash memory. The RAM or the flash memory can store map information 31, information on various programs, and the like. The motor control device 1 may also acquire the above-mentioned programs and various information via other computers or portable recording media connected via a wired or wireless network.

Map information 31 is threshold information used in the judgment process by judgment unit 22 described below. FIG. 3 is information showing an example of map information 31. Map information 31 shown in FIG. 3 is generated in advance based on experimental results, etc. As shown in FIG. 3, map information 31 is information that links threshold information (first threshold TH1, second threshold TH2) to rotational acceleration and torque of vehicle C. Specifically, first threshold TH1 is a threshold that distinguishes between a spin state and a slip state, and second threshold TH2 is a threshold that distinguishes between a slip state and a normal state.

Next, we will explain each function of the control unit 20 (acquisition unit 21, determination unit 22, and motor control unit 23).

The acquisition unit 21 acquires various information. For example, the acquisition unit 21 acquires information on the rotation speed of the motor M from the rotation speed sensor 100. The acquisition unit 21 also calculates the rotation acceleration based on the change over time in the rotation speed of the motor M.

The determination unit 22 performs various determination processes. For example, the determination unit 22 determines whether the motor M is in a free-spinning state or a slipping state based on the rotational acceleration of the motor M. Specifically, the determination unit 22 refers to the map information 31, and determines that the motor M is in a free-spinning state when the rotational acceleration is equal to or greater than a first threshold value, and determines that the motor M is in a slipping state when the rotational acceleration is less than the first threshold value and equal to or greater than a second threshold value that is lower than the first threshold value.

The motor control unit 23 performs recovery control for the motor M that has been determined by the determination unit 22 to be in an abnormal rotation speed state (idling or slipping), to recover from the abnormal rotation speed state. Specifically, the motor control unit 23 differentiates the content of the recovery control depending on whether the motor M is determined to be in an idling state or a slipping state.

First, the return control when it is determined that the wheel is in a spinning state will be described. When it is determined that the wheel is in a spinning state, the motor control unit 23 issues a torque command to the motor M so that the rotation of the wheel stops. Specifically, the motor control unit 23 sets the target rotation speed of the wheel to zero, and controls the torque command value to a negative value so that the actual rotation speed converges to the target rotation speed through feedback control. This allows the wheel in a spinning state to be stopped, so that the wheel can be returned from the spinning state with high accuracy.

Next, the return control when a slip state is determined will be described. When a slip state is determined, the motor control unit 23 issues a torque command to the motor M so that the rotation speed of the wheel becomes the rotation speed before the slip state was determined. Specifically, the motor control unit 23 sets the target rotation speed of the wheel to the rotation speed of the wheel before the slip state was determined, and controls the torque command value to a negative value so that the actual rotation speed converges to the target rotation speed through feedback control. This makes it possible to return to the rotation speed before the slip, and therefore to return from the slip state with high accuracy.

Here, the return control during a slip state will be explained using FIG. 4. FIG. 4 is an explanatory diagram of the return control during a slip state. In the example shown in FIG. 4, it is assumed that the determination unit 22 determines that a slip state has occurred at time t2.

In such a case, the motor control unit 23 sets the target rotation speed of the wheel to, for example, the rotation speed at time t1. In other words, the motor control unit 23 sets the target rotation speed to the rotation speed when the wheel was in a normal rotation state 100 ms (an example of a predetermined time) before the slip started.

Then, the motor control unit 23 sets the torque command value to a negative value after time t2 so that the actual rotation speed converges to the target rotation speed. Note that in FIG. 4, the rotation speed 100 ms before the slip state is determined is set as the target rotation speed, but it is not limited to 100 ms and any predetermined time can be set according to the type of vehicle C and the wheel condition (tire deterioration over time, type, etc.).

In this way, the motor control unit 23 can recover from a slip state with high accuracy by setting the rotation speed a predetermined time before the slip state occurs as the target rotation speed.

Next, the torque redistribution process in a spinning state and a slipping state will be described with reference to Figures 5 and 6. Figure 5 is a diagram showing the torque redistribution process in a spinning state. Figure 6 is a diagram showing the torque redistribution process in a slipping state. Note that Figures 5 and 6 explain the case where the right front wheel is in a spinning state and a slipping state. In other words, the three wheels other than the right front wheel are in a non-spinning state and a non-slip state.

As shown in FIG. 5, when the motor control unit 23 determines that the wheels are in a spinning state, it redistributes the torque distributed to the motor M of the wheels that are in a spinning state to the motor M of the wheels that are not in a spinning state. In the example shown in FIG. 5, the motor control unit 23 satisfies the torque required by the vehicle by redistributing the torque distributed to the motor M of the right front wheel to the motors M of the other three wheels.

The motor control unit 23 may redistribute the torque evenly to each of the three motors M, or may redistribute the torque so that the torque ratio of the three motors M does not change. Alternatively, the motor control unit 23 may redistribute the torque so that the straight-line running ability of the vehicle C does not decrease when the vehicle C is traveling straight, and may redistribute the torque so that the turning ability does not decrease when the vehicle C is turning.

In this way, the torque of the motor M in a spinning state is redistributed to the motor M in a non-spinning state to satisfy the required torque, thereby eliminating the spinning state and ensuring off-road performance.

Next, as shown in FIG. 6, when it is determined that a slip state is occurring, the motor control unit 23 prohibits the redistribution of the torque distributed to the motor M in the slip state to the motor M in the non-slip state.

This is because there is a high possibility that the slip state is caused by the road surface condition, and if torque were to be redistributed to a motor M that is not in a slip state, there is a high possibility that the non-slip state would change into a slip state.

In this way, by prohibiting torque redistribution from the motor M in a slipping state, it is possible to prevent a wheel that is not in a slipping state from going into a slipping state.

In addition, when the motor control unit 23 is performing return control, it performs a return completion determination. Specifically, in the case of a slip state, the motor control unit 23 determines that the motor has returned from the slip state when the actual rotation speed converges to the target rotation speed (when the difference between the actual rotation speed and the target rotation speed is less than a predetermined value).

When the motor control unit 23 determines that the vehicle has recovered from the slip state, it returns the torque command value to zero and then gradually returns the torque distribution to normal, thereby terminating the recovery control.

In addition, in the case of a spinning state, the motor control unit 23 first returns the torque command value to zero when the actual rotation speed converges to the target rotation speed. Then, after returning the torque command value to zero, the motor control unit 23 determines that the wheel has returned from the spinning state when the wheel has reached a predetermined rotation speed or higher. In other words, when the wheel is rotating without outputting torque, the motor control unit 23 determines that the wheel is gripping the road surface and rotating, and determines that the wheel has returned from the spinning state.

When the motor control unit 23 determines that the vehicle has recovered from the free-spinning state, it gradually returns the torque distribution to normal and ends the recovery control. This allows the vehicle to recover from the free-spinning state and slipping state with high accuracy.

Note that, if the actual rotation speed transitions away from the target rotation speed (the rotation speed increases) during convergence determination to the target rotation speed, the motor control unit 23 determines that the wheels are gripping and have returned from a spinning or slipping state.

Next, the processing procedure of the processing executed by the motor control device 1 according to the embodiment will be described with reference to Figs. 7 to 9. Figs. 7 to 9 are flowcharts showing the processing procedure of the processing executed by the motor control device 1 according to the embodiment. Note that the processing sequence shown in Figs. 7 to 9 is first performed in the order of Fig. 7 → Fig. 8 (or Fig. 8 → Fig. 7) → Fig. 9.

First, the process from the process of determining whether the rotation speed is abnormal to the process of restoring control will be described with reference to FIG. 7. Note that the process shown in FIG. 7 is performed for each wheel.

As shown in FIG. 7, the control unit 2 of the motor control device 1 calculates the rotational acceleration of the motor M (step S101). Next, the control unit 2 determines the first threshold value TH1 and the second threshold value TH2 to be used in the judgment process from the current torque (step S102).

Next, the control unit 2 uses the first threshold value TH1 and the second threshold value TH2 to determine whether or not the vehicle is in a free-spinning state (step S103). If the vehicle is in a free-spinning state (step S103: Yes), the control unit 2 sets the target rotation speed to zero (step S104), calculates a torque command value from the actual rotation speed and the target rotation speed (step S105), and ends the process.

On the other hand, in step S103, if the vehicle is not in an idling state (step S103: No), the control unit 2 determines whether the vehicle is in a slipping state (step S106). If the vehicle is in a slipping state (step S106: Yes), the control unit 2 sets the target rotation speed to the rotation speed a predetermined time ago (step S107) and executes step S105.

Also, if the slip state is not present (step S106: No), the control unit 2 ends the process.

Next, the process of determining whether or not the rotation speed has returned from an abnormal state will be described with reference to FIG. 8. Note that the process shown in FIG. 8 is performed for each wheel (or for all wheels that are spinning/slipping).

As shown in FIG. 8, the control unit 2 first determines whether or not the idle-spin state is being determined (step S201). If the idle-spin state is being determined (step S201: Yes), the control unit 2 determines whether or not the actual rotation speed has converged to the target rotation speed (zero rotation speed) (step S202).

When the actual rotation speed converges to the target rotation speed (step S202: Yes), the control unit 2 sets the torque to zero (step S203) and determines whether the wheels have gripped the road surface (whether the wheels are rotating with the torque at zero) (step S204). If the wheels have gripped the road surface (step S204: Yes), the control unit 2 determines that the wheels have returned from a spinning state (step S205) and ends the process. When the wheels have returned from a spinning state, the torque is gradually restored (returned to normal torque distribution).

On the other hand, in step S201, if the control unit 2 is not determining whether the vehicle is in a spin state (step S201: No), the control unit 2 determines whether the vehicle is in a slip state (step S206).

If the control unit 2 is determining whether the slip state is being determined (step S206: Yes), it determines whether the actual rotation speed has converged to the target rotation speed (the rotation speed a predetermined time ago) (step S207). On the other hand, if the control unit 2 is not determining whether the slip state is being determined (step S206: No), it ends the process.

In addition, in step S207, if the actual rotation speed has converged to the target rotation speed (step S207: Yes), the control unit 2 executes step S205. When recovering from a slip state, the torque is gradually restored from zero. On the other hand, in step S207, if the actual rotation speed has not converged to the target rotation speed (step S207: No), the control unit 2 determines that the abnormal rotation speed state continues (step S208) and ends the process.

Next, the torque redistribution process when the rotation speed is abnormal will be explained using FIG. 9. Note that the process shown in FIG. 9 is performed only once for each wheel.

As shown in FIG. 9, the control unit 2 first determines whether or not there is a motor M in a slipping state (step S301). If there is a motor M in a slipping state (step S301: Yes), the control unit 2 prohibits the reallocation of the torque distribution of the slipping motor M to other motors M (step S302). Next, the control unit 2 causes the motor M in a normal state (non-slip and non-spinning state) to output a quarter of the required torque (the torque for one wheel, here the torque when the required torque is evenly distributed to the wheels) (step S303), and ends the process.

On the other hand, in step S301, if there is no motor M in a slipping state (step S301: No), the control unit 2 determines whether there is a motor M in an idling state (step S304).

If there is a motor M in a spinning state (step S304: Yes), the control unit 2 determines whether there is a motor M in a non-spinning state (step S305). If there is a motor M in a non-spinning state (step S305: Yes), the control unit 2 reallocates the torque of the motor M in a spinning state to the motor M in a non-spinning state (step S306). If there is no motor M in a non-spinning state (step S305: No), the control unit 2 ends the process. Next, the control unit 2 causes each motor M in a non-spinning state to output the reallocated torque (step S307), and ends the process.

On the other hand, in step S304, if there is no motor M in an idling state (step S304: No), the control unit 2 causes all motors M in a normal state to output a quarter of the required torque (the torque when the required torque is evenly distributed to the wheels) (step S308), and ends the process.

Note that the above-mentioned map information 31 is information that has been generated and stored in advance, and therefore assumes that the wheels, etc. of vehicle C are in the same condition as when the vehicle was shipped. For this reason, if the wheels, etc., and other related parts have deteriorated over time, or if the user has replaced the tires or wheels after purchasing the vehicle, the pre-stored map information 31 may not be able to accurately determine spinning or slipping. For example, if the user replaces the tires or wheels after purchasing the vehicle, the weight and weight balance of the wheels may change from the standard equipment, and the rotational acceleration conditions for spinning or slipping may be different for the changed wheels compared to the standard equipment wheels.

Therefore, by using map information 31 generated based on the state of the vehicle at the time of shipment, there is a risk of erroneously determining that the vehicle is in a spinning state when in fact the vehicle is in a slipping state.

Therefore, based on the determination result of the abnormal rotation speed state, the determination unit 22 corrects the threshold value (particularly the first threshold value TH1) of the map information 31. Specifically, when any of the following four determination results is obtained, the determination unit 22 corrects the map information 31, since there is a high possibility that the determination is erroneous due to an error in the map information 31.
(1) Three or more of the four wheels are judged to be in a spinning state. (2) During the return control in the case of a spinning state, the wheel grip frequently causes the spinning state to be resolved. (3) The other wheels go into a spinning state due to the torque redistribution during the spinning state. (4) The other wheels go into a slipping state due to the torque redistribution during the spinning state.

(1) Three or more of four wheels are judged to be spinning The spinning state occurs when some of the wheels are not in contact with the ground due to unevenness of the road surface, so it is possible that up to two wheels may spin at the same time, but it is considered that the possibility of three or more wheels spinning at the same time is extremely low in reality. In other words, if three or more wheels are judged to be spinning at the same time, there is a high possibility that this is an erroneous judgment due to an error in the map information 31.

(2) During recovery control in the event of a spin, spin is frequently eliminated due to wheel grip. As described above, during recovery control in the event of a spin, the target rotation speed is set to zero. However, the more frequently the actual rotation speed does not converge to zero but instead rises, resulting in a determination that grip has been achieved and recovery being made, the more likely it is that a misjudgment will occur.

(3) Torque redistribution during slippage causes other wheels to slip. The torque of the slipping motor M is redistributed to the non-spinning motor M, but it is considered highly unlikely that the non-spinning motor M will slip due to an increase in torque. In other words, there is a high possibility that the wheel is erroneously judged to be in a slippage state even though a slippage state actually occurs.

(4) Other wheels slip due to torque redistribution during spinning The torque of the spinning motor M is redistributed to the non-spinning motor M, but the possibility that the non-spinning motor M will slip due to an increase in torque is higher than in (3). However, it is extremely rare for the wheels to spin due to unevenness of the road surface when traveling at a relatively high speed on a slippery road surface. In other words, there is a high possibility that the wheels are erroneously determined to be in a spinning state even when a slipping state actually occurs (however, this is lower than in (3)).

When the determination unit 22 obtains the above determination results (1) to (4), it corrects the first threshold value TH1 of the map information 31 as shown in FIG. 10. FIG. 10 is a diagram showing the correction process of the map information 31.

As shown in FIG. 10, the determination unit 22 first calculates the deviation between the maximum value of the rotational acceleration when it is determined that the vehicle is in a spinning state and the first threshold value TH1, and calculates the correction amount by multiplying this deviation by a predetermined correction coefficient. The determination unit 22 then corrects the first threshold value TH1 based on this correction amount (dotted line in FIG. 10).

In this way, the judgment unit 22 can improve the accuracy of the judgment result in the subsequent judgment process by correcting the map information 31 from the actual judgment result.

The correction coefficient can be set to any value, but for example, the higher the possibility of erroneous judgment, the higher the value. As an example, in the order of (1) to (4), the correction coefficient for (1) is set to the highest and the correction coefficient for (4) is set to the lowest. For (2), the higher the frequency, the higher the correction coefficient.

As described above, the motor control device 1 includes a determination unit 22 and a motor control unit 23. In a vehicle C in which a plurality of wheels are driven by different motors M, the determination unit 22 determines whether each motor M is in an abnormal rotation speed state based on the rotation acceleration of the motor M. The motor control unit 23 performs return control to return the motor M determined by the determination unit 22 to an abnormal rotation speed state from the abnormal rotation speed state. The determination unit 22 determines that the motor M is in a free-spin state when the rotation acceleration is equal to or greater than a first threshold value, and determines that the motor M is in a slip state when the rotation acceleration is less than the first threshold value and equal to or greater than a second threshold value lower than the first threshold value. The motor control unit 23 performs different return control depending on whether the motor M is in a free-spin state or a slip state. This allows optimal return control to be performed according to the content of the abnormal rotation speed state, thereby allowing the motor M to be appropriately returned to an abnormal rotation speed state.

In the above embodiment, a four-wheeled vehicle C is used as an example, but the present invention can be applied to any vehicle with two or more wheels. In addition, the basic slip/spin determination process and return control can be applied to a one-wheeled vehicle.

In addition, while vehicle C has been shown to have two front wheels and two rear wheels, it may have three or more wheels in the width direction of the vehicle, or three or more wheels in the length direction of the vehicle, making it a vehicle with five or more wheels.

In the above embodiment, all four wheels are driven, but some of the wheels (for example, the two front wheels out of the four wheels) may be driven. In addition, the motor M is not limited to an in-wheel motor, and any configuration can be used as long as it is capable of individually controlling the torque of each wheel (drive wheel).

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

Reference Signs List 1 Motor control device 2 Control unit 3 Storage unit 20 Control unit 21 Acquisition unit 22 Determination unit 23 Motor control unit 31 Map information 100 Rotational speed sensor C Vehicle M Motor TH1 First threshold TH2 Second threshold

Claims (4)

A motor control device for controlling a plurality of motors in a vehicle in which each of the wheels is driven by a separate motor, comprising:
a control unit that determines that the motor is in an idling state when a rotation acceleration of the motor is equal to or greater than a first threshold, and that the motor is in a slip state when the rotation acceleration is less than the first threshold and equal to or greater than a second threshold that is lower than the first threshold,
The control unit is
When the wheel is determined to be in the spin state, if the wheel is detected to have stopped rotating by issuing a torque command to stop the rotation of the wheel, a return control is performed to determine that the wheel has returned from the spin state when the wheel rotation is detected in a state where no torque is being output, and when the wheel is determined to be in the slip state , a return control different from that performed when the wheel is determined to be in the spin state is performed.
Motor control device. The control unit is
When it is determined that the motor is in the free-spinning state, the torque distributed to the motor in the free-spinning state is redistributed to the motor in the non-free-spinning state, and when it is determined that the motor is in the slipping state, the torque distributed to the motor in the slipping state is not redistributed to the motor in the non-slip state.
The motor control device according to claim 1 . The control unit is
When it is determined that the wheel is in a slip state, a torque command is issued to the motor so that the number of revolutions of the wheel becomes the number of revolutions before the wheel is determined to be in a slip state.
The motor control device according to claim 1 . A motor control method for a vehicle in which a plurality of wheels are driven by separate motors, the method comprising:
When the rotation acceleration of the motor is equal to or greater than a first threshold, it is determined that the motor is in an idling state, and when the rotation acceleration is less than the first threshold and equal to or greater than a second threshold that is lower than the first threshold, it is determined that the motor is in a slip state;
When the wheel is determined to be in the spin state, if the wheel is detected to have stopped rotating by issuing a torque command to stop the rotation of the wheel, a return control is performed to determine that the wheel has returned from the spin state when the wheel rotation is detected in a state where no torque is being output, and when the wheel is determined to be in the slip state , a return control different from that performed when the wheel is determined to be in the spin state is performed.
Motor control methods.

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