Vehicle control device

Abstract

To provide a control device of a vehicle capable of escaping from a stall state while suppressing the frequency of increasing / decreasing motor torque.SOLUTION: A control device 10 of a vehicle Ve including a motor 1 as a drive source includes a stall determination unit 11 that determines a stall state in which the motor 1 is not rotating in a state where torque of the motor 1 is generated based on a drive instruction, and a torque control unit 12 that performs torque control for controlling the torque so that a rotation angle of the motor 1 changes when it is determined that the motor 1 is in the stall state, and the torque control unit 12 performs the torque control at a predetermined frequency based on a temperature of the motor 1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] In recent years, efforts to realize a low-carbon or carbon-free society have become more active, and research and development into electrification technologies is being conducted in order to reduce CO2 emissions and improve energy efficiency in vehicles.

[0003] For example, in a vehicle equipped with a motor as a drive source, when the vehicle is stopped on an uphill road or when a motor torque is output that is sufficient to prevent the vehicle from rolling downhill, there are known means for preventing the motor from entering a stall state in which the motor rotation is almost stopped despite the motor torque being applied, or a motor lock state in which the motor output drops suddenly due to current continuing to flow through a specific phase.

[0004] Patent Document 1 describes a control that, when it is determined that there is a possibility of motor lock, increases or decreases the motor torque to impart vibrations to the vehicle, thereby informing the user of the possibility of motor lock. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4725419 Summary of the Invention [Problem to be solved by the invention]

[0006] Executing control to increase or decrease motor torque and causing vibration to the vehicle results in vehicle behavior that is unintended by the user, so it is preferable to reduce the frequency of such control.In conventional technology, control to increase or decrease motor torque is executed using motor temperature as one parameter, but the specific temperature state of the motor is not taken into consideration, and even when the motor temperature is relatively low, for example, control to increase or decrease motor torque is executed and causes vibration to the vehicle, which may increase the frequency of increasing or decreasing motor torque.

[0007] The present invention provides a vehicle control device that can escape from a stall state while suppressing the frequency of increasing or decreasing motor torque in the stall state. [Means for solving the problem]

[0008] One aspect of the present invention is A control device for a vehicle equipped with a motor as a drive source, a stall determination unit that determines a stall state in which the motor is not rotating while torque is being generated by the motor based on a drive command; a torque control unit that performs torque control to control the torque so that the rotation angle of the motor changes when it is determined that the stall state is occurring, The torque control unit The torque control is performed at a predetermined frequency based on the temperature of the motor. [Effects of the Invention]

[0009] According to the present invention, it is possible to escape from a stall state while suppressing the frequency with which the motor torque is increased or decreased in the stall state. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle Ve. [Figure 2] FIG. 2 is a block diagram showing an example of the control device 10. As shown in FIG. [Figure 3] FIG. 3 is a time chart showing an example of changes in each parameter when a control example in the embodiment is executed. [Figure 4] FIG. 4 is a diagram for explaining an example in which the motor rotation speed is overshot in torque recovery control. [Figure 5] FIG. 5 is a diagram for explaining the various regions in which a change of pedal pressure from the accelerator pedal to the brake pedal is expected. [Figure 6] FIG. 6 is a time chart showing an example of changes in each parameter when the brake pedal is operated while the torque reduction control is being executed. [Figure 7] FIG. 7 is a time chart showing an example of changes in each parameter when the brake pedal is operated while the torque recovery control is being executed. [Figure 8] FIG. 8 is a time chart showing an example of changes in each parameter when the brake pedal is operated while the torque balance control is being executed. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment will be described below with reference to the drawings. The following embodiment does not limit the present invention, and not all of the elements described in the following embodiment are necessarily essential to the present invention. Furthermore, two or more elements described in the following embodiment may be arbitrarily combined without departing from the spirit of the present invention. Note that, below, identical or similar elements are denoted by the same or similar reference numerals, and their description may be omitted or simplified.

[0012] The control device 10 in the embodiment is mounted on a vehicle Ve, and the control device 10 mainly controls the torque of a motor 1, which is a drive source.

[0013] [vehicle] First, the configuration of a vehicle Ve that is the subject of the embodiment will be described. The vehicle Ve may be any vehicle Ve equipped with a motor 1 as a drive source. Therefore, the vehicle Ve may be, for example, an electric vehicle equipped with only the motor 1 as a drive source, or a hybrid vehicle equipped with an engine and the motor 1 as a drive source. The drive type may be a two-wheel drive vehicle in which either the front or rear two wheels are drive wheels, a four-wheel drive vehicle in which the front and rear four wheels are drive power sources, or an all-wheel drive vehicle in which all wheels are drive wheels. In the embodiment, as shown in FIG. 1, a front-wheel drive electric vehicle is shown as an example.

[0014] The vehicle Ve includes, as its main components, a motor 1, a battery 2, a power conversion device 3, a braking device 4, various sensors 5, and a control device 10 that controls the vehicle Ve. In Fig. 1, thick solid lines indicate mechanical connections, dashed lines indicate electrical wiring, and thin solid arrows indicate the transmission and reception of control signals or detection signals.

[0015] The motor 1 is a motor generator used as a drive source, and is configured, for example, by a three-phase AC motor. The motor 1 is electrically connected to a battery 2 via a power conversion device 3. Electric power from the battery 2 can be supplied to the motor 1. When supplied with electric power, the motor 1 operates as an electric motor and outputs power for propelling the vehicle Ve. The motor 1 is also connected to front wheels 7, which are drive wheels, via a gear mechanism 6 with a speed change function, and the power output by the motor 1 is transmitted to the front wheels 7. In other words, the vehicle Ve can propel itself using the power output by the motor 1 by supplying electric power from the battery 2 to the motor 1. Note that the reference numeral 8 in FIG. 1 indicates the rear wheels.

[0016] Furthermore, when braking the vehicle Ve, the motor 1 is rotated by the front wheels 7, which are the driving wheels, and functions as a generator, performing so-called regenerative power generation. The electric power generated by the regenerative operation of the motor 1 is supplied to the battery 2, for example, via the power conversion device 3. This allows the battery 2 to be charged.

[0017] The power conversion device 3 is a so-called "power control unit" that converts input power and outputs the converted power, and is connected to the motor 1 and the battery 2. The power conversion device 3 includes an inverter 3a and a voltage control device 3b. The inverter 3a and the voltage control device 3b are electrically connected to each other.

[0018] The voltage control device 3b converts the input voltage and outputs the converted voltage. For example, a DC / DC converter or the like can be used as the voltage control device 3b. For example, when power from the battery 2 is supplied to the motor 1, the voltage control device 3b boosts the output voltage of the battery 2 and outputs it to the inverter 3a. Furthermore, for example, when regenerative power generation is performed by the motor 1, the voltage control device 3b reduces the output voltage of the motor 1 received via the inverter 3a and outputs it to the battery 2.

[0019] When supplying power from the battery 2 to the motor 1, the inverter 3a converts the power of the battery 2 received via the voltage control device 3b from direct current to alternating current and outputs the power to the motor 1. When regenerative power is generated by the motor 1, the inverter 3a converts the power received from the motor 1 from alternating current to direct current and outputs the power to the voltage control device 3b.

[0020] The battery 2 is a chargeable and dischargeable secondary battery, and has a plurality of storage cells connected in series or series-parallel. The battery 2 is configured to be able to output a high voltage of, for example, 100 to 400 V. The storage cells of the battery 2 can be lithium-ion batteries, nickel-metal hydride batteries, or the like.

[0021] The brake device 4 is a brake device that applies a braking force to the vehicle Ve, and may have various conventionally known configurations. For example, the brake device 4 is configured as an electric servo brake device including a brake caliper, a cylinder that transmits hydraulic pressure to the brake caliper, and an electric motor that generates hydraulic pressure in the cylinder (none of which are shown). The electric servo brake brakes the vehicle Ve using hydraulic pressure controlled in response to the driver's operation of the brake pedal. The electric servo brake device controls the electric motor in response to the input amount of brake pedal operation, and outputs braking torque to each wheel in response to the braking operation. Note that the brake device 4 may also be an electronically controlled hydraulic brake device, etc.

[0022] The various sensors 5 include, for example, an accelerator position sensor that detects the amount of operation of an accelerator pedal of the vehicle Ve, a brake position sensor that detects the amount of operation of a brake pedal of the vehicle Ve, a rotation speed sensor or resolver that detects the rotation speed of the motor 1, a temperature sensor that detects the temperature of the motor 1, a current sensor that detects the current in the windings of the motor 1, a vehicle speed sensor that detects the vehicle speed, which is the traveling speed of the vehicle Ve. The detection results by the various sensors 5 are transmitted to the control device 10 as detection signals.

[0023] The control device 10 is a computer that has, for example, a processor that performs various calculations, a storage unit that has a non-transitory storage medium that stores various information such as predetermined maps and programs, an input / output unit that controls input and output of data between the inside and outside of the control device 10, and the like (all of which are not shown), and that performs overall control of the vehicle Ve. For example, the control device 10 is realized by one ECU (Electronic Control Unit) or by multiple ECUs working together.

[0024] For example, the control device 10 is provided so as to be able to communicate with the power conversion device 3, the brake device 4, and various sensors 5. The control device 10 controls the power conversion device 3 to control the output of the motor 1, thereby controlling the driving force of the vehicle Ve. The control device 10 also controls the motor 1 and the brake device 4 to control the braking force of the vehicle Ve.

[0025] The control device 10 executes various programs stored in, for example, a storage unit. Conventionally, in electric vehicles and the like, a control method is known in which the vehicle Ve is stopped on an uphill road, for example, or the vehicle Ve is maintained in a stopped state by outputting a motor torque sufficient to prevent the vehicle Ve from sliding down. If such a stopped state continues, the vehicle enters a stall state (hereinafter also referred to simply as a "stall state") in which the rotation of the motor 1 is almost stopped despite the motor torque being output. If the vehicle enters a stall state, the motor torque is increased or decreased to attempt to escape from the stall state, and the increase or decrease in the motor torque causes the vehicle Ve to vibrate, thereby making the user aware of the stall state.

[0026] However, since control that causes vibrations in the vehicle Ve by increasing or decreasing the motor torque is a behavior of the vehicle Ve that is not intended by the user, it is preferable to reduce the frequency of such control. Therefore, in this embodiment, a predetermined program is executed to escape from a stall state while suppressing the execution of control that increases or decreases the motor torque.

[0027] Specifically, as an example of a program recorded in the memory unit, the control device 10 executes a torque control processing program that determines the frequency of control to increase or decrease the motor torque depending on the temperature of the motor 1, and performs torque control (hereinafter simply referred to as "torque control") to increase or decrease the motor torque depending on the frequency.

[0028] 2, the control device 10 includes, as functional units realized by executing the program, a stall determination unit 11, a torque control unit 12, and a notification control unit 13. In the following, the processes described as being performed by the stall determination unit 11, the torque control unit 12, and the notification control unit 13 are processes realized by the control device 10.

[0029] The control device 10 is configured to receive detection values ​​from the various sensors 5 described above, and to output processed calculation results to, for example, a predetermined display unit 9. The specific contents will be described later.

[0030] The stall determination unit 11 determines a stall state in which the motor 1 is not rotating while generating motor torque based on a drive command. For example, the stall determination unit 11 acquires the motor torque based on a current value detected by a current sensor. The stall determination unit 11 also acquires the motor rotation speed detected by a rotation speed sensor. Based on the acquired motor torque and motor rotation speed, for example, if the motor rotation speed is "0" or nearly "0" even though the motor torque is a predetermined torque, the stall determination unit 11 determines that the motor is in a stall state.

[0031] When the stall determination unit 11 determines that the motor 1 is in a stall state, the torque control unit 12 performs torque control to control the motor torque so as to change the rotation angle of the motor 1. That is, since the torque control unit 12 has determined that the motor 1 is in a stall state, it performs torque control by increasing or decreasing the motor torque so as to change the rotation angle of the motor 1 in order to get the motor out of the stall state.

[0032] Here, specific control content of the "torque control" will be described. The torque control in the embodiment includes torque reduction control (hereinafter simply referred to as "torque reduction control") that reduces motor torque so that the vehicle Ve moves backward, and torque return control (hereinafter simply referred to as "torque return control") that increases the motor torque by an amount reduced by the torque reduction control to restore the motor torque to the level before the torque reduction control was executed. In the embodiment, if it is determined that the vehicle Ve is in a stall state, the torque return control is executed immediately after the torque reduction control is executed. In this case, the behavior of the vehicle Ve is that the torque reduction control causes the vehicle Ve to slide down from the stopped position, and the torque return control causes the vehicle Ve to return to the stopped position or a position substantially the same as the stopped position. In other words, the torque control causes the vehicle Ve to move forward and backward. This forward and backward movement of the vehicle Ve causes the vehicle Ve to vibrate.

[0033] It is preferable that the rate of change of the motor torque in the torque reduction control is smaller than the rate of change of the motor torque in the torque return control. As described above, the torque reduction control reverses the vehicle Ve, and therefore reduces the discomfort felt by the user due to the vehicle Ve moving backward. In other words, the rate of change of the motor torque in the torque return control is set relatively larger than that in the torque reduction control. The torque return control is a control for returning the vehicle Ve to its original position from which it was stopped, and therefore, returning the reversed vehicle Ve to its original position more quickly may reduce the discomfort felt by the user.

[0034] Furthermore, it is preferable that torque control unit 12 controls the increase rate of motor torque so that the rotation angle of motor 1 changes in the forward direction of vehicle Ve at the end of torque return control. This is to prevent vehicle Ve from sliding down due to the inertia of vehicle Ve during torque return control. In other words, torque control unit 12 determines the increase rate of motor torque so as to overshoot the motor rotation speed in the positive direction.

[0035] Furthermore, the torque control unit 12 performs this torque control at a predetermined frequency, rather than continuously performing it until the user notices that the vehicle is in a stalled state, as is the case with conventionally known control, because continuous torque control increases the amount of slippage of the vehicle Ve.

[0036] As an example, torque control unit 12 performs torque control at a predetermined frequency based on the temperature of motor 1. Specifically, torque control unit 12 increases the frequency of torque control as the temperature of motor 1 increases. In other words, when the temperature of motor 1 is relatively low, torque control unit 12 decreases the frequency of torque control. The temperature of motor 1 refers to, for example, the temperature of the windings of motor 1.

[0037] More specifically, the torque control unit 12 records the temperature of the motor 1 when it is determined that the motor is in the stall state as an initial temperature Th0, and performs torque control when the temperature of the motor 1 rises and reaches a threshold value Th1 (Th1>Th0). If the torque control does not result in a predetermined operation, such as depressing the brake pedal, to escape from the stall state, the torque control unit 12 performs torque control again when the temperature of the motor 1 reaches a threshold value Th2 (Th2>Th1). Furthermore, if the predetermined operation, such as depressing the brake pedal, to escape from the stall state is not performed even in this state, the torque control unit 12 performs torque control again when the temperature of the motor 1 reaches a threshold value Th3 (Th3>Th2). The torque control unit 12 performs this torque control until the temperature of the motor 1 reaches a predetermined upper limit temperature or until a predetermined operation, such as depressing the brake pedal, to escape from the stall state is performed.

[0038] Furthermore, the torque control unit 12 reduces the temperature width of each threshold value Th of the temperature of the motor 1 so that torque control is performed more frequently as the temperature of the motor 1 increases. In other words, the temperature width from threshold value Th1 to threshold value Th2 is smaller than the temperature width from initial temperature Th0 to threshold value Th1 compared to the temperature width from threshold value Th1 to threshold value Th2. In other words, the temperature increase width is smaller in the temperature width from threshold value Th1 to threshold value Th2. Furthermore, the temperature width from threshold value Th2 to threshold value Th3 is smaller than the temperature width from threshold value Th1 to threshold value Th2 compared to the temperature width from threshold value Th2 to threshold value Th3. In this way, the torque control unit 12 reduces the temperature width of the threshold value Th of the temperature of the motor 1 at which torque control is performed as the temperature of the motor 1 increases, thereby increasing the frequency of torque control. More detailed control content will be described using a time chart described later.

[0039] Torque control may be performed after the stall determination unit 11 determines that the motor is in a stall state, i.e., when the temperature of the motor 1 is at the initial temperature Th0. However, in this embodiment, in order to reduce the frequency of torque control, the torque control is performed when the temperature of the motor 1 reaches a threshold value Th1 after the stall state is determined, for example.

[0040] Furthermore, the predetermined operation for escaping the stall state described above includes not only the operation of the brake pedal but also an operation for releasing the state in which the vehicle Ve is kept stopped by the motor torque, such as further depression of the accelerator pedal. In the following description, the predetermined operation for escaping the stall state will be described as "the operation of the brake pedal." When this predetermined operation is performed, the torque control unit 12 ends the torque control.

[0041] In this way, operating the brake pedal can escape the stall state. However, when the user switches from operating the accelerator pedal to operating the brake pedal, an unavoidable time is required for the user to change pedal operation. During this time, neither the accelerator pedal nor the brake pedal is operated, meaning that the motor torque corresponds to the accelerator pedal position. This can cause the vehicle Ve to significantly roll back. Therefore, in this embodiment, a control is executed to suppress the vehicle Ve from rolling back when the user switches from operating the accelerator pedal to the brake pedal.

[0042] Specifically, when the accelerator pedal is switched to the brake pedal, the torque control unit 12 controls the motor torque at a rate of change that is smaller than the rate of change of torque corresponding to the required driving force. In other words, while the motor torque would normally decrease at the rate of change that occurs when the accelerator is released, in this embodiment, the torque control unit 12 controls the motor torque so that it decreases more gradually than the rate of change that occurs when the accelerator is released. This makes it possible to suppress the amount of rolling of the vehicle Ve.

[0043] On the other hand, the timing at which the brake pedal is depressed is not uniquely determined by the user's operation. For example, even if the brake pedal is depressed while torque control is being executed, the brake pedal may be depressed while torque reduction control is being executed, or the brake pedal may be depressed while torque return control is being executed. Since the torque reduction control and the torque return control are different controls, it is preferable to execute torque control according to each control, even when the drive command is switched from the accelerator pedal to the brake pedal when the accelerator pedal is operated to the brake pedal when torque reduction control is being executed. Therefore, in this embodiment, different controls are executed when there is a change of pedal pressure from the accelerator pedal to the brake pedal while torque reduction control is being executed and when there is a change of pedal pressure from the accelerator pedal to the brake pedal while torque return control is being executed.

[0044] If the driver shifts to the brake pedal while the torque reduction control is being executed, the torque control unit 12 maintains the motor torque reduction rate at least when the accelerator pedal is depressed. This is because controlling the motor torque at a higher reduction rate would cause the vehicle Ve to roll further. Since the vehicle Ve is backing up while the torque reduction control is being executed, it is preferable to control the motor torque at a lower rate of change to minimize the amount of roll of the vehicle Ve. Therefore, the torque control unit 12 reduces the motor torque at a rate of change smaller than the motor torque reduction rate when the accelerator pedal is depressed. Even if the motor torque reduction rate is reduced in this way, the vehicle Ve is backing up, so the motor 1 is rotating and the effect on the temperature rise of the motor 1 is relatively small. More detailed control details will be described later with reference to the time chart.

[0045] On the other hand, if a change of foot pressure to the brake pedal occurs while the torque return control is being executed, the torque control unit 12 continues the torque return control until the torque that was reduced by the torque reduction control is increased, and then reduces the motor torque. That is, the torque control unit 12 restores the motor torque to a balanced torque that brings the vehicle Ve into a stopped state, and then reduces the motor torque from that state. As described above, the torque return control is expected to last for a very short time because the rate of change of torque is larger than, for example, the torque reduction control. Therefore, it is expected that the user will feel little discomfort even if the motor torque is restored to a balanced torque.

[0046] Then, when the motor torque returns to the balance torque, torque control unit 12 reduces the motor torque at a rate that is, for example, at least smaller than the rate of change of motor torque in response to accelerator OFF due to the disappearance of the required driving force, but larger than the rate of change in torque reduction control. This is because it is possible to prevent the user from having an illusion that the torque reduction control is continuing. Also, a rate of change that is larger than the rate of change in torque reduction control is preferable in order to provide a thermal margin.

[0047] Furthermore, the timing at which the brake pedal is depressed by the user may occur during the torque reduction control or torque recovery control, or after the torque recovery control has ended, while the vehicle Ve is maintained in a stopped state while generating motor torque based on a drive command. In the following description, the control during which the vehicle Ve is maintained in a stopped state while generating motor torque based on a drive command after the torque recovery control has ended is referred to as "torque balance control." Even during the torque balance control, it is preferable to control the motor torque to prevent the vehicle Ve from rolling backward when the accelerator pedal is switched to the brake pedal. Therefore, in this embodiment, if the required driving force disappears due to a change in the drive command during the balance control, the torque control unit 12 reduces the motor torque at a rate that is smaller than the rate of change of the motor torque corresponding to the accelerator being released. The rate of reduction of the motor torque at this time may be different from the rate of reduction in the torque reduction control described above and may be the same as the rate of reduction of the motor torque when the accelerator pedal is switched to the brake pedal during the torque recovery control, for example. This makes it possible to give the user the illusion that torque reduction control is continuing, and further makes it possible to provide a thermal margin.

[0048] The notification control unit 13 notifies the user that the motor 1 is in a stall state. That is, when the stall determination unit 11 determines that the motor 1 is in a stall state, a warning notification indicating the stall state is issued on a predetermined display unit 9, such as an instrument panel or a navigation system. Alternatively, the warning notification of the stall state may be issued to the user by generating a predetermined warning sound. In addition, in the embodiment, once a stall state is determined and a notification is issued, the warning notification is continued until the stall state is resolved. That is, by continuing to issue a warning notification until the brake pedal or accelerator pedal is further depressed, the user is made aware of the stall state more quickly and is prompted to perform a predetermined operation such as pressing the brake pedal.

[0049] [Time chart] Next, an example of torque control processing executed by the control device 10 will be described using a time chart. FIG. 3 is a time chart showing an example of this processing, and this processing is executed, for example, when the vehicle Ve stalls while maintaining a stopped state by outputting motor torque on an uphill road. In the example shown in FIG. 3, the accelerator pedal, brake pedal, warning notification, stall protection flag, stall determination flag, motor temperature, motor torque, and motor rotation speed are shown, with changes in these parameters being plotted on the vertical axis. The horizontal axis represents time. The stall protection flag is a flag for determining that a stall state has occurred and starting the above-mentioned torque control, and torque control is executed when the stall protection flag is ON.

[0050] Specifically, first, until time t1, the user operates the accelerator pedal on an uphill road to output a predetermined motor torque, thereby maintaining the vehicle Ve in a stopped state. Therefore, from time t0 to time t1, the motor torque and motor rotation speed are constant. Also, the temperature of the motor 1 is at a predetermined temperature that is relatively low compared to the upper limit temperature at which torque is limited (hereinafter simply referred to as the "upper limit temperature"). Note that the other parameters, namely the brake pedal, warning display, stall protection flag, and stall determination flag, are all OFF.

[0051] Then, at time t1, the motor torque increases. This can occur, for example, when the vehicle Ve slides slightly backward despite the constant output of a predetermined motor torque, and the user further depresses the accelerator pedal to maintain the vehicle stationary state. Meanwhile, while the motor torque is increasing, the motor rotation speed begins to decrease.

[0052] Next, at time t2, the motor rotation speed becomes "0" or nearly "0", and the stall determination flag is turned ON by the stall determination unit 11. The temperature of the motor 1 when this stall determination flag is turned ON, i.e., when it is determined that the motor is in a stall state, is set to the initial temperature Th0.

[0053] At time t2, it is determined that the vehicle is in a stall state, but the stall protection flag remains OFF. This is because, although the vehicle is in a stall state, the temperature of the motor 1 is relatively low, for example, compared to the upper limit temperature, and therefore turning ON the stall protection flag prevents excessive torque control from being executed. In other words, this is to prevent the vehicle Ve from behaving in a manner that is unintended by the user, such as moving forward or backward, due to the execution of torque control.

[0054] At time t2, the motor 1 is not rotating, and the temperature of the motor 1 begins to rise due to, for example, a current continuing to flow through a specific phase.

[0055] Next, at time t3, the temperature of the motor 1, which began to rise at time t2, reaches threshold value Th1. In response to this, the stall determination unit 11 turns on the stall protection flag. Then, with the stall protection flag turned on, the torque control unit 12 performs the torque control described above.

[0056] Specifically, torque control unit 12 performs torque reduction control and torque return control from time t3 to time t4. At this time, torque control unit 12 reduces the amount of slippage of vehicle Ve during torque reduction control by making the torque change rate in torque return control larger than the torque change rate in torque reduction control. Furthermore, torque control unit 12 controls the motor torque increase rate so that the rotation angle of motor 1 changes in the forward direction of vehicle Ve at the end of torque return control. Figure 4 shows an enlarged view of the period from time t3 to time t4 enclosed by the dashed dotted line in Figure 3. As shown in Figure 4, torque control unit 12 determines the motor torque increase rate so that the motor rotation speed overshoots in the positive direction at the end of torque return control.

[0057] In addition, as torque reduction control and torque recovery control are performed, the vehicle Ve moves forward and backward, and the motor rotation speed changes accordingly, i.e., the rotation angle of the motor 1 changes, so the stall determination flag is turned OFF.

[0058] Furthermore, at time t3, the stall protection flag is turned ON, and thus the notification control unit 13 issues a warning notification. As described above, the warning notification may be issued by any appropriate method, such as displaying a warning on the predetermined display unit 9 or emitting a warning sound. In the example shown in FIG. 3, this warning notification remains ON until the brake pedal is operated. That is, in the example of FIG. 3, while the torque reduction control and the torque recovery control are being executed, the stall determination flag is turned OFF, but the drive command has not changed from the accelerator pedal to the brake pedal, and it is highly likely that the user is unaware that the vehicle is in a stall state or is close to a stall state, so the warning notification continues to be issued.

[0059] The temperature of the motor 1 from time t3 to time t4 increases slowly or remains almost unchanged because the motor 1 is rotated by the torque reduction control and the torque recovery control.

[0060] Next, at time t4, the torque reduction control and torque recovery control end, and the stall protection flag is turned OFF. Meanwhile, as a result of the execution of the torque control described above, the vehicle Ve moves forward and backward, and the vehicle Ve vibrates, but at time t4, the brake pedal is not being operated. In other words, it is highly likely that the user is unaware of the stall state. Then, the motor rotation speed is again "0", and the temperature of the motor 1 is also above the threshold value Th1. Therefore, at time t4, the stall determination flag is turned ON again.

[0061] It should be noted that, as in conventionally known control, if the stall protection flag is turned ON, it is conceivable that torque reduction control and torque restoration control will continue to be executed until the user notices that the vehicle is in a stalled state. However, if such torque control is continued, the amount of slippage of the vehicle Ve will continue to increase. Therefore, in this embodiment, torque control is configured to be performed at a predetermined frequency.

[0062] Then, as the motor enters a stall state again, the temperature of the motor 1 rises further. As the temperature of the motor 1 continues to rise, it reaches threshold value Th2 (time t5). When the temperature of the motor 1 reaches threshold value Th2, the stall protection flag is turned ON again, and torque reduction control and torque recovery control are executed. Then, as the torque reduction control and torque recovery control are executed, the motor rotation speed changes, and the stall determination flag is turned OFF (time t6).

[0063] As described above, in this embodiment, the higher the temperature of the motor 1, the more frequently the torque reduction control and torque recovery control are performed. Therefore, the time change from when the stall determination flag is turned ON until when the stall protection flag is turned ON is shorter from time t4 to time t5 than from time t2 to time t3. Also, the temperature change from when the stall determination flag is turned ON until when the stall protection flag is turned ON is smaller from time t4 to time t5 than from time t2 to time t3.

[0064] Next, at time t6, the torque reduction control and torque recovery control are completed, the stall protection flag is turned OFF again, and the motor rotation speed becomes "0", thereby turning the stall determination flag ON.

[0065] Note that the control executed after time t6 involves repeatedly executing torque reduction control and torque recovery control each time the temperature of the motor 1 reaches a predetermined threshold value (e.g., threshold value Th3, threshold value Th4, etc.). For example, the control from time t6 to time t8 is the same as the control from time t4 to time t6. Furthermore, for example, the control from time t8 to time t10 is the same as the control from time t4 to time t6. Therefore, a description of the control from time t6 to time t10 in the time chart of FIG. 3 will be omitted. Note that if, for example, the brake pedal is operated during this period, the torque control is terminated.

[0066] Furthermore, the interval between threshold values ​​Th becomes smaller as the temperature of the motor 1 increases. As the temperature of the motor 1 increases, the temperature of the motor 1 approaches the upper limit temperature, and so the frequency with which torque control is executed is increased to make the user aware that the motor is in a stalled state.

[0067] In the example of Fig. 3, at time t11, the accelerator pedal is released and the brake pedal is released. Therefore, at time t11, the stall determination flag, which was in the ON state, is turned off and the warning display is also turned off. In other words, at time t11, the drive command is changed from the accelerator pedal to the brake pedal, the vehicle is released from the stall state, and the torque control that has been performed at a predetermined frequency is terminated.

[0068] At this time t11, the brake pedal is operated, so that the motor torque is reduced as quickly as possible.

[0069] Next, a control example for suppressing the vehicle Ve from rolling downhill when the accelerator pedal is changed to the brake pedal will be described.

[0070] FIG. 5 is an enlarged view illustrating the timing at which a changeover from the accelerator pedal to the brake pedal may occur. The area indicated by "a" indicates the area in which torque reduction control is executed, the area indicated by "b" indicates the area in which torque restoration control is executed, and the area indicated by "c" indicates the area in which torque balancing control is executed. In other words, a changeover from the accelerator pedal to the brake pedal may occur when any of the torque controls is being executed. Note that the example shown in FIG. 5 illustrates the relationship between the timing of a changeover to the brake pedal and each of the torque controls, and therefore the vertical axis typically shows motor torque and motor rotation speed as parameters. Below, using FIGS. 6 to 8, we will explain how the motor torque, motor rotation speed, brake braking force, accelerator opening, and brake opening change when a changeover to the brake pedal is executed while each of the torque controls is being executed.

[0071] Fig. 6 shows an example of a case where a change of foot pressure to the brake pedal is performed during the execution of the torque reduction control shown in "a" in Fig. 5. Note that the solid line indicates the change in parameters in the embodiment, and the dashed line indicates the change in parameters in the conventional example.

[0072] At time t20, the execution of torque reduction control is started. That is, as explained in the time chart of Fig. 3, when the temperature of the motor 1 reaches a predetermined threshold value Th, the stall protection flag is turned ON and the torque reduction control is executed.

[0073] From this state, let us say that at time t21, the user changes their foot from the accelerator pedal to the brake pedal. Specifically, at time t21, the user releases their foot from the accelerator pedal, performing an accelerator-off action. Therefore, at time t21, the accelerator opening begins to decrease. Normally, as shown in the conventional example, the motor torque and motor rotation speed would rapidly decrease at a rate that corresponds to the decrease in accelerator opening as the accelerator-off action occurs.

[0074] However, if the motor torque or motor rotation speed suddenly decreases, the vehicle Ve, which has been gradually moving backward due to the torque reduction control, will suddenly slide downhill when the accelerator is released and the torque reduction control ends. Therefore, in this embodiment, to prevent such a slide, the motor torque is reduced at a predetermined reduction rate until the brake pedal is turned on and the braking force applied by the brake device 4 reaches a value that stops the vehicle Ve. In other words, the torque reduction control continues until the braking force reaches a value that stops the vehicle Ve. It is preferable that the reduction rate of the motor torque at this time be even smaller than the reduction rate up to time t21, for example. This is because the amount of slide of the vehicle Ve can be further reduced.

[0075] Next, at time t22, the brake pedal is depressed. As a result, the brake opening degree starts to increase, and the brake braking force also starts to increase. In the example shown in FIG. 6, the accelerator opening degree, which began to decrease at time t21, becomes OFF, i.e., "0," at time t22. Accordingly, the motor torque in the conventional example also becomes "0." On the other hand, in this embodiment, at time t22, the brake braking force has not increased to a value that maintains the vehicle Ve in a stopped state, so the motor torque is decreasing at a predetermined rate, and torque reduction control is continuously executed.

[0076] Next, at time t23, the braking force becomes sufficient to stop the vehicle Ve. Therefore, the control of the motor torque ends, and the motor torque decreases toward "0." Accordingly, the motor rotation speed also becomes "0."

[0077] In this way, if the driver switches to the brake pedal while torque reduction control is being executed, the torque reduction control is executed until the brake braking force reaches a value that maintains the vehicle Ve in a stopped state, thereby minimizing the amount of rolling of the vehicle Ve when the driver switches from the accelerator pedal to the brake pedal.

[0078] Fig. 7 shows an example of a case where a driver changes his / her foot to the brake pedal while the torque recovery control shown in "b" in Fig. 5 is being executed. Note that the solid line indicates the change in the parameter in the embodiment, and the dashed line indicates the change in the parameter in the conventional example.

[0079] From time t30 to time t31, torque reduction control is being executed, and at time t31, torque recovery control is started to be executed.

[0080] From this state, let us say that at time t32, the user changes their foot from the accelerator pedal to the brake pedal. Specifically, at time t32, the user releases their foot from the accelerator pedal, performing an accelerator-off action. Therefore, at time t32, the accelerator opening degree begins to decrease. Normally, as shown in the conventional example, the motor torque and motor rotation speed would rapidly decrease at a rate that corresponds to the decrease in accelerator opening degree in response to the accelerator-off action.

[0081] However, if the motor torque or motor rotation speed suddenly decreases, the vehicle Ve will suddenly roll downhill when the accelerator is released and the torque recovery control ends. Therefore, in this embodiment, at time t32, in order to prevent such a roll downhill, motor torque is output until the braking force of the brake device 4 reaches a value that stops the vehicle Ve. In other words, torque recovery control is continued until the braking force reaches a value that stops the vehicle Ve, i.e., a balanced torque. The rate of increase in motor torque at this time may be the same as the rate of increase in torque recovery control from time t31 to time t32, for example.

[0082] Next, at time t33, the motor torque reaches the balance torque. In the example shown in FIG. 7, the brake pedal is depressed at time t33. As a result, the brake opening degree begins to increase, and the brake braking force also begins to increase. In the example shown in FIG. 7, the accelerator opening degree, which began to decrease at time t32, becomes OFF at time t33, i.e., becomes "0." Accordingly, the motor torque in the conventional example also becomes "0." Note that the motor rotation speed at time t33 is a positive value due to the above-mentioned overshoot.

[0083] Then, from time t33, the motor torque begins to decrease. Normally, since the brake is ON and the accelerator pedal position is "0," the motor torque would decrease as quickly as possible. However, at time t33, the braking force has not yet increased to a value that would maintain the vehicle Ve in a stopped state. Therefore, in this embodiment, the torque control unit 12 reduces the motor torque at a rate that is smaller than the rate of change of the motor torque corresponding to the accelerator being OFF due to the absence of the required driving force, but is greater than the rate of reduction in the torque reduction control. This prevents the user from having the illusion that the torque reduction control is continuing. It also makes it possible to provide a thermal margin.

[0084] Next, at time t34, the braking force becomes sufficient to stop the vehicle Ve. Therefore, the control of the motor torque ends, and the motor torque decreases toward "0." Accordingly, the motor rotation speed also becomes "0."

[0085] In this way, if the driver switches to the brake pedal while torque recovery control is being executed, torque control is executed until the braking force reaches a value that maintains the vehicle Ve in a stopped state, thereby minimizing the amount of rolling of the vehicle Ve when the driver switches from the accelerator pedal to the brake pedal.

[0086] Fig. 8 shows an example of a case where a driver changes his / her foot to the brake pedal while executing the torque balancing control shown in "c" in Fig. 5. The solid line indicates the change in parameters in the embodiment, and the dashed line indicates the change in parameters in the conventional example.

[0087] From time t40 to time t41, the torque reduction control and the torque recovery control are being executed, and at time t41, the execution of the torque balancing control is started.

[0088] From this state, let us say that at time t42, the user changes their foot from the accelerator pedal to the brake pedal. Specifically, at time t42, the user releases their foot from the accelerator pedal, performing an accelerator-off action. Therefore, at time t42, the accelerator opening degree begins to decrease. Normally, as shown in the conventional example, the motor torque and motor rotation speed would rapidly decrease at a rate that corresponds to the decrease in accelerator opening degree in response to the accelerator-off action.

[0089] However, if the motor torque or motor rotation speed suddenly decreases, the vehicle Ve will suddenly slide downhill as the torque balancing control ends when the accelerator is released. Therefore, in this embodiment, in order to prevent such a slide, at time t42, the motor torque is reduced at a predetermined reduction rate until the braking force applied by the brake device 4 reaches a value that stops the vehicle Ve. The reduction rate of the motor torque at this time is, for example, smaller than the rate of change of the motor torque in response to the accelerator being released due to the absence of the required driving force, but greater than the reduction rate in the torque reduction control. This makes it possible to prevent the vehicle Ve from sliding downhill while the braking force increases to a value that maintains the vehicle stopped.

[0090] Next, at time t43, the brake pedal is depressed. As a result, the brake opening degree begins to increase, and the brake braking force also begins to increase. In the example shown in FIG. 8, the accelerator opening degree, which began to decrease at time t42, becomes OFF at time t43, i.e., becomes "0." Accordingly, the motor torque in the conventional example also becomes "0." Note that, at time t43, the brake braking force has not increased to a value that maintains the vehicle Ve in a stopped state, so the control to reduce the motor torque that began at time t42 continues to be executed, and therefore the motor torque is decreasing at a predetermined rate.

[0091] Next, at time t44, the braking force becomes sufficient to stop the vehicle Ve. Therefore, control of the motor torque ends, and the motor torque decreases toward "0." Accordingly, the motor rotation speed also becomes "0."

[0092] In this way, if the driver switches to the brake pedal while torque balancing control is being performed, torque control is performed until the braking force reaches a value that maintains the vehicle Ve in a stopped state, thereby minimizing the amount of rolling of the vehicle Ve when the driver switches from the accelerator pedal to the brake pedal.

[0093] As described above, in the embodiment, when it is determined that the vehicle is in a stall state, torque control is performed at a predetermined frequency. This torque control causes the vehicle Ve to slide down or move forward or backward due to the torque change, so it is possible to prompt the user to operate the brake pedal, etc., thereby avoiding the stall state.

[0094] Furthermore, since torque control is configured to be performed at a predetermined frequency based on the motor temperature, the amount of slippage of the vehicle Ve can be reduced, or the possibility that the user will feel uncomfortable due to the continuous execution of torque control can be reduced, compared to, for example, a case where torque control is performed continuously until the user notices that the vehicle is in a stall state. In other words, it is possible to escape from the stall state while suppressing the frequency of increasing or decreasing the motor torque.

[0095] Furthermore, in the embodiment, the frequency of torque control is increased as the temperature of the motor 1 increases. In other words, when the temperature of the motor 1 is relatively low, the frequency of torque control decreases. Therefore, for example, when the temperature of the motor 1 is high, the frequency of torque control increases, which increases the likelihood that the user will operate the brake pedal, thereby enabling the vehicle to escape from a stall state and preventing the temperature of the motor 1 from reaching the upper limit temperature at which torque is limited. On the other hand, when the temperature of the motor 1 is low, the frequency of torque control is relatively reduced, which reduces the risk of the vehicle Ve sliding downhill or moving forward and backward due to torque control, thereby reducing the discomfort, etc., that these behaviors of the vehicle Ve cause to the user.

[0096] In addition, in this embodiment, the torque control is terminated when the vehicle changes from a stalled state to a non-stalled state due to a change in a drive command, such as from an accelerator pedal operation to a brake pedal operation. Therefore, for example, if the torque control is terminated in a state where there is no such drive command, there is a possibility that the vehicle Ve will roll over. However, by terminating the torque control based on the drive command, it is possible to avoid or suppress the possibility of the vehicle Ve rolling over.

[0097] In addition, in the embodiment, the torque control includes torque reduction control and torque return control, and the torque reduction control and torque return control are configured to use different motor torque reduction rates when the accelerator pedal is switched to the brake pedal during execution of each control. That is, in normal control, if the accelerator pedal is switched to the brake pedal during torque control, the motor torque is adjusted according to the accelerator opening when the accelerator is released, causing the motor torque to suddenly decrease and causing the vehicle Ve to roll back. On the other hand, in the embodiment, the motor torque reduction rate is changed depending on the timing of the torque reduction control and the torque return control, thereby preventing the vehicle Ve from rolling back when the accelerator pedal is switched to the brake pedal. Furthermore, by executing motor torque control at different reduction rates, the possibility that the user will have the illusion that the torque reduction control is being executed while the torque return control is being executed, for example, is reduced.

[0098] Furthermore, in this embodiment, if there is a change of pedal pressure from the accelerator pedal to the brake pedal while the torque reduction control is being executed, the torque reduction rate corresponding to the decrease in the required driving force is set to be smaller than the torque reduction rate during the torque reduction control. That is, if the brake pedal is operated while the torque reduction control is being executed, the motor torque would normally be set to the motor torque corresponding to the accelerator being released, and this motor torque would decrease rapidly, causing the vehicle Ve to roll over. However, by setting the motor torque reduction rate to be smaller than the reduction rate during execution of the torque reduction control, in other words, by making this reduction rate gentler, it is possible to prevent the vehicle Ve from rolling over when the accelerator pedal is changed to the brake pedal.

[0099] In addition, in this embodiment, the motor torque increase rate is determined so that the motor rotation angle changes in the forward direction of the vehicle Ve when the torque return control ends. That is, when the torque return control ends, the motor rotation speed is caused to overshoot in the forward direction. This makes it possible to prevent the vehicle Ve from sliding downhill due to the inertia of the vehicle Ve during the torque return control, for example.

[0100] Furthermore, in this embodiment, if a pedal change from the accelerator pedal to the brake pedal occurs while the torque return control is being executed, the torque return control is continued until the motor torque is increased by the amount reduced by the torque reduction control. That is, the motor torque is increased until the motor torque returns to a balanced torque that maintains the vehicle Ve in a stopped state. This makes it possible to prevent the vehicle Ve from rolling back down when the pedal change from the accelerator pedal to the brake pedal is executed, compared to a case in which the torque return control is terminated before the balanced torque has been restored when the pedal change from the accelerator pedal to the brake pedal is executed.

[0101] In addition, in this embodiment, if a user shifts from the accelerator pedal to the brake pedal while torque balancing control is being executed to maintain the vehicle Ve in a stopped state after torque recovery control has ended, the motor torque is reduced at a rate that is smaller than the rate of change of motor torque corresponding to accelerator OFF and greater than the reduction rate in the torque reduction control. This reduces the risk of the vehicle Ve rolling back down when the user shifts from the accelerator pedal to the brake pedal while torque balancing control is being executed after torque recovery control has ended. Furthermore, controlling the motor torque at a reduction rate different from the reduction rate in the torque reduction control reduces the likelihood that the user will have an illusion that torque reduction control is being executed.

[0102] In addition, in the embodiment, the rate of change of the motor torque during the torque reduction control is configured to be smaller than the rate of change of the motor torque during the torque return control. In other words, the rate of change of the motor torque during the torque return control is relatively larger than the rate of change of the motor torque during the torque reduction control. As a result, during the torque reduction control, the rate of change of the motor torque is small, which can prevent the vehicle Ve from sliding downhill, thereby reducing discomfort to the user. On the other hand, during the torque return control, the rate of change of the motor torque is large, which can quickly return the vehicle Ve to its original position, etc., thereby providing the user with a sense of security.

[0103] Furthermore, in this embodiment, after it is determined that the vehicle is in a stall state, notification is continuously provided to the predetermined display unit 9 until the vehicle goes from the stall state to no longer in the stall state due to a change in drive instruction, such as from accelerator pedal operation to brake pedal operation. By providing such continuous notification, it is expected that the user will be able to operate the brake pedal or the like more quickly and escape from the stall state, for example, when the stall state is no longer present, compared to when the notification is stopped.

[0104] [Variations] Next, a modified example will be described. In the above embodiment, the temperature of the windings of the motor 1 is used as an example of the temperature of the motor 1, but it is not limited to the temperature of the windings of the motor 1 as long as the temperature of the motor 1 can be detected. For example, the temperatures of the rotor and stator that constitute the motor 1, or the surface temperature of the motor case, etc. may also be used. Alternatively, the temperature of the inverter 3a may be used as the temperature of the motor 1.

[0105] In the above-described embodiment, if the accelerator pedal is switched to the brake pedal while the torque recovery control is being executed, the motor torque is increased until a balanced torque is reached that maintains the vehicle Ve in a stopped state. On the other hand, if the brake pedal is operated while the motor torque is being increased until the balanced torque is reached, the control for increasing the motor torque may be terminated at the point in time when the brake pedal is operated, even if the motor torque has not yet increased to the balanced torque. This is because the operation of the brake pedal can prevent the vehicle Ve from rolling downhill.

[0106] Although the embodiments of the present invention have been described above with reference to the drawings, it goes without saying that the present invention is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

[0107] The control described in the above-described embodiment can be realized by executing a prepared control program on a computer. The control program is recorded on a computer-readable storage medium and executed by being read from the storage medium. The control program may be provided in a form stored on a non-transitory storage medium such as a flash memory, or may be provided via a network such as the Internet. The computer that executes the control program may be included in a control device, or may be included in an electronic device such as a smartphone, tablet terminal, or personal computer that can communicate with the control device, or may be included in a server device that can communicate with these control devices and electronic devices.

[0108] This specification describes at least the following: Note that the components in parentheses correspond to those in the above-described embodiments, but are not limited to these.

[0109] (1) A control device (control device 10) for a vehicle (vehicle Ve) equipped with a motor (motor 1) as a drive source, a stall determination unit (stall determination unit 11) that determines a stall state in which the motor is not rotating while torque of the motor is being generated based on a drive command; a torque control unit (torque control unit 12) that performs torque control to control the torque so that the rotation angle of the motor changes when it is determined that the stall state is occurring, The torque control unit The torque control is performed at a predetermined frequency based on the temperature of the motor. Vehicle control device.

[0110] According to (1), for example, compared to a case where torque control is continuously performed until the user notices that the vehicle is in a stall state, the amount of vehicle slippage can be reduced, or the possibility that the user will feel uncomfortable due to the continuous execution of torque control can be reduced. In other words, it is possible to escape from the stall state while suppressing the frequency of increasing or decreasing the torque of the motor.

[0111] (2) A control device for a vehicle according to (1), The torque control unit As the temperature of the motor increases, the frequency of performing the torque control increases. Vehicle control device.

[0112] According to (2), when the motor temperature is relatively high, the user is more likely to notice that the vehicle is stalling. In other words, when the motor temperature reaches the upper limit temperature, the motor output is limited to protect the motor, and the frequency of torque control is increased. On the other hand, when the motor temperature is relatively low, the frequency of torque control is relatively low, which reduces discomfort to the user due to vehicle vibrations, etc.

[0113] (3) A control device for a vehicle according to (1), The torque control unit When the stall state is eliminated due to the change in the drive command, the torque control is terminated. Vehicle control device.

[0114] According to (3), for example, if torque control is terminated without a drive command, there is a possibility that the vehicle will roll over. However, by terminating torque control based on the drive command, the possibility of the vehicle rolling over can be avoided or reduced.

[0115] (4) A control device for a vehicle according to (1), The torque control is a torque reduction control for reducing the torque so that the vehicle moves backward, and a torque restoration control for increasing the torque by an amount corresponding to the reduction in the torque reduction control, The torque control unit When the required driving force disappears due to a change in the driving command during execution of the torque control, a reduction rate of the torque, which is reduced in accordance with a timing of switching the driving command, is controlled so as to be different between the torque reduction control and the torque recovery control. Vehicle control device.

[0116] According to (4), by changing the driving instruction, such as by switching from the accelerator pedal to the brake pedal, it is possible to prevent the vehicle from rolling downhill, and by controlling the motor torque at different reduction rates, it is possible to reduce the possibility that the user will have the illusion that torque reduction control is being executed while torque recovery control is being executed, for example.

[0117] (5) A control device for a vehicle according to (4), The torque control unit When the required driving force disappears due to a change in the drive command while the torque reduction control is being executed, a torque reduction rate corresponding to the reduction in the required driving force is made smaller than the torque reduction rate in the torque reduction control. Vehicle control device.

[0118] According to (5), for example, by changing the driving instruction such as changing the pedal from the accelerator pedal to the brake pedal, it is possible to prevent the vehicle from rolling downhill.

[0119] (6) A control device for a vehicle according to (4) or (5), The torque control unit determining the torque increase rate so that the rotation angle of the motor changes in the forward direction of the vehicle at the end of the torque recovery control; Vehicle control device.

[0120] According to (6), for example, it is possible to prevent the vehicle from sliding down due to the inertia of the vehicle during torque recovery control.

[0121] (7) A control device for a vehicle according to (4) or (5), The torque control unit If the required driving force disappears due to a change in the driving command while the torque recovery control is being executed, the torque recovery control is continued until the torque is increased by an amount corresponding to the decrease. Vehicle control device.

[0122] According to (7), for example, if there is a change in driving instructions, such as switching from the accelerator pedal to the brake pedal, while the torque recovery control is being executed, the vehicle can be prevented from rolling down when switching from the accelerator pedal to the brake pedal, compared to when the torque recovery control is terminated before the balanced torque has been restored.

[0123] (8) A control device for a vehicle according to (4), The torque control is the torque balance control is further configured to maintain the vehicle in a stopped state while generating the torque based on the drive command after the torque recovery control is completed, The torque control unit When the requested driving force disappears due to a change in the driving command during execution of the torque balancing control, the torque is reduced at a predetermined reduction rate; The reduction rate is different from the reduction rate in the torque reduction control. Vehicle control device.

[0124] According to (8), for example, when a change in drive command occurs, such as when the accelerator pedal is switched to the brake pedal, during execution of torque balancing control after the torque recovery control ends, it is possible to prevent the vehicle from rolling downhill at the time of the change. Furthermore, by controlling the motor torque at a reduction rate different from the reduction rate in the torque reduction control, it is possible to reduce the possibility that the user may have an illusion that torque reduction control is being executed.

[0125] (9) A control device for a vehicle according to (1), The torque control is a torque reduction control for reducing the torque so that the vehicle moves backward, and a torque restoration control for increasing the torque by an amount corresponding to the reduction in the torque reduction control, a rate of change of the torque in the torque reduction control is smaller than a rate of change of the torque in the torque recovery control; Vehicle control device.

[0126] According to (9), for example, when the torque reduction control is being executed, the rate of change of the motor torque is small, which can prevent the vehicle from rolling downhill, thereby reducing discomfort to the user. On the other hand, when the torque recovery control is being executed, the rate of change of the motor torque is large, which can quickly return the vehicle to its original position, etc., giving the user a sense of security.

[0127] (10) A control device for a vehicle according to (1), The device further includes a notification control unit (notification control unit 13) that notifies the device of the stall state, The notification control unit The notification is continued until the stall state is eliminated due to the change in the drive instruction. Vehicle control device.

[0128] According to (10), for example, when the stall state is temporarily eliminated, it is expected that the user will be able to operate the brake pedal, etc., more quickly and escape from the stall state than if notification of the stall state were stopped. [Explanation of symbols]

[0129] 1 motor 10 Control device 11 Stall determination unit 12 Torque control section 13 Notification control section Vehicle

Claims

1. A control device for a vehicle equipped with a motor as a drive source, a stall determination unit that determines a stall state in which the motor is not rotating while torque is being generated by the motor based on a drive command; a torque control unit that performs torque control to control the torque so that the rotation angle of the motor changes when it is determined that the stall state is occurring, The torque control unit The torque control is performed at a predetermined frequency based on the temperature of the motor. Vehicle control device.

2. The vehicle control device according to claim 1, The torque control unit As the temperature of the motor increases, the frequency of performing the torque control increases. Vehicle control device.

3. The vehicle control device according to claim 1, The torque control unit When the stall state is no longer present due to the change in the drive command, the torque control is terminated. Vehicle control device.

4. The vehicle control device according to claim 1, The torque control is a torque reduction control for reducing the torque so that the vehicle moves backward, and a torque restoration control for increasing the torque by an amount corresponding to the reduction in the torque reduction control, The torque control unit When the required driving force disappears due to a change in the driving command during execution of the torque control, a reduction rate of the torque, which is reduced in accordance with a timing of switching the driving command, is controlled so as to be different between the torque reduction control and the torque recovery control. Vehicle control device.

5. The vehicle control device according to claim 4, The torque control unit When the required driving force disappears due to a change in the drive command while the torque reduction control is being executed, a torque reduction rate corresponding to the reduction in the required driving force is made smaller than the torque reduction rate in the torque reduction control. Vehicle control device.

6. The vehicle control device according to claim 4 or 5, The torque control unit determining the torque increase rate so that the rotation angle of the motor changes in the forward direction of the vehicle at the end of the torque recovery control; Vehicle control device.

7. The vehicle control device according to claim 4 or 5, The torque control unit If the required driving force disappears due to a change in the driving command while the torque recovery control is being executed, the torque recovery control is continued until the torque is increased by an amount corresponding to the decrease. Vehicle control device.

8. The vehicle control device according to claim 4, The torque control is the torque balance control is further configured to maintain the vehicle in a stopped state while generating the torque based on the drive command after the torque recovery control is completed, The torque control unit When the requested driving force disappears due to a change in the driving command during execution of the torque balancing control, the torque is reduced at a predetermined reduction rate; The reduction rate is different from the reduction rate in the torque reduction control. Vehicle control device.

9. The vehicle control device according to claim 1, The torque control is a torque reduction control for reducing the torque so that the vehicle moves backward, and a torque restoration control for increasing the torque by an amount corresponding to the reduction in the torque reduction control, a rate of change of the torque in the torque reduction control is smaller than a rate of change of the torque in the torque recovery control; Vehicle control device.

10. The vehicle control device according to claim 1, a notification control unit that notifies the user that the device is in the stall state; The notification control unit The notification is continued until the stall state is eliminated due to the change in the drive instruction. Vehicle control device.

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