A hydrocarbon active suspension control system based on a three-axle vehicle

Abstract

The application discloses a kind of oil-gas active suspension control systems based on three-axis vehicle, including driving information detection unit, comprehensive evaluation index calculation unit, oil-gas active suspension control mode selection unit, oil-gas active suspension execution unit.Wherein, driving information detection unit is used to obtain vehicle driving speed, initial detection red primary color pixel coordinate value, initial detection green primary color pixel coordinate value, initial detection blue primary color pixel coordinate value;Comprehensive evaluation index calculation unit is used to calculate road identification accuracy factor, active safety factor, road feature extraction factor, to obtain comprehensive evaluation index;Oil-gas active suspension control mode selection unit includes front axle active control mode, middle axle active control mode and rear axle active control mode;Oil-gas active suspension execution unit adjusts the oil-gas active suspension actuator output damping force of different axle according to different control mode.

Description

Technical Field

[0001] This invention relates to an active hydropneumatic suspension control system for a three-axle vehicle. Background Technology

[0002] Faced with changing operating environments for engineering vehicles, ensuring driving safety, handling stability, ride comfort, and operational economy are crucial issues affecting vehicle reliability. Traditional leaf spring suspension systems are characterized by heavy weight, high stiffness, poor comfort, low load-bearing capacity, and poor cushioning. For driving safety, handling stability, ride comfort, and operational economy, hydropneumatic active suspension control needs to consider road surface recognition accuracy, active safety, and road feature extraction factors. Therefore, effectively ensuring vehicle smoothness and comfort during driving has become a pressing technical problem for the applicant. To address these issues, this invention proposes a hydropneumatic active suspension control system based on a three-axle vehicle. Summary of the Invention

[0003] The purpose of this invention is to provide an active hydropneumatic suspension control system based on a three-axle vehicle to solve the problems encountered in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an active oil-gas suspension control system based on a three-axle vehicle, comprising a driving information detection unit, a comprehensive evaluation index calculation unit, an active oil-gas suspension control mode selection unit, and an active oil-gas suspension execution unit.

[0005] The driving information detection unit is used to obtain the vehicle speed, the initial detection of the red primary color pixel coordinates R(x,y,z), the initial detection of the green primary color pixel coordinates G(x,y,z), and the initial detection of the blue primary color pixel coordinates B(x,y,z).

[0006] The comprehensive evaluation index calculation unit calculates the road surface recognition accuracy factor J1, the active safety factor J2, and the road surface feature extraction factor J3 to obtain the comprehensive evaluation index J; wherein the road surface recognition accuracy factor J1 depends on the influence coefficient k of the number of radars. a The influence coefficient of the number of cameras, k b The influence coefficient k of the sensor signal transmission speed c The active safety factor J2 depends on the active safety system influence coefficient k. d and the driver's proactive prediction of the risk factor k e Among them, the driver actively anticipates the risk factors k e Depends on the influence coefficient k of familiarity with the driving road f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k hThe road surface feature extraction factor J3 depends on the CCD camera image processing influence coefficient k. h A generalized sign function is designed to determine the flatness, convexity, and depression of the road surface based on the difference between the coordinate value z of the flat road surface and the vertical reference value z0, thereby obtaining the CCD camera image processing influence coefficient k. h The function relationship between the grayscale image pixel value Q(x,y,z) and the initial detected red primary color pixel coordinates R(x,y,z), the initial detected green primary color pixel coordinates G(x,y,z), the initial detected blue primary color pixel coordinates B(x,y,z), and the adjustment factor k. Q ;

[0007] The oil-gas active suspension control mode selection unit includes a front axle active control mode, a center axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the center axle active control mode, and the control strength of the center axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor thresholds γ1, center axle control factor thresholds γ2, and rear axle control factor thresholds γ3, where 0 < γ3 < γ2 < γ1 < 1. When the comprehensive evaluation index J satisfies γ1 ≤ J < 1, the oil-gas active suspension execution unit executes the front axle active control mode; when the comprehensive evaluation index J satisfies γ2 ≤ J < γ1, the oil-gas active suspension execution unit executes the center axle active control mode; when the comprehensive evaluation index J satisfies γ3 ≤ J < γ2, the oil-gas active suspension execution unit executes the rear axle active control mode; when the comprehensive evaluation index J satisfies 0 ≤ J < γ3, the oil-gas active suspension execution unit does not perform any operation.

[0008] When the hydropneumatic active suspension actuator executes the front axle active control mode, it calculates the output damping force F of the front axle hydropneumatic active suspension actuator. Z1 Its value depends on the output damping force F of the front axle hydropneumatic active suspension throttle orifice. J1 Weighting coefficient K of the output damping force of the front axle hydropneumatic active suspension throttle orifice J1 Weighted coefficient K of piston friction force in front axle hydropneumatic active suspension f1 Friction force F in the center area of ​​the piston of the front axle hydropneumatic active suspension f11 Friction F in the linear zone of the front axle hydropneumatic active suspension piston f12 Friction F between the front axle hydropneumatic active suspension piston and the nonlinear region f13 A front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode. The front axle differential ratio factor η1 depends on the front axle adjustment response factor K1 and the front axle differential ratio coefficient η. e1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The front axle differential ratio coefficient η e1 The first judgment factor λ for the front axle is designed based on the distance *a* from the vehicle's center of gravity to the front axle, the distance *b* from the vehicle's center of gravity to the center axle, the distance *c* from the vehicle's center of gravity to the rear axle, the diameter *d1* of the front axle hydraulic hose, and the length *l1* of the front axle hydraulic hose. 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 <15%, the vehicle will be adjusted according to the magnitude of the front axle differential ratio factor η1;

[0009] When the hydropneumatic active suspension actuator executes the central axle active control mode, it calculates the output damping force F of the central axle hydropneumatic active suspension actuator. Z2 Its value depends on the output damping force F of the central axis oil-gas active suspension throttle orifice. J2 Weighting coefficient K of the output damping force of the central axis oil-gas active suspension throttle orifice J2 Weighted coefficient F of piston friction force in central axle hydropneumatic active suspension f21 Friction force F in the center area of ​​the piston of the central axis oil-pneumatic active suspension f21 Friction F in the linear zone of the piston of the central axis oil-gas active suspension f22 Friction F in the nonlinear region of the piston of the central axis oil-gas active suspension f23 A center axle difference ratio factor η2 is designed to evaluate the degree of oil-gas active suspension control in the center axle active control mode. The center axle difference ratio factor η2 depends on the center axle adjustment response factor K2 and the center axle difference ratio coefficient η. e2 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The central axis difference ratio coefficient η e2 The first decision factor λ for the central axle is designed based on the following distances: a (distance from the vehicle's center of gravity to the central axle), b (distance from the vehicle's center of gravity to the central axle), c (distance from the vehicle's center of gravity to the rear axle), d2 (diameter of the central axle hydraulic hose), and l2 (length of the central axle hydraulic hose). 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 <18%, the vehicle will be adjusted according to the size of the center axle difference ratio factor η2;

[0010] When the hydropneumatic active suspension actuator executes the rear axle active control mode, it calculates the output damping force F of the rear axle hydropneumatic active suspension actuator. Z3Its value depends on the output damping force F of the throttle orifice of the rear axle hydropneumatic active suspension. J3 The weighted coefficient K of the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 Weighted coefficient K for piston friction force of rear axle hydropneumatic active suspension f3 Friction force F in the center area of ​​the piston of the rear axle hydropneumatic active suspension f31 Friction F in the linear zone of the rear axle hydropneumatic active suspension piston f32 Friction F between the piston in the nonlinear region of the rear axle hydropneumatic active suspension f33 A rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode. The rear axle differential ratio factor η3 depends on the rear axle adjustment response factor K3 and the rear axle differential ratio coefficient η. e3 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The rear axle differential ratio coefficient η e3 The first judgment factor λ for the rear axle is designed based on the following distances: a from the vehicle's center of gravity to the rear axle, b from the vehicle's center of gravity to the center axle, c from the vehicle's center of gravity to the rear axle, d3 of the diameter of the rear axle hydraulic hose, and l3 of the rear axle hydraulic hose. 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 <20%, the vehicle will be adjusted according to the size of the rear axle difference ratio factor η3.

[0011] Specifically, it includes the following:

[0012] S1. The comprehensive evaluation index calculation unit can calculate the road surface identification accuracy factor according to the following formula:

[0013]

[0014] Where w1, w2, w3, and w4 are weighting coefficients, and w1 + w2 + w3 + w4 = 1, k a The radar number influence coefficient depends on the number of radars installed in the vehicle. When the number of radars installed in the vehicle does not exceed 2, k a =0.3, when the number of radars installed in the vehicle exceeds 2 but does not exceed 6, k a =0.6, when the number of radars installed in the vehicle exceeds 6, k a =0.9, k b The influence coefficient for the number of cameras depends on the total number of cameras installed in the vehicle. When the total number of cameras installed in the vehicle does not exceed 4, k b=0.4, when the number of cameras installed in the vehicle exceeds 4 but does not exceed 8, k b =0.7, when the number of cameras installed in the vehicle exceeds 8, k b =0.85, k c The coefficient representing the influence of sensor signal transmission speed;

[0015] S2. The comprehensive evaluation index calculation unit can calculate the active safety factor according to the following formula:

[0016]

[0017] Where w5 and w6 are weighting coefficients, and w5 + w6 = 1, k d The active safety system impact coefficient depends on the number of active safety systems installed in the vehicle. These active safety systems include adaptive cruise control, lane departure warning, blind spot monitoring, anti-lock braking system (ABS), electronic stability control, collision mitigation braking, automatic emergency braking, lane keeping assist, blind spot detection, speed assist, forward collision warning, driver alert, and brake assist. When the number of active safety systems installed in the vehicle does not exceed four, k... d =0.8, when the number of active safety systems installed in the vehicle exceeds 4 but does not exceed 7, k d =0.88, when the number of active safety systems installed in the vehicle exceeds 7, k d =0.95, k e The value of the risk factor that allows the driver to proactively anticipate danger depends on the road familiarity factor k. f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k h Its expression is:

[0018]

[0019] Where α1, α2, and α3 are weighting coefficients, and α1 + α2 + α3 = 1, when the number of times the driver travels on the road does not exceed 2, k f =0.3, when the number of times the driver travels on the road exceeds 2 but does not exceed 4, k f =0.6, when the driver repeats the road more than 4 times, k f =0.8, when a driver's driving experience is less than 1 year, the driver is defined as a novice driver, k g =0.45. When a driver's driving experience exceeds 1 year but does not exceed 3 years, the driver is defined as a transitional driver, k g=0.65, when a driver has more than 3 years of driving experience, the driver is defined as an experienced driver, k g =0.85;

[0020] S3. The comprehensive evaluation index calculation unit can calculate the road feature extraction factor according to the following formula:

[0021]

[0022] Where, k h Let be the CCD camera image processing influence coefficient. Its value depends on the initial detection red primary color pixel coordinates R(x,y,z), the initial detection green primary color pixel coordinates G(x,y,z), the initial detection blue primary color pixel coordinates B(x,y,z), and the grayscale image pixel values ​​Q(x,y,z). Its expression is:

[0023] Q(x,y,z)=k Q ||0.367R(x,y,z)+0.438G(x,y,z)+0.195B(x,y,z)||,

[0024] Where, k Q This is an adjustment factor, whose value is dynamically adjusted according to changes in the adhesion coefficient, and its range is from 1.8 to 3.9.

[0025] Design a generalized sign function with coordinate value z as the independent variable. If (z-z0) > 12mm, the CCD camera identifies the road surface feature as a convex feature; if (z-z0) < -12mm, the CCD camera identifies the road surface feature as a concave feature; and if -12 < (z-z0) < 12mm, the CCD camera identifies the road surface feature as flat. Calculate k based on the identified road surface feature. h Its expression is:

[0026]

[0027] Where z0 is the vertical reference value of the coordinate value z of the flat road surface.

[0028] The comprehensive evaluation index calculation unit can calculate the comprehensive evaluation index according to the following formula:

[0029]

[0030] Among them, Q1, Q2, and Q3 are the weighted values ​​calculated for individual indicators.

[0031] The active suspension control mode selection unit includes a front axle active control mode, a middle axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the middle axle active control mode, and the control strength of the middle axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor threshold γ1, middle axle control factor threshold γ2, and rear axle control factor threshold γ3, where 0 < γ3 < γ2 < γ1 < 1.

[0032] When the comprehensive evaluation index J satisfies γ1≤J<1, the hydropneumatic active suspension actuator executes the front axle active control mode, and the expression for the output damping force of the front axle hydropneumatic active suspension actuator is as follows:

[0033]

[0034] Among them, F J1 K is the output damping force of the throttle orifice of the front axle hydropneumatic active suspension. J1 K is the weighting coefficient for the output damping force of the throttle orifice of the front axle hydropneumatic active suspension. f1 F is the weighting coefficient for piston friction in the front axle hydropneumatic active suspension. f11 For the friction force in the center area of ​​the piston of the front axle hydropneumatic active suspension, F f12 For the frictional force in the linear zone of the front axle hydropneumatic active suspension piston, F f13 For the nonlinear region friction force of the front axle hydropneumatic active suspension piston;

[0035] The front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode, and its expression is as follows:

[0036]

[0037] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K1 is the pressure loss coefficient of the active air-pneumatic suspension when hydraulic fluid flows out of the accumulator, and η is the front axle adjustment response factor. e1 The front axle differential ratio coefficient is expressed as follows:

[0038]

[0039] Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d1 is the diameter of the front axle hydraulic oil rubber hose, and l1 is the length of the front axle hydraulic oil rubber hose.

[0040] Design the first judgment factor λ for the front axle 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 If the difference is less than 15%, the vehicle will be adjusted accordingly based on the front axle difference ratio factor η1, as follows:

[0041] The current axis difference ratio factor satisfies λ 12 ≤η1≤λ 11 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; the current axle difference ratio factor satisfied η1>λ 11 Or 0≤η1<λ 12 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t1s, the control system re-determined whether η1 satisfied λ. 12 ≤η1≤λ 11 If we judge λ again 12 ≤η1≤λ 11 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η1 > λ 11 Or 0≤η1<λ 12 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0042] When the comprehensive evaluation index J satisfies γ2≤J<γ1, the oil-gas active suspension actuator executes the central axle active control mode, and the expression for the output damping force of the central axle oil-gas active suspension actuator is as follows:

[0043]

[0044] Among them, F J2 For the damping force output from the throttle orifice of the central axis hydropneumatic active suspension, K J2 K is the weighting coefficient for the output damping force of the throttle orifice of the central axis hydropneumatic active suspension. f2 F is the weighting coefficient for piston friction in the central axle hydropneumatic active suspension. f21 For the friction force in the center area of ​​the piston of the central axle hydropneumatic active suspension, F f22 For the linear zone friction force of the piston in the central axle hydropneumatic active suspension, F f23 For the nonlinear region friction force of the piston in the central axis oil-gas active suspension;

[0045] The axle difference ratio factor η2 is designed to evaluate the degree of hydropneumatic active suspension control in the axle active control mode. Its expression is as follows:

[0046]

[0047] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K2 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K2 is the central axle adjustment response factor, and η is the hydraulic fluid pressure loss coefficient when the hydraulic fluid flows out of the accumulator. e2 The central axis difference ratio coefficient is expressed as follows:

[0048]

[0049] Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d2 is the diameter of the center axle hydraulic oil rubber hose, and l2 is the length of the center axle hydraulic oil rubber hose.

[0050] The first judgment factor λ in the design axis 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 If the difference is less than 18%, the vehicle will be adjusted accordingly based on the axle difference ratio factor η2, as follows:

[0051] When the axis difference ratio factor satisfies λ 22 ≤η2≤λ 21 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; when the axle difference ratio factor satisfies η2>λ 21 Or 0 ≤ η2 < λ 22 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the central axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t2 seconds, the control system re-determined whether η2 satisfied λ. 22 ≤η2≤λ 21 If we judge λ again 22 ≤η2≤λ 21 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η2 > λ 21 Or 0 ≤ η2 < λ 22 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0052] When the comprehensive evaluation index J satisfies γ3≤J<γ2, the oil-gas active suspension actuator executes the rear axle active control mode, and the expression for the output damping force of the rear axle oil-gas active suspension actuator is as follows:

[0053]

[0054] Among them, F J3 K is the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 K is the weighting coefficient for the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. f3 F is the weighting coefficient for the piston friction force of the rear axle hydropneumatic active suspension. f31 For the friction force in the center area of ​​the piston of the rear axle hydropneumatic active suspension, F f32 For the frictional force in the linear zone of the rear axle hydropneumatic active suspension piston, F f33 For the nonlinear region friction force of the piston in the rear axle hydropneumatic active suspension;

[0055] The rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode, and its expression is as follows:

[0056]

[0057] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K3 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K3 is the rear axle adjustment response factor, and η is the pressure loss coefficient of the hydropneumatic active suspension. e3 The rear axle differential ratio coefficient is expressed as follows:

[0058]

[0059] Where a is the distance from the vehicle's center of gravity to the rear axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d3 is the diameter of the rear axle hydraulic oil rubber hose, and l3 is the length of the rear axle hydraulic oil rubber hose.

[0060] The first judgment factor λ for designing the rear axle 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 If the ratio is less than 20%, the vehicle will be adjusted accordingly based on the rear axle difference ratio factor η3, as follows:

[0061] When the rear axle difference ratio factor satisfies λ32 ≤η3≤λ 31 At that time, it was determined that the effect of the hydropneumatic active suspension actuator in executing the rear axle active control mode was good, the hydropneumatic active suspension control was still executing normally, and the actuator output damping force was still output normally; when the rear axle differential ratio factor satisfies η3>λ 31 Or 0≤η3<λ 32 At that time, it was determined that the effect of the oil-gas active suspension actuator executing the rear axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t3s, the control system re-determined whether η3 satisfied λ. 32 ≤η3≤λ 31 If we judge λ again 32 ≤η3≤λ 31 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η3 > λ 31 Or 0≤η3<λ 32 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0062] When the comprehensive evaluation index J satisfies 0≤J<γ3, the oil-gas active suspension actuator does not perform its function.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0064] 1. A hydropneumatic active suspension control system based on a three-axle vehicle obtains a comprehensive evaluation index based on road surface recognition accuracy factors, active safety factors, and road surface feature extraction factors.

[0065] 2. The control modes of the present invention are front axle active control mode, mid-axle active control mode and rear axle control mode. The control strength of the front axle active control mode is higher than that of the mid-axle active control mode, and the control strength of the mid-axle active control mode is higher than that of the rear axle control mode. The control strength of the control mode is described by designing front axle control factor threshold, mid-axle control factor threshold and rear axle control factor threshold.

[0066] 3. Based on different control modes, calculate the output damping force of the hydropneumatic active suspension actuators for different axles. By designing differential ratio factors for different axles, evaluate the degree of hydropneumatic active suspension control under different control modes. Adjust the vehicle according to the corresponding rules based on the magnitude of the differential ratio factors for different axles. Attached Figure Description

[0067] The present invention will be further described below with reference to the accompanying drawings:

[0068] Figure 1 This is a framework diagram of an active hydropneumatic suspension control system based on a three-axle vehicle proposed in this invention. Detailed Implementation

[0069] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0070] like Figure 1 As shown, the present invention is an active hydropneumatic suspension control system based on a three-axle vehicle, including a driving information detection unit, a comprehensive evaluation index calculation unit, an active hydropneumatic suspension control mode selection unit, and an active hydropneumatic suspension execution unit.

[0071] The driving information detection unit is used to obtain the vehicle speed, the initial detection of the red primary color pixel coordinates R(x,y,z), the initial detection of the green primary color pixel coordinates G(x,y,z), and the initial detection of the blue primary color pixel coordinates B(x,y,z).

[0072] The comprehensive evaluation index calculation unit calculates the road surface recognition accuracy factor J1, the active safety factor J2, and the road surface feature extraction factor J3 to obtain the comprehensive evaluation index J; wherein the road surface recognition accuracy factor J1 depends on the influence coefficient k of the number of radars. a The influence coefficient of the number of cameras, k b The influence coefficient k of the sensor signal transmission speed c The active safety factor J2 depends on the active safety system influence coefficient k. d and the driver's proactive prediction of the risk factor k e Among them, the driver actively anticipates the risk factors k e Depends on the influence coefficient k of familiarity with the driving road f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k h The road surface feature extraction factor J3 depends on the CCD camera image processing influence coefficient k. h A generalized sign function is designed to determine the flatness, convexity, and depression of the road surface based on the difference between the coordinate value z of the flat road surface and the vertical reference value z0, thereby obtaining the CCD camera image processing influence coefficient k. h The function relationship between the grayscale image pixel value Q(x,y,z) and the initial detected red primary color pixel coordinates R(x,y,z), the initial detected green primary color pixel coordinates G(x,y,z), the initial detected blue primary color pixel coordinates B(x,y,z), and the adjustment factor k. Q ;

[0073] The oil-gas active suspension control mode selection unit includes a front axle active control mode, a center axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the center axle active control mode, and the control strength of the center axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor thresholds γ1, center axle control factor thresholds γ2, and rear axle control factor thresholds γ3, where 0 < γ3 < γ2 < γ1 < 1. When the comprehensive evaluation index J satisfies γ1 ≤ J < 1, the oil-gas active suspension execution unit executes the front axle active control mode; when the comprehensive evaluation index J satisfies γ2 ≤ J < γ1, the oil-gas active suspension execution unit executes the center axle active control mode; when the comprehensive evaluation index J satisfies γ3 ≤ J < γ2, the oil-gas active suspension execution unit executes the rear axle active control mode; when the comprehensive evaluation index J satisfies 0 ≤ J < γ3, the oil-gas active suspension execution unit does not perform any operation.

[0074] When the hydropneumatic active suspension actuator executes the front axle active control mode, it calculates the output damping force F of the front axle hydropneumatic active suspension actuator. Z1 Its value depends on the output damping force F of the front axle hydropneumatic active suspension throttle orifice. J1 Weighting coefficient K of the output damping force of the front axle hydropneumatic active suspension throttle orifice J1 Weighted coefficient K of piston friction force in front axle hydropneumatic active suspension f1 Friction force F in the center area of ​​the piston of the front axle hydropneumatic active suspension f11 Friction F in the linear zone of the front axle hydropneumatic active suspension piston f12 Friction F between the front axle hydropneumatic active suspension piston and the nonlinear region f13 A front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode. The front axle differential ratio factor η1 depends on the front axle adjustment response factor K1 and the front axle differential ratio coefficient η. e1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The front axle differential ratio coefficient η e1 The first judgment factor λ for the front axle is designed based on the distance *a* from the vehicle's center of gravity to the front axle, the distance *b* from the vehicle's center of gravity to the center axle, the distance *c* from the vehicle's center of gravity to the rear axle, the diameter *d1* of the front axle hydraulic hose, and the length *l1* of the front axle hydraulic hose. 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 <15%, the vehicle will be adjusted according to the magnitude of the front axle differential ratio factor η1;

[0075] When the hydropneumatic active suspension actuator executes the central axle active control mode, it calculates the output damping force F of the central axle hydropneumatic active suspension actuator. Z2 Its value depends on the output damping force F of the central axis oil-gas active suspension throttle orifice. J2 Weighting coefficient K of the output damping force of the central axis oil-gas active suspension throttle orifice J2 Weighted coefficient F of piston friction force in central axle hydropneumatic active suspension f21 Friction force F in the center area of ​​the piston of the central axis oil-pneumatic active suspension f21 Friction F in the linear zone of the piston of the central axis oil-gas active suspension f22 Friction F in the nonlinear region of the piston of the central axis oil-gas active suspension f23 A center axle difference ratio factor η2 is designed to evaluate the degree of oil-gas active suspension control in the center axle active control mode. The center axle difference ratio factor η2 depends on the center axle adjustment response factor K2 and the center axle difference ratio coefficient η. e2 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The central axis difference ratio coefficient η e2 The first decision factor λ for the central axle is designed based on the following distances: a (distance from the vehicle's center of gravity to the central axle), b (distance from the vehicle's center of gravity to the central axle), c (distance from the vehicle's center of gravity to the rear axle), d2 (diameter of the central axle hydraulic hose), and l2 (length of the central axle hydraulic hose). 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 <18%, the vehicle will be adjusted according to the size of the center axle difference ratio factor η2;

[0076] When the hydropneumatic active suspension actuator executes the rear axle active control mode, it calculates the output damping force F of the rear axle hydropneumatic active suspension actuator. Z3 Its value depends on the output damping force F of the throttle orifice of the rear axle hydropneumatic active suspension. J3 The weighted coefficient K of the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 Weighted coefficient K for piston friction force of rear axle hydropneumatic active suspension f3 Friction force F in the center area of ​​the piston of the rear axle hydropneumatic active suspension f31 Friction F in the linear zone of the rear axle hydropneumatic active suspension piston f32 Friction F between the piston in the nonlinear region of the rear axle hydropneumatic active suspension f33 A rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode. The rear axle differential ratio factor η3 depends on the rear axle adjustment response factor K3 and the rear axle differential ratio coefficient η. e3The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The rear axle differential ratio coefficient η e3 The first judgment factor λ for the rear axle is designed based on the following distances: a from the vehicle's center of gravity to the rear axle, b from the vehicle's center of gravity to the center axle, c from the vehicle's center of gravity to the rear axle, d3 of the diameter of the rear axle hydraulic hose, and l3 of the rear axle hydraulic hose. 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 <20%, the vehicle will be adjusted according to the size of the rear axle difference ratio factor η3.

[0077] Specifically, it includes the following:

[0078] S1. The comprehensive evaluation index calculation unit can calculate the road surface identification accuracy factor according to the following formula:

[0079]

[0080] Where w1, w2, w3, and w4 are weighting coefficients, and w1 + w2 + w3 + w4 = 1, k a The radar number influence coefficient depends on the number of radars installed in the vehicle. When the number of radars installed in the vehicle does not exceed 2, k a =0.3, when the number of radars installed in the vehicle exceeds 2 but does not exceed 6, k a =0.6, when the number of radars installed in the vehicle exceeds 6, k a =0.9, k b The influence coefficient for the number of cameras depends on the total number of cameras installed in the vehicle. When the total number of cameras installed in the vehicle does not exceed 4, k b =0.4, when the number of cameras installed in the vehicle exceeds 4 but does not exceed 8, k b =0.7, when the number of cameras installed in the vehicle exceeds 8, k b =0.85, k c The coefficient representing the influence of sensor signal transmission speed;

[0081] S2. The comprehensive evaluation index calculation unit can calculate the active safety factor according to the following formula:

[0082]

[0083] Where w5 and w6 are weighting coefficients, and w5 + w6 = 1, k dThe active safety system impact coefficient depends on the number of active safety systems installed in the vehicle. These active safety systems include adaptive cruise control, lane departure warning, blind spot monitoring, anti-lock braking system (ABS), electronic stability control, collision mitigation braking, automatic emergency braking, lane keeping assist, blind spot detection, speed assist, forward collision warning, driver alert, and brake assist. When the number of active safety systems installed in the vehicle does not exceed four, k... d =0.8, when the number of active safety systems installed in the vehicle exceeds 4 but does not exceed 7, k d =0.88, when the number of active safety systems installed in the vehicle exceeds 7, k d =0.95, k e The value of the risk factor that allows the driver to proactively anticipate danger depends on the road familiarity factor k. f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k h Its expression is:

[0084]

[0085] Where α1, α2, and α3 are weighting coefficients, and α1 + α2 + α3 = 1, when the number of times the driver travels on the road does not exceed 2, k f =0.3, when the number of times the driver travels on the road exceeds 2 but does not exceed 4, k f =0.6, when the driver repeats the road more than 4 times, k f =0.8, when a driver's driving experience is less than 1 year, the driver is defined as a novice driver, k g =0.45. When a driver's driving experience exceeds 1 year but does not exceed 3 years, the driver is defined as a transitional driver, k g =0.65, when a driver has more than 3 years of driving experience, the driver is defined as an experienced driver, k g =0.85;

[0086] S3. The comprehensive evaluation index calculation unit can calculate the road feature extraction factor according to the following formula:

[0087]

[0088] Where, k h Let be the CCD camera image processing influence coefficient. Its value depends on the initial detection red primary color pixel coordinates R(x,y,z), the initial detection green primary color pixel coordinates G(x,y,z), the initial detection blue primary color pixel coordinates B(x,y,z), and the grayscale image pixel values ​​Q(x,y,z). Its expression is:

[0089] Q(x,y,z)=k Q ||0.367R(x,y,z)+0.438G(x,y,z)+0.195B(x,y,z)||,

[0090] Where, k Q This is an adjustment factor, whose value is dynamically adjusted according to changes in the adhesion coefficient, and its range is from 1.8 to 3.9.

[0091] Design a generalized sign function with coordinate value z as the independent variable. If (z-z0) > 12mm, the CCD camera identifies the road surface feature as a convex feature; if (z-z0) < -12mm, the CCD camera identifies the road surface feature as a concave feature; and if -12 < (z-z0) < 12mm, the CCD camera identifies the road surface feature as flat. Calculate k based on the identified road surface feature. h Its expression is:

[0092]

[0093] Where z0 is the vertical reference value of the coordinate value z of the flat road surface.

[0094] The comprehensive evaluation index calculation unit can calculate the comprehensive evaluation index according to the following formula:

[0095]

[0096] Among them, Q1, Q2, and Q3 are the weighted values ​​calculated for individual indicators.

[0097] The active suspension control mode selection unit includes a front axle active control mode, a middle axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the middle axle active control mode, and the control strength of the middle axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor threshold γ1, middle axle control factor threshold γ2, and rear axle control factor threshold γ3, where 0 < γ3 < γ2 < γ1 < 1.

[0098] When the comprehensive evaluation index J satisfies γ1≤J<1, the hydropneumatic active suspension actuator executes the front axle active control mode, and the expression for the output damping force of the front axle hydropneumatic active suspension actuator is as follows:

[0099]

[0100] Among them, F J1 K is the output damping force of the throttle orifice of the front axle hydropneumatic active suspension. J1 K is the weighting coefficient for the output damping force of the throttle orifice of the front axle hydropneumatic active suspension. f1F is the weighting coefficient for piston friction in the front axle hydropneumatic active suspension. f11 For the friction force in the center area of ​​the piston of the front axle hydropneumatic active suspension, F f12 For the frictional force in the linear zone of the front axle hydropneumatic active suspension piston, F f13 For the nonlinear region friction force of the front axle hydropneumatic active suspension piston;

[0101] The front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode, and its expression is as follows:

[0102]

[0103] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K1 is the pressure loss coefficient of the active air-pneumatic suspension when hydraulic fluid flows out of the accumulator, and η is the front axle adjustment response factor. e1 The front axle differential ratio coefficient is expressed as follows:

[0104]

[0105] Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d1 is the diameter of the front axle hydraulic oil rubber hose, and l1 is the length of the front axle hydraulic oil rubber hose.

[0106] Design the first judgment factor λ for the front axle 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 If the difference is less than 15%, the vehicle will be adjusted accordingly based on the front axle difference ratio factor η1, as follows:

[0107] The current axis difference ratio factor satisfies λ 12 ≤η1≤λ 11 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; the current axle difference ratio factor satisfied η1>λ 11 Or 0≤η1<λ 12 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t1s, the control system re-determined whether η1 satisfied λ. 12 ≤η1≤λ11 If we judge λ again 12 ≤η1≤λ 11 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η1 > λ 11 Or 0≤η1<λ 12 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0108] When the comprehensive evaluation index J satisfies γ2≤J<γ1, the oil-gas active suspension actuator executes the central axle active control mode, and the expression for the output damping force of the central axle oil-gas active suspension actuator is as follows:

[0109]

[0110] Among them, F J2 For the damping force output from the throttle orifice of the central axis hydropneumatic active suspension, K J2 K is the weighting coefficient for the output damping force of the throttle orifice of the central axis hydropneumatic active suspension. f2 F is the weighting coefficient for piston friction in the central axle hydropneumatic active suspension. f21 For the friction force in the center area of ​​the piston of the central axle hydropneumatic active suspension, F f22 For the linear zone friction force of the piston in the central axle hydropneumatic active suspension, F f23 For the nonlinear region friction force of the piston in the central axis oil-gas active suspension;

[0111] The axle difference ratio factor η2 is designed to evaluate the degree of hydropneumatic active suspension control in the axle active control mode. Its expression is as follows:

[0112]

[0113] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K2 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K2 is the central axle adjustment response factor, and η is the hydraulic fluid pressure loss coefficient when the hydraulic fluid flows out of the accumulator. e2 The central axis difference ratio coefficient is expressed as follows:

[0114]

[0115] Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d2 is the diameter of the center axle hydraulic oil rubber hose, and l2 is the length of the center axle hydraulic oil rubber hose.

[0116] The first judgment factor λ in the design axis 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 If the difference is less than 18%, the vehicle will be adjusted accordingly based on the axle difference ratio factor η2, as follows:

[0117] When the axis difference ratio factor satisfies λ 22 ≤η2≤λ 21 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; when the axle difference ratio factor satisfies η2>λ 21 Or 0 ≤ η2 < λ 22 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the central axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t2 seconds, the control system re-determined whether η2 satisfied λ. 22 ≤η2≤λ 21 If we judge λ again 22 ≤η2≤λ 21 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η2 > λ 21 Or 0 ≤ η2 < λ 22 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0118] When the comprehensive evaluation index J satisfies γ3≤J<γ2, the oil-gas active suspension actuator executes the rear axle active control mode, and the expression for the output damping force of the rear axle oil-gas active suspension actuator is as follows:

[0119]

[0120] Among them, F J3 K is the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 K is the weighting coefficient for the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. f3 F is the weighting coefficient for the piston friction force of the rear axle hydropneumatic active suspension. f31 For the friction force in the center area of ​​the piston of the rear axle hydropneumatic active suspension, F f32 For the frictional force in the linear zone of the rear axle hydropneumatic active suspension piston, F f33 For the nonlinear region friction force of the piston in the rear axle hydropneumatic active suspension;

[0121] The rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode, and its expression is as follows:

[0122]

[0123] Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the oil-gas suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K3 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K3 is the rear axle adjustment response factor, and η is the pressure loss coefficient of the hydropneumatic active suspension. e3 The rear axle differential ratio coefficient is expressed as follows:

[0124]

[0125] Where a is the distance from the vehicle's center of gravity to the rear axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d3 is the diameter of the rear axle hydraulic oil rubber hose, and l3 is the length of the rear axle hydraulic oil rubber hose.

[0126] The first judgment factor λ for designing the rear axle 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 If the ratio is less than 20%, the vehicle will be adjusted accordingly based on the rear axle difference ratio factor η3, as follows:

[0127] When the rear axle difference ratio factor satisfies λ 32 ≤η3≤λ 31 At that time, it was determined that the effect of the hydropneumatic active suspension actuator in executing the rear axle active control mode was good, the hydropneumatic active suspension control was still executing normally, and the actuator output damping force was still output normally; when the rear axle differential ratio factor satisfies η3>λ 31 Or 0≤η3<λ 32 At that time, it was determined that the effect of the oil-gas active suspension actuator executing the rear axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t3s, the control system re-determined whether η3 satisfied λ. 32 ≤η3≤λ 31 If we judge λ again 32 ≤η3≤λ 31 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η3 > λ 31 Or 0≤η3<λ 32 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

[0128] When the comprehensive evaluation index J satisfies 0≤J<γ3, the oil-gas active suspension actuator does not perform its function.

Claims

1. A hydropneumatic active suspension control system for a three-axle vehicle, characterized in that, Includes the following: It includes a driving information detection unit, a comprehensive evaluation index calculation unit, an oil-gas active suspension control mode selection unit, and an oil-gas active suspension execution unit; The driving information detection unit is used to obtain the vehicle speed, the initial detection of the red primary color pixel coordinates R(x,y,z), the initial detection of the green primary color pixel coordinates G(x,y,z), and the initial detection of the blue primary color pixel coordinates B(x,y,z). The comprehensive evaluation index calculation unit calculates the road surface recognition accuracy factor J1, the active safety factor J2, and the road surface feature extraction factor J3 to obtain the comprehensive evaluation index J; wherein the road surface recognition accuracy factor J1 depends on the influence coefficient k of the number of radars. a The influence coefficient of the number of cameras, k b The influence coefficient k of the sensor signal transmission speed c The active safety factor J2 depends on the active safety system influence coefficient k. d and the driver's proactive prediction of hazard impact factor k e Among them, the driver actively anticipates the risk factors k e Depends on the influence coefficient k of familiarity with the driving road f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k h The road surface feature extraction factor J3 depends on the CCD camera image processing influence coefficient k. h A generalized sign function is designed to determine the flatness, convexity, and depression of the road surface based on the difference between the coordinate value z of the flat road surface and the vertical reference value z0, thereby obtaining the CCD camera image processing influence coefficient k. h The function relationship between the grayscale image pixel value Q(x,y,z) and the initial detected red primary color pixel coordinates R(x,y,z), the initial detected green primary color pixel coordinates G(x,y,z), the initial detected blue primary color pixel coordinates B(x,y,z), and the adjustment factor k. Q ; The active suspension control mode selection unit includes a front axle active control mode, a center axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the center axle active control mode, and the control strength of the center axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor thresholds γ1, center axle control factor thresholds γ2, and rear axle control factor thresholds γ3, where 0 < γ3 < γ2 < γ1 < 1. When the comprehensive evaluation index J satisfies γ1 ≤ J < 1, the oil-gas active suspension actuator executes the front axle active control mode; when the comprehensive evaluation index J satisfies γ2 ≤ J < γ1, the oil-gas active suspension actuator executes the center axle active control mode; when the comprehensive evaluation index J satisfies γ3 ≤ J < γ2, the oil-gas active suspension actuator executes the rear axle active control mode; when the comprehensive evaluation index J satisfies 0 ≤ J < γ3, the oil-gas active suspension actuator does not perform any operation. When the hydropneumatic active suspension actuator executes the front axle active control mode, it calculates the output damping force F of the front axle hydropneumatic active suspension actuator. Z1 Its value depends on the output damping force F of the front axle hydropneumatic active suspension throttle orifice. J1 Weighting coefficient K of the output damping force of the front axle hydropneumatic active suspension throttle orifice J1 Weighted coefficient K of piston friction force in front axle hydropneumatic active suspension f1 Friction force F in the center area of ​​the piston of the front axle hydropneumatic active suspension f11 Friction F in the linear zone of the front axle hydropneumatic active suspension piston f12 Friction F between the front axle hydropneumatic active suspension piston and the nonlinear region f13 A front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode. The front axle differential ratio factor η1 depends on the front axle adjustment response factor K1 and the front axle differential ratio coefficient η. e1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The front axle differential ratio coefficient η e1 The first judgment factor λ for the front axle is designed based on the distance 'a' from the vehicle's center of gravity to the front axle, the distance 'b' from the vehicle's center of gravity to the center axle, the distance 'c' from the vehicle's center of gravity to the rear axle, the diameter 'd1' of the front axle hydraulic hose, and the length 'l1' of the front axle hydraulic hose. 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 <15%, the vehicle will be adjusted according to the magnitude of the front axle differential ratio factor η1; When the hydropneumatic active suspension actuator executes the central axle active control mode, it calculates the output damping force F of the central axle hydropneumatic active suspension actuator. Z2 Its value depends on the output damping force F of the central axis oil-gas active suspension throttle orifice. J2 Weighting coefficient K of the output damping force of the central axis oil-gas active suspension throttle orifice J2 Weighted coefficient F of piston friction force in central axle hydropneumatic active suspension f21 Friction force F in the center area of ​​the piston of the central axis oil-pneumatic active suspension f21 Friction F in the linear zone of the piston of the central axis oil-gas active suspension f22 Friction F in the nonlinear region of the piston of the central axis oil-gas active suspension f23 A center axle difference ratio factor η2 is designed to evaluate the degree of oil-gas active suspension control in the center axle active control mode. The center axle difference ratio factor η2 depends on the center axle adjustment response factor K2 and the center axle difference ratio coefficient η. e2 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The central axis difference ratio coefficient η e2 The first decision factor λ for the central axle is designed based on the following distances: a (distance from the vehicle's center of gravity to the central axle), b (distance from the vehicle's center of gravity to the central axle), c (distance from the vehicle's center of gravity to the rear axle), d2 (diameter of the central axle hydraulic hose), and l2 (length of the central axle hydraulic hose). 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 <18%, the vehicle will be adjusted according to the size of the center axle difference ratio factor η2; When the hydropneumatic active suspension actuator executes the rear axle active control mode, it calculates the output damping force F of the rear axle hydropneumatic active suspension actuator. Z3 Its value depends on the output damping force F of the throttle orifice of the rear axle hydropneumatic active suspension. J3 The weighted coefficient K of the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 Weighted coefficient K for piston friction force of rear axle hydropneumatic active suspension f3 Friction force F in the center area of ​​the piston of the rear axle hydropneumatic active suspension f31 Friction F in the linear zone of the rear axle hydropneumatic active suspension piston f32 Friction F between the piston in the nonlinear region of the rear axle hydropneumatic active suspension f33 A rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode. The rear axle differential ratio factor η3 depends on the rear axle adjustment response factor K3 and the rear axle differential ratio coefficient η. e3 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s1 The pressure loss coefficient ξ of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator. s2 The rear axle differential ratio coefficient η e3 The first judgment factor λ for the rear axle is designed based on the following distances: a from the vehicle's center of gravity to the rear axle, b from the vehicle's center of gravity to the center axle, c from the vehicle's center of gravity to the rear axle, d3 of the diameter of the rear axle hydraulic hose, and l3 of the rear axle hydraulic hose. 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 <20%, the vehicle will be adjusted according to the size of the rear axle difference ratio factor η3.

2. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: Specifically, it includes the following: S1. The comprehensive evaluation index calculation unit can calculate the road surface identification accuracy factor according to the following formula: Where w1, w2, w3, and w4 are weighting coefficients, and w1 + w2 + w3 + w4 = 1, k a The radar number influence coefficient depends on the number of radars installed in the vehicle. When the number of radars installed in the vehicle does not exceed 2, k a =0.3, when the number of radars installed in the vehicle exceeds 2 but does not exceed 6, k a =0.6, when the number of radars installed in the vehicle exceeds 6, k a =0.9, k b The influence coefficient for the number of cameras depends on the total number of cameras installed in the vehicle. When the total number of cameras installed in the vehicle does not exceed 4, k b =0.4, when the number of cameras installed in the vehicle exceeds 4 but does not exceed 8, k b =0.7, when the number of cameras installed in the vehicle exceeds 8, k b =0.85, k c The coefficient representing the influence of sensor signal transmission speed; S2. The comprehensive evaluation index calculation unit can calculate the active safety factor according to the following formula: Where w5 and w6 are weighting coefficients, and w5 + w6 = 1, k d The active safety system impact coefficient depends on the number of active safety systems installed in the vehicle. These active safety systems include adaptive cruise control, lane departure warning, blind spot monitoring, anti-lock braking system (ABS), electronic stability control, collision mitigation braking, automatic emergency braking, lane keeping assist, blind spot detection, speed assist, forward collision warning, driver alert, and brake assist. When the number of active safety systems installed in the vehicle does not exceed four, k... d =0.8, when the number of active safety systems installed in the vehicle exceeds 4 but does not exceed 7, k d =0.88, when the number of active safety systems installed in the vehicle exceeds 7, k d =0.95, k e The value of the risk factor that allows the driver to proactively anticipate danger depends on the road familiarity factor k. f Driver's driving experience influence coefficient k g And the driver's predicted risk impact coefficient k h Its expression is: Where α1, α2, and α3 are weighting coefficients, and α1 + α2 + α3 = 1, when the number of times the driver travels on the road does not exceed 2, k f =0.3, when the number of times the driver travels on the road exceeds 2 but does not exceed 4, k f =0.6, when the driver repeats the road more than 4 times, k f =0.8, when a driver's driving experience is less than 1 year, the driver is defined as a novice driver, k g =0.

45. When a driver's driving experience exceeds 1 year but does not exceed 3 years, the driver is defined as a transitional driver, k g =0.65, when a driver has more than 3 years of driving experience, the driver is defined as an experienced driver, k g =0.85; S3. The comprehensive evaluation index calculation unit can calculate the road feature extraction factor according to the following formula: Where, k h Let be the CCD camera image processing influence coefficient. Its value depends on the initial detection red primary color pixel coordinates R(x,y,z), the initial detection green primary color pixel coordinates G(x,y,z), the initial detection blue primary color pixel coordinates B(x,y,z), and the grayscale image pixel values ​​Q(x,y,z). Its expression is: Q(x,y,z)=k Q ||0.367R(x,y,z)+0.438G(x,y,z)+0.195B(x,y,z)||, Where, k Q This is an adjustment factor, whose value is dynamically adjusted according to changes in the adhesion coefficient, and its range is from 1.8 to 3.

9. Design a generalized sign function with coordinate value z as the independent variable. If (z-z0) > 12mm, the CCD camera identifies the road surface feature as a convex feature; if (z-z0) < -12mm, the CCD camera identifies the road surface feature as a concave feature; and if -12 < (z-z0) < 12mm, the CCD camera identifies the road surface feature as flat. Calculate k based on the identified road surface feature. h Its expression is: Where z0 is the vertical reference value of the coordinate value z of the flat road surface.

3. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: The comprehensive evaluation index calculation unit can calculate the comprehensive evaluation index according to the following formula: Among them, Q1, Q2, and Q3 are the weighted values ​​calculated for individual indicators.

4. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: The active suspension control mode selection unit includes a front axle active control mode, a middle axle active control mode, and a rear axle active control mode. The control strength of the front axle active control mode is higher than that of the middle axle active control mode, and the control strength of the middle axle active control mode is higher than that of the rear axle active control mode. The control strength of the control mode is described by designing front axle control factor threshold γ1, middle axle control factor threshold γ2, and rear axle control factor threshold γ3, where 0 < γ3 < γ2 < γ1 < 1.

5. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: When the comprehensive evaluation index J satisfies γ1≤J<1, the hydropneumatic active suspension actuator executes the front axle active control mode, and the expression for the output damping force of the front axle hydropneumatic active suspension actuator is as follows: Among them, F J1 K is the output damping force of the throttle orifice of the front axle hydropneumatic active suspension. J1 K is the weighting coefficient for the output damping force of the front axle hydropneumatic active suspension throttle orifice. f1 F is the weighting coefficient for piston friction in the front axle hydropneumatic active suspension. f11 For the friction force in the center area of ​​the piston of the front axle hydropneumatic active suspension, F f12 For the frictional force in the linear zone of the front axle hydropneumatic active suspension piston, F f13 For the nonlinear region friction force of the front axle hydropneumatic active suspension piston; The front axle differential ratio factor η1 is designed to evaluate the degree of hydropneumatic active suspension control in the front axle active control mode, and its expression is as follows: Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the hydropneumatic suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K1 is the pressure loss coefficient of the active air-pneumatic suspension when hydraulic fluid flows out of the accumulator, and η is the front axle adjustment response factor. e1 The front axle differential ratio coefficient is expressed as follows: Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d1 is the diameter of the front axle hydraulic oil rubber hose, and l1 is the length of the front axle hydraulic oil rubber hose. Design the first judgment factor λ for the front axle 11 The second judgment factor λ of the front axle 12 The front axle active control is re-judged at time t1, and 0 < λ. 12 <λ 11 If the difference is less than 15%, the vehicle will be adjusted accordingly based on the front axle difference ratio factor η1, as follows: The current axis difference ratio factor satisfies λ 12 ≤η1≤λ 11 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; the current axle difference ratio factor satisfied η1>λ 11 Or 0≤η1<λ 12 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the front axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t1s, the control system re-determined whether η1 satisfied λ. 12 ≤η1≤λ 11 If we judge λ again 12 ≤η1≤λ 11 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η1 > λ 11 Or 0≤η1<λ 12 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

6. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: When the comprehensive evaluation index J satisfies γ2≤J<γ1, the oil-gas active suspension actuator executes the central axle active control mode, and the expression for the output damping force of the central axle oil-gas active suspension actuator is as follows: Among them, F J2 For the damping force output from the throttle orifice of the central axis hydropneumatic active suspension, K J2 K is the weighting coefficient for the output damping force of the throttle orifice of the central axis hydropneumatic active suspension. f2 F is the weighting coefficient for piston friction in the central axle hydropneumatic active suspension. f21 For the friction force in the center area of ​​the piston of the central axle hydropneumatic active suspension, F f22 For the linear zone friction force of the piston in the central axle hydropneumatic active suspension, F f23 For the nonlinear region friction force of the piston in the central axis oil-gas active suspension; The axle difference ratio factor η2 is designed to evaluate the degree of hydropneumatic active suspension control in the axle active control mode. Its expression is as follows: Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the hydropneumatic suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K2 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K2 is the central axle adjustment response factor, and η is the hydraulic fluid pressure loss coefficient when the hydraulic fluid flows out of the accumulator. e2 The central axis difference ratio coefficient is expressed as follows: Where a is the distance from the vehicle's center of gravity to the front axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d2 is the diameter of the center axle hydraulic oil rubber hose, and l2 is the length of the center axle hydraulic oil rubber hose. The first judgment factor λ in the design axis 21 The second judgment factor λ of the central axis 22 The central axis active control is then re-judged at time t2, and 0 < λ. 22 <λ 21 If the difference is less than 18%, the vehicle will be adjusted accordingly based on the axle difference ratio factor η2, as follows: When the axis difference ratio factor satisfies λ 22 ≤η2≤λ 21 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the axle active control mode was good, the oil-gas active suspension control was still executing normally, and the actuator output damping force was still output normally; when the axle difference ratio factor satisfies η2>λ 21 Or 0 ≤ η2 < λ 22 At that time, it was determined that the effect of the oil-gas active suspension actuator in executing the central axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t2s, the control system re-determined whether η2 satisfied λ. 22 ≤η2≤λ 21 If we judge λ again 22 ≤η2≤λ 21 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η2 > λ 21 Or 0 ≤ η2 < λ 22 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

7. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: When the comprehensive evaluation index J satisfies γ3≤J<γ2, the oil-gas active suspension actuator executes the rear axle active control mode, and the expression for the output damping force of the rear axle oil-gas active suspension actuator is as follows: Among them, F J3 K is the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. J3 K is the weighting coefficient for the output damping force of the throttle orifice of the rear axle hydropneumatic active suspension. f3 F is the weighting coefficient for the piston friction force of the rear axle hydropneumatic active suspension. f31 For the friction force in the center area of ​​the piston of the rear axle hydropneumatic active suspension, F f32 For the frictional force in the linear zone of the rear axle hydropneumatic active suspension piston, F f33 For the nonlinear region friction force of the piston in the rear axle hydropneumatic active suspension; The rear axle differential ratio factor η3 is designed to evaluate the degree of hydropneumatic active suspension control in the rear axle active control mode, and its expression is as follows: Where v is the piston rod speed, ρ is the hydraulic fluid density, and P s For the pressure loss of the hydropneumatic suspension, P w For external air pressure, ξ s1 ξ is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid enters the accumulator. s2 K3 is the pressure loss coefficient of the hydropneumatic active suspension when hydraulic fluid flows out of the accumulator, K3 is the rear axle adjustment response factor, and η is the pressure loss coefficient of the hydropneumatic active suspension. e3 The rear axle differential ratio coefficient is expressed as follows: Where a is the distance from the vehicle's center of gravity to the rear axle, b is the distance from the vehicle's center of gravity to the center axle, c is the distance from the vehicle's center of gravity to the rear axle, d is the piston rod diameter, D is the piston cylinder inner diameter, d3 is the diameter of the rear axle hydraulic oil rubber hose, and l3 is the length of the rear axle hydraulic oil rubber hose. The first judgment factor λ for designing the rear axle 31 Second judgment factor λ of the rear axle 32 The rear axle active control is re-judged at time t3, and 0 < λ. 32 <λ 31 If the ratio is less than 20%, the vehicle will be adjusted accordingly based on the rear axle difference ratio factor η3, as follows: When the rear axle difference ratio factor satisfies λ 32 ≤η3≤λ 31 At that time, it was determined that the effect of the hydropneumatic active suspension actuator in executing the rear axle active control mode was good, the hydropneumatic active suspension control was still executing normally, and the actuator output damping force was still output normally; when the rear axle differential ratio factor satisfies η3>λ 31 Or 0 ≤ η3 < λ 32 At that time, it was determined that the effect of the oil-gas active suspension actuator executing the rear axle active control mode was poor, and the oil-gas active suspension control was temporarily executed normally. After t3s, the control system re-determined whether η3 satisfied λ. 32 ≤η3≤λ 31 If we judge λ again 32 ≤η3≤λ 31 If the active suspension control is still functioning normally, the actuator output damping force will still be output normally. If it is determined again that η3 > λ 31 Or 0≤η3<λ 32 If so, it is necessary to recalculate and then adjust the control of the oil-gas active suspension and the output damping force of the suspension actuator.

8. The hydropneumatic active suspension control system based on a three-axle vehicle according to claim 1, characterized in that: When the comprehensive evaluation index J satisfies 0≤J<γ3, the oil-gas active suspension actuator does not perform its function.

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