阅读说明：本技术 一种适用于新能源商用车驱动扭矩控制系统及控制方法 (Driving torque control system and method suitable for new energy commercial vehicle ) 是由 杨维刚 杨志超 张学锋 于 2020-12-31 设计创作，主要内容包括：一种适用于新能源商用车驱动扭矩控制系统及控制方法,涉及新能源汽车领域,解决现有扭矩控制方法在出现扭矩突变时,最大扭矩受限,易出现传动系统部件易断裂故障等问题,包括挡位处理模块、油门踏板处理模块、制动踏板处理模块、系统最大能力模块、故障处理模块、驱动扭矩控制模块、扭矩仲裁模块和信号输出模块,本发明方法中,加速踏板开度信号数据采集密集方式优化,减少软件处理过程中的数据查询,提高运算速率,未覆盖的参数采用线差值计算,保证数据采集及处理平顺性。采用逐次滤波算法,防止扭矩输出发生突变。增加扭矩平滑控制,对需求扭矩进行转矩增加率进行限制,防止“敲齿Clunk”现象发生,避免产生不良乘坐感受和降低传动系统寿命。(The invention discloses a driving torque control system and a driving torque control method suitable for a new energy commercial vehicle, relates to the field of new energy vehicles, and solves the problems that the maximum torque is limited and transmission system components are easy to break and the like when the torque suddenly changes in the existing torque control method. And a successive filtering algorithm is adopted to prevent the torque output from sudden change. Torque is increased for smooth control, torque increasing rate of the required torque is limited, the phenomenon of 'knocking gear' is prevented, poor riding feeling is avoided, and the service life of a transmission system is shortened.)

1. A driving torque control system suitable for a new energy commercial vehicle comprises a gear processing module, an accelerator pedal processing module, a brake pedal processing module, a system maximum capacity module, a fault processing module, a driving torque control module, a torque arbitration module and a signal output module;

the driving torque control modules respectively receive gearsThe system comprises a logic gear signal output by a position processing module, an accelerator pedal signal output by an accelerator pedal processing module, a brake pedal signal output by a brake pedal processing module, a battery SOC value, a battery pack total voltage, a fault state signal and a battery pack current maximum allowable feedback current output by a BMS (battery management system), and a driving torque T output by a system maximum capacity module under the current state of a motor under the current state_MCUDriving torque T of the battery at the present state_BMSMaximum torque T of transmission system_{Transmission system}And fault limit value T output by fault processing module_{Fault limit}(ii) a And a torque signal is output to the torque arbitration module, and the torque arbitration module outputs a torque request signal to the MCU through the signal output module to realize torque control.

2. The system of claim 1, wherein the torque control system is adapted for use with a new energy commercial vehicle, and comprises: the system maximum capacity module is used for limiting the maximum driving capacity torque of the system, namely: the value of the maximum driving capacity torque of the system is the torsion resistance torque of the part with the minimum torsion resistance in the whole transmission system.

3. The system of claim 1, wherein the torque control system is adapted for use with a new energy commercial vehicle, and comprises: when the whole vehicle has a fault, the fault limit value T output by the fault processing module_{Fault limit}＝T_{Maximum power of MCU}The fault limit coefficient specifically comprises the following calculation processes:

system capability estimation drive torque T_{Maximum power of MCU}＝min(T_MCU，T_BMS，T_{Transmission system}，T_{Fault limit})

In the formula, T_MCUThe driving torque which can be generated under the current state of the motor can be calibrated according to the external characteristics of the motor:

T_MCU＝T_{motor limiting}

The T is_{Motor limiting}The inquiry is made according to the external characteristics of the motor,

T_BMSis the driving torque which can be borne by the current state of the battery and is reflected in real time according to the BMSCurrent maximum discharge power P of battery pack_peakAnd calculating the current rotating speed to obtain:

P_peakcurrent maximum allowable discharge current x total voltage of battery pack

T_BMS＝P_peak*9550/n

T_{Transmission system}The maximum torque that the transmission system can bear is determined according to the structure of the transmission system.

4. The control method of the driving torque control system of the new energy commercial vehicle as claimed in claim 1, wherein: the method is realized by the following steps:

step one, powering on a system;

step two, the driving torque control module receives the logic gear signal, the accelerator pedal signal, the brake pedal signal, the vehicle speed signal and the motor rotating speed signal, calculates driving torque and sends the torque signal to the torque arbitration module;

thirdly, the torque arbitration module carries out filtering calculation on the received torque signal and outputs an arbitrated torque request signal;

step four, judging whether the ignition key closes IG OFF, if not, returning to the step two; if so, the MCU outputs 0 torque according to the received torque request signal.

5. The control method according to claim 4, characterized in that: in the second step, in the process that the driving torque control module carries out calculation according to the received signals, the VCU detects that a brake pedal is stepped on, and the acceleration torque is set to be 0; when the hand brake signal is effective, the torque of the maximum driving capacity of the limiting system is linearly reduced to 20% according to the torque smooth control, and the combined instrument gives an alarm to a driver.

6. The control method according to claim 4, characterized in that: in the third step, the torque arbitration module applies a successive filtering algorithm to the received torque signal and performs torque smoothing control on the received torque signal, which is expressed by the following formula:

and adopting a formula Ta-K delta T/delta T, wherein K is a constant, Ta is a target output torque value, delta T is system sampling time, and delta T is a torque demand value minus a torque output value at the previous moment.

Technical Field

The invention relates to the field of new energy automobiles, in particular to a driving torque control system and a driving torque control method suitable for a new energy commercial vehicle.

Background

Electric driving is an important development direction of new energy automobiles. In recent years, pure electric vehicles, fuel cell vehicles and hybrid electric vehicles are all rapidly developed in parallel. The driving core control technology is mastered, the dynamic property, the stability and the efficiency of the whole vehicle are influenced, and the driving torque control is an important link of the electric driving control technology of the whole vehicle.

The prior art is as follows:

the driving torque control has the function that when a vehicle normally runs, the VCU receives an accelerator pedal position signal (an accelerator pedal APS2 signal and an accelerator pedal APS1 signal), a brake pedal signal (a brake pedal sensor signal and a foot brake switch), gear signals (N gear, D gear and R gear) and a motor speed signal (MCU _ MotorSpeed) to explain driving intentions, generate related torque requirements, transmit the torque requirements to the MCU and convert electric energy in a power battery into kinetic energy of the vehicle through the motor.

In the existing torque control strategy, data is dense in the process of acquiring input signals, the processing load of a controller is increased, and the operation rate is influenced; during torque output control, the situation of torque sudden change can occur when the driver steps on an accelerator pedal and operates abnormally (steps on and releases suddenly); without taking into account the maximum torque limit at the time of design, a failure may occur in which some component in the transmission system is easily broken.

Disclosure of Invention

The invention provides a driving torque control system and a driving torque control method suitable for a new energy commercial vehicle, aiming at solving the problems that the maximum torque is limited and the transmission system part is easy to break and the like when the torque is suddenly changed in the existing torque control method.

A driving torque control system suitable for a new energy commercial vehicle comprises a gear processing module, an accelerator pedal processing module, a brake pedal processing module, a system maximum capacity module, a fault processing module, a driving torque control module, a torque arbitration module and a signal output module;

the driving torque control module respectively receives the logic gear signal output by the gear processing module and the accelerator pedal signal output by the accelerator pedal processing moduleThe brake pedal signal output by the movable pedal processing module, the battery SOC value, the battery pack total voltage, the fault state signal and the current maximum allowable feedback current of the battery pack output by the BMS, and the driving torque T of the motor under the current state output by the system maximum capacity module_MCUDriving torque T of the battery at the present state_BMSMaximum torque T of transmission system_{Transmission system}And fault limit value T output by fault processing module_{Fault limit}(ii) a And the torque arbitration module outputs a torque signal to the torque arbitration module, and the torque arbitration module outputs a torque request signal to the MCU through the signal output module.

A driving torque control method suitable for a new energy commercial vehicle is realized by the following steps:

step one, powering on a system;

step two, the driving torque control module receives the logic gear signal, the accelerator pedal signal, the brake pedal signal, the vehicle speed signal and the motor rotating speed signal, calculates driving torque and sends the torque signal to the torque arbitration module;

thirdly, the torque arbitration module carries out filtering calculation on the received torque signal and outputs an arbitrated torque request signal;

step four, judging whether the ignition key closes IG OFF, if not, returning to the step two; if so, the MCU outputs 0 torque according to the received torque request signal.

The invention has the beneficial effects that: in order to achieve the purpose, the invention develops the driving torque control method of the new energy commercial vehicle by analyzing various operation conditions of the whole vehicle and the requirements of the torque in the running process of the whole vehicle. And the verification is carried out in the real vehicle, and the control scheme and the technical parameters are continuously optimized. After the test verification of more than one year, the driving torque control strategy is finally formed.

The control method has the following advantages:

(1) data query in the software processing process is reduced, the operation rate is improved, and the smoothness of torque output is ensured.

(2) By limiting the maximum driving capacity torque of the system, all parts in the transmission system are protected in the mechanical impact process.

(3) And the control strategy ensures that the braking is preferentially executed, and the safety of the whole vehicle is ensured.

(4) And the data output is prevented from sudden change through a control strategy, and the torque output is ensured to be stable.

(5) The torque increasing rate of the required torque is limited, the phenomenon of 'knocking gear' is prevented, poor riding feeling is avoided, and the service life of a transmission system is shortened.

(6) The maximum speed is limited, and the safety of the whole vehicle is ensured.

Drawings

FIG. 1 is a schematic block diagram of a driving torque control method for a new energy commercial vehicle according to the present invention.

FIG. 2 is a flow chart of a driving torque control method for a new energy commercial vehicle according to the present invention.

Detailed Description

The first embodiment is described with reference to fig. 1 and 2, and a driving torque control system suitable for a new energy commercial vehicle comprises a gear processing module, an accelerator pedal processing module, a brake pedal processing module, a system maximum capacity module, a fault processing module, a driving torque control module, a torque arbitration module and a signal output module;

the driving torque control module receives a logic gear signal output by the gear processing module, an accelerator pedal signal output by the accelerator pedal processing module, a brake pedal signal output by the brake pedal processing module, a battery SOC value, a battery pack total voltage, a fault state signal and a current maximum allowable feedback current of the battery pack output by the BMS, and a driving torque T output by the system maximum capacity module under the current state of the motor_MCUDriving torque T of the battery at the present state_BMSMaximum torque T of transmission system_{Transmission system}And fault limit value T output by fault processing module_{Fault limit}(ii) a And the torque arbitration module outputs a torque signal to the torque arbitration module, and the torque arbitration module outputs a torque request signal to the MCU through the signal output module.

In the embodiment, the vehicle control unit VCU obtains a torque coefficient according to different accelerator pedal opening degrees and vehicle speeds and according to a formula y ═ a × x ^2+ b × x, wherein x is the brake pedal opening degree and the value range is [0,1], and the values of a and b are values determined after the vehicle meets the requirements of subjective evaluation by pressing the brake pedal at different vehicle speeds to evaluate the deceleration of the vehicle. Different torque coefficients MAP are corresponding to different gears and driving modes.

The required acceleration torque coefficient is obtained by looking up a table (see tables 1 and 2), different MAPs exist under different gears and driving modes, a data area is not embodied in the table, a linear interpolation method is adopted for calculation, the problem that data acquisition is intensive when the VCU processes an opening signal of an accelerator pedal is solved, data query in a software processing process is reduced, the operation rate is improved, and the smoothness of torque output is ensured.

TABLE 1D drive coefficient Table (TBD)

Note: line difference calculations were used for the parameters not covered in the table above.

TABLE 2R gear drive coefficient Table (TBD)

Note: line difference calculations were used for the parameters not covered in the table above.

In the present embodiment, the maximum driving capability torque of the system is limited, that is: the value of the maximum driving capacity torque of the system is the torsion resistance torque of the part with the minimum torsion resistance in the whole transmission system;

when the whole vehicle has a fault, T_{Fault limit}＝T_{Maximum power of MCU}All cause ofThe barrier value coefficient is specifically as follows:

the system capacity estimation driving torque refers to the maximum driving torque which can be borne by the whole vehicle system under the current state, and the following factors are mainly confirmed;

system capability estimation drive torque T_{Maximum power of MCU}＝min(T_MCU，T_BMS，T_{Transmission system}，T_{Fault limit})

In the formula, T_MCUThe driving torque which can be generated under the current state of the motor can be calibrated according to the external characteristics of the motor:

T_MCU＝T_{motor limiting}

The T is_{Motor limiting}The motor is inquired according to the external characteristics of the motor, a motor manufacturer can provide an external characteristic table of the motor, the current motor rotating speed is known in real time, and the maximum torque value of the motor, namely T_{Motor limiting}。

T_BMSThe driving torque which can be borne by the battery under the current state is the current maximum discharging power P of the battery pack fed back by the BMS in real time_peak(the maximum allowable discharge current is calculated from the total voltage of the battery pack) and the current rotating speed are calculated as follows:

P_peakcurrent maximum allowable discharge current x total voltage of battery pack

T_BMS＝P_peak*9550/n

T_{Transmission system}The maximum torque that the driveline can withstand is determined based on the driveline configuration (non-regenerative).

T_{Fault limit}Is composed of

T_{Fault limit}＝T_{Maximum power of MCU}Fault limit coefficient

The fault limit coefficient is provided by a fault handling module.

The second embodiment is described with reference to fig. 2, and the second embodiment is a control method suitable for a driving torque control system of a new energy commercial vehicle, which is described in the first embodiment and specifically implemented by the following steps:

step one, powering on a system;

step two, the driving torque control module receives the logic gear signal, the accelerator pedal signal, the brake pedal signal, the vehicle speed signal and the motor rotating speed signal, calculates driving torque and sends the torque signal to the torque arbitration module;

thirdly, the torque arbitration module carries out filtering calculation on the received torque signal and outputs an arbitrated torque request signal;

step four, judging IG OFF, if not, returning to the step two; if so, the MCU outputs 0 torque according to the received torque request signal.

In the second step of the embodiment, the braking is guaranteed to be executed preferentially by a control strategy, so that the safety of the whole vehicle is guaranteed. In the driving torque analysis process of the driving torque control module, the VCU detects that a brake pedal is stepped on, and the acceleration torque demand is set to be 0; when the hand brake signal is effective, the torque of the maximum driving capacity of the limiting system is linearly reduced to 20% according to torque smooth control (the maximum value is subjected to linear limit value according to a value of 20%), and the combined instrument gives an alarm to a driver to prevent the hand brake shoe from being heated and ablated when large torque is output.

In the third step of the embodiment, the data output is prevented from sudden change through a control strategy, and the torque output is ensured to be stable.

In order to ensure the torque safety, the torque arbitration module filters when the torque changes, and adopts a successive filtering algorithm as follows:

10 numbers x1 and x2 … x10 are collected for the first time, an average value A1 is obtained, x11 is collected at the next moment, if | x11-A1| > is the standard quantity limit, x11 is discarded, if | x11-A1| < > is the standard quantity limit, x2 and x3 … x11 are reserved, A2 … is obtained, and the size of the standard quantity limit is adjusted according to the effect of the real vehicle.

And performing torque smoothing control on the received torque signal, wherein the torque smoothing control is represented by the following formula:

and adopting a formula Ta-K delta T/delta T, wherein K is a constant, Ta is a target output torque value, delta T is system sampling time, and delta T is a torque demand value minus a torque output value at the previous moment.

Torque is increased for smooth control, torque increasing rate of the required torque is limited, the phenomenon of 'knocking gear' is prevented, poor riding feeling is avoided, and the service life of a transmission system is shortened. The torque smooth control adopts a formula Ta-K delta T/delta T, wherein K is a constant, Ta is a target output torque value, and delta T is a torque demand value minus a torque output value at the previous moment. At is the sampling time of the system and can typically be 10ms or 100 ms.

In the embodiment, the highest vehicle speed limit is added, the highest vehicle speed of the R gear and the highest vehicle speed under the D gear are limited, the highest vehicle speed of the D gear is limited to 90km/h (TBD), when the vehicle speed is equal to 90km/h, the torque is reduced to zero by adjusting with P as the slope through increment PI adjustment, and the effect of limiting the vehicle speed is achieved. The highest speed of the R gear is limited to 15km/h, when the speed is 15km/h, the torque is reduced to zero by adjusting with P as a slope through increment PI adjustment, and the effect of limiting the speed is achieved.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.