CN103112508B - Design method for optimum speed characteristics of trunk cab damper - Google Patents

Abstract

The invention relates to a design method for optimal speed characteristics of a truck cab shock absorber, and belongs to the technical field of cab suspension. Because the analysis and calculation of the three-mass vibration system of the cab is very complicated, there is no reliable design method for the optimal speed characteristic design of the cab shock absorber. According to the three-mass vibration system composed of wheels, vehicle body and cab and the determined optimal damping ratio of cab suspension, the present invention utilizes the safety ratio, bi-directional, lever ratio and installation angle of the shock absorber to reduce the vibration of the cab. Design the optimal speed characteristics of the actuator to obtain the segmented characteristic curves of the recovery and compression strokes required by the design. Using this design method, the reliable speed characteristics of the cab shock absorber can be obtained. The design of the shock absorber can achieve the best vibration reduction effect in the cab and meet the requirements of ride comfort. At the same time, it can avoid repeated tests, verifications and modifications. Reduced test costs for cab shock absorbers.

Description

Design Method for Optimum Speed Characteristics of Shock Absorber in Truck Cab

technical field

The invention relates to a cab shock absorber, especially a design method for optimal speed characteristics of a truck cab shock absorber.

Background technique

The damping characteristics of the cab shock absorber have an important influence on the vibration reduction effect of the cab and the comfort of the driver. However, since the full-floating cab suspension system is a three-mass vibration system composed of wheels, body mass and cab, its analysis and calculation are very complicated, and many vehicle engineering experts at home and abroad have to use a simplified single-mass vibration system model Analysis means that the vibration of the vehicle body is regarded as the excitation input of the vibration of the cab. Therefore, the damping characteristics of the cab shock absorber can only be approximated, and it is difficult to meet the design requirements of the cab shock absorber. Since the characteristics of the shock absorber are non-linear, the design characteristics of the shock absorber are usually represented by piecewise linearity. According to the information obtained, the optimal speed of the shock absorber in the truck cab has not been given at home and abroad. characteristic design method. Usually according to the type of vehicle and cab, select several similar types of vehicle cab shock absorbers based on experience, and then install them on the vehicle to pass the vehicle ride comfort test, and finally obtain the shock absorber and speed characteristics that match the vehicle cab. With the rapid development of the automobile industry, the current design method of the speed characteristics of the cab shock absorber cannot meet the design requirements of vehicle development and cab comfort.

Contents of the invention

Aiming at the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is to establish a design method for optimal speed characteristics of truck cab shock absorbers according to the optimal cab damping ratio, and its design process is shown in Figure 1.

In order to solve the above-mentioned technical problems, the design method of the optimal speed characteristic of the truck cab shock absorber provided by the present invention, the steps implemented by its technical solution are as follows:

(1) Determine the optimal damping ratio ξ _o of the cab suspension system:

According to the unilateral suspension mass m ₃ of the full-floating cab, the unilateral suspension stiffness K _s ; the sprung mass m ₂ corresponding to the front single wheel, the suspension stiffness K, and the suspension damping C; the tire mass m ₁ , the tire stiffness K _t ; road surface reference spatial frequency n ₀ ; road surface power spectral density value G _q (n ₀ ) at reference spatial frequency n ₀ , and vehicle speed v, to determine the optimal damping ratio ξ _o of the cab suspension system, namely :

ξ _o =ξ _oc +(1-0.618)(ξ _os -ξ _oc );

In the formula, ξ _oc is the objective function according to the mean square value of the vertical vibration acceleration of the cab and The obtained optimum damping ratio of cab mount based on comfort; ξ _os is the objective function based on the mean square value of wheel dynamic load and The obtained optimal damping ratio of cab mount based on safety; and They are the integral expression of the square of the amplitude-frequency characteristic of the vertical vibration acceleration of the cab and the integral expression of the square of the amplitude-frequency characteristic of the wheel dynamic load obtained by using Matlab iterative integration; and are the vertical vibration acceleration frequency response function of the cab and the wheel dynamic load frequency response function respectively, that is,

${\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 13</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, Q＝K _t (-CC _s jω ³ -C _s Kω ² -CK _s ω ² +KK _s jω); P ₀ ＝KK _s K _t ; P ₁ ＝C _s KK _t jω+CK _s K _t jω ;

P ₂ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ²

;

-m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ²

P ₃ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³

                     

-m ₃ C _s Kjω ³ -m ₂ C _s Kjω ₃ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ₃

P ₄ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ K ω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ K _s ω ⁴

                 

+m ₃ CC _s ω ⁴ +m _{2 CC s} ω ⁴ +m ₂ m 3 Kω ⁴ +m ₂ m ₃ K _t ω ⁴

P ₅ =m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₆ =-m ₁ m ₂ m ₃ ω ⁶ ;

Q ₁ ＝-m ₁ KK _s K _t jω-m ₂ KK _s K _t jω-m ₃ KK _s K _t jω;

Q ₂ ＝m ₁ C _s KK _t ω ² +m ₁ CK _s K _t ω ² +m ₃ CK _s K _t ω ² +m ₂ CK _s K _t ω ²

                 

+m ₃ C _s KK _t ω ² +m ₂ C _s KK _t ω ²

Q ₃ ＝m ₁ m ₃ K _s K _t jω ³ +m ₁ m ₃ KK _t jω ³ +m ₁ CC _s K _t jω ³ +m ₁ m ₂ K _s K _t jω ³

                 

+m ₃ CC _s K _t jω ³ +m ₂ CC _s K _t jω ³ +m ₂ m ₃ KK _t jω ³

Q ₄ ＝-m ₁ m ₂ m ₃ K _t jω ⁵ -m ₁ m ₃ C _s K _t ω ⁴ -m ₁ m ₃ CK _t ω ⁴ -m ₁ m ₂ C _s K _t ω ⁴ -m ₂ m ₃ CK _t ω ⁴ ;

P ₇ =KK _s K _t ; P ₈ =C _s KK _t jω+CK _s K _t jω;

P ₉ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ² -m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ² ;

P ₁₀ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³ -m ₃ C _s Kjω ³

                   

-m ₂ C _s Kjω ³ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ³

P ₁₁ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ K ω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ K _s ω ⁴

                     

+m ₃ CC _s ω ⁴ +m _{2 CC s} ω ⁴ +m ₂ m 3 Kω ⁴ +m ₂ m ₃ K _t ω ⁴

P ₁₂ ＝m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₁₃ ＝-m ₁ m ₂ m ₃ ω ⁶ ; C _s is the undetermined damping of the cab suspension shock absorber;

(2) Determine the initial valve opening damping coefficient C _sk1 of the recovery stroke of a single shock absorber in the cab:

According to the mass of the full-floating cab single-mounted cab is m _3d , the stiffness of the single-mounted cab K _sd , the installation lever ratio i and the installation angle θ, and the optimal damping ratio ξ _o in step (1), determine The initial valve opening damping coefficient C _sk1 of the recovery stroke of a single shock absorber in the cab is:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; sk</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sd</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; d</span>}}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; cos</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; ;</span>$

(3) Determine the initial valve opening damping force F _dk1 of the recovery stroke of a single shock absorber in the cab:

According to the initial valve opening velocity V _k1 of the cab shock absorber recovery stroke and C _sk1 in step (2), determine the initial valve opening damping force F _dk1 of the single shock absorber recovery stroke of the cab, namely:

F _dk1 = C _sk1 V _k1 ;

(4) Determine the slope k ₂ of the characteristic curve before the maximum valve opening of the single shock absorber in the cab:

According to the safety ratio η of the recovery stroke of the cab shock absorber, C _sk1 in step (2), determine the slope k ₂ of the characteristic curve before the maximum valve opening of the single shock absorber recovery stroke of the cab, namely:

k ₂ =C _sk1 /η;

(5) Determine the maximum valve opening damping force F _dk2 of the recovery stroke of a single shock absorber in the cab:

According to the initial valve opening speed V _k1 and the maximum valve opening speed V _k2 of the recovery stroke of the cab shock absorber, F _dk1 in step (3), and k ₂ in step (4), determine the single shock absorber in the cab The maximum valve opening damping force F _dk2 of the recovery stroke, namely:

F _dk2 = F _dk1 +k ₂ (V _k2 -V _k1 );

(6) Determine the initial valve opening damping force F _dk1y of the compression stroke of a single shock absorber in the cab:

According to the initial valve opening velocity V _k1y of the compression stroke of the single shock absorber in the cab and C _sk1 in step (2), determine the initial valve opening damping force F _dk1y of the compression stroke of the single shock absorber in the cab:

F _dk1y = C _sk1 V _k1y ;

(7) Determine the maximum valve opening damping force F _dk2y of the compression stroke of a single shock absorber in the cab:

According to the maximum valve opening speed V _k2y of the compression stroke of the single shock absorber in the cab and the two-way ratio β of the shock absorber, the maximum valve opening damping force F _dk2y of the compression stroke of the single shock absorber in the cab is determined, namely:

F _dk2y = β[F _dk1 +k ₂ (V _k2y -V _k1 )];

(8) Design of the optimal speed characteristic curve of a single shock absorber in the cab:

According to F _dk1 in step (3), F _dk2 in step (5), F _dk1y in step (6), and F _dk2y in step (7), the optimal speed characteristic curve of a single shock absorber in the cab Design, that is, the segmented linear characteristic curve of a single shock absorber in the cab.

The present invention has the advantage that the prior art has:

Due to the lack of calculation methods for the optimal damping ratio design of the cab, no reliable design method has been given for the speed characteristics of the cab shock absorber. Cab shock absorber, then carry out the ride comfort test of the whole vehicle, finally select the cab shock absorber, and finally design and determine the characteristics of the car cab shock absorber through the shock absorber characteristic test. The present invention is based on the driver's cab three The optimal damping ratio of the cab suspension system determined by the mass vibration system is used to design the optimal speed characteristics of the cab shock absorber by using the safety ratio, two-way, lever ratio and installation angle of the cab shock absorber, and the design results are obtained The required non-linear segmented characteristic curves of recovery and compression stroke.Using this design method can obtain reliable cab shock absorber speed characteristics, which can meet the design requirements of cab suspension system damping matching for shock absorber speed characteristics, avoiding the Repeated tests, verifications and modifications enable the cab to achieve the best damping effect and meet the requirements for ride comfort; at the same time, repeated tests, verifications and modifications can be avoided, and the test cost of the cab shock absorber can be reduced.

In order to better understand the present invention, the following will be further described in conjunction with the accompanying drawings.

Figure 1 is a design flow chart of the optimal speed characteristics of the cab shock absorber;

Fig. 2 is the best speed characteristic design curve of the cab single shock absorber of embodiment one;

Fig. 3 is the speed characteristic curve that the cab design shock absorber test of embodiment one records;

Fig. 4 is the optimal speed characteristic design curve of the cab single shock absorber of embodiment two;

Fig. 5 is the speed characteristic curve measured by the shock absorber test of the cab design of the second embodiment.

Detailed ways

The present invention will be described in further detail below by way of examples.

Example 1: One side suspension mass of a full floating cab of a truck is m ₃ =500kg, the corresponding cab suspension elastic coefficient K _s =150000N/m; the front suspension single mounting point carries the cab mass m _3d = 300kg, the cab suspension elastic coefficient K _sd corresponding to the single mounting point of the front suspension = 75000N/m; the body mass m ₂ corresponding to the single wheel = 3800kg, namely the sprung mass, the spring stiffness of the suspension K = 100000N/m, the suspension Damping C=9084N.s/m; unsprung tire mass m ₁ =200kg, tire stiffness K _t = ^900000N /m; road surface power spectral density value G _{q (} n ₀ )=256×10 ^-6 m ³ , vehicle speed ν=60km/h; shock absorber installation lever ratio i=0.95, installation angle θ=0°; shock absorber initial valve opening speed V _k1 = 0.3m/s, maximum valve opening speed V _k2 = 1m/s; compression stroke initial valve opening speed V _k1y = 0.1m/s, maximum valve opening speed V _k2y = 1m/s; shock absorber safety ratio η = 1.39, Two-way ratio β=1/3.

The design method of the optimal speed characteristic of the truck cab shock absorber provided by the example of the present invention, the design process is as shown in Figure 1, and the concrete steps are as follows:

(1) Determine the optimal damping ratio ξ _o of the cab suspension system:

According to the one-side suspension mass m ₃ of the cab = 500kg, one-side suspension stiffness K _s = 150000N/m; the sprung mass corresponding to the single wheel m ₂ = 3800kg, suspension stiffness K = 100000N/m, suspension damping C = 9084N.s/m; unsprung tire mass m ₁ = 200kg, tire stiffness K _t = 900000N/m; class C road reference space frequency n ₀ =0.1m ^-1 , reference road power spectrum at space frequency n ₀ Density value G _q (n ₀ )=256×10 ^-6 m ³ ; vehicle speed ν=60km/h, determine the optimal damping ratio ξ _o of the cab suspension system, namely:

ξ _o =ξ _oc +(1-0.618)(ξ _os -ξ _oc )=0.2701;

In the formula, ξ _oc =0.1816, according to and The obtained optimum damping ratio of cab mount based on comfort; ξ _os =0.4134, is based on and The obtained optimal damping ratio of cab mount based on safety; among them, and The integral expression of the square of the amplitude-frequency characteristic of the vertical vibration acceleration of the cab and the integral expression of the square of the amplitude-frequency characteristic of the dynamic load of the wheel are respectively obtained by using Matlab iterative integration; and are the vertical vibration acceleration frequency response function of the cab and the wheel dynamic load frequency response function respectively, that is,

${\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\stackrel{<span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; ;</span>$

${\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 9</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 13</span>}}}<span\; class="notranslate">\; ;</span>$

Among them, Q＝K _t (-CC _s jω ³ -C _s Kω ² -CK _s ω ² +KK _s jω); P ₀ ＝KK _s K _t ; P ₁ ＝C _s KK _t jω+CK _s K _t jω ;

P ₂ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ²

                 

-m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ²

P ₃ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³

                              ;

-m ₃ C _s Kjω ³ -m ₂ C _s Kjω ₃ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ₃

P ₄ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ K ω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ K _s ω ⁴

                   

+m ₃ CC _s ω ⁴ +m _{2 CC s} ω ⁴ +m ₂ m 3 Kω ⁴ +m ₂ m ₃ K _t ω ⁴

P ₅ =m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₆ =-m ₁ m ₂ m ₃ ω ⁶ ;

Q ₁ ＝-m ₁ KK _s K _t jω-m ₂ KK _s K _t jω-m ₃ KK _s K _t jω;

Q ₂ ＝m ₁ C _s KK _t ω ² +m ₁ CK _s K _t ω ² +m ₃ CK _s K _t ω ² +m ₂ CK _s K _t ω ²

                   

+m ₃ C _s KK _t ω ² +m ₂ C _s KK _t ω ²

Q ₃ ＝m ₁ m ₃ K _s K _t jω ³ +m ₁ m ₃ KK _t jω ³ +m ₁ CC _s K _t jω ³ +m ₁ m ₂ K _s K _t jω ³

+m ₃ CC _s K _t jω ³ +m ₂ CC _s K _t jω ³ +m ₂ m ₃ KK _t jω ³

                   ;

Q ₄ ＝-m ₁ m ₂ m ₃ K _t jω ⁵ -m ₁ m ₃ C _s K _t ω ⁴ -m ₁ m ₃ CK _t ω ⁴ -m ₁ m ₂ C _s K _t ω ⁴ -m ₂ m ₃ CK _t ω ⁴ ;

P ₇ =KK _s K _t ; P ₈ =C _s KK _t jω+CK _s K _t jω;

P ₉ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ² -m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ² ;

P ₁₀ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³ -m ₃ C _s Kjω ³

               

-m ₂ C _s Kjω ³ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ³

P ₁₁ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ K ω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ Ks ω ⁴

                 

+m ₃ CC _s ω ⁴ +m _{2 CC s} ω ⁴ +m ₂ m 3 Kω ⁴ +m ₂ m ₃ K _t ω ⁴

P ₁₂ ＝m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₁₃ ＝-m ₁ m ₂ m ₃ ω ⁶ ; C _s is the undetermined damping of the cab suspension shock absorber;

(2) Determine the initial valve opening damping coefficient C _sk1 of the recovery stroke of the cab shock absorber:

According to the single suspension point of the cab, that is, the mass at the single shock absorber is m _3d =300kg, the stiffness K _sd =75000N/m, the installation lever ratio i=0.95 and the installation angle θ=0°, and step (1) ξ _o = 0.2701, the initial valve opening damping coefficient C _sk1 to determine the recovery stroke of the cab shock absorber is:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; sk</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sd</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; d</span>}}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; cos</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2839.22</span>}\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ;</span>$

(3) Determine the initial valve opening damping force F _dk1 of the recovery stroke of the cab shock absorber:

According to the initial valve opening velocity V _k1 = 0.3m/s of the shock absorber recovery stroke, and C _sk1 = 2839.22Ns/m in step (2), determine the initial valve opening damping force F _dk1 of the cab shock absorber recovery stroke ,Right now:

F _dk1 = C _sk1 V _k1 = 851.77N;

(4) Determine the slope k ₂ of the characteristic curve before the maximum valve opening of the cab shock absorber recovery stroke:

According to the safety ratio η=1.39 of the recovery stroke of the cab shock absorber, and C _sk1 =2839.22Ns/m in step (2), determine the slope k ₂ of the characteristic curve before the maximum valve opening of the cab shock absorber recovery stroke, namely:

k ₂ =C _sk1 /η=2042.60;

(5) Determine the maximum valve opening damping force F _dk2 of the recovery stroke of the cab shock absorber:

According to the initial valve opening speed V _k1 =0.3m/s and the maximum valve opening speed V _k2 =1.0m/s of the cab shock absorber, F _dk1 in step (3) =851.77N, and in step (4) k ₂ =2042.602, to determine the maximum valve opening damping force F _dk2 of the recovery stroke of the cab shock absorber, namely:

F _dk2 = F _dk1 + k ₂ (V _k2 -V _k1 ) = 2281.59N;

(6) Determine the initial valve opening damping force F _dk1y of the compression stroke of the cab shock absorber:

According to the initial valve opening velocity V _k1y of the cab shock absorber compression stroke = 0.1m/s, C _sk1 = 2839.22Ns/m in step (2), determine the initial valve opening damping force F of the cab shock absorber compression stroke _dk1y :

F _dk1y = C _sk1 V _k1y = 283.92N;

(7) Determine the maximum valve opening damping force F _dk2y of the compression stroke of the cab shock absorber:

According to the maximum valve opening speed V _k2y of the cab shock absorber compression stroke = 1.0m/s, the two-way ratio of the shock absorber β = 1/3, determine the maximum valve opening damping force F _dk2y of the cab shock absorber compression stroke, namely :

F _dk2y = β[F _dk1 + k ₂ (V _k2y -V _k1 )] = 760.53N;

(8) Design of the optimal speed characteristic curve of the cab shock absorber:

According to _Fdk1 =851.77N in step (3), Fdk2=2281.59N in step (5), _Fdk1y =283.92N in step (6), and _Fdk2y = _760.53N in step (7), for The optimal speed characteristic curve of the cab shock absorber is designed, and the segmented linear characteristic curve of the cab shock absorber is obtained, as shown in Figure 2.

Using the fully automatic hydraulic servo vehicle suspension comprehensive performance test bench, the designed shock absorber is tested for characteristics. The characteristic curve of the shock absorber obtained from the test is shown in Figure 3, which is consistent with the design requirements in Figure 2. The results show that the shock absorber The design method of optimal speed characteristic of truck cab shock absorber is correct.

Example 2: The rear suspension single point of a truck’s fully floating cab means the mass of the cab carried by a single shock absorber m _3d = 200kg, and the rear suspension single point corresponds to the cab suspension elastic coefficient K _sd = 75000N/m ; Other vehicle parameters and shock absorber parameters are the same as in Example 1.

Adopt the design steps of embodiment one, namely:

(1) Determine the optimal damping ratio ξ _o of the cab suspension system:

According to the one-side suspension mass of the cab m ₃ =500kg, one-side suspension stiffness K _s =150000N/m, the sprung mass corresponding to the single wheel _m2 =3800kg, suspension stiffness K=100000N/m, suspension damping C＝9084N.s/m, unsprung tire mass m ₁ ＝200kg, tire stiffness K _t ＝900000N/m; Class C road reference space frequency n ₀ ＝0.1m ^-1 ; reference road power spectrum at space frequency n ₀ Density value G _q (n ₀ )=256×10 ^-6 m ³ , and vehicle speed ν=60km/h, determine the optimal damping ratio ξ _o of the cab suspension system, namely:

ξ _o =ξ _oc +(1-0.618)(ξ _os -ξ _oc )=0.2701;

In the formula, ξ _oc = 0.1816, which is based on and The obtained optimum damping ratio of cab mount based on comfort; ξ _os =0.4134, is based on and The obtained optimal damping ratio of cab mount based on safety;

(2) Determine the initial valve opening damping coefficient C _sk1 of the recovery stroke of the cab shock absorber:

According to the mass of the rear suspension single suspension point (single shock absorber) of the cab is m _3d = 200kg, the corresponding stiffness of the rear suspension single suspension point K _sd = 75000N/m, the installation lever ratio i = 0.95 and the installation angle θ = 0°, and ξ _o = 0.2701 in step (1), determine the initial valve opening damping coefficient C _sk1 of the recovery stroke of the cab shock absorber as:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; sk</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sd</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; d</span>}}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; cos</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 2318.22</span>}\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; .</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; ;</span>$

(3) Determine the initial valve opening damping force F _dk1 of the recovery stroke of the cab shock absorber:

According to the initial valve opening speed of the shock absorber V _k1 =0.3m/s, and C _sk1 =2318.21Ns/m in step (2), determine the initial valve opening damping force F _dk1 of the recovery stroke of the cab shock absorber, namely:

F _dk1 = C _sk1 V _k1 = 695.46N;

(4) Determine the slope k ₂ of the characteristic curve before the maximum valve opening of the cab shock absorber recovery stroke:

According to the safety ratio η=1.39 of the recovery stroke of the cab shock absorber, C _sk1 =2318.21Ns/m in step (2), determine the slope k ₂ of the characteristic curve before the maximum valve opening of the cab shock absorber recovery stroke, namely:

k ₂ =C _sk1 /η=1667.78;

(5) Determine the maximum valve opening damping force F _dk2 of the recovery stroke of the cab shock absorber:

According to the initial valve opening speed V _k1 = 0.3m/s and the maximum valve opening speed V _k2 = 1.0m/s of the cab shock absorber, F _dk1 in step (3) = 695.46N, and in step (4) k ₂ =1667.78, to determine the maximum valve opening damping force F _dk2 of the recovery stroke of the cab shock absorber, namely:

F _dk2 = F _dk1 + k ₂ (V _k2 -V _k1 ) = 1862.91N;

(6) Determine the initial valve opening damping force F _dk1y of the compression stroke of the cab shock absorber:

According to the initial valve opening speed V _k1y of the compression stroke of the cab shock absorber = 0.1m/s, C _k1 = 2967.46Ns/m in step (2), determine the initial valve opening damping force F of the cab shock absorber compression stroke _dk1y :

F _dk1y = C _sk1 V _k1y = 231.82N;

(7) Determine the maximum valve opening damping force F _dk2y of the compression stroke of the cab shock absorber:

According to the maximum valve opening speed V _k2y of the cab shock absorber compression stroke = 1.0m/s, the two-way ratio of the shock absorber β = 1/3, determine the maximum valve opening damping force F _dk2y of the cab shock absorber compression stroke, namely :

F _dk2y = β[F _dk1 + k ₂ (V _k2y -V _k1 )] = 620.97N;

(8) Design of the optimal speed characteristic curve of the cab shock absorber:

According to _Fdk1 =695.46N in step (3), Fdk2=1862.91N in step (5), _Fdk1y = _231.82N in step (6), and _Fdk2y =620.97N in step (7), for The optimal speed characteristic curve of the cab shock absorber is designed, and the segmented linear characteristic curve of the cab shock absorber is obtained, as shown in Figure 4.

Using the full-automatic hydraulic servo vehicle suspension comprehensive performance test bench, the designed shock absorber is tested. The characteristic curve of the shock absorber obtained from the test is shown in Figure 5, which is consistent with the design requirements in Figure 4. The results show that the shock absorber The optimal speed characteristic design method of truck cab shock absorber is correct.

Claims (1)

1. The design method of the optimal speed characteristics of the truck cab shock absorber, the specific steps are as follows: (1) Determine the optimal damping ratio ξ _o of the cab suspension system: According to the unilateral suspension mass m ₃ of the full-floating cab, the unilateral suspension stiffness K _s ; the sprung mass m ₂ corresponding to the front single wheel, the suspension stiffness K, and the suspension damping C; the tire mass m ₁ , the tire stiffness K _t ; road surface reference spatial frequency n ₀ ; road surface power spectral density value G _q (n ₀ ) at reference spatial frequency n ₀ , and vehicle speed v, to determine the optimal damping ratio ξ _o of the cab suspension system, namely : ξ _o =ξ _oc +(1-0.618)(ξ _os -ξ _oc ); In the formula, ξ _oc is the objective function according to the mean square value of the vertical vibration acceleration of the cab and The obtained optimum damping ratio of cab mount based on comfort; ξ _os is the objective function based on the mean square value of wheel dynamic load The obtained optimal damping ratio of cab mount based on safety; They are the integral expression of the square of the amplitude-frequency characteristic of the vertical vibration acceleration of the cab and the integral expression of the square of the amplitude-frequency characteristic of the wheel dynamic load obtained by using Matlab iterative integration; and are the vertical vibration acceleration frequency response function of the cab and the wheel dynamic load frequency response function respectively, that is, $\mathrm{<span\; class="notranslate">\; h</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; z</span>}}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&Center\; Dot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; Q</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 5</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 6</span>}}}<span\; class="notranslate">\; ;</span>$ $\mathrm{<span\; class="notranslate">\; h</span>}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j\&omega;</span>}<span\; class="notranslate">\; )</span>}_{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; ~</span>\stackrel{<span\; class="notranslate">\; \&CenterDot;</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 7</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 8</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 10</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 13</span>}}}<span\; class="notranslate">\; ;</span>$ Among them, Q＝K _t (-CC _s jω ³ -C _s Kω ² -CK _s ω ² +KK _s jω); P ₀ ＝KK _s K _t ; P ₁ ＝C _s KK _t jω+CK _s K _t jω ; P ₂ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ² -m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ² ; P ₃ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³ -m ₃ C _s Kjω ³ -m ₂ C _s Kjω ₃ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ₃ ; P ₄ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ Kω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ K _s ω ⁴ +m ₃ CC _s ω ⁴ +m ₂ CC _s ω ⁴ +m ₂ m ₃ Kω ⁴ +m ₂ m ₃ K _t ω ⁴ ; P ₅ =m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₆ =-m ₁ m ₂ m ₃ ω ⁶ ; Q ₁ ＝-m ₁ KK _s K _t jω-m ₂ KK _s K _t jω-m ₃ KK _s K _t jω; Q ₂ ＝m ₁ C _s KK _t ω ² +m ₁ CK _s K _t ω ² +m ₃ CK _s K _t ω ² +m ₂ CK _s K _t ω ² +m ₃ C _s KK _t ω ² +m ₂ C _s KK _t ω ² ; Q ₃ ＝m ₁ m ₃ K _s K _t jω ³ +m ₁ m ₃ KK _t jω ³ +m ₁ CC _s K _t jω ³ +m ₁ m ₂ K _s K _t jω ³ +m ₃ CC _s K _t jω ³ +m ₂ CC _s K _t jω ³ +m ₂ m ₃ KK _t jω ³ ; Q ₄ ＝-m ₁ m ₂ m ₃ K _t jω ⁵ -m ₁ m ₃ C _s K _t ω ⁴ -m ₁ m ₃ CK _t ω ⁴ -m ₁ m ₂ C _s K _t ω ⁴ -m ₂ m ₃ CK _t ω ⁴ ; P ₇ =KK _s K _t ; P ₈ =C _s KK _t jω+CK _s K _t jω; P ₉ ＝-m ₁ KK _s ω ² -m ₃ KK _s ω ² -m ₂ KK _s ω ² -m ₃ K _s K _t ω ² -m ₃ KK _t ω ² -CC _s K _t ω ² -m ₂ K _s K _t ω ² ; P ₁₀ ＝-m ₁ C _s Kjω ³ -m ₁ CK _s jω ³ -m ₃ CK _s jω ³ -m ₂ CK _s jω ³ -m ₃ C _s Kjω ³ -m ₂ C _s Kjω ³ -m ₃ C _s K _t jω ³ -m ₃ CK _t jω ³ -m ₂ C _s K _t jω ³ ; P ₁₁ ＝m ₁ m ₃ K _s ω ⁴ +m ₁ m ₃ Kω ⁴ +m ₁ CC _s ω ⁴ +m ₁ m ₂ K _s ω ⁴ +m ₃ CC _s ω ⁴ +m ₂ CC _s ω ⁴ +m ₂ m ₃ Kω ⁴ +m ₂ m ₃ K _t ω ⁴ ; P ₁₂ ＝m ₁ m ₃ C _s jω ⁵ +m ₁ m ₃ Cjω ⁵ +m ₁ m ₂ C _s jω ⁵ +m ₂ m ₃ Cjω ⁵ ; P ₁₃ ＝-m ₁ m ₂ m ₃ ω ⁶ ; C _s is the undetermined damping of the cab suspension shock absorber; (2) Determine the initial valve opening damping coefficient C _sk1 of the recovery stroke of a single shock absorber in the cab: According to the mass of the full-floating cab single-mounted cab is m _3d , the stiffness of the single-mounted cab K _sd , the installation lever ratio i and the installation angle θ, and the optimal damping ratio ξ _o in step (1), determine The initial valve opening damping coefficient C _sk1 of the recovery stroke of a single shock absorber in the cab is: ${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; sk</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&xi;</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; sd</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; d</span>}}}}{{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; cos</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; ;</span>$ (3) Determine the initial valve opening damping force F _dk1 of the recovery stroke of a single shock absorber in the cab: According to the initial valve opening velocity V _k1 of the cab shock absorber recovery stroke and C _sk1 in step (2), determine the initial valve opening damping force F _dk1 of the single shock absorber recovery stroke of the cab, namely: F _dk1 = C _sk1 V _k1 ; (4) Determine the slope k ₂ of the characteristic curve before the maximum valve opening of the single shock absorber in the cab: According to the safety ratio η of the recovery stroke of the cab shock absorber, C _sk1 in step (2), determine the slope k ₂ of the characteristic curve before the maximum valve opening of the single shock absorber recovery stroke of the cab, namely: k ₂ =C _sk1 /η; (5) Determine the maximum valve opening damping force F _dk2 of the recovery stroke of a single shock absorber in the cab: According to the initial valve opening speed V _k1 and the maximum valve opening speed V _k2 of the recovery stroke of the cab shock absorber, F _dk1 in step (3), and k ₂ in step (4), determine the single shock absorber in the cab The maximum valve opening damping force F _dk2 of the recovery stroke, namely: F _dk2 = F _dk1 +k ₂ (V _k2 -V _k1 ); (6) Determine the initial valve opening damping force F _dk1y of the compression stroke of a single shock absorber in the cab: According to the initial valve opening velocity V _k1y of the compression stroke of the single shock absorber in the cab and C _sk1 in step (2), determine the initial valve opening damping force F _dk1y of the compression stroke of the single shock absorber in the cab: F _dk1y = C _sk1 V _k1y ; (7) Determine the maximum valve opening damping force F _dk2y of the compression stroke of a single shock absorber in the cab: According to the maximum valve opening speed V _k2y of the compression stroke of the single shock absorber in the cab and the two-way ratio β of the shock absorber, the maximum valve opening damping force F _dk2y of the compression stroke of the single shock absorber in the cab is determined, namely: F _dk2y = β[F _dk1 +k ₂ (V _k2y -V _k1 )]; (8) Design of the optimal speed characteristic curve of a single shock absorber in the cab: According to F _dk1 in step (3), F _dk2 in step (5), F _dk1y in step (6), and F _dk2y in step (7), the optimal speed characteristic curve of a single shock absorber in the cab Design, that is, the segmented linear characteristic curve of a single shock absorber in the cab.