A method for optimizing semi-active control of a distributed drive vehicle inerter suspension

Abstract

The application discloses a kind of distributed drive automobile inertial suspension semi-active control optimization method in the technical field of vehicle suspension vibration isolation, and the method comprises the following working steps: step one, establishing suspension controlled model and ideal reference model;Step two, construct three-order generalized ground semi-active control rule;Step three, phase-frequency collaborative optimization and topological structure screening;Step four, distributed drive automobile inertial suspension semi-active control optimization.The application has the advantages of reducing the performance deviation between actual response and ideal model, improving road friendliness while ensuring ride comfort, and adapting to time-varying road excitation.

Description

Technical Field

[0001] This invention relates to the field of vehicle suspension vibration isolation technology, and in particular to a semi-active control optimization method for distributed drive vehicle inertial capacitance suspension. Background Technology

[0002] In-wheel motor-driven vehicles, with their highly integrated electric drive architecture and superior energy efficiency, have become an important direction for the development of electric vehicle technology. However, this drive method also brings significant dynamic challenges, mainly manifested in the substantial increase in unsprung mass and vertical vibration problems caused by electromagnetic force disturbances. These factors not only exacerbate the vehicle's acceleration response but also lead to a deterioration in tire contact performance, making it difficult to simultaneously meet the dual requirements of ride comfort and handling stability under high-speed driving or complex road conditions. Although traditional passive suspension systems are simple in structure and highly reliable, their inherent frequency response characteristics limit their adaptability to wide-frequency vibrations, especially in effectively suppressing the mid-to-high frequency vibration components introduced by in-wheel motors. To overcome this technical bottleneck, inertial capacitance suspension has emerged, in which the inertial container, as the core innovative component, forms a composite suspension topology with inertial adjustment function through coordinated configuration with springs and dampers.

[0003] While this structure significantly improves the system's degree of freedom in controlling frequency domain vibrations, it still has the following problems:

[0004] 1. The traditional low-order model in the current semi-active suspension system has limited adjustment capabilities and cannot ensure both ride comfort and road friendliness.

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

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

[0007] To achieve the above-mentioned objectives, the distributed drive vehicle inertial capacity suspension semi-active control optimization method of the present invention adopts the following technical solution:

[0008] A semi-active control optimization method for distributed drive vehicle inertial capacitive suspension includes the following steps:

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

[0010] Step 2: Construct third-order generalized semi-active control rules for the ground cover;

[0011] Step 3: Phase-frequency co-optimization and topology selection;

[0012] Step 4: Optimization of semi-active control of inertial capacitive suspension for distributed drive vehicles.

[0013] Preferably, the dynamic equations of the ideal reference model in step one are:

[0014]

[0015] In equation (1), m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Let k be the displacement due to road surface unevenness, and k be the suspension spring stiffness. t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_Z For unbalanced radial electromagnetic force, K(s) is the generalized ground resistance transfer function, and c is the damping coefficient;

[0016] The dynamic equations of the controlled suspension model are as follows:

[0017]

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

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

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

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

[0022]

[0023] In equation (3), F Ks Let K3(s) represent the generalized ground ceiling damping force, and let z be the third-order generalized ground ceiling impedance transfer function. u The vertical displacement of the wheel of the controlled model;

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

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

[0026]

[0027] In equation (4), c ctrl z represents the controllable damping coefficient. s 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 satisfy:

[0030]

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

[0032] Among them, c min It is the minimum damping coefficient provided by the semi-active damper, c max It 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 a switch-type generalized ground cover control.

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

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

[0036] Substituting equation (7) into equation (8) simplifies the expression.

[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 to Equation (9):

[0041]

[0042] Removing the imaginary part from equation (9) yields equation (10).

[0043]

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

[0045]

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

[0047]

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

[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] ω is obtained from equation (13), and the final standard of the control rule is determined from equation (12).

[0052] Preferably, step three, phase-frequency co-optimization and topology selection, includes the following steps:

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

[0054] The second step is to model the phase frequency characteristics: establish the transfer function of the relative velocity between the wheel speed and the suspension motion under each topology.

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

[0056] Step 4, Define the control logic:

[0057] In the low-frequency range, the ground damping and ground inertia are set to 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 damping and floor inertia are set to 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 filtering: Select a topology that meets the control logic definition.

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

[0061]

[0062]

[0063] Where, m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. uLet be the vertical displacement of the wheel of the controlled model, b be the mass coefficient, k be the spring stiffness, c be the damping coefficient, and s be the complex frequency variable in the Laplace transform.

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

[0065]

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

[0067] Preferably, the topology selected in step five has a dynamic equation that is one of equations (23) and (24):

[0068]

[0069] Where, m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Z is the road surface unevenness displacement, z3 is the intermediate displacement between the inertial container and the damper, k is the suspension spring stiffness, and k t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_Z For unbalanced radial electromagnetic force, F ctrl ρ is the output force of the damper, c is the damping coefficient, and b is the mass inertia coefficient.

[0070] Preferably, in step four, the topology selected in step three is used to perform distributed drive vehicle inertial capacity suspension semi-active control.

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

[0072] Compared with existing technologies, 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 wideband excitation is significantly improved;

[0074] 2. An intelligent screening mechanism is used to determine the optimal configuration from multiple topologies, ensuring the best implementation effect of the 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 simplicity and reliability of the system.

[0076] 4. This invention is applicable to 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. Attached Figure Description

[0077] Figure 1 This is a flowchart of a distributed drive vehicle inertial capacitive suspension semi-active control optimization method.

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

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

[0080] Figure 4 This is a diagram illustrating the specific implementation of a suspension system controlled by a generalized ground impedance transfer function.

[0081] Figure 5 This is the phase-frequency response diagram of the generalized ground cover control logic for T0, T5, and T7 topologies;

[0082] Figure 6 It is the phase-frequency response diagram of the generalized ground cover control logic for T1, T2, T3, T4 and T6 topologies;

[0083] Figure 7 This is a semi-active control model using a T0 topology.

[0084] Figure 8This is a semi-active control controlled model using a T5 topology.

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

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

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

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

[0089] like Figure 1-11 As shown, a semi-active control optimization method for a distributed drive vehicle inertial-capacity suspension includes the following steps:

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

[0091] The dynamic equations of the ideal reference model are:

[0092]

[0093] In equation (1), m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Let k be the displacement due to road surface unevenness, and k be the suspension spring stiffness. t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_Z For unbalanced radial electromagnetic force, K(s) is the generalized ground resistance transfer function, and c is the damping coefficient;

[0094] The dynamic equations of the controlled suspension model are as follows:

[0095]

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

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

[0098]

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

[0100] Step two, constructing third-order generalized semi-active control rules for the ground cover, specifically including the following steps:

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

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

[0103]

[0104] In equation (3), F Ks Let K3(s) represent the generalized ground ceiling damping force, and let z be the third-order generalized ground ceiling impedance transfer function. u The vertical displacement of the wheel of the controlled model;

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

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

[0107]

[0108] In equation (4), c ctrl z represents the controllable damping coefficient. s 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 satisfy:

[0111]

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

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

[0114] The fourth step involves using a switch-type generalized canopy control to simplify the semi-active control rules, specifically including:

[0115] Substituting equation (7) into equation (8) simplifies the expression.

[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 to Equation (9):

[0120]

[0121] Removing the imaginary part from equation (9) yields equation (10).

[0122]

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

[0124]

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

[0126]

[0127] Fifth, based on the relationship between the Laplace transform and the Fourier transform, equation (13) is derived.

[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 = 0.1 cycles / m and v = 20 m / s, we get ω = 12.57 rad / s. The final criterion for determining the control rule is:

[0131]

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

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

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

[0135]

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

[0137] The third step is system dynamics modeling: the Laplace equations for the suspension system controlled by the generalized ground resistance transfer function are constructed as follows:

[0138] The Laplace equation is:

[0139]

[0140] Where, m s For the sprung mass, m u Let X2 be the unsprung mass and z be the unsprung mass. s The Laplace transform of z s X1 is the vertical displacement of the controlled model body, and z is the vertical displacement of the model body. u The Laplace transform of z u X represents the vertical displacement of the wheel of the controlled model. r It is z r The Laplace transform of z r Let T(s) be the road surface roughness displacement, T(s) be the partial impedance transfer function of the suspension system, and k be the displacement due to road surface roughness. t Let s be the equivalent stiffness of the tire. Laplace Complex frequency variables in the transformation K ( s ) is the generalized ground cover impedance transfer function.

[0141] Step 4, Define the control logic:

[0142] In the low-frequency range, the ground damping and ground inertia are set to 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 damping and floor inertia are set to 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 selection: Based on the phase response characteristics of each topology in the low-frequency and high-frequency ranges, select a topology that satisfies the control logic definition, whose dynamic equation is one of equations (23) and (24):

[0145]

[0146] Where, m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Z is the road surface unevenness displacement, z3 is the intermediate displacement between the inertial container and the damper, k is the suspension spring stiffness, and k t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_Z For unbalanced radial electromagnetic force, F ctrl ρ is the output force of the damper, c is the damping coefficient, and b is the mass inertia coefficient.

[0147] Step four: Using the topology selected in step three, either the T0 topology or the T5 topology, perform distributed drive vehicle inertial capacity suspension semi-active control.

[0148] based on Figure 9-11 The comparison and deviation analysis of the multidimensional performance indicators of the suspension system shown is illustrated, where Sban-S3 represents the performance index of the suspension system using... Figure 3 The performance deviation between the semi-active control model and the ideal reference model is represented by T0-S3, which represents the performance deviation of the semi-active control model using the T0 topology, and T5-S3 represents the performance deviation of the semi-active control model using the T5 topology.

[0149] It can be observed that when the semi-active control strategy with T5 topology is adopted, the deviation of key parameters such as vehicle 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 above are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. 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 shall fall within the protection scope of the present invention.

Claims

1. A method for optimizing semi-active control of a distributed drive vehicle's inertial capacitance suspension, characterized in that, The work includes the following steps: Step 1: Establish the controlled suspension model and the ideal reference model; Step two, constructing third-order generalized semi-active control rules for the ground cover, including the following steps: The first step is to establish the ideal damping force function: Based on the third-order generalized ground impedance model, the expression for the ideal damping force under road surface excitation is established: （3） In equation (3), F Ks Let K3(s) represent the generalized ground ceiling damping force, and let z be the third-order generalized ground ceiling impedance transfer function. u The vertical displacement of the wheel of the controlled model; The second step is to construct a controllable damping force model: Based on the semi-active quarter-vehicle model, the controllable damping force of the semi-active damper is: （4） In equation (4), c ctrl z represents the controllable damping coefficient. s The vertical displacement of the controlled model body; The third step is to set the control equivalent conditions: Semi-active control rules must satisfy: （5） at the same time, (6) in, It is the minimum damping coefficient provided by the semi-active damper. It is the maximum damping coefficient provided by the semi-active damper; The fourth step is to simplify the semi-active control rules by using a switch-type generalized ground cover control. The fifth step is to determine the final standard for the control rules based on the relationship between the Laplace transform and the Fourier transform. Step 3, Phase-Frequency Co-optimization and Topology Selection, includes the following steps: The first step is topology expansion: generating multiple paradigm topologies; The second step is to model the phase frequency characteristics: establish the transfer function of the relative velocity between the wheel speed and the suspension motion under each topology. The third step is system dynamics modeling: constructing the Laplace equation for the suspension system controlled by the generalized ground impedance transfer function; Step 4, Define the control logic: In the low-frequency range, the ground damping and ground inertia are set to 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 damping and floor inertia are set to 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 filtering: Select a topology that meets the control logic definition; Step four: Using the topology selected in step three, perform distributed drive vehicle inertial capacity suspension semi-active control.

2. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 1, characterized in that, The dynamic equations of the ideal reference model in step one are: （1） In equation (1), m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Let k be the displacement due to road surface unevenness, and k be the suspension spring stiffness. t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_z For unbalanced radial electromagnetic force, K(s) is the generalized ground impedance transfer function, and c is the damping coefficient; The dynamic equations of the controlled suspension model are as follows: （2） In equation (2), F ctrl This is the output force of the damper.

3. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 1, characterized in that, Step 2, step 4, uses a switch-type generalized canopy control to simplify the semi-active control rules, specifically including: Substituting equation (7) into equation (8) simplifies the expression. （7） （8） in, It is a virtual part unit. ω is the excitation angular frequency of the system, and s is the complex frequency variable in the Laplace transform. Simplified to form (9): （9） Removing the imaginary part from equation (9) yields equation (10). （10） At this point, the controllable damping coefficient is: （11） And obtain the criteria for judging control rules: （12）。 4. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 3, characterized in that, In the fifth step of step two, based on the relationship between the Laplace transform and the Fourier transform, equation (13) is derived. （13） Where n represents the road surface spatial frequency, v represents the vehicle speed, and f is the frequency; ω is obtained from equation (13), and the final standard of the control rule is determined from equation (12).

5. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 1, characterized in that, The topology is extended to eight types: T0, T1, T2, T3, T4, T5, T6, and T7. The transfer functions of wheel speed relative to suspension motion for these eight topologies are as follows: （14） （15） （16） （17） （18） （19） （20） （21） Where, m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let be the vertical displacement of the wheel of the controlled model, b be the mass coefficient, k be the spring stiffness, c be the damping coefficient, and s be the complex frequency variable in the Laplace transform.

6. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 1, characterized in that, In the third step of step three, the Laplace equation is: （22） Where, m s For the sprung mass, m u Let X2 be the unsprung mass and z be the unsprung mass. s The Laplace transform of z s X1 is the vertical displacement of the controlled model body, and z is the vertical displacement of the model body. u The Laplace transform of z u X represents the vertical displacement of the wheel of the controlled model. r It is z r The Laplace transform of z r Let T(s) be the road surface roughness displacement, T(s) be the partial impedance transfer function of the suspension system, and k be the displacement due to road surface roughness. t Let be the tire equivalent stiffness, s be the complex frequency variable in the Laplace transform, and K(s) be the generalized ground impedance transfer function.

7. The method for optimizing semi-active control of distributed drive vehicle inertial capacitance suspension according to claim 1, characterized in that, The topological structure selected in step three, fifth step, has a dynamic equation that is one of equations (23) and (24): （23） （24） Where, m s For the sprung mass, z s Let z be the vertical displacement of the controlled model body. u Let z be the vertical displacement of the wheel of the controlled model. r Z is the road surface unevenness displacement, z3 is the intermediate displacement between the inertial container and the damper, k is the suspension spring stiffness, and k t For the tire's equivalent stiffness, m us m is the mass of the motor stator. es For the mass of the motor rotor, F r_z For unbalanced radial electromagnetic force, F ctrl ρ is the output force of the damper, c is the damping coefficient, and b is the mass inertia coefficient.

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