Method for determining maximum value of torque control vehicle speed correction rate of electric vehicle and electronic equipment

Abstract

The invention discloses a method for determining the maximum value of a torque control vehicle speed correction rate of an electric vehicle and electronic equipment. The method comprises the following steps: acquiring the maximum change value of the acceleration of a motor in a predetermined preset period; according to the maximum change value of the acceleration of the motor and the vehicle parameters, the maximum change value and the torsion angle of the driving end torque of the vehicle are calculated; calculating the maximum change rate of the torque of the driving shaft based on the maximum change value of the torque of the driving end, the torsion angle and the tooth clearance; a rate maximum rate of change is calculated based on the driveshaft torque maximum rate of change. According to the method, the proper maximum change rate of the speed is determined based on the maximum change value of the acceleration of the motor and in combination with vehicle parameters such as the tooth clearance, the drivability impact and tooth hitting phenomena are effectively avoided, the driving comfort is improved, on the premise that it is guaranteed that drivability impact is not generated, the maximum possible rate correction is achieved, the torque continuous control function is perfected, and the driving safety is improved. And the overall driving experience of the driver is improved. And the maximum change rate of the rate is determined through a scientific calculation method, so that the control process is more accurate and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, and in particular to a method for determining a maximum correction rate of a vehicle speed in torque control of an electric vehicle, an electronic device, a storage medium, and a computer program product. BACKGROUND

[0002] An electric vehicle (also known as a new energy vehicle) is a vehicle that is driven by an electric motor. During driving, the working state of the electric motor directly affects the power output.

[0003] In the prior art, the output torque of the electric motor is controlled mainly according to the opening degree of an accelerator pedal (throttle pedal) and the vehicle speed. However, in order to improve the driving experience, in a specific mode, the target torque of the electric motor can also be determined based on a corrected vehicle speed to adjust the output torque of the electric motor.

[0004] For example, during driving of the electric vehicle, the output characteristic of the electric motor is a constant torque output below a base speed and enters a constant power region above the base speed, and the electric motor outputs torque in a constant power manner. As the vehicle speed increases, the output torque of the electric motor gradually decreases because the power of the electric motor is constant.

[0005] This characteristic causes the driver to feel that the power of the vehicle continues to weaken when the driver keeps the accelerator pedal depressed at a constant depth, which affects the driving experience and maneuverability.

[0006] Therefore, a fixed vehicle speed can be sent to a vehicle control module (VCM), the target torque is calculated by the VCM, and the target torque is input to the motor controller of the electric motor. The motor controller controls the torque output of the electric motor based on the target torque, so that the output torque of the electric motor remains unchanged when the vehicle speed increases, thereby avoiding the problem that the output torque of the electric motor decreases when the vehicle speed increases.

[0007] However, when it is necessary to exit the specific mode, it is necessary to adjust the corrected vehicle speed to the actual vehicle speed and output it to the VCM. For example, during the torque consistency control process, when the output torque of the electric motor contacts the maximum output characteristic curve of the electric motor, the corrected vehicle speed needs to be corrected to the actual vehicle speed to avoid exceeding the maximum output characteristic of the electric motor and causing a fault.

[0008] However, if the correction rate is too fast, the torque will change too quickly, causing driving shock and tooth clashing, which affects driving comfort and the service life of the transmission system. If the correction rate is too slow, the operation of the accelerator pedal will become poor, and the phenomenon of early throttle opening will occur, which is not consistent with the habits of the driver and reduces the driving experience.

[0009] Therefore, there is a lack of a reasonable method for calculating the correction rate in the prior art. SUMMARY

[0010] Therefore, it is necessary to provide an electric vehicle torque control vehicle speed correction rate maximum value determination method, electronic equipment, storage medium and computer program product in view of the technical problem that the prior art lacks a reasonable correction rate calculation method.

[0011] The present application provides an electric vehicle torque control vehicle speed correction rate maximum value determination method, comprising: obtaining a predetermined maximum change value of motor acceleration in a predetermined period; According to the maximum change value of the motor acceleration and the vehicle parameters, the maximum change value of the driving end torque and the torsion angle of the vehicle are calculated. Based on the maximum change value of the driving end torque, the torsion angle and the tooth gap, the maximum change rate of the driving shaft torque is calculated. Based on the maximum change rate of the driving shaft torque, the maximum change rate of the speed is calculated, which is the maximum value of the correction rate change rate, the correction rate change rate is used to correct the corrected speed to the actual speed, the vehicle determines the target torque of the driving motor based on the lock speed in the preset mode, and when the preset condition is met, the lock speed is adjusted by the correction rate change rate to obtain the corrected speed and determine the target torque of the driving motor based on the corrected speed, until the corrected speed is less than or equal to the actual speed.

[0012] Further, the maximum change value of the driving end torque and the torsion angle of the vehicle are calculated according to the maximum change value of the motor acceleration and the vehicle parameters, comprising: According to the maximum change value of the motor acceleration, the vehicle mass and the driving shaft radius, the maximum change value of the driving end torque is calculated. Based on the maximum change value of the driving end torque and the torsion stiffness, the torsion angle is calculated. Further, the maximum change rate of the driving shaft torque is calculated based on the maximum change value of the driving end torque, the torsion angle and the tooth gap, comprising: Based on the maximum change value of the driving end torque and the torsion angle, the maximum work of the driving end is calculated. Based on the maximum work of the driving end and the tooth gap, the maximum force of the driving shaft is calculated. The maximum force of the driving shaft is multiplied by the radius of the driving shaft to obtain the maximum change amount of the driving shaft torque. The maximum change amount of the driving shaft torque is divided by the time length of the predetermined period to obtain the maximum change rate of the driving shaft torque.

[0013] Further, the maximum force of the driving shaft is calculated based on the maximum work of the driving end and the tooth gap, comprising: The maximum force of the driving shaft is calculated as the maximum work of the driving end divided by the tooth gap.

[0014] Further, the calculating the maximum change rate of the speed based on the maximum change rate of the driving shaft torque comprises: calculating the maximum change rate of the wheel end torque based on the maximum change rate of the driving shaft torque; calculating the maximum change rate of the speed based on the maximum change rate of the wheel end torque.

[0015] Further, the calculating the maximum change rate of the wheel end torque based on the maximum change rate of the driving shaft torque comprises: multiplying the maximum change rate of the driving shaft torque by a transmission efficiency to obtain the maximum change rate of the wheel end torque.

[0016] Further, the calculating the maximum change rate of the speed based on the maximum change rate of the wheel end torque comprises: dividing the maximum change rate of the wheel end torque by a tire radius to obtain the maximum change rate of the wheel end torsion force; dividing the maximum change rate of the wheel end torsion force by a total vehicle mass to obtain the maximum change rate of the speed.

[0017] The present application provides an electronic device, comprising: at least one processor; and, a memory connected to the at least one processor in communication; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method for determining the maximum value of the speed correction rate of the electric vehicle torque control as described above.

[0018] The present application provides a storage medium storing computer instructions for performing all steps of the method for determining the maximum value of the speed correction rate of the electric vehicle torque control as described above when the computer executes the computer instructions.

[0019] The present application provides a computer program product comprising computer programs / instructions, which, when executed by a processor, implement the method for determining the maximum value of the speed correction rate of the electric vehicle torque control as described above.

[0020] The present application determines a suitable maximum change rate of the speed based on the maximum change value of the motor acceleration and in combination with vehicle parameters such as the gear backlash, effectively avoids driving impact and gear tooth phenomenon, improves driving comfort, realizes the maximum possible correction rate under the premise of ensuring no driving impact, perfects the torque persistence control function, and improves the overall driving experience of the driver. The scientific calculation method for determining the maximum change rate of the speed makes the control process more accurate and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A work flow chart of a maximum value determination method of a vehicle speed correction rate of a torque control of an electric vehicle according to an embodiment of the present application; Figure 2 A work flow chart of a maximum value determination method of a vehicle speed correction rate of a torque control of an electric vehicle according to another embodiment of the present application; Figure 3 A schematic diagram of a motor torque-vehicle speed curve according to an embodiment of the present application; Figure 4 A schematic diagram of a driving gear and a driven gear according to an embodiment of the present application; Figure 5 A schematic diagram of a hardware structure of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] The specific embodiments of the present application will be further described below with reference to the accompanying drawings. Identical parts are denoted by identical reference numerals in the description below. It should be noted that the words “front”, “back”, “left”, “right”, “up” and “down” used in the following description refer to the directions in the drawings, and the words “inner” and “outer” refer to the directions towards or away from the geometric center of a particular part.

[0023] As Figure 1 shown is a work flow chart of a maximum value determination method of a vehicle speed correction rate of a torque control of an electric vehicle according to an embodiment of the present application, comprising: Step S101, obtaining a maximum acceleration change value of a motor in a predetermined period; Step S102, calculating a maximum change value of a driving end torque and a torsion angle of a vehicle according to the maximum acceleration change value of the motor and vehicle parameters; Step S103, calculating a maximum change rate of a driving shaft torque based on the maximum change value of the driving end torque, the torsion angle and a gear clearance; Step S104, calculating a maximum change rate of a speed rate based on the maximum change rate of the driving shaft torque, the maximum change rate of the speed rate being a maximum value of a correction rate change rate, the correction rate change rate being used to correct a vehicle speed to an actual vehicle speed, the vehicle determining a target torque of a driving motor based on a lock speed in a predetermined mode, and when a predetermined condition is met, adjusting the lock speed by the correction rate change rate to obtain a corrected vehicle speed and determining the target torque of the driving motor based on the corrected vehicle speed until the corrected vehicle speed is less than or equal to the actual vehicle speed.

[0024] Specifically, the present application can be applied to electronic devices with processing capabilities, and can be applied to computers.

[0025] The vehicle parameters of different vehicle models can be determined in advance according to different vehicle models, the maximum change rate of the speed is determined by using the maximum correction rate of the electric vehicle torque control speed, the correction rate is designed on the basis that the correction rate is less than the maximum change rate of the speed, and the correction rate is written into the electronic controller of the vehicle.

[0026] The correction rate is used for correcting the corrected speed to the actual speed, and the vehicle determines the target torque of the drive motor based on the lock speed in the preset mode.

[0027] Specifically, the target torque of the drive motor is determined based on the lock speed, including: sending the lock speed to the vehicle control module (VCM), calculating the target torque by the VCM, and inputting the target torque into the motor controller of the drive motor, and the motor controller controls the torque output of the drive motor based on the target torque.

[0028] Then, when the vehicle meets the preset condition, the lock speed is adjusted at the correction rate to obtain the corrected speed, and the target torque of the drive motor is determined based on the corrected speed.

[0029] Specifically, the target torque of the drive motor is determined based on the corrected speed, including: sending the corrected speed to the VCM, calculating the target torque by the VCM, and inputting the target torque into the motor controller of the drive motor, and the motor controller controls the torque output of the drive motor based on the target torque until the corrected speed is less than or equal to the actual speed.

[0030] In some embodiments, the lock speed is adjusted at the correction rate to obtain the corrected speed, including: The corrected speed at the i-th moment is calculated as: V 修i =V 锁 +A×t i , wherein V 修i is the corrected speed at the i-th moment, V 锁 is the lock speed, A is the correction rate, and t is the time length from the start of the change to the i-th moment.

[0031] As an example, at a certain speed, the driver steps on the accelerator pedal to a certain depth and keeps it unchanged. The output torque of the motor will be affected by the accelerator pedal and the speed. In order to avoid the problem of increasing speed but reducing the output torque of the motor. The following torque control method can be used, including: Monitoring the accelerator pedal, judging whether the stepping depth of the accelerator pedal and / or the stepping speed of the accelerator pedal meets the starting condition, the starting condition being: the stepping depth of the accelerator pedal is greater than or equal to the starting stepping depth threshold, and / or the stepping speed of the accelerator pedal is greater than or equal to the stepping speed threshold. When the acceleration pedal depression depth and / or the acceleration pedal depression speed meets the starting condition, the vehicle speed at which the acceleration pedal depression depth and / or the acceleration pedal depression speed meets the starting condition is recorded as the lock speed; The target torque of the drive motor is determined based on the lock speed.

[0032] In some embodiments, the target torque of the drive motor is determined based on the lock speed by inputting the lock speed to a vehicle control module, calculating the target torque by the vehicle control module, inputting the target torque to a motor controller of the drive motor, and controlling the torque output of the drive motor by the motor controller based on the target torque.

[0033] By gradually adjusting the input vehicle speed to the VCM to be consistent with the actual vehicle speed at a preset speed when the pedal depression depth or the motor state meets the exit condition, the impact caused by torque mutation is avoided, and the driving comfort and safety are improved.

[0034] Then, the acceleration pedal depression depth and / or the motor state of the drive motor need to be monitored to determine whether the pedal depression depth and / or the motor state meets the exit condition. The exit condition includes: the acceleration pedal depression depth is less than or equal to the exit pedal depression depth threshold, or the output torque of the drive motor multiplied by the actual vehicle speed is greater than or equal to the maximum power of the output torque of the drive motor. When the pedal depression depth or the motor state meets the exit condition, the lock speed is gradually increased to obtain a corrected speed at a preset speed. If the corrected speed is less than the actual vehicle speed, the target torque of the drive motor is determined based on the corrected speed. If the corrected speed is greater than or equal to the actual vehicle speed, the target torque of the drive motor is determined based on the actual vehicle speed.

[0035] Specifically, as shown in Figure 3 The pedal map 300 includes a plurality of torque curves at different throttle openings. During the process of maintaining the motor output torque, as shown in Figure 3As shown in curve 301, the actual vehicle speed is always increasing, and when the actual vehicle speed multiplied by the torque force of the motor output is equal to the power corresponding to the maximum external characteristic curve 302 of the motor output torque, i.e., the motor has reached the maximum power, at this time the driver cannot increase the torque even if the accelerator pedal is stepped on, and there is a safety risk. Therefore, at this time, the exit mechanism is triggered, and the lock speed is changed to the actual vehicle speed, so that the control of the accelerator pedal returns to the normal state. Then under the control of the external characteristic of the accelerator pedal opening, the increase of the vehicle speed will cause the decrease of the torque output by the motor, so as to keep the power from breaking through the maximum external characteristic of the motor, while ensuring the power and realizing the safe use of the motor. That is, when the output torque force of the driving motor multiplied by the actual vehicle speed is greater than or equal to the power of the maximum external characteristic of the driving motor output torque, it is judged that the exit condition is met.

[0036] Wherein, the output torque force of the driving motor is the output torque / proportionality coefficient. The proportionality coefficient is preferably 9550.

[0037] When it is judged that the pedal depression depth or the motor state meets the exit condition, the lock speed is controlled to gradually increase to obtain a modified speed.

[0038] Specifically, the modified speed is calculated as: V 修 = V 锁 + A x t, wherein, V 修 is the modified speed, V 锁 is the lock speed, A is the modified rate, and t is the time elapsed since it is judged that the pedal depression depth or the motor state meets the exit condition.

[0039] The modified speed is calculated every interval of time, and the calculated modified speed is compared with the actual vehicle speed. If the modified speed is less than the actual vehicle speed, the target torque of the driving motor is determined based on the modified speed; if the modified speed is greater than or equal to the actual vehicle speed, the target torque of the driving motor is determined based on the actual vehicle speed, and the calculation of the modified speed is stopped, and then the target torque of the driving motor is determined based on the actual vehicle speed.

[0040] In some embodiments, the target torque of the driving motor is determined based on the modified speed by inputting the modified speed into a vehicle control module, calculating the target torque by the vehicle control module, inputting the target torque into a motor controller of the driving motor, and controlling the torque output of the driving motor based on the target torque by the motor controller.

[0041] In some embodiments, the target torque of the driving motor is determined based on the actual vehicle speed by inputting the actual vehicle speed into a vehicle control module, calculating the target torque by the vehicle control module, inputting the target torque into a motor controller of the driving motor, and controlling the torque output of the driving motor based on the target torque by the motor controller.

[0042] The above control method is just an example, in fact, the preset mode can also be other modes of locking vehicle speed.

[0043] The above control method is just an example, in fact, the preset mode can also be other modes of locking vehicle speed.

[0044] When the vehicle is working in the preset mode, the vehicle control system sends the locking vehicle speed to the VCM to control the output torque of the drive motor. When the preset exit mode condition is met, the locking vehicle speed is corrected at a maximum rate of change that does not exceed the calculated rate of change, to obtain a new corrected vehicle speed and send it to the VCM, until the corrected vehicle speed is less than or equal to the actual vehicle speed.

[0045] The effects of different correction rates are as follows: Too fast correction rate: the motor is controlled by the accelerator pedal and the vehicle speed. The control of the accelerator pedal is proportional, so the impact on the driver's driving performance will be smaller. The vehicle speed is the result of the integration of acceleration. If the acceleration is very large, i.e. the speed changes quickly, the output torque of the motor will become very fast. For the driver, in the process of maintaining the accelerator pedal, the power of the whole vehicle will decrease rapidly, which is very poor for the driving experience of the driver. At the same time, due to the rapid decrease of the torque, the rotation speed of the drive shaft will be smaller than that of the transmission shaft, resulting in a gap between them, and the occurrence of gear teeth, which is called driving impact.

[0046] The extreme of the correction speed being too slow to correct the actual vehicle speed to the corrected vehicle speed can be considered as no correction, that is, the motor is always controlled by the corrected vehicle speed, but due to the influence of the motor external characteristic, the torque of the motor cannot always remain unchanged, but can only be output along the maximum external characteristic of the motor. This phenomenon will cause that, as long as the driver successfully triggers the function, no matter how much the accelerator pedal is stepped on, as long as the driving time is long enough, the motor will always output torque along the maximum external characteristic. However, in fact, the maximum external characteristic curve of the motor corresponds to the accelerator pedal of 100%, that is, as long as the driver steps on the accelerator pedal to 100%, the motor will also output along the maximum external characteristic of the motor. That is, the driver randomly steps on an accelerator pedal to output 100% torque, and when the driver continues to step on the accelerator pedal to accelerate, the motor has no ability to output torque, that is, the phenomenon of early opening of the accelerator occurs, which is not consistent with the driver's usual driving habits. Therefore, if the correction is too slow, there will be no torque output or too small torque output when the driver steps on the accelerator pedal to accelerate.

[0047] As can be seen from the above, both the correction speed being too fast and the correction speed being too slow will cause problems in driving performance. Therefore, the maximum value of the correction speed of the torque control vehicle speed of the electric vehicle provided by the present application can achieve a balance between the two. First, too fast change will cause problems in driving performance, therefore, the reasonable vehicle speed is to be designed near the boundary value that will not cause driving performance impact, so that the driving performance impact caused by gear teeth can be guaranteed, and at the same time, the maximum value of the correction speed can be guaranteed, and the phenomenon of early opening of the accelerator can not exist for a long time, and the driving experience of the driver can be guaranteed. The boundary value of the driving performance needs to introduce the boundary G value concept of the driving performance impact. If the acceleration G of the whole vehicle changes less than the maximum change value of the motor acceleration marked in advance within a certain period, the process will not cause driving performance impact.

[0048] Specifically, first, step S101 is performed to obtain the maximum change value of the motor acceleration in a predetermined period.

[0049] The predetermined period is a predetermined time length, which can be set to, for example, 10 milliseconds. The maximum change value of the motor acceleration is pre-marked. The same maximum change value of the motor acceleration is used for all vehicle types. Since motor jitter will cause whole vehicle jitter to affect the performance of the whole vehicle, the maximum change value of the motor acceleration can be pre-marked through multiple tests based on the condition that the motor jitter is minimized.

[0050] Then, step S102 is performed to calculate the maximum change value of the driving end torque and the torsion angle of the vehicle according to the maximum change value of the motor acceleration and the vehicle parameters.

[0051] Specifically, the maximum change in motor acceleration is pre-calibrated and applicable to all vehicle models. Then, based on the specific vehicle parameters for different vehicles, the maximum change in drive-end torque and the torsional angle are calculated. The torsional angle is the angle by which the drive shaft rotates within a preset period under the maximum change in drive-end torque.

[0052] Then, step S103 is executed to calculate the maximum rate of change of the drive shaft torque based on the maximum change value of the drive end torque, the torsion angle, and the tooth backlash.

[0053] Specifically, the drive motor is connected to the driving gear, which meshes with the driven gear. The driven gear is connected to the drive shaft, causing the drive shaft to rotate. The drive shaft then drives the wheels to rotate through the transmission system. The torque at the drive end is the motor torque, while the drive shaft torque is the torque required to rotate the drive shaft caused by the driven wheel. Figure 4 As shown, the tooth clearance 43 is the tooth clearance between the driving gear 41 connected to the drive motor and the driven gear 42 connected to the drive shaft. Based on the maximum change in drive shaft torque, the torsion angle, and the tooth clearance, the maximum rate of change in drive shaft torque is calculated. Below this maximum rate of change in drive shaft torque, the impact of tooth contact between the driving gear 41 and the driven gear 42 is small, acceptable, or imperceptible to humans, thus preventing any drivable impact.

[0054] Finally, step S104 is executed, which calculates the maximum rate of change of speed based on the maximum rate of change of drive shaft torque. The maximum rate of change of speed is the maximum value of the correction rate of change. The correction rate of change is used to correct the vehicle speed to the actual vehicle speed. In a preset mode, the target torque of the drive motor is determined based on the locked vehicle speed. When a preset condition is met, the locked vehicle speed is adjusted with the correction rate of change to obtain the corrected vehicle speed, and the target torque of the drive motor is determined based on the corrected vehicle speed, until the corrected vehicle speed is less than or equal to the actual vehicle speed.

[0055] Specifically, the maximum rate of change of drive shaft torque is converted into the maximum rate of change of speed and then output. After determining the maximum rate of change of speed for the vehicle model, the corrected vehicle speed can be adjusted to achieve an optimal drivability by ensuring it does not exceed the maximum rate of change of speed for that vehicle model.

[0056] This invention, based on the maximum change in motor acceleration and combined with vehicle parameters such as gear backlash, determines a suitable maximum rate of change in speed, effectively avoiding driving shocks and gear slippage, thus improving driving comfort. While ensuring no driving shocks are generated, it achieves the maximum possible correction rate, perfects the torque continuous control function, and enhances the driver's overall driving experience. The maximum rate of change in speed is determined through scientific calculation methods, making the control process more precise and reliable.

[0057] like Figure 2Fig. 1 shows a flowchart of a method for determining a maximum correction rate of a vehicle speed of a torque control of an electric vehicle according to an embodiment of the present application, including: In step S201, a maximum motor acceleration change value in a preset period is obtained.

[0058] In step S202, a maximum driving end torque change value is calculated according to the maximum motor acceleration change value, a vehicle mass, and a driving shaft radius. Based on the maximum driving end torque change value and a torsional stiffness, a torsional angle is calculated.

[0059] In step S203, a maximum driving end work is calculated based on the maximum driving end torque change value and the torsional angle. Based on the maximum driving end work and a gear clearance, a maximum driving shaft force is calculated. The maximum driving shaft force is multiplied by the driving shaft radius to obtain a maximum driving shaft torque change amount. The maximum driving shaft torque change amount is divided by a time length of the preset period to obtain a maximum driving shaft torque change rate.

[0060] In step S204, a maximum wheel end torque change rate is calculated according to the maximum driving shaft torque change rate. According to the maximum wheel end torque change rate, a maximum speed change rate is calculated, the maximum speed change rate being a maximum value of a correction speed change rate, the correction speed change rate being used for correcting a corrected vehicle speed to an actual vehicle speed, a vehicle determining a target torque of a driving motor based on a lockup vehicle speed in a preset mode, and when a preset condition is met, adjusting the lockup vehicle speed to obtain the corrected vehicle speed at the correction speed change rate and determining the target torque of the driving motor based on the corrected vehicle speed until the corrected vehicle speed is less than or equal to the actual vehicle speed.

[0061] Specifically, first, step S201 is performed to obtain a maximum motor acceleration change value in a preset period.

[0062] The preset period is a preset time length, which can be set to, for example, 10 milliseconds. The maximum motor acceleration change value is pre-calibrated. The same maximum motor acceleration change value is used for all vehicle models.

[0063] Then, step S202 is performed to calculate a maximum driving end torque change value according to the maximum motor acceleration change value, a vehicle mass, and a driving shaft radius. Based on the maximum driving end torque change value and a torsional stiffness, a torsional angle is calculated.

[0064] Specifically, first, a maximum driving end torque change value is calculated according to the maximum motor acceleration change value, a vehicle mass, and a driving shaft radius. The calculation formula is: The maximum change value of the driving end torque = the maximum change value of the motor acceleration × the whole vehicle mass × the driving shaft radius.

[0065] Then, the value can be used to calculate the angle of the driving shaft rotating in the period. According to the mechanical principle, torque = torsional stiffness × angle, so the angle of the driving shaft changed because of the maximum change value of the driving end torque is obtained.

[0066] Specifically, based on the maximum change value of the driving end torque and the torsional stiffness, the torsion angle is calculated. The calculation formula is: Torsion angle = the maximum change value of the driving end torque / torsional stiffness. Wherein, the torsional stiffness is a vehicle parameter.

[0067] Then step S203 is performed, based on the maximum change value of the driving end torque and the torsion angle, the maximum work of the driving end is calculated; Based on the maximum work of the driving end and the gear clearance, the maximum stress of the driving shaft is calculated; The maximum stress of the driving shaft is multiplied by the driving shaft radius to obtain the maximum change amount of the driving shaft torque; The maximum change amount of the driving shaft torque is divided by the time length of the preset period to obtain the maximum change rate of the driving shaft torque.

[0068] Specifically, first, based on the maximum change value of the driving end torque and the torsion angle, the maximum work of the driving end is calculated. From the energy formula of the driving shaft torque, energy = torque × torsion angle, so the energy of the driving shaft in the period due to the critical driving impact can be obtained. More specifically, since the driving shaft is twisted, the force will decrease, so a part of the torque will be released, and the entire released elastic performance is the energy of the driving shaft in the entire process, which is the maximum work of the driving end.

[0069] The calculation formula is: The maximum work of the driving end = the maximum change value of the driving end torque × the torsion angle Secondly, based on the maximum work of the driving end and the gear clearance, the maximum stress of the driving shaft is calculated.

[0070] In one embodiment, the calculation of the maximum stress of the driving shaft based on the maximum work of the driving end and the gear clearance comprises: The maximum stress of the driving shaft is calculated as the maximum work of the driving end divided by the gear clearance.

[0071] Specifically, since the drivability problem is to be avoided, the tooth collision is required to be prevented. Assuming that the force is uniformly changed within a preset period. Then the work done = force x distance, for the movement of the driving gear and the driven gear, the distance is the gear gap. Therefore, according to the maximum work done at the driving end and the gear gap, the maximum change value of the acceleration can be calculated to affect the force of the gear, since this force will act on the driven gear and thus on the entire drive shaft, so the force is the maximum force of the drive shaft. The maximum force of the drive shaft is calculated as the maximum work done at the driving end divided by the gear gap.

[0072] The embodiment prevents tooth collision by calculating the maximum force of the drive shaft as the maximum work done at the driving end divided by the gear gap.

[0073] Then, the maximum force of the drive shaft is multiplied by the radius of the drive shaft to obtain the maximum change amount of the drive shaft torque.

[0074] Finally, since the maximum change amount of the drive shaft torque is completed within a preset period, the maximum change amount of the drive shaft torque is divided by the time length of the preset period to obtain the maximum change rate of the drive shaft torque, that is, the maximum change amount of the drive shaft torque per unit time.

[0075] Then step S204 is performed, and the maximum change rate of the wheel end torque is calculated according to the maximum change rate of the drive shaft torque. According to the maximum change rate of the wheel end torque, the maximum change rate of the speed is calculated, the maximum change rate of the speed is the maximum value of the correction speed change rate, the correction speed change rate is used to correct the corrected vehicle speed to the actual vehicle speed, the vehicle determines the target torque of the drive motor based on the lock speed in the preset mode, and when the preset condition is met, the lock speed is adjusted to obtain the corrected vehicle speed at the correction speed change rate and determines the target torque of the drive motor based on the corrected vehicle speed, until the corrected vehicle speed is less than or equal to the actual vehicle speed.

[0076] Specifically, first, the maximum change rate of the wheel end torque is calculated according to the maximum change rate of the drive shaft torque.

[0077] In one embodiment, the maximum change rate of the wheel end torque is calculated according to the maximum change rate of the drive shaft torque, including: The maximum change rate of the drive shaft torque is multiplied by the transmission efficiency to obtain the maximum change rate of the wheel end torque.

[0078] Specifically, the maximum change rate of the driving shaft torque has been obtained, and the actual torque acts on the wheel end, so the maximum change rate of the driving shaft torque needs to be converted to the maximum change rate of the wheel end torque. This process needs to multiply a transmission efficiency, that is, the maximum change rate of the driving shaft torque x transmission efficiency = the maximum change rate of the wheel end torque. The transmission efficiency is a vehicle parameter and is determined according to the transmission system between the driving shaft and the wheel end. Generally, the transmission efficiency is very close to 1, and in some embodiments, the transmission efficiency can be ignored, and the maximum change rate of the driving shaft torque is taken as the maximum change rate of the wheel end torque.

[0079] Then, the maximum change rate of the speed is calculated according to the maximum change rate of the wheel end torque.

[0080] In one embodiment, the calculation of the maximum change rate of the speed according to the maximum change rate of the wheel end torque comprises: The maximum change rate of the wheel end torque is divided by the tire radius to obtain the maximum change rate of the wheel end torsional force. The maximum change rate of the wheel end torsional force is divided by the vehicle mass to obtain the maximum change rate of the speed.

[0081] Specifically, the obtained maximum change rate of the wheel end torque is converted to the maximum change rate of the wheel end torsional force. The formula is: The maximum change rate of the wheel end torsional force = the maximum change rate of the wheel end torque ÷ the tire radius, wherein the tire radius is also the dynamic radius.

[0082] Since force = mass x acceleration, the maximum value of the acceleration is obtained by dividing the maximum value of the wheel end torsional force by the vehicle mass. The acceleration is the change rate of the corrected speed, so the maximum value of the acceleration obtained at this time is the maximum change rate of the speed.

[0083] Therefore, since the maximum change rate of the wheel end torsional force obtained is the maximum change amount of the wheel end torsional force per unit time, the maximum change rate of the wheel end torsional force is divided by the vehicle mass to obtain the maximum change rate of the speed, that is, the maximum change amount of the speed per unit time.

[0084] The embodiment ensures that the acceleration change of the motor is less than a specific value within a specific period by designing the maximum change rate of the speed when the corrected speed is corrected to the actual speed based on the driving impact boundary value concept, effectively avoids driving impact and gear tooth phenomenon, and improves driving comfort. At the same time, the method prevents the accelerator from being opened too early, makes the vehicle response meet the driving habits of customers, realizes the maximum possible correction rate under the premise of ensuring no driving impact, perfects the torque persistence control function, and improves the overall driving experience of customers. Through reasonable design of the maximum change rate of the speed, the driving impact and gear tooth phenomenon caused by too fast correction rate and the poor accelerator operability and early opening of the accelerator caused by too slow correction rate are successfully solved, and the best balance between the two is achieved.

[0085] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the application.

[0086] As Figure 5 The hardware structure of an electronic device is shown in the figure, which comprises: at least one processor 501; and a memory 502 connected in communication with the at least one processor 501; wherein The memory 502 stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the electric vehicle torque control vehicle speed correction rate maximum value determination method as described above.

[0087] Figure 5 The processor 501 is taken as an example in the figure.

[0088] The electronic device can further comprise an input device 503 and a display device 504.

[0089] The processor 501, the memory 502, the input device 503 and the display device 504 can be connected through a bus or other means, and the figure is taken as an example of connection through a bus.

[0090] The memory 502 is a non-volatile computer readable storage medium, which can be used to store non-volatile software programs, non-volatile computer executable programs and modules, such as the program instructions / modules corresponding to the electric vehicle torque control vehicle speed correction rate maximum value determination method in the embodiments of the present application, for example, Figure 1 , Figure 2 The method flow is shown in the figure. The processor 501 executes various functional applications and data processing by running the non-volatile software programs, instructions and modules stored in the memory 502, that is, the electric vehicle torque control vehicle speed correction rate maximum value determination method in the above embodiments is realized.

[0091] The memory 502 can include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required by a function; the data storage area can store data created according to the use of the electric vehicle torque control speed correction rate maximum value determination method, etc. In addition, the memory 502 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state memory device. In some embodiments, the memory 502 can optionally include a memory disposed remotely with respect to the processor 501, which can be connected to the device executing the electric vehicle torque control speed correction rate maximum value determination method through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0092] The input device 503 can receive an input user click, and generate a signal input related to user settings and function control of the electric vehicle torque control speed correction rate maximum value determination method. The display device 504 can include a display screen and the like display equipment.

[0093] When the one or more modules are stored in the memory 502, when executed by the one or more processors 501, the electric vehicle torque control speed correction rate maximum value determination method in any of the above method embodiments is executed.

[0094] The present application determines a suitable rate maximum change rate based on the motor acceleration maximum change value and in combination with vehicle parameters such as tooth gap, effectively avoids driving impact and tooth clashing phenomenon, improves driving comfort, realizes the maximum possible correction rate under the premise of ensuring no driving impact, perfects the torque persistence control function, and improves the overall driving experience of the driver. The rate maximum change rate is determined by a scientific calculation method, so that the control process is more accurate and reliable.

[0095] An embodiment of the present application provides a storage medium, which stores computer instructions, when a computer executes the computer instructions, all steps of the electric vehicle torque control speed correction rate maximum value determination method as described above are executed.

[0096] In the context of the present disclosure, the storage medium can be a tangible medium which can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The storage medium can be a machine-readable signal medium or a machine-readable storage medium. Alternatively, the storage medium can be a non-transitory computer-readable storage medium, for example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a compact disc read-only memory (CD-ROM), a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0097] An embodiment of the present application provides a computer program product comprising computer programs / instructions which, when executed by a processor, implement the electric vehicle torque control vehicle speed correction rate maximum value determination method as described above.

[0098] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method for determining the maximum value of the vehicle speed correction rate for torque control in an electric vehicle, characterized in that, include: Obtain the maximum change in motor acceleration within a predetermined preset period; Based on the maximum change in motor acceleration and vehicle parameters, calculate the maximum change in drive-end torque and torsion angle of the vehicle. Calculate the maximum rate of change of drive shaft torque based on the maximum change value of drive end torque, torsion angle and tooth backlash; Based on the maximum change rate of the drive shaft torque, the maximum change rate of the speed is calculated. The maximum change rate of the speed is the maximum value of the correction rate of the speed. The correction rate of the speed is used to correct the vehicle speed to the actual vehicle speed. In a preset mode, the target torque of the drive motor is determined based on the locked vehicle speed. When preset conditions are met, the locked vehicle speed is adjusted by the correction rate of the speed to obtain the corrected vehicle speed, and the target torque of the drive motor is determined based on the corrected vehicle speed, until the corrected vehicle speed is less than or equal to the actual vehicle speed.

2. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 1, characterized in that, The step of calculating the maximum change in drive-end torque and torsion angle of the vehicle based on the maximum change in motor acceleration and vehicle parameters includes: Calculate the maximum change in drive-end torque based on the maximum change in motor acceleration, vehicle mass, and drive shaft radius; The torsion angle is calculated based on the maximum change in torque at the drive end and the torsional stiffness.

3. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 1, characterized in that, The calculation of the maximum rate of change of drive shaft torque based on the maximum change in drive end torque, torsion angle, and backlash includes: Based on the maximum change in the driving end torque and the torsion angle, the maximum work done by the driving end is calculated; Calculate the maximum force on the drive shaft based on the maximum work done at the drive end and the tooth clearance. Multiply the maximum force on the drive shaft by the radius of the drive shaft to obtain the maximum change in the torque of the drive shaft; The maximum change in drive shaft torque is divided by the duration of a preset period to obtain the maximum rate of change in drive shaft torque.

4. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 3, characterized in that, The calculation of the maximum force on the drive shaft based on the maximum work done at the drive end and the backlash includes: The maximum force on the drive shaft is calculated by dividing the maximum work done at the drive end by the tooth clearance.

5. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 1, characterized in that, The calculation of the maximum rate of change based on the maximum rate of change of drive shaft torque includes: Calculate the maximum rate of change of wheel-end torque based on the maximum rate of change of drive shaft torque; The maximum rate of change of speed is calculated based on the maximum rate of change of the wheel end torque.

6. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 5, characterized in that, The calculation of the maximum change rate of wheel-end torque based on the maximum change rate of the drive shaft torque includes: Multiplying the maximum rate of change of the drive shaft torque by the transmission efficiency yields the maximum rate of change of the wheel end torque.

7. The method for determining the maximum value of the vehicle speed correction rate for torque control in electric vehicles according to claim 5, characterized in that, The calculation of the maximum rate of change of speed based on the maximum rate of change of wheel end torque includes: Divide the maximum rate of change of wheel end torque by the tire radius to obtain the maximum rate of change of wheel end torsional force. Divide the maximum rate of change of the wheel-end torsional force by the total vehicle mass to obtain the maximum rate of change of the speed.

8. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to at least one of the processors; wherein, The memory stores instructions executable by at least one of the processors, which enable the at least one processor to perform the method for determining the maximum value of the electric vehicle torque control speed correction rate as described in any one of claims 1 to 7.

9. A storage medium, characterized in that, The storage medium stores computer instructions, which, when executed by the computer, are used to perform all the steps of the method for determining the maximum value of the electric vehicle torque control speed correction rate as described in any one of claims 1 to 7.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the method for determining the maximum value of the vehicle speed correction rate for electric vehicle torque control as described in any one of claims 1 to 7.

Images