JP6898843B2 - Electric vehicle controls, control methods and control systems - Google Patents

Description

The present invention relates to a control device, a control method and a control system for an electric vehicle.

Patent Document 1 describes that in an electric vehicle that executes so-called one-pedal control in which a braking force is applied to a vehicle to stop the vehicle when the accelerator pedal is stepped back from a predetermined position, the brake pedal is used while the vehicle is stopped or traveling at a low speed. A technique for outputting creep torque when stepped on is disclosed. If the accelerator pedal is depressed beyond a predetermined position during creep torque output, creep torque output is prohibited.

JP-A-2017-47746

In the above-mentioned conventional technique, when the accelerator pedal is stepped on during the parking operation, the creep torque output is prohibited, and when the accelerator pedal is stepped back after that, the vehicle is stopped by one-pedal control. Therefore, in the above-mentioned conventional technique, there is a possibility that the operability at the time of parking, which requires the accelerator operation, deteriorates.
One of an object of the present invention is to provide a control device, a control method, and a control system for an electric vehicle capable of suppressing deterioration of operability during parking that requires accelerator operation.

When a signal relating to the depression of the accelerator pedal is input from the accelerator pedal sensor, the control device for the electric vehicle according to the embodiment of the present invention outputs a command to generate a regenerative braking force to the electric motor, and the vehicle body speed detection sensor outputs a command to generate a regenerative braking force. When an output value lower than the predetermined speed is input and an output value higher than the predetermined steering angle is input from the steering angle detection sensor, a command to generate creep torque is output to the electric motor.

Therefore, according to the present invention, deterioration of operability at the time of parking, which requires accelerator operation, can be suppressed.

It is a figure which shows the control system of the electric vehicle of Embodiment 1. FIG. It is a flowchart which shows the flow of the creep output permission determination control of Embodiment 1. It is a time chart which shows the operation of the creep output permission determination control of Embodiment 1.

[Embodiment 1]
FIG. 1 is a diagram showing a control system for an electric vehicle according to the first embodiment.
An electric vehicle (hereinafter referred to as a vehicle) is a front-wheel drive vehicle and has wheels FL, FR, RL, and RR. The front wheels FL and FR are the driving wheels, and the rear wheels RL and RR are the driven wheels. A wheel cylinder 1 and a wheel speed sensor (vehicle body speed detection sensor) 2 are attached to each wheel. The wheel cylinder 1 presses a brake pad against a brake rotor that rotates integrally with the tire to generate a friction braking force. The wheel speed sensor 2 detects the wheel speed of the corresponding wheel. The hydraulic pressure unit 3 is connected to the wheel cylinder 1 via the hydraulic pressure pipe 1a. The hydraulic unit 3 has a plurality of solenoid valves, a reservoir, and a motor for a pump. The hydraulic pressure unit 3 applies a braking force to each wheel by controlling the driving state of each solenoid valve and the pump motor based on the hydraulic pressure command from the brake controller 6. The brake controller 6 outputs a hydraulic pressure command corresponding to a friction braking command from the vehicle controller (control unit) 18, which will be described later, to the hydraulic pressure unit 3.

The vehicle has a motor generator (an electric motor, hereinafter referred to as a motor) 7 as a power source for driving the front wheels FL and FR. The motor 7 has a resolver 7a that detects the rotation angle of the motor. The motor 7 is connected to the front wheels FL and FR via a reduction mechanism 8, a differential gear 9, and a drive shaft 10. The vehicle has a high voltage battery 11 and a battery controller 12. The high-voltage battery 11 supplies electric power to the motor 7 during the power running operation of the motor 7, and recovers the generated electric power of the motor 7 during the regenerative operation of the motor 7. An auxiliary battery 14 is connected to the high-voltage battery 11 via a DC-DC converter 13. The auxiliary battery 14 functions as a driving power source for the hydraulic unit 3. The battery controller 12 monitors the state of the high-voltage battery 11 and controls the state of the high-voltage battery 11 in response to a battery control command from the vehicle controller 18. An inverter 15 is installed between the high-voltage battery 11 and the motor 7. The inverter 15 controls the output torque of the motor 7 based on the inverter drive signal from the motor controller 16. The motor controller 16 outputs an inverter drive signal corresponding to the torque command from the vehicle controller 18 to the inverter 15.

The vehicle controller 18, the brake controller 6, the motor controller 16, and the battery controller 12 communicate with each other via the CAN communication line 17. The vehicle controller 18 has a steering operation amount signal from the steering angle sensor (steering angle detection sensor) 19, an accelerator opening signal from the accelerator opening sensor (accelerator pedal sensor) 20, and a brake stroke sensor (brake pedal sensor) 21. Input the brake operation amount signal. The steering angle sensor 19 detects the steering angle (hereinafter, steering operation amount) of the steering wheel 22. The accelerator opening sensor 20 detects the opening degree of the accelerator pedal 23 (hereinafter referred to as the accelerator opening degree). The brake stroke sensor 21 detects the operation amount of the brake pedal 24 (hereinafter, the brake operation amount). Further, the vehicle controller 18 inputs the vehicle body speed signal calculated by the brake controller 6 via the CAN communication line 17. The brake controller 6 calculates the vehicle body speed based on each wheel speed detected by the wheel speed sensor 2.

The vehicle controller 18 calculates a required driving force or a required braking force of the vehicle according to each input signal. The required driving force is set to a larger value as the accelerator opening is higher or the vehicle body speed is lower. The vehicle controller 18 sets a torque command for realizing the calculated required driving force. It should be noted that while the accelerator opening is 0 and the vehicle body speed is, for example, 10 km / h or less, the creep phenomenon of the AT vehicle is simulated and the motor 7 is required to output a minute torque as the creep torque. The driving force is calculated. The required braking force is set to a larger value as the braking operation amount is larger. The vehicle controller 18 sets a torque command and a friction braking command for realizing the calculated required braking force. The vehicle controller 18 sets a torque command and a friction braking command so that the sum of the regenerative braking force and the friction braking force becomes the required braking force as the regenerative cooperative control. At this time, the regenerative braking force is prioritized over the friction braking force, and the torque command and the friction braking command are set so as to realize the required braking force only by the regenerative braking force as much as possible to improve the energy recovery efficiency. When the vehicle is coasting with the brake operation amount being 0 and the accelerator opening being 0, the required braking force that simulates engine braking is calculated.

When the accelerator pedal 23 is stepped back and the accelerator opening becomes equal to or less than a predetermined opening, the vehicle controller 18 of the first embodiment applies braking force to the vehicle instead of the creep torque output to stop the vehicle. Perform one-pedal control. The required braking force during one-pedal control increases as the accelerator opening approaches 0, and takes the maximum value when the accelerator opening is 0. The higher the return speed of the accelerator pedal 23, the larger the required braking force may be. The maximum value of the required braking force is appropriately set as the braking force (stop braking force) required to stop the vehicle. The stopping braking force is corrected according to the road surface gradient, the friction coefficient between the tires and the road surface, the vehicle weight, and the like. Regenerative braking force is prioritized even in one-pedal control, but since regenerative braking force cannot be generated when the vehicle is stopped, the regenerative braking force is replaced with frictional braking force immediately before the vehicle is stopped, and the stopped state is maintained by the frictional braking force. To.
With the above one-pedal control, deceleration, stopping, and holding can be realized only by depressing the accelerator pedal 23. However, when the one-pedal mode that allows the intervention of one-pedal control is ON, creep torque is not generated, so that the driver is forced to perform complicated operations in a scene where the vehicle is stopped and the vehicle is running at low speed alternately, such as in a traffic jam. At this time, by turning off the one-pedal mode, it is possible to switch to the normal mode in which creep torque is generated, but since manual operation is required to switch the mode, the operating load increases.

On the other hand, even when the one-pedal mode is ON, when the brake pedal is depressed while the vehicle is stopped or running at low speed, creep torque is output instead of braking force until the accelerator pedal is depressed. The technology is known. In this conventional technique, the vehicle position can be adjusted only by operating the brake, so that the drivability in a traffic jam or the like can be improved. However, the above-mentioned conventional technique has a problem in operability at the time of parking, which requires an accelerator operation. More specifically, when there is a road surface with a large running resistance on the parking route such as a gravel parking lot or a slope, the driving force is insufficient only with the creep torque, so acceleration by accelerator operation is required. In the above-mentioned prior art, the creep torque output is prohibited by the accelerator operation, and the vehicle stops when the accelerator pedal is depressed. Therefore, in the above-mentioned conventional technique, the vehicle repeatedly starts and stops each time the driver operates the accelerator, which may deteriorate the operability.
Therefore, the vehicle controller 18 of the first embodiment aims to suppress deterioration of operability during parking that requires accelerator operation, and executes creep output permission determination control as shown below when the one-pedal mode is ON. To do.

FIG. 2 is a flowchart showing the flow of creep output permission determination control according to the first embodiment. This control is repeatedly executed in a predetermined calculation cycle when the one-pedal mode is ON.
In step S1, it is determined whether the vehicle body speed is equal to or less than the low speed determination speed. If YES, proceed to step S2, and if NO, proceed to step S8. The low-speed judgment speed is an upper limit of the vehicle body speed assumed during the parking operation, and is set to, for example, 10 Km / h.
In step S2, it is determined whether the driver is in the parking operation. If YES, proceed to step S9, and if NO, proceed to step S3. In this step, if the parking operation flag F1 is set (F1 = 1), it is determined that the parking operation is in progress, and if the reset F1 (= 0) is set, it is determined that the parking operation is not in progress. To do.
In step S3, it is determined whether there is a driver's stop request. If YES, proceed to step S4, and if NO, proceed to step S5. In this step, if the stop request flag F2 is set (F2 = 1), it is determined that there is a stop request, and if it is reset (F2 = 0), it is determined that there is no stop request.

In step S4, it is determined whether the steering operation amount is equal to or greater than the parking determination steering angle. If YES, proceed to step S10, and if NO, proceed to step S7. The parking judgment steering operation amount is the steering operation amount assuming that the vehicle is parked, and is set to, for example, 90 °.
In step S5, it is determined whether the brake operation amount is larger than the stop request determination operation amount. If YES, proceed to step S6, and if NO, proceed to step S13. The stop request determination operation amount is a brake operation amount that is assumed that the driver is operating the brake, and is, for example, a brake operation amount such that the brake lamp lights up.
In step S6, the stop request flag F2 is set (F2 = 1).
In step S7, it is determined whether the accelerator opening is positive (> 0). If YES, proceed to step S11, and if NO, proceed to step S12. In this step, it is determined whether the driver is operating the accelerator.
In step S8, as in step S7, it is determined whether the accelerator opening is positive (> 0). If YES, proceed to step S13, and if NO, proceed to return.

In step S9, the creep torque output is permitted and the process proceeds to return. When the creep torque output is permitted, the required braking force is calculated so that the creep torque is such that a vehicle body speed of 6 to 7 Km / h can be obtained on a flat road, for example. When the creep torque output is permitted, even if the accelerator pedal 23 is stepped back, the application of braking force in one-pedal control is prohibited.
In step S10, the parking operation flag F1 is set (F1 = 1), the creep torque output is permitted, and the process proceeds to return.
In step S11, the creep torque output is prohibited, the stop request flag F2 is reset (F2 = 0), and the process proceeds to return. When the creep torque output is prohibited, when the accelerator pedal 23 is stepped back, braking force is applied by one-pedal control.
In step S12, as in step S9, the creep torque output is permitted and the process proceeds to return.
In step S13, the parking operation flag F1 and the stop request flag F2 are reset (F1 = 0, F2 = 0), and the creep torque output is prohibited and the process proceeds to return as in step S11.

Next, the action and effect of the first embodiment will be described.
FIG. 3 is a time chart showing the operation of the creep output permission determination control of the first embodiment. As a comparative example, a broken line shows a line that prohibits the output of creep torque when the accelerator pedal is depressed.
Before the time t1, the vehicle body speed is higher than the low speed determination speed and the accelerator opening is 0. Therefore, in the flowchart of FIG. 2, the flow of S1 → S8 is repeated. Since the output of creep torque is not permitted, the torque command value is the regenerative braking torque in one-pedal control, and the vehicle is decelerated by the braking force (regenerative braking force).
At time t1, since the vehicle body speed coincided with the low speed determination speed, the flow chart of FIG. 2 shows the flow of S1 → S2 → S3 → S5 → S13, and the regenerative braking torque is continuously applied.
At time t2, the steering operation amount is larger than the parking judgment steering operation amount, and the brake operation amount is larger than the stop request judgment operation amount. Therefore, in the flowchart of FIG. 2, S1 → S2 → S3 → S5 → S6 → Proceed from S4 to S10, the parking operation flag F1 is set (ON), and creep torque output is permitted. As a result, the flow is S1 → S2 → S9, and the creep torque output is permitted. Since the torque command changes from the regenerative braking torque to the creep torque, the vehicle starts.

At time t3, the driver starts the accelerator operation. In the flowchart of FIG. 2, since the flow of S1 → S2 → S9 is maintained, the creep torque output is continued. Since the torque command increases with the accelerator opening, the driver can obtain the desired acceleration.
At time t4, the driver begins braking. In the flowchart of FIG. 2, since the flow of S1 → S2 → S9 is maintained, the creep torque output is continued. Since the torque command is creep torque, the driver can adjust the vehicle position only by operating the brake.
At time t5, the vehicle stops at the parking position.
In the comparative example, since the creep torque output is prohibited at time t3, when the driver depresses the accelerator pedal, the torque command becomes the regenerative braking torque and the vehicle stops. For this reason, when parking requires an accelerator operation, the vehicle repeatedly starts and stops each time the accelerator is operated, forcing the driver to perform complicated operations.
On the other hand, in the creep output permission determination control of the first embodiment, when the vehicle body speed is equal to or lower than the low speed determination speed and it is determined that the parking operation is in progress (the steering operation amount is the parking determination steering operation amount in the previous calculation cycle). In the above cases), the creep torque output is permitted regardless of the accelerator operation and brake operation (S1 → S2 → S9). As a result, the vehicle position can be adjusted only by operating the brake even after the accelerator is operated, so that deterioration of operability during parking, which requires the accelerator operation, can be suppressed. Further, since the driver does not need to turn off the one-pedal mode every time the parking operation is performed, an increase in the driving load can be suppressed.

In the creep output permission determination control of the first embodiment, when the vehicle body speed is equal to or less than the low speed determination speed, the brake operation amount is larger than the stop request determination operation amount, and the steer operation amount is equal to or more than the parking judgment steer operation amount, parking is performed. Judging that it is in operation, the creep torque output is permitted (S1 → S2 → S3 → S5 → S6 → S4 → S10), and the creep torque output is permitted during parking operation regardless of accelerator operation and brake operation (S1). → S2 → S9). By looking at the presence or absence of the driver's stop request in addition to the steering operation amount, it is possible to more accurately determine whether or not the parking operation is in progress.
In the creep output permission determination control of the first embodiment, when the vehicle body speed is equal to or lower than the low speed determination speed, the steering operation amount is less than the parking determination steering operation amount, and the accelerator opening is 0, the creep torque output is permitted. (S1 → S2 → S3 → S4 → S7 → S12). That is, even when the parking operation is not performed, the creep torque output is permitted when the accelerator operation is not performed. As a result, the driver can adjust the inter-vehicle distance only by operating the brake in a traffic jam, so that deterioration of operability can be suppressed.
In the creep output permission determination control of the first embodiment, when the vehicle body speed is equal to or less than the low speed determination speed, the steering operation amount is less than the parking determination steering operation amount, and the accelerator opening is larger than 0, the creep torque output. Is prohibited (S1 → S2 → S3 → S4 → S7 → S11). That is, when the driver is not in the parking operation and it is determined that the driver has the intention of accelerating the vehicle, the creep torque output is prohibited and the one-pedal control is activated. As a result, when the distance from the preceding vehicle is reduced by the accelerator operation after the distance from the preceding vehicle is reduced during a traffic jam, deceleration, stopping, and holding of the vehicle can be realized only by depressing the accelerator pedal 23.

[Other Embodiments]
Although the embodiments for carrying out the present invention have been described above, the specific configuration of the present invention is not limited to the configurations of the embodiments, and there are design changes and the like within a range that does not deviate from the gist of the invention. Is also included in the present invention.
In the first embodiment, the accelerator opening sensor 20 that detects the accelerator opening is used as the accelerator pedal sensor, but the accelerator pedal sensor is an arbitrary sensor as long as it can detect the physical quantity (depressed amount and depressed amount) related to the stroke of the accelerator pedal. May be used.
In the first embodiment, the wheel speed sensor 2 (value obtained from the detected value) that detects each wheel speed is used as the vehicle body speed detection sensor, but the vehicle body speed detection sensor is arbitrary as long as it can detect a physical quantity related to the vehicle body speed. A sensor may be used.
In the first embodiment, the steering angle sensor 19 that detects the steering angle of the steering wheel 22 is used as the steering angle detection sensor, but any sensor may be used as the steering angle detection sensor as long as it can detect the physical quantity related to the steering angle.
In the first embodiment, the brake stroke sensor 21 that detects the operation amount of the brake pedal 24 is used as the brake pedal sensor, but the brake pedal sensor is arbitrary as long as it can detect the physical quantity (depression amount and step back amount) related to the stroke of the brake pedal. Sensor may be used.
The electric vehicle may be a rear-wheel drive vehicle or a four-wheel drive vehicle.

2 Wheel speed sensor (body speed detection sensor)
7 motor (electric motor)
18 Vehicle controller (control unit)
19 Steering angle sensor (rudder angle detection sensor)
20 Accelerator opening sensor (accelerator pedal sensor)
21 Brake stroke sensor (brake pedal sensor)
23 Accelerator pedal
24 Brake pedal
FL, FR Front wheels (wheels)
RL, RR Rear wheels (wheels)

Claims (4)

A control device for an electric vehicle equipped with an electric motor that applies regenerative braking force to the wheels of the vehicle.
When a signal related to the depression of the accelerator pedal is input from the accelerator pedal sensor that detects the physical quantity related to the stroke of the accelerator pedal of the vehicle, a command to generate the regenerative braking force is output to the electric motor.
An output value lower than a predetermined speed is input from the vehicle body speed detection sensor that detects the physical quantity related to the vehicle body speed of the vehicle, and a signal relating to the depression of the brake pedal is input from the brake pedal sensor that detects the physical quantity related to the stroke of the brake pedal of the vehicle. is input, and the output value exceeding the predetermined steering angle from the steering angle sensor for detecting a physical quantity relating to a steering angle of the vehicle is input, the control device for an electric vehicle for outputting a command to generate a creep torque to the electric motor .. In the control device for an electric vehicle according to claim 1,
An output value lower than a predetermined speed is input from the vehicle body speed detection sensor, an output value lower than a predetermined steering angle is input from the steering angle detection sensor, and a signal relating to depression of the accelerator pedal is input from the accelerator pedal sensor. Then, a control device for an electric vehicle that outputs a command to prohibit creep torque to the electric motor. When a signal related to the depression of the accelerator pedal is input from the accelerator pedal sensor that detects the physical amount related to the stroke of the accelerator pedal of the vehicle, the electric motor that applies the regenerative braking force to the wheels of the vehicle generates the regenerative braking force. Output the command,
An output value lower than a predetermined speed is input from the vehicle body speed detection sensor that detects the physical quantity related to the vehicle body speed of the vehicle, and a signal relating to the depression of the brake pedal is input from the brake pedal sensor that detects the physical quantity related to the stroke of the brake pedal of the vehicle. is input, and the output value exceeding the predetermined steering angle from the steering angle sensor for detecting a physical quantity relating to a steering angle of the vehicle is input, the control method of an electric vehicle for outputting a command to generate a creep torque to the electric motor .. An electric motor that applies regenerative braking force to the wheels of the vehicle,
An accelerator pedal sensor that detects a physical quantity related to the stroke of the accelerator pedal of the vehicle, and
A vehicle body speed detection sensor that detects a physical quantity related to the vehicle body speed of the vehicle,
When a signal relating to the depression / return of the accelerator pedal is input from the accelerator pedal sensor, a command for generating the regenerative braking force is output to the electric motor, and an output value lower than a predetermined speed is input from the vehicle body speed detection sensor. In addition, a signal related to the depression of the brake pedal is input from the brake pedal sensor that detects the physical quantity related to the stroke of the brake pedal of the vehicle, and the steering angle exceeds a predetermined steering angle from the steering angle detection sensor that detects the physical quantity related to the steering angle of the vehicle. When an output value is input, a control unit that outputs a command to generate creep torque to the electric motor, and
An electric vehicle control system equipped with.

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