Control method of electric vehicle, motor controller and electric vehicle

Abstract

The invention provides a control method of an electric vehicle, a motor controller and the electric vehicle, and is applied to the technical field of electric vehicles. The control method is used for controlling the driving system to improve the stability of the speed of the electric vehicle after the off-road cruise function of the electric vehicle is started. Comprising the steps that at the first moment, the opening degree of an accelerator pedal of the electric vehicle is smaller than the preset accelerator pedal opening degree, the opening degree of a brake pedal is smaller than the preset brake pedal opening degree, and a driving motor of the electric vehicle is controlled to output torque so that the electric vehicle can run at the preset speed; at a second moment after the first moment, the road surface load of the road surface in contact with any wheel of the electric vehicle changes relative to the road surface load of the road surface in contact with the wheels at the first moment, and the driving motor is actively controlled to adjust torque output. Therefore, the torque output of the driving motor is controlled to stabilize the vehicle speed near the preset vehicle speed in response to the road load change in time, the stability of the vehicle speed in off-road cruise is improved, and the driving experience is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a control method for an electric vehicle, a motor controller and an electric vehicle. Background Art

[0002] Most electric vehicles are now equipped with an off-road cruise function, which is used to automatically control the electric vehicle to travel at the speed set by the driver when the electric vehicle is driving on complex off-road terrain (such as bumpy roads with potholes and stones, sand or mud, etc.), so that the electric vehicle can easily go off-road or get out of trouble. However, when using the off-road cruise function, due to the complex road conditions and driving conditions of the vehicle in the off-road terrain, it is difficult for the control system of the electric vehicle to respond in time to control the electric vehicle to adjust the speed to stabilize at the speed set by the driver, resulting in large fluctuations in the speed, affecting the driving experience. Summary of the invention

[0003] The embodiments of the present application provide a control method for an electric vehicle, a motor controller, and an electric vehicle. After the off-road cruise function of the electric vehicle is activated, the electric vehicle is actively controlled to adjust the torque output by promptly responding to changes in road load. The electric vehicle is promptly controlled to adjust the speed to stabilize near a preset speed, thereby improving the stability of the electric vehicle speed and further improving the driving experience.

[0004] In a first aspect, an embodiment of the present application provides a control method for an electric vehicle, the control method being used to control a drive system of the electric vehicle to improve the stability of the electric vehicle speed after an off-road cruise function of the electric vehicle is activated, the control method comprising:

[0005] At a first moment, the opening of the accelerator pedal of the electric vehicle is less than a preset accelerator pedal opening and the opening of the brake pedal is less than a preset brake pedal opening, and the drive motor of the electric vehicle is controlled to output torque so that the electric vehicle travels at a preset vehicle speed;

[0006] At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the drive motor is actively controlled to adjust the torque output.

[0007] Among them, the preset brake pedal opening and the preset accelerator pedal opening are both relatively small values, such as 5%, 8%, 10%, etc. If the opening of the accelerator pedal of the electric vehicle is smaller than the preset accelerator pedal opening and the opening of the brake pedal is smaller than the preset brake pedal opening, it can be considered that the user has not operated the brake pedal and the accelerator pedal or has not operated the brake pedal or the accelerator pedal significantly. At this time, the speed of the electric vehicle is controlled by the intelligent driving controller, not by the user operating the brake pedal and the accelerator pedal.

[0008] The preset speed may be the default speed of the off-road cruise function or the speed set by the user. The user may set the speed through the central control screen or through a mobile terminal associated with the electric vehicle. The specific setting method is not limited in the embodiment of the present application. The preset speed may be a smaller value, such as 10kph, 12kph, 15kph, etc.

[0009] In this embodiment, when the off-road cruise function is enabled in the electric vehicle, the drive motor of the electric vehicle is automatically controlled to output torque to enable the electric vehicle to travel when the opening of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening and the opening of the brake pedal is less than the preset brake pedal opening. This allows the electric vehicle to automatically control the driving speed in complex off-road terrain without the driver having to operate the accelerator pedal or brake pedal of the electric vehicle, thereby reducing the user's operating burden and helping drivers with insufficient driving experience to pass through off-road terrain.

[0010] Furthermore, when the off-road cruise function is enabled in an electric vehicle, the torque output of the drive motor is actively controlled to be adjusted according to the changes in the road load on the road surface contacted by the wheels of the electric vehicle, rather than responding to the torque signal issued by the electronic stability program through the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to changes in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0011] In an embodiment of the first aspect, the control method further includes: at the second moment, the road load increases, and actively controlling the drive motor to increase the torque output.

[0012] In this embodiment, the road load acts as resistance during vehicle driving. When the road load increases, the torque output of the drive motor needs to increase to maintain the stability of the electric vehicle speed. By actively controlling the drive motor to increase the torque output when the road load increases, the torque output of the drive motor is controlled in a timely manner to stabilize the vehicle speed near the preset speed, thereby improving the speed fluctuation problem caused by complex off-road terrain conditions, improving the stability of the electric vehicle speed, and improving the driving experience.

[0013] In an embodiment of the first aspect, the control method further includes: at the second moment, the road load decreases, and the drive motor is actively controlled to reduce the torque output.

[0014] In this embodiment, the road load acts as resistance during vehicle driving. When the road load is reduced, the torque output by the drive motor needs to be reduced to maintain the stability of the electric vehicle speed. By actively controlling the drive motor to reduce the torque output when the road load is reduced, the torque output of the drive motor is controlled in a timely manner to stabilize the vehicle speed near the preset speed, thereby improving the speed fluctuation problem caused by the complex off-road terrain conditions, improving the stability of the electric vehicle speed, and improving the driving experience.

[0015] In an embodiment of the first aspect, the control method also includes: at a third moment after the first moment, the preset vehicle speed is reduced, the drive motor is controlled to output a reverse torque and / or the braking system of the electric vehicle is actively controlled to output a braking force; the torque direction of the reverse torque is opposite to the rotation direction of the wheels of the electric vehicle; at a fourth moment after the third moment, the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the third moment, and the drive motor is actively controlled to adjust the reverse torque output and / or the braking system of the electric vehicle is actively controlled to adjust the braking force output.

[0016] In this embodiment, the preset speed reduction requires braking of the electric vehicle to reduce the adjusted speed to the preset speed after the reduction, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, thereby improving the driving experience. In the process of adjusting the electric vehicle to travel at the preset speed after the reduction, by actively controlling the drive motor to adjust the reverse torque output and / or actively controlling the brake system of the electric vehicle to adjust the braking force output according to the change of the road load of the road surface contacted by the wheels of the electric vehicle, rather than responding to the torque signal or brake signal issued by the electronic stability program through the vehicle controller to control the output, it is realized that the torque output of the drive motor and / or the braking force output of the brake system are controlled in time to the change of the road load so that the speed is reduced to the preset speed after the reduction at a stable deceleration, thereby improving the driving experience. At the same time, the braking method of the electric vehicle includes controlling the drive motor to output the reverse torque and controlling the brake system of the electric vehicle to output the braking force, thereby improving the braking flexibility, and when the reverse torque output by controlling the drive motor is insufficient to brake the electric vehicle, the braking can be achieved by controlling the brake system of the electric vehicle to output the braking force to improve the stability of the deceleration of the electric vehicle.

[0017] In an embodiment of the first aspect, the control method further includes: at a fourth moment, the road load increases, actively controlling the drive motor to increase the reverse torque output and / or actively controlling the braking system of the electric vehicle to increase the braking force output.

[0018] In this embodiment, the resistance when braking the electric vehicle increases as the road load increases. By actively controlling the drive motor to increase the reverse torque output and / or actively controlling the brake system of the electric vehicle to increase the braking force output when the road load increases, timely response to the increase in road load is achieved to control the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0019] In an embodiment of the first aspect, the control method further includes: at a fourth moment, the road load decreases, actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the braking system of the electric vehicle to reduce the braking force output.

[0020] In this embodiment, the resistance when braking the electric vehicle is reduced when the road load is reduced. By actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the brake system of the electric vehicle to reduce the braking force output when the road load is reduced, timely response to the reduction of the road load is achieved to control the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0021] In an embodiment of the first aspect, the control method also includes: after the first moment, if any wheel of the electric vehicle slips, actively controlling the drive motor to reduce the torque output; the slip of any wheel of the electric vehicle means that the slip rate or slip rate of any wheel is greater than a preset value.

[0022] In this embodiment, when any wheel of the electric vehicle slips, the torque output is reduced by actively controlling the drive motor rather than controlling the drive motor to adjust the torque output in response to the indication of the torque signal. In this way, the torque output of the drive motor is controlled in a timely manner in response to wheel slip to improve driving safety.

[0023] In an embodiment of the first aspect, the control method further includes: at a first moment, receiving a torque signal and controlling the drive motor to output the torque indicated by the torque signal; at a second moment, actively controlling the torque output by the drive motor to be greater than or less than the torque indicated by the torque signal.

[0024] In this embodiment, when the road load of the road surface contacted by any wheel of the electric vehicle changes, the torque output of the drive motor is actively controlled to be greater than or less than the torque indicated by the torque signal. That is to say, when the road load changes, the drive motor can be actively controlled to adjust the torque output, rather than responding to the torque signal indicated by the electronic stability program through the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to the change in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0025] In an embodiment of the first aspect, the control method also includes: at a first moment, receiving a speed signal and controlling the drive motor to output torque so that the electric vehicle travels at a preset speed indicated by the speed signal; at a second moment, receiving a speed signal and actively controlling the drive motor to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal.

[0026] In this embodiment, the purpose of controlling the output torque of the drive motor at the first moment and the second moment is to automatically control the electric vehicle to travel at the speed indicated by the speed signal. The road load of the road surface contacted by any wheel of the electric vehicle changes, and the torque output is adjusted by actively controlling the drive motor to make the electric vehicle travel at the preset speed indicated by the speed signal, so as to achieve timely response to the change of road load and control the torque output of the drive motor to stabilize the vehicle speed at the preset speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience.

[0027] In an embodiment of the first aspect, the control method further includes: at the second moment, actively controlling the increased torque output by the drive motor to be less than or equal to a preset torque; the smaller the adhesion coefficient of the road surface, the smaller the preset torque.

[0028] Among them, the adhesion coefficient determines the road adhesion capacity, and the preset torque is the torque corresponding to the road adhesion capacity.

[0029] In this embodiment, by setting a preset torque and actively controlling the increased torque output by the drive motor to be less than or equal to the preset torque, wheel slippage during off-road cruising is avoided, thereby improving driving safety. In addition, the preset torque decreases as the adhesion coefficient decreases, so that the electric vehicle can still avoid wheel slippage in the case of complex off-road terrain conditions, thereby improving the driving experience.

[0030] In an embodiment of the first aspect, the control method also includes: at the second moment, the increase in the road load is a first increase, and the torque output by the actively controlled drive motor is a first torque; at the second moment, the increase in the road load is a second increase, and the torque output by the actively controlled drive motor is a second torque; the first increase is greater than the second increase, and the first torque is greater than the second torque.

[0031] In this embodiment, the road load acts as resistance during vehicle driving. When the increase in the road load is large, the torque output by the drive motor is actively controlled to be larger, and when the increase in the road load is small, the torque output by the drive motor is actively controlled to be smaller. This allows the torque output by the drive motor to overcome the road load while stabilizing the vehicle speed near a preset speed during off-road cruising of the electric vehicle, thereby improving the speed stability of the electric vehicle during off-road cruising and enhancing the driving experience.

[0032] In an embodiment of the first aspect, the control method further includes: at the second moment, the greater the increase in the road load, the greater the increase in the torque output by the actively controlled drive motor.

[0033] In this embodiment, the road load acts as resistance during vehicle driving. The greater the increase in the road load, the greater the resistance during the driving of the electric vehicle. The increase in the torque output by the drive motor is increased by actively controlling the increase in the road load, so that during the off-road cruising of the electric vehicle, the increase in the torque output by the drive motor can be flexibly controlled according to the increase in the road load, so that the torque output by the drive motor can overcome the road load and stabilize the vehicle speed near the preset speed during the off-road cruising, thereby improving the stability of the electric vehicle speed during the off-road cruising and improving the driving experience.

[0034] In an embodiment of the first aspect, the control method also includes: at a fourth moment, the increase in the road load is a first increase, the reverse torque output by the actively controlled drive motor is the first reverse torque, and / or the braking force output by the braking system of the electric vehicle is actively controlled to be the first braking force; at a second moment, the increase in the road load is a second increase, the reverse torque output by the actively controlled drive motor is the second reverse torque, and / or the braking force output by the braking system of the electric vehicle is actively controlled to be the second braking force; the first increase is greater than the second increase, the first torque is greater than the second torque, and the first braking force is greater than the second braking force.

[0035] In this embodiment, the road load acts as resistance during vehicle driving. When the increase in the road load is large, the reverse torque output by the drive motor and / or the braking force output by the brake system are actively controlled to be larger, and when the increase in the road load is small, the reverse torque output by the drive motor and / or the braking force output by the brake system are actively controlled to be smaller. This achieves timely response to different increases in the road load by controlling the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed at a stable deceleration rate, thereby improving the driving experience.

[0036] In an embodiment of the first aspect, the control method further includes: at the fourth moment, the greater the increase in the road load, the greater the increase in the reverse torque output by the active control drive motor and / or the increase in the braking force output by the braking system.

[0037] In this embodiment, the road load acts as resistance during vehicle driving. The greater the increase in the road load, the greater the resistance during the driving of the electric vehicle. The increase in the torque output by the drive motor is increased by actively controlling the increase in the road load, so that during the off-road cruising of the electric vehicle, the increase in the torque output by the drive motor can be flexibly controlled according to the increase in the road load, thereby achieving timely response to different increases in the road load and controlling the torque output of the drive motor and / or the braking force output of the braking system to reduce the vehicle speed to the preset speed at a stable deceleration, thereby improving the driving experience.

[0038] In an embodiment of the first aspect, the control method further includes: at the second moment and the fourth moment, actively controlling the drive motor to adjust the torque output according to the motor torque signal and / or the resolver signal from the resolver sensor.

[0039] In this embodiment, the resolver signal and the motor torque signal are signals that can be directly obtained. The motor speed indicated by the resolver signal changes with the change of the road load. By actively controlling the drive motor to adjust the torque output according to the resolver signal and / or the motor torque signal from the resolver sensor, it is achieved to respond to the change of the road load in a timely manner to control the torque output of the drive motor to stabilize the vehicle speed near the preset vehicle speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience. At the same time, the resolver signal and the motor torque signal are higher in accuracy and better in stability than the wheel speed signal. According to the resolver signal and / or the motor torque signal, the change of the road load can be accurately identified, thereby improving the accuracy of the drive motor to adjust the torque output control.

[0040] In an embodiment of the first aspect, the control method also includes: at a second moment, the motor speed indicated by the resolver signal from the resolver sensor decreases, and the drive motor is actively controlled to increase the torque output; at a second moment, the motor speed indicated by the resolver signal from the resolver sensor increases, and the drive motor is actively controlled to reduce the torque output.

[0041] In this embodiment, a decrease in the motor speed indicated by the resolver signal indicates an increase in the road load. By actively controlling the drive motor to increase the torque output, a timely response to the increase in the road load is achieved by controlling the torque output of the drive motor to stabilize the vehicle speed near the preset speed. An increase in the motor speed indicated by the resolver signal indicates a decrease in the road load. By actively controlling the drive motor to reduce the torque output, a timely response to the change in the road load is achieved by controlling the torque output of the drive motor to stabilize the vehicle speed near the preset speed. This improves the problem of vehicle speed fluctuations caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0042] In an embodiment of the first aspect, the control method also includes: at the second moment, the greater the rate of decrease of the motor speed indicated by the resolver signal from the resolver sensor, the greater the increase in the torque output by the actively controlled drive motor; at the second moment, the greater the rate of increase of the motor speed indicated by the resolver signal from the resolver sensor, the greater the decrease in the torque output by the actively controlled drive motor.

[0043] In this embodiment, the greater the rate of decrease of the motor speed indicated by the rotary signal, the greater the increase in the road load, and the more obvious the fluctuation of the electric vehicle speed. The greater the increase in the torque output by the active control drive motor, the greater the increase in the torque output by the drive motor increases with the increase in the road load, so that the embodiment of the present application can improve the speed fluctuation problem under different road load increases and stabilize the vehicle speed near the preset speed. The greater the rate of increase of the motor speed indicated by the rotary signal, the greater the decrease in the road load, and the more obvious the fluctuation of the electric vehicle speed. The greater the decrease in the torque output by the active control drive motor, the greater the decrease in the torque output by the drive motor increases with the increase in the road load decrease, so that the embodiment of the present application can improve the speed fluctuation problem under different road load decreases and stabilize the vehicle speed near the preset speed, thereby improving the driving experience.

[0044] In an embodiment of the first aspect, the control method also includes: at a fourth moment, the motor speed indicated by the resolver signal from the resolver sensor decreases, and the drive motor is actively controlled to increase the reverse torque output and / or the braking system of the electric vehicle is actively controlled to increase the braking force output; at a second moment, the motor speed indicated by the resolver signal from the resolver sensor increases, and the drive motor is actively controlled to reduce the reverse torque output and / or the braking system of the electric vehicle is actively controlled to reduce the braking force output.

[0045] In this embodiment, a decrease in the motor speed indicated by the resolver signal indicates an increase in the road load. By actively controlling the drive motor to increase the reverse torque output and / or actively controlling the braking system of the electric vehicle to increase the braking force output, it is possible to respond promptly to the increase in the road load by controlling the torque output of the drive motor and / or the braking force output of the braking system so that the vehicle speed is reduced to a preset speed after the reduction at a stable deceleration rate. An increase in the motor speed indicated by the resolver signal indicates a decrease in the road load. By actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the braking system of the electric vehicle to reduce the braking force output, it is possible to respond promptly to the decrease in the road load by controlling the torque output of the drive motor and / or the braking force output of the braking system so that the vehicle speed is reduced to a preset speed after the reduction at a stable deceleration rate, thereby improving the driving experience.

[0046] In an embodiment of the first aspect, the control method also includes: at the fourth moment, the greater the decrease rate of the motor speed indicated by the resolver signal from the resolver sensor, the greater the increase in the reverse torque output by the actively controlled drive motor and / or the increase in the braking force output by the actively controlled brake system; at the second moment, the greater the increase rate of the motor speed indicated by the resolver signal from the resolver sensor, the greater the decrease in the reverse torque output by the actively controlled drive motor and / or the decrease in the braking force output by the actively controlled brake system.

[0047] In this embodiment, the greater the rate of decrease of the motor speed indicated by the rotary signal, the greater the increase in the road load, the more obvious the fluctuation of the electric vehicle speed, the greater the increase in the reverse torque output by the active control drive motor and / or the increase in the braking force output by the active control brake system, the greater the increase in the reverse torque and / or the increase in the braking force increases with the increase in the road load, so that under different conditions of the increase in the road load, the embodiment of the present application can reduce the vehicle speed to the preset speed after the reduction at a stable deceleration. The greater the rate of increase of the motor speed indicated by the rotary signal, the greater the decrease in the road load, the more obvious the fluctuation of the electric vehicle speed, the greater the decrease in the reverse torque output by the active control drive motor and / or the decrease in the braking force output by the active control brake system, the greater the decrease in the reverse torque and / or the decrease in the braking force increases with the increase in the decrease in the road load, so that under different conditions of the decrease in the road load, the embodiment of the present application can reduce the vehicle speed to the preset speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0048] In an embodiment of the first aspect, the control method also includes: at a third moment, the reduction in the preset vehicle speed is a first reduction, the reverse torque output by the drive motor is controlled to be the first reverse torque, and / or the braking force output by the braking system of the electric vehicle is controlled to be the first braking force; at a second moment, the reduction in the preset vehicle speed is a second reduction, the reverse torque output by the drive motor is controlled to be the second reverse torque, and / or the braking force output by the braking system of the electric vehicle is controlled to be the second braking force; the first reduction is greater than the second reduction, the first reverse torque is greater than the second reverse torque, and the first braking force is greater than the second braking force.

[0049] In this embodiment, a greater reduction in the preset vehicle speed causes a greater amount of braking to be required to adjust the electric vehicle to travel at the reduced preset vehicle speed. By controlling the reverse torque output by the drive motor and / or the braking force output by the braking system to be greater when the preset vehicle speed is reduced by a greater amount, and controlling the reverse torque output by the drive motor and / or the braking force output by the braking system to be smaller when the preset vehicle speed is reduced by a smaller amount, it is achieved that during off-road cruising of the electric vehicle, the electric vehicle can always travel at the speed desired by the user even when the speed desired by the user is reduced, thereby improving the driving experience.

[0050] In an embodiment of the first aspect, the control method also includes: at the third moment, the greater the reduction in the preset vehicle speed, the greater the increase in the reverse torque output by the drive motor and / or the increase in the braking force output by the braking system of the electric vehicle.

[0051] In this embodiment, the greater the reduction in the preset vehicle speed, the greater the braking required to adjust the electric vehicle to travel at the reduced preset vehicle speed. By controlling the increase in the reverse torque output by the drive motor and / or the increase in the braking force output by the braking system of the electric vehicle, the increase in the reverse torque and / or braking force output by the drive motor can be flexibly controlled according to the reduction in the preset vehicle speed during off-road cruising of the electric vehicle, thereby achieving the goal that during off-road cruising of the electric vehicle, the electric vehicle can always travel at the speed expected by the user even if the speed expected by the user is reduced, thereby improving the driving experience.

[0052] In an embodiment of the first aspect, the control method also includes: during the driving process of the electric vehicle after the off-road cruise function of the electric vehicle is activated, when the distance between the electric vehicle and an obstacle or the distance between the electric vehicle and other vehicles is less than a preset distance, controlling the drive motor to stop rotating.

[0053] The obstacle may be any object with a collision risk, such as an animal or a tree. The preset distance may be the distance from when the drive motors controlling the four wheels stop rotating to when the drive motors stop rotating, and when the drive motors stop rotating, there will be no collision with obstacles or other vehicles.

[0054] In this embodiment, a preset distance is set to avoid the situation where the distance between the electric vehicle and an obstacle or other vehicle is too small during the driving of the electric vehicle after the off-road cruise function of the electric vehicle is activated. The electric vehicle is continued to be controlled to prevent collision with the obstacle or other vehicle, thereby improving driving safety.

[0055] In a second aspect, an embodiment of the present application provides a motor controller, which is used to control the output torque of a drive motor to enable the electric vehicle to travel at a preset speed after the off-road cruise function of the electric vehicle is activated. The motor controller is specifically used to:

[0056] At a first moment, the opening of the accelerator pedal of the electric vehicle is less than a preset accelerator pedal opening and the opening of the brake pedal is less than a preset brake pedal opening, and the drive motor is controlled to output torque so that the electric vehicle travels at a preset vehicle speed;

[0057] At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the drive motor is actively controlled to adjust the torque output.

[0058] In this embodiment, at the second moment, the motor controller directly controls the drive motor to adjust the torque output, rather than controlling the drive motor to adjust the torque output in response to the torque signal issued by the electronic stability program through the vehicle controller, so that the operation of the motor controller and the drive motor is decoupled from the vehicle controller, so that after the road load changes, the motor controller can actively control the drive motor of the electric vehicle to adjust the torque output and promptly respond to the road load change to stabilize the vehicle speed at the preset speed, thereby improving the stability of the electric vehicle speed during off-road cruising, and thereby improving the driving experience.

[0059] In an embodiment of the second aspect, the motor controller is also used to receive a torque signal, and the motor controller is specifically used to: control the drive motor to output the torque indicated by the torque signal at a first moment; and control the drive motor to output a torque less than or greater than the torque indicated by the torque signal at a second moment.

[0060] In this embodiment, when the road load of the road surface contacted by any wheel of the electric vehicle changes, the motor controller actively controls the torque output of the drive motor to be greater than or less than the torque indicated by the torque signal. That is to say, when the road load changes, the motor controller can actively control the drive motor to adjust the torque output, rather than responding to the electronic stability program through the torque signal issued by the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to the change in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0061] In an embodiment of the second aspect, the motor controller is also used to receive a speed signal, and the motor controller is specifically used to: at a first moment, control the drive motor to output torque so that the electric vehicle travels at a preset speed indicated by the speed signal; at a second moment, actively control the drive motor to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal.

[0062] In this embodiment, the purpose of controlling the output torque of the drive motor at the first moment and the second moment is to automatically control the electric vehicle to travel at the speed indicated by the speed signal. When the road load of the road surface contacted by any wheel of the electric vehicle changes, the motor controller analyzes the speed signal and actively controls the drive motor to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal, rather than responding to the electronic stability program parsing the speed signal into a torque signal and controlling the drive motor to adjust the torque output through the instruction of the torque signal issued by the vehicle controller, so as to achieve timely response to the change of road load and control the torque output of the drive motor to stabilize the vehicle speed at the preset speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience.

[0063] In other embodiments of the second aspect, the motor controller is also used to execute the control method of the electric vehicle as described in other implementations of the first aspect.

[0064] In a third aspect, an embodiment of the present application provides an electric vehicle, the electric vehicle comprising four drive motors and the motor controller in the second aspect; wherein:

[0065] At the first moment, the motor controller is used to control the output torque of the four drive motors;

[0066] At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the motor controller is used to actively control the drive motor to adjust the torque output.

[0067] As for the supplementary and technical effects of the solutions provided in the second and third aspects above, please refer to the corresponding description of the first aspect and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A schematic diagram showing a control method for an electric vehicle is shown;

[0069] Figure 2 A schematic diagram of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0070] Figure 3 A schematic diagram showing the architecture of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0071] Figure 4 A schematic diagram showing a driving scene of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0072] Figure 5A schematic diagram showing a control method for an electric vehicle 100 provided in an embodiment of the present application is shown;

[0073] Figure 6 A schematic diagram showing a driving scene of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0074] Figure 7 A schematic diagram showing a control method for an electric vehicle 100 provided in an embodiment of the present application is shown;

[0075] Figure 8 A schematic diagram showing a control method for an electric vehicle 100 provided in an embodiment of the present application is shown;

[0076] Fig. 9 A schematic diagram showing a control method for an electric vehicle 100 provided in an embodiment of the present application is shown;

[0077] Fig.10 A schematic diagram showing a control method for an electric vehicle is shown;

[0078] Fig.11 A schematic diagram showing a control method for an electric vehicle 100 provided in an embodiment of the present application is shown;

[0079] Fig.12 A schematic diagram of a motor controller of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0080] Fig.13 A schematic diagram of a motor controller of an electric vehicle 100 provided in an embodiment of the present application is shown;

[0081] Fig.14 The following is a flowchart showing an operation of a motor controller of an electric vehicle 100 provided in an embodiment of the present application;

[0082] Fig.15 A schematic diagram of a motor controller of an electric vehicle 100 provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0083] The technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0084] The prefixes such as "first" and "second" used in the embodiments of the present application are only used to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers used to distinguish description objects in the embodiments of the present application does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and the use of such prefixes should not constitute an unnecessary limitation.

[0085] Most electric vehicles are now equipped with an off-road cruise function, which is used to automatically control the electric vehicle to travel at the speed set by the driver when the electric vehicle is driving on complex off-road terrain (such as bumpy roads with potholes and stones, sand or mud, etc.), so that the electric vehicle can easily go off-road or get out of trouble. However, when using the off-road cruise function, due to the complex road conditions and driving conditions of the vehicle in the off-road terrain, it is difficult for the control system of the electric vehicle to respond in time to control the electric vehicle to adjust the speed to stabilize at the speed set by the driver, resulting in large fluctuations in the speed, affecting the driving experience.

[0086] As an example, Figure 1 A schematic diagram of a control method for an electric vehicle is shown. Figure 1 In the present invention, after starting the off-road cruise function, the intelligent driving controller receives the speed signal fed back by the electric vehicle. If the speed indicated by the speed signal is inconsistent with the target speed set by the user, an acceleration signal is sent to the Electronic Stability Program (ESP), and ESP sends a braking command to the braking system in response to the acceleration signal to brake the electric vehicle, or ESP sends a torque command to the vehicle controller in response to the acceleration signal, and the vehicle controller sends the torque command to the motor controller, which brakes or drives the electric vehicle, and receives the acceleration signal fed back by the electric vehicle, and adjusts the torque command sent to the vehicle controller according to the acceleration signal.

[0087] Obviously, in Figure 1 In the control method shown, the control command received by ESP is an acceleration signal. It is difficult to accurately control the speed of the electric vehicle based on the acceleration signal, especially in the scenario where the road load changes greatly. The speed of the electric vehicle is more difficult to accurately control. The speed fluctuates a lot during the driving of the electric vehicle, affecting the driving experience. At the same time, the torque command received by the motor controller is sent by ESP to the vehicle controller and then from the vehicle controller to the motor controller. The control delay of the whole process is long, resulting in a slow response of the motor controller when the electric vehicle is driving on bumpy roads with potholes and stones, sandy land and other off-road terrains, resulting in fluctuations in the speed, affecting the driving experience.

[0088] In view of this, the embodiments of the present application provide a control method for an electric vehicle, a motor controller and an electric vehicle, which actively control the driving motor of the electric vehicle to adjust the torque output by promptly responding to changes in road load after the off-road cruise function of the electric vehicle is started, thereby achieving timely control of the electric vehicle to adjust the vehicle speed to stabilize near a preset speed, thereby improving the stability of the electric vehicle speed and further improving the driving experience.

[0089] See also Figure 2 , Figure 2FIG. 1 is a schematic diagram of an electric vehicle 100 provided in an embodiment of the present application. Figure 2 As shown, the electric vehicle 100 includes a drive system 110, a power battery 120 connected to the drive system 110, and a vehicle controller 130. The drive system 110 is used to drive the electric vehicle 100. The power battery 120 is used to provide electrical energy to the drive system 110. The drive system 110 is used to receive power from the power battery 120 and provide power to the electric vehicle 100. The drive system 110 can also be called a powertrain.

[0090] Optionally, the electric vehicle 100 further includes a braking system 140 , which is used to provide braking force for the electric vehicle 100 when the electric vehicle 100 is in a braking state.

[0091] According to the position of the wheels in the electric vehicle 100, they can be divided into a left front wheel FL, a right front wheel FR, a left rear wheel BL, and a right rear wheel BR. According to the axle, the left front wheel and the right front wheel are coaxial and connected by the front axle. The left rear wheel and the right rear wheel are coaxial and connected by the rear axle. According to the position, the left front wheel and the left rear wheel are on the same side and located on the left side, and the right front wheel and the right rear wheel are on the same side and located on the right side. That is to say, among the four wheels of the electric vehicle 100, the left front wheel and the right front wheel are coaxial wheels with each other, and the left rear wheel and the right rear wheel are coaxial wheels with each other; the left front wheel and the left rear wheel are wheels on the same side, and the right front wheel and the right rear wheel are wheels on the same side.

[0092] The electric vehicle 100 in the embodiment of the present application can be any one of different types of vehicles such as a sedan, a truck, a passenger bus, etc., and can also be a transport device for carrying people or goods such as a tricycle, a two-wheeled vehicle, a train, or other types of vehicles driven by power batteries, which are not limited in the embodiment of the present application. Among them, the vehicle includes but is not limited to a pure electric vehicle (pure electric vehicle / battery electric vehicle, pure EV / batteryEV), a hybrid electric vehicle (hybrid electric vehicle, HEV), a range extended electric vehicle (range extended electric vehicle, REEV), a plug-in hybrid electric vehicle (plug-in hybrid electric vehicle, PHEV), a new energy vehicle (new energy vehicle, NEV), etc.

[0093] The embodiment of the present application does not limit the specific type of the powertrain. As an example and not a limitation, the powertrain can be a centralized powertrain, a hub motor powertrain, or a wheel-side motor powertrain. Among them, the hub motor powertrain is to directly set the motor and the reducer in the wheel rim, eliminating the transmission components such as the half shaft, universal joint, differential, and transmission; the wheel-side motor powertrain is to set the motor on the subframe.

[0094] The power battery 120 in the embodiment of the present application can be a lithium-ion battery, a lithium metal battery, a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen battery, a lithium-sulfur battery, a lithium-air battery or a sodium-ion battery, etc., which is not limited in the present application. In terms of scale, the power battery 120 in the embodiment of the present application can be a single cell, or a battery module or a battery pack, which is not limited in the present application. The power battery 120 can also power other electrical devices in the vehicle, such as the air conditioner in the vehicle, the car player, etc.

[0095] Figure 3 A schematic diagram of the architecture of an electric vehicle 100 provided in an embodiment of the present application is shown.

[0096] See also Figure 3 (a) The electric vehicle 100 is a two-wheel drive vehicle, and the driving system 110 includes a driving motor 111 for two front wheels and a motor controller 121 for the driving motor 111 , and a driving motor 112 for two rear wheels and a motor controller 122 for the driving motor 112 .

[0097] Each drive motor in the drive system 110 is used to provide driving force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a driving state, the motor controller of each drive motor receives a torque signal, receives electric energy from the power battery 120, and controls the corresponding drive motor to output the torque indicated by the torque signal.

[0098] When the electric vehicle 100 is in a driving state, each drive motor in the drive system 110 is used to provide driving force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a driving state, the vehicle controller 130 calculates the torque demand of the electric vehicle and outputs a torque signal to the motor controller of each drive motor. Each motor controller receives a torque signal from the power battery 120 (such as Figure 2 The electric energy (as shown) is used to control the corresponding drive motor to output the torque indicated by the torque signal.

[0099] Continue to refer Figure 3 (a) in the figure, the braking system 140 mainly includes a brake pedal ( Figure 3(a) (not shown), a brake controller 141 and four wheel-end brake devices 142. The brake controller 141 can generate a brake signal based on the opening of the brake pedal, and control one or more of the four wheel-end brake devices 142 to output a braking force to the corresponding wheel based on the indication of the brake signal to prevent the wheel from rotating or the tendency of the wheel to rotate.

[0100] During the braking process of the electric vehicle 100 , the greater the braking force indicated by the braking signal, the greater the braking force output by the wheel-end braking device 142 , and the faster the speed of the electric vehicle 100 decreases.

[0101] When the electric vehicle 100 is in a braking state, the drive system 110 stops driving the wheels to rotate, and the brake system 140 provides braking force to the wheels so that the electric vehicle 100 reduces its speed under the action of the braking force. In the braking state of the electric vehicle 100, each drive motor in the electric vehicle 100 with an energy recovery function can also be used to provide braking force for the electric vehicle 100. Specifically, when the electric vehicle 100 is in a braking state, the vehicle controller 130 receives a braking signal and sends an energy recovery instruction to each motor controller. Each motor controller controls the corresponding drive motor to operate in a power generation state in response to the energy recovery instruction. Each drive motor converts the kinetic energy of the wheels of the electric vehicle into electrical energy and outputs a reverse torque to the wheels of the electric vehicle 100 to provide braking force to the electric vehicle 100.

[0102] The brake in the braking system 140 in the embodiment of the present application may be an electronic hydraulic brake (EHB) or an electronic mechanical brake (EMB) or other types of brakes without limitation.

[0103] Among them, the drive system 110, the brake system 140 and the vehicle controller 130 are communicatively connected via a CAN network, and the embodiments of the present application do not limit the specific communication connection method. For example, the motor controller in the drive system 110 and the vehicle controller 130 can communicate through a private CAN network, the brake controller 141 of the brake system 140 and the vehicle controller 130 can communicate through a public CAN network, and the brake controller 141 and each wheel-end brake device 142 can communicate through another private CAN network. For another example, the vehicle controller 130 can communicate with the motor controller in the drive system 110 and the brake controller 141 in the brake system 140 through the same CAN network.

[0104] See also Figure 3(b) The electric vehicle 100 is a four-wheel drive vehicle, and the drive system 110 includes a drive motor 113 for the left front wheel and a motor controller 123 for the drive motor 113, a drive motor 114 for the right front wheel and a motor controller 124 for the drive motor 114, a drive motor 115 for the left rear wheel and a motor controller 125 for the drive motor 115, and a drive motor 116 for the right rear wheel and a motor controller 126 for the drive motor 116.

[0105] The architecture of the embodiment of the present application is described above. The control method of the electric vehicle provided by the present application will be described below in conjunction with a specific embodiment.

[0106] A control method for an electric vehicle provided in an embodiment of the present application is used to control a driving system of the electric vehicle after an off-road cruise function of the electric vehicle is activated to improve the stability of the electric vehicle speed.

[0107] The control method of the electric vehicle provided in the embodiment of the present application includes the following steps.

[0108] At the first moment t1, the opening of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening and the opening of the brake pedal is less than the preset brake pedal opening, and the drive motor of the electric vehicle is controlled to output torque so that the electric vehicle travels at a preset speed.

[0109] In the embodiment of the present application, the specific values ​​of the preset accelerator pedal opening, the preset brake pedal opening and the preset vehicle speed are not limited. Here, the output torque of the driving motor of the electric vehicle is controlled as torque.

[0110] The preset brake pedal opening and the preset accelerator pedal opening are both relatively small values, such as 5%, 8%, 10%, etc.

[0111] In an embodiment of the present application, if the opening of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening and the opening of the brake pedal is less than the preset brake pedal opening, it can be considered that the user has not operated the brake pedal and the accelerator pedal or has not operated the brake pedal or the accelerator pedal significantly. At this time, the speed of the electric vehicle is controlled by the intelligent driving controller, not by the user operating the brake pedal and the accelerator pedal.

[0112] The preset speed may be the default speed of the off-road cruise function or the speed set by the user. The user may set the speed through the central control screen or through a mobile terminal associated with the electric vehicle. The specific setting method is not limited in the embodiment of the present application. The preset speed may be a smaller value, such as 10kph, 12kph, 15kph, etc.

[0113] By automatically controlling the drive motor output torque of the electric vehicle to make the electric vehicle move when the opening of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening and the opening of the brake pedal is less than the preset brake pedal opening, it is achieved that in complex off-road terrain, the electric vehicle can automatically control the driving speed without the driver operating the accelerator pedal or brake pedal of the electric vehicle, thereby reducing the user's operating burden and helping drivers with insufficient driving experience to pass through off-road terrain.

[0114] At a second time t2 after the first time t1, the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first time t1, and the drive motor is actively controlled to adjust the torque output.

[0115] It can be known that the road load refers to the interaction force between the wheels of the electric vehicle and the road surface when the electric vehicle is driving on the road, and is the resistance of the electric vehicle during driving.

[0116] The road load change at the second moment t2 may be a decrease in road load, such as entering a bumpy road or entering sand.

[0117] The road load change at the second moment t2 may also be an increase in the road load, such as from sandy land to flat land, from sandy land to a bumpy road, etc.

[0118] At the second moment t2, actively controlling the drive motor to adjust the torque output means actively controlling the torque output of the drive motor of the wheel whose road load in contact with the road surface changes relative to the first moment t1. After actively controlling the drive motor to adjust the torque output, the speed of the electric vehicle is the first speed, and the difference between the first speed and the preset speed is less than the preset difference. The preset difference is a smaller value, that is, the first speed is close to the preset speed.

[0119] In one implementation, actively controlling the drive motor to adjust the torque output includes: actively controlling the drive motor to reduce the torque output and actively controlling the drive motor to increase the torque output.

[0120] The active control here means that the electric vehicle's motor controller controls the drive motor of the wheel to adjust the torque output in response to changes in the road load of the wheel, rather than passively controlling the drive motor to adjust the torque output in response to control instructions from the vehicle controller or other vehicle controllers, thereby improving the electric vehicle's response speed to changes in road load.

[0121] In this embodiment, when the off-road cruise function is enabled in the electric vehicle, the torque output of the drive motor is actively controlled to adjust according to the change in the road load of the road surface contacted by the wheels of the electric vehicle, rather than responding to the instruction of the torque signal sent by the electronic stability program through the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to the change in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by the complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0122] In one embodiment, at the second moment t2, the road load increases, and the drive motor is actively controlled to increase the torque output.

[0123] As the road load increases, greater torque is required to overcome the road load. In order to stabilize the vehicle speed at the preset speed, the drive motor is actively controlled to increase the torque output.

[0124] See also Figure 4 , Figure 4 1 shows a schematic diagram of a driving scene of an electric vehicle 100. Figure 4 At the first moment t1, the electric vehicle is at position 1, and the electric vehicle is traveling in Figure 4 On the bumpy road surface shown in 410 , the driving motor of the electric vehicle is controlled to output torque so that the electric vehicle travels at a preset speed.

[0125] At the second moment t2, the electric vehicle travels to position 2 and starts to drive onto a flat road (such as a cement road, asphalt road, etc.). The road load of the road surface contacted by the two front wheels increases relative to the road load of the road surface contacted by the two front wheels at the first moment t1, and the drive motors of the two front wheels are actively controlled to increase the torque output.

[0126] For ease of understanding, the electric vehicle 100 is traveling on a road such as Figure 4 Take the scenario shown as an example, Figure 5 A schematic diagram of a control method for an electric vehicle 100 is shown.

[0127] At the first time t1, the driving motors of the four wheels are controlled to output torque to the four wheels so that the electric vehicle travels at a preset vehicle speed V1.

[0128] At the second moment t2, the road load of the road surface contacted by the two front wheels of the electric vehicle 100 increases relative to the road load of the road surface contacted by the two front wheels at the first moment t1, and the road load of the road surface contacted by the two rear wheels remains unchanged. The drive motors of the two front wheels are actively controlled to increase the torque output, and the drive motors of the two rear wheels maintain the torque output at the first moment t1.

[0129] In the whole process, the opening degree of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening degree K1 and the opening degree of the brake pedal is less than the preset brake pedal opening degree K2.

[0130] In this embodiment, the road load acts as resistance during vehicle driving. When the road load increases, the torque output of the drive motor needs to increase to maintain the stability of the electric vehicle speed. By actively controlling the drive motor to increase the torque output when the road load increases, the torque output of the drive motor is controlled in a timely manner to stabilize the vehicle speed near the preset speed, thereby improving the speed fluctuation problem caused by complex off-road terrain conditions, improving the stability of the electric vehicle speed, and improving the driving experience.

[0131] As the road load increases, the speed of the electric vehicle is affected more by the road load, and a greater output torque of the drive motor is required to maintain the stability of the electric vehicle speed.

[0132] Thus, in one embodiment, at the second moment t2, the increase in the road load is the first increase, and the torque output by the actively controlled drive motor is the first torque; at the second moment, the increase in the road load is the second increase, and the torque output by the actively controlled drive motor is the second torque; the first increase is greater than the second increase, and the first torque is greater than the second torque.

[0133] In the embodiment of the present application, there is no limitation on the specific values ​​of the first increase amount, the second increase amount, the first torque and the second torque. The first torque and the second torque are both smaller than the torque corresponding to the road adhesion capacity to prevent the electric vehicle from slipping.

[0134] In this embodiment, the road load acts as resistance during vehicle driving. When the increase in the road load is large, the torque output by the drive motor is actively controlled to be larger, and when the increase in the road load is small, the torque output by the drive motor is actively controlled to be smaller. This allows the torque output by the drive motor to overcome the road load while stabilizing the vehicle speed near a preset speed during off-road cruising of the electric vehicle, thereby improving the speed stability of the electric vehicle during off-road cruising and enhancing the driving experience.

[0135] Thus, in one embodiment, at the second time t2, the greater the increase in the road load, the greater the increase in the torque output by the active control drive motor.

[0136] In this embodiment, the road load acts as resistance during vehicle driving. The greater the increase in the road load, the greater the resistance during the driving of the electric vehicle. The increase in the torque output by the drive motor is increased by actively controlling the increase in the road load, so that during the off-road cruising of the electric vehicle, the increase in the torque output by the drive motor can be flexibly controlled according to the increase in the road load, so that the torque output by the drive motor can overcome the road load and stabilize the vehicle speed near the preset speed during the off-road cruising, thereby improving the stability of the electric vehicle speed during the off-road cruising and improving the driving experience.

[0137] In one embodiment, at the second moment t2, the increased torque output by the drive motor is actively controlled to be less than or equal to a preset torque; the smaller the adhesion coefficient of the road surface, the smaller the preset torque.

[0138] Among them, the adhesion coefficient determines the road adhesion capacity, and the preset torque is the torque corresponding to the road adhesion capacity.

[0139] In this embodiment, by setting a preset torque and actively controlling the increased torque output by the drive motor to be less than or equal to the preset torque, wheel slippage during off-road cruising is avoided, thereby improving driving safety. In addition, the preset torque decreases as the adhesion coefficient decreases, so that the electric vehicle can still avoid wheel slippage in the case of complex off-road terrain conditions, thereby improving the driving experience.

[0140] In yet another embodiment, at the second moment t2 , the road load decreases, and the drive motor is actively controlled to reduce the torque output.

[0141] See also Figure 6 , Figure 6 1 shows a schematic diagram of a driving scene of an electric vehicle 100. Figure 6 In the example, at a first moment t2, the electric vehicle is located at position 1 and is traveling on a flat road. The drive motor of the electric vehicle is controlled to output torque so that the electric vehicle travels at a preset speed.

[0142] At the second moment t2, the electric vehicle drives to position 2. Figure 6 In the bumpy road shown in 610 , the road load of the road surface contacted by the two front wheels is reduced compared with the road load of the road surface contacted by the two front wheels at the first moment t1 , and the drive motor is actively controlled to reduce the torque output.

[0143] For ease of understanding, the electric vehicle 100 is traveling on a road such as Figure 6 Take the scenario shown as an example, Figure 7 A schematic diagram of a control method for an electric vehicle 100 is shown.

[0144] At the first time t1, the driving motors of the four wheels are controlled to output torque to the four wheels so that the electric vehicle travels at a preset vehicle speed V1.

[0145] At the second moment t2, the road load of the road surface contacted by the two front wheels of the electric vehicle 100 is reduced relative to the road load of the road surface contacted by the two front wheels at the first moment t1, and the road load of the road surface contacted by the two rear wheels remains unchanged. The drive motor is actively controlled to reduce the torque output, and the drive motors of the two rear wheels maintain the torque output at the first moment t1.

[0146] In the whole process, the opening degree of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening degree K1 and the opening degree of the brake pedal is less than the preset brake pedal opening degree K2.

[0147] In this embodiment, the road load acts as resistance during vehicle driving. When the road load is reduced, the torque output by the drive motor needs to be reduced to maintain the stability of the electric vehicle speed. By actively controlling the drive motor to reduce the torque output when the road load is reduced, the torque output of the drive motor is controlled in a timely manner to stabilize the vehicle speed near the preset speed, thereby improving the speed fluctuation problem caused by the complex off-road terrain conditions, improving the stability of the electric vehicle speed, and improving the driving experience.

[0148] During off-road cruising, if the user reduces the desired speed of the electric vehicle (preset speed), the present application also provides a control method for the electric vehicle for adjusting the speed to stabilize at the reduced preset speed after the user reduces the preset speed. The method includes the following steps.

[0149] At a third moment t3 after the first moment t1 , the preset vehicle speed decreases, and the drive motor is controlled to output a reverse torque and / or the brake system of the electric vehicle is actively controlled to output a braking force.

[0150] The torque direction of the reverse torque is opposite to the rotation direction of the wheels of the electric vehicle. The reverse torque indicates the torque without the torque direction, which is an absolute value.

[0151] In one embodiment, controlling the speed of the electric vehicle to decrease to a preset speed after the decrease can brake the electric vehicle by actively controlling the drive motor to output a reverse torque or controlling the braking system to output a braking force.

[0152] In another embodiment, the maximum reverse torque that the drive motor can output is determined by the electric drive capability of the drive motor. When the maximum reverse torque is unable to brake the vehicle and reduce the speed of the electric vehicle to a reduced preset speed, the braking system outputs a braking force, and the maximum reverse torque output by the drive motor and the braking force output by the braking system jointly brake the electric vehicle.

[0153] In one embodiment, the control method also includes: at a third moment t3, the reduction in the preset vehicle speed is a first reduction, the reverse torque output by the drive motor is controlled to be the first reverse torque, and / or the braking force output by the braking system of the electric vehicle is controlled to be the first braking force; at a second moment, the reduction in the preset vehicle speed is a second reduction, the reverse torque output by the drive motor is controlled to be the second reverse torque, and / or the braking force output by the braking system of the electric vehicle is controlled to be the second braking force; the first reduction is greater than the second reduction, the first reverse torque is greater than the second reverse torque, and the first braking force is greater than the second braking force.

[0154] In this embodiment, a greater reduction in the preset vehicle speed causes a greater amount of braking to be required to adjust the electric vehicle to travel at the reduced preset vehicle speed. By controlling the reverse torque output by the drive motor and / or the braking force output by the braking system to be greater when the preset vehicle speed is reduced by a greater amount, and controlling the reverse torque output by the drive motor and / or the braking force output by the braking system to be smaller when the preset vehicle speed is reduced by a smaller amount, it is achieved that during off-road cruising of the electric vehicle, the electric vehicle can always travel at the speed desired by the user even when the speed desired by the user is reduced, thereby improving the driving experience.

[0155] In an embodiment of the first aspect, the control method also includes: at the third moment t3, the greater the reduction in the preset vehicle speed, the greater the increase in the reverse torque output by the drive motor and / or the increase in the braking force output by the braking system of the electric vehicle.

[0156] In this embodiment, the greater the reduction in the preset vehicle speed, the greater the braking required to adjust the electric vehicle to travel at the reduced preset vehicle speed. By controlling the increase in the reverse torque output by the drive motor and / or the increase in the braking force output by the braking system of the electric vehicle, the increase in the reverse torque and / or braking force output by the drive motor can be flexibly controlled according to the reduction in the preset vehicle speed during off-road cruising of the electric vehicle, thereby achieving the goal that during off-road cruising of the electric vehicle, the electric vehicle can always travel at the speed expected by the user even if the speed expected by the user is reduced, thereby improving the driving experience.

[0157] At a fourth moment t4 after the third moment t3, the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the third moment, and the drive motor is actively controlled to adjust the reverse torque output and / or the braking system of the electric vehicle is actively controlled.

[0158] At the fourth time t4, actively controlling the drive motor to adjust the torque output refers to actively controlling the torque output and / or braking force output of the drive motor of the wheel whose road load in contact with the road surface changes at the third time t3.

[0159] In one embodiment, actively controlling the drive motor to adjust the reverse torque output and / or actively controlling the electric vehicle's braking system to adjust the braking force output includes: actively controlling the drive motor to increase the reverse torque output and / or actively controlling the electric vehicle's braking system to increase the braking force output, and actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the electric vehicle's braking system to reduce the braking force output.

[0160] In this embodiment, the preset speed reduction requires braking of the electric vehicle to reduce the adjusted speed to the preset speed after the reduction, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, thereby improving the driving experience. In the process of adjusting the electric vehicle to travel at the preset speed after the reduction, by actively controlling the drive motor to adjust the reverse torque output and / or actively controlling the brake system of the electric vehicle to adjust the braking force output according to the change of the road load of the road surface contacted by the wheels of the electric vehicle, rather than responding to the torque signal or brake signal issued by the electronic stability program through the vehicle controller to control the output, it is realized that the torque output of the drive motor and / or the braking force output of the brake system are controlled in time to the change of the road load so that the speed is reduced to the preset speed after the reduction at a stable deceleration, thereby improving the driving experience. At the same time, the braking method of the electric vehicle includes controlling the drive motor to output the reverse torque and controlling the brake system of the electric vehicle to output the braking force, thereby improving the braking flexibility, and when the reverse torque output by controlling the drive motor is insufficient to brake the electric vehicle, the braking can be achieved by controlling the brake system of the electric vehicle to output the braking force to improve the stability of the deceleration of the electric vehicle.

[0161] In one embodiment, at the fourth moment t4, the road load increases, and the drive motor is actively controlled to increase the reverse torque output and / or the braking system of the electric vehicle is actively controlled to increase the braking force output.

[0162] In this case, the driving scene graph corresponding to the fourth moment t4 can be as follows: Figure 4 shown.

[0163] For ease of understanding, the electric vehicle 100 is traveling on a road such as Figure 4 Take the scenario shown as an example, Figure 8 A schematic diagram of a control method for an electric vehicle 100 is shown.

[0164] At the third moment t3, the drive motor is controlled to output a reverse torque and / or the brake system of the electric vehicle is actively controlled to output a braking force to reduce the speed of the electric vehicle.

[0165] At the fourth moment t4, the road load of the road surface contacted by the two front wheels of the electric vehicle 100 increases relative to the road load of the road surface contacted by the two front wheels at the third moment t3, and the road load of the road surface contacted by the two rear wheels remains unchanged. The drive motor is actively controlled to increase the reverse torque output to the two front wheels and / or the braking system is actively controlled to increase the braking force output to the two front wheels, and the two rear wheels maintain the torque output and braking force output at the third moment t3.

[0166] In the whole process, the opening degree of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening degree K1 and the opening degree of the brake pedal is less than the preset brake pedal opening degree K2.

[0167] In this embodiment, the resistance when braking the electric vehicle increases as the road load increases. By actively controlling the drive motor to increase the reverse torque output and / or actively controlling the brake system of the electric vehicle to increase the braking force output when the road load increases, timely response to the increase in road load is achieved to control the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0168] As the road load increases, the deceleration of the electric vehicle is affected more by the road load, and a greater reverse torque and / or braking force needs to be output to maintain the speed of the electric vehicle at a stable deceleration.

[0169] Thus, in one embodiment, at the fourth moment t4, the increase in the road load is the first increase, the reverse torque output by the actively controlled drive motor is the first reverse torque, and / or the braking force output by the actively controlled braking system of the electric vehicle is the first braking force; at the second moment, the increase in the road load is the second increase, the reverse torque output by the actively controlled drive motor is the second reverse torque, and / or the braking force output by the actively controlled braking system of the electric vehicle is the second braking force; the first increase is greater than the second increase, the first torque is greater than the second torque, and the first braking force is greater than the second braking force.

[0170] In this embodiment, the road load acts as resistance during vehicle driving. When the increase in the road load is large, the reverse torque output by the drive motor and / or the braking force output by the brake system are actively controlled to be larger, and when the increase in the road load is small, the reverse torque output by the drive motor and / or the braking force output by the brake system are actively controlled to be smaller. This achieves timely response to different increases in the road load by controlling the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed at a stable deceleration rate, thereby improving the driving experience.

[0171] In yet another embodiment, at the fourth moment t4, the greater the increase in the road load is, the greater the increase in the reverse torque output by the active control drive motor and / or the increase in the braking force output by the brake system is.

[0172] In this embodiment, the road load acts as resistance during vehicle driving. The greater the increase in the road load, the greater the resistance during the driving of the electric vehicle. The increase in the torque output by the drive motor is increased by actively controlling the increase in the road load, so that during the off-road cruising of the electric vehicle, the increase in the torque output by the drive motor can be flexibly controlled according to the increase in the road load, thereby achieving timely response to different increases in the road load and controlling the torque output of the drive motor and / or the braking force output of the braking system to reduce the vehicle speed to the preset speed at a stable deceleration, thereby improving the driving experience.

[0173] In one embodiment, at the fourth moment, the road load decreases, the drive motor is actively controlled to reduce the reverse torque output and / or the braking system of the electric vehicle is actively controlled to reduce the braking force output.

[0174] In this case, the driving scene graph corresponding to the fourth moment t4 can be as follows: Figure 6 shown.

[0175] For ease of understanding, the electric vehicle 100 is traveling on a road such as Figure 6 Take the scenario shown as an example, Fig. 9 A schematic diagram of a control method for an electric vehicle 100 is shown.

[0176] At the third moment t3, the drive motor is controlled to output a reverse torque and / or the brake system of the electric vehicle is actively controlled to output a braking force to reduce the speed of the electric vehicle.

[0177] At the fourth moment t4, the road load of the road surface contacted by the two front wheels of the electric vehicle 100 is reduced relative to the road load of the road surface contacted by the two front wheels at the third moment t3, and the road load of the road surface contacted by the two rear wheels remains unchanged. The drive motor is actively controlled to reduce the reverse torque output to the two front wheels and / or the braking system is actively controlled to reduce the braking force output to the two front wheels, and the two rear wheels maintain the torque output and braking force output at the third moment t3.

[0178] In the whole process, the opening degree of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening degree K1 and the opening degree of the brake pedal is less than the preset brake pedal opening degree K2.

[0179] In this embodiment, the resistance when braking the electric vehicle is reduced when the road load is reduced. By actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the brake system of the electric vehicle to reduce the braking force output when the road load is reduced, timely response to the reduction of the road load is achieved to control the torque output of the drive motor and / or the braking force output of the brake system so that the vehicle speed is reduced to the preset vehicle speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0180] In one embodiment, in the control method provided in the embodiment of the present application, during off-road cruising (for example, at the second moment t2 and the third moment t4), the implementation method of actively controlling the drive motor to adjust the torque output may include: actively controlling the drive motor to adjust the torque output according to the motor torque signal and / or the resolver signal from the resolver sensor.

[0181] Among them, the resolver signal indicates the motor speed, and the motor torque signal indicates the motor torque output by the drive motor. Both the resolver signal and the motor torque signal are signals that can be directly obtained by the motor controller.

[0182] In one embodiment, the resolver signal and / or the motor torque signal from the resolver sensor can be input into the load observer, and the load observer outputs the road load at the second moment or the fourth moment according to the motor speed indicated by the resolver signal and / or the motor torque indicated by the motor torque signal, and then actively controls the drive motor to adjust the torque output according to the change of the road load at the second moment or the fourth moment. The specific type of the load observer is not limited in the embodiment of the present application.

[0183] If the motor speed indicated by the resolver signal increases, it is considered that the road load decreases; if the motor speed indicated by the resolver signal decreases, it is considered that the road load increases.

[0184] In this embodiment, the resolver signal and the motor torque signal are signals that can be directly obtained. The motor speed indicated by the resolver signal changes with the change of the road load. By actively controlling the drive motor to adjust the torque output according to the resolver signal and / or the motor torque signal from the resolver sensor, it is achieved to respond to the change of the road load in a timely manner to control the torque output of the drive motor to stabilize the vehicle speed near the preset vehicle speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience. At the same time, the resolver signal and the motor torque signal are higher in accuracy and better in stability than the wheel speed signal. According to the resolver signal and / or the motor torque signal, the change of the road load can be accurately identified, thereby improving the accuracy of the drive motor to adjust the torque output control.

[0185] The following takes the example of actively controlling the drive motor to adjust the torque output according to the resolver signal and / or the motor torque signal from the resolver sensor at the second moment t2 and the fourth moment t4 as an example to introduce some details of the implementation method of actively controlling the drive motor to adjust the torque output. Similar methods can be used for other moments, such as moments after the fourth moment t4.

[0186] In one embodiment, at the second moment t2, the motor speed indicated by the resolver signal from the resolver sensor decreases, and the drive motor is actively controlled to increase the torque output; at the second moment, the motor speed indicated by the resolver signal from the resolver sensor increases, and the drive motor is actively controlled to reduce the torque output.

[0187] In this embodiment, a decrease in the motor speed indicated by the resolver signal indicates an increase in the road load. By actively controlling the drive motor to increase the torque output, a timely response to the increase in the road load is achieved by controlling the torque output of the drive motor to stabilize the vehicle speed near the preset speed. An increase in the motor speed indicated by the resolver signal indicates a decrease in the road load. By actively controlling the drive motor to reduce the torque output, a timely response to the change in the road load is achieved by controlling the torque output of the drive motor to stabilize the vehicle speed near the preset speed. This improves the problem of vehicle speed fluctuations caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0188] In one embodiment, at the second moment t2, the greater the rate of decrease of the motor speed indicated by the resolver signal from the resolver sensor, the greater the increase in the torque output by the actively controlled drive motor; at the second moment, the greater the rate of increase of the motor speed indicated by the resolver signal from the resolver sensor, the greater the decrease in the torque output by the actively controlled drive motor.

[0189] In this embodiment, the greater the rate of decrease of the motor speed indicated by the rotary signal, the greater the increase in the road load, and the more obvious the fluctuation of the electric vehicle speed. The greater the increase in the torque output by the active control drive motor, the greater the increase in the torque output by the drive motor increases with the increase in the road load, so that the embodiment of the present application can improve the speed fluctuation problem under different road load increases and stabilize the vehicle speed near the preset speed. The greater the rate of increase of the motor speed indicated by the rotary signal, the greater the decrease in the road load, and the more obvious the fluctuation of the electric vehicle speed. The greater the decrease in the torque output by the active control drive motor, the greater the decrease in the torque output by the drive motor increases with the increase in the road load decrease, so that the embodiment of the present application can improve the speed fluctuation problem under different road load decreases and stabilize the vehicle speed near the preset speed, thereby improving the driving experience.

[0190] In one embodiment, at the fourth moment t4, the motor speed indicated by the resolver signal from the resolver sensor decreases, and the drive motor is actively controlled to increase the reverse torque output and / or the braking system is actively controlled to increase the braking force output; at the second moment, the motor speed indicated by the resolver signal from the resolver sensor increases, and the drive motor is actively controlled to reduce the reverse torque output and / or the braking system of the electric vehicle is actively controlled to reduce the braking force output.

[0191] In this embodiment, a decrease in the motor speed indicated by the resolver signal indicates an increase in the road load. By actively controlling the drive motor to increase the reverse torque output and / or actively controlling the braking system of the electric vehicle to increase the braking force output, it is possible to respond promptly to the increase in the road load by controlling the torque output of the drive motor and / or the braking force output of the braking system so that the vehicle speed is reduced to a preset speed after the reduction at a stable deceleration rate. An increase in the motor speed indicated by the resolver signal indicates a decrease in the road load. By actively controlling the drive motor to reduce the reverse torque output and / or actively controlling the braking system of the electric vehicle to reduce the braking force output, it is possible to respond promptly to the decrease in the road load by controlling the torque output of the drive motor and / or the braking force output of the braking system so that the vehicle speed is reduced to a preset speed after the reduction at a stable deceleration rate, thereby improving the driving experience.

[0192] In one embodiment, at the fourth moment t4, the greater the decrease rate of the motor speed indicated by the resolver signal from the resolver sensor, the greater the increase in the reverse torque output by the actively controlled drive motor and / or the increase in the braking force output by the actively controlled brake system; at the second moment, the greater the increase rate of the motor speed indicated by the resolver signal from the resolver sensor, the greater the decrease in the reverse torque output by the actively controlled drive motor and / or the decrease in the braking force output by the actively controlled brake system.

[0193] In this embodiment, the greater the rate of decrease of the motor speed indicated by the rotary signal, the greater the increase in the road load, the more obvious the fluctuation of the electric vehicle speed, the greater the increase in the reverse torque output by the active control drive motor and / or the increase in the braking force output by the active control brake system, the greater the increase in the reverse torque and / or the increase in the braking force increases with the increase in the road load, so that under different conditions of the increase in the road load, the embodiment of the present application can reduce the vehicle speed to the preset speed after the reduction at a stable deceleration. The greater the rate of increase of the motor speed indicated by the rotary signal, the greater the decrease in the road load, the more obvious the fluctuation of the electric vehicle speed, the greater the decrease in the reverse torque output by the active control drive motor and / or the decrease in the braking force output by the active control brake system, the greater the decrease in the reverse torque and / or the decrease in the braking force increases with the increase in the decrease in the road load, so that under different conditions of the decrease in the road load, the embodiment of the present application can reduce the vehicle speed to the preset speed after the reduction at a stable deceleration, thereby improving the driving experience.

[0194] In one embodiment, at a first moment t1, a torque signal is received and the drive motor is controlled to output the torque indicated by the torque signal; at a second moment, the drive motor is actively controlled to output a torque greater than or less than the torque indicated by the torque signal.

[0195] The torque signal is a signal sent by the vehicle controller.

[0196] The torque signal at the first moment can be a torque signal obtained by the vehicle controller based on the speed command sent by the intelligent driving controller, or it can be a torque obtained by the vehicle controller based on the speed command and the resolver signal, and the speed indicated by the speed command is a preset vehicle speed.

[0197] At the second moment, the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the torque output by the control drive motor is different from the torque indicated by the torque signal.

[0198] In this embodiment, when the road load of the road surface contacted by any wheel of the electric vehicle changes, the torque output of the drive motor is actively controlled to be greater than or less than the torque indicated by the torque signal. That is to say, when the road load changes, the drive motor can be actively controlled to adjust the torque output, rather than responding to the torque signal indicated by the electronic stability program through the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to the change in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0199] Similarly, at the third moment t3, the torque signal is received and the drive motor is controlled to output the torque indicated by the torque signal and / or the braking signal is received and the braking system is controlled to output the braking force indicated by the braking signal; at the fourth moment, the reverse torque output by the drive motor is actively controlled to be greater than or less than the absolute value of the torque indicated by the torque signal and / or the braking force output by the braking system is controlled to be greater than or less than the braking force indicated by the braking signal.

[0200] At the fourth moment t3, the torque indicated by the torque signal is a negative value, and the reverse torque is an absolute value, so the absolute value of the torque indicated by the torque signal and the reverse torque are compared.

[0201] In one embodiment, at a first moment t1, a speed signal is received and the drive motor is controlled to output torque so that the electric vehicle travels at a preset speed indicated by the speed signal; at a second moment t2, a speed signal is received and the drive motor is actively controlled to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal.

[0202] Among them, the speed signal is the signal sent by the intelligent driving controller.

[0203] At the second moment, the purpose of actively controlling the drive motor to adjust the torque output is to make the electric vehicle travel at a preset vehicle speed indicated by the speed signal.

[0204] In this embodiment, the purpose of controlling the output torque of the drive motor at the first moment and the second moment is to automatically control the electric vehicle to travel at the speed indicated by the speed signal. The road load of the road surface contacted by any wheel of the electric vehicle changes, and the torque output is adjusted by actively controlling the drive motor to make the electric vehicle travel at the preset speed indicated by the speed signal, so as to achieve timely response to the change of road load and control the torque output of the drive motor to stabilize the vehicle speed at the preset speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience.

[0205] During off-road cruising, there is a long control delay in the entire process of judging whether the wheels of the electric vehicle are slipping, and responding to and controlling the drive motor to adjust the torque output when the wheels slip. This results in an inability to deal with the wheel slip problem in a timely manner, and there is a great safety risk during off-road cruising.

[0206] See also Fig.10 , Fig.10 A schematic diagram of a control method for an electric vehicle is shown. Fig.12 During the driving process of the electric vehicle, ESP determines whether the wheels of the electric vehicle are slipping by receiving the wheel speed signal sent by the wheel speed sensor. If the wheels of the electric vehicle are slipping, ESP intervenes in the torque intervention to parse the torque command, and then the vehicle controller sends the torque command to the motor controller, and the motor controller controls the electric vehicle in response to the torque command.

[0207] Obviously, in Fig.10 In the control method shown, there is a certain delay in obtaining the wheel speed signal. The wheel speed signal is used to determine whether the wheel is slipping, resulting in ESP being unable to determine whether the wheel is slipping in time. The torque command generated after ESP determines that the wheel is slipping needs to be sent to the motor controller through the vehicle controller. The control delay in the whole process is long, and the wheel slip problem cannot be handled in time, resulting in a greater safety risk during off-road cruising.

[0208] In view of this, the control method of the electric vehicle provided in the embodiment of the present application is also used to quickly determine whether the wheels of the electric vehicle are slipping during off-road cruising of the electric vehicle, and to promptly respond to control the drive motor to adjust the torque output when the wheels are slipping, thereby improving the driving safety of the electric vehicle. The method includes the following steps.

[0209] After the first moment t1, any wheel of the electric vehicle slips, and the drive motor is actively controlled to reduce the torque output; any wheel slip of the electric vehicle means that the slip rate or slip rate of any wheel is greater than a preset value.

[0210] The specific value of the preset value is not limited in the embodiment of the present application, and may be 25%, 30%, 35%, etc. Wherein, if any wheel of the electric vehicle slips, it can be considered that the torque or reverse torque output by the drive motor is greater than the torque corresponding to the road adhesion capacity.

[0211] In one implementation, whether the wheels of the electric vehicle are slipping is determined based on resolver signals from four resolver sensors.

[0212] The reduction of the torque output here may be the reduction of the torque output at the second moment t2, or the reduction of the reverse torque output at the fourth moment t4.

[0213] For ease of understanding, Fig.11 A schematic diagram of a control method for an electric vehicle 100 is shown.

[0214] exist Fig.11 In the embodiment, the motor controller receives the resolver signal sent by the resolver sensor and calculates the slip rate or slip ratio of the four wheels of the electric vehicle according to the resolver signal. When the slip rate or slip ratio of any wheel of the electric vehicle is greater than a preset value, the drive motor is actively controlled to reduce the torque output.

[0215] compared to Fig.10 A control method for an electric vehicle is shown. The control method for an electric vehicle provided in an embodiment of the present application can promptly detect whether the wheels of the electric vehicle are slipping, and after detecting that the wheels are slipping, promptly control the drive motor to reduce the torque output to reduce the slip rate or slip rate, thereby reducing the control delay and ensuring the driving safety of the electric vehicle.

[0216] In this embodiment, when any wheel of the electric vehicle slips, the torque output is reduced by actively controlling the drive motor rather than controlling the drive motor to adjust the torque output in response to the indication of the torque signal. In this way, the torque output of the drive motor is controlled in a timely manner in response to wheel slip to improve driving safety.

[0217] During off-road cruising, there may be obstacles or other vehicles around the electric vehicle, and there may be a risk of collision between the electric vehicle and the obstacles or other vehicles around it.

[0218] Based on this, in one embodiment, during the driving process of the electric vehicle after the off-road cruise function of the electric vehicle is activated, when the distance between the electric vehicle and an obstacle or the distance between the electric vehicle and other vehicles is less than a preset distance, the drive motor is controlled to stop rotating.

[0219] The obstacle may be any object with a collision risk, such as an animal or a tree. The preset distance may be the distance from when the drive motors controlling the four wheels stop rotating to when the drive motors stop rotating, and when the drive motors stop rotating, there will be no collision with obstacles or other vehicles.

[0220] In this embodiment, a preset distance is set to avoid the situation where the distance between the electric vehicle and an obstacle or other vehicle is too small during the driving of the electric vehicle after the off-road cruise function of the electric vehicle is activated. The electric vehicle is continued to be controlled to prevent collision with the obstacle or other vehicle, thereby improving driving safety.

[0221] The embodiment of the present application provides a motor controller for an electric vehicle 100 , and the motor controller is used to execute the control method of the electric vehicle provided in the above embodiment.

[0222] According to the control method of the electric vehicle provided by the above embodiment, the motor controller is specifically used for: at the first moment t1, when the opening of the accelerator pedal of the electric vehicle is less than the preset accelerator pedal opening and the opening of the brake pedal is less than the preset brake pedal opening, controlling the drive motor to output torque so that the electric vehicle travels at a preset speed; at the second moment t2 after the first moment, when the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, actively controlling the drive motor to adjust the torque output and other operations. For more detailed descriptions of the control methods, please refer to the relevant description above.

[0223] In this embodiment, at the second moment, the motor controller directly controls the drive motor to adjust the torque output, rather than controlling the drive motor to adjust the torque output in response to the torque signal issued by the electronic stability program through the vehicle controller, so that the operation of the motor controller and the drive motor is decoupled from the vehicle controller, so that after the road load changes, the motor controller can actively control the drive motor of the electric vehicle to adjust the torque output and promptly respond to the road load change to stabilize the vehicle speed at the preset speed, thereby improving the stability of the electric vehicle speed during off-road cruising, and thereby improving the driving experience.

[0224] In one embodiment, the motor controller is also used to receive a speed signal, and the motor controller is specifically used to: at a first moment, control the drive motor to output torque so that the electric vehicle travels at a preset speed indicated by the speed signal; at a second moment, actively control the drive motor to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal.

[0225] For ease of understanding, the following Fig.12 , Fig.13 and Fig.14 The motor controller provided in the embodiment of the present application is described in detail.

[0226] Take four-wheel drive models as an example. Fig.12 1 shows a schematic diagram of a motor controller of an electric vehicle 100. Fig.12 In the process, the intelligent driving controller sends speed signals to the motor controller 1 of the drive motor of the left front wheel, the motor controller 2 of the drive motor of the right front wheel, the motor controller 3 of the drive motor of the left rear wheel and the motor controller 4 of the drive motor of the right rear wheel. The four motor controllers send torque instructions to the four drive motors and / or send braking instructions to the braking system in response to the speed signals, and periodically adjust the torque indicated by the torque instructions sent to the four drive motors and / or the braking force indicated by the braking instructions sent to the braking system according to the rotary transformer signals fed back by the drive motors.

[0227] Fig.13 1 shows a schematic diagram of a motor controller of an electric vehicle 100. Fig.13 The specific process of adjusting the torque indicated by the torque command sent to the four drive motors and / or the braking force indicated by the braking command sent to the braking system by the four motor controllers is shown in FIG.

[0228] like Fig.13 As shown, the motor controller includes a command conversion module, a motor speed control module, a load observer, a road adhesion observation module and a torque arbitration module.

[0229] The intelligent driving controller sends the speed signal to the motor controller, and the command conversion module of the motor controller converts the speed signal into a motor speed signal. The motor speed signal and the resolver signal are then input into the motor speed control module to obtain the speed loop torque output by the motor speed control module. Subsequently, the speed loop torque is sent to the torque arbitration module.

[0230] At the same time, the resolver signal and the motor torque signal are input into the load observer to obtain the load torque corresponding to the road load output by the load observer, and the load torque is sent to the torque arbitration module.

[0231] In addition, the resolver signal is sent to the road adhesion observation module to obtain the road adhesion torque output by the road adhesion observation module, and the road adhesion torque is sent to the torque arbitration module.

[0232] Finally, the torque arbitration module combines the speed loop torque, the load torque and the road adhesion torque to generate a torque command and / or a braking command.

[0233] In one implementation, the braking command may be sent to an electronic stability program, and then sent by the electronic stability program to a braking system. The braking system controls the wheel-end braking device to brake the vehicle in response to the braking command.

[0234] See also Fig.14 , Fig.14 FIG. 1 shows an operation flow chart of a motor controller of an electric vehicle 100. Fig.14 The specific process of the torque arbitration module inside the motor controller generating a torque command and / or a braking command is shown in FIG.

[0235] like Fig.14 As shown, S1401, receiving a signal input, wherein the input signal at least includes an off-road cruise module enabling signal.

[0236] S1402: Determine whether off-road cruise is enabled.

[0237] If not, execute S1403 and enter human driving torque control.

[0238] If so, execute S1404 to calculate the torque indicated by the torque command.

[0239] The torque indicated by the torque command = speed loop torque + load torque.

[0240] Execute S1405, determine whether the torque indicated by the torque command is less than 0 and greater than the road adhesion torque, and determine whether the torque indicated by the torque command is greater than 0 and less than the road adhesion torque.

[0241] Among them, if the torque indicated by the torque command is negative and the road adhesion torque is negative, it is necessary to determine whether the torque indicated by the torque command is greater than the road adhesion torque; if the torque indicated by the torque command is positive and the road adhesion torque is positive, it is necessary to determine whether the torque indicated by the torque command is less than the road adhesion torque.

[0242] If not, execute S1406 to obtain the road adhesion torque as the torque indicated by the torque command.

[0243] If so, execute S1407 to determine whether the torque indicated by the torque command is less than 0 and less than the electric drive capacity of the drive motor.

[0244] If not, execute S1408 and output the torque command.

[0245] If so, execute S1409, obtain the electric drive capability as the torque indicated by the torque command, and generate a braking command based on the electric drive capability.

[0246] The braking force indicated by the braking command=the braking force corresponding to the torque indicated by the torque command-the electric drive capability, where the torque command is the torque command in S1407.

[0247] In this embodiment, the purpose of controlling the output torque of the drive motor at the first moment and the second moment is to automatically control the electric vehicle to travel at the speed indicated by the speed signal. When the road load of the road surface contacted by any wheel of the electric vehicle changes, the motor controller analyzes the speed signal and actively controls the drive motor to adjust the torque output so that the electric vehicle travels at the preset speed indicated by the speed signal, rather than responding to the electronic stability program parsing the speed signal into a torque signal and controlling the drive motor to adjust the torque output through the instruction of the torque signal issued by the vehicle controller, so as to achieve timely response to the change of road load and control the torque output of the drive motor to stabilize the vehicle speed at the preset speed, improve the speed fluctuation problem caused by the complex off-road terrain conditions, so that the electric vehicle can travel at the speed expected by the user during off-road cruising, improve the stability of the electric vehicle speed during off-road cruising, and improve the driving experience.

[0248] In one embodiment, the motor controller is also used to receive a torque instruction, and the motor controller is specifically used to: control the drive motor to output the torque indicated by the torque instruction at a first moment; and control the drive motor to output a torque less than or greater than the torque indicated by the torque instruction at a second moment.

[0249] For ease of understanding, the following Fig.15 The motor controller provided in the embodiment of the present application is described in detail.

[0250] Take four-wheel drive models as an example. Fig.15 1 shows a schematic diagram of a motor controller of an electric vehicle 100. Fig.15 In the process, the intelligent driving controller sends a speed signal to the vehicle controller, the vehicle controller converts the speed signal into a torque signal, and then sends a torque signal to motor controller 1, motor controller 2, motor controller 3 and motor controller 4. The four motor controllers send torque commands to the four drive motors and / or send braking commands to the braking system in response to the torque signals, and periodically adjust the torque indicated by the torque commands sent to the four drive motors and / or the braking force indicated by the braking commands sent to the braking system according to the rotary transformer signals fed back by the drive motors.

[0251] The specific process of adjusting the torque indicated by the torque command sent to the four drive motors and / or the braking force indicated by the braking command sent to the braking system by the four motor controllers is as described above. Fig.13 and Fig.14 As shown, no further description is given here.

[0252] In this embodiment, when the road load of the road surface contacted by any wheel of the electric vehicle changes, the motor controller actively controls the torque output of the drive motor to be greater than or less than the torque indicated by the torque signal. That is to say, when the road load changes, the motor controller can actively control the drive motor to adjust the torque output, rather than responding to the electronic stability program through the torque signal issued by the vehicle controller to control the drive motor to adjust the torque output. This achieves timely response to the change in road load and controls the torque output of the drive motor to stabilize the vehicle speed near the preset speed, improves the speed fluctuation problem caused by complex off-road terrain conditions, improves the speed stability of the electric vehicle during off-road cruising, and improves the driving experience.

[0253] In another embodiment of the present application, an electric vehicle is further provided, the electric vehicle comprising four drive motors and a motor controller; wherein:

[0254] At the first moment, the motor controller is used to control the four drive motors to output torque;

[0255] At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the motor controller is used to actively control the drive motor to adjust the torque output.

[0256] Among them, more detailed introductions on the implementation methods of the electric vehicle control method can be found in the above related descriptions.

[0257] It can be understood that all relevant contents of each step involved in the above method embodiment can be referred to the embodiment of the controller and the embodiment of the electric vehicle, and the embodiments of the present application will not be repeated here.

[0258] Finally, it should be noted that the above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A control method for an electric vehicle, characterized in that: The control method is used to control the driving system of the electric vehicle to improve the stability of the electric vehicle speed after the off-road cruise function of the electric vehicle is started, and the control method includes: At a first moment, the opening of the accelerator pedal of the electric vehicle is less than a preset accelerator pedal opening and the opening of the brake pedal is less than a preset brake pedal opening, and the drive motor of the electric vehicle is controlled to output torque so that the electric vehicle travels at a preset vehicle speed; At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the drive motor is actively controlled to adjust the torque output.

2. The control method according to claim 1, characterized in that: The control method specifically includes: At the second moment, the road load increases, and the drive motor is actively controlled to increase the torque output.

3. The control method according to claim 1, characterized in that: The control method specifically includes: At the second moment, the road load decreases, and the drive motor is actively controlled to reduce torque output.

4. The control method according to claim 1, characterized in that: The control method further comprises: At a third moment after the first moment, the preset vehicle speed decreases, the drive motor is controlled to output a reverse torque and / or the brake system of the electric vehicle is actively controlled to output a braking force; the torque direction of the reverse torque is opposite to the rotation direction of the wheels of the electric vehicle; At a fourth moment after the third moment, the road load of the road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the third moment, and the drive motor is actively controlled to adjust the reverse torque output and / or the braking system of the electric vehicle is actively controlled to adjust the braking force output.

5. The control method according to any one of claims 1 to 4, characterized in that: The control method specifically includes: After the first moment, any wheel of the electric vehicle slips, and the drive motor is actively controlled to reduce torque output; The slipping of any one of the wheels means that the slip rate or the slip ratio of any one of the wheels is greater than a preset value.

6. The control method according to claim 1, characterized in that: The control method further comprises: At the first moment, receiving a torque signal and controlling the drive motor to output a torque indicated by the torque signal; At the second moment, the torque output by the drive motor is actively controlled to be greater than or less than the torque indicated by the torque signal.

7. The control method according to claim 1, characterized in that: The control method further comprises: At the first moment, receiving a speed signal and controlling the drive motor to output torque so that the electric vehicle travels at the preset vehicle speed indicated by the speed signal; At the second moment, the speed signal is received and the drive motor is actively controlled to adjust the torque output so that the electric vehicle travels at the preset vehicle speed indicated by the speed signal.

8. The control method according to claim 2, characterized in that: The control method further comprises: At the second moment, actively controlling the increased torque output by the drive motor to be less than or equal to a preset torque; The smaller the adhesion coefficient of the road surface is, the smaller the preset torque is.

9. The control method according to claim 2, characterized in that: The control method specifically includes: At the second moment, the increase in the road load is a first increase, and the torque output by the drive motor is actively controlled to be a first torque; At the second moment, the increase in the road load is a second increase, and the torque output by the drive motor is actively controlled to be a second torque; The first increase is greater than the second increase, and the first torque is greater than the second torque.

10. The control method according to claim 2, characterized in that: The control method specifically includes: At the second moment, the greater the increase in the road load is, the greater the increase in the torque output by the drive motor is actively controlled.

11. The control method according to claim 1 or 4, characterized in that: The control method specifically includes: At the second moment and the fourth moment, the drive motor is actively controlled to adjust the torque output according to the motor torque signal and / or the resolver signal from the resolver sensor.

12. The control method according to claim 1, characterized in that: The control method further comprises: At the second moment, the motor speed indicated by the resolver signal from the resolver sensor decreases, and the drive motor is actively controlled to increase the torque output; At the second moment, the motor speed indicated by the resolver signal from the resolver sensor increases, and the drive motor is actively controlled to reduce the torque output.

13. The control method according to claim 1, characterized in that: The control method further comprises: At the second moment, the greater the rate of decrease of the motor speed indicated by the resolver signal from the resolver sensor, the greater the increase in the torque output by the drive motor is actively controlled; At the second moment, the greater the rising rate of the motor speed indicated by the resolver signal from the resolver sensor, the greater the reduction amount of the torque output by the drive motor is actively controlled.

14. A motor controller, characterized in that: The motor controller is used to control the output torque of the drive motor to make the electric vehicle travel at a preset speed after the off-road cruise function of the electric vehicle is started. The motor controller is specifically used to: At a first moment, the opening of the accelerator pedal of the electric vehicle is less than a preset accelerator pedal opening and the opening of the brake pedal is less than a preset brake pedal opening, and the drive motor is controlled to output torque so that the electric vehicle travels at the preset vehicle speed; At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the drive motor is actively controlled to adjust the torque output.

15. The motor controller according to claim 14, characterized in that: The motor controller is also used to receive a torque signal, and the motor controller is specifically used to: Controlling the drive motor to output the torque indicated by the torque signal at the first moment; At the second moment, the torque output by the driving motor is controlled to be smaller than or greater than the torque indicated by the torque signal.

16. The motor controller according to claim 14, characterized in that: The motor controller is also used to receive a speed signal, and the motor controller is specifically used to: At the first moment, controlling the drive motor to output torque so that the electric vehicle travels at the preset vehicle speed indicated by the speed signal; At the second moment, the drive motor is actively controlled to adjust the torque output so that the electric vehicle travels at the preset vehicle speed indicated by the speed signal.

17. An electric vehicle, characterized in that: The electric vehicle comprises four drive motors and a motor controller as claimed in any one of claims 14 to 16; wherein: At a first moment, the motor controller is used to control the output torque of the four drive motors; At a second moment after the first moment, a road load of a road surface contacted by any wheel of the electric vehicle changes relative to the road load of the road surface contacted by the wheel at the first moment, and the motor controller is used to actively control the drive motor to adjust the torque output.

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