Semi-active control optimization method for distributed driving automobile inerter suspension

Abstract

The invention discloses a distributed driving automobile inerter suspension semi-active control optimization method in the technical field of vehicle suspension vibration isolation. The method comprises the following working steps that 1, a suspension controlled model and an ideal reference model are established; 2, constructing a third-order generalized ground shed semi-active control rule; step 3, carrying out phase-frequency collaborative optimization and topological structure screening; and 4, performing semi-active control optimization on the distributed driving automobile inerter suspension. The method has the advantages that the performance deviation between actual response and an ideal model is reduced, the road friendliness is improved while the riding comfort is guaranteed, and the method adapts to time-varying road excitation.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle suspension vibration isolation, in particular to a semi-active control optimization method for a distributed drive automobile inertia suspension. Background Art

[0002] In-wheel motor-driven vehicles, with their highly integrated electric drive architecture and superior energy efficiency, have become a key development in electric vehicle technology. However, this drive method also presents significant dynamic challenges, primarily the significant increase in unsprung mass and vertical vibration caused by electromagnetic force disturbances. These factors not only exacerbate vehicle acceleration response but also degrade tire contact, making it difficult to balance ride comfort and handling stability at high speeds or in complex road conditions. While traditional passive suspension systems offer a simple structure and high reliability, their inherent frequency response characteristics limit their adaptability to broadband vibrations, making it particularly difficult to effectively suppress the mid- and high-frequency vibration components introduced by in-wheel motors. To overcome this technical bottleneck, inertial volume suspension has emerged. The inertial volume, as a core innovative component, is configured in conjunction with springs and dampers to form a composite suspension topology with inertia control capabilities.

[0003] Although this structure significantly improves the system's freedom of control over frequency-domain vibration, it still has the following problems:

[0004] 1. The control capabilities of traditional low-level models in current semi-active suspension systems are limited, making it impossible to ensure both ride comfort and road friendliness.

[0005] 2. Existing methods lack an effective topology optimization mechanism, resulting in significant performance deviations between theoretical models and actual implementations. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the existing technology and propose a semi-active control optimization method for the inertial suspension of a distributed drive vehicle, which can reduce the performance deviation between the actual response and the ideal model, ensure ride comfort while improving road friendliness and adapting to time-varying road excitations.

[0007] In order to achieve the above-mentioned object of the invention, the semi-active control optimization method of the inertia suspension of a distributed drive vehicle of the present invention adopts the following technical solutions:

[0008] A semi-active control optimization method for an inertia suspension of a distributed drive vehicle includes the following steps:

[0009] Step 1: Establish the controlled suspension model and the ideal reference model;

[0010] Step 2: Construct a third-order generalized ground-shed semi-active control rule;

[0011] Step 3: Phase-frequency coordinated optimization and topology screening;

[0012] Step 4: Optimize the semi-active control of the inertia suspension of the distributed drive vehicle.

[0013] Preferably, the kinetic equation of the ideal reference model in step 1 is:

[0014]

[0015] In formula (1), m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, K(s) is the generalized ground-shed impedance transfer function, and c is the damping coefficient;

[0016] The dynamic equation of the suspension controlled model is as follows:

[0017]

[0018] In formula (2), F ctrl is the damper output force.

[0019] Preferably, the construction of the third-order generalized ground-shed semi-active control rule in step 2 includes the following steps:

[0020] The first step is to establish the ideal damping force function:

[0021] Based on the third-order generalized ground-shed impedance model, the ideal damping force expression under road excitation is established:

[0022]

[0023] In formula (3), F Ks represents the generalized ground-shed damping force, K3(s) is the third-order generalized ground-shed impedance transfer function, and z u is the vertical displacement of the controlled model wheel;

[0024] The second step is to build a controllable damping force model:

[0025] Based on the semi-active quarter-car model, the controllable damping force of the semi-active damper is:

[0026]

[0027] In formula (4), c ctrl represents the controllable damping coefficient, z s is the vertical displacement of the controlled model body;

[0028] The third step is to set the control equivalent conditions:

[0029] Semi-active control rules must meet the following requirements:

[0030]

[0031] At the same time, c min ≤c ctrl ≤c max (6)

[0032] Among them, c min is the minimum damping coefficient provided by the semi-active damper, c max is the maximum damping coefficient provided by the semi-active damper;

[0033] The fourth step is to simplify the semi-active control rules by using switch-type generalized ground-shed control;

[0034] The fifth step is to determine the final standard of the control rule based on the relationship between Laplace transform and Fourier transform.

[0035] Preferably, in the fourth step, switch-type generalized ground-shed control is used to simplify the semi-active control rules, specifically including:

[0036] Substitute equation (7) into equation (8) to simplify it.

[0037]

[0038] s=jω (8)

[0039] Where j is the imaginary unit, ω is the excitation angular frequency of the system, and s is the complex frequency variable in the Laplace transform;

[0040] Simplified formula (9):

[0041]

[0042] Eliminating the imaginary part of formula (9), we get formula (10):

[0043]

[0044] At this time, the controllable damping coefficient is:

[0045]

[0046] And get the criteria for judging the control rules:

[0047]

[0048] Preferably, in the fifth step, based on the relationship between Laplace transform and Fourier transform, equation (13) is obtained:

[0049] ω=2πf=2πvn (13)

[0050] Where n represents the road surface spatial frequency, v represents the vehicle speed, and f is the frequency;

[0051] According to formula (13), ω is obtained, and finally the final standard of the control rule is determined from formula (12).

[0052] Preferably, the phase-frequency coordinated optimization and topology structure screening in step 3 includes the following steps:

[0053] The first step is topology expansion: generating multiple paradigm topologies;

[0054] The second step is phase-frequency characteristic modeling: establishing the transfer function of the relative speed of the wheel speed and the suspension motion under each topology;

[0055] The third step is system dynamics modeling: constructing the Laplace equation of the suspension system controlled by the generalized ground-shelf impedance transfer function;

[0056] Step 4: Control logic definition:

[0057] In the low frequency range, the floor shelf damping and floor shelf inertia take low parameter values. At this time, there is no phase difference between the wheel speed and the relative speed of the suspension movement.

[0058] In the high-frequency range, the floor shed damping and floor shed inertia take high parameter values. At this time, there is a phase difference between the wheel speed and the relative speed of the suspension movement.

[0059] Step 5: Topology screening: Select the topology that meets the control logic definition.

[0060] Preferably, eight topologies are expanded, including T0 topology, T1 topology, T2 topology, T3 topology, T4 topology, T5 topology, T6 topology, and T7 topology. The transfer functions of the wheel speeds of the eight topologies relative to the suspension motion are as follows:

[0061]

[0062]

[0063] Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z uis the vertical displacement of the controlled model wheel, b is the inertia coefficient, k is the spring stiffness, c is the damping coefficient, and s is the complex frequency variable in the Laplace transform.

[0064] Preferably, the Laplace equation in the third step is:

[0065]

[0066] Among them, m s is the sprung mass, m u is the unsprung mass, X2 is z s The Laplace transform of z s is the vertical displacement of the controlled model body, X1 is z u The Laplace transform of z u is the vertical displacement of the controlled model wheel, X r It is z r The Laplace transform of z r is the road roughness displacement, T(s) is the partial impedance transfer function of the suspension system, k t is the equivalent stiffness of the tire, s is the complex frequency variable in the Laplace transform, and K(s) is the generalized ground-shed impedance transfer function.

[0067] Preferably, the topological structure selected in the fifth step has a dynamic equation of one of formula (23) and formula (24):

[0068]

[0069] Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, z3 is the intermediate displacement between the inertia container and the damper, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, F ctrl is the damper output force, c is the damping coefficient, and b is the inertia coefficient.

[0070] Preferably, in step 4, the topology structure selected in step 3 is used to perform semi-active control of the inertial suspension of the distributed drive vehicle.

[0071] This paper proposes a semi-active suspension control method based on a third-order generalized ground-shelf impedance transfer function. Through high-order system modeling and phase-frequency collaborative optimization, it achieves precise control of suspension dynamic characteristics. This method innovatively combines the principle of impedance matching with topology optimization, effectively addressing the limited control range of traditional low-order models and enabling the suspension system to simultaneously meet the dual requirements of low-frequency vibration suppression and high-frequency road adaptation.

[0072] Compared with the prior art, the present invention has the following significant advantages:

[0073] 1. By establishing a third-order impedance transfer function model, the dynamic response accuracy of the system under broadband excitation is significantly improved;

[0074] 2. Adopting intelligent screening mechanism to determine the optimal configuration from multiple topologies, ensuring the best implementation effect of control strategy;

[0075] 3. Semi-active control is achieved using a passive network structure, which significantly reduces the performance deviation between the theoretical model and the actual response while maintaining the system's simplicity and reliability.

[0076] 4. The present invention is suitable for solving multi-objective optimization problems of high-order dynamic systems, ensuring ride comfort while improving road friendliness and adapting to time-varying road surface excitations. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 This is a flow chart of a semi-active control optimization method for inertia suspension of a distributed drive vehicle;

[0078] Figure 2 It is the controlled model diagram of the suspension;

[0079] Figure 3 It is an ideal reference model diagram;

[0080] Figure 4 This is a specific implementation diagram of a suspension system controlled by a generalized ground-shed impedance transfer function;

[0081] Figure 5 It is the phase-frequency characteristic diagram of the generalized ground-shed control logic of the T0 topology, T5 topology and T7 topology;

[0082] Figure 6 It is a phase-frequency characteristic diagram of the generalized ground-shed control logic of the T1 topology, T2 topology, T3 topology, T4 topology and T6 topology;

[0083] Figure 7 It is a controlled model using T0 topology semi-active control;

[0084] Figure 8The controlled model adopts T5 topology semi-active control;

[0085] Figure 9 This is a time domain comparative analysis diagram of vehicle acceleration deviation under three semi-active control strategies;

[0086] Figure 10 This is a time domain comparative analysis diagram of tire dynamic load deviation under three semi-active control strategies;

[0087] Figure 11 This is a time domain comparative analysis diagram of suspension dynamic travel deviation under three semi-active control strategies. DETAILED DESCRIPTION

[0088] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0089] like Figure 1-11 As shown in FIG, a semi-active control optimization method for an inertia suspension of a distributed drive vehicle includes the following steps:

[0090] Step 1: Establish the controlled suspension model and the ideal reference model;

[0091] The dynamic equation of the ideal reference model is:

[0092]

[0093] In formula (1), m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, K(s) is the generalized ground-shed impedance transfer function, and c is the damping coefficient;

[0094] The dynamic equation of the suspension controlled model is as follows:

[0095]

[0096] In formula (2), F ctrl is the damper output force.

[0097] In addition, the random road surface input is:

[0098]

[0099] Where v is the vehicle speed, w(t) is the white noise signal, G q (n0) is the road roughness coefficient.

[0100] Step 2: Construct a third-order generalized ground-shed semi-active control rule, which specifically includes the following steps:

[0101] The first step is to establish the ideal damping force function:

[0102] Based on the third-order generalized ground-shed impedance model, the ideal damping force expression is established under a sinusoidal road surface with an amplitude of 10 mm and a frequency range of [0.01-15] Hz:

[0103]

[0104] In formula (3), F Ks represents the generalized ground-shed damping force, K3(s) is the third-order generalized ground-shed impedance transfer function, and z u is the vertical displacement of the controlled model wheel;

[0105] The second step is to build a controllable damping force model:

[0106] Based on the semi-active quarter vehicle model, such as Figure 3 As shown in Figure 2, the controllable damping force of the semi-active damper is:

[0107]

[0108] In formula (4), c ctrl represents the controllable damping coefficient, z s is the vertical displacement of the controlled model body;

[0109] The third step is to set the control equivalent conditions:

[0110] Semi-active control rules must meet the following requirements:

[0111]

[0112] At the same time, c min ≤c ctrl ≤c max (6)

[0113] Among them, c min is the minimum damping coefficient provided by the semi-active damper, c max is the maximum damping coefficient provided by the semi-active damper;

[0114] The fourth step is to use switch-type generalized ground-shed control to simplify the semi-active control rules, including:

[0115] Substitute equation (7) into equation (8) to simplify it.

[0116]

[0117] s=jω (8)

[0118] Where j is the imaginary unit, ω is the excitation angular frequency of the system, and s is the complex frequency variable in the Laplace transform;

[0119] Simplified formula (9):

[0120]

[0121] Eliminating the imaginary part of formula (9), we get formula (10):

[0122]

[0123] At this time, the controllable damping coefficient is:

[0124]

[0125] And get the criteria for judging the control rules:

[0126]

[0127] The fifth step is to obtain formula (13) based on the relationship between Laplace transform and Fourier transform.

[0128] ω=2πf=2πvn (13)

[0129] Where n represents the road surface spatial frequency, v represents the vehicle speed, and f is the frequency;

[0130] Substituting the parameters n as 0.1 cycles / m and v as 20 m / s, we obtain ω = 12.57 rad / s. The final standard for determining the control rule is:

[0131]

[0132] Step 3, phase-frequency coordinated optimization and topology screening, includes the following steps:

[0133] The first step is to expand the topology structure: after implementing the semi-active control strategy, there are significant system deviations in the body acceleration and dynamic tire load parameters. Therefore, it is proposed to expand the traditional spring-damper parallel suspension structure into multiple paradigm topologies; among them, the topologies are expanded into eight types, including T0 topology, T1 topology, T2 topology, T3 topology, T4 topology, T5 topology, T6 topology and T7 topology, such as Figure 4 As shown;

[0134] The second step is phase-frequency characteristic modeling: establishing the transfer function between the wheel speed and the relative speed of the suspension motion for each topology, and systematically analyzing their phase-frequency response characteristics. The transfer functions of the wheel speed relative to the suspension motion for the eight topologies are as follows:

[0135]

[0136] Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, b is the inertia coefficient, k is the spring stiffness, c is the damping coefficient, and s is the complex frequency variable in the Laplace transform.

[0137] The third step is system dynamics modeling: construct the Laplace equation of the suspension system controlled by the generalized ground-shelf impedance transfer function as follows:

[0138] Laplace's equation is:

[0139]

[0140] Among them, m s is the sprung mass, m u is the unsprung mass, X2 is z s The Laplace transform of z s is the vertical displacement of the controlled model body, X1 is z u The Laplace transform of z u is the vertical displacement of the controlled model wheel, X r It is z r The Laplace transform of z r is the road roughness displacement, T(s) is the partial impedance transfer function of the suspension system, k t is the equivalent stiffness of the tire, s is Laplace The complex frequency variables in the transformation, K ( s ) is the generalized ground-shed impedance transfer function.

[0141] Step 4: Control logic definition:

[0142] In the low-frequency range, the floor shelf damping and floor shelf inertia take low parameter values. At this time, there is no phase difference between the wheel speed and the relative speed of the suspension movement.

[0143] In the high-frequency range, the floor shed damping and floor shed inertia take high parameter values. At this time, there is a phase difference between the wheel speed and the relative speed of the suspension movement.

[0144] Step 5: Topology screening: Based on the phase response characteristics of each topology in the low-frequency range and high-frequency range, select the topology that meets the control logic definition. Its dynamic equation is one of Equation (23) and Equation (24):

[0145]

[0146] Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, z3 is the intermediate displacement between the inertia container and the damper, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, F ctrl is the damper output force, c is the damping coefficient, and b is the inertia coefficient.

[0147] Step 4: Use the topology structure selected in step 3, T0 topology structure or T5 topology structure, to perform semi-active control of the inertial suspension of the distributed drive vehicle.

[0148] based on Figure 9-11 The comparative deviation analysis of the multi-dimensional performance indicators of the suspension system shown in the figure, among which Sban-S3 is the Figure 3 The performance deviation between the semi-active control model and the ideal reference model. Similarly, T0-S3 is the performance deviation of the semi-active control model using the T0 topology structure, and T5-S3 is the performance deviation of the semi-active control model using the T5 topology structure.

[0149] It can be observed that when the semi-active control strategy of the T5 topology is adopted, the deviation amplitude of key parameters such as body acceleration, dynamic tire load and suspension working space is significantly lower than that of the other two semi-active control schemes.

[0150] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A semi-active control optimization method for inertia suspension of a distributed drive vehicle, characterized in that: The following steps are included: Step 1: Establish the controlled suspension model and the ideal reference model; Step 2: Construct a third-order generalized ground-shed semi-active control rule; Step 3: Phase-frequency coordinated optimization and topology screening; Step 4: Optimize the semi-active control of the inertia suspension of the distributed drive vehicle.

2. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 1, characterized in that: The dynamic equation of the ideal reference model in step 1 is: In formula (1), m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, K(s) is the generalized ground-shed impedance transfer function, and c is the damping coefficient; The dynamic equation of the suspension controlled model is as follows: In formula (2), F ctrl is the damper output force.

3. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 1, characterized in that: The construction of the third-order generalized ground-shed semi-active control rule in step 2 includes the following steps: The first step is to establish the ideal damping force function: Based on the third-order generalized ground-shed impedance model, the ideal damping force expression under road excitation is established: In formula (3), F Ks represents the generalized ground-shed damping force, K3(s) is the third-order generalized ground-shed impedance transfer function, and z u is the vertical displacement of the controlled model wheel; The second step is to build a controllable damping force model: Based on the semi-active quarter-car model, the controllable damping force of the semi-active damper is: In formula (4), c ctrl represents the controllable damping coefficient, z s is the vertical displacement of the controlled model body; The third step is to set the control equivalent conditions: Semi-active control rules must meet the following requirements: At the same time, c min ≤c ctrl ≤c max (6) Among them, c min is the minimum damping coefficient provided by the semi-active damper, c max is the maximum damping coefficient provided by the semi-active damper; The fourth step is to simplify the semi-active control rules by using switch-type generalized ground-shed control; The fifth step is to determine the final standard of the control rule based on the relationship between Laplace transform and Fourier transform.

4. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 3, characterized in that: In the fourth step, switch-type generalized ground-shed control is used to simplify the semi-active control rules, including: Substitute equation (7) into equation (8) to simplify it. s=jω (8) Where j is the imaginary unit, ω is the excitation angular frequency of the system, and s is the complex frequency variable in the Laplace transform; Simplified formula (9): Eliminating the imaginary part of formula (9), we get formula (10): At this time, the controllable damping coefficient is: And get the criteria for judging the control rules:

5. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 4, characterized in that: In the fifth step, based on the relationship between Laplace transform and Fourier transform, we get formula (13): ω=2πf=2πvn (13) Where n represents the road surface spatial frequency, v represents the vehicle speed, and f is the frequency; According to formula (13), ω is obtained, and finally the final standard of the control rule is determined from formula (12).

6. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 1, characterized in that: Phase-frequency coordinated optimization and topology screening in step 3 include the following steps: The first step is topology expansion: generating multiple paradigm topologies; The second step is phase-frequency characteristic modeling: establishing the transfer function of the relative speed of the wheel speed and the suspension motion under each topology; The third step is system dynamics modeling: constructing the Laplace equation of the suspension system controlled by the generalized ground-shelf impedance transfer function; Step 4: Control logic definition: In the low-frequency range, the floor shelf damping and floor shelf inertia take low parameter values. At this time, there is no phase difference between the wheel speed and the relative speed of the suspension movement. In the high-frequency range, the floor shed damping and floor shed inertia take high parameter values. At this time, there is a phase difference between the wheel speed and the relative speed of the suspension movement. Step 5: Topology screening: Select the topology that meets the control logic definition.

7. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 6, characterized in that: The topology structures are expanded into eight types, including T0 topology, T1 topology, T2 topology, T3 topology, T4 topology, T5 topology, T6 topology and T7 topology. The transfer functions of the wheel speeds of the eight topologies relative to the suspension motion are as follows: Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, b is the inertia coefficient, k is the spring stiffness, c is the damping coefficient, and s is the complex frequency variable in the Laplace transform.

8. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 6, characterized in that: The Laplace equation in the third step is: Among them, m s is the sprung mass, m u is the unsprung mass, X2 is z s The Laplace transform of z s is the vertical displacement of the controlled model body, X1 is z u The Laplace transform of z u is the vertical displacement of the controlled model wheel, X r It is z r The Laplace transform of z r is the road roughness displacement, T(s) is the partial impedance transfer function of the suspension system, k t is the equivalent stiffness of the tire, s is the complex frequency variable in the Laplace transform, and K(s) is the generalized ground-shed impedance transfer function.

9. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 6, characterized in that: The dynamic equation of the topological structure selected in the fifth step is one of the equations (23) and (24): Among them, m s is the sprung mass, z s is the vertical displacement of the controlled model body, z u is the vertical displacement of the controlled model wheel, z r is the road roughness displacement, z3 is the intermediate displacement between the inertia container and the damper, k is the suspension spring stiffness, k t is the equivalent stiffness of the tire, m us is the mass of the motor stator, m es is the mass of the motor rotor, F r_Z is the unbalanced radial electromagnetic force, F ctrl is the damper output force, c is the damping coefficient, and b is the inertia coefficient.

10. The method for optimizing semi-active control of inertia suspension of a distributed drive vehicle according to claim 1, characterized in that: In step 4, the topology structure selected in step 3 is used to perform semi-active control of the inertial suspension of the distributed drive vehicle.

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