阅读说明：本技术 一种主动悬架式星球车移动系统构型优化设计方法 (Configuration optimization design method for active suspension type planet vehicle moving system ) 是由 潘冬 袁宝峰 刘雅芳 王瑞 邹猛 贾阳 陈百超 党兆龙 陈明 于 2021-08-31 设计创作，主要内容包括：本发明涉及一种主动悬架式星球车移动系统构型优化设计方法,根据主动悬架式移动系统具体结构及其总体功能,具体阐述主动可变悬架式移动系统构型优化设计的方法,设计设定主摇臂前段长度、主摇臂后段长度、副摇臂长度以及其与其他部件的夹角大小,并分析主摇臂、副摇臂各尺寸之间的函数关系：建立几何模形,通过优化设计参数,在火星车悬架调整过程中,使得主摇臂间夹角和主摇臂后半段与水平线间夹角的非线性关系近似线性化,实现差动机构在调节车厢高度时保持车厢水平。(The invention relates to an optimal design method for the configuration of an active suspension type planet vehicle moving system, which particularly explains the optimal design method for the configuration of an active variable suspension type moving system according to the specific structure and the overall function of the active suspension type moving system, designs and sets the length of the front section of a main rocker arm, the length of the rear section of the main rocker arm, the length of an auxiliary rocker arm and the size of an included angle between the auxiliary rocker arm and other components, and analyzes the functional relationship among the sizes of the main rocker arm and the auxiliary rocker arm: and establishing a geometric model, and enabling the nonlinear relation between the included angle between the main rocker arms and the included angle between the rear half section of the main rocker arm and the horizontal line to be approximately linearized in the adjustment process of the Mars vehicle suspension by optimizing design parameters, so that the differential mechanism can keep the carriage horizontal when the height of the carriage is adjusted.)

1. The active suspension type planet vehicle moving system configuration optimization design method is characterized in that a main rocker arm and an auxiliary rocker arm (7) of a suspension are connected with a carriage (9), the planet vehicle moving system comprises two sets of moving system units which are installed on the suspension and symmetrically arranged on two sides of the carriage (9), each moving system unit comprises one set of included angle adjusting mechanism (3), three sets of wheel driving mechanisms (1), three sets of wheel steering mechanisms (2) and one set of clutch mechanism (4), each main rocker arm comprises a main rocker arm front section (5) and a main rocker arm rear section (6), each included angle adjusting mechanism (3) is a single-input double-output differential mechanism, two output ends of each differential mechanism are respectively connected with the main rocker arm front section (5) and the main rocker arm rear section (6) in a corresponding transmission mode, and the main rocker arm front section (5) passes through the wheel steering mechanisms (2) and the wheel driving mechanisms (8) corresponding to wheels (3), (2) 1) The two ends of the auxiliary rocker arm (7) are in transmission connection with the wheel driving mechanism (1) corresponding to the wheels (8) through the corresponding wheel steering mechanism (2) respectively; the rear section (6) of the main rocker arm is hinged with the middle part of the auxiliary rocker arm (7) through the clutch mechanism (4);

the angle variation amount omega 1 of the front section (5) of the main rocker arm relative to the differential mechanism₁The angle variation amount omega 1 of the rear section (6) of the main rocker arm relative to the output shaft of the differential mechanism₂The difference between the two is the variation delta alpha of the opening angle of the main rocker arm: Δ α ═ ω 1₂-ω1₁The compound of the formula (1),

omega 1 when the opening angles of the main rocker arms on two sides of the carriage (9) are synchronously changed₁Namely the angular variation delta theta of the front section (5) of the main rocker arm relative to the vehicle body: Δ θ ═ ω 1₁Formula (2)

By omega 1₂-ω1₁And ω 1₁The ratio of (a) to (b):

the opening angle of the main rocker arm and the pitching attitude of the carriage (9) are corrected by adopting the above formula, the rod lengths of the front section (5) and the rear section (6) of the main rocker arm are designed to enable delta theta and delta alpha to be linearly related, and the linear correlation coefficient is just k, so that the differential mechanism can keep the carriage (9) horizontal when the height of the carriage (9) is adjusted.

2. The optimal design method for the configuration of the active suspension type planet vehicle moving system according to claim 1, wherein the differential mechanism is a planetary gear train, a sun gear in the planetary gear train is fixedly connected with the front section (5) of the main rocker arm, a gear ring is fixedly connected with the rear section (6) of the main rocker arm, and a planet carrier is fixedly connected with a differential shaft.

3. The method of claim 1, wherein the linearly correlating Δ θ with Δ α comprises:

(1) setting the length l of the front section (5) of the main rocker arm₁The length l of the rear section (6) of the main rocker arm₂(ii) a The length l of the auxiliary rocker arm (7)₃(ii) a The included angle alpha between the main rocker arms, and the included angle theta between the rear half section (6) of the main rocker arms and the horizontal line; an included angle beta is formed between the front half section and the rear half section of the auxiliary rocker arm (7); the system centroid is offset from the center line by a distance e; wheel spacing l between front wheel and middle wheel₄The wheel interval l between the middle wheel and the rear wheel₅；

(2) By analyzing the functional relationship between the dimensions of the main rocker arm and the auxiliary rocker arm (7): establishing a geometric model, wherein the geometric relations shown in the formulas (4) to (8) are always satisfied among the main rocker arm, the auxiliary rocker arm (7) and the carriage (9) in the adjustment process when the angle is 0< alpha < pi:

in the simultaneous expression, theta can be expressed as a function of alpha, the nonlinear relation between alpha and theta is approximately linearized by optimizing design parameters, and the condition that the planetary gear train horizontally lifts the carriage (9) is met

4. The method for optimizing the configuration of an active suspension type planet vehicle moving system according to claim 3, wherein the main rocker arm, the auxiliary rocker arm (7) and the differential mechanism are designed to meet the following conditions:

the distance between the front wheel and the middle wheel in the planet vehicle moving system is equal to the distance between the middle wheel and the rear wheel, and l₄＝l₅；

The differential shaft of the differential mechanism is close to a plane which passes through the axis of the middle wheel and is vertical to the ground, and e is in proportion to 0;

the differential shaft of the differential mechanism is close to the bottom surface of the carriage (9), and d ^ 0;

the ground clearance of the bottom surface of the carriage (9) is greater than the diameter of the wheel (8), and H is greater than D;

the articulated shaft of the rear section (6) of the main rocker arm and the clutch mechanism (4) is positioned on a middle dividing line of the connecting line of the middle wheel and the rear wheel, i₃＝l₆；

The hinge shaft ground clearance is not more than the differential shaft ground clearance, H₁H + d is less than or equal to H + d, and the articulated shaft is separated fromThe height of the ground is greater than the diameter H of the wheel (8)₁＞D；

The diameter of the wheel (8) is larger than zero, and D is larger than 0.

5. The configuration optimization design method of the active suspension type planet vehicle moving system according to claim 3, characterized in that only the horizontal lifting of the carriage (9) is taken as an optimization target, the absolute value of the correlation coefficient of the main rocker arm and the auxiliary rocker arm satisfying the objective function p as alpha and theta approaches to 1,

ρ is 1- | r | formula (10)

Technical Field

The invention relates to the technical field of mobile robots, in particular to a configuration optimization design method for an active suspension type planet vehicle mobile system.

Background

The surface of an extraterrestrial celestial body may have bad weather such as sand dust, storm and the like, so that the conversion speed of the surface terrain is higher, more seriously, a layer of hard sand shell is arranged on the surface of part of sandy land, the inside of the sandy land is soft sand, and the deep subsidence without signs of wheels is very easily caused in the process of the inspection and the detection of a celestial body vehicle, for example, American chance vehicles and courage vehicles cannot be separated due to the occurrence of subsidence, so that the task fails, and the difficulty of the escape after the subsidence always troubles the technical difficulty of the celestial body vehicle.

The traditional planet vehicles all adopt passive suspension type mobile systems, and do not have the capabilities of configuration adjustment and creeping escape, and the Chinese congratulation mars vehicle adopts a brand-new active suspension type mobile system, so that the expansion functions of vehicle body height adjustment, creeping walking and the like can be realized through the active deformation of a suspension, and the capabilities of sinking escape and obstacle passing of the mars vehicle are effectively improved.

The specific components and the overall functions of the active suspension type moving system are described in more detail in the active suspension type train moving mechanism disclosed in the related patent No. CN105235468A and the variable active suspension mechanism of a planet train disclosed in the patent No. CN201911135824.9, but the design method and the design parameters of the suspension system configuration are not described, and the related contents are not found in the technical literature in the related field, so that the related technical staff are in a state that they know the situation and do not know the situation.

Therefore, how to provide a configuration optimization method for an active suspension type planet vehicle moving system is a technical problem which needs to be solved urgently by the technical personnel in the field.

Disclosure of Invention

The invention provides a nonlinear and strong-coupling active suspension type celestial body moving system overall configuration parameter optimization design method, which solves the technical problems that the existing celestial body moving system is high in parallel lifting, wheel lifting, crawling walking, configuration parameters and mechanism reduction ratio.

The technical scheme for solving the technical problems is as follows: a design method for optimizing the configuration of an active suspension type planet vehicle moving system comprises the steps that a main rocker arm and an auxiliary rocker arm of a suspension are connected with a carriage, the planet vehicle moving system comprises two sets of moving system units which are arranged on the suspension and are symmetrically arranged on two sides of the carriage, each moving system unit comprises a set of included angle adjusting mechanism, three sets of wheel driving mechanisms, three sets of wheel steering mechanisms and a set of clutch mechanism, the main rocker arm comprises a front section of the main rocker arm and a rear section of the main rocker arm, each included angle adjusting mechanism is a single-input and double-output differential mechanism, two output ends of each differential mechanism are respectively in transmission connection with the front section of the main rocker arm and the rear section of the main rocker arm, the front section of the main rocker arm is in transmission connection with a wheel driving mechanism of a corresponding wheel through the wheel steering mechanism, and two ends of the auxiliary rocker arm are respectively in transmission connection with the wheel driving mechanism of the corresponding wheel through the corresponding wheel steering mechanism; the rear section of the main rocker arm is hinged with the middle part of the auxiliary rocker arm through a clutch mechanism;

the included angle between the front section of the main rocker arm and the rear section of the main rocker arm is the opening angle of the main rocker arm, and the angle variation omega 1 of the front section of the main rocker arm relative to the differential mechanism₁Angle variation amount ω 1 of the rear end of the main rocker arm with respect to the output shaft of the differential mechanism₂The difference between the two is the variation delta alpha of the opening angle of the main rocker arm: Δ α ═ ω 1₂-ω1₁The compound of the formula (1),

omega 1 when the opening angles of the main rocker arms on two sides of the carriage synchronously change₁Namely the angle variation delta theta of the front section of the main rocker arm relative to the vehicle body: Δ θ ═ ω 1₁The compound of the formula (2),

by omega 1₂-ω1₁And ω 1₁The ratio of (a) to (b):the compound of the formula (3),

the opening angle of the main rocker arm and the pitching attitude of the carriage are corrected by adopting the above formula, the rod lengths of the front section of the main rocker arm and the rear section of the main rocker arm are designed to ensure that delta theta is linearly related to delta alpha, and the linear correlation coefficient is just k, so that the differential mechanism can keep the carriage horizontal when the height of the carriage is adjusted.

The invention has the beneficial effects that: the suspension configuration optimization method can support the realization of the configuration of an active suspension type planet vehicle moving system, and the linear correlation coefficient is just k by designing the rod lengths of the front section of the main rocker arm and the rear section of the main rocker arm so that the delta theta and the delta alpha are linearly correlated, so that the functions of horizontal lifting, creeping stepping, wheel lifting and the like of a planet vehicle carriage can be realized, the passing performance and the detrapping capacity of the planet vehicle moving system are improved, and the service life of the planet vehicle is prolonged.

Furthermore, the differential mechanism can be a planetary gear train, a sun gear in the planetary gear train is fixedly connected with the front section of the main rocker arm, a gear ring is fixedly connected with the rear section of the main rocker arm, and a planet carrier is fixedly connected with the differential shaft.

Further, linearly correlating Δ θ with Δ α includes:

(1) setting the length l of the front section of the main rocker arm₁Length l of rear section of main rocker arm₂(ii) a Length l of auxiliary rocker arm₃(ii) a The included angle alpha between the main rocker arms and the included angle theta between the rear half section of the main rocker arm and the horizontal line; an included angle beta is formed between the front half section and the rear half section of the auxiliary rocker arm; the system centroid is offset from the center line by a distance e; wheel spacing l between front wheel and middle wheel₄The wheel spacing l between the middle wheel and the rear wheel₅；

(2) Analyzing the functional relation between the sizes of the main rocker arm and the auxiliary rocker arm: establishing a geometric model, wherein in the adjustment process, the main rocker arm, the auxiliary rocker arm and the carriage always satisfy the geometric relations shown in the formulas (4) to (9) when the alpha is more than 0 and less than pi:

in the simultaneous expression, theta can be expressed as a function of alpha, the nonlinear relation between alpha and theta is approximately linearized by optimizing design parameters, and the condition that the planetary gear train horizontally lifts the carriage is met

The adoption of the further beneficial effects is as follows: in the process of adjusting the suspension of the planet vehicle, the main rocker arm, the auxiliary rocker arm and the carriage always satisfy the geometric parameters of a formula (4) -a formula (8), the nonlinear relation between alpha and theta is approximately linearized by optimizing the lengths of all parts and the included angles among the parts, and the horizontal lifting carriage of the planet vehicle can be supported.

Further, the parameter optimization constraints are as follows:

(1) the load of the differential is minimum, the vertical line of the vehicle body center on the flat ground should be as close to the axis of the vehicle body differential as possible, the load of the differential should be as small as possible, certain vertical force is applied to the front end/rear end of the carriage during design, and the rigidity of the differential should ensure that the vehicle body does not generate large pitching.

(2) The inside of the vehicle body is provided with constraint, because a differential and a pivot component penetrate through the whole vehicle body, and an included angle adjusting mechanism is introduced into the active suspension, the design ensures that a middle connecting shaft system of the moving mechanism is close to the lower surface of the vehicle body, and a space is reserved for the pivot swinging under the rugged terrain and the included angle adjusting mechanism component. Therefore, the differential is arranged on the lower bottom plate of the vehicle body, and the difference between the height of the axis from the bottom plate and the outer contour of the middle shafting is not too large.

(3) The normal loads of the wheels are uniformly distributed and restrained, the normal loads of the wheels are uniformly distributed as far as possible when the moving mechanism is arranged on the flat ground, and the moving axis is closer in consideration of the difference of the center of mass distance of the vehicle body. The differential axle should therefore be arranged as far as possible above the middle wheel, the front middle wheel and the middle rear wheel being equally spaced in the nominal suspension.

(4) The attitude stability of the vehicle body is restricted, and when the moving mechanism runs in a rough terrain in a nominal state, the terrain smoothness of the main and auxiliary rocker arm type suspension frames is exerted. Therefore, the height of the hinge point of the main rocker arm and the auxiliary rocker arm is not greater than the height of the differential shaft; considering the trafficability requirement, the height of the hinge point of the main rocker and the auxiliary rocker is not lower than the diameter of the wheel from the ground.

(5) The slope static stability is restrained, and the main rocker arm suspension and the auxiliary rocker arm suspension are required to ensure sufficient slope stability. Sufficient stability is provided in view of body lifting and creeping travel on the hill. The distance between the front wheels and the rear wheels and the distance between the left wheels and the right wheels are set according to the requirements, so that the mass center of the carriage is always positioned in a closed area defined by the wheel-ground contact points.

(6) The mass center adjustment range is constrained to the maximum, and the normal load of the wheel may need to be adjusted when the vehicle runs on a slope or is out of trouble, so that the passing performance of the moving mechanism is improved. The implementation capacity of the front wheel and the rear wheel for lifting is closely related to the adjustment of the mass center of the vehicle body. Therefore, when suspension parameters are set, the mass center can be ensured to have a larger adjusting range in front of and behind the middle wheel under the condition that the vehicle body is not unstable. This constraint is also an important basis for estimation of the hill climbing and obstacle crossing stability regions.

(7) The creep advancing step is constrained to the maximum, the lifting height of the vehicle body is limited by considering the stability of the vehicle body, the distance between front wheels and rear wheels of the moving mechanism is limited by the size of the launching cabin, enough distance is reserved between the front wheels and the middle wheels when the terrain is rugged, and the creep advancing step and efficiency are directly influenced by the configuration of the length of the suspension rod. Therefore, the creep step should be increased as much as possible while satisfying the stability of the vehicle body.

(8) The driving moment of the main rocker included angle adjusting mechanism is minimum constrained, and the driving moment of the main rocker included angle adjusting mechanism is required to be as small as possible under the working conditions of nominal suspension (walking, climbing and obstacle crossing), suspension folding and unfolding, wheel lifting, creeping and advancing and the like, so that the driving power of the included angle adjusting mechanism and the volume and mass of the speed reducing mechanism are reduced.

(9) The driving torque of the main rocker arm clutch mechanism and the auxiliary rocker arm clutch mechanism is minimum constrained, the clutch works when the wheels are lifted and walk, the reasonable planning of suspension parameters is beneficial to reducing the driving torque of the clutch mechanism under relevant working conditions, and the driving power, the quality and the volume of the clutch mechanism are effectively reduced.

Further, the main rocker arm, the auxiliary rocker arm and the differential mechanism are designed to satisfy the following conditions:

the distance between the front wheel and the middle wheel in the planet vehicle moving system is equal to the distance between the middle wheel and the rear wheel₄＝l₅；

A differential shaft of the differential mechanism is close to a plane which passes through the axis of the middle wheel and is vertical to the ground, and e ^ 0;

the differential shaft of the differential mechanism is close to the bottom surface of the carriage, and d ^ 0;

the height of the bottom surface of the carriage from the ground is greater than the diameter of the wheels, and H is greater than D;

the articulated shaft of the rear section of the main rocker arm and the clutch mechanism is positioned on the middle parting line of the connecting line of the middle wheel and the rear wheel₃＝l₆；

The lift height of the jointed shaft is not more than the lift height of the differential shaft, H₁H + d is less than or equal to H, the ground clearance of the articulated shaft is more than the diameter of the wheel H₁＞D；

The diameter of the wheel is larger than zero, and D is larger than 0.

Furthermore, only the horizontal lifting of the carriage is taken as an optimization target, the absolute values of the correlation coefficients of the main rocker arm and the auxiliary rocker arm which meet the objective function rho of alpha and theta approach to each other,

ρ is 1- | r | formula (10)

Drawings

FIG. 1 is a schematic structural diagram of a configuration of an active suspension type planet vehicle moving system according to the present invention;

FIG. 2 is a schematic structural diagram of an included angle adjusting mechanism in an active suspension type planet carrier moving system according to the present invention;

FIG. 3 is a schematic diagram of a rotation included angle between a front section of a main rocker arm and a rear section of the main rocker arm in the configuration of the active suspension type planet vehicle moving system of the invention;

FIG. 4 is a geometric parameter diagram of an active suspension type planet vehicle moving system configuration according to the present invention;

fig. 5 is a geometric parameter diagram of a 0< alpha < pi time configuration in the active suspension type planet vehicle moving system configuration of the invention.

In the drawings, the components represented by the respective reference numerals are listed below:

1. the device comprises a wheel driving mechanism 2, a wheel steering mechanism 3, an included angle adjusting mechanism 4, a clutch mechanism 5, a main rocker arm front section 6, a main rocker arm rear section 7, an auxiliary rocker arm 8, wheels 9 and a carriage.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

As shown in figure 1, the active suspension type planet vehicle moving system configuration optimization design method comprises the steps that a main rocker arm and an auxiliary rocker arm 7 of a suspension are connected with a carriage 9, the planet vehicle moving system comprises two sets of moving system units which are arranged on the suspension and symmetrically arranged at two sides of the carriage 9, each moving system unit comprises a set of included angle adjusting mechanism 3 and three sets of wheel driving mechanisms 1, three sets of wheel steering mechanisms 2 and one set of clutch mechanism 4, the main rocker arm includes front section 5 and rear section 6 of the main rocker arm, the included angle adjusting mechanism 3 is a differential mechanism with single input and double output, two output ends of the differential mechanism are respectively connected with the front section 5 and the rear section 6 of the main rocker arm in a corresponding transmission way, the front section 5 of the main rocker arm is in a transmission way connected with the wheel driving mechanism 1 of the corresponding wheel 8 through the wheel steering mechanism 2, and two ends of the auxiliary rocker arm 7 are respectively in a transmission way connected with the wheel driving mechanism 1 of the corresponding wheel 8 through the corresponding wheel steering mechanism 2; the rear section 6 of the main rocker arm is hinged with the middle part of the auxiliary rocker arm 7 through a clutch mechanism 4;

front of main rocker armAngular variation ω 1 of the segment 5 with respect to the differential mechanism₁Angle variation amount ω 1 of the rear section 6 of the main rocker arm with respect to the output shaft of the differential mechanism₂The difference between the two is the variation delta alpha of the opening angle of the main rocker arm: Δ α ═ ω 1₂-ω1₁In the formula 1, the compound is shown in the specification,

omega 1 when the opening angles of the main rocker arms on the two sides of the carriage 9 are synchronously changed₁That is, the angular variation Δ θ of the front section 5 of the main rocker arm with respect to the vehicle body: Δ θ ═ ω 1₁Formula (2)

By omega 1₂-ω1₁And ω 1₁The ratio of (a) to (b):formula 3

The opening angle of the main rocker arm and the pitching attitude of the carriage 9 are corrected by adopting the above formula, the rod lengths of the front section 5 and the rear section 6 of the main rocker arm are designed to ensure that delta theta and delta alpha are linearly related, and the linear correlation coefficient is just k, so that the differential mechanism can keep the carriage 9 horizontal when the height of the carriage 9 is adjusted.

In some embodiments, the differential mechanism is a planetary gear train, a sun gear in the planetary gear train is fixedly connected with the front section 5 of the main rocker arm, a gear ring is fixedly connected with the rear section 6 of the main rocker arm, and a planet carrier is fixedly connected with the differential shaft.

In some embodiments, correlating Δ θ linearly with Δ α includes:

(1) setting the length l of the front section 5 of the main rocker arm₁Length l of rear section 6 of main rocker arm₂(ii) a Length l of auxiliary rocker arm 7₃(ii) a The included angle alpha between the main rocker arms and the included angle theta between the rear half section 6 of the main rocker arm and the horizontal line; an included angle beta is formed between the front half section and the rear half section of the auxiliary rocker arm 7; the system centroid is offset from the center line by a distance e; wheel spacing l between front wheel and middle wheel₄The wheel spacing l between the middle wheel and the rear wheel₅；

(2) And analyzing the functional relationship among the sizes of the main rocker arm and the auxiliary rocker arm 7: establishing a geometric model, wherein the geometric relations shown in the formulas (4) to (8) are always satisfied among the main rocker arm, the auxiliary rocker arm 7 and the carriage 9 in the adjustment process when the alpha is more than 0 and less than pi:

in the simultaneous expression, theta can be expressed as a function of alpha, the nonlinear relation between alpha and theta is approximately linearized by optimizing design parameters, and the condition that the planetary gear train makes the carriage 9 horizontally lift is met

In some embodiments, the parameter optimization constraints are as follows:

(1) the load of the differential is minimum, the vertical line of the vehicle body center on the flat ground should be as close to the axis of the vehicle body differential as possible, the load of the differential should be as small as possible, certain vertical force is applied to the front end/rear end of the carriage during design, and the rigidity of the differential should ensure that the vehicle body does not generate large pitching.

(2) The inside of the vehicle body is provided with constraint, because a differential and a pivot component penetrate through the whole vehicle body, and the active suspension is introduced into an included angle adjusting mechanism 3, the design ensures that a middle connecting shaft system of the moving mechanism is close to the lower surface of the vehicle body, and a space is reserved for the pivot swinging under the rugged terrain and the included angle adjusting mechanism component. Therefore, the differential is arranged on the lower bottom plate of the vehicle body, and the difference between the height of the axis from the bottom plate and the outer contour of the middle shafting is not too large.

(3) The normal loads of the wheels are uniformly distributed and restrained, the normal loads of the wheels are uniformly distributed as far as possible when the moving mechanism is arranged on the flat ground, and the moving axis is closer in consideration of the difference of the center of mass distance of the vehicle body. The differential axle should therefore be arranged as far as possible above the middle wheel, the front middle wheel and the middle rear wheel being equally spaced in the nominal suspension.

(4) The attitude stability of the vehicle body is restricted, and when the moving mechanism runs in a rough terrain in a nominal state, the terrain smoothness of the main and auxiliary rocker arm type suspension frames is exerted. Therefore, the height of the hinge point of the main rocker arm and the auxiliary rocker arm is not greater than the height of the differential shaft; considering the trafficability requirement, the height of the hinge point of the main rocker and the auxiliary rocker is not lower than the diameter of the wheel from the ground.

(5) The slope static stability is restrained, and the main rocker arm suspension and the auxiliary rocker arm suspension are required to ensure sufficient slope stability. Sufficient stability is provided in view of body lifting and creeping travel on the hill. The distance between the front and rear wheels and the distance between the left and right wheels are set according to the above requirements so that the mass center of the carriage 9 is constantly in a closed area surrounded by the wheel-ground contact points.

(6) The adjustment range of the mass center is most restricted, and the normal load of the wheel 8 may need to be adjusted when the vehicle runs on a slope or gets out of trouble so as to improve the passing performance of the moving mechanism. The implementation capacity of the front wheel and the rear wheel for lifting is closely related to the adjustment of the mass center of the vehicle body. Therefore, when suspension parameters are set, the mass center can be ensured to have a larger adjusting range in front of and behind the middle wheel under the condition that the vehicle body is not unstable. This constraint is also an important basis for estimation of the hill climbing and obstacle crossing stability regions.

(7) The creep advancing step is constrained to the maximum, the lifting height of the vehicle body is limited by considering the stability of the vehicle body, the distance between front wheels and rear wheels of the moving mechanism is limited by the size of the launching cabin, enough distance is reserved between the front wheels and the middle wheels when the terrain is rugged, and the creep advancing step and efficiency are directly influenced by the configuration of the length of the suspension rod. Therefore, the creep step should be increased as much as possible while satisfying the stability of the vehicle body.

(8) The driving moment of the main rocker included angle adjusting mechanism is minimum constrained, and the driving moment of the main rocker included angle adjusting mechanism is required to be as small as possible under the working conditions of nominal suspension (walking, climbing and obstacle crossing), suspension folding and unfolding, wheel lifting, creeping and advancing and the like, so that the driving power of the included angle adjusting mechanism and the volume and mass of the speed reducing mechanism are reduced.

(9) The driving torque of the main rocker arm clutch mechanism and the auxiliary rocker arm clutch mechanism is minimum constrained, the clutch works when the wheels 8 are lifted and walk, the reasonable planning of suspension parameters is beneficial to reducing the driving torque of the clutch mechanism under relevant working conditions, and the driving power, the quality and the volume of the clutch mechanism are effectively reduced.

In some embodiments, the primary and secondary rocker arms 7 and the differential mechanism are designed to satisfy the following conditions:

the distance between the front wheel and the middle wheel in the planet vehicle moving system is equal to the distance between the middle wheel and the rear wheel₄＝l₅；

A differential shaft of the differential mechanism is close to a plane which passes through the axis of the middle wheel and is vertical to the ground, and e ^ 0;

the differential axis of the differential mechanism is close to the bottom surface of the vehicle compartment 9, and d ^ 0;

the height of the bottom surface of the carriage 9 from the ground is greater than the diameter of the wheels 8, and H is greater than D;

the articulated shaft of the rear section 6 of the main rocker arm and the clutch mechanism 4 is positioned on the middle parting line of the connecting line of the middle wheel and the rear wheel₃＝l₆；

The lift height of the jointed shaft is not more than the lift height of the differential shaft, H₁H + d is less than or equal to H, the ground clearance of the articulated shaft is more than the diameter of the wheel 8, H₁＞D；

The diameter of the wheel 8 is larger than zero, and D is larger than 0.

In some specific embodiments, only with the horizontal lifting of the carriage 9 as an optimization target, the absolute value of the correlation coefficient of the main and auxiliary rocker arms satisfying the objective functions p of alpha and theta approaches to 1,

ρ is 1- | r | formula (10)

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.