Intelligent driving negative torque longitudinal control method and automobile

Abstract

The invention discloses an intelligent driving negative torque longitudinal control method which comprises the following steps: after an intelligent driving function of a vehicle is started, if it is detected that the vehicle has a deceleration demand, acquiring an energy recovery capacity value sent by a VCU in real time through an intelligent driving controller, and setting a corresponding maximum supportable threshold value T1 of negative torque; calculating a target negative torque value T2 corresponding to the deceleration demand; setting a switchover interval torque value T capable of being calibrated; and according to the values of T1, T2 and T, a negative torque request is sent to the VCU through the intelligent driving controller or deceleration is directly requested to the ESP through the intelligent driving controller so as to meet the deceleration requirement. The method has the advantages that speed reduction control is achieved by controlling the negative torque in the intelligent driving process, the conditions of pause, unstable vehicle speed and the like in the speed reduction control process are reduced, and the driving experience is improved.

Description

Technical Field

[0001] The present invention relates to the field of automobile automatic driving control, and in particular to a method for intelligent driving negative torque longitudinal control. Background Art

[0002] On current passenger cars with hybrid / pure electric vehicles with intelligent driving functions, when the vehicle longitudinal control VLC (Vehicle Longitudinal Control) function performs deceleration control, the intelligent driving controller mainly uses the ESP hydraulic brake control to decelerate and brake. When the intelligent driving deceleration request value is small, ESP can request energy recovery from the VCU for braking.

[0003] Because ESP simultaneously performs hydraulic braking and requests energy recovery braking from the VCU, when the intelligent driving controller requires a small deceleration, the switching of hydraulics and energy recovery, and the difference in the deceleration reference benchmarks between the intelligent driving controller and ESP control, can easily cause the vehicle to jerk during small deceleration control, or the vehicle speed to jump when going up or down slopes.

[0004] Especially in the field of intelligent driving or autonomous driving, such as the ACC adaptive cruise control function, during the ACC adaptive cruise control process, there are many scenarios where small deceleration braking is requested. According to the existing technology, whether it is hydraulic braking, or hydraulic and energy recovery superimposed braking, it is easy to cause the vehicle to stall or unstable speed control when going uphill or downhill, resulting in a poor ACC experience, affecting the vehicle's user experience and vehicle stability. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for intelligent driving negative torque longitudinal control, which realizes deceleration control by controlling the negative torque during the intelligent driving process, reduces the frustration and unstable vehicle speed during the deceleration control process, and improves the driving experience.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a method for intelligent driving negative torque longitudinal control, comprising:

[0007] After the vehicle intelligent driving function is turned on, if it is detected that the vehicle has a deceleration requirement, the intelligent driving controller obtains the energy recovery capability value sent by the VCU in real time and sets the corresponding maximum supported threshold value T1 of the negative torque;

[0008] Calculate the target negative torque value T2 corresponding to the deceleration requirement;

[0009] Set the calibrable switching interval torque value △T;

[0010] According to the values ​​of T1, T2 and △T, the intelligent driving controller sends a negative torque request to the VCU or directly requests deceleration to the ESP through the intelligent driving controller to meet the deceleration demand.

[0011] The calibratable switching interval torque value △T is set to meet the requirement: 0<|T2|+△T<|T1|.

[0012] When |T2|>|T1|, the intelligent driving controller directly requests deceleration from ESP. Otherwise, the relationship between |T2|-△T and |T1| is judged. When |T2|-△T<|T1|, the intelligent driving controller directly sends a negative torque request to VCU.

[0013] When |T2|-△T<|T1|, the relationship between |T2|+△T and |T1| is judged in real time. When |T2|+△T≥|T1|, the intelligent driving controller exits and directly sends a negative torque request to the VCU, and the intelligent driving control directly requests deceleration from the ESP.

[0014] When |T2|-△T<|T1|, the relationship between |T2|+△T and |T1| is judged in real time. When |T2|+△T<|T1|, it is judged whether the intelligent driving function is exited. If so, the deceleration demand ends. If not, the maximum supportable threshold value T1 and target negative torque value T2 of negative torque are continuously monitored and updated, and negative torque requests are continuously issued to VCU through the intelligent driving controller based on T1, T2 and △T values, or deceleration is directly requested to ESP through the intelligent driving controller to meet the deceleration demand.

[0015] The calculation of the target negative torque value T2 includes: calculating the target deceleration value a1; and converting the target deceleration value into the target negative torque value T2 through a deceleration and torque model.

[0016] The calculation of the target negative torque value T2 also includes real-time acquisition of the current vehicle speed, accelerometer signal, and slope signal, and calculation of the target deceleration value a1 based on the current vehicle speed, accelerometer signal, and slope signal.

[0017] The intelligent driving controller directly sends a negative torque request to the VCU and simultaneously corrects the negative torque request value in real time through the PI control model to achieve the purpose of vehicle deceleration.

[0018] A car, which adopts the intelligent driving negative torque longitudinal control method to perform negative torque longitudinal control on the car.

[0019] The advantages of the present invention are: deceleration control is achieved by controlling the negative torque during intelligent driving, reducing setbacks, unstable vehicle speed and other situations during deceleration control, and improving driving experience. The intelligent driving negative torque longitudinal control method of this solution does not require hardware modification. It is developed through the intelligent driving controller software model. When a small deceleration is requested, negative torque is directly requested from the VCU for braking. Because the negative torque is achieved through the motor, the control is linear. Compared with previous hydraulic braking, it is more linear and smooth. Improves the comfort of the intelligent driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0021] Figure 1 This is a flow chart of the method for negative torque longitudinal control of the present invention. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0023] This solution is mainly aimed at the defects of low control accuracy and easy setbacks in the longitudinal speed control in automatic driving or intelligent driving, involving a new negative torque control method. Intelligent driving or automatic driving involves many functions, such as ADAS, ACC and other functions. This solution is designed and implemented for the ACC function. The specific introduction is as follows:

[0024] The technical problem to be solved by this solution is that when the intelligent driving controller performs small deceleration control, according to the mainstream solution of existing technology, hydraulic pressure or energy recovery distribution is performed through ESP, which can easily cause the vehicle to stall or unstable speed control when going uphill or downhill, and poor ACC experience.

[0025] The solution of this application to the above problems is:

[0026] After the vehicle ACC function is turned on, when the vehicle needs to slow down, the intelligent driving controller receives the energy recovery capability value sent by the VCU in real time (the VCU calculates the maximum energy recovery capability value and sends it to the vehicle body bus through the power battery pack SOC value, the maximum charge and discharge of the motor, and other factors, and the intelligent driving controller only obtains this value from the bus), and sets the maximum supportable threshold value T1 of negative torque (threshold T1 is the energy recovery capability value sent by the VCU on the vehicle body bus, usually in N·m). The vehicle's required deceleration situation is determined by the ACC function through detecting the cruising distance and distance threshold with the vehicle in front and making a comprehensive judgment to obtain a deceleration requirement, and then tries to obtain the energy recovery capability value. The intelligent driving controller calculates the target negative torque value T2 based on the target calculation module. Combined with the current vehicle speed, accelerometer, slope and other signals, the target deceleration a1 is calculated (obtained according to the vehicle dynamics model, that is, the vehicle is regarded as a rigid point and a force analysis is performed to obtain the result); through the deceleration and torque model (when the mass of the whole vehicle is known, the second derivative of the deceleration is known, the required reaction force can be obtained, and then multiplied by the tire radius, that is, the transmission ratio of the whole vehicle, the required target negative torque T2 can be obtained), the target deceleration value is converted into the target negative torque value T2.

[0027] In order to ensure that the intelligent driving controller directly makes negative torque braking requests and switches smoothly with ESP hydraulic braking, a calibrable switching interval torque △T value is set, where 0<|T2|+△T<|T1| is required. △T is introduced to control this variable through PI. PI control is a mature control technology, namely proportional integral control. Because the T2 value calculated above is biased, it may cause vehicle speed fluctuations. After the introduction of △T, this fluctuation can be reduced by controlling this △T value. △T is a calibrable value and will be specifically calibrated during actual vehicle calibration.

[0028] When |T2|-△T<|T1|, the intelligent driving controller directly sends a negative torque request to the VCU, and at the same time, the negative torque request value is corrected in real time through the PI control model to achieve the purpose of vehicle deceleration, and then real-time monitoring is performed to see whether |T2|+△T≥|T1| is reached. If so, the intelligent driving controller exits and directly sends a negative torque request to the VCU, and the intelligent driving control directly requests deceleration from the ESP; the PI model is proportional integral, and this model is used to calibrate the P and I values ​​in the control technology so that the system reaches a stable state; after sending a negative torque request to the VCU, the VCU will immediately perform energy recovery, and energy recovery will accelerate the vehicle; after requesting deceleration from ESP, the subsequent execution strategy or logic of ESP is that ESP will perform hydraulic braking, and by controlling the wheel cylinder pressure, the deceleration of the whole vehicle is executed according to the deceleration assigned by the intelligent driving controller; the intelligent driving solution of the prior art mainly performs deceleration through hydraulic pressure, and the hydraulic linearity is low, which will cause the whole vehicle to stall during the execution process. This solution is mainly executed through energy recovery, and energy recovery is achieved by motor reversal to achieve deceleration, with high linearity, and almost no stalling of the whole vehicle.

[0029] When |T2|>|T1|, it means that the VCU negative torque control capability is insufficient. At this time, the intelligent driving controller directly requests deceleration from ESP for hydraulic braking. Negative torque control through the intelligent driving controller can reduce the impact of vehicle setbacks when executing the ACC function or unstable speed control when going uphill or downhill. When the intelligent driving ACC function controls deceleration, the deceleration requirements in most scenarios are not large and will not exceed the VCU energy recovery capability value. This patent intends to use this solution to achieve energy recovery in most ACC control deceleration scenarios, but in order to ensure safety and redundancy, if a scenario requires emergency deceleration, it will be executed by hydraulics, and the hydraulics can provide a greater deceleration.

[0030] like Figure 1 As shown, the method of intelligent driving negative torque longitudinal control described in the present invention.

[0031] 1. When the ACC function is turned on, the maximum supportable threshold value T1 of negative torque is set according to the energy recovery capability value sent by VCU in real time;

[0032] 2. The intelligent driving controller calculates the current required speed target value according to the target calculation module, and calculates the target deceleration a1 in combination with the current vehicle speed, accelerometer, slope and other signals; the target calculation module refers to the intelligent driving controller based on sensors such as cameras and millimeter-wave radars, such as the distance, speed, relative speed and other signals from the vehicle in front, and then calculates the speed that the vehicle should maintain at this time according to the following distance parameters set by the user.

[0033] 3. Through the deceleration and torque model, the target deceleration value is converted into the target negative torque value T2.

[0034] 4. Set the switching interval torque △T value (0<|T2|+△T<|T1|);

[0035] 5. When |T2|-△T<|T1|, the intelligent driving controller directly sends a negative torque request to the VCU, and the negative torque request value is corrected in real time through the PI control model. When |T2|+△T≥|T1|, the intelligent driving controller exits and directly sends a negative torque request to the VCU, and the intelligent driving controller directly requests deceleration from the ESP.

[0036] 6. When |T2|>|T1|, it means that the VCU negative torque control capability is insufficient. At this time, the intelligent driving controller directly requests deceleration from ESP for hydraulic braking.

[0037] The working principle of the intelligent driving negative torque longitudinal control method of the present application is: when the intelligent driving controller is performing small deceleration control, and the negative torque response capability of the VCU can meet the deceleration request of the intelligent driving controller, the intelligent driving controller directly requests negative torque from the VCU. Since negative torque belongs to motor-wire braking, it can avoid unevenness, overshoot, non-linearity and other situations caused by ESP hydraulic braking.

[0038] This solution provides a car, which adopts the negative torque longitudinal control method in the above embodiment. Since it includes the negative torque control method in the above embodiment, it has all the characteristics of the solution in the above embodiment, that is, the intelligent driving negative torque longitudinal control method of this solution does not require hardware modification. It is developed through the intelligent driving controller software model. When a small deceleration is requested, it directly requests negative torque from the VCU for braking. Because the negative torque is achieved through the motor, the control is linear. Compared with the previous hydraulic braking, it is more linear and smooth. Improve the comfort of the intelligent driving experience.

[0039] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A method for intelligent driving negative torque longitudinal control, characterized in that: include: After the vehicle intelligent driving function is turned on, if it is detected that the vehicle has a deceleration requirement, the upper intelligent driving controller obtains the energy recovery capability value sent in real time by the VCU and sets the corresponding maximum supported threshold value T1 of the negative torque; Calculate the target negative torque value T2 corresponding to the deceleration requirement; Set the calibrable switching interval torque value △T; According to the values ​​of T1, T2 and △T, the intelligent driving controller sends a negative torque request to the VCU or directly requests deceleration to the ESP through the intelligent driving controller to meet the deceleration demand.

2. The method for intelligent driving negative torque longitudinal control according to claim 1, characterized in that: The calibratable switching interval torque value △T is set to meet the requirement: 0<|T2|+△T<|T1|.

3. The method for intelligent driving negative torque longitudinal control according to claim 1, characterized in that: When |T2|>|T1|, the intelligent driving controller directly requests deceleration from ESP. Otherwise, the relationship between |T2|-△T and |T1| is judged. When |T2|-△T<|T1|, the intelligent driving controller directly sends a negative torque request to VCU.

4. The method for intelligent driving negative torque longitudinal control as claimed in claim 3, characterized in that: When |T2|-△T<|T1|, the relationship between |T2|+△T and |T1| is judged in real time. When |T2|+△T≥|T1|, the intelligent driving controller exits and directly sends a negative torque request to the VCU, and the intelligent driving control directly requests deceleration from the ESP.

5. The method for intelligent driving negative torque longitudinal control according to claim 4, characterized in that: When |T2|-△T<|T1|, the relationship between |T2|+△T and |T1| is judged in real time. When |T2|+△T<|T1|, it is judged whether the intelligent driving function is exited. If so, the deceleration demand ends. If not, the maximum supportable threshold value T1 and target negative torque value T2 of negative torque are continuously monitored and updated, and negative torque requests are continuously issued to VCU through the intelligent driving controller based on T1, T2 and △T values, or deceleration is directly requested to ESP through the intelligent driving controller to meet the deceleration demand.

6. The method for intelligent driving negative torque longitudinal control according to any one of claims 1 to 5, characterized in that: The calculation of the target negative torque value T2 includes: calculating the target deceleration value a1; and converting the target deceleration value into the target negative torque value T2 through a deceleration and torque model.

7. The method for intelligent driving negative torque longitudinal control according to claim 6, characterized in that: The calculation of the target negative torque value T2 also includes real-time acquisition of the current vehicle speed, accelerometer signal, and slope signal, and calculation of the target deceleration value a1 based on the current vehicle speed, accelerometer signal, and slope signal.

8. The method for intelligent driving negative torque longitudinal control according to any one of claims 1 to 5, characterized in that: The intelligent driving controller directly sends a negative torque request to the VCU and simultaneously corrects the negative torque request value in real time through the PI control model to achieve the purpose of vehicle deceleration.

9. A car, characterized in that: The automobile performs negative torque longitudinal control of the automobile using the method for intelligent driving negative torque longitudinal control as described in any one of claims 1-8.

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