Motor-operated vehicle

Abstract

To provide a motor-operated vehicle which appropriately protect, when prediction of drive power outputted from an electric motor is possible, a power storage device.SOLUTION: A motor-operated vehicle includes a control unit which controls an electric motor that outputs traveling power, a brake device, and a steering device so that the vehicle travels by a driving mode selected by a driver from an automatic operation mode and a manual operation mode based on information from a periphery recognition device. The control unit alleviates, during traveling at the automatic operation mode, limitation of feedback control regarding input / output of a power storage device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to electric vehicles, and more particularly to electric vehicles capable of autonomous driving. [Background technology]

[0002] Conventionally, for this type of electric vehicle, a system has been proposed in which current feedback control is performed using the allowable current of the power storage device as a control threshold in order to protect the power storage device that exchanges power with the electric motor for driving (see, for example, Patent Document 1). This makes it possible to more appropriately protect the power storage device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-106459 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned electric vehicle, when the driving force output from the electric motor for driving can be predicted, it is also possible to predict that the input / output of the power storage device will temporarily increase. Therefore, if the power storage device is protected in the same way as when the driving force is unpredictable, the power storage device may be overprotected, and may not be able to perform sufficiently.

[0005] The electric vehicle of the present disclosure has a primary object to more appropriately protect the power storage device when the driving force output from the electric motor is predictable. [Means for solving the problem]

[0006] The electric vehicle of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The electric vehicle disclosed herein is an electric vehicle equipped with an electric motor that outputs power for driving, a storage device that exchanges power with the electric motor, a brake device that applies braking force to the vehicle, a steering device that performs steering, a surrounding recognition device that acquires information about the vehicle's surroundings, and a control device that uses information from the surrounding recognition device to control the electric motor, the brake device, and the steering device so that the vehicle drives in a driving mode selected by the driver from an autonomous driving mode or a manual driving mode, and is characterized in that the control device relaxes restrictions in feedback control of the input and output of the storage device while the vehicle is driving in the autonomous driving mode.

[0008] The electric vehicle disclosed herein includes an electric motor that outputs power for driving, a power storage device that exchanges power with the electric motor, a brake device that applies braking force to the vehicle, a steering device that performs steering, a surroundings recognition device that acquires information about the vehicle's surroundings, and a control device that controls the electric motor, the brake device, and the steering device using information from the surroundings recognition device to drive the vehicle in a driving mode selected by the driver from an autonomous driving mode or a manual driving mode. The control device relaxes limitations in feedback control of the input / output of the power storage device while the vehicle is driving in the autonomous driving mode. When driving in the autonomous driving mode, it becomes possible to predict the driving force output from the electric motor that outputs power for driving. When the driving force can be predicted in this way, it is also possible to predict the input / output from the power storage device, making it possible to prevent cases where the limitations in feedback control of the input / output of the power storage device are excessively exceeded. Therefore, when driving in the autonomous driving mode, it is possible to more appropriately protect the power storage device even if limitations in feedback control of the input / output of the power storage device are relaxed. As a result, the power storage device can be protected more appropriately when the driving force output from the electric motor can be predicted. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing an outline of the configuration of an electric vehicle 20 according to an embodiment of the present disclosure. [Figure 2]4 is a flowchart showing an example of a feedback control threshold setting process executed by the main ECU 40. [Figure 3] 10 is an explanatory diagram showing an example of the relationship between the rated voltage Vstnd of the battery 25, the threshold value Vref of the voltage feedback control, and the voltage lower limit value Vmin. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 as one embodiment of the present disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a motor 22, a battery 25, a brake device (braking device) 24, a steering device 34, and an electronic control unit (hereinafter referred to as "main ECU") 30.

[0011] The motor 22 is configured as, for example, a three-phase AC motor and includes a rotor with a permanent magnet embedded in the rotor core and a stator with a three-phase coil wound around the stator core. The rotor of the motor 22 is connected to a drive shaft 26, which is connected to drive wheels 28a and 28b via a differential gear 27. The motor 22 is driven by a motor electronic control unit (hereinafter referred to as the "motor ECU") 23 controlling the switching of switching elements in an inverter 24. The inverter 24 is connected to a battery 25 via a power line and includes a well-known inverter circuit having six transistors as switching elements and six diodes connected in parallel to each of the six transistors. The motor ECU 23 includes a microcomputer (not shown) having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The motor ECU 23 receives inputs such as phase currents from a current sensor that detects the phase currents of the three-phase AC power applied to the motor 22 from the inverter 24, and a rotational position from a position detection sensor that detects the rotational position of the motor. The motor ECU 23 outputs a control signal for switching the switching elements of the inverter 24. The motor ECU 23 communicates with the main ECU 40 via a communication port, receives torque commands calculated by the main ECU 40, and transmits data indicating the state of the motor 22 and the like to the main ECU 40.

[0012] The battery 25 is configured as a lithium ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the inverter 24 via a power line.

[0013] The brake device 30 is configured as a well-known hydraulically driven brake device and is configured to apply braking forces resulting from the brake depression force applied by depressing the brake pedal 58 and braking forces resulting from hydraulic pressure adjustment to the drive wheels 28a, 28b and the driven wheels 28c, 28d. The brake device 30 is controlled and driven by a brake electronic control unit (hereinafter referred to as "brake ECU") 32. Although not shown, the brake ECU 32 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. The brake ECU 32 controls the braking forces resulting from the brake depression force applied by the brake device 30 and braking forces resulting from hydraulic pressure adjustment. The brake ECU 32 communicates with the main ECU 40 via the communication port.

[0014] The steering device 34 is mechanically connected to a steering wheel (not shown) and the drive wheels 28a, 28b via a steering shaft, and is equipped with a steering actuator. The steering device 34 steers the drive wheels 28a, 28b based on the driver's operation, and also steers the drive wheels 28a, 28b by driving the actuator based on a steering signal from the main ECU 40.

[0015] The main ECU 40 includes a microcomputer having a CPU 41, ROM 42, RAM 43, flash memory 44, and input / output and communication ports (not shown). Signals from various sensors are input to the main ECU 40 via the input ports. Examples of signals input to the main ECU 40 include an ignition signal from an ignition switch 50, a vehicle speed V from a vehicle speed sensor 51, wheel speeds from wheel speed sensors 52, an acceleration α from an acceleration sensor 53, a yaw rate Yr from a yaw rate sensor 54, and a road gradient θr from a gradient sensor 55. Other signals include an accelerator opening Acc from an accelerator pedal position sensor 57 that detects the amount of depression of an accelerator pedal 56, and a brake pedal position BP from a brake pedal position sensor 59 that detects the amount of depression of a brake pedal 58. Another example of an on / off signal from the air conditioning unit 74 is also included.

[0016] Various control signals are output from the main ECU 40 via the output port. Examples of control signals output from the main ECU 40 include a control signal to the steering device 34, a display control signal to the display device 70, a communication control signal to the communication device 72, and an air conditioning control signal to the air conditioning device 74. As described above, the main ECU 40 communicates with the motor ECU 23, the brake ECU 32, and the like via the communication port. The main ECU 40 also communicates with a shift electronic control unit (hereinafter referred to as "shift ECU") 60, a periphery recognition electronic control unit (hereinafter referred to as "periphery recognition ECU") 65, and a navigation device 80 via the communication port.

[0017] Although not shown, the shift ECU 60 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. A shift position signal from a shift position sensor 62 that detects the operating position of a shift lever 61 is input to the shift ECU 60 via an input port. The shift positions include a parking position (P range), a neutral position (N range), a drive position (D range), and a reverse position (R range). The shift ECU 60 is connected to the main ECU 40 and a periphery recognition ECU 65 via a communication port, and sets the shift position based on the shift position signal from the shift position sensor 62 and a control signal from the periphery recognition ECU 65, and transmits the set shift position to the main ECU 40.

[0018] Although not shown, the periphery recognition ECU 65 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Various signals are input to the periphery recognition ECU 65 via the input ports. Examples of signals input to the periphery recognition ECU 65 include signals indicating information about the vehicle and its surroundings from the periphery recognition device 66 (e.g., inter-vehicle distances D1 and D2 between the vehicle and other vehicles ahead and behind it, and the vehicle's position in the lane on the road surface), and an automatic driving mode signal from the automatic driving switch 67. Examples of the periphery recognition device 66 include a camera, millimeter-wave radar, quasi-millimeter-wave radar, infrared laser radar, and sonar. The automatic driving switch 67 is a switch that switches between an automatic driving mode in which driving operations are performed automatically and a manual driving mode in which driving operations are performed by the driver. As described above, the periphery recognition ECU 65 communicates with the main ECU 40 and the shift ECU 60 via the communication ports.

[0019] The navigation device 80 includes a main body 82 with a built-in control unit, a GPS antenna 84 that receives information about the current location of the vehicle, and a display 86. The control unit of the main body 82 has a storage medium (e.g., a hard disk or SSD) that stores map information and the like, an input / output port, and a communication port. The map information stores service information (e.g., tourist information, parking lots, etc.) and road information for each driving section (e.g., between traffic lights and between intersections) as a database. The road information includes distance information, road width information, number of lanes information, area information (urban or suburban), type information (general road or expressway), gradient information, legal speed limit, number of traffic lights, turning radius of each curve, etc. The display 86 displays various information such as information about the current location of the vehicle and the planned route to the destination, and is configured as a touch panel display that allows the user to input various instructions. When a destination is set by a user operating the display 86, the main body 82 of the navigation device 80 sets a planned driving route from the current location of the vehicle to the destination based on map information stored in the main body 82 and the current location and destination of the vehicle obtained from the GPS antenna 84, and displays the set planned driving route on the display 86 to provide route guidance.

[0020] Next, a description will be given of the operation of the electric vehicle 20 of this embodiment configured as described above, particularly the operation when setting a feedback control threshold value for the input / output of the battery 25. Fig. 2 is a flowchart showing an example of a feedback control threshold value setting process executed by the main ECU 40. This process is repeatedly executed at predetermined time intervals.

[0021] When the feedback control threshold setting process is executed, the main ECU 40 determines whether the driving mode is the automatic driving mode or the manual driving mode (step S100). If it is determined that the driving mode is the manual driving mode, a normal threshold value Vref1 is set as the threshold value for feedback control of the voltage of the battery 2 (step S130), and this process ends. FIG. 3 is an explanatory diagram showing an example of the relationship between the rated voltage Vstnd of the battery 25, the threshold value Vref for voltage feedback control, and the voltage lower limit value Vmin. In the diagram, the solid line indicates the rated voltage Vstnd, the dashed line indicates the voltage lower limit value Vmin, the one-dot chain line indicates the normal threshold value Vref1, and the two-dot chain line indicates the threshold value Vref2 in the automatic driving mode. Here, the voltage feedback control is a control that adjusts the input / output power of the battery 25 toward the rated voltage Vstnd according to the difference between the voltage and the rated voltage Vstnd when the voltage falls below a threshold value.

[0022] If it is determined in step S100 that the driving mode is the automatic driving mode, it is determined whether the driving force output from the motor 22 is predictable (step S110). For example, when a driving route is set and the vehicle is being driven automatically, the driving force is predictable because the vehicle is driven automatically based on information for each segment of the driving route. If it is determined that the driving force output from the motor 22 is not predictable, a normal threshold value Vref1 is set as the threshold for feedback control of the voltage of the battery 2 (step S130), and the process ends. On the other hand, if it is determined that the driving force output from the motor 22 is predictable, a threshold value Vref2 that is less restrictive than the normal threshold value Vref1 is set as the threshold for feedback control of the voltage of the battery 2 (step S120), and the process ends. 3, when the driving mode is the automatic driving mode and the driving force output from the motor 22 is predictable, the driving force of the motor 22 is predictable, so that even if a threshold value Vref2 that is smaller (a more relaxed restriction) than the normal threshold value Vref1 is set as the threshold value for feedback control of the voltage of the battery 2 and voltage feedback control is not executed until the voltage Vb of the battery 25 becomes equal to or lower than the threshold value Vref2, the voltage of the battery 25 can be prevented from falling below the lower voltage limit Vmin. As a result, the battery 25 can be protected more appropriately.

[0023] In the electric vehicle 20 of the embodiment described above, when the driving mode is the autonomous driving mode and the driving force output from the motor 22 is predictable, the driving force of the motor 22 is predictable, so that even if a threshold value Vref2 that is smaller (has a more relaxed restriction) than the normal threshold value Vref1 is set as the threshold value for feedback control of the voltage of the battery 25 and voltage feedback control is not executed until the voltage Vb of the battery 25 becomes equal to or lower than the threshold value Vref2, the voltage of the battery 25 can be prevented from falling below the lower voltage limit Vmin. As a result, the battery 25 can be more appropriately protected.

[0024] In the electric vehicle 20 of the embodiment, the motor ECU 23 is used to control the motor 22, and the brake ECU 32 is used to control the brake device 30. However, all or part of the functions of the motor ECU 23 and the brake ECU 32 may be performed by the main ECU 40.

[0025] The embodiment has been described using the configuration of an automatically driven electric vehicle 20 equipped with a motor 22 and a battery 25, but the configuration may also be that of a hybrid vehicle or a fuel cell vehicle, as long as the vehicle is automatically driven and equipped with a motor and a battery for driving.

[0026] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section will be explained below. In the embodiment, the motor 22 corresponds to the "electric motor," the battery 25 corresponds to the "power storage device," the brake device 30 corresponds to the "brake device," the steering device 34 corresponds to the "steering device," the surrounding recognition device 66 corresponds to the "surrounding recognition device," and the motor ECU 23, the brake ECU 32, the main ECU 40, etc. correspond to the "control device."

[0027] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0028] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment in any way, and it goes without saying that the present invention can be carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0029] The present invention can be used in the electric vehicle manufacturing industry and the like. [Explanation of symbols]

[0030] 20 Electric vehicle, 22 Motor, 30 Brake device, 34 Steering device, 40 Main electronic control unit (main ECU), 66 Surrounding recognition device, 67 Automatic driving switch.

Claims

[Claim 1] An electric vehicle comprising: an electric motor that outputs power for driving; an electricity storage device that exchanges electric power with the electric motor; a brake device that applies braking force to the vehicle; a steering device that performs steering; a surrounding recognition device that acquires information about the surroundings of the vehicle; and a control device that uses information from the surrounding recognition device to control the electric motor, the brake device, and the steering device so that the vehicle runs in a driving mode selected by a driver from an automatic driving mode or a manual driving mode, The control device relaxes restrictions on feedback control of input / output of the power storage device while the vehicle is traveling in the autonomous driving mode. An electric vehicle characterized by:

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