A disconnected steering trapezoidal Ackerman design optimization method and system

Abstract

The present invention relates to a disconnecting steering trapezoid Ackerman design optimization method and system. According to actual vehicle data, the ideal Ackerman turning angle relationship of the disconnecting steering trapezoid is calculated; the disconnecting steering trapezoid mathematical model is extracted, and the disconnecting steering trapezoid is analytically calculated to obtain the actual Ackerman turning angle relationship; based on the sparrow intelligent optimization algorithm, the sum of the Ackerman errors corresponding to different turning angles is used as the objective function, and the key parameters of the disconnecting steering trapezoid are optimized and designed to obtain the optimal disconnecting steering trapezoid scheme. The disconnecting steering trapezoid calculation and optimization design method provided by the present invention can guide the economic and efficient development of the structural independent suspension, and reduce the abnormal wear of the tires, bringing practical benefits to the car users.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle design, and in particular to a disconnected steering trapezoidal Ackerman design optimization method and system. 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] Ackermann-Steering refers to the steering of the steering wheel (front wheel) on the vehicle chassis through the angle difference between the inner and outer wheels. When turning, the turning radius of the inner wheel will be smaller than that of the outer wheel. This structure can ensure that the centers of the turning radius circles of the four wheels intersect at one point, and all four wheels are in a pure rolling state. On this basis, the Ackermann steering trapezoid refers to the quadrilateral formed by the intersection of the outer points of the left and right steering rods and the left and right wheel kingpins at the height of the cross section of the outer points of the steering rods when viewed from the top view of the vehicle.

[0004] During the vehicle design phase, tire wear needs to be considered. In addition to improving tire compound, structure, pattern and other solutions, the design of the Ackermann steering trapezoid is also one of the main solutions to abnormal tire wear.

[0005] For example, a certain model of vehicle adopts a small-tonnage double wishbone front independent suspension structure, such as Figure 1 As shown in the figure, the shock absorbers and airbags on both sides of the suspension structure are fixed on the bearing seat, and the steering knuckles are driven by two rocker arms in the middle to steer, which can provide a larger aisle space for the vehicle and is widely used in 6-7m micro-circulation buses. The structure forms a disconnected steering trapezoid. For the Ackerman design of this disconnected steering trapezoid, designers currently usually use traditional methods to build ADAMS (automatic analysis software for mechanical system dynamics) kinematics three-dimensional models, perform steering verification calculations, and optimize by modifying some parameters multiple times. Three-dimensional modeling often takes a long time and is inefficient. The optimization method of modifying data multiple times takes a long time and it is difficult to obtain the optimal solution under the constraints. Summary of the invention

[0006] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a disconnected steering trapezoid Ackerman design optimization method and system, by performing analytical calculation on the disconnected steering trapezoid, the corresponding Ackerman relationship analytical expression is obtained, and the minimum Ackerman error is taken as the optimization goal. The key parameters of the steering trapezoid are quickly optimized by the sparrow intelligent optimization algorithm to obtain the most ideal disconnected steering trapezoid solution.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A first aspect of the present invention provides a disconnected steering trapezoidal Ackerman design optimization method, comprising the following steps:

[0009] According to the physical model of the disconnected steering mechanism, the mathematical model of the steering trapezoid is determined;

[0010] According to the mathematical model, the relationship between the ideal steering outer angle and the ideal steering inner angle is determined;

[0011] Based on the determined relationship, the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle are obtained according to the left half steering trapezoid and the right half steering trapezoid in the mathematical model, and the Ackerman relationship of the actual steering outer angle is obtained through post-processing;

[0012] The function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the minimization of the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is used as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel turning angle reaches the maximum are used as constraints, and the optimization algorithm is used to optimize the optimization objective function under the constraints to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

[0013] Further, we turn to the trapezoidal mathematical model, including:

[0014] The knuckle arm AE of the inner steering wheel rotates around the fixed point A by an angle of β, and the landing point of the active point E is E';

[0015] The knuckle arm DH of the outer steering wheel rotates around the fixed point D by an angle α, and the landing point of the active point H is H';

[0016] The steering rocker arm BF of the inner steering wheel rotates by an angle γ around the fixed point B, and the landing point of the active point F is F';

[0017] The steering rocker arm CG of the outer steering wheel rotates around the fixed point G by an angle of γ, and the landing point of the active point G is G';

[0018] The active point E and the active point F are movably connected via a connecting rod EF;

[0019] The active point H is movably connected to the active point G via a connecting rod GH;

[0020] The steering rocker arm BF and the steering rocker arm CG are movably connected by a pull rod so that the two rocker arms can be linked to obtain the same γ angle.

[0021] Furthermore, the mathematical model of the transition to trapezoid also includes:

[0022] The distance between point A and point D is the center distance K of the front axle kingpin, and the distance from the center of the steering wheel to the center of the driving wheel is the wheelbase L; steering rocker arm BF = BF' = CG = CG' = a; steering knuckle arm AE = AE' = DH = DH' = b; the connecting rod between the knuckle arm and the rocker arm EF = E'F' = GH = G'H' = c; the distance between the fixed point of the knuckle arm and the rocker arm AB = CD = d; the initial steering trapezoid base angle ∠ABF = ∠DCG = δ; ∠BAE = ∠CDH = θ; ∠DCH' = σ1; ∠ABE' = σ2;

[0023] Furthermore, according to the mathematical model, the relationship between the ideal steering outer angle and the ideal steering inner angle is determined as shown in the following formula:

[0024]

[0025]

[0026] Among them, α0 is the ideal steering outer angle, β0 is the ideal steering inner angle, β is the steering inner angle, K is the kingpin center distance, and L is the wheelbase.

[0027] Furthermore, the Ackerman relation for the actual turning angle is as follows:

[0028]

[0029] Among them, steering rocker arm BF=BF'=CG=CG'=a; steering knuckle arm AE=AE'=DH=DH'=b; connecting rod EF between knuckle arm and rocker arm=E'F'=GH=G'H'=c; distance between fixed points of knuckle arm and rocker arm AB=CD=d; initial steering trapezoid base angle ∠ABF=∠DCG=δ; ∠BAE=∠CDH=θ, α is the actual steering outer angle, β is the steering inner angle.

[0030] Furthermore, the function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable, specifically:

[0031] Taking the steering knuckle arm b and the steering trapezoid bottom angle θ as the design target, the optimization variable X is X=[x1,x2] T =[b,θ] T , the length of the connecting rod c changes according to the changes of b and θ, and other parameters remain unchanged, represented by variables x1 and x2.

[0032] Furthermore, the connecting rod c is a function of b and θ, as shown in the following formula:

[0033]

[0034] Among them, the steering rocker arm BF=BF'=CG=CG'=a; the distance between the knuckle arm and the rocker arm fixed point AB=CD=d; the initial steering trapezoid base angle ∠ABF=∠DCG=δ.

[0035] Furthermore, the optimization objective function is to minimize the Ackerman error between the actual outer wheel turning angle and the ideal outer wheel turning angle under different inner turning angles, as shown in the following formula:

[0036]

[0037]

[0038] Among them, α is the actual outer wheel angle, α0 is the ideal outer wheel angle, β i is the inner wheel turning angle after discretization, β max is the maximum inner wheel turning angle, ω(β i ) is the weight factor.

[0039] Furthermore, the length range of the steering knuckle arm, the range of the steering trapezoidal bottom angle, and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel turning angle reaches the maximum are used as constraint conditions, as shown in the following formula:

[0040] The length range of the steering knuckle arm b is as shown in the following formula: 0.11K≤b≤0.15K; K is the main pin center distance;

[0041] The angle range of the bottom angle θ of the steering trapezoid is as shown in the following formula: 70deg≤θ≤80deg;

[0042] When the inner wheel turning angle reaches the maximum, the angle λ between the inner wheel steering knuckle arm and the tie rod does not exceed 150 degrees.

[0043] A second aspect of the present invention provides a system for implementing the above method, comprising:

[0044] The model building module is configured to: determine an analytical mathematical model of the steering trapezoid according to a physical model of the disconnecting steering mechanism;

[0045] The relationship calculation module is configured to: determine the relationship between the ideal steering outer angle and the ideal steering inner angle according to the analytical mathematical model;

[0046] The relationship calculation module is further configured to: based on the determined relationship, obtain the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle according to the left half steering trapezoid and the right half steering trapezoid in the analytical mathematical model, and obtain the Ackerman relationship of the actual steering outer angle through post-processing;

[0047] The optimization module is configured as follows: the function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is minimized as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel steering angle reaches the maximum are used as constraints, and the optimization objective function is optimized under the constraints using the optimization algorithm to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

[0048] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps in the above-mentioned disconnected steering trapezoidal Ackerman design optimization method.

[0049] A fourth aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in the above-mentioned disconnected steering trapezoidal Ackerman design optimization method are implemented.

[0050] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0051] According to the vehicle model, the ideal Ackerman angle relationship of the disconnected steering trapezoid is determined; after further analysis of the model, the actual Ackerman angle relationship is obtained, and then through the optimization algorithm, the sum of Ackerman errors corresponding to different angles is used as the objective function to optimize the key parameters of the disconnected steering trapezoid, and the optimal design scheme of the disconnected steering trapezoid can be obtained. Compared with traditional three-dimensional modeling, the mathematical modeling method consumes less time, can improve design efficiency, and can more easily determine the required constraints. Combined with the optimization algorithm executed by the computer, it can more efficiently calculate and optimize the parameters required in the design stage of the disconnected steering trapezoid, thereby more effectively reducing abnormal tire wear and bringing practical benefits to car users. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] 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.

[0053] Figure 1 is a schematic diagram of a small-tonnage double-wishbone front independent suspension provided by one or more embodiments of the present invention;

[0054] Figure 2 is a schematic diagram of a disconnected steering trapezoidal Ackerman design optimization process provided by one or more embodiments of the present invention;

[0055] Figure 3 is a schematic diagram of an analytical mathematical model of a disconnected steering trapezoid provided by one or more embodiments of the present invention;

[0056] Figure 4 is a schematic diagram of the corresponding relationship between the ideal inner and outer wheel turning angles provided by one or more embodiments of the present invention;

[0057] Figure 5 is a schematic diagram of an optimization process flow provided by one or more embodiments of the present invention;

[0058] Figure 6 is a schematic diagram of an Ackerman relationship curve provided by one or more embodiments of the present invention;

[0059] Figure 7 It is a schematic diagram of an iterative process provided by one or more embodiments of the present invention. DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0061] It should be noted that the following detailed descriptions are exemplary and are 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.

[0062] Terminology explanation:

[0063] The disconnected steering trapezoid refers to a vehicle chassis structure in which the tie rod is a disconnected structure rather than an integral structure. Its advantage is that, by cooperating with the independently suspended front wheels, it can ensure that when the wheel on one side bounces up and down, it will not affect the wheel on the other side. Compared with the integral steering trapezoid, the disconnected steering trapezoid has more rod systems and ball heads in its structure, so the structure is more complicated, the manufacturing cost is higher, and it is more difficult to adjust the toe.

[0064] As introduced in the background technology, for the Ackerman design of the disconnected steering trapezoid, current designers usually use the traditional method to build an ADAMS (automatic analysis software for dynamics of mechanical systems) kinematic three-dimensional model, perform steering verification calculations, and optimize by modifying some parameters multiple times. Three-dimensional modeling often takes a long time and is inefficient. The optimization method of modifying data multiple times takes a long time and it is difficult to obtain the optimal solution under the constraints.

[0065] The following embodiment provides a disconnected steering trapezoid Ackerman design optimization method. By performing analytical calculations on the disconnected steering trapezoid, the corresponding Ackerman relationship analytical expression is obtained. With the minimum Ackerman error as the optimization goal, the key parameters of the steering trapezoid are quickly optimized by the Sparrow Intelligent Optimization Algorithm to obtain the most ideal disconnected steering trapezoid scheme. Through theoretical calculations and practical verification, it can be known that the optimization method of this scheme is correct and can obtain the disconnected steering trapezoid parameters with the minimum Ackerman error under constraints, providing a reliable technical method for the size optimization design of the independent suspension of this structure. This method can be used to improve the design level of independent suspension products, improve the work efficiency of designers, and speed up product development. At the same time, it can reduce the abnormal wear of vehicle tires and bring actual benefits to car users.

[0066] Embodiment 1:

[0067] like Figure 1-Figure 7 As shown, a disconnected steering trapezoidal Ackerman design optimization method comprises the following steps:

[0068] According to the physical model of the disconnected steering mechanism, the analytical mathematical model of the steering trapezoid is determined;

[0069] According to the analytical mathematical model, the relationship between the ideal steering outer angle and the ideal steering inner angle is determined;

[0070] Based on the determined relationship, the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle are obtained according to the left half steering trapezoid and the right half steering trapezoid in the analytical mathematical model, and the Ackerman relationship of the actual steering outer angle is obtained through post-processing;

[0071] The function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the minimization of the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is used as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel turning angle reaches the maximum are used as constraints, and the optimization algorithm is used to optimize the optimization objective function under the constraints to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

[0072] This embodiment takes a certain type of vehicle with a small tonnage double wishbone front independent suspension structure as an example to illustrate this solution. Figure 1 As shown, the steering knuckle is driven by two rocker arms in the middle to steer.

[0073] like Figure 2 As shown in the figure, the physical model of the steering mechanism is extracted to obtain the schematic diagram of the analytical mathematical model of the disconnected steering trapezoid. Figure 3The left turn of the turning trapezoid is analyzed, and the right turn is analyzed in the same way.

[0074] The fixed points of the steering knuckle arm are A and D, and the moving points are E and H; the fixed points of the steering rocker arm are B and C, and the moving points are F and G;

[0075] After the steering rocker arms BF and CG rotate rightward (counterclockwise) by an angle of γ around points B and C respectively, points F and G land at points F' and G';

[0076] The knuckle arm DH of the steering outer wheel rotates counterclockwise around point D by an angle α, and the landing point of point H is H';

[0077] The steering knuckle arm AE of the inner steering wheel rotates counterclockwise around point A by an angle of β, and the landing point of point E is E';

[0078] The steering rocker arm BF and the steering rocker arm CG are movably connected by a pull rod so that the two rocker arms can be linked to obtain the same γ angle.

[0079] It is known that the steering rocker arm BF = BF' = CG = CG' = a; the steering knuckle arm AE = AE' = DH = DH' = b; the connecting rod between the knuckle arm and the rocker arm EF = E'F' = GH = G'H' = c; the distance between the knuckle arm and the rocker arm fixed point AB = CD = d; the initial steering trapezoid bottom angle ∠ABF = ∠DCG = δ; ∠BAE = ∠CDH = θ;

[0080] Connect BE' and CH', draw E'P⊥AB through E', with P as the foot of the perpendicular; extend CD, draw H'Q⊥CQ through H', with Q as the foot of the perpendicular;

[0081] ∠DCH'=σ1; ∠ABE'=σ2; ∠G'CH'=φ1; ∠F'BE'=φ2; the front axle kingpin center distance is K and the wheelbase is L.

[0082] The above is an analytical mathematical model of a disconnected steering trapezoid established for a small-tonnage double wishbone front independent suspension structure in a certain type of vehicle. In this embodiment, the wheelbase of a certain micro-circulation bus is L=3500mm, the kingpin center distance K=1521mm; the steering rocker arm of the front independent suspension is BF=BF'=CG=CG'=a=175mm; the steering knuckle arm AE=AE'=DH=DH'=b=165.5mm; the spacing between the knuckle arm and the rocker arm fixed point AB=CD=d=590.5mm; when there is no turning angle, the initial steering trapezoid bottom angle ∠ABF=∠DCG=δ=82.7deg; ∠BAE=∠CDH=θ=85deg; the maximum inner turning angle β max =45deg.

[0083] (1) Calculation of the ideal Ackermann relationship for the inner and outer angles:

[0084] Ignoring the effect of tire side slip, the inner and outer wheel turning angles should be Figure 4 The ideal angle relationship is shown in the figure, so that the tire can roll completely and reduce the wear between the tire and the ground. Let the ideal steering outer angle be α0, then the ideal steering outer angle α0 and the steering inner angle β should satisfy the following formula:

[0085]

[0086] The relationship between the ideal turning outer angle α0 and the ideal turning inner angle β0 is obtained as follows:

[0087]

[0088] In this embodiment, the ideal inner and outer angle relationship curve obtained by the above formula is as follows: Figure 6 The solid curve is shown.

[0089] (2) Analytical calculation of the actual relationship between the steering outer angle and the steering rocker arm angle:

[0090] By analyzing the right half steering trapezoid, according to its structural relationship and the cosine theorem, the angular relationship between the actual steering outer angle α and the rocker arm swing angle γ can be obtained, as shown in the following formula:

[0091]

[0092] (3) Analytical calculation of the actual relationship between the steering inner angle and the steering rocker arm angle:

[0093] By analyzing the left half of the steering trapezoid, according to its structural relationship and the cosine theorem, the angular relationship between the rocker arm swing angle γ and the steering inner angle β can be obtained, as shown in the following formula:

[0094]

[0095] (4) Turning to the actual Ackerman relation analysis and calculation:

[0096] The actual Ackerman relationship of steering can be obtained from the analytical calculation formulas of the actual steering inner angle, steering outer angle and steering rocker arm (Formula 2 and Formula 3):

[0097]

[0098] In this embodiment, the actual inner and outer angle relationship curve before optimization obtained according to the above formula is as follows: Figure 6 The dashed curve is shown.

[0099] (5) Disconnected steering trapezoidal optimization design

[0100] Step I: Optimization variable determination

[0101] According to the convenience of implementing the change of the steering trapezoid, let the design target be the steering knuckle arm b and the bottom angle θ of the steering trapezoid, then the optimization variable X is X=[x1,x2] T =[b,θ] T ;

[0102] The length of the connecting rod c changes according to the changes of b and θ, and other parameters remain unchanged, represented by variables x1 and x2. The connecting rod c is a function of b and θ, as shown in the following formula:

[0103]

[0104] Step II: Objective Function Determination

[0105] The optimization design goal of the disconnected steering trapezoid is to minimize the Ackerman error between the actual outer wheel turning angle α and the ideal outer wheel turning angle α0 at different inner turning angles. The objective function is as follows:

[0106]

[0107] Among them, β i is the inner wheel turning angle after discretization; ω(βi) is the weight factor, let β max is the maximum value of the inner wheel turning angle. According to the frequency of turning angle use, the value range of ω(βi) is as follows:

[0108]

[0109] Step III: Constraint Selection

[0110] The range of the steering knuckle arm length b is shown in the following formula:

[0111] 0.11K≤b≤0.15K;

[0112] The range of the turning trapezoid base angle θ is shown in the following formula:

[0113] 70 degrees ≤ θ ≤ 80 degrees;

[0114] When the inner wheel steering angle reaches the maximum, the angle λ between the inner wheel steering knuckle arm and the tie rod is less than or equal to 150 degrees, as shown in the following formula:

[0115]

[0116] Step IV: This embodiment selects the sparrow intelligent optimization algorithm to optimize the optimization objective function under the constraints. The optimization process is as follows: Figure 5 As shown, the optimized steering knuckle arm b and steering trapezoid bottom angle θ can be obtained.

[0117] By initializing the sparrow population and fitness, the population is divided into discoverers, sentinels and followers and the positions are updated. The fitness of the population is calculated and the global optimal fitness is obtained after sorting. It is compared with the historical optimal fitness. If it is higher than the historical optimal fitness, it is retained, otherwise the historical optimal fitness is used. When the algorithm converges, the optimal sparrow position and optimal fitness are obtained. If it does not converge, it returns to the position update process of the discoverer, sentinel and follower to continue iterating.

[0118] In this embodiment, the rounded steering knuckle arm b and the steering trapezoid bottom angle θ are compared with the scheme before optimization. The comparison results are shown in Table 1. The actual inner and outer turning angle relationship curve after optimization is shown in Figure 6 The dotted line curve is shown in Figure 2. The iterative process is as follows: Figure 7 shown.

[0119] Table 1 Steering knuckle arm b and steering trapezoid bottom angle θ before and after optimization

[0120] plan b / mm θ / deg f Solution before optimization 165 85 59.923 Optimized solution (rounding) 170 80 17.843

[0121] The f in Table 1 is the fitness of the sparrow intelligent optimization algorithm. Figure 6 It can be seen that the optimized solution is the optimal solution under the constraints, and the optimized solution is closer to the ideal Ackerman relationship than the actual Ackerman relationship before optimization. When the vehicle turns, it can better reduce the abnormal wear of the tire and increase its service life.

[0122] In the above process, the disconnected steering trapezoid is analytically calculated to obtain the corresponding Ackerman relationship analytical expression. Taking the minimum Ackerman error as the optimization goal, the key parameters of the steering trapezoid are quickly optimized by the Sparrow Intelligent Optimization Algorithm to obtain the most ideal disconnected steering trapezoid scheme. Through theoretical calculation and practical verification, it can be seen that the optimization method of this scheme is correct and feasible. It can obtain the disconnected steering trapezoid parameters with the minimum Ackerman error under the constraints, and provide a reliable method for the size optimization design of the independent suspension. This method can improve the design level of independent suspension products, improve the work efficiency of designers, and speed up product development. At the same time, it can reduce the abnormal wear of vehicle tires and bring practical benefits to car users.

[0123] Embodiment 2:

[0124] Implementing the above method in a systematic manner includes:

[0125] The model building module is configured to: determine an analytical mathematical model of the steering trapezoid according to a physical model of the disconnecting steering mechanism;

[0126] The relationship calculation module is configured to: determine the relationship between the ideal steering outer angle and the ideal steering inner angle according to the analytical mathematical model;

[0127] The relationship calculation module is further configured to: based on the determined relationship, obtain the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle according to the left half steering trapezoid and the right half steering trapezoid in the analytical mathematical model, and obtain the Ackerman relationship of the actual steering outer angle through post-processing;

[0128] The optimization module is configured as follows: the function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is minimized as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel steering angle reaches the maximum are used as constraints, and the optimization objective function is optimized under the constraints using the optimization algorithm to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

[0129] Embodiment three:

[0130] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps in the disconnected steering trapezoidal Ackerman design optimization method as described in the first embodiment above are implemented.

[0131] Embodiment 4:

[0132] This embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps in the disconnected steering trapezoidal Ackerman design optimization method as described in the first embodiment are implemented.

[0133] The steps involved in the above embodiments 2 to 4 correspond to those in embodiment 1. For the specific implementation, please refer to the relevant description of embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood to include any medium that can store, encode or carry an instruction set for execution by a processor and enable the processor to execute any method in the present invention.

[0134] 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 disconnected steering trapezoidal Ackerman design optimization method, characterized in that: The following steps are involved: According to the physical model of the disconnected steering mechanism, the mathematical model of the steering trapezoid is determined; According to the obtained mathematical model, the relationship between the ideal steering outer angle and the ideal steering inner angle is determined; Based on the obtained relationship, the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle are obtained according to the left half steering trapezoid and the right half steering trapezoid in the mathematical model, and the Ackerman relationship of the actual steering outer angle is obtained through post-processing; The function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the minimization of the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is used as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel turning angle reaches the maximum are used as constraints, and the optimization algorithm is used to optimize the optimization objective function under the constraints to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

2. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: The mathematical model of the turning trapezoid includes: The knuckle arm AE of the inner steering wheel rotates around the fixed point A by an angle of β, and the landing point of the active point E is E'; The knuckle arm DH of the outer steering wheel rotates around the fixed point D by an angle α, and the landing point of the active point H is H'; The steering rocker arm BF of the inner steering wheel rotates by an angle γ around the fixed point B, and the landing point of the active point F is F'; The steering rocker arm CG of the outer steering wheel rotates around the fixed point G by an angle of γ, and the landing point of the active point G is G'; The active point E and the active point F are movably connected via a connecting rod EF; The active point H is movably connected to the active point G via a connecting rod GH; The steering rocker arm BF and the steering rocker arm CG are movably connected by a pull rod, and the two rocker arms are linked to produce the same γ angle.

3. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 2, characterized in that: The mathematical model of the turning trapezoid also includes: The distance between point A and point D is the front axle kingpin center distance K, and the distance from the steering wheel center to the driving wheel center is the wheelbase L; the steering rocker arm BF = BF' = CG = CG' = a; the steering knuckle arm AE = AE' = DH = DH' = b; the connecting rod EF between the knuckle arm and the rocker arm EF = E'F' = GH = G'H' = c; the distance between the fixed points of the knuckle arm and the rocker arm AB = CD = d; the initial steering trapezoid base angle ∠ABF = ∠DCG = δ; ∠BAE = ∠CDH = θ.

4. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: According to the mathematical model, the relationship between the ideal steering outer angle and the ideal steering inner angle is determined as shown in the following formula: Among them, α0 is the ideal steering outer angle, β0 is the ideal steering inner angle, β is the steering inner angle, K is the kingpin center distance, and L is the wheelbase.

5. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: The Ackerman relation for the actual turning angle is shown below: Among them, steering rocker arm BF=BF'=CG=CG'=a; steering knuckle arm AE=AE'=DH=DH'=b; connecting rod EF between knuckle arm and rocker arm=E'F'=GH=G'H'=c; distance between fixed points of knuckle arm and rocker arm AB=CD=d; initial steering trapezoid base angle ∠ABF=∠DCG=δ; ∠BAE=∠CDH=θ, α is the actual steering outer angle, β is the steering inner angle.

6. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: The function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable, specifically: Taking the steering knuckle arm b and the steering trapezoid bottom angle θ as the design target, the optimization variable X is X=[x1,x2] T =[b,θ] T The length of the connecting rod c changes according to the changes in b and θ, and is represented by variables x1 and x2.

7. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 6, characterized in that: The connecting rod c is a function of the steering knuckle arm b and the bottom angle θ of the steering trapezoid, as shown in the following formula: Among them, the steering rocker arm BF=BF'=CG=CG'=a; the distance between the fixed point of the knuckle arm and the rocker arm AB=CD=d; the initial steering trapezoid base angle ∠ABF=∠DCG=δ, and x1 and x2 are variables.

8. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: The optimization objective function is to minimize the Ackerman error between the actual outer wheel angle and the ideal outer wheel angle at different inner turning angles, as shown in the following formula: Among them, α is the actual outer wheel angle, α0 is the ideal outer wheel angle, β i is the inner wheel turning angle after discretization, β max is the maximum inner wheel turning angle, ω(β i ) is the weight factor.

9. A disconnected steering trapezoidal Ackerman design optimization method as claimed in claim 1, characterized in that: The length range of the steering knuckle arm, the range of the steering trapezoidal bottom angle, and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel turning angle reaches the maximum are used as constraints, as shown in the following formula: The length range of the steering knuckle arm b is as shown in the following formula: 0.11K≤b≤0.15K; K is the main pin center distance; The angle range of the bottom angle θ of the steering trapezoid is as shown in the following formula: 70deg≤θ≤80deg; When the inner wheel turning angle reaches the maximum, the angle λ between the inner wheel steering knuckle arm and the tie rod does not exceed 150 degrees.

10. A disconnected steering trapezoidal Ackerman design optimization system, characterized in that: include: The system data acquisition module is configured to: obtain the security activity information of the system to be monitored and convert it into a traceability diagram; The model building module is configured to: determine an analytical mathematical model of the steering trapezoid according to a physical model of the disconnecting steering mechanism; The relationship calculation module is configured to: determine the relationship between the ideal steering outer angle and the ideal steering inner angle according to the analytical mathematical model; The relationship calculation module is further configured to: based on the determined relationship, obtain the angle relationship between the actual steering outer angle and the rocker arm swing angle, and the angle relationship between the rocker arm swing angle and the steering inner angle according to the left half steering trapezoid and the right half steering trapezoid in the analytical mathematical model, and obtain the Ackerman relationship of the actual steering outer angle through post-processing; The optimization module is configured as follows: the function of the length of the steering knuckle arm and the bottom angle of the steering trapezoid is used as the optimization variable; the Ackerman error between the actual outer wheel steering angle and the ideal outer wheel steering angle under different inner turning angles is minimized as the optimization objective function; the length range of the steering knuckle arm, the steering trapezoid bottom angle range and the angle range between the inner wheel steering knuckle arm and the tie rod when the inner wheel steering angle reaches the maximum are used as constraints, and the optimization objective function is optimized under the constraints using the optimization algorithm to obtain the optimal length parameters of the steering knuckle arm and the angle parameters of the steering trapezoid bottom angle.

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