JP7393308B2 - motor lock control device - Google Patents

Description

The present invention relates to a motor lock control device that performs motor lock control of a vehicle when an electric motor that is a drive source of the vehicle enters a motor lock state.

The driving force control device described in Patent Document 1 prohibits the electric motor from generating torque and further brakes when the motor is locked when starting on a slope and the temperature of the inverter circuit is higher than a predetermined temperature. performs motor lock control to prevent the vehicle from rolling. Thereafter, when the temperature of the inverter circuit reaches a predetermined temperature or higher, the motor lock control is released.

JP2009-232485A

By the way, when the motor locks up on an uphill road, the driver may want to slide the vehicle down, depending on the circumstances around the vehicle. However, in the driving force control device described in Patent Document 1, once the motor lock control is performed, the motor lock control is not released until the temperature of the inverter circuit reaches a predetermined temperature or higher. On the other hand, if the driver operates the shift lever to switch gears to neutral or reverse, it is considered possible to lower the vehicle before the temperature of the inverter circuit reaches a predetermined temperature or higher. However, such operations are extremely troublesome for the driver.

Therefore, an object of the present invention is to provide a motor lock control device that can easily release motor lock control.

The motor lock control device according to the present invention prohibits the generation of torque of the electric motor and activates the electric parking brake of the vehicle when the electric motor that is the drive source of the vehicle enters a motor lock state on an uphill road. A control unit that performs motor lock control is provided, and when the accelerator is turned off while the motor lock control is being performed, the control unit releases the motor lock control.

With this motor lock control device, when the electric motor enters the motor lock state on an uphill road, motor lock control is performed that prohibits the generation of torque in the electric motor and activates the electric parking brake, thereby suppressing electric motor failure. can do. Here, when the driver wants to slide down the motor-locked vehicle on an uphill road, the driver consciously or unconsciously releases the accelerator. Therefore, this motor lock control device releases the motor lock control when the accelerator is turned off while the motor lock control is being performed. In this way, the motor lock control can be released by an operation performed consciously or unconsciously by the driver when the driver wants to lower the vehicle, so the motor lock control can be easily released.

When the accelerator is turned off while the motor lock control is being performed, the control unit releases the motor lock control and controls the electric motor to drive so that the vehicle moves backward at a constant speed. In this motor lock control device, when the accelerator is turned off while motor lock control is being performed on an uphill road, motor lock control is released and the electric motor is driven and controlled so that the vehicle moves backward at a constant speed. . As a result, it is possible to prevent the vehicle from sliding down at an excessive speed, such as when the slope angle of the slope road is large.

The control unit does not perform motor lock control when the electric motor is in a motor lock state on a flat road or a downhill slope. A possible case where the motor locks up on a flat road or a downhill road is when the wheels of the vehicle are caught on a protrusion such as a curb. In such a case, the driver is considered to be intending to move the vehicle forward, unlike when the motor is locked on an uphill road. Therefore, this motor lock control device does not perform motor lock control when the motor is locked on a flat road or on a downhill slope. Thereby, the electric motor can be driven according to the driver's intention.

According to the present invention, it is possible to perform motor lock control that allows easy release of motor lock control.

FIG. 2 is a block diagram showing the functional configuration of a motor lock control device according to an embodiment. It is a schematic diagram of a vehicle. It is a flow chart which shows processing operation of a motor lock control device concerning an embodiment. 5 is a time chart for explaining motor lock control. 5 is a time chart for explaining motor lock control.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements are given the same reference numerals and redundant description will be omitted.

As shown in FIGS. 1 and 2, a motor lock control device 2 according to this embodiment is mounted on a vehicle 1. As shown in FIGS. The motor lock control device 2 includes an electric motor 3 that is a drive source of the vehicle 1, an electric parking brake 4 of the vehicle 1, and a control section 10. The vehicle 1 may be any vehicle that uses at least the electric motor 3 as a driving source. For example, it may be an electric vehicle that uses only the electric motor 3 as a driving source, or it may be an electric vehicle that uses both the electric motor 3 and an engine (not shown) as a driving source. A hybrid vehicle may be used as a driving source.

The electric motor 3 has an output shaft (not shown) that is connected directly or indirectly to the drive wheels of the vehicle 1, and when supplied with current, rotates the output shaft to drive the vehicle 1. This is a motor that rotates the wheels. The electric motor 3 is driven and controlled by a control unit 10 . The electric motor 3 may be a motor generator that can perform both power running and regeneration. As the electric motor 3, various known electric motors can be used.

The electric parking brake 4 is a brake for maintaining the vehicle 1 in a stopped state. The electric parking brake 4 is driven and controlled by a control unit 10 . As the electric parking brake 4, various known electric parking brakes can be used.

The control section 10 is an electronic control unit (ECU) including a CPU, ROM, RAM, and the like. The control unit 10 executes various controls by loading programs stored in the ROM into the RAM and executing them on the CPU. Each of the control sections 10 may be composed of a plurality of electronic control units, or may be composed of a single electronic control unit.

The control unit 10 is electrically connected to the electric motor 3 and the electric parking brake 4, and drives and controls the electric motor 3 and the electric parking brake 4. The control unit 10 includes a vehicle information acquisition unit 11 , a road surface gradient acquisition unit 12 , an electric motor control unit 13 , an electric parking brake control unit 14 , and a motor lock control unit 15 .

The vehicle information acquisition unit 11 acquires various information about the vehicle 1. Various pieces of information about the vehicle 1 that the vehicle information acquisition unit 11 acquires are referred to as vehicle information. The vehicle information acquisition section 11 may be composed of one vehicle information acquisition section 11 or a plurality of vehicle information acquisition sections 11. The vehicle information acquisition unit 11 acquires, as vehicle information, accelerator opening, parking brake operation, rotation speed of the electric motor 3 (rotation speed of the output shaft), weight of the vehicle 1 (hereinafter referred to as "vehicle weight"), and transmission (non-transmission). (shown) (hereinafter referred to as "gear ratio"), differential gear gear ratio (hereinafter referred to as "diff ratio"), effective radius of tires (not shown) of vehicle 1, front projected area of vehicle 1, etc. get.

The accelerator opening degree can be acquired based on, for example, a signal from an accelerator pedal sensor (not shown) provided on a shaft portion of an accelerator pedal (not shown) of the vehicle 1.

The parking brake operation can be obtained based on a signal from a brake sensor (not shown) provided on the parking brake button or parking brake lever of the vehicle 1, for example.

The rotation speed of the electric motor 3 can be obtained based on a signal from a rotary encoder (not shown) provided on the output shaft of the electric motor 3, for example.

The vehicle weight can be acquired based on, for example, a signal from a weight sensor (not shown) that detects the weight of the cargo loaded on the vehicle 1, a signal from an acceleration sensor (not shown) that detects the acceleration of the vehicle 1, etc. . In other words, the weight of the vehicle when there is no cargo is registered in the memory in advance, and the weight of the cargo detected by the weight sensor is added to the vehicle weight read from the memory to obtain the vehicle weight. Further, the vehicle weight can be obtained by estimating the vehicle weight from the acceleration detected by the acceleration sensor when the vehicle 1 is accelerated or decelerated.

The gear ratio of the transmission can be obtained, for example, based on a signal from a transmission ECU (not shown) that automatically changes gears of the transmission.

Since the differential ratio of the differential gear, the effective radius of the tires, and the front projected area of the vehicle 1 do not change significantly depending on the driving condition, for example, these information may be registered in advance in a memory and then read from this memory. It can be obtained by

The road surface slope acquisition unit 12 detects the slope of the road surface on which the vehicle 1 is traveling. The road surface slope acquisition unit 12 detects a slope angle as the slope of the road surface. Furthermore, the road surface gradient acquisition unit 12 may detect any one of an uphill road, a flat road, and a downhill road as the road surface gradient. The slope of the road surface can be acquired based on a signal from an acceleration sensor (not shown) mounted on the vehicle 1, for example.

The electric motor control unit 13 drives and controls the electric motor 3 based on the accelerator opening degree acquired by the vehicle information acquisition unit 11. The accelerator opening degree acquired by the vehicle information acquisition unit 11 becomes the driver's requested torque for the electric motor 3. Therefore, the electric motor control unit 13 drives and controls the electric motor 3 so that the torque generated in the electric motor 3 corresponds to the torque requested by the driver.

The electric parking brake control unit 14 drives and controls the electric parking brake 4 based on the parking brake operation acquired by the vehicle information acquisition unit 11.

The motor lock control unit 15 performs motor lock control when the electric motor 3 is in a motor lock state on an uphill road. Whether or not the road is an uphill slope can be determined, for example, based on the slope of the road surface detected by the road surface slope acquisition unit 12. The motor lock state means that the torque generated by the electric motor 3 is lower than the running resistance torque of the vehicle 1, and the electric motor 3 is generating torque under the drive control of the electric motor control unit 13, but the electric motor 3 is A state in which it is not rotating or is not rotating at all. Whether or not the motor is in the locked state can be determined based on, for example, the control information of the electric motor control unit 13 and the rotation speed of the electric motor 3 acquired by the vehicle information acquisition unit 11. The motor lock control is a control for reducing the load on the electric motor 3 in the motor lock state, and is a control for prohibiting the electric motor 3 from generating torque and operating the electric parking brake 4. The running resistance torque of the vehicle 1 is the running resistance of the vehicle 1 converted into the torque of the electric motor 3.

As shown in FIG. 2, the running resistance F _res of the vehicle 1 when the vehicle 1 is running with the driving force F _P is, for example, the rolling resistance F _rot of the wheels of the vehicle 1 and the air resistance F _Air of the vehicle 1. and the gradient resistance F _Grad . That is, F _res =F _rot +F _Air +F _Grad . Note that the running resistance F _res of the vehicle 1 may be a part of these resistances, or may include other resistances.

Here, the vehicle mass is m, the gravitational acceleration is g, the rolling resistance coefficient is μ _rot , the air density is ρ, the frontal projected area of the vehicle 1 is A, the air resistance coefficient is C _d , and the slope of the road surface is θ (or Grad). In this case, rolling resistance F _rot is expressed, for example, by the following formula (1), air resistance F _Air is expressed by the following formula (2), and gradient resistance F _Grad is expressed, for example, by the following formula ( 3).

When the effective radius of the tires of the vehicle 1 is r _wh , the gear ratio of the transmission is G _t , and the differential gear ratio of the differential gear is G _d , the running resistance torque T _res of the vehicle 1 is, for example, T _res = (F _res × r _wh )/G _d /G _t .

As described above, when the electric motor 3 enters the motor lock state on an uphill road, the electric motor 3 may become overloaded and fail, so the motor lock control unit 15 performs motor lock control. This reduces the load on the electric motor 3.

On the other hand, the motor lock control unit 15 does not perform motor lock control when the electric motor 3 is in the motor lock state on a flat road or a downhill slope. That is, while allowing the electric motor 3 to generate torque, the electric parking brake 4 is not operated.

The motor lock control unit 15 controls the torque generated in the electric motor 3 when the motor lock control is not performed, such as when the accelerator opening increases, to the running resistance torque of the vehicle 1. If it becomes larger than , motor lock control is released. Releasing the motor lock control means allowing the electric motor 3 to generate torque and canceling the operation of the electric parking brake 4.

Further, the motor lock control unit 15 releases the motor lock control when the accelerator is turned off while the motor lock control is being performed. That is, the motor lock control is performed when the electric motor 3 is in a motor lock state on an uphill road, but when the driver releases the accelerator in such a motor lock state, the motor lock control is released. Accelerator off refers to a state in which the accelerator pedal is not depressed. Whether or not the accelerator has been turned off can be determined, for example, based on the accelerator opening degree acquired by the vehicle information acquisition unit 11.

When the accelerator is turned off while the motor lock control is being performed, the motor lock control unit 15 not only releases the motor lock control but also drives the electric motor 3 so that the vehicle 1 moves backward at a constant speed. May be controlled. In the following description, when the accelerator is turned off while motor lock control is being performed, the motor lock control is canceled and the electric motor 3 is drive-controlled so that the vehicle 1 moves backward at a constant speed. Controlling the electric motor 3 so that the vehicle 1 moves backward at a constant speed is called constant speed control.

On the other hand, if the electric motor 3 is in a motor lock state on a flat road or on a downhill slope, it is considered that the wheels of the vehicle are caught on a protrusion such as a curb. Therefore, the motor lock control unit 15 does not perform motor lock control when the electric motor 3 is in the motor lock state on a flat road or on a downhill slope. That is, while allowing the electric motor 3 to generate torque, the electric parking brake 4 is not operated.

Next, an example of the processing operation of the motor lock control device 2 will be described with reference to FIG. 3. Note that the processing operations of the motor lock control device 2 described below are performed by the control section 10.

First, the control unit 10 determines whether the motor lock control flag is turned on (step S1). The motor lock control flag is a flag for prohibiting the electric motor 3 from generating torque, and the motor lock control flag is ON while the motor lock control is being performed. Therefore, when the motor lock control flag is ON, generation of torque by the electric motor 3 is prohibited, and when the motor lock control flag is OFF, generation of torque by the electric motor 3 is permitted.

If the motor lock control flag is not ON (step S1: NO), the control unit 10 determines that the torque _Tm generated in the electric motor 3 is larger than the allowable torque _Tlock , which is larger than 0, and It is determined whether the rotational speed ω _m of the electric motor 3 is approximately 0 (step S2). The allowable torque T _lock is the torque allowed for the electric motor 3 when the electric motor 3 is in the motor lock state. The allowable torque for the electric motor 3 is a torque that causes the electric motor 3 to be in a load state that does not cause it to fail. When the rotational speed ω _m of the electric motor 3 is approximately 0, it means that the electric motor 3 is not rotating or is hardly rotating.

If the torque T _m generated in the electric motor 3 is less than or equal to the allowable torque T _lock or if the rotational speed ω _m of the electric motor 3 is not approximately 0 (step S2: NO), the control unit 10 controls the driver's requested torque T _drv . It is determined whether or not it is 0 (step S3). When the required torque T _drv is 0, it means that the driver is not depressing the accelerator and the accelerator opening is 0.

If the required torque T _drv is not 0 (step S3: NO), the control unit 10 once ends the process and performs the process again from step S1. When the required torque T _drv is 0 (step S3: YES), the control unit 10 cancels the constant speed control (step S4), and causes the electric motor 3 to have a torque T _m corresponding to the driver's required torque T _drv . The electric motor 3 is drive-controlled so that this occurs (step S5). The constant speed control is a control that drives the electric motor 3 so that the vehicle 1 moves backward at a constant speed, and is performed in step S16, which will be described later. Therefore, if the previously performed constant speed control in step S16 is still being performed, the constant speed control is canceled in step S4. On the other hand, if the constant speed control in step S16 is not performed, there is no need to do anything in particular in step S4. Then, the control unit 10 once ends the process and performs the process again from step S1.

On the other hand, in step S2 described above, if the torque T _m generated in the electric motor 3 is larger than the allowable torque T _lock and the rotational speed ω _m of the electric motor 3 is approximately 0 (step S2: YES), the control unit 10 determines whether the gradient angle Grad of the road surface on which the vehicle 1 makes contact is larger than 0°, that is, whether the road surface on which the vehicle 1 makes contact with the ground is an uphill slope road (step S6).

When the gradient angle Grad of the road surface of the vehicle 1 is 0° or less, that is, the road surface of the vehicle 1 is a flat road or a downhill slope (step S6: NO), the control unit 10 sets the electric motor 3 to an allowable torque T. The electric motor 3 is drive-controlled so that a torque T _m corresponding to _{the lock} is generated (step S7).

If the gradient angle Grad of the road surface on which the vehicle 1 makes contact is larger than 0°, that is, the road surface on which the vehicle 1 makes contact with the ground is an uphill slope road (step S6: YES), the control unit 10 turns on the motor lock control flag to turn on the electric motor. The generation of torque by the motor 3 is prohibited (step S8), and the electric parking brake 4 is activated (step S9). Then, the control unit 10 once ends the process and performs the process again from step S1.

On the other hand, in step S1 described above, if the motor lock control flag is ON (step S1: YES), the control unit 10 determines whether the driver's requested torque T _drv is larger than the running resistance torque T _res . Determination is made (step S10). The running resistance torque T _res may be obtained periodically or at an arbitrary timing, or may be obtained when performing step S10. When the running resistance torque T _res is determined periodically or at an arbitrary timing, the most recently determined running resistance torque T _res is used in step S10.

If the driver's requested torque T _drv is larger than the running resistance torque T _res (step S10: YES), the control unit 10 releases the operation of the electric parking brake 4 (step S11) and turns off the motor lock control flag. , the electric motor 3 is drive-controlled so that the electric motor 3 generates a torque _Tm corresponding to the driver's requested torque _Tdrv (step S12). Then, the control unit 10 once ends the process and performs the process again from step S1.

When the driver's requested torque T _drv is less than or equal to the running resistance torque T _res (step S10: NO), the control unit 10 determines whether the driver's requested torque T _drv is 0, that is, whether the driver has turned off the accelerator. (Step S13).

If the driver's requested torque T _drv is not 0, that is, if the driver has not released the accelerator (step S13: NO), the control unit 10 once ends the process and performs the process again from step S1. On the other hand, if the driver's requested torque T _drv is 0, that is, if the driver turns off the accelerator (step S13: YES), the control unit 10 turns off the motor lock control flag and stops the electric motor 3 from generating torque. permission is granted (step S14), and the operation of the electric parking brake 4 is released (step S15). Then, the control unit 10 performs constant speed control to drive and control the electric motor 3 so that the vehicle 1 moves backward at a constant speed (step S16). In the constant speed control in step S16, the backward speed of the vehicle 1 may be controlled, for example, by also controlling the drive of a braking device (not shown) of the vehicle 1. Then, the control unit 10 once ends the process and performs the process again from step S1.

Next, an example of a time chart of motor lock control will be described with reference to FIGS. 4 and 5.

In the example shown in FIG. 4, at time t1, when the electric motor 3 enters the motor lock state and motor lock control is performed, the generation of torque of the electric motor 3 is prohibited, so that the torque generated by the electric motor 3 is 0, and the electric parking brake 4 is activated. Thereafter, at time t2, even if the driver turns on the accelerator, the state in which the electric motor 3 is prohibited from generating torque is maintained until the driver's requested torque T _drv becomes larger than the running resistance torque T _res . , the electric parking brake 4 remains activated. Thereafter, at time t3, when the driver's requested torque T _drv becomes larger than the running resistance torque T _res , the motor lock control is released, torque is generated from the electric motor 3, and the electric parking brake 4 is released. .

In the example shown in FIG. 5, at time t4, when the electric motor 3 enters the motor lock state and motor lock control is performed, the generation of torque of the electric motor 3 is prohibited, so that the torque generated by the electric motor 3 is 0, and the electric parking brake 4 is activated. Thereafter, at time t5, when the accelerator is turned off, the motor lock control is released, torque is generated in the electric motor 3 so that the vehicle 1 moves backward at a constant speed, and the electric parking brake 4 is released.

As described above, in the motor lock control device 2 according to the present embodiment, when the electric motor 3 enters the motor lock state on an uphill road, the motor lock prevents the electric motor 3 from generating torque and activates the electric parking brake 4. Since the control is performed, failure of the electric motor 3 can be suppressed. Here, when the driver wants to slide down the motor-locked vehicle 1 on an uphill road, the driver consciously or unconsciously turns off the accelerator. Therefore, this motor lock control device 2 releases the motor lock control when the accelerator is turned off while the motor lock control is being performed. In this way, the motor lock control can be released by an operation performed consciously or unconsciously by the driver when the driver wants to lower the vehicle 1, so the motor lock control can be easily released.

Furthermore, in this motor lock control device 2, when the accelerator is turned off while the motor lock control is being performed on an uphill road, the motor lock control is canceled and the electric motor is activated so that the vehicle 1 moves backward at a constant speed. to drive and control. Thereby, it is possible to suppress the downward sliding speed of the vehicle 1 from becoming excessive, such as when the inclination angle of the slope road is large.

A possible case where the motor locks up on a flat road or a downhill road is when the wheels of the vehicle 1 are caught on a protrusion such as a curb. In such a case, the driver is considered to be intending to move the vehicle 1 forward, unlike when the motor is locked on an uphill road. Therefore, this motor lock control device does not perform motor lock control when the motor is locked on a flat road or on a downhill slope. Thereby, the electric motor 3 can be driven according to the driver's intention.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be modified or applied to other things without changing the gist of each claim. It's okay.

DESCRIPTION OF SYMBOLS 1... Vehicle, 2... Motor lock control device, 3... Electric motor, 4... Electric parking brake, 10... Control part, 11... Vehicle information acquisition part, 12... Road surface slope acquisition part, 13... Electric motor control part, 14... Electric parking brake control section, 15...Motor lock control section.

Claims (3)

A control unit that performs motor lock control that prohibits generation of torque of the electric motor and operates an electric parking brake of the vehicle when an electric motor that is a drive source of the vehicle enters a motor lock state on an uphill slope road. Prepare,
The control unit releases the motor lock control when the accelerator is turned off while the motor lock control is being performed.
Motor lock control device. When the accelerator is turned off while the motor lock control is being performed, the control unit releases the motor lock control and controls the electric motor so that the vehicle moves backward at a constant speed.
The motor lock control device according to claim 1. The control unit does not perform the motor lock control when the electric motor is in a motor lock state on a flat road or a downhill slope.
The motor lock control device according to claim 1 or 2.

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