Self-adaptive control method for pre-torque of vehicle electric driving system

Abstract

The invention discloses a self-adaptive control method for pre-torque of an electric driving system for a vehicle, which comprises the following steps of: monitoring the fluctuation rotating speed of a motor and the rotating angle of a motor rotor under a static gear shifting working condition, and carrying out self-adaptive adjustment on a pre-torque slope and a pre-torque value according to the fluctuation rotating speed of the motor and the rotating angle of the motor rotor. On the basis of the basic theory of the electric drive system, subjective and objective evaluation methods are integrated, the pre-torque value and the pre-torque slope are subjected to self-adaptive change by recognizing the gear engaging working condition and triggering the fluctuation rotating speed of the motor, automatic recognition is carried out in the gear engaging process of a driver every time, adjustment is carried out in the gear engaging process of the next time, and the situation cannot be sensed by the driver of the whole vehicle; and non-inductive self-adaption is realized, and the stability of full-life-cycle operation of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle electric drive systems, and in particular to an adaptive control method for pre-torque of a vehicle electric drive system. Background Art

[0002] The electric drive system for vehicles is generally integrated with transmission components such as spline teeth, reducer teeth, and differential teeth. The resulting transmission gap not only provides lubrication space for the operation of mechanical components, but also causes impact and vibration problems in various components of the system. In addition, the electromagnetic torque has a fast response time, it is difficult to accurately control small torques, permanent magnet demagnetization, transmission component wear and other factors will also aggravate the impact and vibration caused by the switching of positive and negative torques in the electric drive system, reducing the quality of vehicle use and driving comfort. Pre-torque control is the consensus of the current academic and industrial circles to optimize this problem, but there are problems such as the control parameters are difficult to cover the differences in samples, the calibration work is cumbersome, and the control parameters cannot adapt to the entire life cycle of the system.

[0003] The current pre-torque control parameters are mainly the pre-torque size and the torque step size of each cycle of the pre-torque command, hereinafter referred to as the pre-torque value and the pre-torque slope. The pre-torque slope directly determines the time required for the execution of the pre-torque control. If the slope is too small, the pre-torque time will be too long, affecting the vehicle's gear start, and in severe cases, it will cause the vehicle to start shaking; if the slope is too large, it will cause system shock and gear shaking. Due to sample differences, the same pre-torque value will not result in the same angle of rotation of the motor rotor, and its value will fall within a certain range according to the design and manufacturing tolerances. As the system wears during operation, the rotation angle of the motor rotor will become larger and larger. At this time, only a smaller pre-torque value is needed to eliminate the transmission gap; however, the pre-torque value and pre-torque slope in the prior art are often fixed, which cannot adapt well to the operating conditions of different electric drive systems, thereby reducing the stability and comfort of the system operation. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide an adaptive control method for pre-torque of a vehicle electric drive system that can adaptively change the pre-torque value and the pre-torque slope, thereby improving the system operation stability and comfort.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses an adaptive control method for pre-torque of an electric drive system for a vehicle. Under a static shifting condition, the motor fluctuation speed and the motor rotor rotation angle are monitored, and the pre-torque slope and the pre-torque value are adaptively adjusted according to the motor fluctuation speed and the motor rotor rotation angle.

[0007] Preferably, the method comprises the following steps:

[0008] Step 1) identifying the current gear shifting condition, and executing step 2) when the current gear shifting condition is identified as a static gear shifting condition;

[0009] Step 2) monitor whether the maximum value of the motor fluctuation speed within the set time is greater than the speed trigger threshold, if so, execute step 3), if not, reset the timer and return to execute step 1);

[0010] Step 3) reducing the pre-torque slope based on the initial pre-torque slope, and adding 1 to the counter;

[0011] Step 4) monitoring whether the maximum value of the motor rotor rotation angle within the set time is greater than the maximum rotation angle trigger threshold, if so, preparing to reduce the pre-torque value according to the set method, and then executing step 6), if not, executing step 5);

[0012] Step 5) further determines whether the maximum value of the motor rotor rotation angle within the set time is less than the minimum rotation angle trigger threshold value, if so, prepare to increase the pre-torque value according to the set method and then execute step 6), if not, return to execute step 1);

[0013] Step 6) determining whether the counter is currently an even number and whether the preparation for increasing or decreasing the pre-torque value has been completed, if so, executing step 6), if not, returning to executing step 1);

[0014] Step 7) increasing or decreasing the torque value according to step 4) or step 5), and then returning to step 1);

[0015] Step 8) determines whether the current counter value in step 3) is greater than the counter threshold. If so, the process ends after reporting a fault warning. If not, the process returns to step 1).

[0016] Preferably, the static shifting condition includes switching from a forward gear to a reverse gear and from a reverse gear to a forward gear.

[0017] Preferably, the maximum value S of the motor fluctuation speed within 2t is monitored. D Is it greater than the speed trigger threshold S? S , if S D >S S , then the pre-torque slope K n =0.9K n-1 ; Among them, K n is the pre-torque slope at time n, K n-1 is the pre-torque slope at time n-1, and t is the gear switching time.

[0018] Preferably, the pre-torque value of the forward gear is set to a, and the pre-torque value of the reverse gear is set to b. The method for determining the pre-torque value is: testing the absolute value of the minimum torque that can overcome the system friction and rotational inertia and eliminate the transmission gap of the electric drive system by corresponding gears of multiple electric drive systems.

[0019] Preferably, the speed trigger threshold S S The method for determining is as follows: select multiple electric drive systems, conduct orthogonal experiments on the parts with the largest and smallest radial clearances in the multiple electric drive systems, and perform the minimum slope K between the pre-torque value and the pre-torque. min The maximum fluctuation speed that satisfies the subjective and objective shift comfort evaluation under the load is the speed trigger threshold S S .

[0020] Preferably, the pre-torque performs a minimum slope K min The calculation formula is:

[0021]

[0022] Preferably, the initial slope of the pre-torque is K0, and the method for determining the initial slope of the pre-torque K0 is: when the pre-torque value is constant, the loading time is continuously shortened until the loading reaches the maximum fluctuation speed that does not meet the subjective and objective shift comfort evaluation, and the initial slope of the pre-torque K0 is calculated based on the ratio of the pre-torque value at this time to the loading time.

[0023] Preferably, the maximum trigger threshold of the rotation angle is and minimum trigger threshold of rotation angle The determination method is as follows: the maximum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the maximum rotation angle trigger threshold The minimum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the minimum trigger threshold of the rotation angle.

[0024] Preferably, the maximum value of the motor rotor rotation angle within 2t time is monitored like Then reduce the pre-torque value by 0.1a or 0.1b. Then prepare to increase the pre-torque value by 0.1a or 0.1b.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. Based on the basic theory of electric drive system, the present invention incorporates subjective and objective evaluation methods. By identifying the gear shifting condition and triggering the motor's fluctuating speed, the pre-torque value and the pre-torque slope are adaptively changed. Each time the driver shifts into gear, it is automatically identified and adjusted in the next gear shift. It will not be perceived by the driver of the vehicle, thus realizing senseless adaptation and improving the stability of the system's full life cycle operation.

[0027] 2. The adaptive control method of pre-torque of the electric drive system disclosed in the present invention can optimize the abnormal impact, vibration and noise of the electric drive system caused by partial or overall demagnetization of the motor and wear of transmission mechanisms such as gears, bearings and splines during the entire life cycle, achieve full life cycle coverage of the hardware by the electronic control software, reduce the degradation of the driving performance of the whole vehicle during use, realize fault warning of the performance degradation boundary, and improve user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Attached Figure 1 It is an overall flow chart of the adaptive control method of pre-torque of the vehicle electric drive system of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0030] In this specific embodiment, an adaptive control method for pre-torque of a vehicle electric drive system monitors the motor fluctuation speed and the motor rotor rotation angle under static shift conditions, and adaptively adjusts the pre-torque slope and pre-torque value according to the motor fluctuation speed and the motor rotor rotation angle.

[0031] Below, the control data designed in the adaptive control method of the present invention is first described:

[0032] Pre-torque value: Set the pre-torque value of the forward gear to a, and the pre-torque value of the reverse gear to b. The method for determining the pre-torque value is: test multiple electric drive systems (in actual experiments, no less than 3 electric drive systems need to be tested) and find the absolute value of the minimum torque that can overcome the system friction and rotational inertia and eliminate the transmission gap of the electric drive system at the corresponding gear.

[0033] Speed ​​trigger threshold s S :Select multiple electric drive systems (in actual experiments, no less than 3 electric drive systems need to be tested), and conduct orthogonal experiments on the parts with the largest and smallest radial clearances in multiple electric drive systems. min The maximum fluctuation speed that satisfies the subjective and objective shift comfort evaluation under the load is the speed trigger threshold S S .

[0034] Pre-torque execution minimum slope k min : Its value takes into account the time t (i.e., shifting time) for two consecutive actions: engaging the gear and releasing the brake and lifting the leg. It is usually calculated as twice the median time of an average person. The calculation formula is:

[0035] The initial slope of pre-torque is k0: when the pre-torque value is constant, the loading time is continuously shortened until the loading reaches the maximum fluctuation speed that does not meet the subjective and objective shift comfort evaluation. The initial slope of pre-torque k0 is calculated based on the ratio of the pre-torque value at this time to the loading time.

[0036] Maximum trigger threshold of rotation angle and minimum trigger threshold of rotation angle The maximum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the maximum rotation angle trigger threshold The minimum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the minimum trigger threshold of the rotation angle.

[0037] The adaptive control method for pre-torque of the electric drive system for a vehicle of the present invention is described in detail below. Figure 1 As shown, the method comprises the following steps:

[0038] Step 1) identifies the current gear shifting condition, and executes step 2) when it is identified that the current gear shifting condition is a static gear shifting condition; specifically, 1) identifies whether the current gear shifting condition is a static gear shifting condition based on the change in the gear position command sent by the vehicle controller in the current cycle and the previous cycle. The static gear shifting condition includes switching from the forward gear to the reverse gear (D / R switching) and switching from the reverse gear to the forward gear (R / D switching). The output logic signal is defined as true when the static gear shifting condition is used.

[0039] Step 2) monitors whether the maximum value of the motor fluctuation speed within the set time is greater than the speed trigger threshold. If so, execute step 3). If not, the timer is reset and returns to execute step 1); specifically, monitor the maximum value S of the motor fluctuation speed within 2t. DIs it greater than the speed trigger threshold S? S , if S D >S S , then the pre-torque slope K n =0.9K n＝1 , where K n is the pre-torque slope at time n, K n-1 is the pre-torque slope at time n-1, and t is the gear switching time.

[0040] Step 3) The pre-torque slope is reduced based on the initial pre-torque slope, and the counter is increased by 1, that is, C=C+1, and the initial value of the counter is 0.

[0041] Step 4) monitors whether the maximum value of the motor rotor rotation angle within the set time is greater than the maximum rotation angle trigger threshold. If so, prepare to reduce the pre-torque value according to the set method, and then execute step 6), if not, execute step 5); specifically, monitor the maximum value of the motor rotor rotation angle within 2t time like Then prepare to reduce the pre-torque value by 0.1a or 0.1b.

[0042] Step 5) further determines whether the maximum value of the motor rotor rotation angle within the set time is less than the minimum rotation angle trigger threshold. If so, prepare to increase the pre-torque value according to the set method and then execute step 6). If not, return to execute step 1); specifically, monitor the maximum value of the motor rotor rotation angle within 2t time. like Then prepare to increase the pre-torque value by 0.1a or 0.1b.

[0043] Step 6) determines whether the counter is currently an even number and the preparation for increasing or decreasing the pre-torque value is completed. If so, execute step 6), otherwise return to execute step 1); specifically, if C>0 and C is an even number, the pre-torque value is increased or decreased in steps of 0.1a or 0.1b.

[0044] Step 7) increases or decreases the torque value according to step 4) or step 5), and then returns to step 1).

[0045] Step 8) determines whether the current counter value in step 3) is greater than the counter threshold. If so, the fault warning is reported and the process ends. If not, the process returns to step 1). Specifically, if C=X, X is the minimum value that cannot meet the subjective and objective shift comfort evaluation in the vehicle durability test, and the electric drive system pre-torque control fault is reported. The number of times can be calibrated, which is determined by the pre-torque value, the pre-torque slope, the motor fluctuation speed threshold, etc.

[0046] Compared with the prior art, the present invention integrates subjective and objective evaluation methods on the basis of the basic theory of electric drive system, and adaptively changes the pre-torque value and pre-torque slope by identifying the gear-engaging condition and triggering the motor's fluctuating speed. It automatically identifies each time the driver engages in gear, and adjusts the next time the gear is engaged, which will not be perceived by the driver of the vehicle, thus realizing senseless adaptation and improving the stability of the system's full life cycle operation. Through the adaptive control method of pre-torque of the electric drive system disclosed in the present invention, the abnormal impact, vibration and noise of the system caused by partial or overall demagnetization of the motor and wear of transmission mechanisms such as gears, bearings, and splines in the electric drive system during the full life cycle can be optimized, and the full life cycle coverage of the hardware by the electronic control software can be achieved, the decline of the vehicle's driving performance during use can be reduced, and fault warning of the performance decline boundary can be achieved, thus improving the user experience.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. An adaptive control method for pre-torque of an electric drive system for a vehicle, characterized in that: Under static shifting conditions, the motor fluctuation speed and the motor rotor rotation angle are monitored, and the pre-torque slope and the pre-torque value are adaptively adjusted according to the motor fluctuation speed and the motor rotor rotation angle.

2. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 1, characterized in that: The following steps are involved: Step 1) identifying the current gear shifting condition, and executing step 2) when the current gear shifting condition is identified as a static gear shifting condition; Step 2) monitor whether the maximum value of the motor fluctuation speed within the set time is greater than the speed trigger threshold, if so, execute step 3), if not, reset the timer and return to execute step 1); Step 3) reducing the pre-torque slope based on the initial pre-torque slope, and adding 1 to the counter; Step 4) monitoring whether the maximum value of the motor rotor rotation angle within the set time is greater than the maximum rotation angle trigger threshold, if so, preparing to reduce the pre-torque value according to the set method, and then executing step 6), if not, executing step 5); Step 5) further determines whether the maximum value of the motor rotor rotation angle within the set time is less than the minimum rotation angle trigger threshold value, if so, prepare to increase the pre-torque value according to the set method and then execute step 6), if not, return to execute step 1); Step 6) determining whether the counter is currently an even number and whether the preparation for increasing or decreasing the pre-torque value has been completed, if so, executing step 6), if not, returning to executing step 1); Step 7) increasing or decreasing the torque value according to step 4) or step 5), and then returning to step 1); Step 8) determines whether the current counter value in step 3) is greater than the counter threshold. If so, the process ends after reporting a fault warning. If not, the process returns to step 1).

3. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 2, characterized in that: Static shift conditions include switching from forward gear to reverse gear and from reverse gear to forward gear.

4. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 3, characterized in that: Monitor the maximum value S of the motor fluctuation speed within 2t D Is it greater than the speed trigger threshold S? S , if S D >S S , then the pre-torque slope K n =0.9K n-1 ; Among them, K n is the pre-torque slope at time n, K n-1 is the pre-torque slope at time n-1, and t is the gear switching time.

5. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 4, characterized in that: The pre-torque value of the forward gear is set to a, and the pre-torque value of the reverse gear is set to b. The method for determining the pre-torque value is: testing the absolute value of the minimum torque that can overcome the system friction and rotational inertia and eliminate the transmission clearance of the electric drive system at the corresponding gears of multiple electric drive systems.

6. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 5, characterized in that: Speed ​​trigger threshold S S The method for determining is as follows: select multiple electric drive systems, conduct orthogonal experiments on the parts with the largest and smallest radial clearances in the multiple electric drive systems, and perform the minimum slope K between the pre-torque value and the pre-torque. min The maximum fluctuation speed that satisfies the subjective and objective shift comfort evaluation under the load is the speed trigger threshold S S .

7. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 6, characterized in that: Pre-torque execution minimum slope K min The calculation formula is:

8. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 7, characterized in that: The initial slope of pre-torque is K0. The method for determining the initial slope of pre-torque K0 is as follows: when the pre-torque value is constant, the loading time is continuously shortened until the loading reaches the maximum fluctuation speed that does not meet the subjective and objective shift comfort evaluation. The initial slope of pre-torque K0 is calculated based on the ratio of the pre-torque value at this time to the loading time.

9. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 8, characterized in that: Maximum trigger threshold of rotation angle and minimum trigger threshold of rotation angle The determination method is as follows: the maximum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the maximum rotation angle trigger threshold The minimum rotation angle of the motor rotor obtained under the combined loading of the pre-torque initial slope K0 and the pre-torque value a and the pre-torque value b is the minimum trigger threshold of the rotation angle.

10. The method for adaptively controlling the pre-torque of a vehicle electric drive system according to claim 9, characterized in that: Monitor the maximum value of the motor rotor rotation angle within 2t time like Then reduce the pre-torque value by 0.1a or 0.1b. Then prepare to increase the pre-torque value by 0.1a or 0.1b.

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