JP7313973B2 - MOTOR CONTROL DEVICE AND MOTOR CONTROL METHOD - Google Patents

Description

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

2. Description of the Related Art Conventionally, various motor control devices have been proposed that control rotational drive motors attached to left and right drive wheels of a vehicle (see, for example, Patent Document 1). It should be noted that, in the conventional technology described above, the vehicle is turned by controlling the motors individually.

JP 2007-106171 A

However, the prior art still has room for further improvement in terms of improving the turning performance of the vehicle.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor control device and a motor control method capable of improving the turning performance of a vehicle.

In order to solve the above problems and achieve the object, the present invention provides a motor control device including a motor control section. The motor control unit individually controls the rotational drive motors attached to the left and right drive wheels of the vehicle. Further, when the vehicle turns, the motor control unit executes a first turning control in which the motor for the inner wheel is controlled to apply a first negative torque to the inner wheel of the left and right driving wheels that is located inside when the vehicle turns, and after applying the first negative torque to the inner wheel, the motor is controlled to apply a second negative torque smaller than the first negative torque to the inner wheel.

ADVANTAGE OF THE INVENTION According to this invention, the turning performance of a vehicle can be improved.

FIG. 1A is a diagram showing an overview of a motor control method according to an embodiment. FIG. 1B is a diagram showing an outline of a motor control method according to the embodiment; FIG. 2 is a block diagram showing the configuration of the motor control device according to the embodiment. FIG. 3A is a diagram showing the vehicle before executing the first turning control. FIG. 3B is a diagram showing the vehicle after execution of the first turning control. FIG. 4 is a flow chart showing an example of a processing procedure executed by the motor control device.

Hereinafter, embodiments of a motor control device and a motor control method disclosed in the present application will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

First, an overview of the motor control method according to the embodiment will be described below with reference to FIGS. 1A and 1B. 1A and 1B are diagrams schematically showing an outline of a motor control method according to an embodiment.

As shown in FIG. 1A, the vehicle C is, for example, a four-wheeled vehicle with four drive wheels 50. As shown in FIG. Hereinafter, the left front driving wheel 50 of the vehicle C may be referred to as "left front wheel 50FL", the right front driving wheel 50 as "right front wheel 50FR", the left rear driving wheel 50 as "left rear wheel 50RL", and the right rear driving wheel 50 as "right rear wheel 50RR". Note that the number of drive wheels 50 is not limited to the example in FIG. 1A. That is, the number of driving wheels 50 may be three or less, or five or more, as long as they are present on the left and right sides of the vehicle C, respectively. Moreover, all the wheels provided in the vehicle C do not have to be driving wheels, and for example, the driving wheels may be only the front wheels or only the rear wheels.

The vehicle C is equipped with a motor control device 10 and a motor 60 . The motors 60 are attached to the drive wheels 50 and drive the drive wheels 50 to rotate. That is, there are a plurality of motors 60, and each drive wheel 50 of the vehicle C is rotationally driven. Hereinafter, the motor 60 attached to the left front wheel 50FL may be referred to as "left front wheel motor 60FL", the motor 60 attached to the right front wheel 50FR as "right front wheel motor 60FR", the motor 60 attached to the left rear wheel 50RL as "left rear wheel motor 60RL", and the motor 60 attached to the right rear wheel 50RR as "right rear wheel motor 60RR".

The motor controller 10 can control the motors 60 individually. For example, the motor control device 10 can control each motor 60 by outputting a command value to the motor 60 according to the operation amount of an accelerator pedal (not shown). By such control of the motor 60, the motor 60 is rotationally driven, and the drive wheels 50 are rotated with the rotation of the motor 60, so that the vehicle travels.

In the motor control device 10 according to this embodiment, the turning performance of the vehicle C is improved by appropriately controlling the motor 60 described above.

Specifically, when a steering wheel 51 is operated by a driver (not shown) to request the vehicle C to turn, for example, the front left wheel 50FL and the front right wheel 50FR are steered in the turning direction. In the example of FIG. 1A, the front left wheel 50FL and the front right wheel 50FR are steered toward the right side of the vehicle C, and the vehicle C makes a right turn as indicated by arrow A. In FIG. Here, it is assumed that the vehicle C turns while traveling at a low speed.

The motor control device 10 according to the present embodiment determines whether or not the driver desires (desires) a rapid turn. For example, when the vehicle speed is less than a predetermined speed and the steering operation amount of the steering wheel 51 is operated to a predetermined maximum amount or near a predetermined maximum amount, the motor control device 10 determines that the driver desires a rapid turn for a U-turn, for example.

It should be noted that the above-described conditions for determining that the driver desires a rapid turn are merely examples and are not limited. That is, for example, in addition to the above conditions, a navigation device, a camera, or the like may be used to determine whether or not a sharp turn such as a U-turn is possible around the vehicle, or other conditions.

Then, as shown in FIG. 1B, when it is determined that the driver desires a sharp turn and the vehicle C turns, the motor control device 10 controls the inner wheel motor (the right rear wheel motor 60RR in the example of FIG. 1B) so as to apply a first negative torque D1 to the inner wheel (right rear wheel 50RR in the example of FIG. 1B) of the left and right drive wheels 50 that is located inside when the vehicle turns.

Here, the first negative torque D1 is torque in the direction of stopping the inner wheel (right rear wheel 50RR), specifically, negative torque that causes the inner wheel to slip.

As a result, the inner wheels that have been rotating due to the low-speed running of the vehicle C enter a slip state (including a substantially slip state). When the inner ring slips, the wheel is separated from the road surface, so the applied negative torque rapidly reduces the rotational speed of the inner ring regardless of the running speed of the vehicle C. After that, when the number of revolutions of the inner ring drops to a certain number of revolutions (for example, a number of revolutions close to zero), the inner ring shifts from the slip state to the grip state, but since it grips the road surface when the number of revolutions is low, the inner ring stops rotating (including a state where it almost stops). Therefore, the vehicle C can turn with the inner wheel that has stopped rotating as the fulcrum B, and the turning radius of the vehicle C can be reduced, so that the turning performance of the vehicle C can be improved.

Here, the motor control device 10 can control the motor 60 so that the drive torque (total drive torque) of the entire vehicle C is not reduced by applying the first negative torque D1 to the inner wheels.

Specifically, when applying a negative torque (for example, a first negative torque D1) to the inner wheels, the motor control device 10 controls the outer wheel motor 60 (the left rear wheel motor 60RL in the example of FIG. 1B) so that the positive torque E1 is applied to the outer wheel (the left rear wheel 50RL in the example of FIG. 1B) of the left and right drive wheels 50 that is on the outside when the vehicle turns. Note that the positive torque E1 is set to a required torque amount required for the vehicle C, for example. Alternatively, the positive torque E1 may be a value obtained by adding the same amount of torque as the absolute value of the negative torque applied to the inner ring to the amount of torque applied so far as positive torque to the outer ring.

As a result, it is possible to suppress a decrease in the driving torque (total driving torque) of the vehicle C as a whole, and for example, it is possible to make it difficult for the driver to feel uncomfortable. In addition, since the driving torque on the outer wheel side is larger than that on the inner wheel, it is possible to increase the amount of turning.

In addition, the motor control device 10 can control the motor 60 to grip the road surface (in other words, to maintain the grip state) of the inner ring whose rotation has stopped or has almost stopped by applying the second negative torque D2.

Specifically, the motor control device 10 applies a first negative torque D1 to the inner wheel (right rear wheel 50RR), and then controls the motor 60 (right rear wheel motor 60RR) to apply a second negative torque D2 smaller than the first negative torque D1 to the inner wheel.

As a result, it is possible to prevent the inner ring from further rotating in the reverse direction from the state of gripping the road surface and stopping, thereby maintaining the stopped state. That is, the state in which the inner ring functions as the fulcrum B can be maintained.

Hereinafter, when the vehicle C turns, the turning control that controls the motor 60 so as to apply the first negative torque D1 to the inner wheels, apply the first negative torque D1, and then apply the second negative torque D2 to the inner wheels may be referred to as "first turning control".

Further, as described above, the motor control device 10 controls the inner wheel motor 60 to apply the first negative torque D1 to the inner wheels when the vehicle C is traveling at a low speed, more specifically, when the speed of the vehicle C is less than the predetermined speed, in other words, it executes the first turning control. Conversely, the motor control device 10 prohibits execution of the first turning control when the speed of the vehicle C is equal to or higher than the predetermined speed. The predetermined speed is a relatively small value that allows it to be determined that the vehicle C is traveling at a low speed, and is an example of a first speed.

As a result, for example, when the vehicle is traveling at a low speed, the turning control according to the present embodiment is performed, so that it is possible to reliably prevent the occurrence of a vehicle spin or the like that may occur if a sharp turn is performed while the vehicle is traveling at a high speed.

Next, the configuration of the motor control device 10 according to the embodiment will be described in detail with reference to FIG. FIG. 2 is a block diagram showing the configuration of the motor control device 10 according to the embodiment. In addition, in FIG. 2, only the components necessary for explaining the features of the present embodiment are represented by functional blocks, and the description of general components is omitted.

In other words, each component illustrated in FIG. 2 is functionally conceptual and does not necessarily need to be physically configured as illustrated. For example, the specific form of distribution/integration of each functional block is not limited to the illustrated one, and all or part of them can be functionally or physically distributed/integrated in arbitrary units according to various loads and usage conditions.

As shown in FIG. 2 , the motor control device 10 is connected with a rotation speed sensor 40 , a steering angle sensor 41 , a vehicle speed sensor 42 , a yaw rate sensor 43 and each motor 60 .

The rotation speed sensor 40 is a sensor that detects the rotation speed of the four motors 60 . The steering angle sensor 41 is a sensor that detects the steering operation amount of the steering wheel 51 (see FIG. 1A). The vehicle speed sensor 42 is a sensor that detects the speed of the vehicle C. As shown in FIG. The yaw rate sensor 43 is a sensor that detects the turning speed of the vehicle C. As shown in FIG. These rotational speed sensor 40 , steering angle sensor 41 , vehicle speed sensor 42 and yaw rate sensor 43 output signals indicating detection results to motor control device 10 .

The motor 60 is connected to the drive wheel 50 (see FIG. 1A) and drives the drive wheel 50 to rotate. An in-wheel motor can be used as the motor 60 . Also, the motor 60 is controlled based on a command value input from the motor control device 10 .

The motor control device 10 includes a control section 20 and a storage section 30 . The control unit 20 includes a detection unit 21 , a turning determination unit 22 , a motor control unit 23 and a notification unit 24 .

The control unit 20 includes, for example, a computer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input/output port, and various circuits.

The CPU of the computer functions as the detection unit 21, the turning determination unit 22, the motor control unit 23, and the notification unit 24 of the control unit 20 by reading and executing programs stored in the ROM, for example.

Further, at least some or all of the detection unit 21, the turning determination unit 22, the motor control unit 23, and the notification unit 24 of the control unit 20 can be configured by hardware such as ASIC (Application Specific Integrated Circuit) and FPGA (Field Programmable Gate Array).

The storage unit 30 is, for example, a rewritable non-volatile memory such as a data flash or HDD (Hard Disk Drive), or a storage device such as a register, and stores various programs and information.

A detection unit 21 of the control unit 20 detects the rotation speed of the driving wheels 50 based on the signal output from the rotation speed sensor 40 . Further, the detection unit 21 detects the steering operation amount of the steering wheel 51 based on the signal output from the steering angle sensor 41 . Also, the detection unit 21 detects the vehicle speed based on the signal output from the vehicle speed sensor 42 . Also, the detection unit 21 detects the yaw rate based on the signal output from the yaw rate sensor 43 .

The detection unit 21 notifies the motor control unit 23 of the detected number of revolutions of the driving wheels 50, the vehicle speed, the yaw rate, and the like. Further, the detection unit 21 notifies the turning determination unit 22 of the detected amount of steering operation and the like.

The turning determination unit 22 determines whether or not the driver desires a rapid turn. Such a turn may be a state in which the vehicle C is actually turning, a state before the vehicle C starts turning, in other words, a state in which the vehicle C is about to start turning.

For example, the turning determination unit 22 determines that the driver desires a rapid turn based on the vehicle speed and steering operation amount. Specifically, for example, the turning determination unit 22 determines that the driver desires a rapid turn when the vehicle speed is less than a predetermined speed and the steering operation amount is equal to or greater than a predetermined operation amount (more specifically, a predetermined maximum amount). Note that the turning determination unit 22 notifies the motor control unit 23 of the determination result.

The motor controller 23 individually controls the motors 60 . For example, when it is determined that the driver desires rapid turning and the vehicle C turns, the motor control unit 23 executes the first turning control. As described above, the motor control unit 23 can steer the front left wheel 50FL and the front right wheel 50FR (see FIG. 1A) in the turning direction, and turn the vehicle C in the steered state.

Specifically, when the vehicle C turns, the motor control unit 23 controls the motor 60 for the inner wheels so as to apply a first negative torque D1 to the inner wheels of the left and right drive wheels 50 that are positioned inside when the vehicle turns. Note that the first negative torque D1 is calculated by the following formula (1).
First negative torque = load on inner ring x dynamic friction coefficient of road surface + moment of inertia of tire
... formula (1)

As a result, the inner wheels enter a slip state and then shift to a grip state and stop rotating, so that the vehicle C can turn with the inner wheels as the fulcrum B (see FIG. 1B). Therefore, in this embodiment, the turning radius of the vehicle C can be reduced, and the turning performance of the vehicle C can be improved.

Further, the motor control unit 23 controls the motor 60 so as to apply the first negative torque D1 to the inner ring at once within a relatively short predetermined time range. That is, if the first negative torque D1 is applied over a long time exceeding the predetermined time range, the vehicle C is decelerated, but by applying the first negative torque D1 within the predetermined time range, the inner wheels can be brought into a slip state immediately.

Further, the motor control unit 23 can control the motor 60 to apply the second negative torque D2 (see FIG. 1B) to the inner ring after applying the first negative torque D1 to the inner ring. The second negative torque D2 is smaller than the first negative torque D1 and is set to a value that allows the inner ring to keep gripping the road surface. Specifically, since the inner wheels are subjected to a pulling force from the turning vehicle C or the like due to the driving of the drive wheels 50 other than the inner wheels, the second negative torque D2 is set to a value capable of resisting such force. For example, the second negative torque D2 is set based on the moment of inertia of the vehicle C or the like.

By applying the second negative torque D2 in this manner, the inner ring can continue to grip the road surface, that is, to maintain a stopped state. Therefore, the state in which the inner ring functions as the fulcrum B can be maintained, so that the vehicle C can be turned more reliably with the inner ring serving as the fulcrum B, and as a result, the turning performance of the vehicle C can be further improved.

The application of the first negative torque D1 may be switched to the application of the second negative torque D2, for example, at the timing when it is determined (estimated) that a slip state has occurred in the inner ring.

For example, after applying the first negative torque D1 to the inner wheel, the motor control unit 23 can determine whether or not the inner wheel is slipping based on the detected rotational speed of the driving wheel 50. Specifically, the motor control unit 23 calculates the rotation speed acceleration based on the detected rotation speed of the drive wheel 50, and when the rotation speed acceleration becomes equal to or less than a predetermined rotation speed acceleration indicating the occurrence of a slip state (a state in which the rotation speed deceleration is large), it can be determined that the slip state has occurred in the inner ring.

Then, when the motor control unit 23 determines that the slip state has occurred in the inner ring, the application of the first negative torque D1 is switched to the application of the second negative torque D2. Thereby, the motor control unit 23 can switch from application of the first negative torque D1 to application of the second negative torque D2 at an appropriate timing when a slip state occurs in the inner ring. Note that the switching timing described above is merely an example and is not limited.

In addition, when applying negative torque to the inner wheels, the motor control unit 23 can control the motor 60 for the outer wheels so that positive torque E1 (see FIG. B) is applied to the outer wheels that are on the outside when the vehicle turns. For example, the positive torque E1 is set according to the amount of torque required for the vehicle C. Note that the required torque amount is set according to the operation amount of an accelerator pedal (not shown) or the like.

Specifically, the motor control unit 23 controls the outer ring motor 60 so as to increase the positive torque E1 applied to the outer ring. Specifically, the motor control unit 23 controls the outer wheel motor 60 so that the total amount of torque applied to all the drive wheels 50 becomes the requested torque amount required for the vehicle C. As shown in FIG.

More specifically, the motor control unit 23 applies to the outer ring a positive torque E1 obtained by adding a torque amount equal to the absolute value of the negative torque applied to the inner ring to the torque amount applied so far as a positive torque to the outer ring. As a result, it is possible to suppress a decrease in driving torque of the vehicle C as a whole when a negative torque (for example, the first negative torque D1) is applied to the inner wheels.

Further, when the speed of the vehicle C is less than a predetermined speed (first speed) and the vehicle C is traveling at a low speed, the motor control unit 23 executes the first turning control, more specifically, controls the motor 60 for the inner wheels so as to apply a first negative torque to the inner wheels. As a result, for example, the first turning control is performed when the vehicle is traveling at low speed, so that it is possible to reliably prevent the occurrence of a vehicle spin or the like that may occur if a sharp turn is performed while traveling at high speed.

Turning of the vehicle C before and after execution of the above-described first turning control will now be described in detail with reference to FIGS. 3A and 3B. FIG. 3A is a diagram showing the vehicle C before execution of the first turning control, and FIG. 3B is a diagram showing the vehicle C after execution.

In FIGS. 3A and 3B, the vectors of the front wheels such as the front left wheel 50FL and the front right wheel 50FR are indicated by "vector Hf", and the vectors of the rear wheels such as the rear left wheel 50RL and the rear right wheel 50RR are indicated by "vector Hrx, Hr". "Vector Hcx, Hc" indicates the moving direction vector of the vehicle C obtained by synthesizing the vector of the front wheels and the vector of the rear wheels. In addition, in FIGS. 3A and 3B, the vectors that change due to the execution of the first turning control are shown with an "x" attached to the end of the code of the vector before execution. In addition, in FIG. 3B, the moving direction vector Hcx before execution is indicated by a dashed line for easy understanding by comparison.

As described above, when the first turning control (motor control) that applies the first negative torque D1 to the inner wheel (the right rear wheel 50RR in the example of FIG. 3B) is executed, the inner wheel enters a slip state and then a grip state, so that rotation is stopped. Since the coefficient of friction of the inner ring changes from the coefficient of dynamic friction to the coefficient of static friction, the frictional force acting on the inner ring increases. As a result, the vehicle C turns with the inner wheel (right rear wheel 50RR) as the fulcrum B, and as shown in FIG. 3B, the rear wheel vector Hr shifts to the inside of the turn. Along with the transition of the vector Hr of the rear wheels, the vector Hc of the moving direction after the execution of the first turning control also transitions to the inner side of the turn, and the turning performance of the vehicle C is improved.

Returning to the description of FIG. 2, for example, when the vehicle C turns when the vehicle C is not traveling at a low speed or stopped, the motor control unit 23 may perform motor control that applies the above-described first negative torque to the inner wheels, that is, motor control different from the first turning control.

For example, the motor control unit 23 may prohibit the execution of the first turning control when the speed of the vehicle C is equal to or higher than a predetermined speed (first speed).

As a result, the turning of the vehicle C can be stabilized. That is, if the first negative torque is applied to the inner wheels when the speed of the vehicle C is equal to or higher than the predetermined speed and the vehicle C is not traveling at a low speed, the behavior of the vehicle C during turning tends to become unstable. Therefore, as described above, the turning of the vehicle C can be stabilized by prohibiting the motor control (first turning control) for applying the first negative torque. Note that the motor control unit 23 may prohibit the first turning control for applying the first negative torque to the inner wheels also when the steering operation amount is less than the predetermined maximum amount.

Further, when the speed of the vehicle is equal to or higher than a predetermined speed and the first turning control is prohibited and is not performed, the motor control unit 23 may execute normal motor control, or may execute motor control during turning, which is different from the first turning control. Hereinafter, such motor control during turning may be referred to as "second turning control".

As the second turning control, the motor control unit 23 controls the motor 60 so as to apply, for example, negative torque to the inner wheel within a range in which a slip state does not occur. As a result, the motor control unit 23 can prevent the inner wheels of the vehicle C from slipping during turning and the behavior of the vehicle from becoming unstable.

Note that the motor control unit 23 may apply, to the outer wheel, positive torque corresponding to the negative torque applied to the inner wheel when executing the second turning control.

Next, turning when the vehicle C is stopped will be described. When the vehicle C turns while it is stopped, the inner wheels are already stopped. Therefore, when the speed of the vehicle C is equal to or lower than the second speed, the motor control unit 23 may prohibit the first turning control that applies the first negative torque to the inner wheels, and may execute the third turning control that enables turning with a turning radius smaller than that of the first turning control. Note that the above-described second speed is a speed lower than the first speed, and is set to, for example, 0 speed or substantially 0 speed. Therefore, when the speed of the vehicle C is equal to or lower than the second speed, it means that the vehicle C is stopped or almost stopped.

Specifically, when the speed of the vehicle C is equal to or lower than the second speed, the motor control unit 23 steers each of the four driving wheels 50 in the desired turning direction, and drives the four driving wheels in the desired turning direction. As a result, the vehicle C turns around the vehicle center point, and the turning performance of the vehicle C can be further improved.

As the third turning control, a mechanical brake may be used to stop the inner wheels without applying the negative torque to the inner wheels in the first turning control, and control may be performed to turn the vehicle C using the inner wheels as the fulcrums B.

In addition, in the above-described third turning control, the amount of turning of the vehicle C relative to the amount of operation of the steering wheel is larger than during normal turning control such as the second turning control. Therefore, unless the driver is made aware that the third turning control is to be performed, the large amount of turning may cause the driver to feel uncomfortable. Further, since the third turning control is basically performed while the vehicle is stopped, it is not necessary to immediately execute the turning control.

Therefore, the motor control unit 23 may execute the third turning control when a special execution instruction to execute the third turning control different from normal steering is received from the driver or the like. Specifically, for example, when a predetermined operation button provided in the vehicle interior is operated by the driver, or when the driver utters an instruction to execute (for example, "Turn right at this place"), the motor control unit 23 may accept the execution instruction and execute the third turning control.

As a result, since the driver recognizes that the third turning control is to be performed, it is possible to prevent the driver from feeling uncomfortable due to a large turning amount due to the third turning control. Note that the motor control unit 23 may execute the first turning control when receiving a special execution instruction instructing execution of the first turning control to apply the first negative torque, not limited to the third turning control.

Further, the motor control unit 23 may execute the third turning control after a predetermined time has elapsed after receiving the execution instruction. Although the predetermined time is set to a value that allows the driver to prepare for the third turning control with sufficient margin, it is not limited to this. That is, it can be said that the predetermined time is a predetermined waiting time.

This allows the driver to perform the third turning control involving a large amount of turning with plenty of time to spare.

The notification unit 24 can notify the occupant of information regarding motor control. for example. The notification unit 24 performs predetermined notification control to the vehicle occupant when executing the first turning control or the third turning control, such as the second turning control, in which the vehicle turns sharper than the normal turning control. Such predetermined notification control is, for example, control for notifying the occupant of the vehicle that predetermined motor control such as first turning control or third turning control is to be executed. Such notification is performed by notification by sound (audio) or by visual notification such as by turning on an indicator lamp, but the notification method is not limited to these.

This makes it possible for the driver to recognize that the predetermined motor control such as the first turning control and the third turning control is being performed, thereby making it difficult for the driver to feel uncomfortable due to performing the predetermined motor control. In particular, when the vehicle C is in a running state, it is possible to prevent the running state of the vehicle C from becoming unstable due to the turning control that is not recognized by the driver.

Next, a processing procedure executed by the motor control device 10 according to the embodiment will be described with reference to FIG. FIG. 4 is a flow chart showing an example of a processing procedure executed by the motor control device 10. As shown in FIG.

As shown in FIG. 4, the control unit 20 of the motor control device 10 determines whether or not the yaw rate of the vehicle C is equal to or higher than a predetermined yaw rate (step S10). The predetermined yaw rate is set, for example, to a value at which it can be determined that the vehicle C is skidding. That is, in step S10, it is determined whether or not the vehicle C skids.

When it is determined that the yaw rate of the vehicle C is not equal to or greater than the predetermined yaw rate (step S10, No), the control unit 20 determines whether or not the steering operation amount is equal to or greater than a predetermined operation amount (for example, a predetermined maximum amount) (step S11).

When it is determined that the steering operation amount is equal to or greater than the predetermined operation amount (step S11, Yes), the control unit 20 determines whether the speed of the vehicle C is less than the first speed (predetermined speed) (step S12). That is, steps S11 and S12 are processes for determining whether or not the driver desires a rapid turn while the vehicle C is running at a low speed or stopped.

When it is determined that the speed of the vehicle C is less than the first speed (step S12, Yes), the control unit 20 determines whether the speed of the vehicle C is equal to or lower than a second speed lower than the first speed (step S13). That is, step S13 is a process of determining whether or not the vehicle C is in a stopped state.

When it is determined that the speed of the vehicle C is not equal to or lower than the second speed (step S13, No), i.e., when the vehicle C is not in a stopped state but in a low speed running state, the control unit 20 executes first turning control to control the motor 60 so as to apply a first negative torque to the inner wheels (step S14). Subsequently, the controller 20 controls the outer ring motor 60 to apply a positive torque to the outer ring, more specifically, to increase the positive torque applied to the outer ring (step S15).

Next, the control unit 20 determines whether or not the inner ring has slipped (step S16). Specifically, in step S16, the control unit 20 determines whether or not the rotation speed acceleration of the inner ring motor 60 is equal to or less than a predetermined rotation speed acceleration.

Next, when it is determined that the slip state has occurred in the inner ring (step S16, Yes), the control section 20 executes the first turning control to control the motor 60 to apply the second negative torque to the inner ring (step S17). That is, the control unit 20 switches from application of the first negative torque D1 to application of the second negative torque D2.

On the other hand, when it is determined that the slip state does not occur in the inner ring (step S16, No), that is, when it is determined that the rotation speed acceleration of the inner ring motor 60 is not equal to or lower than the predetermined rotation speed acceleration, the control unit 20 skips the processing of step S17.

When it is determined that the yaw rate of the vehicle C is equal to or higher than the predetermined yaw rate (step S10, Yes), the control section 20 executes the second turning control (step S18). If it is determined that the steering operation amount is not equal to or greater than the predetermined operation amount (step S11, No), or if it is determined that the speed of the vehicle C is not less than the first speed (step S12, No), that is, if the driver does not desire a rapid turn, the control unit 20 proceeds to step S18 and executes the second turn control. In other words, when the speed of the vehicle C is equal to or higher than the first speed, the control unit 20 prohibits the execution of the first turning control and executes the second turning control.

When it is determined that the speed of the vehicle C is equal to or lower than the second speed (step S13, Yes), that is, when it is determined that the vehicle C is stopped, the control unit 20 determines whether or not a predetermined time has elapsed (step S19). When it is determined that the predetermined time has not passed (step S19, No), the control unit 20 repeats the process of step S19.

When it is determined that the predetermined time has passed (step S19, Yes), the control unit 20 performs the third turning control (step S20).

As described above, the motor control device 10 according to the embodiment includes the motor control section 23 . The motor control unit 23 individually controls the rotational drive motors 60 attached to the left and right drive wheels 50 of the vehicle C, respectively. Further, when the vehicle C turns, the motor control unit 23 executes a first turn control in which the motor 60 for the inner wheels is controlled to apply a first negative torque to the inner wheels of the left and right driving wheels 50 that are located inside when the vehicle turns, and after applying the first negative torque to the inner wheels, the motor 60 is controlled to apply a second negative torque smaller than the first negative torque to the inner wheels. Thereby, the turning performance of the vehicle C can be improved.

In the above-described embodiment, the motor control device 10 executes the first turning control and the third turning control when the driver desires a rapid turn and turns the vehicle C. However, the present invention is not limited to this, and the first turning control or the like may be executed, for example, when performing a normal turn that is not a rapid turn.

Moreover, in order to improve safety during rapid turning, the positive torque applied to the outer wheels in the first turning control may be as follows. For example, the positive torque applied to the outer wheel in the first turning control may be a torque amount smaller than the absolute value of the negative torque applied to the inner wheel, or a torque amount smaller than the positive torque applied to the outer wheel in the second turning control.

Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments so shown and described. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

REFERENCE SIGNS LIST 10 motor control device 20 control section 21 detection section 22 turn determination section 23 motor control section 24 notification section 50 drive wheel 60 motor

Claims (11)

A motor control device that individually controls rotational drive motors attached to left and right drive wheels of a vehicle,
When the vehicle turns, the motor control unit for executing a first turning control controls the motor for the inner wheels to apply a first negative torque to the inner wheel, which is the inner one of the left and right drive wheels when the vehicle turns, and after applying the first negative torque to the inner wheels, controls the motor to apply a second negative torque smaller than the first negative torque to the inner wheels.
with
The motor control unit
Prohibiting execution of the first turning control when the speed of the vehicle is equal to or higher than a first speed.
A motor control device characterized by: The motor control unit
The motor control device according to claim 1, wherein, after applying the first negative torque to the inner ring, the second negative torque is applied to the inner ring when it is determined that the inner ring has slipped. The motor control unit
3. The motor control device according to claim 1, wherein when applying negative torque to the inner wheel, the motor for the outer wheel is controlled so as to increase the positive torque applied to the outer wheel, which is the outer wheel of the left and right drive wheels when the vehicle turns. The motor control unit
The motor control device according to any one of claims 1 to 3 , wherein when the speed of the vehicle is equal to or higher than the first speed, second turning control is executed to control the motor so as to apply negative torque to the inner wheels within a range in which a slip state does not occur. The motor control unit
The motor control device according to any one of claims 1 to 4 , wherein when the speed of the vehicle is equal to or lower than a second speed that is lower than the first speed, a third turning control that enables turning with a turning radius smaller than that of the first turning control is executed. The motor control unit
The motor control device according to claim 5 , wherein the third turning control is executed when an execution instruction instructing execution of the third turning control different from normal steering is received. The motor control unit
7. The motor control device according to claim 6 , wherein the third turning control is executed after a predetermined time has elapsed since receiving the execution instruction. The motor control device according to any one of claims 5 to 7 , further comprising: a notification unit that performs predetermined notification control for an occupant of the vehicle when executing the first turning control or the third turning control. A motor control device that individually controls rotational drive motors attached to left and right drive wheels of a vehicle,
When the vehicle turns, the motor control unit for executing a first turning control controls the motor of the inner wheels so as to apply a first negative torque that generates a slip state to the inner wheels of the left and right driving wheels, which are located inside when the vehicle turns, and controls the motors so that after the inner wheels transition from the slip state generated by the application of the first negative torque to the grip state of gripping the road surface , a second negative torque smaller than the first negative torque is applied to the inner wheels.
A motor control device comprising : A motor control method for individually controlling rotational drive motors attached to left and right driving wheels of a vehicle , which is executed by a control device, comprising:
when the vehicle turns, a first turning control is executed in which the motor of the inner wheels is controlled to apply a first negative torque to the inner wheel, which is the inner one of the left and right drive wheels when the vehicle turns, and after applying the first negative torque to the inner wheels, the motor is controlled to apply a second negative torque smaller than the first negative torque to the inner wheels ;
The first turning control includes:
inhibiting execution if the speed of the vehicle is greater than or equal to a first speed;
A motor control method characterized by: A motor control method for individually controlling rotational drive motors attached to left and right driving wheels of a vehicle , which is executed by a control device, comprising:
When the vehicle turns, a motor control method comprising: controlling the motor of the inner wheels so as to apply a first negative torque for generating a slip state to the inner wheel of the left and right drive wheels that is located inside when the vehicle turns; and controlling the motor so as to apply a second negative torque smaller than the first negative torque to the inner wheels after the inner wheels transition from the slip state generated by the application of the first negative torque to the grip state of gripping the road surface .

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