CN102222144A - Optimization method of arrangement of chassis drive shaft of minibus - Google Patents

Abstract

The invention discloses an optimization method of the arrangement of a chassis drive shaft of a minibus. In the method, an included angle theta 1 of a cardan at the input end of the drive shaft and an included angle theta 2 of a cardan at the output end of the drive shaft are used as optimization parameters, the minimum equivalent residual angle of the cardans of the drive shaft is used as a target function, and the optimization process adopts complex algorithms. The worst point of the complexes is searched, replaced and iterated to complete optimization calculation. The method disclosed by the invention is helpful to solving the multi-parameter optimization problem of the arrangement of the drive shaft, increasing the design efficiency and accuracy, and reducing the faults.

Description

Little automobile chassis transmission shaft optimizing method for disposing

Technical field

The present invention relates to little automobile chassis transmission shaft design field, be specifically related to a kind of little automobile chassis transmission shaft optimizing method for disposing.

Background technology

Generally all there is the situation that chassis transmission shaft vibration is big, noise is high in little the automobile of selling on the existing market, thereby influence riding comfort in the car, the layout that mainly is the chassis transmission shaft of tracing it to its cause involves many areas, relation factor is many, calculated amount is big and very loaded down with trivial details.Therefore go back the method and system of neither one maturation at present, can under the situation of input few parameters, calculate the prioritization scheme that the chassis transmission shaft is arranged, thereby improve the design efficiency and the analysis precision of chassis transmission shaft.

Summary of the invention

In view of this, the invention provides a kind of little automobile chassis transmission shaft optimizing method for disposing, can adopt simple method to solve transmission shaft layout optimization problem, thereby improve the layout design efficient and the analysis precision of chassis transmission shaft.

This scheme is achieved in that the angle theta with transmission shaft input end universal joint ₁Angle theta with transmission shaft output terminal universal joint ₂For optimizing parameter, be objective function with transmission shaft universal joint equivalent residual error angle minimum, optimizing process takes the complex algorithm to carry out.Described complex is carried out worst point search, replace and iterate, finally finish computation optimization.

According to above technical scheme as seen, using the present invention is that objective function, optimizing process take the complex algorithm can help to solve the multi-parameters optimization problem that transmission shaft is arranged by correct design with transmission shaft universal joint equivalent residual error angle minimum, improved design efficiency and precision, reduced transmission shaft and arranged error.Use the present invention can help to solve the multi-parameters optimization problem that transmission shaft is arranged, improved design efficiency and precision, reduced error.

Description of drawings

Fig. 1 is the process flow diagram of transmission shaft optimizing method for disposing of the present invention.

Fig. 2 is a user interface of the present invention.

Fig. 3 is the complex method process flow diagram.

Embodiment

Below in conjunction with the accompanying drawing embodiment that develops simultaneously, describe the present invention.

The whether reasonable transmission performance that directly influences power train of transmission shaft design arrangement, and arrange that improper meeting increases unnecessary additional dynamic load to power train, increase vibration and noise, and can cause power train not run well and early stage the damage.When adopting Z font shown in Figure 2 or two Cardan shaft arrangements of W type, for reaching at the uniform velocity transmission, or make with the interrelate non-uniform movement of quality of transmission shaft as far as possible for a short time, should make the transmission non-uniformity U of these two universal joints ₁And U ₂Differential closely zero, and

$U_1=\frac{{\sin }^2{\mathrm{\&theta;}}_1}{\cos {\mathrm{\&theta;}}_1},$ ${\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000071266050000021.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{{\sin }^2{\mathrm{\&theta;}}_2}{\cos {\mathrm{\&theta;}}_2}$

So

$U_1-{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000071266050000021.png"\; state="\{\{state\}\}">U</figure-callout>}}_2=\frac{{\sin }^2{\mathrm{\&theta;}}_1}{\cos {\mathrm{\&theta;}}_1}-\frac{{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000071266050000021.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&theta;}}_2}{\cos {\mathrm{\&theta;}}_2}---\left(1\right)$

Work as θ ₁And θ ₂Hour, sin θ ₁≈ θ ₁, sin θ ₂≈ θ ₂, cos θ ₁≈ 1, cos θ ₂≈ 1.Therefore, formula (1) can be reduced to

$U_1-{\mathrm{<figure-callout\; id="2"\; label="U"\; filenames="HDA0000071266050000021.png"\; state="\{\{state\}\}">U</figure-callout>}}_2\&ap;{\mathrm{\&theta;}}_1^2-{\mathrm{\&theta;}}_2^2---\left(2\right)$

Defining residual error angle β again is

$\mathrm{\&beta;}=\sqrt{|{\mathrm{\&theta;}}_1^2-{\mathrm{\&theta;}}_2^2|}---\left(3\right)$

So will make with the interrelate non-uniform movement of quality of transmission shaft as far as possible for a short time, make residual error angle β minimum as long as guarantee as far as possible.

According to the automobile engineering design experiences, determine to optimize constraint condition in addition.

Therefore, the present invention is according to transmission shaft, back axle kinematics and kinetic theory, a kind of little automobile chassis transmission shaft optimizing method for disposing is provided, and this method adopts complex method to optimize the angle of transmission shaft input end universal joint and the angle of transmission shaft output terminal universal joint; The optimization parameter of complex method is the angle theta of transmission shaft input end universal joint ₁Angle theta with transmission shaft output terminal universal joint ₂, and with total system transmission shaft angle residual error β minimum as optimization aim, θ ₁And θ ₂Be respectively the angle of transmission shaft input end universal joint and output terminal;

Objective function and constraint condition that complex method is used are respectively:

Objective function: min $z=\sqrt{|{\mathrm{\&theta;}}_1^2-{\mathrm{\&theta;}}_2^2|}---\left(4\right)$

Constraint condition:

|θ ₁-θ ₂|≤6 ⁰

ε ₃≤500rad/s ²；

ω ₃、ε ₃≥0；θ ₁，θ ₂≥0。(5)

Wherein,

ω ₃, ε ₃Be respectively the angular displacement of transmission shaft output terminal, angular velocity and angular acceleration, substitution such as lower drive shaft motion analysis formula calculate:

T is the time, Variation range be 0-360 degree (9)

Obviously, by formula (6), (7), (8) and (9) as can be seen, this problem is a dynamic programming problems.In order to simplify the difficulty of optimization, improve and optimize efficient, to time t differentiate, just can obtain influencing ε to formula (8) ₃Maximum t constantly _Max, its substitution

Obtain

Need the angular displacement optimized exactly.

When carrying out the transmission shaft layout optimization, as shown in Figure 1, carry out following steps:

Step 1, as shown in Figure 2, the arrangement of selecting transmission shaft are that zigzag or W font are arranged; The initial parameter that the input shaft optimal design is required comprises: transmission shaft input end true joint angle θ ₁Initial value θ _1,0, transmission shaft output terminal true joint angle θ ₂Initial value θ _2,0, any given transmission shaft input end angular velocity omega ₁With transmission shaft input end angular acceleration ε ₁Wherein, ω ₁Span arrives maximum (top) speed, ε for the output shaft of gear-box minimum speed ₁Span be engine performance parameter 0～100rad/s ²Utilize the θ of input _1,0, θ _2,0, ω ₁And ε ₁, and the initial value ε of the transmission shaft output terminal angular acceleration that calculates _3,0

Step 2, transmission shaft layout optimization.

The present invention adopts the complex method that extensively adopts in the Optimization of Mechanical Design to be optimized.Specifically, utilize formula (4) to (9), with θ _1,0, θ _2,0And ε _3,0Be initial feasible solution, initial composite shape of structure in the feasible zone that described constraint condition is determined, the corresponding one group of (θ in each summit with k summit ₁, θ ₂) and according to (θ ₁, θ ₂) ω that calculates ₃And ε ₃Calculate the target function value on each summit, and compare, the summit of target function value maximum is defined as worst point, and obtain the new point that target function value has downtrending, and replace described worst point, constitute new complex with this new point according to selected rule; Described new complex is carried out worst point search and replace, the every change of the shape of complex once just moves to optimum point and moves a step, until ω ₃, ε ₃Approach optimum point; Two cardan axis inclination angles of transmission shaft Δ θ ' of optimum point correspondence is passed to specified file and database as optimizing the result.

Fig. 3 is the particular flow sheet of optimizing process.As shown in Figure 3, this flow process comprises the steps:

Step 1, input n, k, γ, wherein, n is the design variable number, design variable is θ in the present embodiment ₁, θ ₂And ε ₃, so n=3; K is that the summit sum of complex (gets generally that n+1≤k≤2n), γ is the condition of convergence.

Step 2, with θ _1,0, θ _2,0And ε _3,0As initial feasible solution, form k summit x of initial composite shape _j, x _j={ θ ₁, θ ₂, ε ₃, j ∈ [1,2 ... k], each summit x _jCorresponding one group of (θ ₁, θ ₂) and according to (θ ₁, θ ₂) ω that calculates ₃And ε ₃

Step 3, calculate the target function value z (x on each summit _j).

Step 4, the target function value on each summit is sorted by size, find out the most better x _L(target function value smallest point), worst point x _H(target function value maximum point) and time bad some x _G(target function value is inferior a little bigger).

Step 5, utilize the target function value z (x on each summit _j) and x _LCalculate current error of calculation δ, judge whether to satisfy δ＜γ, if then finish execution in step 15 backs; Otherwise, execution in step 6.δ can adopt formula $\mathrm{\&delta;}={\left|\frac{1}{k-1}\underset{j=1}{\overset{k}{\mathrm{\&Sigma;}}}{[z\left(x_j\right)-z\left(x_L\right)]}^2\right|}^{\frac{1}{2}}$ Calculate.

Worst point x is removed in step 6, calculating _HThe center x on (k-1) individual summit in addition _C

Step 7, according to feasibility decision rule in the complex algorithm, judge x _CWhether feasible; If then execution in step 8; Otherwise, redefine the lower limit a and the upper limit b of design variable, even: a=x _L, b=x _C, form complex again, return execution in step 2.When initial, lower limit a and upper limit b are respectively, a={ θ ₁=0 ⁰, θ ₂=0 ⁰, ε ₃=0rad/s ², b={ θ ₁=6 ⁰, θ ₂=6 ⁰, ε ₃=500rad/s ².

Step 8, exit point x negates _R, x _R=x _C+ α (x _C-x _H), wherein α is a reflection coefficient.

Step 9, judgement x _RWhether feasible, if then execution in step 10, otherwise execution in step 13.

Step 10, judge whether to satisfy z (x _R)＜z (x _H), if then execution in step 11; Otherwise, execution in step 12.

Step 11, x _RReplace x _H, return execution in step 3.

Step 12, judgement δ＜γ are if then execution in step 14; Otherwise, execution in step 13.

Step 13, dwindle step-length, promptly change reflection coefficient α, execution in step 8.

Step 14, the following bad some x _CReplace worst point x _H, return step 6.

Step 15, make constrained optimum separate being x=x _L(θ ₁, θ ₂, ε ₃), optimal value is z=z (x _L).Process ends.

So far, finished parameter optimization based on complex.

Step 3, judgement (θ _1,0-θ _2,0) whether be less than or equal to Δ θ ', if then be not optimized; Otherwise, adjust in two universal joints of transmission shaft one of them or two with Δ θ ' as the maximum transmission shaft angle of permission, thereby realize the transmission shaft layout optimization.

So far, this flow process finishes.

In sum, more than be preferred embodiment of the present invention only, be not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (1)

1. one kind little automobile chassis transmission shaft optimizing method for disposing is characterized in that, this method adopts complex method to optimize the angle of transmission shaft input end universal joint and the angle of transmission shaft output terminal universal joint; The optimization parameter of complex method is θ ₁And θ ₂, θ ₁And θ ₂Be respectively the angle of transmission shaft input end universal joint and output terminal universal joint; Objective function and constraint condition that complex method is used are respectively:

Objective function: min $z=\sqrt{|{\mathrm{\&theta;}}_1^2-{\mathrm{\&theta;}}_2^2|};$

Constraint condition: | θ ₁-θ ₂|≤6 ⁰

ε ₃≤500rad/s ²；

ω ₃、ε ₃≥0；θ ₁，θ ₂≥0；

Wherein,

ω ₃, ε ₃Be respectively the angular displacement of transmission shaft output terminal, angular velocity and angular acceleration; At known θ ₁, θ ₂, transmission shaft input end angular velocity omega ₁With transmission shaft input end angular acceleration ε ₁Situation under, can utilize the transmission shaft motion model to calculate

ω ₃, ε ₃

When carrying out the transmission shaft layout optimization, carry out following steps:

The arrangement of step 1, selection transmission shaft is that zigzag or W font are arranged; The initial parameter that the input shaft optimal design is required comprises: transmission shaft input end true joint angle θ ₁Initial value θ _1,0, transmission shaft output terminal true joint angle θ ₂Initial value θ _2,0, any given transmission shaft input end angular velocity omega ₁With transmission shaft input end angular acceleration ε ₁Utilize the θ of input _1,0, θ _2,0, ω ₁And ε ₁Calculate the initial value ε of transmission shaft output terminal angular acceleration _3,0

Step 2, with θ _1,0, θ _2,0And ε _3,0Be initial feasible solution, initial composite shape of structure in the feasible zone that described constraint condition is determined, the corresponding one group of (θ in each summit with k summit ₁, θ ₂) and according to (θ ₁, θ ₂) ω that obtains of substitution transmission shaft motion analysis model ₃And ε ₃Calculate the target function value on each summit, the target function value on each summit relatively is defined as worst point with the summit of target function value maximum, and obtains the new point that target function value has downtrending, and replaces described worst point with this new point, constitutes new complex; Described new complex is carried out worst point search and replace, until ω ₃, ε ₃Approach optimum point; Two cardan axis inclination angles of transmission shaft Δ θ ' of optimum point correspondence is exported as optimizing the result;

Step 3, judgement (θ _1,0-θ _2,0) whether be less than or equal to Δ θ ', if then be not optimized; Otherwise, adjust in two universal joints of transmission shaft one of them or two s' angle with Δ θ ' as the maximum transmission shaft angle of permission, thereby realize the transmission shaft layout optimization.

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