Torsional vibration suppression system and method for hybrid electric vehicle

Abstract

According to the torsional vibration suppression system and method for the hybrid electric vehicle, an inherent frequency calculation module calculates the inherent frequency of a transmission system of a torsional vibration damper in different states, and a resonant frequency analysis module determines the excitation frequency according to engine rotating speed and motor rotating speed signals and judges whether resonance control needs to be carried out or not; the resonance control module generates motor additional torque, resonance possibly caused by power source excitation and a transmission system is avoided, the gap observation module estimates the gear meshing gap of the transmission system in the vehicle running process in real time and judges the mode of the gap, and the gap active control module determines motor command torque according to the estimation result of the gap observation module. By means of the method, the problem of transmission system oscillation caused by gaps under the sudden acceleration / deceleration (Tip-in / out) and starting working conditions can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile power transmission system control, and in particular relates to a hybrid electric vehicle torsional vibration suppression system and method. Background Art

[0002] The automobile manufacturing industry is moving towards clean energy. Hybrid vehicles are gradually becoming the mainstream choice in the new energy vehicle market. This type of vehicle has obvious advantages in economy and power performance, however, this has also triggered a series of new problems about driving comfort and safety. The power transmission system of hybrid vehicles is its key component. It uses a power coupling device to integrate the output power of the internal combustion engine and the electric motor to adapt to different driving conditions, thereby achieving efficient vehicle drive, which is crucial to ensure the performance of hybrid vehicles. Therefore, hybrid vehicles face more complex and diverse torque vibration problems. This complexity is mainly caused by two aspects: on the one hand, under unstable operating conditions such as vehicle starting, shifting, braking and mode conversion, it will be affected by multiple excitation factors such as the engine, motor, transmission components and road surface, causing the transmission system to bear huge dynamic loads, making the torque vibration problem more significant, which directly affects the stability, reliability and safety of the transmission system and increases the possibility of accidents. On the other hand, the engine, which is the main power source of the car and the main source of torque vibration, may generate noise and resonance if the transmission system is not designed properly, and in severe cases, it may even cause damage to the shock absorber. Although the newly added motor in the hybrid car improves the response speed, it may also make the power transmission unstable, which has a negative impact on the reliability and durability of the transmission system, and may even cause safety hazards and failures such as broken shafts, broken teeth, and pitting of tooth surfaces. Therefore, it is particularly urgent to solve the problem of torque vibration control in the hybrid car transmission system.

[0003] When the power source excitation frequency of the drive system coincides with the natural frequency of the system, resonance occurs, causing the system vibration to reach maximum, which not only degrades the driving experience but may even endanger the driver's safety. In addition, the clearance in the drive system is also an important cause of torsional vibration. When the vehicle torque crosses the gap area, such as from positive torque to negative torque or vice versa, idling may occur due to the clearance in the drive system components. This torque disturbance or clearance will generate noise, vibration and acoustic harshness, degrading driving performance. Therefore, resonance and drive system clearance are the key factors leading to torsional vibration problems in hybrid vehicle drive systems. Summary of the invention

[0004] The technical problem to be solved by the present invention is: suppressing the torsional vibration of the transmission system caused by resonance and transmission system clearance, and improving the NVH quality of hybrid vehicles. In response to this technical problem, the present invention proposes a hybrid vehicle torsional vibration suppression system and method, which uses a resonant controller to regulate the motor torque to avoid the transmission system resonance caused by the excitation of each power source, and uses an extended Kalman filter observer to estimate the transmission system clearance and divide the mode. In the gap mode, a sliding mode controller is used to adjust the motor torque, and in the contact mode, an adaptive controller is used to adjust the motor torque. The technical solution adopted by the present invention is:

[0005] A hybrid electric vehicle torsional vibration suppression system comprises a natural frequency calculation module, a resonant frequency analysis module, a resonant control module, a clearance angle observation module, a clearance active control module and a hybrid electric vehicle transmission system; the natural frequency calculation module calculates the natural frequency of the transmission system under different states of the torsional vibration damper and outputs it to the resonant frequency analysis module; the resonant frequency analysis module determines the excitation frequency according to the engine speed and the motor speed signal, judges whether resonance control is required in combination with the natural frequency of the transmission system, and transmits the resonant frequency to the resonant control module; the resonant control module determines the additional command torque of the motor according to the resonant frequency and the power source speed to avoid the resonance that may be caused by the power source excitation and the transmission system; the clearance observation module estimates the gear meshing clearance of the transmission system in real time according to the vehicle state information during the operation of the vehicle, judges the mode of the clearance, and transmits the obtained mode signal to the clearance active control module; the clearance active control module uses different controllers to determine the motor command torque according to the mode result of the clearance observation module; the system runs in a computing environment with a multi-core processor, a high-speed cache and a large-capacity random access memory, adopts a real-time operating system to ensure the efficient coordinated operation of each module, and realizes data interaction between modules through a high-speed communication bus.

[0006] Preferably, the input required by the natural frequency calculation module is the engine torque. According to the torsional vibration damper stiffness characteristic curve, a mathematical interpolation algorithm is used to obtain the torsional vibration damper stiffness values ​​corresponding to different engine torques. The system natural frequency at different torsional vibration damper stiffnesses is calculated by solving the undamped free vibration equation, and the system natural frequency is output.

[0007] Preferably, the resonant frequency analysis module determines the current excitation frequency of each power source based on the engine and motor speed signals, and determines whether to perform resonance control by comparing with the natural frequency of the transmission system. The natural frequency is obtained from the natural frequency calculation module. If resonance control is required, the natural frequency close to the excitation frequency is output as the resonant frequency.

[0008] Preferably, the resonance control module uses a dual-T network resonance controller to determine the additional command torque of the motor according to the resonance frequency and the power source speed, and the outputs of multiple dual-T resonance controllers are used as the output of the resonance control module, including:

[0009] The engine resonance frequency and the engine speed are input into the double-T network resonance controller 1 to generate an additional torque on the engine side, and the additional torque on the engine side is converted into an additional command torque 1 on the motor 1 side according to system dynamics;

[0010] The motor 1 resonant frequency and the motor 1 speed are input into the double-T network resonant controller 2 to generate the motor 1 side additional command torque 2;

[0011] The additional command torque 1 on the motor 1 side is summed with the additional command torque 2 on the motor 1 side to obtain the additional command torque on the motor 1 side;

[0012] The resonant frequency of the motor 2 and the rotational speed of the motor 2 are input into the double-T network resonant controller 3 to generate an additional command torque on the motor 2 side.

[0013] Preferably, the clearance observation module uses an extended Kalman filter observer to estimate the gear clearance in the transmission system in real time, and the input of the clearance angle observation module is the speed and torque of the gear component, and the clearance mode and contact mode are divided as output according to the estimation result.

[0014] Preferably, the input of the gap active control module is the result of the gap observation module, and active control is performed for each mode based on the result, and the output of the gap active control module is the output of each mode controller; when in the gap mode, a sliding mode variable structure controller is used to calculate the motor command torque with the goal of minimizing the speed difference at both ends of the gear. The input of the sliding mode variable structure controller is the speed at both ends of the gear, and the output is the motor command torque; when in the contact mode, an adaptive controller is used to calculate the motor command torque with the goal of preventing the torsional vibration of the transmission system caused by load changes and starting. The input of the adaptive controller is the reference model tracking error, and the output is the motor command torque.

[0015] The torsional vibration suppression method proposed in the technical solution of the present invention comprises the following steps:

[0016] (1) Determine the type and operating mode of the hybrid vehicle, establish a concentrated mass model of the transmission system, and obtain the undamped free vibration equations of the vehicle under different modes based on the concentrated mass model of the transmission system;

[0017] (2) The natural frequency calculation module obtains the torsional vibration damper stiffness value corresponding to different engine torques according to the engine torque and the torsional vibration damper stiffness characteristic curve using a mathematical interpolation algorithm, calculates the system natural frequency at different torsional vibration damper stiffnesses by solving the undamped free vibration equation, and outputs the system natural frequency.

[0018] (3) The resonance frequency analysis module determines the excitation frequency of each power source according to the engine and motor speed signals, and compares it with the natural frequency of the transmission system. If the excitation frequency is close to the natural frequency, it is determined that resonance control is required, and the natural frequency close to the excitation frequency is transmitted to the resonance control module as the resonance frequency;

[0019] (4) The resonance control module takes the resonance frequency and the power source speed as input, and uses a dual-T network resonance controller to generate additional command torques for motors 1 and 2. The engine resonance frequency and the engine speed are input into the dual-T network resonance controller 1 to generate an additional torque on the engine side. According to system dynamics, the additional torque on the engine side is converted into an additional command torque 1 on the motor 1 side; the motor 1 resonance frequency and the motor 1 speed are input into the dual-T network resonance controller 2 to generate an additional command torque 2 on the motor 1 side; the additional command torque 1 on the motor 1 side is summed with the additional command torque 2 on the motor 1 side to obtain an additional command torque on the motor 1 side; the motor 2 resonance frequency and the motor 2 speed are input into the dual-T network resonance controller 3 to generate an additional command torque on the motor 2 side;

[0020] The transfer function of the double-T network resonant controller can be expressed as:

[0021]

[0022] Where s is the complex variable used in Laplace transform, ω n is the resonant frequency, a and b are the damping ratio coefficients;

[0023] (5) Establish a backlash dynamics model. The backlash angle observation module uses an extended Kalman filter observer based on the gear component speed, torque and backlash dynamics model to estimate the gear backlash in the transmission system in real time, and divides the backlash mode and contact mode according to the estimation results;

[0024] (6) The gap active control module receives the results of the gap observation module and performs active control for each mode based on the results.

[0025] The gap mode aims to minimize the speed difference between the components at both ends of the gear. The speed difference between the two ends of the gear is used as the input of the sliding mode variable structure controller to determine the motor command torque. The sliding mode surface and the sliding mode control law can be recorded as:

[0026] s(t)=ω i -ω j

[0027] u h =-k h ·sgn(s(t))-α|s(t)| β

[0028] Among them, s(t) is the sliding surface, u h is the sliding mode control law, sgn() is the sign function, ω i is the driving wheel speed, ω j is the speed of the passive wheel, k h is the control gain, α and β are sliding mode design parameters;

[0029] The contact mode aims to prevent the torsional vibration of the transmission system caused by load changes and starting. A reference model of the transmission system is established, and the tracking error of the reference model is used as the input of the adaptive controller to determine the motor command torque. The adaptive control law can be written as:

[0030]

[0031] Among them, u z is the adaptive control law, k z is the adaptive control gain, e is the tracking error, is the parameter estimation value, f(x) is the nonlinear function of the system;

[0032] (7) The additional command torque on the motor side in step (4), the motor command torque in step (6) and the original command torque are summed to obtain the total motor torque, which is output to the transmission system to suppress the torsional vibration of the transmission system.

[0033] Compared with the prior art, the beneficial effects achieved by the present invention include:

[0034] 1) The present invention provides a torsional vibration suppression system and a torsional vibration suppression method for a hybrid vehicle. The natural frequency calculation module can calculate the natural frequency of a variable structure transmission system under different conditions. The resonant frequency analysis module determines whether the transmission system resonance is induced. The resonant control module generates an additional motor command torque to offset the excitation that is about to induce resonance. The combination of the natural frequency calculation module, the resonant frequency analysis module and the resonant control module can effectively suppress the transmission system coupling vibration caused by the engine and motor excitation. The clearance angle observation module can determine the clearance mode of the vehicle in real time during driving. The clearance active control module regulates the motor torque according to different clearance modes. The clearance angle observation module and the clearance active control module can effectively solve the transmission system oscillation caused by the clearance under sudden acceleration / deceleration (Tip-in / out) and starting conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a schematic diagram of a hybrid vehicle vibration suppression system;

[0036] Figure 2 It is a structural diagram of a power split hybrid vehicle transmission system based on the integration of four clutches;

[0037] Figure 3 It is the control flow chart of the torsional vibration suppression system of the hybrid vehicle;

[0038] Figure 4 It is a concentrated mass model of the power-split hybrid vehicle driveline;

[0039] Figure 5 It is a pure torsion model of the planetary gear;

[0040] Figure 6 is the characteristic diagram of the resonant controller;

[0041] Figure 7 It is the time domain waveform of the output shaft speed with and without resonance control;

[0042] Figure 8 This is the speed time domain waveform diagram when the output shaft is actively controlled with or without backlash under Tip-in working condition;

[0043] Fig. 9 It is the speed time domain waveform diagram when the output shaft is actively controlled with or without backlash under starting conditions;

[0044] Figure 2 Middle: S1-front planetary row sun gear C1-front planetary row planet carrier R1-front planetary row ring gear S2-rear planetary row sun gear C2-rear planetary row planet carrier R2-rear planetary row ring gear CR1, CR2, CB1, CB2-four clutches

[0045] Figure 5 Middle: Sun-Sun gear Carrier-Planet carrier Planet-Planet gear Ring-Gear ring k sp -Average meshing stiffness k between sun gear and planet gear rp -Average meshing stiffness between the ring gear and the planetary gear

[0046] Figure 6 Middle: B T -Bandwidth D T -depth DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] Figure 1The present invention is a schematic diagram of the structure of a hybrid vehicle torsional vibration suppression system to be adopted in an embodiment of the present invention. The system includes a natural frequency calculation module, a resonant frequency analysis module, a resonant control module, a gap angle observation module, a gap active control module and a hybrid vehicle transmission system; the natural frequency calculation module calculates the natural frequency of the transmission system under different states of the torsional damper and outputs it to the resonant frequency analysis module; the resonant frequency analysis module determines the excitation frequency according to the engine speed and the motor speed signal, determines whether resonance control is required in combination with the natural frequency of the transmission system, and transmits the resonant frequency to the resonant control module; the resonant control module determines the additional command torque of the motor according to the resonant frequency and the power source speed to avoid resonance that may be caused by the power source excitation and the transmission system; the gap observation module estimates the gear meshing clearance of the transmission system in real time during the operation of the vehicle according to the vehicle state information, determines the mode of the gap, and transmits the obtained mode signal to the gap active control module; the gap active control module uses different controllers to determine the motor command torque according to the mode result of the gap observation module; the system runs in a computing environment with a multi-core processor, a high-speed cache and a large-capacity random access memory, adopts a real-time operating system to ensure the efficient coordinated operation of each module, and realizes data interaction between modules through a high-speed communication bus.

[0049] The system runs in a computing environment with a multi-core processor, a high-speed cache and a large-capacity random access memory, adopts a real-time operating system to ensure the efficient and coordinated operation of each module, and realizes data interaction between modules through a high-speed communication bus.

[0050] To further illustrate the torsional vibration suppression method proposed in the embodiment of the present invention, a power split hybrid vehicle with four integrated clutches is selected as a research object. The schematic diagram of its transmission system is shown in FIG. Figure 2 As shown in the figure, the power coupling mechanism of the power split hybrid vehicle consists of an engine, motor MG1 and motor MG2, four clutches (CR1, CR2, CB1, CB2) and two sets of planetary gears. The engine is connected to the ring gear R1 of the front planetary gear, the motor MG1 is connected to the sun gear S1 of the front planetary gear, and the motor MG2 is connected to the sun gear S2 of the rear planetary gear. The control flow of the torsional vibration suppression system used is as follows: Figure 3 shown.

[0051] The torsional vibration suppression method proposed in the technical solution of the present invention comprises the following steps:

[0052] (1) The type of hybrid vehicle is determined to be a series-connected type with a dual planetary gear structure integrating four clutches. The working mode is determined according to the combination of engagement and disengagement of different clutches. The concentrated mass model of the transmission system is established as follows: Figure 4 As shown, the planetary gear coupling mechanism is a pure torsion model as shown in Figure 5As shown, the engine, motor 1, motor 2, various components in the planetary gear, reducer / differential, tire and vehicle are simplified to rotational inertia, the torsional vibration damper, motor output shaft, fully combined clutch, output shaft, half shaft, tire elasticity are simplified to equivalent torsional vibration springs with stiffness and damping, and the meshing stiffness of the planetary gear pair adopts the average meshing stiffness k sp , k rp Based on the concentrated mass model of the transmission system, the undamped free vibration equations in different modes are established.

[0053] (2) In the process of implementing the natural frequency calculation module, the instantaneous torque data of the engine is collected through the torque sensor; based on the torque value, the torsional vibration damper stiffness characteristic curve that has been pre-constructed and stored is referred to, and a mathematical interpolation algorithm is used to perform a table lookup operation to solve the torsional vibration damper stiffness value corresponding to the current engine torque; after obtaining the stiffness value, it is substituted into the corresponding position in the stiffness matrix constructed by the undamped free vibration equation, and the vibration equation is solved with the help of a numerical analysis method to obtain the natural frequency of the system, and the calculated natural frequency is used as the output result.

[0054] (3) In the resonant frequency analysis module, the speed signals of the engine and the motor are collected through the speed sensor, and the excitation frequency of each power source is calculated based on the speed signal; the relationship between the excitation frequency and the speed of the engine and the motor can be expressed as:

[0055]

[0056] Among them, f e is the engine excitation frequency, f mg is the motor excitation frequency, a e is the engine excitation order, a mg is the motor excitation order, n e is the engine speed (r / min), n mg is the motor speed (r / min), p is the motor stage number;

[0057] Subsequently, the calculated excitation frequency is compared and analyzed with the natural frequency of the transmission system. If the excitation frequency is close to the natural frequency, that is, it is in a critical state of resonance, the module will determine that the system needs to be resonantly controlled, and the resonant frequency analysis module will transmit the natural frequency data close to the excitation frequency as the resonant frequency to the resonance control module.

[0058] (4) The resonant control module takes the resonant frequency and the power source speed as input and uses multiple dual-T network resonant controllers to generate additional torque for motor 1 and motor 2. The characteristic diagram of the dual-T network resonant controller is shown in the figure below. Figure 6 As shown;

[0059] The transfer function of the double-T network resonant controller can be expressed as:

[0060]

[0061] Where s is the complex variable used in Laplace transform, ω n is the resonant frequency, a and b are the damping ratio coefficients;

[0062] The engine resonant frequency and engine speed are input into the double T-type network resonant controller to generate the engine side additional torque T ep According to the dynamics of the planetary gear train, the additional torque on the engine side is converted into the additional torque on the motor 1 side 1T mg1p1 ;

[0063]

[0064] Among them, K1 is the characteristic parameter of the front planetary gear;

[0065] The motor 1 resonant frequency and the motor 1 speed are input into the double T-type network resonant controller to generate the additional torque 2T on the motor 1 side. mg1p2 ;

[0066] The additional command torque 1 on the motor 1 side and the additional command torque 2 on the motor 1 side are summed to obtain the additional command torque T on the motor 1 side. mg1p ;

[0067] The motor 2 resonant frequency and the motor 2 speed are input into the double T-type network resonant controller to generate the additional torque T on the motor 2 side. mg2p ;

[0068] Figure 7 In the hybrid mode, when the engine excitation frequency is close to the natural frequency of the transmission system and resonance is caused, the time domain waveform of the output shaft speed with and without resonance control is shown. It can be clearly seen that after adding the resonance control strategy proposed in the present invention, the amplitude of the periodic fluctuation of the speed of the output shaft of the transmission system is significantly reduced, indicating the correctness of the idea of ​​torsional vibration suppression through motor torque compensation, and at the same time indicating that the resonance control strategy proposed in the present invention can suppress the torsional vibration of the transmission system.

[0069] (5) Establish the tooth clearance dynamics model, which can be expressed as

[0070]

[0071] Among them, θ b is the backlash value, θ d is the angular displacement of the axis, is θ b The derivative value of is θ d The derivative value, α bis half of the maximum value of the backlash, k is the stiffness value of the shaft connected to the gear, and c is the damping value of the shaft connected to the gear;

[0072] The clearance observation module collects the speed data of the planetary gear components through high-precision speed sensors installed on each component of the planetary gear. Based on the backlash dynamics model and the collected speed data, an extended Kalman filter observer is constructed, with the speed and input / output torque of the planetary gear components as the state variables of the system, and the gear clearance is the state quantity to be estimated. The nonlinear state equation and observation equation are established. The observer uses the speed data at the current moment and the state estimate at the previous moment to perform iterative calculations to obtain the gear clearance estimate at the current moment and the corresponding covariance matrix;

[0073] According to the estimated gear clearance value, the working state of the transmission system is divided into clearance mode and contact mode. th When the gear clearance is less than or equal to the threshold, the system is in contact mode.

[0074] (6) The clearance active control module receives the results of the clearance observation module and performs active control for each mode. The clearance mode aims to minimize the speed difference of the components on both sides of the gear. The speed difference on both sides of the gear is used as the input of the sliding mode variable structure controller to determine the motor command torque. The sliding mode surface and the sliding mode control law can be expressed as:

[0075] s(t)=ω i -ω j

[0076] u h =-k h ·sgn(s(t))-α|s(t)| β

[0077] Among them, s(t) is the sliding surface, u h is the sliding mode control law, sgn() is the sign function, ω i is the driving wheel speed, ω j is the speed of the passive wheel, k h is the control gain, α and β are sliding mode design parameters;

[0078] Figure 8 When the transmission system is in gap mode under Tip-in conditions, the speed time domain waveform of the output shaft with and without active gap control is shown. It can be clearly seen that after adding the sliding mode variable structure control proposed in the present invention, the amplitude of the periodic fluctuation of the speed of the output shaft of the transmission system is significantly reduced, indicating that the sliding mode variable structure control proposed in the present invention can suppress the torsional vibration of the transmission system.

[0079] The contact mode aims to prevent the torsional vibration of the transmission system caused by load changes and starting. The tracking error of the reference model is used as the input of the adaptive controller to determine the motor command torque. The adaptive control law can be written as:

[0080]

[0081] Among them, u z is the adaptive control law, k z is the adaptive control gain, e is the tracking error, is the parameter estimation value, f(x) is the nonlinear function of the system;

[0082] Fig. 9 The time domain waveform diagram of the speed of the output shaft with and without active clearance control when the transmission system is in contact mode under starting conditions. It can be clearly seen that after adding the adaptive control proposed in the present invention, the amplitude of the periodic fluctuation of the speed of the output shaft of the transmission system is significantly reduced, indicating that the adaptive control proposed in the present invention can suppress the torsional vibration of the transmission system.

[0083] (7) The motor side additional torque in step (4), the motor command torque in step (6) and the original command torque are summed to obtain the total motor torque, which is output to the transmission system to suppress the torsional vibration of the transmission system.

Claims

1. A hybrid electric vehicle torsional vibration suppression system, characterized in that: The system includes a natural frequency calculation module, a resonant frequency analysis module, a resonant control module, a clearance angle observation module, a clearance active control module and a hybrid vehicle transmission system; the natural frequency calculation module calculates the natural frequency of the transmission system under different states of the torsional damper and outputs it to the resonant frequency analysis module; the resonant frequency analysis module determines the excitation frequency according to the engine speed and the motor speed signal, judges whether resonance control is required in combination with the natural frequency of the transmission system, and transmits the resonant frequency to the resonant control module; the resonant control module determines the additional command torque of the motor according to the resonant frequency and the power source speed to avoid resonance that may be caused by the power source excitation and the transmission system; the clearance observation module estimates the gear meshing clearance of the transmission system in real time during the operation of the vehicle according to the vehicle state information, judges the mode of the clearance, and transmits the obtained mode signal to the clearance active control module; the clearance active control module uses different controllers to determine the motor command torque according to the mode result of the clearance observation module.

2. A hybrid vehicle torsional vibration suppression system according to claim 1, characterized in that: The input required by the natural frequency calculation module is the engine torque. According to the torsional vibration damper stiffness characteristic curve, a mathematical interpolation algorithm is used to obtain the torsional vibration damper stiffness values ​​corresponding to different engine torques. The system natural frequency at different torsional vibration damper stiffnesses is calculated by solving the undamped free vibration equation, and the system natural frequency is output.

3. A hybrid vehicle torsional vibration suppression system according to claim 1, characterized in that: The resonant frequency analysis module determines the current excitation frequency of each power source according to the engine and motor speed signals, and determines whether to perform resonance control by comparing with the natural frequency of the transmission system. The natural frequency is obtained from the natural frequency calculation module. If resonance control is required, the natural frequency close to the excitation frequency is output as the resonant frequency.

4. A hybrid vehicle torsional vibration suppression system according to claim 1, characterized in that: The resonance control module uses a dual-T network resonance controller to determine the additional command torque of the motor according to the resonance frequency and the power source speed. The outputs of multiple dual-T resonance controllers are used as the output of the resonance control module, including: The engine resonance frequency and the engine speed are input into the double-T network resonance controller 1 to generate an additional torque on the engine side, and the additional torque on the engine side is converted into an additional command torque 1 on the motor 1 side according to system dynamics; The motor 1 resonant frequency and the motor 1 speed are input into the double-T network resonant controller 2 to generate the motor 1 side additional command torque 2; The additional command torque 1 on the motor 1 side is summed with the additional command torque 2 on the motor 1 side to obtain the additional command torque on the motor 1 side; The resonant frequency of the motor 2 and the rotational speed of the motor 2 are input into the double-T network resonant controller 3 to generate an additional command torque on the motor 2 side.

5. The hybrid vehicle torsional vibration suppression system according to claim 1, characterized in that: The gap observation module uses an extended Kalman filter observer to estimate the gear gap in the transmission system in real time. The input of the gap angle observation module is the speed and torque of the gear component, and the gap mode and contact mode are divided as output according to the estimation result.

6. A hybrid vehicle torsional vibration suppression system according to claim 1, characterized in that: The input of the gap active control module is the result of the gap observation module, and active control is performed on each mode based on the result. The output of the gap active control module is the output of each mode controller; When in the gap mode, a sliding mode variable structure controller is used to calculate the motor command torque with the goal of minimizing the speed difference between the two ends of the gear. The input of the sliding mode variable structure controller is the speed at both ends of the gear, and the output is the motor command torque. When in the contact mode, an adaptive controller is used to calculate the motor command torque with the goal of preventing the torsional vibration of the transmission system caused by load changes and starting. The input of the adaptive controller is the reference model tracking error, and the output is the motor command torque.

7. A method for suppressing torsional vibration of a hybrid vehicle torsional vibration suppression system according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Determine the type and operating mode of the hybrid vehicle, establish a concentrated mass model of the transmission system, and obtain the undamped free vibration equations of the vehicle under different modes based on the concentrated mass model of the transmission system; (2) The natural frequency calculation module obtains the torsional vibration damper stiffness value corresponding to different engine torques according to the engine torque and the torsional vibration damper stiffness characteristic curve by using a mathematical interpolation algorithm, calculates the system natural frequency at different torsional vibration damper stiffnesses by solving the undamped free vibration equation, and outputs the system natural frequency; (3) The resonance frequency analysis module determines the excitation frequency of each power source according to the engine and motor speed signals, and compares it with the natural frequency of the transmission system. If the excitation frequency is close to the natural frequency, it is determined that resonance control is required, and the natural frequency close to the excitation frequency is transmitted to the resonance control module as the resonance frequency; (4) The resonance control module takes the resonance frequency and the power source speed as input, and uses a dual-T network resonance controller to generate additional command torques for motors 1 and 2. The engine resonance frequency and the engine speed are input into the dual-T network resonance controller 1 to generate an additional torque on the engine side. According to system dynamics, the additional torque on the engine side is converted into an additional command torque 1 on the motor 1 side; the motor 1 resonance frequency and the motor 1 speed are input into the dual-T network resonance controller 2 to generate an additional command torque 2 on the motor 1 side; the additional command torque 1 on the motor 1 side is summed with the additional command torque 2 on the motor 1 side to obtain an additional command torque on the motor 1 side; the motor 2 resonance frequency and the motor 2 speed are input into the dual-T network resonance controller 3 to generate an additional command torque on the motor 2 side; The transfer function of the double-T network resonant controller can be expressed as: Where s is the complex variable used in Laplace transform, ω n is the resonant frequency, a and b are the damping ratio coefficients; (5) Establish a backlash dynamics model. The backlash angle observation module uses an extended Kalman filter observer based on the gear component speed, torque and backlash dynamics model to estimate the gear backlash in the transmission system in real time, and divides the backlash mode and contact mode according to the estimation results; (6) The gap active control module receives the results of the gap observation module and performs active control for each mode based on the results. The gap mode aims to minimize the speed difference between the components at both ends of the gear. The speed difference between the two ends of the gear is used as the input of the sliding mode variable structure controller to determine the motor command torque. The sliding mode surface and the sliding mode control law can be recorded as: s(t)=ω i -oh j u h =-k h ·sgn(s(t))-α|s(t)| β Among them, s(t) is the sliding surface, u h is the sliding mode control law, sgn() is the sign function, ω i is the driving wheel speed, ω j is the speed of the passive wheel, k h is the control gain, α and β are sliding mode design parameters; The contact mode aims to prevent the torsional vibration of the transmission system caused by load changes and starting. A reference model of the transmission system is established, and the tracking error of the reference model is used as the input of the adaptive controller to determine the motor command torque. The adaptive control law can be written as: Among them, u z is the adaptive control law, k z is the adaptive control gain, e is the tracking error, is the parameter estimation value, f(x) is the nonlinear function of the system; (7) The additional command torque on the motor side in step (4), the motor command torque in step (6) and the original command torque are summed to obtain the total motor torque, which is output to the transmission system to suppress the torsional vibration of the transmission system.

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