Vehicle control device, vehicle and abnormality sensing method

Abstract

To provide a vehicle control device, a vehicle and an abnormality sensing method which can detect an abnormality of a mechanical brake, even when braking force is generated, by the mechanical brake, on one wheel, of two wheels.SOLUTION: A vehicle control device according to an embodiment is loaded on a vehicle that is driven by motors provided on two wheels respectively, in which a mechanical brake provided on one wheel is operated by brake operation by a driver. The vehicle control device comprises a controller that detects an abnormality of the mechanical brake. The controller detects a first abnormality which the mechanical brake is abnormally operated, when the vehicle is running forward and when a difference in current value between the motors is equal to or greater than a first threshold in a state where the mechanical brake is not operated.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Braking of vehicles such as senior cars and electric wheelchairs is generally performed by regenerative braking, which occurs when the accelerator pedal is slightly depressed. However, regenerative braking alone may not provide sufficient braking force. For this reason, it is possible to consider providing mechanical brakes on the wheels. For vehicles equipped with mechanical brakes, it is desirable to detect abnormalities in the mechanical brakes when they occur. This makes it possible to detect abnormalities such as failure and deterioration of the mechanical brakes without visually inspecting the consumable parts of the mechanical brakes.

[0003] A known technique for detecting an abnormality in a mechanical brake is, for example, a technique for comparing motor current values ​​of electric actuators that are provided on the left and right wheels of a vehicle and that operate the mechanical brakes (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 104682 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above technology, the motor current values ​​are compared when braking force is generated on the left and right wheels, so if braking force is generated by the mechanical brake on one of the left and right wheels, an abnormality in the mechanical brake cannot be detected.

[0006] The present invention has been made in consideration of the above, and aims to detect an abnormality in a mechanical brake even when braking force is generated by the mechanical brake on one of two wheels. [Means for solving the problem]

[0007] A vehicle control device according to one aspect of the embodiment is mounted on a vehicle that is driven by motors provided on two wheels, each of which operates a mechanical brake provided on one of the wheels when the driver brakes. The vehicle control device includes a controller that detects an abnormality in the mechanical brake. When the difference in current values ​​of the motors when the vehicle is traveling straight and the mechanical brake is not operated is equal to or greater than a first threshold, the controller detects a first abnormality, which indicates that the mechanical brake is operating abnormally.

[0008] A vehicle control device according to another aspect of the embodiment is mounted on a vehicle that is driven by motors provided on two wheels, each of which operates a mechanical brake provided on one of the wheels when the driver brakes. The vehicle control device includes a controller that detects an abnormality in the mechanical brake. When the difference in current values ​​of the motors when the vehicle is traveling straight and the mechanical brake is operated is less than a second threshold, the controller detects a second abnormality in which the mechanical brake is not operating. [Effects of the Invention]

[0009] In a vehicle equipped with a vehicle control device according to an embodiment, when a mechanical brake is activated, the current value of the motor provided on the wheel on which the mechanical brake is activated becomes larger than the current values ​​of the motors provided on the other wheels. Therefore, the vehicle control device according to an embodiment detects an abnormality in the mechanical brake based on the activation state of the mechanical brake and the difference in the current values ​​of the motors. Therefore, the vehicle control device can detect an abnormality in the mechanical brake even when braking force is generated by the mechanical brake provided on one wheel. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an outline of a vehicle according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating the control device according to the embodiment. [Figure 3] FIG. 3 is a flowchart illustrating the first abnormality detection process according to the embodiment. [Figure 4] FIG. 4 is a flowchart illustrating the second abnormality detection process according to the embodiment. [Figure 5] FIG. 5 is a time chart showing the establishment state of the abnormality detection condition when a first abnormality occurs, the operation state of the brake lever, the difference in current value, and the state of the first abnormality determination flag. [Figure 6] FIG. 6 is a time chart showing the establishment state of the abnormality detection condition when a second abnormality occurs, the operation state of the brake lever, the difference in current value, and the state of the second abnormality determination flag. [Figure 7] FIG. 7 is a time chart showing the establishment state of the abnormality detection condition when the third abnormality occurs, the operation state of the brake lever, the difference in current value, and the state of the third abnormality determination flag. [Figure 8] FIG. 8 is a time chart showing the establishment state of the abnormality detection condition, the operation state of the brake lever, and the difference in current value when the third abnormality is detected and the brake is adjusted. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] A vehicle 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an outline of the vehicle 1 according to the embodiment. The vehicle 1 is basically a vehicle that travels at a low speed. The vehicle 1 includes, for example, a senior car and an electric wheelchair.

[0013] The vehicle 1 includes a main body 2, wheels 3, a steering wheel 4, a brake lever 5, a mechanical brake 6 (hereinafter referred to as "brake 6"), a motor 7, an inverter 8, a battery 9, and a control device 10 (vehicle control device). The main body 2 is provided with a seat 2a on which a driver sits. The main body 2 is provided with an accelerator pedal 2b. Note that an accelerator lever may be provided on the steering wheel 4 instead of the accelerator pedal 2b.

[0014] In the following description, the side in front of the driver seated on the seat 2a will be referred to as the front, and the side opposite the front will be referred to as the rear. The right-hand side of the driver seated on the seat 2a will be referred to as the right side, and the left-hand side of the driver will be referred to as the left side. The vertical direction will be referred to as the down direction, and the side opposite the vertical direction will be referred to as the up direction.

[0015] The wheels 3 include front wheels 11 and rear wheels 12. The front wheels 11 are supported on a shaft extending in the left-right direction. The front wheels 11 include a left front wheel 11L provided on the left and a right front wheel 11R provided on the right. The rear wheels 12 are provided behind the front wheels 11. The rear wheels 12 include a left rear wheel 12L provided on the left and a right rear wheel 12R provided on the right. The left rear wheel 12L is supported on a shaft extending in the left-right direction. The right rear wheel 12R is supported on a shaft extending in the left-right direction.

[0016] The handlebars 4 are attached to the main body 2 via mounting parts that extend in the vertical direction. The handlebars 4 extend, for example, in the left-right direction and are gripped by the driver. By operating the handlebars 4, the steering angle of the front wheels 11 is changed.

[0017] The brake lever 5 is attached to the handlebar 4. When the brake lever 5 is operated, the brake 6 is actuated, and the brake 6 generates a braking force.

[0018] The brake 6 is provided on the rear wheel 12. Specifically, the brake 6 is provided on one of the two rear wheels 12. For example, the brake 6 is provided on the right rear wheel 12R. The brake 6 is not provided on the other rear wheel 12, for example, the left rear wheel 12L. The brake 6 is, for example, a disc brake or a drum brake. The brake 6 is actuated by the driver's operation of the brake lever 5 (brake operation). The brake 6 may also be provided on the left rear wheel 12L. In this case, the brake 6 is not provided on the right rear wheel 12R.

[0019] By providing the brake 6 on one of the rear wheels 12 (for example, the right rear wheel 12R) and not on the other rear wheel 12 (for example, the left rear wheel 12L), the vehicle 1 can reduce the number of parts and keep costs down.

[0020] The motors 7 are provided on the wheels 3. The motors 7 are provided on each of the rear wheels 12. That is, the motors 7 include a left motor 7L provided on the left rear wheel 12L and a right motor 7R provided on the right rear wheel 12R. The motors 7 generate driving force to rotate the rear wheels 12. The driving force generated by the motors 7 is transmitted to the rear wheels 12. The motors 7 generate driving force according to the amount of depression of the accelerator pedal 2b. When the accelerator pedal 2b is not depressed, the motor 7 does not generate driving force. When the amount of depression of the accelerator pedal 2b decreases while the vehicle is traveling, or when the accelerator pedal 2b is released while the vehicle is traveling, the motor 7 functions as a generator. When the motor 7 functions as a generator, regenerative braking is generated in the vehicle 1.

[0021] The inverter 8 generates an AC drive signal for driving the motor 7 and outputs the generated drive signal to the motor 7. The drive signal is generated based on an instruction signal transmitted from the control device 10. That is, the inverter 8 controls the motor 7 based on the instruction signal transmitted from the control device 10. An inverter 8 is provided for each of the left motor 7L and the right motor 7R. That is, the inverter 8 includes a left inverter 8L provided in the left motor 7L and a right inverter 8R provided in the right motor 7R.

[0022] The battery 9 supplies power to the motor 7. When the motor 7 functions as a generator, the battery 9 is charged by the power generated by the motor 7. The battery 9 is charged by being connected to an external power source. The battery 9 may be detachable from the vehicle 1.

[0023] As shown in Fig. 2, the control device 10 includes a controller 20 and a storage unit 21. Fig. 2 is a block diagram illustrating the control device 10 according to the embodiment.

[0024] The storage unit 21 is realized by a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, etc. The storage unit 21 stores various data, various programs, etc.

[0025] The controller 20 corresponds to a so-called processor. The controller 20 is realized by a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphical Processing Unit), or the like. The controller 20 executes a program according to an embodiment (not shown) stored in a storage unit 21, using a RAM as a work area. The controller 20 can also be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0026] A vehicle speed sensor 30, an accelerator sensor 31, a steering angle sensor 32, a brake sensor 33, a first current sensor 34, and a second current sensor 35 are connected to the controller 20. The controller 20 acquires signals output from the sensors 30-35.

[0027] The vehicle speed sensor 30 detects the vehicle speed of the vehicle 1. The vehicle speed sensor 30 outputs a signal indicating the detected vehicle speed to the controller 20. The accelerator sensor 31 detects the depression amount of the accelerator pedal 2b. The accelerator sensor 31 outputs a signal indicating the detected depression amount of the accelerator pedal 2b to the controller 20.

[0028] The steering angle sensor 32 detects the steering angle, which is the amount of operation of the steering wheel 4. The steering angle sensor 32 outputs a signal indicating the detected steering angle to the controller 20. The brake sensor 33 detects the amount of operation of the brake lever 5. The brake sensor 33 outputs a signal indicating the detected amount of operation of the brake lever 5 to the controller 20.

[0029] The first current sensor 34 detects the current value of the left motor 7L. The first current sensor 34 outputs a signal indicating the detected current value to the controller 20. The second current sensor 35 detects the current value of the right motor 7R. The second current sensor 35 outputs a signal indicating the detected current value to the controller 20.

[0030] The controller 20 generates an instruction signal based on the depression amount of the accelerator pedal 2b and transmits the generated instruction signal to the left inverter 8L and the right inverter 8R. Furthermore, the controller 20 detects an abnormality when an abnormality occurs in the brake 6. Specifically, the controller 20 detects an abnormality in the brake 6 by executing a first abnormality detection process and a second abnormality detection process.

[0031] The first abnormality detection process executed by the controller 20 will be described with reference to Fig. 3. Fig. 3 is a flowchart illustrating the first abnormality detection process according to the embodiment. For example, the controller 20 executes the first abnormality detection process at a preset first processing cycle.

[0032] The controller 20 determines whether or not the abnormality detection condition is met (S100). The controller 20 determines whether or not the running state of the vehicle 1 satisfies the abnormality detection condition. The running state of the vehicle 1 includes the vehicle speed and the steering angle. The abnormality detection condition is met when the vehicle 1 is running straight.

[0033] Specifically, when the vehicle speed is equal to or greater than a predetermined traveling speed and the steering angle is less than a predetermined steering angle, the controller 20 determines that the vehicle 1 is traveling straight and that the abnormality detection condition is met. In other words, the controller 20 determines that the abnormality detection condition is established. The predetermined traveling speed is a vehicle speed that is set in advance and is a vehicle speed at which it can be determined that the vehicle 1 is not stopped. The predetermined steering angle is a steering angle that is set in advance and is a steering angle at which it can be determined that the vehicle 1 is traveling straight.

[0034] If the vehicle speed is less than the predetermined traveling speed, the controller 20 determines that the vehicle 1 is not traveling and the abnormality detection condition is not satisfied. If the steering angle is equal to or greater than the predetermined steering angle, the controller 20 determines that the vehicle 1 is not traveling straight and the abnormality detection condition is not satisfied. In other words, the controller 20 determines that the abnormality detection condition is not established.

[0035] If the controller 20 determines that the abnormality detection condition is not met (S100: No), the controller 20 ends the current processing.

[0036] When the controller 20 determines that the abnormality detection condition is met (S100: Yes), the controller 20 determines whether the brake lever 5 is ON or not (S101). Specifically, the controller 20 determines whether the brake lever 5 is being operated or not. When the brake lever 5 is being operated, the controller 20 determines that the brake lever 5 is ON. When the brake lever 5 is not being operated, the controller 20 determines that the brake lever 5 is not ON, that is, the brake lever 5 is OFF. The controller 20 determines whether the brake lever 5 is ON or not based on the operation amount of the brake lever 5 output from the brake sensor 33. For example, when the operation amount of the brake lever 5 is equal to or greater than a predetermined operation amount set in advance, the controller 20 determines that the brake lever 5 is ON. When the operation amount of the brake lever 5 is less than the predetermined operation amount, the controller 20 determines that the brake lever 5 is not ON, that is, the brake lever 5 is OFF.

[0037] When the controller 20 determines that the brake lever 5 is not ON (S101: No), it counts up a first determination time (S102). The first determination time is the time during which the brake lever 5 is continuously OFF. The first determination time is reset when it is determined that the abnormality detection condition is not met (S100: No) or when it is determined that the brake lever 5 is ON (S101: Yes).

[0038] Next, the controller 20 determines whether a first predetermined time has elapsed (S103). The first predetermined time is a time set in advance. The first predetermined time is the time during which the current sensors 34, 35 can accurately detect the current value when the brake lever 5 is turned OFF. If the first determination time is less than the first predetermined time, the controller 20 determines that the first predetermined time has not elapsed. If the first determination time is equal to or greater than the first predetermined time, the controller 20 determines that the first predetermined time has elapsed.

[0039] When the controller 20 determines that the first predetermined time has not elapsed (S103: No), it ends the current processing.

[0040] When the controller 20 determines that the first predetermined time has elapsed (S103: Yes), it determines whether the difference in the current values ​​is equal to or greater than a first threshold value (S104). The first threshold value is a preset value. The first threshold value is a value at which it is possible to determine that the brake 6 is operating. The controller 20 calculates the difference between the current value of the right motor 7R detected by the second current sensor 35 and the current value of the left motor 7L detected by the first current sensor 34. In other words, the difference in the current values ​​is the difference between the current value of the right motor 7R and the current value of the left motor 7L.

[0041] When the brake 6 is not operating, the current value detected by the second current sensor 35 and the current value detected by the first current sensor 34 are approximately the same value, and therefore the difference in current value is small. When the brake 6 is not operating, the difference in current value is close to zero.

[0042] When the brake 6 is applied, the right motor 7R drives the right rear wheel 12R against the braking force of the brake 6, and the current value detected by the second current sensor 35 becomes larger than the current value detected by the first current sensor 34. Therefore, when the brake 6 is applied, the difference in the current values ​​becomes larger than the difference in the current values ​​when the brake 6 is not applied. When the brake 6 is applied, the difference in the current values ​​becomes equal to or greater than the first threshold value.

[0043] When the controller 20 determines that the difference in the current values ​​is less than the first threshold value (S104: No), the controller 20 ends the current processing.

[0044] When the controller 20 determines that the difference in the current values ​​is equal to or greater than the first threshold value (S104: Yes), it detects a first abnormality (S105). The first abnormality is a state in which braking force is generated by the brake 6 on the right rear wheel 12R even though the brake lever 5 is OFF. In other words, the first abnormality is a state in which the brake 6 is operating abnormally and is always ON.

[0045] For example, in response to the detection of the first abnormality, the controller 20 issues a warning to the driver. The controller 20 turns on a warning light to notify the driver that the first abnormality has been detected. The controller 20 also sets a first abnormality detection flag corresponding to the detection of the first abnormality. For example, the controller 20 sets the first abnormality detection flag to "1."

[0046] In this way, the controller 20 detects the first abnormality when the abnormality detection condition is met (S100: Yes) and the difference in the current value is equal to or greater than the first threshold value when the brake 6 is not operated (S101: No). That is, the controller 20 detects the first abnormality when the vehicle 1 is traveling straight and the difference in the current value is equal to or greater than the first threshold value when the brake 6 is not operated.

[0047] This allows the controller 20 to detect the first abnormality in which the brake 6 operates abnormally, even if the brake 6 is provided on one of the rear wheels 12, for example, the right rear wheel 12R.

[0048] When the controller 20 determines that the brake lever 5 is ON (S101: Yes), it counts up a second determination time (S106). The second determination time is the time during which the brake lever 5 is continuously ON. The second determination time is reset when it is determined that the abnormality detection condition is not met (S100: No) or when it is determined that the brake lever 5 is OFF (S101: No).

[0049] Next, the controller 20 determines whether a second predetermined time has elapsed (S107). The second predetermined time is a time set in advance. The second predetermined time is the time during which, when the brake lever 5 is turned ON, a difference occurs between the current values ​​detected by the current sensors 34, 35. If the second determination time is less than the second predetermined time, the controller 20 determines that the second predetermined time has not elapsed. If the second determination time is equal to or greater than the second predetermined time, the controller 20 determines that the second predetermined time has elapsed.

[0050] If the controller 20 determines that the second predetermined time has not elapsed (S107: No), it ends the current processing.

[0051] When the controller 20 determines that the second predetermined time has elapsed (S107: Yes), it determines whether the difference in the current values ​​is less than a second threshold value (S108). The controller 20 calculates the difference between the current value of the right motor 7R detected by the second current sensor 35 and the current value of the left motor 7L detected by the first current sensor 34. The second threshold value is a preset value. The second threshold value is a value at which it can be determined that the brake 6 is not operating. The second threshold value is, for example, smaller than the first threshold value. The second threshold value may be the same value as the first threshold value.

[0052] When the controller 20 determines that the difference in the current values ​​is less than the second threshold value (S108: Yes), it detects a second abnormality (S109). The second abnormality is a state in which the brake 6 does not apply braking force to the right rear wheel 12R even though the brake lever 5 is ON. In other words, the second abnormality is a state in which the brake 6 is not operating and is always OFF. For example, the second abnormality is a break in the brake wire.

[0053] For example, the controller 20 issues a warning to the driver in response to the detection of the second abnormality. The controller 20 turns on a warning light to notify the driver that the second abnormality has been detected. The controller 20 may notify the driver that the second abnormality has been detected by a method different from that used for notifying the driver of the first abnormality. For example, the controller 20 may turn on a warning light different from the warning light used to notify the driver of the first abnormality. The controller 20 sets a second abnormality detection flag corresponding to the detection of the second abnormality. For example, the controller 20 sets the second abnormality detection flag to "1".

[0054] In this way, the controller 20 detects the second abnormality when the abnormality detection condition is met (S100: Yes) and the difference in the current value is less than the second threshold value (S108: Yes) while the brake 6 is being operated (S101: Yes). In other words, the controller 20 detects the second abnormality when the vehicle 1 is traveling straight and the difference in the current value is less than the second threshold value while the brake 6 is being operated.

[0055] As a result, even if the brake 6 is provided on one of the rear wheels 12, for example, the right rear wheel 12R, the controller 20 can detect the second abnormality in which the brake 6 does not operate.

[0056] When the controller 20 determines that the difference in the current values ​​is equal to or greater than the second threshold (S108: No), it determines whether the difference in the current values ​​is equal to or less than a third threshold (S110). The third threshold is a preset value. The third threshold is greater than the second threshold. The third threshold is a value that allows determination that the brake 6 is operating but the operation of the brake 6 is not normal. The operation of the brake 6 is not normal when the braking force of the brake 6 is not normal due to poor adjustment or deterioration of the brake 6. When the brake 6 is poorly adjusted or deteriorated, the braking force of the brake 6 becomes smaller than the normal braking force. Therefore, the current value of the right motor 7R detected by the second current sensor 35 becomes smaller than the normal current value. Therefore, when the brake 6 is poorly adjusted or deteriorated, the difference in the current values ​​becomes smaller than the normal current value.

[0057] When the controller 20 determines that the difference in the current values ​​is equal to or smaller than the third threshold value (S110: Yes), the controller 20 detects a third abnormality (S111). The third abnormality is a state in which the brake lever 5 is ON and the brake 6 is operating, but the operation of the brake 6 is not normal.

[0058] For example, the controller 20 issues a warning to the driver in response to the detection of the third abnormality. The controller 20 turns on a warning light to notify the driver that the third abnormality has been detected. The controller 20 may notify the driver that the third abnormality has been detected by a method different from that used for the first abnormality and the second abnormality. For example, the controller 20 may turn on a warning light different from the warning light that notifies the first abnormality or the second abnormality. Note that the controller 20 sets a third abnormality detection flag corresponding to the detection of the third abnormality. For example, the controller 20 sets the third abnormality detection flag to "1."

[0059] In this way, the controller 20 detects a third abnormality when the abnormality detection condition is met (S100: Yes) and the difference in current value when the brake 6 is operated (S101: Yes) is greater than or equal to the second threshold value (S108: No) and less than or equal to the third threshold value (S110: Yes).

[0060] This allows the controller 20 to detect the third abnormality in which the brake 6 does not operate normally, even if the brake 6 is provided on one of the rear wheels 12, for example, the right rear wheel 12R.

[0061] When the controller 20 determines that the difference in the current values ​​is greater than the third threshold value (S110: No), the controller 20 determines that the brake 6 is normal (S112).

[0062] The controller 20 may execute the first abnormality detection process when there is no abnormality in the motor 7, the inverter 8, etc. Abnormalities in the motor 7, the inverter 8, etc. include, for example, an abnormal rotation speed of the motor 7, an overvoltage error, an error in each sensor, and an error in the controller 20. By executing the first abnormality detection process when there is no abnormality in the motor 7, the inverter 8, etc., the controller 20 can accurately determine whether or not an abnormality has occurred in the brake 6.

[0063] Next, the second abnormality detection process executed by the controller 20 will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating the second abnormality detection process according to this embodiment. The second abnormality detection process is performed after the brakes 6 have been adjusted by a dealer or the like. For example, the second abnormality detection process is performed after the dealer or the like confirms that the third abnormality detection flag is "1" and the brakes 6 have been adjusted by the dealer or the like. For example, the controller 20 executes the second abnormality detection process at a preset second processing cycle.

[0064] The controller 20 determines whether or not the vehicle is in the maintenance mode (S200). The maintenance mode is a mode that is set by a dealer or the like when performing maintenance on the vehicle 1. The maintenance mode is set, for example, by connecting an external device to the control device 10 and operating the external device.

[0065] If the controller 20 determines that the system is not in the maintenance mode (S200: No), it ends this processing. If the controller 20 determines that the system is in the maintenance mode (S200: Yes), it determines whether or not an abnormality detection condition is met (S201). The abnormality detection condition is the same as the abnormality detection condition in the first abnormality detection processing.

[0066] If the abnormality detection condition is not met (S201: No), the controller 20 ends the current process.

[0067] If the abnormality detection condition is met (S201: Yes), the controller 20 determines whether the brake lever 5 is ON (S202). The method for determining whether the brake lever 5 is ON is the same as the method for determining in the first abnormality detection process.

[0068] If the controller 20 determines that the brake lever 5 is not ON (S202: No), the controller 20 ends the current processing.

[0069] When the controller 20 determines that the brake lever 5 is ON (S202: Yes), it counts up a third determination time (S203). The third determination time is the time during which the brake lever 5 is continuously ON. The third determination time is reset when it is determined that the maintenance mode is not in effect (S200: No), when it is determined that the abnormality detection condition is not satisfied (S201: No), or when it is determined that the brake lever 5 is OFF (S202: No).

[0070] Next, the controller 20 determines whether a third predetermined time has elapsed (S204). The third predetermined time is a time set in advance. For example, the third predetermined time is the time during which, when the brake lever 5 is turned ON, a difference occurs in the current values ​​detected by the current sensors 34, 35 as a result of the brake lever 5 being turned ON. The third predetermined time may be the same as the second predetermined time. If the third determination time is less than the third predetermined time, the controller 20 determines that the third predetermined time has not elapsed. If the third determination time is equal to or greater than the third predetermined time, the controller 20 determines that the third predetermined time has elapsed.

[0071] If the controller 20 determines that the third predetermined time has not elapsed (S204: No), it ends this processing. If the controller 20 determines that the third predetermined time has elapsed (S204: Yes), it determines whether the difference in the current values ​​is equal to or less than a fourth threshold (S205). The controller 20 calculates the difference between the current value of the right motor 7R detected by the second current sensor 35 and the current value of the left motor 7L detected by the first current sensor 34. The fourth threshold is a preset value. The fourth threshold is a value that can determine that the brake 6 is operating but has deteriorated. When the second abnormality detection processing is executed, the brake 6 is being adjusted. Therefore, if the difference in the current values ​​is equal to or less than the fourth threshold, it is not due to poor adjustment of the brake 6 but rather due to deterioration of the brake 6. The fourth threshold is equal to or greater than the third threshold. For example, the fourth threshold is the same value as the third threshold.

[0072] If the difference in the current values ​​is greater than the fourth threshold value (S205: No), the controller 20 determines that the brake 6 is operating normally due to the adjustment of the brake 6 (S206).

[0073] If the difference in the current values ​​is equal to or less than the fourth threshold value (S205: Yes), the controller 20 detects deterioration of the brake 6 (S207). For example, the controller 20 issues a warning to an operator in response to the detection of deterioration of the brake 6. The controller 20 turns on a warning light to notify the operator that deterioration of the brake 6 has been detected.

[0074] In this way, the controller 20 detects deterioration of the brake 6 when the abnormality detection condition is met (S201: Yes) and the difference in current value when the brake 6 is operated (S202: Yes) is less than or equal to the fourth threshold value (S205: Yes).

[0075] As a result, the worker disassembles the brake 6 and replaces the part. By performing the second abnormality detection process, if replacement of a part of the brake 6 is necessary, a warning is issued and the part of the brake 6 is replaced. In other words, if deterioration of the brake 6 is detected by the second abnormality detection process, in other words, if deterioration of the brake 6 is identified, the worker can disassemble the brake 6 and replace the part. Therefore, the controller 20 can suppress unnecessary disassembly of the brake 6.

[0076] Next, the difference in current value when the first abnormality occurs will be described with reference to Fig. 5. Fig. 5 is a time chart showing the establishment state of the abnormality detection condition when the first abnormality occurs, the operation state of the brake lever 5, the difference in current value, and the state of the first abnormality determination flag. The first abnormality determination flag is initially set to "0".

[0077] At time t0, the abnormality detection condition is met. At time t0, counting of the first determination time period starts. Note that the brake lever 5 has not been operated since before time t0, and the brake lever 5 is in the OFF position.

[0078] At time t1, when the first determination time reaches the first predetermined time, the difference in the current values ​​is calculated. Because a first abnormality has occurred, the difference in the current values ​​is equal to or greater than the first threshold. Therefore, at time t1, the first abnormality is detected, and the first abnormality determination flag is set to "1."

[0079] Next, the difference in current value when the second abnormality occurs will be described with reference to Fig. 6. Fig. 6 is a time chart showing the establishment state of the abnormality detection condition when the second abnormality occurs, the operation state of the brake lever 5, the difference in current value, and the state of the second abnormality determination flag. The second abnormality determination flag is initially set to "0."

[0080] At time t0, the abnormality detection condition is met. Note that the brake lever 5 has not been operated since before time t0, and is in the OFF position.

[0081] At time t11, the brake lever 5 is operated to turn ON the brake lever 5. At time t11, counting of the second determination time period starts.

[0082] At time t12, when the second determination time reaches the second predetermined time, the difference in the current values ​​is calculated. Because a second abnormality has occurred, the difference in the current values ​​is less than the second threshold. Therefore, at time t12, the second abnormality is detected, and the second abnormality determination flag is set to "1."

[0083] Next, the difference in current value when the third abnormality occurs will be described with reference to Fig. 7. Fig. 7 is a time chart showing the establishment state of the abnormality detection condition when the third abnormality occurs, the operation state of the brake lever 5, the difference in current value, and the state of the third abnormality determination flag. The third abnormality determination flag is initially set to "0."

[0084] At time t0, the abnormality detection condition is met. Note that the brake lever 5 has not been operated since before time t0, and is in the OFF position.

[0085] At time t21, the brake lever 5 is operated to turn ON the brake lever 5. At time t21, counting of the third determination time period starts.

[0086] At time t22, when the second determination time reaches the second predetermined time, the difference in the current values ​​is calculated. Here, because the brake lever 5 is ON at time t21, the difference in the current values ​​is equal to or greater than the second threshold. Also, because a third abnormality has occurred, the difference in the current values ​​is equal to or less than the third threshold. Therefore, at time t22, the third abnormality is detected, and the third abnormality determination flag is set to "1."

[0087] Next, the difference in current value when the brake 6 is deteriorated will be described with reference to Fig. 8. Fig. 8 is a time chart showing the establishment state of the abnormality detection condition, the operation state of the brake lever 5, and the difference in current value when the third abnormality is detected and the brake 6 is adjusted. In this case, the maintenance mode is set.

[0088] At time t0, the abnormality detection condition is met. Note that the brake lever 5 has not been operated since before time t0, and is in the OFF position.

[0089] At time t31, the brake lever 5 is operated to turn ON the brake lever 5. At time t31, counting of the third determination time period starts.

[0090] At time t32, when the third determination time reaches the third predetermined time, the difference in the current values ​​is calculated. Because deterioration of the brake 6 has occurred, the difference in the current values ​​is equal to or smaller than the fourth threshold value. Therefore, deterioration of the brake 6 is detected at time t32.

[0091] In the above embodiment, an example in which a motor 7 is provided for each of the rear wheels 12 has been described, but the present invention is not limited to this. The vehicle 1 may also be provided with a motor 7 for each of the front wheels 11. Furthermore, the vehicle 1 may also be provided with a motor 7 for each of the front wheels 11 and the rear wheels 12. In other words, the vehicle 1 may be a four-wheel drive vehicle. If the vehicle 1 is a four-wheel drive vehicle, an abnormality in the brake 6 may be detected using the difference between the current value in the right motor 7R of the right rear wheel 12R to which the brake 6 is provided and the current value in at least one of the motors 7 of the other wheels 3. For example, an abnormality in the brake 6 may be detected using the difference between the current value in the right motor 7R of the right rear wheel 12R and the current value in the motor 7 of the right front wheel 11R.

[0092] Furthermore, an abnormality in the brake 6 may be detected based on the rotation speed and torque of the motor 7. Furthermore, the abnormality detection condition may be satisfied when the acceleration of the vehicle 1 is equal to or less than a predetermined acceleration. Furthermore, the abnormality detection condition may be satisfied when the deceleration of the vehicle 1 is equal to or less than a predetermined deceleration. The predetermined acceleration and the predetermined deceleration are within a preset range. The predetermined acceleration and the predetermined deceleration are, for example, values ​​that can be used to determine whether the vehicle 1 is suddenly accelerating or decelerating.

[0093] Further advantages and modifications will readily occur to those skilled in the art. Therefore, 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 their equivalents. [Explanation of symbols]

[0094] 1 vehicle 3 wheels 4 Handle 5 Brake lever 6 Brake (mechanical brake) 7 Motor 10 Control device (vehicle control device) 12 rear wheels 20 Controller 30 Vehicle speed sensor 31 Accelerator sensor 32 Steering angle sensor 33 Brake sensor 34 First current sensor 35 Second current sensor

Claims

1. A vehicle control device mounted on a vehicle that is driven by motors provided on two wheels, respectively, and in which a mechanical brake provided on one wheel is actuated by a brake operation by a driver, a controller that detects an abnormality in the mechanical brake; The controller detects a first abnormality in which the mechanical brake is operating abnormally when the difference in current values ​​of each motor is equal to or greater than a first threshold value while the vehicle is traveling straight and the mechanical brake is not being operated.

2. A vehicle control device mounted on a vehicle that is driven by motors provided on two wheels, respectively, and in which a mechanical brake provided on one wheel is actuated by a brake operation by a driver, a controller that detects an abnormality in the mechanical brake; The controller detects a second abnormality in which the mechanical brake is not operating when the difference in current values ​​of each motor when the vehicle is traveling straight and the mechanical brake is operated is less than a second threshold value.

3. The vehicle control device according to claim 1 or 2, wherein the mechanical brake is not provided on the other of the two wheels.

4. the controller detects a third abnormality, which is a poor adjustment of the mechanical brake or deterioration of the mechanical brake, when the difference in the current values ​​when the vehicle is traveling straight and the mechanical brake is operated is equal to or greater than the second threshold value and equal to or less than a third threshold value; The vehicle control device according to claim 2 , wherein the third threshold value is greater than the second threshold value.

5. the controller detects deterioration of the mechanical brake when the difference in the current values ​​is equal to or less than a fourth threshold value in a state in which the mechanical brake is adjusted, the vehicle is traveling straight, and the mechanical brake is operated; The vehicle control device according to claim 4 , wherein the fourth threshold value is equal to or greater than the third threshold value.

6. A vehicle comprising the vehicle control device according to claim 1 or 2.

7. An abnormality detection method for detecting an abnormality in a vehicle that is driven by a motor provided on each of two wheels and in which a mechanical brake provided on one of the wheels is activated by a brake operation by a driver, comprising: An abnormality detection method that detects a first abnormality in which the mechanical brake is operating abnormally when the difference in current values ​​of each motor is equal to or greater than a first threshold value when the vehicle is traveling straight and the mechanical brake is not being operated.

8. An abnormality detection method for detecting an abnormality in a vehicle that is driven by a motor provided on each of two wheels and in which a mechanical brake provided on one of the wheels is activated by a brake operation by a driver, comprising: An abnormality detection method that detects a second abnormality in which the mechanical brake is not operating when the difference in current values ​​of each motor is less than a second threshold value while the vehicle is traveling straight and the mechanical brake is operated.

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