Control system and control method for ramp auxiliary driving of electric vehicle

Abstract

The invention relates to the technical field of electric vehicle control, in particular to a control system and a control method for ramp auxiliary driving of an electric vehicle. The control system comprises a vehicle control unit VCU and a driving system; the vehicle control unit VCU is used for collecting vehicle CAN network signals including vehicle BMS system signals, MCU system signals, OBC system signals, accelerator pedal input signals, brake pedal input signals, gear input signals and hand brake input signals. The driving system comprises a motor controller MCU, a motor and a differential mechanism. The driving system executes different action responses in real time according to control instructions of a vehicle control unit VCU. The control instructions of the vehicle control unit VCU comprise a working mode, a request torque and an enable signal; according to the control method, by judging the acceleration of the vehicle, the situation that the vehicle mistakenly enters the anti-slip mode can be effectively reduced, the situation that the vehicle enters the anti-slip state is accelerated, the vehicle slip distance can be effectively reduced, and the comfort and safety of vehicle acceleration are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle control, and in particular to a control system and a control method for electric vehicle slope-assisted driving. Background Art

[0002] Existing electric vehicles use slope sensors combined with automatic parking systems to achieve hill assist functions, which have disadvantages such as high cost, long calibration cycle, expensive calibration development costs, and single function. They are increasingly deviating from the increasingly competitive market for new energy vehicles.

[0003] After searching, the Chinese patent with publication number CN111137137A discloses a control method, system and hybrid vehicle of a hybrid vehicle, the control method of which includes: when the vehicle controller detects that the power battery is unavailable, the bus voltage target value and the power generation torque limit value are sent to the motor controller; the motor controller detects the speed of the motor; when the difference between the speed and the motor idle value is equal to or less than the preset first difference threshold, the motor controller controls the power generation torque of the motor to be less than the power generation torque limit value. The control method, system and hybrid vehicle of the hybrid vehicle of the present invention, when it is detected that the power battery is unavailable and the speed of the motor is low, controls the power generation torque of the motor through the motor controller to avoid engine stalling caused by the power generation torque exceeding the current load capacity of the engine.

[0004] However, during use, the vehicle may easily enter the anti-slope mode by mistake by controlling whether the motor speed exceeds a threshold. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art and provide a control system and a control method for electric vehicle slope assisted driving, which can judge the absolute value of vehicle acceleration, effectively reduce the vehicle's mistaken entry into the anti-slope mode and accelerate the vehicle to enter the anti-slope state.

[0006] The technical solution of the present invention is:

[0007] A control system for slope-assisted driving of an electric vehicle without a slope sensor, comprising a vehicle controller VCU and a drive system;

[0008] The vehicle controller VCU is used to collect vehicle CAN network signals, including vehicle BMS system signals, MCU system signals, OBC system signals, accelerator pedal, brake pedal, gear position, and handbrake input signals;

[0009] The drive system includes the motor controller MCU, motor, and differential. The drive system performs different action responses in real time according to the control instructions of the vehicle controller VCU.

[0010] Preferably, the control instructions of the vehicle controller VCU include three types: working mode, requested torque and enable signal.

[0011] Preferably, the vehicle controller VCU performs system conversion through the internal signal acquisition module and then transmits it to the logic control module of the vehicle controller VCU. After completing the logic operation, the parameters are passed to the torque output module again. The torque output module comprehensively calculates the driving torque command required by the motor, and controls the drive system in parallel through the CAN bus command and the hard-wired signal of the signal output module.

[0012] Preferably, the torque and speed data are filtered.

[0013] Preferably, the speed fluctuation is less than 20 Rpm in static state and less than 50 Rpm in dynamic state.

[0014] A control method for a control system of an electric vehicle slope assisted driving without a slope sensor, the control method steps are as follows:

[0015] S11: The vehicle controller VCU determines whether the vehicle meets the Ready condition and the drivable state according to the vehicle status;

[0016] S12: The vehicle controller VCU determines whether the vehicle is stationary;

[0017] S13: The vehicle controller VCU determines the stationary state of the vehicle through the ABS speed signal or the motor speed:

[0018] S14: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid forward gear;

[0019] S15: The vehicle controller VCU determines whether the motor speed is less than -50RPM or the vehicle acceleration is less than the set value, and maintains it for 100ms, then the vehicle enters the hill assist mode;

[0020] S16: The vehicle controller VCU sends the vehicle driving torque as zero;

[0021] S17: by calculating the difference between the target vehicle speed and the actual vehicle speed in real time, the driving torque of the vehicle is adjusted through PID adaptive control, so that the vehicle automatically drives on the slope at the set speed;

[0022] S18: judging whether the driver has driving intention according to the state of the accelerator pedal;

[0023] S19: Calculate the vehicle driving torque by the depth of the accelerator pedal being depressed, and exit the hill assist mode when the required torque is greater than the current actual vehicle driving torque, and continue to execute the hill assist mode when the required torque is less than the current actual vehicle driving torque;

[0024] S20: The vehicle controller sends the torque required by the vehicle to the MCU motor controller to drive the vehicle normally and exit the hill assist mode;

[0025] S21: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid reverse gear;

[0026] S22: The vehicle controller VCU determines whether the motor speed is greater than 50RPM or the vehicle acceleration is greater than the set value, and maintains the value for 100ms before the vehicle enters the hill assist mode;

[0027] S23: The vehicle controller VCU determines whether the actual speed of the vehicle is greater than the set value, and this state includes forward gear and reverse gear;

[0028] S24: When the actual vehicle speed is greater than the set value, the vehicle enters the creep mode and exits the hill assist mode.

[0029] Preferably, in step S17, if the condition of S15 is met, a positive torque is sent to drive the vehicle forward, and if the condition of S22 is met, a negative torque is sent to drive the vehicle backward.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] By optimizing the vehicle controller software, collecting CAN bus data and driving signal hard-line data in real time, and judging the vehicle's driving trend and the driver's driving intention through algorithms, it is possible to achieve that when the vehicle stops on a slope, the brake pedal can be released without stepping on the accelerator pedal, and the slope assist driving function can be automatically exited after the brake pedal is pressed to stop the vehicle, and it can be automatically entered again after the brake pedal is released.

[0032] The vehicle's tendency to roll down a slope is determined by judging the absolute value of the vehicle's acceleration rather than simply judging that the motor speed exceeds a certain threshold to enter the anti-rolling slope mode. By judging the vehicle's acceleration, the vehicle's accidental entry into the anti-rolling slope mode can be effectively reduced and the vehicle's entry into the anti-rolling slope state can be accelerated, which can effectively reduce the vehicle's rolling slope distance and provide comfort and safety for vehicle acceleration.

[0033] After the vehicle enters the anti-slope mode, when the vehicle climbs a slope, the vehicle can move forward slowly without stepping on the accelerator pedal. The vehicle automatically exits by stepping on the brake pedal. The VCU judges the vehicle's driving status, giving the vehicle flat-ground creeping function and slope assist driving function, rather than the traditional slope assist holding function.

[0034] This method can realize the function of vehicle slope assist without increasing hardware costs, thereby improving vehicle driving comfort, reducing vehicle development costs, and shortening vehicle development cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 It is a structural schematic diagram of the control system of the present invention.

[0037] Figure 2 It is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a control system for electric vehicle hill-climbing assisted driving, which integrates a vehicle controller VCU and a drive system;

[0041] The vehicle controller VCU is used to collect vehicle CAN network signals, including vehicle BMS system signals, MCU system signals, OBC system signals, accelerator pedal, brake pedal, gear position, and handbrake input signals;

[0042] The drive system includes the motor controller MCU, motor, and differential. The drive system performs different action responses in real time according to the control instructions of the vehicle controller VCU.

[0043] Preferably, the control instructions of the vehicle controller VCU include three types: working mode, requested torque and enable signal.

[0044] Preferably, the vehicle controller VCU performs system conversion through the internal signal acquisition module and then transmits it to the logic control module of the vehicle controller VCU. After completing the logic operation, the parameters are passed to the torque output module again. The torque output module comprehensively calculates the driving torque command required by the motor, and controls the drive system in parallel through the CAN bus command and the hard-wired signal of the signal output module.

[0045] Preferably, the torque and speed data are filtered to effectively reduce noise interference.

[0046] Preferably, in a static state, the speed fluctuation is strictly controlled within 20RPM; and in a dynamic state, the speed fluctuation is also required not to exceed 50RPM, which provides a strong guarantee for the smooth driving of the vehicle.

[0047] Example 2

[0048] On the basis of Example 1, Figure 2 As shown, a control method of a control system for electric vehicle hill assisted driving, the control method steps are as follows:

[0049] S11: The vehicle controller VCU determines whether the vehicle meets the Ready condition and the drivable state according to the vehicle status;

[0050] S12: The vehicle controller VCU determines whether the vehicle is stationary;

[0051] S13: The vehicle controller VCU determines the stationary state of the vehicle through the ABS speed signal or the motor speed:

[0052] S14: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid forward gear;

[0053] S15: The vehicle controller VCU determines whether the motor speed is less than -50RPM or the vehicle acceleration is less than the set value, and maintains it for 100ms, then the vehicle enters the hill assist mode;

[0054] S16: The vehicle controller VCU sends the vehicle driving torque as zero;

[0055] S17: by calculating the difference between the target vehicle speed and the actual vehicle speed in real time, the driving torque of the vehicle is adjusted through PID adaptive control, so that the vehicle automatically drives on the slope at the set speed;

[0056] S18: judging whether the driver has driving intention according to the state of the accelerator pedal;

[0057] S19: Calculate the vehicle driving torque by the depth of the accelerator pedal being depressed, and exit the hill assist mode when the required torque is greater than the current actual vehicle driving torque, and continue to execute the hill assist mode when the required torque is less than the current actual vehicle driving torque;

[0058] S20: The vehicle controller sends the torque required by the vehicle to the MCU motor controller to drive the vehicle normally and exit the hill assist mode;

[0059] S21: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid reverse gear;

[0060] S22: The vehicle controller VCU determines whether the motor speed is greater than 50RPM or the vehicle acceleration is greater than the set value, and maintains the value for 100ms before the vehicle enters the hill assist mode;

[0061] S23: The vehicle controller VCU determines whether the actual speed of the vehicle is greater than the set value, and this state includes forward gear and reverse gear;

[0062] S24: When the actual vehicle speed is greater than the set value, the vehicle enters the creep mode and exits the hill assist mode.

[0063] Preferably, in step S17, if the condition of S15 is met, a positive torque is sent to drive the vehicle forward, and if the condition of S22 is met, a negative torque is sent to drive the vehicle backward.

[0064] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of these shall be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A control system for electric vehicle slope assisted driving, characterized in that: Including vehicle controller VCU and drive system; The vehicle controller VCU is used to collect vehicle CAN network signals, including vehicle BMS system signals, MCU system signals, OBC system signals, accelerator pedal, brake pedal, gear position, and handbrake input signals; The drive system includes the motor controller MCU, motor, and differential. The drive system performs different action responses in real time according to the control instructions of the vehicle controller VCU.

2. The control system for electric vehicle hill-climbing assisted driving as claimed in claim 1, characterized in that: The control instructions of the vehicle controller VCU include three types: working mode, requested torque, and enable signal.

3. The control system for electric vehicle hill-climbing assisted driving as claimed in claim 1, characterized in that: The vehicle controller VCU performs system conversion through the internal signal acquisition module and uniformly transmits it to the logic control module of the vehicle controller VCU. After completing the logic operation, the parameters are passed to the torque output module again. The torque output module comprehensively calculates the driving torque command required by the motor, and controls the drive system in parallel through the CAN bus command and the hard-wired signal of the signal output module.

4. The control system for electric vehicle hill-climbing assisted driving as claimed in claim 3, characterized in that: The torque and speed data are filtered.

5. The control system for electric vehicle hill-climbing assisted driving as claimed in claim 4, characterized in that: The speed fluctuation is required to be <20Rpm when static and <50Rpm when dynamic.

6. A control method for a control system of an electric vehicle hill-climbing assisted driving system, using the control system of an electric vehicle hill-climbing assisted driving system as claimed in any one of claims 1 to 5, characterized in that: The control method steps are as follows: S11: The vehicle controller VCU determines whether the vehicle meets the Ready condition and the drivable state according to the vehicle status; S12: The vehicle controller VCU determines whether the vehicle is stationary; S13: The vehicle controller VCU determines the stationary state of the vehicle through the ABS speed signal or the motor speed: S14: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid forward gear; S15: The vehicle controller VCU determines whether the motor speed is less than -50RPM or the vehicle acceleration is less than the set value, and maintains it for 100ms, then the vehicle enters the hill assist mode; S16: The vehicle controller VCU sends the vehicle driving torque as zero; S17: by calculating the difference between the target vehicle speed and the actual vehicle speed in real time, the driving torque of the vehicle is adjusted through PID adaptive control, so that the vehicle automatically drives on the slope at the set speed; S18: judging whether the driver has driving intention according to the state of the accelerator pedal; S19: Calculate the vehicle driving torque by the depth of the accelerator pedal being depressed, and exit the hill assist mode when the required torque is greater than the current actual vehicle driving torque, and continue to execute the hill assist mode when the required torque is less than the current actual vehicle driving torque; S20: The vehicle controller sends the torque required by the vehicle to the MCU motor controller to drive the vehicle normally and exit the hill assist mode; S21: The vehicle controller VCU collects the gear position signal and the vehicle status through hard wire to determine whether the vehicle is in a valid reverse gear; S22: The vehicle controller VCU determines whether the motor speed is greater than 50RPM or the vehicle acceleration is greater than the set value, and maintains the value for 100ms before the vehicle enters the hill assist mode; S23: The vehicle controller VCU determines whether the actual speed of the vehicle is greater than the set value, and this state includes forward gear and reverse gear; S24: When the actual vehicle speed is greater than the set value, the vehicle enters the creep mode and exits the hill assist mode.

7. The control method of a control system for an electric vehicle hill-climbing assisted driving system as claimed in claim 6, characterized in that: In the step S17, if the condition of S15 is met, a positive torque is sent to drive the vehicle forward, and if the condition of S22 is met, a negative torque is sent to drive the vehicle backward.

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