Vehicle control device

Abstract

To provide a control device of a vehicle capable of facilitating drift traveling.SOLUTION: The control device 10 can independently control the braking / driving forces of the front wheels 2a, 2b and the rear wheels 2c, 2d. The control device 10 controls the braking / driving forces of the front wheels 2a, 2b so as to keep the slip ratios of the front wheels 2a, 2b constant in the state where the drift driving intention of the driver is detected. As a result, the occurrence of slip of the front wheels 2a and 2b can be suppressed, so that it is possible to control the car 1 so as to suppress understeering as well and to facilitate drift running.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent document 1 discloses a method in which, when drift mode is selected and the vehicle is entering a corner and the power is on, the controller (vehicle control device) reduces the torque distributed to the front wheels of the AWD compared to when the vehicle is not in drift mode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-194060 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional method described in Patent Document 1 and the like, if the front wheels slip when the drift mode is selected, understeer occurs, which can make drifting difficult. An object of the present disclosure is to provide a vehicle control device that makes it easier to perform drifting. [Means for solving the problem]

[0005] A vehicle control device according to one aspect of an embodiment of the present invention is a vehicle control device that can independently control the braking and driving forces of the front and rear wheels, and when it detects the user's intention to drift, it controls the braking and driving forces of the front wheels so as to maintain a constant slip ratio of the front wheels. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a vehicle control device that makes it easier to perform drifting. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating a general configuration of an example of a vehicle equipped with a control device according to an embodiment; [Figure 2] 1 is a flowchart of front wheel slip suppression control according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0009] 1 is a schematic diagram showing a general configuration of an example of a vehicle 1 equipped with a control device 10 according to an embodiment. In FIG. 1, the left side of the drawing is the front direction of the vehicle 1, and the right side of the drawing is the rear direction of the vehicle 1.

[0010] The vehicle 1 is an electric vehicle that has a drive motor as a drive source and runs using torque output from the drive motor. Note that the vehicle 1 shown in Fig. 1 is an example of a vehicle equipped with the control device 10 according to the present embodiment, and the configuration of the vehicle is not limited to the example shown in Fig. 1.

[0011] As shown in FIG. 1, the vehicle 1 includes front wheels 2a, 2b, rear wheels 2c, 2d, a front differential 3f, a rear differential 3r, a front wheel drive motor 4f, a rear wheel drive motor 4r, inverters 5f, 5r, a battery 6, a front wheel motor rotation speed sensor 7f, a rear wheel motor rotation speed sensor 7r, and a control device 10.

[0012] Hereinafter, when there is no need to distinguish between the front wheels 2a, 2b, rear wheels 2c, and rear wheels 2d, they will also be simply referred to as wheels 2. When there is no need to distinguish between the front wheel drive motor 4f and the rear wheel drive motor 4r, they will also be simply referred to as drive motor 4. When there is no need to distinguish between the inverter 5f and the inverter 5r, they will also be simply referred to as inverter 5. When there is no need to distinguish between the front wheel motor rotation speed sensor 7f and the rear wheel motor rotation speed sensor 7r, they will also be simply referred to as motor rotation speed sensor 7.

[0013] The front wheel drive motor 4f outputs torque to drive the front wheels 2a and 2b. The front wheel 2a corresponds to the right front wheel, and the front wheel 2b corresponds to the left front wheel.

[0014] The front-wheel drive motor 4f is driven using power supplied from a battery 6. The front-wheel drive motor 4f is connected to a front differential 3f. The front differential 3f is connected to the front wheels 2a, 2b via drive shafts. The torque output from the front-wheel drive motor 4f is transmitted to the front differential 3f, and then distributed and transmitted to the front wheels 2a, 2b by the front differential 3f.

[0015] The front-wheel drive motor 4f is, for example, a polyphase AC motor, and is connected to the battery 6 via an inverter 5f. DC power supplied from the battery 6 is converted into AC power by the inverter 5f and supplied to the front-wheel drive motor 4f.

[0016] In addition to the function of outputting drive torque for the front wheels 2a, 2b, the front-wheel drive motor 4f may also function as a generator that generates electricity using the kinetic energy of the front wheels 2a, 2b. When the front-wheel drive motor 4f functions as a generator, the front-wheel drive motor 4f generates electricity and applies braking force to the vehicle 1 through regenerative braking. The AC power generated by the front-wheel drive motor 4f is converted to DC power by the inverter 5f and supplied to the battery 6. The battery 6 can be charged with the DC power supplied from the inverter 5f.

[0017] The rear wheel drive motor 4r outputs torque to drive the rear wheels 2c and 2d. The rear wheel 2c corresponds to the right rear wheel, and the rear wheel 2d corresponds to the left rear wheel.

[0018] The rear-wheel drive motor 4r is driven using power supplied from a battery 6. The rear-wheel drive motor 4r is connected to a rear differential 3r. The rear differential 3r is connected to the rear wheels 2c and 2d via drive shafts. Torque output from the rear-wheel drive motor 4r is transmitted to the rear differential 3r, and then distributed and transmitted to the rear wheels 2c and 2d by the rear differential 3r.

[0019] The rear wheel drive motor 4r is, for example, a polyphase AC motor, and is connected to the battery 6 via an inverter 5r. DC power supplied from the battery 6 is converted into AC power by the inverter 5r and supplied to the rear wheel drive motor 4r.

[0020] In addition to the function of outputting drive torque for the rear wheels 2c, 2d, the rear-wheel drive motor 4r may also function as a generator that generates electricity using the kinetic energy of the rear wheels 2c, 2d. When the rear-wheel drive motor 4r functions as a generator, the rear-wheel drive motor 4r generates electricity and applies braking force to the vehicle 1 through regenerative braking. The AC power generated by the rear-wheel drive motor 4r is converted to DC power by the inverter 5r and supplied to the battery 6. The battery 6 can be charged with the DC power supplied from the inverter 5r.

[0021] The front wheel motor rotation speed sensor 7f detects the rotation speed of the front wheel drive motor 4f and outputs the detection result. The rotation speed of the front wheel drive motor 4f detected by the front wheel motor rotation speed sensor 7f may correspond to information indicating the wheel speed of the front wheels 2a, 2b.

[0022] The rear wheel motor rotation speed sensor 7r detects the rotation speed of the rear wheel drive motor 4r and outputs the detection result. The rotation speed of the rear wheel drive motor 4r detected by the rear wheel motor rotation speed sensor 7r can correspond to information indicating the wheel speed of the rear wheels 2c, 2d.

[0023] The control device 10 communicates with each device mounted on the vehicle 1. For example, the control device 10 communicates with the inverter 5f, the inverter 5r, the front wheel motor rotation speed sensor 7f, and the rear wheel motor rotation speed sensor 7r. The communication between the control device 10 and each device is realized, for example, using CAN (Controller Area Network) communication.

[0024] The control device 10 can independently control the braking / driving forces of the front wheels 2a, 2b and the rear wheels 2c, 2d of the vehicle 1. In particular, in this embodiment, when the control device 10 detects an intention of the driver (user) of the vehicle 1 to drift, it controls the braking / driving forces of the front wheels 2a, 2b so as to maintain a constant slip ratio of the front wheels 2a, 2b. In the following description, this control may also be referred to as "front wheel slip suppression control."

[0025] Here, the reason why front wheel slip suppression control is performed in this embodiment will be explained. In a vehicle like the vehicle 1 illustrated in FIG. 1, in which the braking / driving forces of the front wheels 2a, 2b and the rear wheels 2c, 2d can be controlled independently, torque distribution control can be performed to freely change the torque (braking / driving force) distribution between the front wheels 2a, 2b and the rear wheels 2c, 2d depending on various conditions, such as the movement of the wheels 2 and road surface conditions. In this torque distribution control, if the maximum torque of the front wheels 2a, 2b is high (i.e., if the torque distribution ratio of the front wheels 2a, 2b is greater than that of the rear wheels 2c, 2d), drifting may result in understeer. When understeer occurs, the front wheels 2a, 2b slip, and the turning trajectory of the vehicle 1 diverges outward from the target trajectory. This makes it impossible to transition to drifting.

[0026] Therefore, in this embodiment, front wheel slip suppression control is implemented under conditions where understeer may occur. This suppresses slippage of the front wheels 2a, 2b, making it possible to control the vehicle 1 so as to suppress understeer as well, making it easier to perform drifting. As a result, the vehicle 1 can be made to drive in a manner that more closely matches the user's intentions.

[0027] The control device 10 can be physically configured as a computer system including a CPU (Central Processing Unit), RAM (Random Access Memory) and ROM (Read Only Memory) as main storage devices, an input device, an output device, a communication module, an auxiliary storage device, etc. Each function of the control device 10 is realized by loading predetermined computer software onto hardware such as the CPU and RAM, thereby operating the communication module, input device, and output device under the control of the CPU, and reading and writing data from and to the RAM and auxiliary storage device. The control device 10 may also be implemented as part of an ECU (Electronic Control Unit) of the vehicle 1 in which the control device is installed.

[0028] The functions of the control device 10 according to the present embodiment may be divided among multiple control devices, or multiple functions may be realized by one control device. When the functions of the control device 10 are divided among multiple control devices, the multiple control devices may be connected to each other via a communication bus such as a CAN.

[0029] Fig. 2 is a flowchart of the front wheel slip suppression control according to the embodiment. Each process in the flowchart shown in Fig. 2 is performed by the control device 10 in Fig. 1. The front wheel slip suppression control explained in the flowchart of Fig. 2 is performed, for example, at predetermined intervals.

[0030] In step S10, it is determined whether the vehicle 1 equipped with the control device 10 is in drift mode. If the vehicle 1 is provided with a function that allows the driver's seat to switch the drift mode on and off, the control device 10 can determine that the vehicle is in drift mode when the drift mode is in the ON state.

[0031] If the vehicle is in drift mode (Yes in step S10), the process proceeds to step S20. On the other hand, if the vehicle is not in drift mode (No in step S10), the user's (driver's) intention to drift is not detected, so it is determined that front wheel slip suppression control is not required, and the control flow ends.

[0032] The determination in step S10 does not need to be performed if the vehicle 1 is not provided with a function that allows the driver's seat to switch the drift mode on and off.

[0033] In step S20, it is determined whether or not the steering angle of the vehicle 1 equipped with the control device 10 is greater than a predetermined threshold value T1. The steering angle corresponds to the steering angle of the front wheels 2a, 2b, for example.

[0034] If the steering angle is greater than the threshold value T1 (Yes in step S20), the process proceeds to step S30. On the other hand, if the steering angle is equal to or less than the threshold value T1 (No in step S20), the user's (driver's) intention to drift is not detected, so it is determined that front wheel slip suppression control does not need to be performed, and the control flow ends.

[0035] In step S30, it is determined whether the longitudinal G of the vehicle 1 equipped with the control device 10 is greater than a predetermined threshold value T2. The longitudinal G is the acceleration occurring in the longitudinal direction of the vehicle 1. Since this control is intended to be performed during drifting, the threshold value T2 can be set to any positive value.

[0036] If the longitudinal G is greater than the predetermined threshold T2 (Yes in step S20), the process proceeds to step S30. On the other hand, if the longitudinal G is equal to or less than the predetermined threshold T2 (No in step S20), the user's (driver's) intention to drift is not detected, so it is determined that front wheel slip suppression control does not need to be performed, and this control flow ends.

[0037] In step S40, since it can be determined from the results of the determinations in steps S10, S20, and S30 that the user's (driver's) intention to drift has been detected, the braking / driving force of the front wheels 2a, 2b is controlled so that the slip ratio remains constant. In this step, the control device 10 can control the slip ratio of the front wheels 2a, 2b (=(wheel speed-vehicle speed) / vehicle speed) to remain constant, for example, by using the torque or brakes transmitted to the front wheels 2a, 2b.

[0038] By carrying out the flowchart of the front wheel slip suppression control shown in FIG. 2, slip of the front wheels 2a, 2b can be suppressed, so that the occurrence of understeer can be suppressed and drifting of the vehicle 1 can be facilitated.

[0039] 2, the slip ratio control in step S40 can be performed only when the user's drifting intention is detected based on the determination results of steps S10, S20, and S30. This enables the front wheel slip suppression control to be enabled only when the user performs a drifting operation while cornering. As a result, the vehicle 1 can be driven in a manner that more closely matches the user's intention.

[0040] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0041] 1 vehicle 2a, 2b front wheel 2c, 2d rear wheel 10 Control device

Claims

[Claim 1] A vehicle control device capable of independently controlling the braking and driving forces of front and rear wheels, When a user's intention to drift is detected, the braking / driving force of the front wheels is controlled so as to maintain a constant slip ratio of the front wheels. Vehicle control device.

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