WO2016043077A1 - Vehicle drive control device - Google Patents

Abstract

A vehicle drive control device of the present invention, in a vehicle provided with left and right motors (6, 6) that individually drive left and right drive wheels (2, 2), has a torque control means (30) that controls the torque of each motor (6) in accordance with a command torque through the use of a command current. The drive control device is provided with a motor temperature detection means (Sc) that respectively detects the temperatures of the left and right motors (6, 6) and a steering angle detection means (Sa) that detects the steering angle. The drive control device is further provided with a command current correction means (33) that, when the difference between the detected motor temperatures is at or above a threshold value and the steering angle is at or below a set value, corrects the command current so that output-torques output from the left and right motors (6, 6) will be the same torque with respect to the command torque applied to the torque control means (30).

Description

Vehicle drive control device Related applications

This application claims the priority of Japanese Patent Application No. 2014-188889 filed in Japan on September 17, 2014, and is incorporated herein by reference in its entirety.

The present invention relates to a drive control device for a vehicle that drives one of two front wheels, two rear wheels, or both of them, and is applied to, for example, an in-wheel electric vehicle or an on-board electric vehicle. Regarding technology.

Electric vehicles that drive wheels with electric motors and hybrid electric vehicles that combine electric motors with other prime movers are in practical use. In such an electric vehicle, a decrease in performance or abnormality of the motor for driving the vehicle greatly affects the running stability of the vehicle. In an electric vehicle, a technique for suppressing a decrease in running stability of a vehicle due to a decrease in performance of a motor or the like has been proposed.

Prior art 1 (Patent Document 1)
This technology suppresses the temperature rise of motors used in electric vehicles. Specifically, the increase in the coil temperature of the motor is observed, and when the temperature exceeds a predetermined temperature, the output of the motor starts to be limited, and the increase in the temperature of the motor is suppressed. The rate at which the motor output is limited is expressed by the following equation.
Formula: 1-{(signal value−reference value) / (limit value−reference value)}

According to this equation, when the signal value that is the motor temperature is the same value as the reference value, the value obtained by the above equation is “1”, and the motor output is not limited at all.
As the signal value becomes larger than the reference value, the value obtained by the above formula becomes smaller, and when the signal value becomes the same value as the limit value, that is, when the motor temperature becomes the temperature represented by the limit value. The value obtained by the above formula is “0”, and the motor output is completely “0”.

Prior art 2 (Patent Document 2)
When the temperature difference between the left and right motors is equal to or greater than a predetermined value, left / right temperature difference reduction control is performed to adjust the oil supply amount in a direction to reduce the temperature difference.

JP 2000-32602 A JP 2008-195233 A

In the prior art 1, when the temperature difference between the left and right motors occurs and the motor temperature does not reach the predetermined temperature, a drive torque difference due to the temperature difference between the left and right motors occurs. As a result, the running stability of the vehicle may be reduced.
For example, when the vehicle is turning, the turning outer wheel of the left and right wheels has a higher load and higher rotation than the turning inner wheel, and therefore the amount of heat generated by the motor of the turning outer wheel increases. There is also a difference between the left and right motor efficiency. Therefore, even when the same power is supplied to the left and right motors during straight running immediately after turning, a relatively large difference is generated in the driving force, and the balance is lost.

In the prior art 2, an adjustment device for adjusting the oil supply amount is required, which is expensive.

An object of the present invention is a vehicle including left and right motors that individually drive left and right drive wheels, and a vehicle capable of suppressing a decrease in running stability caused by a temperature difference between the left and right motors and reducing costs. The drive control device is provided.

According to the vehicle drive control device of the present invention, in a vehicle including left and right motors 6 and 6 that individually drive the left and right drive wheels 2 and 2, the torques of the motors 6 and 6 are commanded according to a given command torque. A vehicle drive control device having torque control means 30 controlled by current,
Motor temperature detecting means Sc for detecting the temperatures of the left and right motors 6 and 6 respectively;
Steering angle detection means Sa for detecting the steering angle of the vehicle;
When the temperature difference between the left and right motors 6 and 6 detected by the motor temperature detecting means Sc is not less than a threshold value and the steering angle detected by the steering angle detecting means Sa is not more than a set value, the torque control means 30 Command current correction means 33 for correcting the command current so that the output torque output from the left and right motors 6 and 6 is the same as the command torque applied to
It has.
The threshold value and the set value are determined based on results of tests and simulations, respectively.
For example, the threshold value is set to about 10 degrees to several tens of degrees at which the driving force is determined to be in an unbalanced state due to the temperature difference between the left and right motors. The set value is set to, for example, less than about 10 degrees (steering play angle) at which it is determined that the vehicle is traveling substantially straight.

According to this configuration, the torque control means 30 controls the torque of each motor 6 with the command current according to the command torque given from the host control means or the like. The motor temperature detecting means Sc detects the temperatures of the left and right motors 6 and 6, respectively. The steering angle detection means Sa detects the steering angle of the vehicle. When turning the vehicle, the outer wheel on the turning side is higher in load and rotation than the inner wheel on the turning side, so the balance between the left and right wheels is lost. Execute. In order to determine whether or not the vehicle is traveling substantially straight, the steering angle detection means Sa detects the steering angle of the vehicle. The command current correction means 33 determines, for example, whether or not the detected temperature difference between the left and right motors 6 and 6 is greater than or equal to a threshold value, and determines whether or not the steering angle detected in the determination that the temperature difference is equal to or greater than the threshold value judge.

When it is determined that the steering angle is equal to or less than the set value, that is, when it is determined that the vehicle is traveling substantially straight, the command current correction means 33 outputs torque from the left and right motors 6 and 6 equal to the command torque. The command current is corrected so that By the way, if there is no temperature difference between the left and right motors 6, 6, the relationship between the command current and the motor output torque is uniquely determined. If there is a temperature difference between the left and right motors, the relationship between the command current and the motor output torque differs for each temperature, that is, for each motor.

Therefore, the command current correction means 33 instructs the motor 6 on the higher temperature side than the motor 6 on the lower temperature side of the left and right motors 6 and 6 to make the output torque from the left and right motors 6 and 6 the same torque. Control is performed so that the current becomes relatively large. Thus, by making the output torques output from the left and right motors 6 and 6 the same torque, it is possible to suppress a decrease in running stability of the vehicle due to the temperature difference between the left and right motors 6 and 6. Further, according to this control, the output torque of the left and right motors 6 and 6 can be made the same by correcting the command current without adding a new device. Cost reduction can be achieved compared with the conventional technology required.

The command current correction means 33 determines whether or not the temperature difference between the left and right motors 6 and 6 is equal to or greater than a threshold value, and whether the steering angle detected by the determination equal to or greater than the threshold value satisfies a condition that is less than or equal to a set value. It is good also as having the amendment execution judgment part 33a which judges whether or not. The correction execution determination unit 33a determines whether or not the condition is satisfied at all times or intermittently.
When the command current correction unit 33 corrects the command current, if the correction execution determination unit 33a determines that the condition is not satisfied, the command current correction unit 33 stops correcting the command current. The control may be switched only to the control by the torque control means 30.
By switching to only the control by the torque control means 30 in this way, it is possible to improve both the left and right motor efficiency and improve the power consumption.

A rotation speed detection means 36 for detecting the rotation speed of each motor 6 is provided, and the command current correction means 33 provides a corrected command current according to the rotation speed detected by the rotation speed detection means 36 and the command torque. The command current correction map 33b has a recorded command current correction map 33b. When the command current correction means 33 determines that the condition is satisfied by the correction execution determination unit 33a, the command current correction map 33b uses the corrected command current recorded in the command current correction map 33b. The motors 6 may be controlled.
The command current correction map 33b is determined by the results of tests and simulations.

In this case, the command current correction means 33 controls each motor 6 according to the corrected command current recorded in the command current correction map 33b, so that the output torques of the left and right motors 6 and 6 can be made equal. Therefore, it is possible to suppress a decrease in traveling stability of the vehicle due to a temperature difference between the left and right motors 6 and 6.
Instead of the control using the command current correction map 33b, a relational approximate expression between the motor temperature and the actual output torque is obtained in advance by a test, simulation, or the like for the command torque. May be corrected.

The command current correction means 33 may correct the command current after performing a process of reducing the accelerator signal. By performing the process of reducing the accelerator signal before correcting the command current in this way, it is possible to suppress the temperature increase of the motor 6. Thereby, the load of the motor 6 can be reduced.

The motor 6 includes an in-wheel motor drive including the motor 6, a wheel bearing 4 that rotatably supports the drive wheel 2, and a speed reducer 7 that decelerates the rotation of the motor 6 and transmits the rotation to the wheel bearing 4. The device 8 may be configured. In the case of the in-wheel motor drive device 8, for example, the motor 6 tends to rotate at a higher speed than the motor drive device that does not include the speed reducer 7, and the running stability of the vehicle due to the temperature difference between the left and right motors 6 and 6 is increased. However, even when the motor 6 rotates at a high speed, the output torque of the left and right motors 6 and 6 is set to the same torque, so that the vehicle caused by the temperature difference between the left and right motors 6 and 6 can be reduced. A decrease in running stability can be suppressed.
The vehicle may be an on-board type vehicle in which the left and right motors 6 and 6 are respectively mounted on the vehicle body 1.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more of each claim in a claim is included in the present invention.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the present invention is defined by the appended claims (claims). In the accompanying drawings, the same component symbols in a plurality of drawings indicate the same parts.
It is a block diagram of the conceptual composition which shows the electric vehicle which is a vehicle concerning this embodiment by a top view. It is sectional drawing of the in-wheel motor drive device of the same electric vehicle. (A), (b) is a conceptual block diagram of the IPM motor of the electric vehicle. It is a block diagram of conceptual composition, such as an inverter device of the electric vehicle. It is a block diagram which shows the main structures etc. of the motor control part of the same electric vehicle. It is a block diagram which shows the main structures etc. of the motor control part. It is a figure which shows the relationship between a motor current and a motor output torque for every motor temperature. It is a figure which shows a command current correction map. It is a flowchart which shows determination of correction control of command current in steps. It is a figure showing execution judgment of amendment control of command current. (A), (b) is a figure which illustrates roughly the correction method of the command current of a left-right motor. It is a figure which shows schematically the system configuration | structure of the drive control apparatus of the vehicle which concerns on other embodiment of this invention by planar view.

A vehicle drive control apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a conceptual configuration showing the electric vehicle as the vehicle in a plan view. This electric vehicle is a four-wheeled vehicle in which the wheels 2 that are the left and right rear wheels of the vehicle body 1 are driving wheels, and the wheels 3 that are the left and right front wheels are steering wheels of driven wheels. Each of the wheels 2 and 3 serving as the driving wheel and the driven wheel has a tire and is rotatably supported by the vehicle body 1 via wheel bearings 4 and 5, respectively.

The wheel bearings 4 and 5 are abbreviated as “H / B” in FIG. The left and right wheels 2, 2 serving as driving wheels are driven by independent traveling motors 6, 6, respectively. The rotation of the motor 6 is transmitted to the wheel 2 via the speed reducer 7 and the wheel bearing 4. The motor 6, the speed reducer 7, and the wheel bearing 4 constitute an in-wheel motor drive device 8 that is one assembly part. Each wheel 2, 3 is provided with an electric or hydraulic brake 9, 10. Further, the wheels 3 and 3 which are the steering wheels which are the left and right front wheels can be steered via the steering mechanism 11 and are steered by a steering means 12 such as a steering wheel.

FIG. 2 is a cross-sectional view of the in-wheel motor drive device. Each in-wheel motor drive device 8 includes a motor 6, a speed reducer 7, and a wheel bearing 4, and a part or all of these are disposed in the wheel. The rotation of the motor 6 is transmitted to the drive wheel 2 via the speed reducer 7 and the wheel bearing 4. A brake rotor BR constituting the brake 9 is fixed to the flange portion of the hub wheel 4 a of the wheel bearing 4, and the brake rotor BR rotates integrally with the drive wheel 2. The motor 6 is, for example, an embedded magnet type synchronous motor in which a permanent magnet is built in the core portion of the rotor 6a. The motor 6 is a motor in which a radial gap is provided between a stator 6b fixed to the housing HS and a rotor 6a attached to the rotation output shaft KS.

FIG. 3 is a conceptual configuration diagram of the IPM motor of the electric vehicle.
As shown in FIG. 3A, when the motor driving the wheel is an IPM motor, that is, an embedded magnet type synchronous motor, the magnetic resistance in the q-axis direction orthogonal to the d-axis direction, which is the magnet axis, is smaller. Thus, a salient pole structure is formed, and the q-axis inductance Lq is larger than the d-axis inductance Ld.
Due to this saliency, reluctance torque Tr can be used in addition to magnet torque Tm, and high torque and high efficiency can be achieved.
Magnet torque Tm: Torque generated by attracting and repelling the magnetic field generated by the permanent magnet of the rotor and the rotor magnetic field generated by the winding.
Reluctance torque Tr: A torque generated when a salient pole portion of a rotor is attracted to a rotating magnetic field by a winding.

The total torque generated by the motor is as follows.
T = p × {Ke × Iq + (Ld−Lq) × Id × Iq} = Tm + Tr
p: number of pole pairs Ld: d-axis inductance of motor Lq: q-axis inductance of motor Ke: effective value of motor induced voltage constant

As shown in FIG. 3 (b), there is a vector control method in which the primary current Ia flowing through the IPM motor is separated into a torque generation current q-axis current Iq and a magnetic flux generation current d-axis current Id and can be controlled independently. It is well known.
Id = −Ia × sin β
Iq = Ia × cos β
β: Current advance angle Here, the motor voltage equation is expressed as follows.

ω: motor angular velocity Ke: induced voltage constant Id: d-axis current Iq: q-axis current Ld: d-axis inductance Lq: q-axis inductance R: armature resistance p: differential operator

The three-phase motor currents Iu, Iv, Iw flowing in the respective phases of the three-phase coil of the permanent magnet motor are converted into actual currents Id, Iq flowing in the d-axis and the q-axis using the rotation angle sensor Θ.

FIG. 4 is a block diagram of a conceptual configuration of the inverter device and the like of this electric vehicle. Hereinafter, description will be made with reference to FIG. 1 as appropriate. The electric vehicle includes an ECU 21 that is an electric control unit that controls the entire vehicle, and an inverter device 22 that controls the traveling motor 6 in accordance with an acceleration / deceleration command of the ECU 21. The ECU 21 includes a computer, a program executed by the computer, various electronic circuits, and the like.

The ECU 21 is roughly divided into a general control unit 21a and a power running / regenerative control command unit 21b. The power running / regeneration control command unit 21b outputs an acceleration command (drive) output from the accelerator operation unit 16, a deceleration command (regeneration) output from the brake operation unit 17, and a steering angle sensor Sa (steering angle detection means). From the turning command, an acceleration / deceleration command to be given to the traveling motors 6, 6 for the left and right wheels 2, 2 is generated as a command torque and output to the inverter device 22.

In addition to the above, the power running / regenerative control command unit 21b outputs an acceleration / deceleration command to be output, for example, to the rotation sensors 4a provided on the wheel bearings 4, 5 (FIG. 1) of the wheels 2, 3 (FIG. 1). 5a (FIG. 1) may have a function of correcting using information on the tire rotation speed obtained from 5a (FIG. 1) and information on each vehicle-mounted sensor.
The power running / regeneration control command unit 21 b gives a command flag for switching between power running and regeneration to the torque control means 30 of the motor control unit 29.

The accelerator operation unit 16 includes an accelerator pedal 16a and a sensor 16b that detects an amount of depression of the accelerator pedal 16a and outputs an acceleration command. The brake operation unit 17 includes a brake pedal 17a and a sensor 17b that detects a depression amount of the brake pedal 17a and outputs a deceleration command.
The general control unit 21a outputs a deceleration command output from the brake operation unit 17 to the brake controller 23, a function to control various auxiliary machine systems 31 (FIG. 1), for example, an input command from a console operation panel or the like. A function of processing, a function of causing the display means 32 (FIG. 1) to perform display, and the like. The auxiliary machine system 31 is, for example, an air conditioner, a light, a wiper, GPS, an air bag, or the like.

The inverter device 22 includes a power circuit unit 28 provided for each motor 6 and a motor control unit 29 that controls the power circuit unit 28. Although not shown, the inverter device 22 is provided for each motor 6. The motor control unit 29 may be provided in common for each power circuit unit 28 or may be provided separately. Even when the motor control unit 29 is provided in common for each power circuit unit 28, the left and right motors 6 and 6 can be controlled independently so that the torques of the motors 6 and 6 are different from each other. The motor control unit 29 has a function of outputting information such as detection values and control values related to the in-wheel motor drive device 8 included in the motor control unit 29 to the ECU 21.

The power circuit unit 28 includes an inverter 28a that converts the DC power of the battery 19 into three-phase AC power used for powering and regeneration of the motor 6, and a PWM driver 28b that controls the inverter 28a.
The motor 6 is a three-phase synchronous motor. The motor 6 is provided with a rotation angle detecting means 36 for detecting a rotation angle as an electrical angle of the rotor 6a (FIG. 2) of the motor 6. The inverter 28a is composed of a plurality of semiconductor switching elements, and the PWM driver 28b performs pulse width modulation on the input current command and gives an on / off command to each of the semiconductor switching elements.

The motor control unit 29 is configured by an electronic circuit such as a computer having a processor, a ROM having a program executed by the processor, and a RAM, and has a torque control means 30 as a basic control unit. The torque control means 30 converts it into a current command in accordance with an acceleration (power running) / deceleration (regeneration) command based on a command torque given from the ECU 21 which is the host control means, and gives a current command to the PWM driver 28b of the power circuit unit 28. . Switching between acceleration and deceleration is performed by a command flag from the power running / regenerative control command unit 21b of the ECU 21.

The torque control means 30 has a power running control unit 30a and a regeneration control unit 30b, and either the power running control unit 30a or the regeneration control unit 30b is selected by the command flag. When the power running control unit 30a is selected by the command flag, the power running control unit 30a increases the power running command torque as the depression amount of the accelerator pedal 16a increases. When the regeneration control unit 30b is selected by the command flag, the regeneration control unit 30b increases the regeneration command torque as the amount of depression of the brake pedal 17a increases.

The torque control means 30 generates a command current to the motor 6 using a preset torque map based on the command torque and command flag given from the ECU 21. The torque control means 30 controls the motor 6 by PI control so that the actual detection value obtained by the current detection means Sb for the drive current applied to the motor 6 matches the command current.

The drive control apparatus for an electric vehicle includes motor temperature detection means Sc, steering angle sensor Sa as steering angle detection means, and command current correction means 33. The command current correction means 33 has a correction execution determination unit 33a and a command current correction map 33b described later.
The motor temperature detection means Sc is a means for detecting the temperatures of the left and right motors 6 and 6, respectively. As shown in FIG. 2, in the stator 6b of each motor 6, the motor temperature detection means Sc is provided in the motor coil, for example. As the motor temperature detection means Sc, for example, a thermistor is used. The temperature of the motor 6 can be detected by fixing the thermistor to the motor coil.

The steering angle sensor Sa detects a steering angle that is a rotation angle of, for example, a steering wheel of the electric vehicle. When the electric vehicle is turning, the outer turning wheel has a higher load and higher rotation than the inner turning wheel, so this control is executed when the electric vehicle is traveling substantially straight. In order to determine whether or not the electric vehicle is traveling substantially straight, a steering angle is detected by a steering angle sensor Sa.
The command current correction means 33 is provided in the motor control unit 29, and when the conditions described later are satisfied, the output torque output from the left and right motors 6 and 6 is the same as the command torque given to the torque control means 30. The command current is corrected so that the torque is obtained.

FIG. 5 is a block diagram showing a main configuration and the like of the motor control unit 29.
The motor control unit 29 is a means for controlling the motor drive current, and includes a torque command unit 34. The torque command unit 34 is provided in the torque control unit 30 in the motor control unit 29. The torque command unit 34 uses the torque map based on the detected value detected by the current detection means Sb for the drive current applied to the motor 6 and the command torque based on the acceleration / deceleration command generated by the power running / regenerative control command unit 21b of the ECU 21. Thus, a corresponding command current is generated. The direction of the command current is switched by the command flag.

The torque control means 30 obtains the rotation angle of the rotor 6a (FIG. 2) of the motor 6 from the rotation angle sensor 36 and performs vector control. Here, the motors 6 and 6 provided on the left and right rear wheels 2 and 2 (FIG. 1) of the vehicle body have different torque generation directions during power running and during regeneration. When the motor 6 is viewed from the direction of the output shaft, the left rear wheel driving motor 6 generates torque in the CW direction, and the right rear wheel driving motor 6 generates torque in the CCW direction (left The right side is determined by the direction seen from the rear of the vehicle). Torques generated by the left and right motors 6 and 6 are transmitted to the tire by reversing the torque direction via the speed reducer 7 and the wheel bearing 4. Further, the direction of torque generation during regeneration in the motor 6 for the left and right tires is different from the direction of torque generation during power running.

For the torque map, a corresponding command torque is calculated from the maximum torque control table according to the accelerator signal and the motor speed. The torque command unit 34 generates a primary current (Ia) and a current advance angle (β) of the motor 6 based on the calculated command torque. The torque command unit 34 generates two command currents, a d-axis current (field component) O_Id and a q-axis current O_Iq, based on the values of the primary current (Ia) and the current advance angle (β).

The current PI control unit 35 is a two-phase current calculated by the three-phase / two-phase conversion unit 37 from the values of the d-axis current O_Id and q-axis current O_Iq output from the torque command unit 34 and the motor current and the rotor angle. Control amounts Vd and Vq based on voltage values by PI control are calculated from Id and Iq. The three-phase / two-phase conversion unit 37 obtains the following formula Iv = − (Iu + Iw) from the detected values of the u-phase current (Iu) and the w-phase current (Iw) of the motor 6 detected by the current detection means Sb. A v-phase current (Iv) is calculated and converted from a three-phase current of Iu, Iv, and Iw to a two-phase current of Id and Iq.

The rotor angle of the motor 6 used for this conversion is acquired from the rotation angle sensor 36. The two-phase / three-phase converter 38 converts the input two-phase control amounts Vd, Vq and the rotor angle into three-phase PWM duties Vu, Vv, Vw. The power converter 39 performs PWM control of the inverter 28a (FIG. 4) according to the PWM duties Vu, Vv, and Vw, and drives the motor 6.

The command current correction means 33 is such that the temperature difference ΔT between the left and right motors 6 and 6 detected by the motor temperature detection means Sc is not less than a threshold value, and the steering angle detected by the steering angle sensor Sa (FIG. 4) is a set value. It is determined whether or not the following conditions are satisfied. The command current correcting means 33 corrects the command current so that the output torques output from the left and right motors 6 and 6 are the same as the command torque given to the torque control means 30 when the above conditions are satisfied. To do.

FIG. 6 is a block diagram showing the command current correction means 33 and the like. The command current correction unit 33 includes a correction execution determination unit 33a and a command current correction map 33b. The correction execution determination unit 33a receives the temperatures T1 and T2 of the left and right motors 6 and 6 (FIG. 1) detected by the motor temperature detection means Sc (FIG. 4), and is detected by the steering angle sensor Sa (FIG. 4). The steering angle θ is input. The correction execution determination unit 33a determines whether or not the temperature difference ΔT between the input temperatures T1 and T2 satisfies a condition that is equal to or greater than a threshold value and the steering angle θ is equal to or less than a set value.

By the way, if there is no temperature difference between the left and right motors 6 and 6 (FIG. 1), the relationship between the command current and the output torque of the motor 6 is uniquely determined. FIG. 7 is a diagram illustrating the relationship between the motor current and the motor output torque for each motor temperature. If there is a temperature difference between the left and right motors 6 and 6 (FIG. 1), the relationship between the command current and the motor output torque is different for each temperature, that is, for each motor. When the same command torque is applied to the left and right motors 6 and 6 (FIG. 1), the output torque decreases as the motor temperature increases.

That is, when the motor temperature rises, the motor efficiency decreases. This is because the motor stator generates heat when a current flows through the coil. Further, the resistance increases and the power consumption increases.
When the motor temperature rises, the speed reducer efficiency decreases. This is because when the motor temperature rises, the reduction gear loss increases, the reduction gear transmission efficiency decreases, and the power performance of the vehicle decreases.
For the above reasons, when the same command torque is applied to the left and right motors 6 and 6 (FIG. 1), the output torque decreases as the motor temperature increases.

Therefore, as shown in FIG. 6, when the command current correction unit 33 determines that the condition is satisfied by the correction execution determination unit 33 a, each of the motors 6, 6 is determined based on the corrected command current recorded in the command current correction map 33 b. (FIG. 1) is controlled. The command current correction map 33b includes temperature T1 and T2 of the left and right motors 6 and 6 (FIG. 1) detected by the motor temperature detection means Sc, command torque from the ECU 21 (FIG. 4), and rotation speed detection means. The rotational speed ω of each motor 6 detected by the rotation angle sensor 36 (FIG. 4) is input.

FIG. 8 is a diagram showing a command current correction map 33b. In this command current correction map 33b, the command current corrected according to the motor rotation speeds ω_0, ω_1,..., Ω_m and the command torques Trq_0, Trq_1,. Further, a plurality of command current correction maps 33b are provided at regular intervals of the motor temperature (for example, 5 degrees, 10 degrees,... 180 degrees).

FIG. 9 is a flowchart showing step-by-step determination of command current correction control. Hereinafter, description will be made with reference to FIGS. The correction execution determination unit 33a determines whether or not the absolute value of the value obtained by subtracting the temperature T2 of the right motor 6 from the temperature T1 of the left motor 6 is equal to or higher than the temperature threshold A (condition (1): step S1). If the determination is NO (step S1: NO), the correction execution determination unit 33a determines whether the absolute value of the value obtained by subtracting the temperature T2 from the temperature T1 is equal to or lower than the temperature threshold B (step S2). However, the temperature threshold A> the temperature threshold B, and the temperature threshold A and the temperature threshold B have a difference of, for example, about 10 degrees or more.

FIG. 10 is a diagram showing the execution determination of the command current correction control. As shown in FIGS. 9 and 10, when it is determined that the temperature difference is equal to or less than the temperature threshold B (step S <b> 2: YES), the command current correction control is stopped and switched to only the control by the torque control means 30. If it is determined that the temperature difference is greater than the temperature threshold B (step S2: NO), the process returns to step S1. As described above, the correction execution determination unit 33a determines the execution of the command current correction control having the hysteresis characteristic of the temperature difference by setting the two temperature thresholds A and B.

Determination that the temperature difference ΔT is equal to or greater than the temperature threshold A, that is, satisfies the condition (1) for determining whether the driving force is in an unbalanced state due to the temperature difference between the left and right motors 6 and 6 (step S1: YES). Thus, the correction execution determination unit 33a determines whether or not the steering angle θ from the steering angle sensor Sa (FIG. 4) is equal to or smaller than the set value a, that is, whether the vehicle is traveling substantially straight (condition (2): Step S3). If this condition (2) is not satisfied (step S3: NO), the command current correction control is stopped and only the control by the torque control means 30 is switched. The correction execution determination unit 33a permits execution of the command current correction (step S4) when the condition (1) and the condition (2) are satisfied (step S3: YES). Then, it returns to step 1. This follow is continued while the command current correction is performed, and only the control by the torque control 30 is performed when either the temperature difference ΔT condition (1) or the steering angle condition (2) is not satisfied. To.

FIG. 11 is a diagram schematically illustrating a method for correcting the command current of the left and right motors.
As shown in FIG. 11 (a), for example, when the temperature of the left motor is 50 ° C. and the temperature of the right motor is 50 ° C., the command current correction means 33 (FIG. 6) includes the left and right motors 6 and 6 (FIG. 1). ) Is determined to be equal to or less than the temperature threshold B, and only the control by the torque control means 30 (FIG. 6) is performed. In this case, the torque control means 30 (FIG. 6) outputs the command current to the left and right motors 6 and 6 (FIG. 1) without correction.

As shown in FIG. 11B, for example, when the temperature of the left motor is 60 ° C. and the temperature of the right motor is 90, and when the steering angle is smaller than the set value, the command current correction means 33 (FIG. 6) The command current is corrected after processing to reduce the accelerator signal. In the process of reducing the accelerator signal, the command torque supplied from the ECU 21 is limited without changing the acceleration / deceleration command input to the ECU 21 (FIG. 4).

As a correction method, in order to make the output torque from the left and right motors the same torque, the command current to the motor with high temperature is made larger than the command current to the motor with low temperature. However, in order to suppress further temperature rise of the motor having a high temperature, the command current correction means 33 (FIG. 4) corrects the command current after limiting the command torque to the left and right motors, respectively.

According to the drive control apparatus described above, the command current correcting unit 33 determines that the correction execution determining unit 33a satisfies the conditions (1) and (2), and the left and right motors 6, 6 with respect to the command torque. To correct the command current so that the output torques respectively output from the motors become the same torque. For this reason, it is possible to suppress a decrease in running stability of the vehicle due to a temperature difference between the left and right motors 6 and 6.
Further, according to this control, the output torque of the left and right motors 6 and 6 can be made the same by correcting the command current without adding a new device. Cost reduction can be achieved compared with the conventional technology required.

When the command current correction unit 33 corrects the command current, if the correction execution determination unit 33a determines that the condition is not satisfied, the command current correction unit 33 stops correcting the command current, and the torque control unit Only the control by 30 is switched. By switching to only the control by the torque control means 30 in this way, it is possible to improve both the left and right motor efficiency and improve the power consumption.

The command current correcting means 33 corrects the command current after performing a process of reducing the accelerator signal. By performing the process of reducing the accelerator signal before correcting the command current in this way, it is possible to suppress the temperature increase of the motor 6. Thereby, the load of the motor 6 can be reduced.

Another embodiment will be described.
In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.
As shown in FIG. 12, the vehicle may be an on-board vehicle in which left and right motors 6 and 6 are mounted on the vehicle body 1, respectively. The left and right motors 6, 6 mounted on the vehicle body 1 are connected to the wheel bearing 4 via the drive shaft DF, respectively, and transmit the rotation of the motor 6 to the drive wheel 2. The drive shaft DF includes constant velocity joints at both ends thereof so that rotation can be transmitted to the drive wheels 2 at a constant velocity even when the vehicle body 1 is bound / rebound.

As the vehicle, a two-wheel independent drive vehicle that independently drives the left and right front wheels may be applied. Further, as the vehicle, a four-wheel independent drive vehicle that drives the left and right front wheels independently and drives the left and right rear wheels independently may be applied.
In an in-wheel motor drive device, a cycloid reducer, a planetary reducer, a two-axis parallel reducer, and other reducers can be applied, and even a so-called direct motor type that does not employ a reducer. Good.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily consider various changes and modifications within the obvious range by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the present invention as defined by the appended claims.

1 ... car body 2 ... wheel (drive wheel)
DESCRIPTION OF SYMBOLS 4 ... Wheel bearing 6 ... Motor 7 ... Reducer 8 ... In-wheel motor drive device 30 ... Torque control means 33 ... Command current correction means 33a ... Correction execution determination part 33b ... Command current correction map Sa ... Steering angle sensor (steering angle) Detection means)
Sc: Motor temperature detection means

Claims (7)

1. In a vehicle including left and right motors for individually driving left and right drive wheels, a vehicle drive control device having torque control means for controlling the torque of each motor with a command current in accordance with a given command torque,
   Motor temperature detection means for respectively detecting the temperature of the left and right motors;
   Steering angle detection means for detecting the steering angle of the vehicle;
   When the temperature difference between the left and right motors detected by the motor temperature detecting means is not less than a threshold value and the steering angle detected by the steering angle detecting means is not more than a set value, the command torque applied to the torque control means is On the other hand, command current correction means for correcting the command current so that the output torque output from the left and right motors is the same torque,
   A vehicle drive control device comprising:
2. 2. The vehicle drive control device according to claim 1, wherein the command current correction means determines whether or not a temperature difference between left and right motors is equal to or greater than a threshold value, and sets a steering angle detected by the determination equal to or greater than the threshold value. A vehicle drive control device having a correction execution determination unit that determines whether or not a condition equal to or less than a value is satisfied.
3. 3. The vehicle drive control device according to claim 2, wherein when the command current is corrected by the command current correction unit, the command current correction unit is determined when the correction execution determination unit determines that the condition is not satisfied. A vehicle drive control device that stops the correction of the command current by and switches only to control by the torque control means.
4. 4. The vehicle drive control device according to claim 2, further comprising: a rotation speed detection unit that detects a rotation speed of each motor, wherein the command current correction unit includes a rotation speed detected by the rotation speed detection unit, and A command current correction map that records a corrected command current according to the command torque is provided, and the command current correction unit includes the command current correction map when the correction execution determination unit determines that the condition is satisfied. A vehicle drive control device that controls each of the motors according to the corrected command current recorded.
5. 5. The vehicle drive control apparatus according to claim 1, wherein the command current correction unit corrects the command current after performing a process of reducing an accelerator signal. 6. .
6. 6. The vehicle drive control device according to claim 1, wherein the motor is configured to reduce the rotation of the motor, a wheel bearing that supports the drive wheel in rotation, and the motor. The vehicle drive control apparatus which comprises the in-wheel motor drive device containing the reduction gear transmitted to the said wheel bearing.
7. 6. The vehicle drive control device according to claim 1, wherein the vehicle is an on-board type vehicle in which the left and right motors are mounted on a vehicle body.
   
   

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