Three-cylinder engine semi-active suspension control method, computer storage medium and program

Abstract

The invention discloses a three-cylinder engine semi-active suspension control method which comprises the following steps: establishing a three-cylinder engine vibration model, and calculating vertical excitation force of an engine according to parameters of the three-cylinder engine; establishing an engine semi-active suspension kinetic equation and a system state space expression according to the engine vertical excitation force, the vehicle suspension parameters and the engine semi-active suspension parameters; external interference of the system is used as a new state variable, and an improved expansion observer is constructed; establishing a global sliding mode controller by taking the vehicle body vibration acceleration and the suspension dynamic deflection as control objects; an improved expansion observer is integrated in a global sliding mode controller, state data of the expansion observer is transmitted to the global sliding mode controller based on a three-cylinder engine vibration model and read sensor signals, and the global sliding mode controller controls engine suspension. The method is high in control efficiency and accuracy and good in robustness.

Description

Technical Field

[0001] The invention relates to an engine suspension control method, a computer storage medium and a program, and belongs to the technical field of engine arrangement. Background Art

[0002] The engine is the main source of automobile vibration and noise. At present, the engine mount is mainly used for vibration isolation and noise reduction. Most engine mounts use rubber mounts or hydraulic resistance mounts, which have good vibration isolation and noise reduction effects. The engine mount is divided into active mounts and passive mounts. The passive mount (engine hydraulic mount) has the functions of support, limit, and low-frequency vibration isolation (less than 20 Hz). When the excitation frequency is high, the ordinary hydraulic mount will undergo dynamic hardening, the dynamic stiffness will increase, the vibration reduction and noise reduction effect will deteriorate, and the actuator will begin to work. The engine active mount includes fully active mount and semi-active mount. The engine semi-active mount is mainly composed of passive hydraulic mount and actuator.

[0003] The control technologies for active engine mounts mainly include PID control, fuzzy control, neural network control, sliding mode control based on extended observer, etc. The main problems include: The object of treatment is active suspension, which relies solely on external force to achieve vibration reduction effect, ignoring mature passive suspension technology, so the system energy consumption is high; insufficient attention is paid to the actual vibration characteristics of the engine, and the engine type is often directly ignored, especially parameters such as the number of engine cylinders and engine speed, and only a simple engine vibration model is used in the model; since the engine suspension system has many parameters, and some parameters cannot be directly measured or the measurement cost is too high (such as suspension acceleration), it is difficult to achieve precise control relying solely on the control strategy itself. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the task of the present invention is to provide a three-cylinder engine semi-active mount control method, the purpose of which is to improve the control accuracy of the vibration characteristics of the three-cylinder engine, improve the robustness of the system's response throughout the entire process, and enhance the control effect. The present invention also provides a computer storage medium and a program for implementing the control method.

[0005] The technical solution of the present invention is as follows: A three-cylinder engine semi-active suspension control method comprises the following steps: Establish a three-cylinder engine vibration model and calculate the vertical exciting force of the engine based on the three-cylinder engine parameters; The dynamic equation of the engine semi-active mount and the system state space expression are established based on the engine vertical exciting force, the vehicle suspension parameters and the engine semi-active mount parameters; Taking the external disturbance of the system as a new state variable, an improved extended observer is constructed; Taking the vehicle body vibration acceleration and suspension dynamic deflection as control objects, a global sliding mode controller is established. An improved extended observer is integrated into a global sliding mode controller, and based on a three-cylinder engine vibration model and read sensor signals, state data of the extended observer is transmitted to the global sliding mode controller, which controls the engine semi-active mount.

[0006] Furthermore, the calculation of the vertical exciting force of the engine is to regard the three-cylinder in-line engine as three single-cylinder engines connected by a crankshaft, replace the mass of the entire crank connecting rod with the equivalent mass concentrated on the crankpin and the piston pin, and calculate the resultant force of the crankshaft rotation centrifugal force in the vertical direction and the resultant force of the reciprocating inertia force to obtain the vertical exciting force of the engine.

[0007] Furthermore, the vertical exciting force of the engine is expressed as , in, F is the vertical exciting force of the engine, is the equivalent mass concentrated on the crank pin, is the equivalent mass concentrated on the piston pin, r is the crank radius, is the crankshaft angular velocity, For the i The angle between the first crank and the second crank.

[0008] Furthermore, the dynamic equation of the engine semi-active mount is: , in, They are engine mass and body mass. are the stiffness and damping coefficient of the passive suspension, is the tire stiffness, is the suspension damping coefficient, is the vertical displacement of the engine, is the vertical displacement of the vehicle body, U is the dynamic deflection produced by the actuator.

[0009] Furthermore, the system state space expression is: , , , , , , in, External interference to the system.

[0010] Furthermore, the expression of the improved extended observer is: , in, represent The estimated value of represents the estimation error, p is the inverse of the interference term, .

[0011] Furthermore, the sliding mode surface of the global sliding mode controller is: , where c is the control variable constant, is the global sliding mode control parameter, represents the target position variable, .

[0012] Furthermore, the sliding mode control rate of the global sliding mode controller integrated with the improved extended observer is .

[0013] Another technical solution of the present invention is: a computer storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the aforementioned three-cylinder engine semi-active suspension control method is implemented.

[0014] Another technical solution of the present invention is: a computer program, which, when executed by a processor, implements the aforementioned three-cylinder engine semi-active suspension control method.

[0015] The advantages of the present invention compared with the prior art are: 1) The vibration control effect is significantly improved, while the dynamic deflection of the engine mount is reduced.

[0016] Since this patent introduces the vibration model of the three-cylinder engine, and takes the suspension vibration acceleration and the engine suspension dynamic deflection as the control objects, the control of the three-cylinder engine is very targeted. At the same time, the suspension disturbance is used as a variable, and an extended observer is established, so that the system can estimate the state parameters and the disturbance of the system in real time, and can ensure the accuracy and rapid convergence of the observation error. Therefore, the engine semi-active suspension system can significantly reduce the transmission of engine vibration and effectively reduce the dynamic deflection of the engine suspension.

[0017] 2) The responsiveness and accuracy of the control system are improved.

[0018] Due to the high-gain error feedback adopted by the extended observer and the introduction of nonlinear compensation terms, the dynamics of the observer are higher than the dynamics of the system, which can effectively observe and suppress various interference terms in the system, ensure the rapid convergence of the observation error and sufficiently high parameter estimation accuracy, thereby improving the control accuracy of the controller. When the system deviates, the extended observer can make adjustments quickly, so it can well overcome the delay problem of the traditional sliding mode controller, estimate the change of the suspension system state more quickly, update the compensation coefficient online, and improve the stability and rapid response performance of the semi-active suspension.

[0019] 3) The control system has the robustness of the entire response process.

[0020] The system introduces a global sliding mode controller. The robustness of traditional sliding mode control is only reflected in the sliding mode, while the global sliding mode controller is based on the dynamic nonlinear sliding surface equation to realize the non-robustness of the sliding mode control in the arrival motion stage. The introduction of the global sliding mode function ensures that the system is also robust in the arrival mode. Therefore, the robustness of the system's full response process overcomes the characteristic of the traditional sliding mode control that the arrival mode is not robust, and the overall control performance of the system is improved.

[0021] 4) The integration of the control system improves the control performance of the system.

[0022] By integrating the extended observer of the global sliding mode controller, the control efficiency and accuracy of the system are significantly improved on the basis of noise suppression. The coordination between the sliding mode controller and the observer is also improved, thus optimizing the overall performance of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flow chart of the semi-active suspension control system of a three-cylinder engine.

[0024] Figure 2 Schematic diagram of the steps of the semi-active mount control method for a three-cylinder engine.

[0025] Figure 3 This is a comparison chart of the suspension dynamic travel of the three-cylinder engine semi-active suspension control method of the present invention and the traditional sliding mode control.

[0026] Figure 4 This is a comparison diagram of the suspension vibration acceleration of the three-cylinder engine semi-active suspension control method of the present invention and the traditional sliding mode control. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the embodiments, but are not intended to limit the present invention.

[0028] Please combine Figure 1As shown, this embodiment constructs a three-cylinder engine semi-active suspension control system including a global sliding mode controller integrating an improved expanded state observer. The improved expanded state observer reads the sensor signal in real time and transmits the observer state data to the global sliding mode controller. The global sliding mode controller calculates and outputs a control force U that can ensure the robustness of the system based on the observer state data, thereby realizing the control of the engine semi-active suspension system over the vehicle body vibration acceleration and suspension dynamic deflection.

[0029] Please refer to the specific three-cylinder engine semi-active suspension control method implemented by the three-cylinder engine semi-active suspension control system. Figure 2 As shown, the following steps are included.

[0030] 1. Establish a three-cylinder engine vibration model and calculate the vertical exciting force of the engine based on the three-cylinder engine parameters.

[0031] The three-cylinder in-line engine can be regarded as three single-cylinder engines connected by a crankshaft. The interference force acting on the entire cylinder body should be a set of spatial force systems composed of the interference forces on each single cylinder.

[0032] For the convenience of calculation, when discussing engine vibration, the mass of the entire crank and connecting rod is replaced by two equivalent masses concentrated on the crank pin and the piston pin, while ensuring that the center of gravity position and the total mass remain unchanged. is the equivalent mass concentrated on the crank pin, is the equivalent mass concentrated on the piston pin.

[0033] set up For the i The angle between the first crank and the first crank. Since it is a three-cylinder engine, the resultant force of the crankshaft rotation centrifugal force in the vertical direction is:

[0034] In formula (1), is the crankshaft angular velocity, y Indicates the direction of the plumb bob.

[0035] The resultant of the reciprocating inertia force is:

[0036] In formula (2), is the ratio of crank radius to connecting rod length.

[0037] From equations (1) and (2), the total plumb disturbance force F can be obtained, which is the engine vibration excitation force and serves as the input signal of the semi-active mount:

[0038] 2. The dynamic equation of the engine semi-active mount and the system state space expression are established based on the engine vertical exciting force, vehicle suspension parameters and engine semi-active mount parameters.

[0039] Dynamic equation of engine semi-active mount:

[0040] In formula (4), They are engine mass and body mass. are the stiffness and damping coefficient of the passive suspension, is the tire stiffness, is the suspension damping coefficient, is the vertical displacement of the engine, is the vertical displacement of the vehicle body, U is the dynamic deflection generated by the actuator. Since the tire stiffness is much greater than the suspension stiffness, the suspension stiffness is ignored in this model.

[0041] According to formula (4), the state space expression of the system is established:

[0042] In formula (5) . is the external interference of the system, and the matrices A, B, E, and G are:

[0043]

[0044]

[0045]

[0046] 3. Take the external disturbance of the system as a new state variable and construct an improved extended observer.

[0047] Due to external interference in the system , the traditional observer cannot guarantee the anti-interference ability of the system, so the extended observer is designed as:

[0048] In formula (6) represent The estimated value of represents the estimation error, p is the inverse of the interference term, and is guaranteed to be bounded.

[0049] Select the observer gain coefficient matrix , so that the observation error of the observer approaches 0.

[0050] It can be seen from formula (6) that the extended observer takes the external disturbance as a new state variable. The stability analysis of the disturbance term is performed. From formula (6), we can get:

[0051] Construct the Lyapunov function:

[0052] make:

[0053] Pick , which can be achieved when When , the observer converges to the error, that is: .

[0054] Polynomial The Hurwitz condition is satisfied. Since the extended observer uses high-gain error feedback, the dynamics of the observer are much higher than the dynamics of the system, which is equivalent to adding a fast-changing subsystem. Therefore, the rapid convergence of the observation error and sufficiently high estimation accuracy can be guaranteed.

[0055] 4. Taking the vehicle body vibration acceleration and suspension dynamic deflection as the control objects, a global sliding mode controller is established.

[0056] Due to the disturbance in the system and the uncertainty of the vehicle itself, a global sliding mode controller is selected to ensure that the system has sufficient robustness.

[0057] The control objective of the system is to reduce the changes in vehicle body acceleration caused by engine vibration, while preventing excessive deflection of the engine semi-active mount from causing damage to components. Therefore, the tracking error is defined and the observation value of the expanded observer is introduced.

[0058] make , the error parameter is: Represents the target position variable.

[0059] The sliding surface of the global sliding mode controller is designed as , where c is the control variable constant, is the global sliding mode control parameter.

[0060] but: .

[0061] The sliding mode control rate based on the extended observer is: .

[0062] In order to satisfy the global nature of sliding mode control, The selection of must meet three conditions. First, ; Second, when hour, ; Third, has a first-order derivative. Therefore, choose , k The value determines the robustness of the arrival state.

[0063] Finally, the improved extended observer is integrated into the global sliding mode controller. Based on the three-cylinder engine vibration model and the read sensor signals, the state data of the extended observer is transmitted to the global sliding mode controller, which then controls the engine mount.

[0064] Depend on Figure 3 , Figure 4 It can be seen that compared with the traditional sliding mode control, the global sliding mode control with expanded observer adopted in this patent can better control the vibration of the suspension. At the same time, it is also superior to the traditional sliding mode control in terms of suspension dynamic stroke, so the system control performance is greatly improved.

[0065] Finally, it should be pointed out that the specific methods of the above embodiments can form a computer program product. Therefore, the computer program product implemented in this application can be stored on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.).

Claims

1. A three-cylinder engine semi-active suspension control method, characterized in that: Includes steps: Establish a three-cylinder engine vibration model and calculate the vertical exciting force of the engine based on the three-cylinder engine parameters; The dynamic equation of the engine semi-active mount and the system state space expression are established based on the engine vertical exciting force, the vehicle suspension parameters and the engine semi-active mount parameters; Taking the external disturbance of the system as a new state variable, an improved extended observer is constructed; Taking the vehicle body vibration acceleration and suspension dynamic deflection as control objects, a global sliding mode controller is established. An improved extended observer is integrated into a global sliding mode controller, and based on a three-cylinder engine vibration model and read sensor signals, state data of the extended observer is transmitted to the global sliding mode controller, which controls the engine mount.

2. The three-cylinder engine semi-active mount control method according to claim 1, characterized in that: The calculation of the vertical exciting force of the engine is to regard the three-cylinder in-line engine as three single-cylinder engines connected by a crankshaft, replace the mass of the entire crank connecting rod with the equivalent mass concentrated on the crankpin and the piston pin, calculate the resultant force of the crankshaft rotation centrifugal force in the vertical direction and the resultant force of the reciprocating inertia force to obtain the vertical exciting force of the engine.

3. The three-cylinder engine semi-active mount control method according to claim 2, characterized in that: The expression of the engine vertical exciting force is: ， in, F is the vertical exciting force of the engine, is the equivalent mass concentrated on the crank pin, is the equivalent mass concentrated on the piston pin, r is the crank radius, is the crankshaft angular velocity, For the i The angle between the first crank and the second crank.

4. The three-cylinder engine semi-active mount control method according to claim 1, characterized in that: The dynamic equation of the engine semi-active mount is: ， in, They are engine mass and body mass. are the stiffness and damping coefficient of the passive suspension, is the tire stiffness, is the suspension damping coefficient, is the vertical displacement of the engine, is the vertical displacement of the vehicle body, U is the dynamic deflection produced by the actuator.

5. The three-cylinder engine semi-active mount control method according to claim 4, characterized in that: The system state space expression is: ， ， ， ， ， ， in, External interference to the system.

6. The three-cylinder engine semi-active mount control method according to claim 4, characterized in that: The expression of the improved extended observer is: ， in, represent The estimated value of represents the estimation error, p is the inverse of the interference term, .

7. The three-cylinder engine semi-active mount control method according to claim 4, characterized in that: The sliding surface of the global sliding mode controller is: , where c is the control variable constant, is the global sliding mode control parameter, represents the target position variable, .

8. The three-cylinder engine semi-active mount control method according to claim 7, characterized in that: The sliding mode control rate of the global sliding mode controller integrated with the improved extended observer is 。 9. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the three-cylinder engine semi-active mount control method according to any one of claims 1 to 8 is implemented.

10. A computer program, characterized in that When the computer program is executed by a processor, the three-cylinder engine semi-active mount control method according to any one of claims 1 to 8 is implemented.

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