A bus intelligent suspension system and control method thereof

Abstract

The present invention provides a passenger car intelligent suspension system and a control method thereof. A multi-sensor network includes a road condition perception sensor installed above the front glass of the vehicle to obtain the expected characteristics of the road ahead; a passenger comfort feedback sensor installed on the passenger seat cushion and seat back to obtain the vertical acceleration curve of the seat position over time; an acceleration sensor and an inclination sensor are both installed near the center of mass of the vehicle, the displacement sensor is used to obtain the position of the vehicle in real time, and the inclination sensor is used to obtain the roll angle and pitch angle of the vehicle in real time; an adaptive actuator includes a front and rear active stabilizer bar system, including a front active stabilizer bar system and a rear active stabilizer bar system, both of which are arranged between two adjacent air springs for active roll suppression of the vehicle; and a front and rear adjustable damping shock absorber system, which is installed near the front and rear axle air springs of the vehicle to adjust the damping characteristics of the shock absorber in real time according to vehicle requirements.

Description

Technical Field

[0001] The present invention relates to the field of buses and bus parts, and in particular to a bus intelligent suspension system and a control method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Traditional bus suspension systems mainly rely on mechanical structures for vibration absorption and body posture adjustment, which makes it difficult to cope with high-speed changing road conditions and dynamic loads, and lacks the ability to fine-tune and actively intervene in the vehicle's driving status. With the development of intelligent driving technology, the demand for intelligent bus suspension systems is increasing, requiring them to be able to perceive the environment in real time and accurately adjust various components to optimize driving performance.

[0004] The schematic diagram of the currently known technical solutions is as follows Figure 1 As shown in the figure, the height of the air spring can be adjusted by controlling the solenoid valve to charge and discharge air, thereby adjusting the body posture. This technology can only adjust the body height, but cannot sense road conditions in real time, and cannot actively intervene in suspension components. It has limited effect on improving the handling stability and ride smoothness of buses, and has great limitations, making it difficult to meet the requirements of high-end customers for vehicle stability and ride comfort. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a bus intelligent suspension system and a control method thereof. The present invention significantly improves the maneuverability, smoothness, safety performance and energy efficiency of the bus under various road conditions by integrating advanced sensing technology, high-performance computing platform, real-time data analysis and processing, and adaptive control strategy.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides an intelligent suspension system for a passenger car.

[0008] A bus intelligent suspension system includes: a multi-sensor network, a controller and an adaptive actuator.

[0009] The multi-sensor network includes a road condition perception sensor installed above the front glass of the vehicle to obtain the expected characteristics of the road ahead; a passenger comfort feedback sensor installed on the passenger seat cushion and seat back to obtain the vertical acceleration curve of the seat position over time; an acceleration sensor and an inclination sensor, both installed near the center of mass of the vehicle, a displacement sensor for obtaining the position of the vehicle in real time, and an inclination sensor for obtaining the roll angle and pitch angle of the vehicle in real time;

[0010] Adaptive actuators, including front and rear active stabilizer bar systems, including front active stabilizer bar systems and rear active stabilizer bar systems, both of which are arranged between two adjacent air springs for active roll suppression of the vehicle; front and rear adjustable damping shock absorber systems, which are installed near the front and rear axle air springs of the vehicle for real-time adjustment of the shock absorber damping characteristics according to vehicle requirements;

[0011] The controller is used to calculate the optimal suspension parameter settings in multiple future time steps based on the current driving state of the vehicle and the expected characteristics of the road ahead obtained by the multi-sensor network, using a model prediction algorithm, and guide the front and rear active stabilizer bar systems and / or front and rear adjustable damping shock absorber systems to adjust parameters to minimize vibration, maintain vehicle body stability, and optimize vehicle dynamic response.

[0012] Furthermore, the adaptive actuator also includes a variable volume air spring auxiliary air chamber installed near the air spring and communicated with the inner cavity of the air spring.

[0013] Furthermore, the multi-sensor network also includes a height sensor and a pressure sensor installed on the vehicle.

[0014] A second aspect of the present invention provides a method for controlling a bus intelligent suspension system.

[0015] A bus intelligent suspension system control method, applied to the bus intelligent suspension system described in the first aspect, comprises:

[0016] Use a multi-sensor network to obtain the current driving status of the bus and the expected characteristics of the road ahead;

[0017] Based on the current driving state of the bus and the expected characteristics of the road ahead, the controller is used to determine the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate and equivalent mean value of vertical vibration at the measuring point position in the next time step;

[0018] Based on the comparison between the roll stability coefficient, longitudinal impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position and the corresponding threshold value at the next time step, the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions are controlled to adjust the above parameters to minimize vibration, keep the vehicle body stable and optimize the vehicle dynamics response.

[0019] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters includes:

[0020] Determine the roll stiffness provided by the air springs, the combined roll stiffness provided by the suspension guide and front axle, and the roll stiffness provided by the stabilizer bar system;

[0021] The roll angle stiffness of the next time step is calculated according to the roll angle stiffness provided by the air spring, the composite roll angle stiffness provided by the suspension guide mechanism and the front axle, and the roll angle stiffness provided by the stabilizer bar system;

[0022] If the roll stability coefficient at the next time step is less than the ideal roll stability coefficient, a force in the opposite direction is pre-applied to the stabilizer bar ends of the front and rear active stabilizer bar systems to increase the roll angle stiffness of the stabilizer bar and thus increase the roll stability coefficient of the entire vehicle.

[0023] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters also includes:

[0024] Determine the pitch angle stiffness, sprung mass, and pitch moment arm;

[0025] Calculate the pitch impedance coefficient for the next time step based on the pitch angle stiffness, sprung mass and pitch moment arm;

[0026] If the pitch impedance coefficient at the next time step is less than the ideal pitch impedance coefficient, the volume of the variable volume air spring auxiliary air chamber is reduced, and the damping of the front and rear adjustable damping shock absorber systems is increased to increase the pitch impedance coefficient.

[0027] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters also includes:

[0028] Determine the effective pressure-bearing area of ​​the air spring at the measuring point height, the rate of change of the effective area, the relative air pressure of the air spring at the height, and the total volume of the air spring at the height;

[0029] Calculate the frequency deviation value of the next time step according to the effective pressure-bearing area of ​​the air spring at the height of the measuring point, the rate of change of the effective area, the relative air pressure of the air spring at the height, and the total volume of the air spring at the height;

[0030] If the frequency deviation value of the next time step exceeds the frequency deviation limit, the volume of the auxiliary air chamber of the variable volume air spring is adjusted to reduce the stiffness of the air spring assembly.

[0031] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters also includes:

[0032] Determine the sprung mass and cornering stiffness of each tire;

[0033] According to the sprung mass and cornering stiffness of each tire, the understeer gradient value of the next time step is calculated;

[0034] If the understeer gradient value at the next time step is less than zero, increase the roll stiffness of the front suspension and reduce the roll stiffness of the rear suspension in the front and rear active stabilizer bar system until the understeer gradient value is equal to the ideal value; if the understeer gradient value at the next time step is greater than the allowable limit of the understeer gradient value, reduce the roll stiffness of the front suspension in the front and rear active stabilizer bar system and increase the roll stiffness of the rear suspension until the understeer gradient value is equal to the ideal value.

[0035] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters also includes:

[0036] Determine the tire sideslip angle, inner wheel turning angle, ideal outer wheel turning angle, and actual outer wheel turning angle;

[0037] Calculate the Ackerman rate of the next time step according to the tire sideslip angle, the inner wheel turning angle, the ideal outer wheel turning angle and the actual outer wheel turning angle;

[0038] If the Ackerman rate in the next time step exceeds the allowable limit of the Ackerman rate, the vehicle instrument panel will be controlled to sound an alarm.

[0039] Further, the process of determining the comparison between the roll stability coefficient, the pitch impedance coefficient, the offset frequency value, the understeering gradient value, the Ackerman rate or the vertical vibration of the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, the front and rear adjustable damping shock absorber systems and / or the variable volume air spring auxiliary air chamber to adjust the above parameters also includes:

[0040] Determine the curve of vertical acceleration of the passenger seat position over time and calculate the weighted acceleration root mean square;

[0041] The equivalent mean value of the vertical vibration at the measuring point position at the next time step is calculated based on the weighted root mean square acceleration; if the equivalent mean value of the vertical vibration at the measuring point position at the next time step is greater than the equivalent mean value limit of the vertical vibration, the damping of the front and rear adjustable damping shock absorber systems is controlled to be reduced until the equivalent mean value of the vertical vibration at the measuring point position at the next time step is equal to the equivalent mean value limit of the vertical vibration.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention provides a bus intelligent suspension system and control method thereof, which aims to improve the comfort, safety and handling performance of bus driving. By integrating advanced sensor technology, real-time data analysis and processing, and adaptive control strategy, it realizes precise control and active adaptation of the vehicle body posture under complex road conditions. The system not only significantly improves the passenger riding experience, but also enhances the stability and energy efficiency of the vehicle under different load conditions and driving environments.

[0044] The adaptive adjustment and predictive control passenger bus intelligent suspension system provided by the present invention, with its precise perception, autonomous adjustment and forward-looking control capabilities, can ensure that the bus has excellent driving quality, stability and energy-saving performance under various complex road conditions. The application of this system is expected to lead the bus industry to a higher level of intelligence, which will not only improve the travel experience of passengers, but also help public transportation operators to achieve a dual improvement in operating efficiency and economic benefits. With the development of autonomous driving technology, this intelligent suspension system will become an indispensable core component of future autonomous driving buses, which is of great significance for promoting the green and intelligent transformation of the entire transportation industry. This solution can replace traditional bus air suspension systems and electronic body lifting systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0046] Figure 1 The present invention is a schematic diagram of the system structure of an existing air suspension bus electronic body lifting system;

[0047] Figure 2 The present invention is a framework diagram of a bus intelligent suspension system;

[0048] Figure 3 The structure diagram of the intelligent suspension system for passenger cars shown in the present invention;

[0049] Figure 4 A schematic diagram of an installation position of a road condition recognition sensor and a passenger comfort feedback sensor shown in the present invention;

[0050] Figure 5 This is a schematic diagram showing the definitions of various identifiers of the stabilizer bar system of the present invention. DETAILED DESCRIPTION

[0051] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0052] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0054] Embodiment 1

[0055] like Figure 3 , Figure 4 As shown, this embodiment provides a bus intelligent suspension system, including:

[0056] Multi-sensor network: equipped with gyroscopes, accelerometers, inclination sensors, displacement sensors, height sensors, pressure sensors, road condition perception sensors (such as lidar or cameras), passenger comfort feedback sensors, etc., for real-time monitoring of key parameters such as vehicle body vibration, posture, and road surface information.

[0057] High-performance control unit (ECU): equipped with a dedicated processor and embedded software, responsible for receiving and processing sensor data, executing control algorithms, and generating adjustment instructions.

[0058] Adaptive actuator: including but not limited to variable volume air spring auxiliary chamber, adjustable damping shock absorber, electric air pressure height adjustment device (solenoid valve), active stabilizer bar system, etc., responding to controller instructions and dynamically adjusting the working state of the suspension. The variable volume air spring auxiliary chamber is installed near the air spring and communicates with the inner cavity of the air spring.

[0059] Figure 3The figure shows an intelligent suspension system for buses, including a sensor network formed by the fusion of multiple sensors, a high-performance controller (ECU) and an adaptive actuator. The sensors mainly include road condition perception sensors, height sensors, pressure sensors, displacement sensors, acceleration sensors, inclination sensors, passenger comfort feedback sensors, etc.; the adaptive actuators mainly include adjustable damping shock absorbers, electric pneumatic height adjustment devices (solenoid valves), active stabilizer bar systems, etc. The multi-sensor combination is used to accurately measure the current driving state of the bus (such as body acceleration, lateral acceleration, roll angle, pitch angle, wheel load distribution, etc.) and the expected characteristics of the road ahead (such as bumpiness, slope, curve curvature, etc.). The high-performance controller (ECU) is equipped with a dedicated processor and embedded software to receive and process sensor data, build an accurate vehicle-road interaction model, and use a model prediction algorithm to calculate the optimal suspension parameter settings in multiple future time steps, guiding the suspension system to make forward-looking parameter adjustments to minimize vibration, keep the body stable, and optimize vehicle dynamics response. The adaptive actuator is used to receive and respond to ECU instructions and dynamically adjust the suspension parameters.

[0060] like Figure 4 As shown, the present invention adds a road condition perception sensor for accurately measuring the expected characteristics of the road ahead, such as the degree of bumps, slope, curve curvature, etc.); adds an acceleration sensor for measuring the acceleration and lateral acceleration of the vehicle; adds a displacement sensor for real-time measurement of the position state of the vehicle; adds an inclination sensor for real-time measurement of the roll angle and pitch angle of the vehicle; adds a passenger comfort feedback sensor for real-time measurement of passenger comfort in the passenger area; the ECU adds a vehicle-road interaction model establishment function, adopts a model prediction algorithm to calculate the optimal suspension parameter setting in multiple future time steps, and guides the suspension system to make forward-looking parameter adjustments; adds front and rear active stabilizer bar systems for active roll suppression of the vehicle; adds front and rear adjustable damping shock absorber systems for real-time adjustment of the shock absorber damping characteristics according to vehicle requirements, wherein the adjustable damping shock absorber can select a product with energy recovery function, which is used to convert the gravitational potential energy generated during the suspension movement into electrical energy storage, thereby reducing the energy consumption of the whole vehicle.

[0061] Embodiment 2

[0062] like Figure 2 As shown, this embodiment provides a bus intelligent suspension system control method, which is applied to the bus intelligent suspension system described in Embodiment 1, and includes:

[0063] Use a multi-sensor network to obtain the current driving status of the bus and the expected characteristics of the road ahead;

[0064] Based on the current driving state of the bus and the expected characteristics of the road ahead, the controller is used to determine the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate and equivalent mean value of vertical vibration at the measuring point position in the next time step;

[0065] Based on the comparison between the roll stability coefficient, longitudinal impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position and the corresponding threshold value at the next time step, the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions are controlled to adjust the above parameters to minimize vibration, keep the vehicle body stable and optimize the vehicle dynamics response.

[0066] Specifically, this embodiment includes:

[0067] Data fusion and state prediction: The controller integrates multi-sensor data to accurately measure the current driving state of the bus (such as body acceleration, lateral acceleration, roll angle, pitch angle, wheel load distribution, etc.), as well as the expected characteristics of the road ahead (such as bumpiness, slope, curve curvature, etc.), and builds an accurate vehicle-road interaction model to provide comprehensive and accurate input information for intelligent decision-making. The so-called vehicle-road interaction model is to build an accurate model of the road ahead that the vehicle is about to arrive, including but not limited to the following four aspects:

[0068] ① Construct a road trajectory model and use the polynomial fitting method to fit the road trajectory into a polynomial

[0069] y=ax 3 +bx 2 +cx+d

[0070] Among them, a, b, c, and d are the coefficients of the polynomial, which are determined by the least square method based on the camera's measured sample data points. After the road trajectory model is established, the curvature ρ of the road and the trajectory radius can be easily calculated.

[0071]

[0072]

[0073] R0≈R 路

[0074] Among them, R0 is the turning radius at the center of mass of the vehicle, which is used to calculate the roll angle and roll impedance of the next time step.

[0075] ② Construct the road longitudinal section curve equation and use the following formula for fitting:

[0076] H=H0+h(1+L / 2D)

[0077] Among them, H represents the elevation of the sample point, H0 is the elevation of the reference point, h is the altitude difference between the sample point and the reference point, L is the distance between the sample point and the reference point, and D is the slope coefficient. After the road longitudinal section curve equation is established, the road conditions ahead can be easily parameterized. According to the road surface height ahead, the height of the air spring and the shock absorber damping are adjusted accordingly to keep the vehicle body posture horizontal and stable at all times, achieving an effect similar to a magic carpet suspension. For example: when there is a pothole ahead, the air spring is inflated, the height of the air spring is raised, and the position of the vehicle body remains unchanged; when there is a bulge ahead, the air spring is deflated, the height of the air spring is lowered, and the position of the vehicle body remains unchanged, thereby achieving the effect of the vehicle body posture always being horizontal.

[0078] ③ Construct the power spectrum density of the road surface roughness ahead and use the following formula for fitting:

[0079] G q (n) = G q (n0)(n / n0) -w

[0080] Among them, n is the spatial frequency, which is the reciprocal of the wavelength, indicating how many wavelengths are included in each meter of length, n0 is the reference spatial frequency, G q (n0) is the pavement power spectrum density value at the reference spatial frequency n0, that is, the pavement roughness coefficient, and W is the frequency index, which is the slope of the oblique line under the double logarithmic coordinates, and it determines the frequency structure of the pavement power spectrum density.

[0081] ④Construct the highway spectral density matrix of the road surface input to the vehicle and use the following formula for processing:

[0082]

[0083] Among them, G ik (n) is the self-amplitude spectrum or mutual-amplitude spectrum of the four wheel positions of the vehicle (i, k = 1, 2, 3, 4 represents the four wheel positions of the vehicle); coh(n) is the coherence function of the wheel tracks of two wheel positions, and L is the wheelbase of the vehicle.

[0084] Model predictive control: Based on the preset vehicle dynamics model and real-time status information, the model predictive control algorithm is used to calculate the optimal suspension parameter settings in multiple future time steps, and guide the suspension system to make forward-looking parameter adjustments to minimize vibration, maintain vehicle stability, and optimize vehicle dynamic response. The so-called model control algorithm is the chip's built-in dynamics simulation software, which establishes a vehicle dynamics model based on vehicle information and obtains the optimal suspension parameters by adjusting the corresponding variables of the model, including but not limited to the following aspects:

[0085] ①Simulate and calculate the expected roll stiffness, roll angle and roll impedance of the next time step.

[0086] Roll stiffness of the vehicle:

[0087] C φ =C φA +C φLB +C φw

[0088] in, is the roll stiffness of the vehicle, The roll stiffness provided by the air spring, The combined roll angle stiffness provided to the suspension guide and front axle, Provides roll stiffness to the stabilizer bar system.

[0089] Roll stiffness provided by air springs:

[0090]

[0091] in, The roll stiffness provided by the air spring, C A is the vertical stiffness of the air spring at the design height, D A is the center distance between the left and right air springs.

[0092] Roll angle stiffness provided by the guide mechanism:

[0093]

[0094] in, The roll stiffness provided by the suspension guide mechanism, C L is the vertical stiffness of the guide arm end point; D L It is the center distance between the end points of the left and right guide arms.

[0095] like Figure 5 As shown, the roll stiffness provided by the stabilizer bar is:

[0096]

[0097] Where: E is the elastic modulus; d is the diameter of the stabilizer bar; I is the moment of inertia of the stabilizer bar section, P is the end force, N; f is the end displacement, mm; other symbols and corresponding dimensions refer to the attached Figure 5 .

[0098] Roll stiffness provided by the front axle:

[0099]

[0100] Where: C φB D is the angular stiffness of the front axle converted to the end point of the guide arm; Lis the center distance of the guide arm seat, that is, the span of the end points of the guide arm; l1 is the length of the guide arm; C B is the torsional stiffness of the front axle between the leaf spring seats.

[0101] The elastic action of the guide arm and the front axle is in series, and their composite angular stiffness is:

[0102]

[0103] Vehicle roll angle:

[0104]

[0105] Where: φ is the roll angle; C φ is the vehicle's roll stiffness; V is the vehicle's forward speed; R0 is the turning radius at the center of mass of the vehicle; g is the acceleration of gravity; G S is the sprung mass; h φ For the roll arm.

[0106] Vehicle roll resistance:

[0107]

[0108] Where: k φ is the roll resistance or roll stability coefficient (in g / Rad), which represents the lateral acceleration (in g) required to produce a unit roll angle.

[0109] The ideal roll stability coefficient k is set within the program φ0 .

[0110] If the roll stability coefficient of the next time step is less than the ideal roll stability coefficient, that is, k φ <k φ0 When the vehicle is in a state of sway, the active stabilizer bar system intervenes and pre-applies force in the opposite direction to the end of the stabilizer bar to increase the roll angle stiffness of the stabilizer bar, thereby improving the roll stability coefficient of the entire vehicle.

[0111] ② Simulate and calculate the pitch stiffness, pitch angle and pitch impedance of the next time step.

[0112] Pitch stiffness:

[0113]

[0114] Among them, C θ is the longitudinal tilt angle stiffness; a1 is the horizontal distance from the neutral plane to the front axle; L is the wheelbase; C1 is the unilateral vertical stiffness of the front suspension; C2 is the unilateral vertical stiffness of the rear suspension.

[0115] Pitch angle:

[0116]

[0117] Where θ is the pitch angle; T S is the inertia force of the sprung mass; C θ is the longitudinal stiffness; h θ is the longitudinal lever arm; G S is the sprung mass.

[0118] Pitch resistance coefficient:

[0119]

[0120] Where: k θ It is the longitudinal resistance coefficient, which expresses the longitudinal force intensity (longitudinal force corresponding to unit sprung weight) required to produce unit longitudinal tilt angle (radian).

[0121] The ideal pitch impedance coefficient k is set within the program θ0 .

[0122] If the pitch impedance coefficient of the next time step is less than the ideal pitch impedance coefficient, that is, k θ <k θ0 When the air spring is in a state of tension, the variable volume air spring auxiliary air chamber intervenes to reduce the auxiliary air chamber volume, increase the stiffness of the air spring assembly, and improve the longitudinal resistance coefficient of the vehicle. At the same time, the adjustable damping shock absorber intervenes to increase the damping of the shock absorber to ensure that the air spring returns to its original position quickly after absorbing energy, preventing excessive continuous vibration (i.e. flutter).

[0123] ③Simulate and calculate the air spring stiffness and frequency deviation of the next time step.

[0124] Air spring rate:

[0125]

[0126] Where: C0 is the stiffness of the air spring at that height; p0 is the relative air pressure of the air spring at that height, measured by the air pressure sensor; A0 is the effective pressure-bearing area of ​​the air spring at that height; V0 is the total volume of the air spring at that height (including the volume of the additional air chamber); p a is standard atmospheric pressure, p a =0.0981≈0.1MPa(N / mm2); m is the variable index: in general, m=1.33 can be taken; is the effective area change rate.

[0127] Deviation value:

[0128]

[0129] Among them: f0 is the natural frequency of the air spring at this height when the relative air pressure is p0, that is, the offset frequency; g is the gravitational acceleration.

[0130] The ideal frequency deviation range f is set within the program 00 And the frequency deviation limit f 01 .

[0131] If the offset frequency value of the next time step exceeds the offset frequency limit, that is, f0>f 01 When f0=f, the variable volume air spring auxiliary air chamber intervenes to adjust the auxiliary air chamber volume and reduce the stiffness of the air spring assembly until f0=f 00 , thereby maintaining the vehicle's driving comfort.

[0132] ④Simulate and calculate the expected understeering gradient and Ackerman rate of the next time step.

[0133] Turning gradient:

[0134]

[0135] Where: K is the understeering coefficient, that is, the understeering gradient; W fl , W fr , W rl , W rr are the sprung masses of the left front, left rear, right front, and right rear wheels respectively; C fl , C fr , C rl , C rr are the cornering stiffness of the left front wheel, left rear wheel, right front wheel and right rear wheel respectively.

[0136]

[0137]

[0138] Ackerman rate:

[0139]

[0140] Where: δ is the tire side slip angle, α0 is the inner wheel turning angle, β0 is the ideal outer wheel turning angle, β is the actual outer wheel turning angle, L 主 is the front axle kingpin center distance, τ is the steering Ackerman rate.

[0141] The ideal understeering gradient value K0 and the allowable limit value K are set within the program. max .

[0142] K needs to satisfy 0<K<K max

[0143] If the understeering gradient value K of the next time step is less than 0, the active stabilizer bar system intervenes to increase the roll stiffness of the front suspension and reduce the roll stiffness of the rear suspension until K=K0, thereby improving the safety of the vehicle and avoiding the side slip or even rollover caused by oversteering. If the understeering gradient value K of the next time step is greater than Kmax , the active stabilizer bar system intervenes to reduce the roll stiffness of the front suspension and increase the roll stiffness of the rear suspension until K=K0; thereby improving the vehicle's maneuverability and avoiding the potential risks of slow vehicle response caused by excessive understeer gradient and vehicle deviation from the expected trajectory.

[0144] The program sets the Ackerman rate limit value τ max and τ min ;

[0145] If the Ackerman rate of the next time step exceeds the allowed limit, that is, τ>τ max Or τ<τ min When the tires are running at high speed, the ECU sends out a command to sound an alarm through the vehicle instrument panel to remind the driver to slow down, thereby preventing abnormal wear of the tires.

[0146] ⑤Simulate and calculate the power spectrum of each wheel position in the next time step.

[0147] G 左前 (n) = G 11 (n)+G 12 (n)+G 13 (n)+G 14 (n)

[0148] G 右前 (n) = G 21 (n)+G 22 (n)+G 23 (n)+G 24 (n)

[0149] G 左后 (n) = G 31 (n)+G 32 (n)+G 33 (n)+G 34 (n)

[0150] G 右后 (n) = G 41 (n)+G 42 (n)+G 43 (n)+G 44 (n)

[0151] Through multiple tests, multiple groups of power spectrum quantities are established (G1(n), G2(n), G3(n)...G n (n)) corresponds to the database of shock absorber damping. 左前 (n), G 右前 (n), G 左后 (n), G 右后 (n) respectively with (G1(n), G2(n), G3(n)...Gn (n)) is compared and the closest database spectrum value is selected, thereby selecting the optimal shock absorber damping data for the four wheel positions in the next time step.

[0152] Online adaptive adjustment: According to the actual driving effect and passenger comfort feedback (such as monitoring through the acceleration sensor of the seat cushion), the control strategy parameters are adjusted in real time to achieve online optimization and personalized adaptation of suspension performance. The so-called passenger comfort feedback sensor can be added to the passenger seat cushion and seat back to measure the vertical acceleration of the seat position over time a(t). By setting the appropriate weighting coefficient, the vertical weighted acceleration over time curve a is obtained. w (t), calculate a w Weighted RMS acceleration of (t):

[0153]

[0154] in: for a w (t) is the root mean square of the weighted acceleration in the Z direction; a w (t) is the time history of weighted acceleration in Z direction; T is the action time.

[0155] Calculate the equivalent mean of the vertical vibration at the measuring point:

[0156]

[0157] Where: L eq It is the equivalent mean value of vertical vibration at the measuring point, in dB;

[0158] The program sets the equivalent mean limit value L of vertical vibration. eqmax and the ideal equivalent mean value of vertical vibration L eq0 ; If L eq >L eqmax , the adjustable damping shock absorber system intervenes to reduce the shock absorber damping until L eq =L eq0 , thereby achieving the purpose of online adjustment.

[0159] Load adaptive compensation: By real-time monitoring of wheel load, the suspension stiffness and damping are automatically adjusted to ensure consistent driving quality under different load conditions.

[0160] Road prediction response: Use road condition perception sensors to sense bumps or obstacles on the road ahead in advance, adjust suspension settings in advance, reduce impact, and improve driving smoothness.

[0161] Active roll suppression: When turning or encountering crosswinds, the active stabilizer bar works together to reduce the body roll, improve vehicle stability and passenger safety. Working principle of the active stabilizer bar: When the vehicle turns, due to inertia, the outer suspension bears a greater weight and will be compressed, while the inner suspension will be stretched due to the reduced weight. At this time, the forces on both ends of the stabilizer bar are uneven, one end moves upward and the other end moves downward, which will cause the stabilizer bar itself to twist. The twisting of the stabilizer bar will generate a reverse torque, which acts on the suspension on both sides to prevent the vehicle from further rolling, thereby reducing the lateral roll angle of the body and maintaining the stability of the vehicle. The active stabilizer bar adds two motors at the two end points. Through the operation of the motors, a torque that suppresses the vehicle's roll is pre-applied. When the vehicle turns, it must first overcome the pre-applied force to achieve the purpose of suppressing the vehicle's roll, thereby improving the vehicle's handling stability and driving safety.

[0162] Intelligent Energy Saving Mode: Under good road conditions and stable vehicle speed, the system automatically optimizes suspension settings, lowers vehicle height to reduce driving resistance, and improves fuel economy or battery life.

[0163] Energy recovery shock absorbers are used to convert the gravitational potential energy generated during suspension movement into stored electrical energy for use by the suspension system itself or on-board electrical equipment, thus achieving energy recycling.

[0164] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bus intelligent suspension system, characterized in that: include: Multi-sensor networks, controllers and adaptive actuators, A multi-sensor network, including a road-condition awareness sensor, mounted above the vehicle's windshield to acquire the expected characteristics of the road ahead; Passenger comfort feedback sensors are installed on the passenger seat cushion and seat back to obtain the curve of the vertical acceleration of the seat position over time; the acceleration sensor and the inclination sensor are both installed near the center of mass of the vehicle. The displacement sensor is used to obtain the position of the vehicle in real time, and the inclination sensor is used to obtain the roll angle and pitch angle of the vehicle in real time; Adaptive actuators, including front and rear active stabilizer bar systems, including front active stabilizer bar systems and rear active stabilizer bar systems, both of which are arranged between two adjacent air springs for active roll suppression of the vehicle; front and rear adjustable damping shock absorber systems, which are installed near the front and rear axle air springs of the vehicle for real-time adjustment of the shock absorber damping characteristics according to vehicle requirements; The controller is used to calculate the optimal suspension parameter settings in multiple future time steps based on the current driving state of the vehicle and the expected characteristics of the road ahead obtained by the multi-sensor network, using a model prediction algorithm, and guide the front and rear active stabilizer bar systems and / or front and rear adjustable damping shock absorber systems to adjust parameters to minimize vibration, maintain vehicle body stability, and optimize vehicle dynamic response.

2. The intelligent suspension system for buses according to claim 1, characterized in that: The adaptive actuator also includes a variable volume air spring auxiliary air chamber which is installed near the air spring and communicated with the inner cavity of the air spring.

3. The intelligent suspension system for buses according to claim 1, characterized in that: The multi-sensor network also includes a height sensor and a pressure sensor installed on the vehicle.

4. A bus intelligent suspension system control method, characterized in that: The intelligent suspension system for a bus as claimed in any one of claims 1 to 3 comprises: Use a multi-sensor network to obtain the current driving status of the bus and the expected characteristics of the road ahead; Based on the current driving state of the bus and the expected characteristics of the road ahead, the controller is used to determine the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate and equivalent mean value of vertical vibration at the measuring point position in the next time step; Based on the comparison between the roll stability coefficient, longitudinal impedance coefficient, offset frequency value, understeer gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position and the corresponding threshold value at the next time step, the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions are controlled to adjust the above parameters to minimize vibration, keep the vehicle body stable and optimize the vehicle dynamics response.

5. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters includes: Determine the roll stiffness provided by the air springs, the combined roll stiffness provided by the suspension guide and front axle, and the roll stiffness provided by the stabilizer bar system; The roll angle stiffness of the next time step is calculated according to the roll angle stiffness provided by the air spring, the composite roll angle stiffness provided by the suspension guide mechanism and the front axle, and the roll angle stiffness provided by the stabilizer bar system; If the roll stability coefficient at the next time step is less than the ideal roll stability coefficient, a force in the opposite direction is pre-applied to the stabilizer bar ends of the front and rear active stabilizer bar systems to increase the roll angle stiffness of the stabilizer bar and thus increase the roll stability coefficient of the entire vehicle.

6. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters also includes: Determine the pitch angle stiffness, sprung mass, and pitch moment arm; Calculate the pitch impedance coefficient for the next time step based on the pitch angle stiffness, sprung mass and pitch moment arm; If the pitch impedance coefficient at the next time step is less than the ideal pitch impedance coefficient, the volume of the variable volume air spring auxiliary air chamber is reduced, and the damping of the front and rear adjustable damping shock absorber systems is increased to increase the pitch impedance coefficient.

7. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters also includes: Determine the effective pressure-bearing area of ​​the air spring at the measuring point height, the rate of change of the effective area, the relative air pressure of the air spring at the height, and the total volume of the air spring at the height; Calculate the frequency deviation value of the next time step according to the effective pressure-bearing area of ​​the air spring at the height of the measuring point, the rate of change of the effective area, the relative air pressure of the air spring at the height, and the total volume of the air spring at the height; If the frequency deviation value of the next time step exceeds the frequency deviation limit, the volume of the auxiliary air chamber of the variable volume air spring is adjusted to reduce the stiffness of the air spring assembly.

8. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters also includes: Determine the sprung mass and cornering stiffness of each tire; According to the sprung mass and cornering stiffness of each tire, the understeer gradient value of the next time step is calculated; If the understeer gradient value at the next time step is less than zero, increase the roll stiffness of the front suspension and reduce the roll stiffness of the rear suspension in the front and rear active stabilizer bar system until the understeer gradient value is equal to the ideal value; if the understeer gradient value at the next time step is greater than the allowable limit of the understeer gradient value, reduce the roll stiffness of the front suspension in the front and rear active stabilizer bar system and increase the roll stiffness of the rear suspension until the understeer gradient value is equal to the ideal value.

9. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters also includes: Determine the tire sideslip angle, inner wheel turning angle, ideal outer wheel turning angle, and actual outer wheel turning angle; Calculate the Ackerman rate of the next time step according to the tire sideslip angle, the inner wheel turning angle, the ideal outer wheel turning angle and the actual outer wheel turning angle; If the Ackerman rate in the next time step exceeds the allowable limit of the Ackerman rate, the vehicle instrument panel will be controlled to sound an alarm.

10. The bus intelligent suspension system control method according to claim 4, characterized in that: Determining the comparison between the roll stability coefficient, pitch impedance coefficient, offset frequency value, understeering gradient value, Ackerman rate or equivalent mean value of vertical vibration at the measuring point position at the next time step and the corresponding threshold value, controlling the front and rear active stabilizer bar systems, front and rear adjustable damping shock absorber systems and / or variable volume air spring auxiliary air chamber actions, and adjusting the above parameters also includes: Determine the curve of vertical acceleration of the passenger seat position over time and calculate the weighted acceleration root mean square; According to the weighted acceleration root mean square, calculate the equivalent mean value of the vertical vibration at the measuring point position in the next time step; If the equivalent mean of the vertical vibration at the measuring point position in the next time step is greater than the equivalent mean limit of the vertical vibration, the damping of the front and rear adjustable damping shock absorber systems is controlled to be reduced until the equivalent mean of the vertical vibration at the measuring point position in the next time step is equal to the equivalent mean limit of the vertical vibration.

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