Vehicle control device and control method

Abstract

To provide a vehicle control device which detects a vehicle being brought into a non-stop state early, and to provide a control method.SOLUTION: A vehicle control device according to an embodiment includes a controller which performs stop determination processing of a vehicle which travels by supplying a driving current to a traveling motor to drive a wheel. The stop determination processing determines that the vehicle is in a non-stop state when the driving current is not supplied to the traveling motor and a current flowing through the traveling motor is higher than or equal to a current threshold.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] There is known a technique for detecting, by a vehicle speed sensor, when a stopped vehicle starts to move due to its own weight or the like (for example, Patent Document 1).

[0003] Generally, a vehicle speed sensor detects the vehicle speed based on the increase or decrease in pulses outputted by the rotation of the wheels. It is known that when the moving speed of the vehicle is low, i.e., when the rotation speed of the wheels is low, the number of pulses detected per unit time is small, and therefore the vehicle speed detection accuracy is low. Therefore, when the vehicle speed is low, it is difficult to accurately detect the stopped / non-stop state of the vehicle based on the vehicle speed detected by the vehicle speed sensor.

[0004] In contrast, the conventional technology detects that the vehicle is in a non-stop state based on the time it takes for an integrated value of the number of pulses detected by a vehicle speed sensor to reach a predetermined value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-161903 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional technology, when the vehicle speed is low, it takes a long time for the integrated value to reach a predetermined value, and therefore it takes a long time to detect that the vehicle is not stopped. In other words, there is a risk of delay in detecting that the vehicle is not stopped.

[0007] The present invention has been made in view of the above, and has an object to detect early that a vehicle has entered a non-stop state. [Means for solving the problem]

[0008] A vehicle control device according to an embodiment includes a controller. The controller performs a process of determining whether the vehicle is stopped when a drive current is not supplied to the driving motor and a current flowing through the driving motor is equal to or greater than a current threshold. Effect of the Invention

[0009] According to one aspect of the embodiment, it is possible to detect early on that a vehicle has entered an unstopped state. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an outline of a vehicle in which a vehicle control device according to an embodiment is provided. [Diagram 2] FIG. 2 is a block diagram illustrating a control system including the control device according to the embodiment. [Diagram 3] FIG. 3 is a flowchart illustrating the brake control process according to this embodiment. [Figure 4] FIG. 4 is a flowchart illustrating the vehicle stop determination process according to this embodiment. [Diagram 5] FIG. 5 is a time chart illustrating the operation of the brake in a comparative example. [Figure 6] FIG. 6 is a time chart illustrating the operation of the brake in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device and a control method according to an embodiment will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to the present embodiment.

[0012] A vehicle 1 provided with a control device according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an outline of a vehicle 1 provided with a control device according to an embodiment.

[0013] The vehicle 1 is a vehicle such as an electric wheelchair or an electric cart, that is, a so-called personal mobility. The personal mobility is an electric vehicle that can accommodate one or two people. There are various types of personal mobility, such as a four-wheeled cart type, a wheelchair type, a three-wheeled vehicle, or a two-wheeled vehicle. There are also various types of two-wheeled personal mobility, such as an electric motorcycle, an electric bicycle, and a stand-up type vehicle with two wheels on the left and right in the traveling direction.

[0014] The vehicle 1 includes a traveling body 2, wheels 3, a traveling motor 4, a battery 5, a brake 6, and a control device 7. Here, only a part of the configuration of the vehicle 1 will be described. The vehicle 1 travels by supplying a drive current to the traveling motor 4 to drive the wheels 3.

[0015] There are multiple traction motors 4. The traction motors 4 are provided on the left and right wheels 3, respectively. For example, the traction motors 4 are provided on the left and right rear wheels, respectively. The traction motors 4 are in-wheel motors.

[0016] When a driving current is supplied from the battery 5, the traction motor 4 generates a driving force for driving the wheels 3.

[0017] The driving force generated by the traveling motor 4 is changed in response to the operation of an accelerator pedal 8, which is an accelerator operation input member. In addition, the vehicle speed of the vehicle 1 is changed in response to the operation of the accelerator pedal 8. As the amount of operation of the accelerator pedal 8 increases, the driving force generated by the traveling motor 4 increases, and the vehicle speed increases. The amount of operation of the accelerator pedal 8 is the amount that the accelerator pedal 8 is depressed.

[0018] Furthermore, as the amount of depression of the accelerator pedal 8 decreases while traveling, the driving force generated by the traction motor 4 decreases, and the vehicle speed decreases. When the amount of depression of the accelerator pedal 8 decreases while traveling, the traction motor 4 functions as a generator and generates a regenerative current (regenerative power). The regenerative current is supplied to the battery 5. Note that, with the traction motor 4 functioning as a generator, regenerative braking is applied to the vehicle 1, causing the vehicle 1 to decelerate further.

[0019] When the amount of operation of the accelerator pedal 8 is zero, no drive current is supplied from the battery 5 to the traction motor 4, and no drive force is generated to drive the wheels 3. Therefore, when the amount of operation of the accelerator pedal 8 becomes zero while the vehicle 1 is traveling, the vehicle 1 decelerates and then stops. When the vehicle 1 is stopped, the amount of operation of the accelerator pedal 8 is zero, and no drive current to drive the vehicle 1 is being supplied to the traction motor 4, the vehicle 1 is maintained in a stopped state.

[0020] It should be noted that the accelerator operation input member is not limited to the accelerator pedal 8. The accelerator operation input member may be, for example, any one of a lever, a joystick, and a steering wheel. For example, when the accelerator operation input member is a steering wheel, the driving force generated by the traveling motor 4 is changed by tilting the steering wheel back and forth or up and down. Also, when the accelerator operation input member is a steering wheel, the driving force generated by the traveling motor 4 may be changed by rotating the grip of the steering wheel.

[0021] The battery 5 supplies power to the electric devices of the vehicle 1. The electric devices include the traction motor 4, the control device 7, sensors, lights, and a monitor.

[0022] The brake 6 is provided, for example, on the driving motor 4. The brake 6 is an electromagnetic brake. When the brake 6 is activated, the rotating shaft of the driving motor 4 is rendered non-rotatable. In other words, when the brake 6 is activated, the wheels 3 are locked and non-rotatable. When the brake 6 is not activated, the rotating shaft of the driving motor 4 is rotatable. In other words, when the brake 6 is not activated, the wheels 3 are rotatable. Note that the brake 6 is not limited to an electromagnetic brake, and it is sufficient if the brake 6 is activated to lock the wheels 3 so that they do not rotate. Hereinafter, the state in which the brake 6 is not activated may be referred to as "non-activated."

[0023] The brake 6 is not limited to an electromagnetic brake. The brake 6 may be a friction brake or the like. A plurality of types of brakes may be provided on the vehicle 1 as the brake 6. For example, in addition to an electromagnetic brake, a friction brake or the like may be provided on the vehicle 1 as the brake 6.

[0024] The brakes 6, particularly the electromagnetic brakes, are automatically activated by the controller 11 when the vehicle 1 is stopped, there is no accelerator operation, and it is determined that the vehicle 1 is moving. It is possible to exclude the requirement that the vehicle 1 is moving as a condition for activating the brakes 6, but by including the requirement that the vehicle 1 is moving, activation of the brakes 6 is suppressed when the need for activation of the brakes 6 is low. This allows the vehicle 1 to conserve power.

[0025] The brake 6 may be actuated by the operation of a brake operation input member (e.g., a brake pedal and a brake lever) by a user (driver). That is, the brake 6 may be actuated by manual operation. For example, an electromagnetic brake may be automatically actuated as described above, and a friction brake may be actuated by manual operation.

[0026] Next, the control device 7 will be described with reference to Fig. 2. Fig. 2 is a block diagram illustrating a control system including the control device 7 according to the embodiment. The control device 7 is a vehicle control device that controls the vehicle 1, and is, for example, a VCU (Vehicle Control Unit).

[0027] The control device 7 includes a storage unit 10 and a controller 11. The storage unit 10 is realized by a storage device such as a RAM (Random Access Memory), a flash memory, or a disk device.

[0028] The controller 11 is a component equivalent to a so-called processor or control unit. The controller 11 is realized by a CPU (Central Processing Unit), MPU (Micro Processing Unit), or the like, executing various programs stored in the storage unit 10 using a RAM as a working area. The controller 11 can also be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0029] To the controller 11, a vehicle speed sensor 20 (rotation speed sensor), an accelerator pedal sensor 21, a first current sensor 22, a second current sensor 23, and a G sensor 24 are connected.

[0030] The vehicle speed sensor 20 detects the vehicle speed of the vehicle 1. The vehicle speed sensor 20 is provided in a power transmission path between the driving motor 4 and the wheels 3. The vehicle speed sensor 20 detects the vehicle speed of the vehicle 1, for example, by detecting the number of rotations of the rotating shaft of the driving motor 4, the wheel axle, or the wheels. The vehicle speed sensor 20 detects the vehicle speed by detecting pulses output by the rotation of the rotating shaft of the driving motor 4, etc. The vehicle speed sensor 20 is provided for each driving motor 4. For example, the average value of the values ​​detected by each vehicle speed sensor 20 is detected as the vehicle speed.

[0031] When the rotation speed of the rotary shaft of the traveling motor 4 is detected, the vehicle speed may be referred to as the motor rotation speed (rotation speed). When the rotation speed of the rotary shaft of the traveling motor 4 is detected, the vehicle speed sensor 20 may be referred to as the motor rotation speed (rotation speed) sensor.

[0032] The accelerator pedal sensor 21 detects the amount of operation of the accelerator pedal 8. Specifically, the accelerator pedal sensor 21 detects the amount of depression of the accelerator pedal 8.

[0033] A first current sensor 22 is provided for each traction motor 4. In the case of a vehicle 1 provided with multiple traction motors 4, multiple first current sensors 22 are provided. The first current sensor 22 detects the motor current. The motor current is a current flowing through the traction motor 4. The motor current includes a drive current for driving the vehicle 1 and a regenerative current generated by the traction motor 4. When the wheels 3 are driven by the traction motor 4, the first current sensor 22 detects the drive current flowing from the battery 5 to the inverter 30. Furthermore, when the traction motor 4 generates power, the first current sensor 22 detects the regenerative current flowing from the inverter 30 to the battery 5.

[0034] The second current sensor 23 is provided in the battery 5. The second current sensor 23 detects the battery current. The battery current is the input / output current of the battery 5. The battery current includes the current flowing from the battery 5 and the current flowing to the battery 5. The battery current is the current in all of the electrical devices of the vehicle 1. The battery current includes the current flowing to the control device 7, the current flowing to the running motor 4, and the current flowing to the sensors. Note that when the running motor 4 generates power, the battery current includes a regenerative current.

[0035] The G sensor 24 detects the inclination of the vehicle 1 in the longitudinal direction. Specifically, the G sensor 24 detects the inclination of the road surface on which the vehicle 1 runs or the road surface on which the vehicle 1 stops. That is, the G sensor 24 detects the inclination of the vehicle 1. Hereinafter, the inclination of the road surface means the inclination of the vehicle 1 in the longitudinal direction. The G sensor 24 may be provided in the control device 7.

[0036] The controller 11 is connected to an inverter 30 and a brake 6. An inverter 30 is provided for each travel motor 4. For example, if two travel motors 4 are provided, two inverters 30 are provided. The inverter 30 controls the driving of the travel motor 4 based on instruction signals such as the number of rotations from the controller 11.

[0037] The controller 11 generates a command signal for the rotation speed of the driving motor 4 in response to the operation of the accelerator pedal 8, and outputs a drive signal based on the generated command signal to the inverter 30.

[0038] Furthermore, the controller 11 generates an instruction signal for activating the brake 6 and an instruction signal for putting the brake 6 into an activated state or a deactivated state, and outputs the generated instruction signal to the brake 6. In other words, the controller 11 controls the state of the brake 6.

[0039] The controller 11 executes a brake control process. Next, the brake control process according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a flowchart for explaining the brake control process according to this embodiment. The brake control process described below is repeatedly executed when the power supply of the vehicle 1 is ON.

[0040] The controller 11 acquires the amount of operation of the accelerator pedal 8 (S100). Specifically, the controller 11 acquires information relating to the amount of operation of the accelerator pedal 8 from the accelerator pedal sensor 21.

[0041] The controller 11 determines whether or not the accelerator is being operated (S101). Specifically, the controller 11 determines whether or not the accelerator is being operated based on the amount of operation of the accelerator pedal 8. If the amount of operation of the accelerator pedal 8 is zero, the controller 11 determines that the accelerator is not being operated. Note that if the accelerator is not being operated, no drive current is supplied to the traveling motor 4. If the amount of operation of the accelerator pedal 8 is not zero, the controller 11 determines that the accelerator is being operated.

[0042] When it is determined that an accelerator operation has been performed (S101: Yes), the controller 11 sets the history flag to "0" (S102). When the history flag is already set to "0", the controller 11 maintains the history flag at "0".

[0043] The history flag is information for distinguishing whether the vehicle 1 is in a state before it goes from a traveling state to a stopped state (history flag "0"), or in a state after it goes from a traveling state to a stopped state (history flag "1"). The history flag becomes "0" when there is an accelerator operation (when the vehicle is in a traveling state). Once the history flag becomes "0", it is maintained at "0" until it is determined that the vehicle 1 has stopped. Specifically, even if there is no accelerator operation, the history flag is maintained at "0" until it is determined that the vehicle 1 has stopped in the stopped vehicle determination process described below. When it is determined that the vehicle 1 has stopped in the stopped vehicle determination process described below, the history flag becomes "1".

[0044] Next, the controller 11 puts the brake 6 into a non-operated state (S103). If the brake 6 is in an activated state, the controller 11 puts the brake 6 into a non-operated state and releases the operation of the brake 6. This enables the rotation shaft of the travel motor 4 to rotate, and the wheels 3 to rotate. Therefore, for example, when the accelerator pedal 8 is depressed when the vehicle 1 is stopped, the vehicle 1 moves. Note that, as will be described later, after the brake 6 is activated, the brake 6 is maintained in an activated state until the accelerator is operated.

[0045] Furthermore, if the brakes 6 are already in a deactivated state, the controller 11 maintains the brakes 6 in a deactivated state.

[0046] In this way, when the accelerator operation is being performed, that is, when the user intends to drive the vehicle 1, the brake 6 is in a deactivated state. Note that, if the brake 6 is already in a deactivated state, step S103 may be skipped. In this case, the brake 6 is maintained in a deactivated state. The same applies to the process of step S103 described below.

[0047] When it is determined that the accelerator operation is not performed (S101: No), the controller 11 acquires the inclination of the road surface (S104). Specifically, the controller 11 acquires information on the inclination of the road surface from the G sensor 24.

[0048] Next, the controller 11 determines whether the vehicle 1 is inclined (S105). Specifically, the controller 11 determines whether the acquired inclination of the road surface is equal to or greater than a predetermined angle. The predetermined angle is a preset angle. For example, the predetermined angle is an angle at which the stopped vehicle 1 starts to move when the accelerator pedal 8 is not operated. The predetermined angle may be set according to the weight of the vehicle 1. The weight of the vehicle 1 includes the weight of the vehicle 1 itself and the weight of passengers. For example, the weight of the vehicle 1 is detected by a weight sensor. If the inclination of the road surface is equal to or greater than the predetermined angle, the controller 11 determines that the vehicle 1 is inclined. If the inclination of the road surface is less than the predetermined angle, the controller 11 determines that the vehicle 1 is not inclined.

[0049] If the vehicle 1 is not tilted (S105: No), the controller 11 deactivates the brakes 6 (S103).

[0050] If the vehicle 1 is tilting (S105: Yes), the controller 11 determines whether the brake 6 is in an applied state (S106). If the brake 6 is in an applied state (S106: Yes), the controller 11 maintains the brake 6 in an applied state and ends the current processing. If the brake 6 is in an applied state, the brake 6 is maintained in an applied state until an accelerator operation is performed, that is, until it is determined in step S101 that an accelerator operation is performed (S101: Yes).

[0051] If the brake 6 is not in an applied state (S106: No), that is, if the brake 6 is in an inactivated state, the controller 11 executes a vehicle stop determination process (S107). Details of the vehicle stop determination process will be described later. In the vehicle stop determination process, it is determined whether the vehicle 1 is in a stopped state or not.

[0052] Next, the controller 11 determines whether or not the history flag is "1" (S108). If the history flag is "1", it has been determined that the vehicle 1 is in a stopped state by the vehicle stop determination process in the previous process.

[0053] If the history flag is not "1" (S108: No), that is, if the history flag is "0", the controller 11 determines whether or not the vehicle 1 is in a stopped state (S109). In other words, the controller 11 determines whether or not the determination result of the vehicle stop determination process in step S107 is a stopped state.

[0054] If the vehicle 1 is stopped (S109: Yes), the controller 11 sets the history flag to "1" (S110). Specifically, if the history flag is "0" (S108: No) and the controller 11 determines that the vehicle 1 is stopped (S109: Yes), the controller 11 determines that the traveling vehicle 1 has become stopped, and sets the history flag to "1." Next, the controller 11 deactivates the brake 6 (S103).

[0055] If the vehicle 1 is not in a stopped state (S109: No), that is, if the vehicle 1 is not in a stopped state, the controller 11 deactivates the brake 6 (S103). Before it is determined that the vehicle 1 is in a stopped state, the brake 6 is in an inactivated state. For example, if the accelerator operation is stopped while the vehicle 1 is traveling and the vehicle 1 is decelerating, or otherwise, if the vehicle 1 is not in a stopped state, the brake 6 is not activated.

[0056] If the history flag is "1" (S108: Yes), the controller 11 determines whether or not the vehicle 1 is in a stopped state (S111). That is, the controller 11 determines whether or not the vehicle 1 is in a stopped state when the vehicle 1 has once been determined to be in a stopped state and the history flag is set to "1". In other words, the controller 11 determines whether or not the determination result of the vehicle stop determination process in step S107 is a stopped state.

[0057] When the vehicle 1 is not in a stopped state (S111: No), that is, when the vehicle 1 is in a non-stop state, the controller 11 activates the brake 6 (S112). Here, the history flag is in a "1" state, and it is determined that the vehicle 1 is not in a stopped state. Specifically, the vehicle 1 is once determined to be in a stopped state, and the vehicle 1 is determined to be in a non-stop state, even though the accelerator is not operated. This state is a state in which the vehicle 1 starts moving without the accelerator being operated. Therefore, the controller 11 activates the brake 6 to stop the vehicle 1 from starting to move without the accelerator being operated. The vehicle 1 starts to move when the vehicle 1 is stopped on an inclined surface, for example. The vehicle 1 starts to move when the vehicle 1 is not intended by the user. For example, the vehicle 1 starts to move when the vehicle 1 stopped on an inclined surface slides down due to its own weight. When the controller 11 determines that the vehicle 1 is in a non-stop state in the stop determination process, the controller 11 activates the brake 6.

[0058] The brake 6 is actuated on the condition that the history flag is "1" (S108: Yes). That is, the brake 6 is actuated on the condition that the vehicle 1 is once determined to be in a stopped state (S109: Yes) and the history flag is set to "1" (S110). In other words, when the vehicle 1 is in a state in the middle of decelerating from a traveling state until the vehicle 1 is once determined to be in a stopped state and the history flag is set to "1", the brake 6 is not automatically actuated. In addition, in this case, when the vehicle 1 is equipped with a brake that can be manually actuated by the user, the actuation of the manually actuable brake is not suppressed (prohibited). Therefore, when the necessity of actuating the brake 6 is low, that is, when the vehicle 1 is not moving unintentionally by the user, the controller 11 can suppress the automatic actuation of the brake 6. Therefore, the controller 11 can improve the usability of the vehicle 1. In addition, the controller 11 can suppress the power consumed to actuate the brake 6.

[0059] Next, the vehicle stop determination process according to the embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart illustrating the vehicle stop determination process according to the embodiment. The vehicle stop determination process is a process executed in step S106 in Fig. 3. Therefore, since this vehicle stop determination process is a process executed after it is determined in step S101 in Fig. 3 that no accelerator operation has been performed, the process is executed in a state where no accelerator operation is being performed. In other words, the vehicle stop determination process is executed in a state where no drive current is being supplied to the traveling motor 4.

[0060] The controller 11 acquires the rotation speed (S200). Specifically, the controller 11 acquires information related to the rotation speed detected by the vehicle speed sensor 20.

[0061] The controller 11 determines whether the rotation speed is less than the rotation speed threshold (S201). The rotation speed threshold is a preset value, and is a rotation speed at which it is possible to determine whether the vehicle 1 is moving. For example, the rotation speed threshold is a minimum rotation speed at which it is possible to determine whether the vehicle 1 is moving using the vehicle speed sensor 20.

[0062] When the rotation speed is equal to or greater than the rotation speed threshold (S201: No), the controller 11 determines that the vehicle 1 is not in a stopped state, that is, that the vehicle 1 is in a non-stop state (S202). That is, the stop determination process performs a first determination process of determining that the vehicle 1 is in a non-stop state when the rotation speed detected by the vehicle speed sensor 20 is equal to or greater than the rotation speed threshold.

[0063] When the rotation speed is less than the rotation speed threshold value (S201: Yes), the controller 11 acquires the motor current (S203). Specifically, the controller 11 acquires information about the motor current from the first current sensor 22.

[0064] Next, the controller 11 determines whether the first current sensor 22 is normal or not (S204). Specifically, the controller 11 determines whether the motor current is within a normal range. The normal range is a range set in advance. The normal range is a range within which the motor current falls when no abnormality occurs in the first current sensor 22. If the motor current is within the normal range, the controller 11 determines that the first current sensor 22 is normal. If the motor current is a value outside the normal range, the controller 11 determines that the first current sensor 22 is not normal, i.e., is abnormal.

[0065] When the controller 11 determines that the first current sensor 22 is not normal (S204: No), that is, when the controller 11 determines that the first current sensor 22 is abnormal, the controller 11 acquires the battery current (S205). Specifically, the controller 11 acquires information about the battery current from the second current sensor 23.

[0066] Next, the controller 11 estimates the motor current (S206). The controller 11 estimates the motor current based on the battery current and the current flowing in electric devices other than the traction motor 4 (hereinafter referred to as "other electric devices").

[0067] The current flowing through the other electric appliances is set in advance. The current flowing through the other electric appliances is stored, for example, in the memory unit 10 for each other electric appliance. The controller 11 detects the activation status of the other electric appliances. The controller 11 reads out the current flowing through the other activated electric appliances from the memory unit 10. The controller 11 then calculates the total value of the current flowing through the other activated electric appliances. The controller 11 estimates the motor current from the total value of the current flowing through the other activated electric appliances and the battery current. The estimated motor current is a current corresponding to the regenerative current.

[0068] The controller 11 determines whether the motor current is less than the current threshold (S207). The current threshold is a preset value. When the accelerator is not operated and the vehicle 1 changes from a stopped state to a non-stop state, the driving motor 4 generates electricity, generating a regenerative current. The current threshold is the current generated in such a case. The stoppage determination process performs a second determination process for determining the running state of the vehicle 1 based on the motor current flowing through the driving motor 4 when the rotation speed is less than the rotation speed threshold and the first determination process determines that the vehicle 1 is in a stopped state.

[0069] If the controller 11 determines that the first current sensor 22 is normal (S204: Yes), the controller 11 compares the motor current detected by the first current sensor 22 with the current threshold value. If the controller 11 determines that the first current sensor 22 is abnormal (S204: No), the controller 11 compares the estimated motor current with the current threshold value. That is, in the vehicle stop determination process, if the motor current detected by the first current sensor 22 is outside the normal range, the vehicle stop state is determined based on the battery current.

[0070] If the motor current is less than the current threshold value (S207: Yes), the controller 11 determines that the vehicle 1 is in a stopped state (S208).

[0071] When the motor current is equal to or greater than the current threshold value (S207: No), the controller 11 determines that the vehicle 1 is in a non-stop state (S202).

[0072] In this way, the vehicle stop determination process determines that the vehicle 1 is in a non-stop state when no drive current is supplied to the driving motor 4 (the accelerator is not being operated (S101: No in FIG. 3)) and the motor current (regenerative current) is equal to or greater than the current threshold (S207: No). In other words, if the motor current flowing through the driving motor 4 when no drive current is supplied to the driving motor 4 becomes equal to or greater than the current threshold, the vehicle stop determination process determines that the vehicle 1 has changed from a stopped state to a non-stop state because a regenerative current is flowing due to the vehicle 1 moving (the wheels 3 rotating).

[0073] The vehicle stop determination process is not executed when it is determined in step S104 of Fig. 3 that the vehicle 1 is not tilted, i.e., the vehicle 1 is not on an inclined surface. Therefore, when it is determined that the vehicle 1 is not on an inclined surface, the vehicle 1 is not determined to be in a non-stop state. In other words, when it is determined that the vehicle 1 is not on an inclined surface, the vehicle stop determination process does not determine that the vehicle 1 is in a non-stop state.

[0074] Next, the operation of the brake 6 in the control device 7 according to the comparative example will be described with reference to FIG. 5. FIG. 5 is a time chart for explaining the operation of the brake 6 in the comparative example. In the control device 7 according to the comparative example, it is determined whether the vehicle 1 is in a stopped state or a non-stop state based on the number of rotations detected by the vehicle speed sensor 20. That is, this is a time chart for explaining the processing operation in the case where steps S203 to S207 in FIG. 4 are deleted. Here, an example will be described in which the accelerator operation is stopped while the vehicle 1 is traveling, and the vehicle 1 stops on an inclined surface. The same applies to FIG. 6 described below.

[0075] FIG. 5 shows the accelerator operation, the power running state of the traction motor 4, the determination state of whether the vehicle 1 is stopped or not, the history flag, the state of the brake 6, and the rotation speed.

[0076] At time t0, the vehicle 1 is traveling with the accelerator operated, but the accelerator is no longer operated. As a result, no drive current is supplied to the traveling motor 4, and the power running state of the traveling motor 4 becomes a non-driven state. Furthermore, since the traveling motor 4 becomes a non-driven state, the rotation speed detected by the vehicle speed sensor 20 decreases. The vehicle 1 is not stopped. Furthermore, the history flag is "0". Furthermore, the brake 6 is in a non-operated state.

[0077] At time t11, when the rotation speed falls below the rotation speed threshold, it is determined that the vehicle 1 is in a stopped state, and the history flag becomes "1." After the vehicle 1 stops on the inclined surface, for example, when the vehicle 1 starts to move due to its own weight, the rotation speed gradually increases.

[0078] However, when the rotation speed detected by the vehicle speed sensor 20 is less than the rotation speed threshold value, the vehicle 1 is determined to be in a stopped state, and the brakes 6 are not applied and are maintained in a deactivated state.

[0079] At time t12, when the rotation speed detected by the vehicle speed sensor 20 becomes equal to or greater than the rotation speed threshold value, the vehicle 1 is determined to be in a non-stop state. Because the history flag is "1" and the vehicle 1 is in a non-stop state, the brake 6 is activated and the brake 6 is in an activated state. This causes the rotation speed to become zero. Also, because the rotation speed becomes zero, the vehicle 1 is determined to be in a stopped state. The time during which the vehicle 1 is in a non-stop state is very short, but for the sake of explanation, the time during which the vehicle is in a non-stop state is described as being longer than it actually is.

[0080] At time t13, when the accelerator is operated, the history flag becomes "0", and the brake 6 is deactivated. A drive current is supplied to the traveling motor 4, and the power running state of the traveling motor 4 becomes a driving state. The rotation speed also increases.

[0081] At time t14, when the rotation speed detected by the vehicle speed sensor 20 becomes equal to or greater than the rotation speed threshold value, it is determined that the vehicle 1 is in a non-stop state.

[0082] Thus, in the comparative example, when the vehicle 1 starts moving after it has stopped even without accelerator operation, the brake 6 does not operate and the vehicle 1 does not stop until the rotation speed reaches or exceeds the rotation speed threshold value. Therefore, there is a risk that the time from when the vehicle 1 starts moving until the brake 6 operates to stop the vehicle 1 may be long.

[0083] Next, the operation of the brake 6 according to the embodiment will be described with reference to Fig. 6. Fig. 6 is a time chart illustrating the operation of the brake 6 according to the embodiment.

[0084] FIG. 6 shows the accelerator operation state, the power running state of the traction motor 4, the stopped / non-stop state of the vehicle 1, the history flag, the state of the brake 6, and the rotation speed detected by the vehicle speed sensor 20, as well as the motor current.

[0085] As in the comparative example in FIG. 5, the vehicle 1 is traveling with the accelerator operated, but at time t0, the accelerator is no longer operated. As a result, no drive current is supplied to the traveling motor 4, and the power running state of the traveling motor 4 becomes a non-driving state. In addition, since the traveling motor 4 becomes a non-driving state, the rotation speed detected by the vehicle speed sensor 20 decreases. In addition, since the vehicle 1 is moving when the traveling motor 4 is not in a driving state, a regenerative current flows through the traveling motor 4, but as the rotation speed decreases, the motor current also decreases. In addition, the vehicle 1 is in a non-stop state. In addition, the history flag is "0". In addition, the brake 6 is in an inoperative state.

[0086] At time t1, even if the rotation speed detected by the vehicle speed sensor 20 falls below the rotation speed threshold, the motor current is equal to or greater than the current threshold, so it is determined that the vehicle 1 is in a non-stop state.

[0087] At time t2, when the motor current falls below the current threshold, it is determined that the vehicle 1 is in a stopped state, and the history flag becomes "1." After the vehicle 1 stops on an inclined surface, for example, if the vehicle 1 starts to move due to its own weight, the rotation speed gradually increases. Also, a regenerative current is generated in the traction motor 4, and the motor current gradually increases.

[0088] At time t3, when the motor current becomes equal to or greater than the current threshold value, the vehicle 1 is determined to be in a non-stop state. Because the history flag is "1" and the vehicle 1 is in a non-stop state, the brake 6 is activated and the brake 6 enters an activated state. As a result, the rotation speed and motor current become zero. Also, because the rotation speed and motor current become zero, the vehicle 1 is determined to be in a stopped state. The time during which the vehicle 1 is in a non-stop state is very short, but for the sake of explanation, the time during which the vehicle is in a non-stop state is described as being longer than it actually is.

[0089] When the motor current becomes equal to or greater than the current threshold, the rotation speed is less than the rotation speed threshold. That is, in the embodiment, the brake 6 is actuated before the rotation speed detected by the vehicle speed sensor 20 becomes equal to or greater than the rotation speed threshold. Therefore, in the embodiment, the brake 6 is actuated earlier than in the comparative example, and the vehicle 1 is stopped earlier.

[0090] At time t4, when the accelerator is operated, the history flag becomes "0" and the brake 6 is deactivated. A drive current is supplied to the traveling motor 4, and the power running state of the traveling motor 4 becomes a driving state. The rotation speed and the motor current also increase.

[0091] At time t5, when the motor current detected by the first current sensor 22 becomes equal to or greater than the current threshold value, it is determined that the vehicle 1 is in a non-stop state.

[0092] The controller 11 performs a stop determination process for the vehicle 1, which runs by supplying a drive current to the driving motor 4 to drive the wheels 3. The stop determination process determines that the vehicle 1 is in a non-stop state when a drive current is not supplied to the driving motor 4 and the motor current is equal to or greater than a current threshold value.

[0093] This allows the controller 11 to determine whether the vehicle 1 is in a stopped state or a non-stop state based on the motor current, and to detect early that the vehicle 1 has entered a non-stop state. For example, when the vehicle 1 starts to move due to its own weight or the like after it has once entered a stopped state, the controller 11 can detect early that the vehicle 1 has started to move.

[0094] When the controller 11 determines that the vehicle 1 is in a non-stop state in the vehicle stop determination process, it activates the brake 6. In this way, the controller 11 can stop the vehicle 1 that is in a non-stop state. For example, when the vehicle 1 starts to move due to its own weight or the like after it has once been in a stopped state, the controller 11 can stop the vehicle 1 that has started to move.

[0095] The brake 6 is an electromagnetic brake provided on the traveling motor 4. With this, for example, when the vehicle 1 starts to move due to its own weight after being stopped once, the controller 11 can activate the brake 6 early. Therefore, the controller 11 can quickly stop the vehicle 1 that has started to move.

[0096] In the vehicle stop determination process, when the motor current, which is the regenerative current generated by the traveling motor 4, is equal to or greater than a current threshold value, it is determined that the vehicle is in a non-stop state.

[0097] This allows the controller 11 to detect early on that the vehicle 1 has started to move based on the regenerative current when the vehicle 1 has stopped once without an accelerator operation and then starts to move due to its own weight or the like.

[0098] In the vehicle stop determination process, when no drive current is supplied to the traction motor 4 and the motor current is equal to or greater than the current threshold, it is determined that the vehicle 1 has changed from a stopped state to a non-stop state.

[0099] This enables the controller 11 to quickly determine, based on the motor current, whether the vehicle 1 has started to move in a state in which the accelerator pedal is not being operated.

[0100] The vehicle stop determination process performs a first determination process to determine that the vehicle is not stopped when the rotation speed detected by the vehicle speed sensor 20 provided in the power transmission path between the driving motor 4 and the wheels 3 is equal to or greater than the rotation speed threshold. The vehicle stop determination process performs a second determination process to determine the running state based on the motor current when the first determination process determines that the vehicle is stopped.

[0101] As a result, the controller 11 can determine whether the vehicle 1 is stopped or not by the second determination process using the motor current, even if the rotation speed is below a value at which the vehicle speed sensor 20 cannot accurately detect the rotation speed.

[0102] In the vehicle stop determination process, if it is determined that the vehicle 1 is not on an inclined surface, it is not determined that the vehicle is not in a non-stop state.

[0103] As a result, when the vehicle 1 is not on an inclined surface, the controller 11 does not activate the brakes 6. Therefore, the controller 11 can suppress the power consumed by the activation of the brakes 6.

[0104] In the vehicle stop determination process, when the motor current is outside the normal range, a vehicle stop state is determined based on the battery current.

[0105] As a result, even if the first current sensor 22 that detects the motor current fails, the controller 11 can determine whether the vehicle 1 is stopped or not using the battery current detected by the second current sensor 23.

[0106] In the above embodiment, when the vehicle 1 is tilted (S105: Yes), that is, when the vehicle 1 is on a slope, the controller 11 executes the process from step S106 onwards. Then, the controller 11 activates the brake 6 to suppress the vehicle 1 from starting to move without an accelerator operation, but this is not limited to this. The controller 11 may execute the process from step S106 onwards even when the vehicle 1 is not on a slope. That is, the controller 11 may activate the brake 6 when the vehicle 1 starts to move without an accelerator operation even when the vehicle 1 is not on a slope. In this case, for example, the process of step S105 in FIG. 3 is not executed.

[0107] Note that the controller 11 may determine that the first current sensor 22 is normal when at least one of the motor currents detected by the multiple first current sensors 22 has a value within the normal range. In other words, the controller 11 determines that there is a normal first current sensor 22 among the multiple first current sensors 22. When at least one of the multiple motor currents has a value within the normal range, the controller 11 determines whether or not the motor current is less than the current threshold value based on the motor current within the normal range.

[0108] Furthermore, when all of the motor currents detected by the multiple first current sensors 22 are outside the normal range, the controller 11 determines that the first current sensors 22 are abnormal. In other words, the controller 11 determines that there is no normal first current sensor 22 among the multiple first current sensors 22. When all of the multiple motor currents are outside the normal range, the controller 11 estimates the motor current based on the battery current.

[0109] Furthermore, the vehicle 1 may be provided with a release switch that can release the brake 6 and put it into a non-operated state by a means other than operating the accelerator.

[0110] In the above embodiment, an example in which the vehicle 1 is a personal mobility vehicle has been described, but the present invention is not limited to this. The vehicle 1 may be various vehicles such as a general passenger car. The processing of the above embodiment is applicable to various vehicles such as a general passenger car.

[0111] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0112] 1 vehicle 3 wheels 4. Driving motor 5 Battery 6. Brakes 7 Control device (vehicle control device) 8. Accelerator pedal 11 Controller 20 Vehicle speed sensor 21 Accelerator pedal sensor 22 First current sensor 23 Second current sensor 24 G Sensor

Claims

1. A controller is provided for carrying out a process of determining whether or not a vehicle is stopped when the vehicle is traveling by supplying a drive current to a driving motor to drive wheels, The vehicle stop determination process determines that the vehicle is in a non-stop state when a drive current is not supplied to the driving motor and a current flowing through the driving motor is equal to or greater than a current threshold.

2. The vehicle control device according to claim 1 , wherein the controller activates a brake when the vehicle is determined to be in the non-stop state in the stop determination process.

3. The vehicle control device according to claim 2 , wherein the brake is an electromagnetic brake provided on the driving motor.

4. The vehicle control device according to claim 1 , wherein the vehicle stop determination process determines that the vehicle is in the non-stop state when a regenerative current generated by the driving motor is equal to or greater than the current threshold value.

5. 2. The vehicle control device according to claim 1, wherein the vehicle stop determination process determines that the vehicle has changed from a stopped state to a non-stop state when a drive current is not supplied to the driving motor and a current flowing through the driving motor becomes equal to or greater than a current threshold value.

6. The vehicle stop determination process includes: a first determination process for determining that the vehicle is in the non-stop state when a rotation speed detected by a rotation speed sensor provided in a power transmission path between the driving motor and wheels is equal to or greater than a rotation speed threshold value; 2. The vehicle control device according to claim 1, further comprising: a second determination process for determining a traveling state based on a current flowing through the driving motor when the first determination process determines that the vehicle is in a stopped state.

7. The vehicle control device according to claim 1 , wherein the vehicle stop determination process does not determine that the vehicle is in a non-stop state when it is determined that the vehicle is not on an inclined surface.

8. The vehicle control device according to claim 1 , wherein the vehicle stop determination process determines whether the vehicle is stopped based on an input / output current of a battery when a current flowing through the driving motor is outside a normal range.

9. A method for controlling a vehicle that runs by supplying a drive current to a driving motor to drive wheels, the method comprising the steps of: A control method comprising: performing a vehicle stop determination process for determining that the vehicle is in a non-stop state when a drive current is not supplied to the driving motor and the current flowing through the driving motor is equal to or greater than a current threshold value.

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