Off-road cruise control method based on double-motor PI control

Abstract

The application provides an off-road cruise control method based on double-motor PI control, which comprises the following steps: step S1, when a vehicle enters an off-road cruise mode, a vehicle controller identifies a current target gear; step S2, the vehicle controller calculates a target vehicle speed according to the target gear; step S3, the vehicle controller calculates a difference between the target vehicle speed and an actual vehicle speed, and calculates an initial target torque by using a PI control algorithm according to the difference; and step S4, the vehicle controller determines whether to distribute the initial target torque to front and rear motors of the vehicle according to a vehicle state. The application can control the vehicle speed in real time when the vehicle is in off-road cruise, so that the vehicle speed is relatively stable.

Description

Technical Field

[0001] This invention belongs to the field of automotive control technology, specifically relating to an off-road cruise control method based on dual-motor PI control. Background Technology

[0002] When modern cars are in off-road mode, they need to deal with complex road conditions such as mountains, mud, rocks, and sand. Therefore, driving in off-road conditions requires a certain level of skill, especially for novice drivers. The complex terrain in off-road mode presents significant challenges, easily leading to unstable speeds that fluctuate. Therefore, designing an off-road cruise control method based on dual-motor PI control to achieve stable vehicle speed control in off-road cruise mode has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0003] The purpose of this invention is to provide an off-road cruise control method based on dual-motor PI control to solve the above-mentioned technical problems in the prior art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] An off-road cruise control method based on dual-motor PI control includes the following steps:

[0006] Step S1: When the vehicle controller detects that the vehicle has entered off-road cruise mode, it identifies the current target gear.

[0007] Step S2: The vehicle controller calculates the target vehicle speed based on the target gear.

[0008] Step S3: The vehicle controller calculates the difference between the target vehicle speed and the actual vehicle speed, and uses the PI control algorithm to calculate the initial target torque based on this difference;

[0009] Step S4: The vehicle controller determines whether to distribute the initial target torque to the front and rear motors of the vehicle based on the overall vehicle status.

[0010] The vehicle status includes whether the vehicle is in D gear, whether it is parked, whether the driver is pressing the brake, and whether the driver is pressing the accelerator.

[0011] If the vehicle is in D gear and not in parking mode, and the driver is not pressing the brake or the accelerator, the initial target torque will be distributed to the front motor and the rear motor according to a certain ratio.

[0012] If the vehicle is not in Drive (D) or parked, or if the driver applies the brakes, the initial target torque will not be distributed to the front and rear motors.

[0013] Preferably, step S4 further includes: if the vehicle controller receives a signal from the driver pressing the accelerator, it calculates the accelerator torque based on the accelerator position, compares the accelerator torque with the initial target torque, and decides whether the driver should take over based on the comparison result.

[0014] Preferably, if the throttle torque is greater than the initial target torque, the throttle torque is output and the vehicle is taken over by the driver. After the driver releases the throttle, the vehicle controller looks up the corresponding target negative torque according to the current actual vehicle speed and distributes the target negative torque to the rear motor to reduce the vehicle speed to near the target speed. Then, the PI control algorithm is used to calculate the current initial target torque and distribute it to the front motor and the rear motor.

[0015] Preferably, if the throttle torque is not greater than the initial target torque, the throttle torque is not responded to, the vehicle does not require driver intervention, and the initial target torque is distributed to the front motor and the rear motor.

[0016] Preferably, when distributing the initial target torque to the front and rear motors of the vehicle, if the vehicle controller receives the vehicle's steering signal, it looks up the corresponding steering compensation torque in a table based on the current steering angle, and then superimposes the steering compensation torque with the initial target torque before outputting it.

[0017] Preferably, when distributing the initial target torque to the front and rear motors of the vehicle, if the vehicle controller receives a slope signal, it looks up the corresponding slope compensation torque according to the current slope, adds the slope compensation torque to the initial target torque, and then outputs it.

[0018] Preferably, when distributing the initial target torque to the front and rear motors of the vehicle, if the vehicle controller simultaneously receives the vehicle's steering signal and slope signal, the steering compensation torque and slope compensation torque are superimposed on the initial target torque before being output.

[0019] Preferably, the ratio is 1:1.

[0020] The beneficial effects of this invention are as follows:

[0021] The off-road cruise control method based on dual-motor PI control of the present invention can control the vehicle speed in real time during off-road cruise, making the vehicle speed more stable and avoiding the situation where the vehicle speed fluctuates when driving on complex road surfaces. This ensures stable driving of the vehicle and also reduces the requirements for the driver's driving skills. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly described below, and the specific embodiments of the present invention will be further described in detail with reference to the drawings, wherein...

[0023] Figure 1 A flowchart of an off-road cruise control method based on dual-motor PI control provided in an embodiment of the present invention. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0025] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0026] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0027] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0028] like Figure 1 As shown, this embodiment of the invention provides an off-road cruise control method based on dual-motor PI control, which includes the following steps:

[0029] Step S1: When the vehicle controller detects that the vehicle has entered off-road cruise mode, it identifies the current target gear.

[0030] Step S2: The vehicle controller calculates the target vehicle speed based on the target gear.

[0031] Step S3: The vehicle controller calculates the difference between the target vehicle speed and the actual vehicle speed, and uses the PI control algorithm to calculate the initial target torque based on this difference;

[0032] Step S4: The vehicle controller determines whether to distribute the initial target torque to the front and rear motors of the vehicle based on the overall vehicle status.

[0033] The vehicle status includes whether the vehicle is in D gear, whether it is parked, whether the driver is pressing the brake, and whether the driver is pressing the accelerator.

[0034] If the vehicle is in D gear and not in parking mode, and the driver is not pressing the brake or the accelerator, the initial target torque will be distributed to the front motor and the rear motor according to a certain ratio.

[0035] If the vehicle is not in D gear or is parked, or if the driver has applied the brakes, the initial target torque will not be distributed to the front and rear motors. In this case, the initial target torque can also be set to zero.

[0036] The off-road cruise control method based on dual-motor PI control provided in this invention can control the vehicle speed in real time during off-road cruise, making the vehicle speed more stable and avoiding the situation where the vehicle speed fluctuates when driving on complex road surfaces, thus ensuring stable driving of the vehicle; at the same time, it also reduces the requirements for the driver's driving skills.

[0037] Furthermore, step S4 also includes: if the vehicle controller receives a signal from the driver pressing the accelerator, it calculates the throttle torque based on the throttle position, compares the throttle torque with the initial target torque, and determines whether the driver should take over based on the comparison result, specifically:

[0038] If the throttle torque is greater than the initial target torque, the throttle torque is output and the vehicle is taken over by the driver. After the driver releases the throttle, the vehicle controller looks up the corresponding target negative torque according to the current actual vehicle speed and distributes the target negative torque to the rear motor to reduce the actual vehicle speed to near the target speed, such as within 3 km / h. Then, the PI control algorithm is used to calculate the current initial target torque and distribute it to the front motor and the rear motor.

[0039] If the throttle torque is not greater than the initial target torque, the throttle torque will not be responded to, the vehicle will not require driver intervention, and the initial target torque will be distributed to the front and rear motors.

[0040] Specifically, if the difference between the target vehicle speed and the actual vehicle speed is denoted as Δ, then Δ = target vehicle speed minus actual vehicle speed, and the value of Δ can be positive or negative. The specific method for calculating the initial target torque using the PI control algorithm based on this difference is as follows: The torque value under P parameter control at the current moment is obtained by multiplying the value of Δ by the value of the linear proportional parameter P; and the torque value under I parameter control at the current moment is obtained by multiplying the value of Δ by the value of the differential parameter I. This torque value needs to be superimposed over the sampling period to eliminate the steady-state error existing under P parameter control; then, the torque value calculated under P parameter control and the torque value calculated under I parameter control are superimposed to obtain the initial target torque.

[0041] Furthermore, in step S4, in the case where the initial target torque is distributed to the front and rear motors of the vehicle:

[0042] If the vehicle controller receives the vehicle's steering signal, it looks up the corresponding steering compensation torque in a table based on the current steering angle, adds the steering compensation torque to the initial target torque, and then outputs it. At this time, the added torque can be distributed to the front motor and the rear motor according to a certain ratio.

[0043] If the vehicle controller receives a slope signal, it will look up the corresponding slope compensation torque according to the current slope, add the slope compensation torque to the initial target torque and then output it. At this time, the added torque can be distributed to the front motor and the rear motor according to a certain ratio.

[0044] If the vehicle controller receives both the vehicle's steering signal and the slope signal simultaneously, it will superimpose the steering compensation torque and the slope compensation torque with the initial target torque before outputting them. At this time, the superimposed torque can be distributed to the front motor and the rear motor according to a certain ratio.

[0045] Understandably, the relevant data obtained through the table lookup method can be obtained in advance through experiments, and then the corresponding tables can be created. For example, the vehicle speed-target negative torque correspondence table can be obtained in advance through experiments, and the target negative torque is positively correlated with the vehicle speed; the steering angle-steering compensation torque correspondence table can be obtained in advance through experiments, and the steering compensation torque is positively correlated with the steering angle; the gradient-gradient compensation torque correspondence table can be obtained in advance through experiments, and the gradient compensation torque is positively correlated with the gradient. When the vehicle is climbing a slope, the gradient is positive, and the corresponding gradient compensation torque is also positive; while when the vehicle is descending a slope, the gradient is negative, and the corresponding gradient compensation torque is also negative.

[0046] Specifically, the aforementioned ratio is 1:1. It is understandable that in practical applications, the specific value of this ratio can be flexibly set according to needs.

[0047] In this invention, after the driver selects the off-road cruise function and the target gear through the vehicle's control panel, the vehicle control unit (VCU) calculates the target vehicle speed based on the target gear. Then, it performs a PI calculation based on the difference between the target speed and the actual vehicle speed to obtain the current initial target torque. This initial target torque is then distributed to the front and rear motors in a certain proportion to drive the vehicle. Furthermore, it can make real-time corrections to the initial target torque based on the real-time difference between the target speed and the actual vehicle speed to ensure relatively stable vehicle speed. When a steering signal and a slope signal are received, steering compensation torque and slope compensation torque are added to the current initial target torque calculated by the PI calculation before being distributed to the front and rear motors.

[0048] Specifically, the VCU can obtain the vehicle's steering signal and steering angle information through the vehicle's airbag controller (SRS), and obtain the slope signal and the slope of the road surface through the vehicle's inertial measurement unit (IMU).

[0049] When the vehicle is climbing a slope, the overall resistance of the vehicle suddenly increases. At this time, the control method of this invention can provide a large slope torque compensation to the front motor and the rear motor to prevent the vehicle speed from dropping too low or even rolling back down the slope. When the vehicle is going downhill, the resistance suddenly decreases. At this time, this invention can provide negative torque to the two motors for dragging to prevent the vehicle speed from being too high. When turning, the overall resistance of the vehicle increases. At this time, this invention can provide a corresponding amount of torque compensation to the two motors according to the size of the turning angle to prevent the vehicle speed from dropping.

[0050] This invention allows the driver to take over control of the vehicle when the actual speed exceeds the target speed after the throttle torque kicks in. Once the driver releases the throttle, the rear motor applies a negative torque to reduce the vehicle speed. During this process, excess kinetic energy can be converted into electrical energy, increasing the vehicle's range. This invention is particularly effective in controlling the speed of hybrid four-wheel-drive pickup trucks during off-road cruising, ensuring stable vehicle speed and preventing excessive or insufficient speed on complex road conditions. This invention enables the vehicle to maintain a stable speed on complex terrain in off-road cruising mode, providing gradient torque compensation during uphill and downhill sections, and steering torque compensation during turns, thus maintaining a stable speed.

[0051] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A method for off-road cruise control based on dual-motor PI control, characterized in that, It comprises the following steps: Step S1, when the vehicle enters the off-road cruise mode, the vehicle controller identifies the current target gear; Step S2, the vehicle controller calculates the target speed according to the target gear; Step S3, the vehicle controller calculates the difference between the target speed and the actual speed, and calculates the initial target torque using the PI control algorithm according to the difference; Step S4, the vehicle controller determines whether to distribute the initial target torque to the front motor and the rear motor of the vehicle according to the vehicle state; The vehicle state includes whether the vehicle is in D, whether it is in the parking state, whether the driver steps on the brake, and whether the driver steps on the accelerator; If the vehicle is in D, not in the parking state, the driver does not step on the brake and does not step on the accelerator, then the initial target torque is distributed to the front motor and the rear motor according to a certain ratio; If the vehicle is not in D or is in the parking state or the driver steps on the brake, the initial target torque is not distributed to the front motor and the rear motor; Step S4 also includes: if the vehicle controller receives a signal that the driver steps on the accelerator, the accelerator torque is calculated according to the accelerator size, and the accelerator torque is compared with the initial target torque to determine whether to take over by the driver according to the comparison result; If the accelerator torque is greater than the initial target torque, the accelerator torque is output, the vehicle is taken over by the driver, and after the driver releases the accelerator, the vehicle controller obtains the corresponding target negative torque according to the current actual speed, and distributes the target negative torque to the rear motor to reduce the vehicle speed to the vicinity of the target speed, and then calculates the current initial target torque using the PI control algorithm, and then distributes it to the front motor and the rear motor.

2. The off-road cruise control method based on dual-motor PI control according to claim 1, characterized in that, If the accelerator torque is not greater than the initial target torque, the accelerator torque is not responded, the vehicle does not need to be taken over by the driver, and the initial target torque is distributed to the front motor and the rear motor.

3. The dual-motor PI control based off-road cruise control method of claim 1, wherein, When the initial target torque is distributed to the front motor and the rear motor of the vehicle, if the vehicle controller receives a steering signal of the vehicle, the corresponding steering compensation torque is obtained according to the current steering angle, and the steering compensation torque is superimposed on the initial target torque before output.

4. The dual-motor PI control based off-road cruise control method according to claim 3, wherein, When the initial target torque is distributed to the front motor and the rear motor of the vehicle, if the vehicle controller receives a slope signal, the corresponding slope compensation torque is obtained according to the current slope, and the slope compensation torque is superimposed on the initial target torque before output.

5. The dual-motor PI control based off-road cruise control method according to claim 4, wherein, When the initial target torque is distributed to the front motor and the rear motor of the vehicle, if the vehicle controller receives a steering signal and a slope signal of the vehicle at the same time, the steering compensation torque and the slope compensation torque are superimposed on the initial target torque before output.

6. The dual-motor PI control based off-road cruise control method according to any one of claims 1 to 5, characterized in that, The above certain ratio is 1:1.

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