WO2019091442A1

WO2019091442A1 - Pantograph head balancing structure of pantograph having small rotation angle, pantograph head and design method thereof

Info

Publication number: WO2019091442A1
Application number: PCT/CN2018/114692
Authority: WO
Inventors: 王先锋; 袁文辉; 蒋忠城; 张彦林; 冯叶; 陈敏坚
Original assignee: 中车株洲电力机车有限公司
Priority date: 2017-11-09
Filing date: 2018-11-09
Publication date: 2019-05-16
Also published as: DE112018005307T5; DE112018005307T9

Abstract

A pantograph head balancing structure of a pantograph having a small rotation angle, a pantograph head and a design method thereof. The method optimizes the rotation angle of a pantograph head by means of relative position parameter coordinates of hinge points of a pantograph, well developed dynamics software, and an integrated database of general optimization algorithms, so as to significantly reduce a declination angle of the pantograph head, such that the pantograph head achieves a state of near horizontal motion within a working range of the raising and lowering of the pantograph. The invention increases the surface area of contact between the pantograph and a catenary, thereby improving the quality of a current collected by the pantograph, and reducing damage to the pantograph and the catenary.

Description

Small angle pantograph bow head balance mechanism, bow head and design method thereof

Technical field

The invention relates to the technical field of rail vehicle pantograph, in particular to a small corner pantograph bow head design method.

Background technique

When the single carbon skateboard pantograph is in contact with the contact net, the contact area is easily affected by the relative angle of the contact line between the carbon slide and the contact net of the pantograph head. Since the contact net is a stationary device and the vehicle is a mobile device, the contact height of the contact net contact line changes with respect to the vertical height of the vehicle during the movement of the vehicle, thereby causing a change in the working height of the pantograph, thereby causing the carbon slide to be opposite to the contact line. The angle changes. When the deflection angle of the carbon head slide is large, the contact between the single carbon slide and the contact net changes from point contact to point contact, and the contact stress at the contact point increases sharply, which easily causes the contact line to bend, greatly increasing the mechanical friction and increasing. Contact resistance, which causes the temperature at the contact point to rise sharply, causing the quality of the bow network to drop sharply, and it is easy to burn the carbon slide and the contact net.

Figure 1 and Figure 2 show a single carbon skateboard pantograph structure previously designed by the company, including an upper arm, a lower arm, a tie rod, a bow head, and a balance bar system for balancing the bow head, the balance bar system a first rod 3 hinged to the upper end of the lower arm 2, a second rod 4 hinged to the upper end of the upper arm 1, a fourth rod 6 hinged to the bow shaft 7, and one end hinged to the free end of the second rod 4 and a third rod 5 hinged at one end to the free end of the fourth rod 6; the other end of the first rod 3 is hinged to the middle of the second rod 4, and the upper end of the upper arm rod 1 is extended with a connecting portion 8, the connecting portion 8 and The bow head shaft 7 is hinged.

The hinge point of the lower arm 2 and the first rod 3 is E, the hinge point of the first rod 3 and the second rod 4 is J, the hinge point of the upper arm rod 1 and the second rod 4 is F, and the second rod 4 and the The hinge point of the three rods 5 is G, the hinge point of the third rod 5 and the fourth rod 6 is I, and the joint point of the joint portion 8 and the bow shaft 7 is K. [See Figure 1(b)]

The pantograph structure has a maximum deflection angle of 10.7 degrees in the process of the bow movement, which is much larger than the standard value. The deflection angle curve is shown in Fig. 3. This will seriously affect the quality of the pantograph.

According to the requirements of the high-speed railway for high-speed pantographs at home and abroad, the bow balance mechanism must be less than ±2° in the range of the minimum height of the pantograph slide from 300mm to the maximum height of 2400mm. Therefore, the modern pantograph has a bow balance mechanism that allows the bow carbon slide to maintain a small angular deflection over the working height range. At present, the bow balance mechanism of the pantograph includes the main structure of the pantograph (

components

1, 2, 9, 10, 11 and hinges J1-J5 in the figure) and has at most one balance bar. On the one hand, it is difficult to find better optimization parameters to keep the bow head at a small angle, and on the other hand, the main structure of the pantograph is restricted, so that its working range, contact force of the net and driving parameters are more restricted. The performance of the bow is greatly reduced. Even if the pantograph is designed by simple optimization analysis such as CAD, the bow angle may still be large, and the maximum may exceed 10 degrees, which is much larger than the standard value. The deflection angle curve is shown in Figure 3. This will seriously affect the pantograph. Flow quality.

In the actual design and optimization process of the pantograph, the initial plan of the pantograph is usually made in the 2D CAD software, and the size and angle of the main motion mechanism of the pantograph are parameterized, and the parameters are listed. The geometric and kinematic equations of the relationship are shown in Figure 4. The language tools such as FORTRAN and C are used to solve the equations, and then the optimization algorithm is used to optimize the calculation of the bow angle.

It can be seen from Fig. 4 that there are many parameters, and it must contain the parameters of the main structure. The equations contain nonlinear functions including sine, cosine, and tangent. The equation solving algorithm and programming are complicated, especially when adding a rod. The topology of the program has changed completely. The whole calculation and analysis process has a long cycle, the equation solving algorithm and the optimization algorithm are inefficient, and the algorithm is unstable. When the initial condition distance limit of the pantograph is large, it is difficult to obtain the structural optimization solution quickly and efficiently, especially When the design variables or the related constraints on the size of the main structure are more stringent, it is unlikely to obtain an optimized solution of the structure.

In this way, it is necessary to add more balance bars, to meet the requirements of the bow angle of the bow and to reduce the restriction on the main structure of the pantograph, so that the topology and the algorithm of the program are completely changed, and the difficulty of programming and debugging is greatly increased. The design cycle is long, and most of the time is spent on programming and algorithms, and the performance analysis of the pantograph itself is small. In addition, the optimization algorithm only optimizes under given initial conditions, and is generally only a local optimization solution of the structure, rather than a global optimization solution.

The parameters such as the size and angle of the main motion mechanism of the pantograph are optimized. In fact, the position of the hinge points of the pantograph is optimized to meet the requirements of the corner of the bow.

To define the vocabulary of the directions mentioned in this case, in the field of rail vehicles, there are three directions that technicians usually identify:

Vertical: Vertically perpendicular to the direction of the rail surface.

Portrait: The direction along the track.

Landscape: Horizontally perpendicular to the direction of the track.

Summary of the invention

The technical problem to be solved by the present invention is that, in view of the deficiencies of the prior art, a small angle angle pantograph bow head balancing mechanism, a bow head and a design method thereof are provided, which have a small bow angle and a good flow quality, and a pantograph The position of each hinge point is optimized to meet the requirements of the corner of the bow.

In order to solve the above technical problem, the technical solution adopted by the present invention is: a small-angle pantograph bow head balancing mechanism, including a balance bar system, the balance bar system including a first rod and an upper arm hinged to an upper end of the lower arm a second rod hinged at an upper end of the rod, a fourth rod fixedly connected to an intermediate position of the bow shaft, a third rod hinged at one end to the free end of the second rod and the other end hinged to the free end of the fourth rod;

The first rod is disposed directly below the upper arm, the other end of the first rod is hinged with the middle of the second rod, and the upper end of the upper arm extends with a connecting portion, the connecting portion is hinged with the bow shaft, the second rod a curved rod whose bending direction is toward the first rod;

The upper arm, the lower arm, the first rod, the second rod, the third rod and the fourth rod are on the same vertical plane, and the hinge point F of the upper arm and the second rod on the vertical plane is a coordinate The origin, the longitudinal direction is the X axis, and the vertical direction is the Z axis to establish a plane coordinate system;

The J coordinate of the hinge point of the first rod and the second rod is (X _j , Z _j ), and the coordinates of the hinge point G of the second rod and the third rod are (X _g , Z _g ), and the third rod and the fourth rod The coordinate of the hinge point I is (X _i , Z _i ), and the coordinate of the fixed point H of the fourth rod and the bow shaft is (X _h , Z _h );

Wherein, 20≤X _j ≤90, -80≤Z _j ≤-20; 10≤X _g ≤100, -160≤Z _g ≤-80; 150≤X _i ≤230, -230≤Z _i ≤-150; 146≤X _{_h} ≤206, -60≤Z _h ≤0.

Preferably, the J coordinate of the hinge point of the first rod and the second rod is (56.3, -64.4), and the coordinates of the hinge point G of the second rod and the third rod are (38.6, -141.1), and the third rod and the fourth rod The coordinate of the hinge point I of the rod is (206.4, -205.1), and the coordinate of the fixed point H of the fourth rod and the bow shaft is (176.5, -27.8), and the unit is mm.

When the pantograph slide changes from a minimum height of 300 mm to a maximum height of 2400 mm, the deflection angle of the bow head ranges from -0.71 ° to 0.71 °. This deflection angle is within ±2° of the standard design and is above the standard.

The bow shaft has a π-shaped structure, and comprises a hollow intermediate tube, a curved arc section fixedly connected with the tube wall at both ends of the intermediate tube, and two ends of the curved section are connected with the elastic buffer device;

The connecting portion is a pair of connecting rods fixed to the upper end of the upper arm and symmetrically disposed with respect to the vertical plane. The connecting rod and the upper arm shaft form a Y-shaped structure, and the connecting rod ends are hinged to the two ends of the intermediate tube one by one. .

Accordingly, the small-angle pantograph bow head of the present invention includes the above-described balance mechanism.

As an inventive concept, the present invention also provides a small corner pantograph bow design method comprising the following steps:

1) Establish a non-parametric pantograph dynamics model in the kinetic software;

2) Based on the minimum working height position of the skateboard in the vertical motion plane of the pantograph, parameterize the position of the pantograph optimized hinge: the reference hinge is used to optimize the origin of the local coordinate system of the hinge, and the relative coordinate represents the optimized hinge For the relative position of the reference hinge, a parameterized representation of the optimized hinge position is performed;

3) For the optimized hinge in the non-parametric pantograph dynamics model established in step 1), the relative coordinates of the hinge position to the reference hinge position in step 2) are used as parameters to establish the parametric power of the pantograph for optimizing the hinge. Learning model

4) setting the relative coordinate parameter of the above optimized hinge as the design variable of the bow angle optimization;

5) Obtain the bow angle response curve of the bow raising process when the pantograph is raised to the maximum working height of the skateboard in the dynamic software, and obtain the maximum value of the bow head angle response curve.

And minimum

Define the change angle of the bow angle:

The change amplitude of the bow head angle is defined as the objective function of the bow head angle optimization;

6) Minimize the objective function optimized by the bow angle

In order to optimize the target, the parametric dynamic model of the pantograph of the optimized hinge is optimized and solved, and the corner optimization scheme of multiple pantograph hinge position design variables is obtained.

7) Using the multiple corner optimization schemes obtained in step 6) to perform interference analysis and maximum working height analysis of the components of the pantograph, verify the conflict of the pantograph motion state, and obtain the pantograph bow angle, component interference, and range of motion. According to the comparative analysis of the advantages and disadvantages, the scheme of the pantograph bow angle, component interference and motion range satisfying the technical requirements of the pantograph is obtained, and the scheme of selecting the minimum corner of the pantograph head is the best solution. .

If the above solution does not meet the requirements of the pantograph technical requirements, the balance bar is added to increase the connection hinge, and the increased connection hinge position is the same parameterized representation as step 2), and steps 3) to 7) are repeated. Until the corner of the pantograph bow meets the technical requirements.

In step 5), the maximum value of the bow angle response curve is obtained by the maximum and minimum processing functions of the kinetic software.

And minimum

Compared with the prior art, the present invention has the beneficial effects that the balance mechanism of the present invention changes the relative position of the rotating hinges of the rod members of the pantograph balancing system, so that the deflection angle of the bow head in the working range is 10.7 degrees. Reduced to 0.71°, controlled within the 2° standard range; by significantly reducing the deflection angle of the bow, the contact area of the pantograph and the rigid contact net is increased, which effectively improves the quality of the pantograph and reduces the flow quality. Bow net damage; the present invention is directed to the current single-carbon skateboard pantograph bow head deflection angle is large, the programming amount is large, the equation solving algorithm and the optimization algorithm are low in efficiency, slow in speed, difficult to converge, etc., which easily cause the pantograph to have a large rotation angle. The actual background of the flow quality is significantly reduced. An optimized design method of the small-angle pantograph bow head is proposed. The position of each hinge point of the pantograph is optimized to meet the requirements of the bow head angle. The invention uses the method of relative position parameter coordinates of the pantograph hinge point, and uses the mature dynamic software and the integrated general optimization algorithm library to optimize the corner of the bow head, so that the deflection angle of the pantograph bow head is significantly reduced, so that The bow head reaches an almost translational state within the working range of the lifting bow, which increases the contact area between the pantograph and the contact net, effectively improving the flow quality of the pantograph and reducing the damage of the arch net. Specifically, the bow design method of the present invention has the following features and advantages:

(1) Directly adopting the two-dimensional spatial relative coordinate parameters of each hinge position of the pantograph to select parameters, and defining the optimal design variables with reference hinge and relative coordinates to optimize the bow angle;

(2) It is no longer necessary to compile the geometric equations and motion equations of the pantograph. It is no longer necessary to program and debug the equation solving algorithm and optimization algorithm, saving a lot of programming and debugging time, and modifying or adding parameters is simpler and more efficient;

(3) The kinetic software and optimization algorithm are mature and reliable, and the optimization of the bow head balance mechanism is fast and effective. Generally, the optimized small-angle bowhead pantograph can be obtained in 1-2 hours.

(4) Data integration into a model, the parametric dynamic model of the pantograph can more fully reflect the dynamic performance of driving, interference, corner, etc. The structure geometry, dynamic state and other clear, visible, data-rich, direct verification components Core performance such as interference and working range;

(5) Engineering optimization of multiple optimization schemes of design variable parameters, maximizing the performance of pantograph and avoiding local optimization results, and obtaining a global optimization solution with practical engineering significance;

(6) It is easier to extend and derive the pantograph of the new structure. It is simple and effective to add one or more hinge position optimization points and relative coordinate parameters only to the pantograph model.

DRAWINGS

(a) and (b) of Fig. 1 are plan views of a prior art pantograph;

The corresponding relationship of the hinge points

图1(a)Figure 1 (a)	图1(b)Figure 1 (b)
J6J6	EE
J7J7	FF
J8J8	JJ
J9J9	GG
J10J10	II

2 is a perspective view of a prior art pantograph.

Fig. 3 is a graph showing the variation of the deflection angle of the pantograph head of the prior art.

Figure 4 shows the current pantograph principle model and its optimization parameters and equations;

Figure 5 is a structural view of a pantograph of the present invention.

Figure 6 is an enlarged view of the structure of the bow head of Figure 3.

Figure 7 is a perspective view of the bow head structure of the present invention.

Figure 8 is a parametric example of the rotation hinge of a single carbon skateboard pantograph bow head (minimum working height, the dotted hinge is the optimized position of the original rotating hinge);

Figure 9 is an optimized bow angle curve (example);

among them:

1. Upper arm, 2, lower arm, 3, first rod, 4, second rod, 5, third rod, 6, fourth rod, 7, bow head shaft, 8, connecting portion, 71, middle tube , 72, curved section, 81, connecting rod, 9, chassis, 10, drawbar, 11, bow head, J1 ~ J10 - rotating hinge.

Detailed ways

As shown in Figures 5-7, a small angle pantograph bow balance mechanism includes a balance bar system including a first rod 3 hinged to the upper end of the lower arm 2 and hinged to the upper end of the upper arm 1 The second rod 4, the fourth rod 6 fixedly connected to the intermediate position of the bow shaft 7, the third rod 5 whose one end is hinged to the free end of the second rod 4 and whose other end is hinged to the free end of the fourth rod 6.

The first rod 3 is disposed directly below the upper arm 1, and the other end of the first rod 3 is hinged to the middle of the second rod 4. A connecting portion 8 is extended at the upper end of the upper arm 1, and the connecting portion 8 is hinged to the bow shaft 7. The second rod 4 is a curved rod whose bending direction is toward the first rod 3.

The bow shaft 7 has a π-shaped structure, and includes a hollow intermediate tube 71, and a curved arc portion 72 fixedly connected to the tube wall at both ends of the intermediate tube 71. Both ends of the curved portion 72 are connected to the elastic buffer device.

The connecting portion 8 is a pair of connecting rods 81 fixed to the upper end of the upper arm 1 and symmetrically disposed with respect to the vertical plane. The connecting rod 81 and the upper arm rod 1 together form a Y-shaped structure, and the ends of the connecting rod 81 are hinged in one-to-one correspondence with the two ends of the intermediate tube 71.

The upper arm 1, the lower arm 2, the first rod 3, the second rod 4, the third rod 5, and the fourth rod 6 are on the same vertical plane. On the vertical plane, the hinge point F of the upper arm 1 and the second rod 4 is the coordinate origin, and the X-axis in the longitudinal direction and the Z-axis in the vertical direction establish a plane coordinate system.

The J coordinate of the hinge point of the first rod 3 and the second rod 4 is (X _j , Z _j ), and the coordinates of the hinge point G of the second rod 4 and the third rod 5 are (X _g , Z _g ), and the third rod The coordinates of the hinge point I of the fifth rod 6 and the fourth rod 6 are (X _i , Z _i ), and the coordinates of the fixed point H of the fourth rod 6 and the bow shaft 7 are (X _h , Z _h ).

Preferably, the J coordinate of the hinge point of the first rod 3 and the second rod 4 is (56.3, -64.4), and the coordinates of the hinge point G of the second rod 4 and the third rod 5 are (38.6, -141.1), and the third The coordinates of the hinge point I of the rod 5 and the fourth rod 6 are (206.4, -205.1), and the coordinates of the fixed point H of the fourth rod 6 and the bow shaft 7 are (176.5, -27.8), and the unit is mm. As shown in Fig. 7, the deflection angle of the bow head obtained by the preferred scheme has a deflection angle which is within ±2° of the standard design and is higher than the standard.

The specific optimization steps of the small corner pantograph bow head of the present invention are as follows:

(1) Establish a non-parametric pantograph dynamics model in general dynamics software (such as SIMPACK, RECURDYN, ADAMS, etc.) according to the pantograph design. Based on the initial graphical geometry of existing 3D CAD software (such as UG, etc.), the pantograph scheme of Figure 1 is taken as an example to illustrate the process of establishing a nonparametric pantograph dynamics model.

Create the parts and their geometry of the non-parametric pantograph dynamics model, and enter the three-dimensional geometry of each component (1, 2, 3, 4, 5, 9, 10, 11) in turn in the dynamics software, if a component is For several parts, the parts of this part are combined in the dynamic software to form the same Part (software terminology). The software will select the part's material as steel by default, and select the material in the software library or directly assign it to Part. Weight, the software automatically calculates the weight, center of gravity and moment of inertia of the part based on the part material.

The motion hinge of the non-parametric pantograph dynamics model is established. In the dynamic software, the type of hinge, the connected parts and the position of the hinge are selected according to each specific motion hinge. The motion hinges illustrated in Fig. 1 are all rotating hinges. The components connected by the hinge J1 in Fig. 1 are the chassis 10 and the lower arm 2, and the position is the rotation center of the bearing connected to the chassis 1 or the lower arm 2 and its axis, Fig. 1 The parts connected by the middle hinge J2 are the lower arm rod 2 and the upper arm rod 1, and the position is the rotation center and the axis of the lower arm rod 2 and the upper arm rod 1 connected to the bearing, and the other hinges J3-J10 are according to the respective connecting parts and their rotation centers. Established separately in the dynamics software.

Apply a low-speed uniform rotation drive to the lower arm of the pantograph and the chassis drive hinge, first calculate an approximate simulation calculation time, and then determine the final simulation calculation time according to the pantograph motion to the maximum working height. The software automatically generates and solves the kinematic equations of the pantograph to avoid column, programming, and solving the equations. The software automatically generates time-dependent results such as the position of each component, the angle of rotation, and so on. One of the core indicators of the single carbon skateboard pantograph is the bow angle of the bow head 11 in the pantograph moving from the minimum working height to the maximum working height. The corner curve of the bow head 11 can be obtained by the software self-contained function, as shown in the figure. The curve of 3 is shown.

(2) Parameterize the position of the pantograph rotating hinge. Based on the initial solution position in the two-dimensional plane of the motion plane of the pantograph, the rotational hinge position is parameterized with relative coordinates.

The position of each rotating hinge of the pantograph can be parameterized. If it is not necessary to change the motion performance of the main structure of the pantograph, such as the maximum working height of the pantograph and the raising moment, the rotation of the main structure is not required. The position of the hinge is parameterized, and only the position of the hinge of the balance bar is parameterized. Taking the example of Fig. 1, the parameterization process of the position of the rotating hinge is illustrated, as shown in Fig. 8. The rotational hinge parameterization example is shown in Fig. 1 (the main body is the

components

1, 2, 9, 10, 11 and the hinges J1-J5, and the

components

3, 4, 5 and the hinges J7-J10 are specific balancing mechanisms for maintaining the corner of the bow. The parametric processing example of the position of the rotating hinge assumes that the technical requirements of the pantograph in addition to the corner of the bow are satisfied, and thus the rotating hinge of the main structure (J1-J5 in Fig. 1) is not selected.

Table 1 Definition of the geometric dimensions of the pantograph

Where x _E and y _E are functions of design variables L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , a, b, γ.

The translational equation of motion of the bow head (the angle between the bow head and the horizontal direction)

Where x _F and y _F are the coordinates of point F, that is, x _F = L ₇ cos λ - L ₂ cos (α - μ), y _F = L ₇ sin λ + L ₂ sin (α - μ). ρ is a function of the design variables L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , L ₆ , L ₇ , a, b, γ.

For the pantograph structure of the example of FIG. 1, the rotating hinge of the balancing mechanism (J8-J10 in FIG. 1) is selected for parameterization processing, and the components connected to the rotating hinge J7 in FIG. 1 are the upper arm 1 and the component balance bar ( The first rod 3), the upper arm 1 is a main structure, and its size is not changed, so the position of the hinge J7 relative to the upper arm 1 does not change, and the hinges J8 and J9 connected to the first rod 3 need to change their relative sizes, In order to meet the requirements of the bow angle, the positions of J8 and J9 are referenced to J7. The initial scheme of the first rod 3 is a straight length member, and the hinges J8 and J9 are all located on the member. Therefore, the length of the first rod 3 in the longitudinal direction is the longitudinal direction, and the dimension in the vertical direction y direction is the position of the parameters J8 and J9. The position of the hinges J8 and J9 is parameterized.

J8(O) in Fig. 8 is the position of the initial scheme of the hinge J8 in Fig. 1, J8(N) is the new position after the position of the hinge J8 is changed, and the distance between J8(N) and J7 in the x direction is L1, in the y direction. The distance is H1. Similarly, J9(O) is the position of the initial plan of hinge J9 in Fig. 1, J9(N) is the new position after the position of hinge J9 changes, and the distance between J9(N) and J7 in the x direction is L2, the distance in the y direction For H2. Similarly, J10 uses J3 as a reference to define the positional parameters L3, H3 of J10 with reference to J3.

(3) Parameterize the non-parametric dynamic model established in the first step, define the parameters defined in step 2 and the position of the corresponding hinge, and establish a parametric dynamic model of the pantograph to optimize the hinge. The process of the parametric kinetic model is illustrated by the pantograph scheme illustrated in Figure 1 and the parameters defined in Figure 8.

Six parameters are established in the kinetic software, L1, L2, L3, H1, H2, H3, and the initial values are set according to the initial scheme. A marker point P7 (Marker) is defined at the J7 reference hinge center position. The marker point coordinate system is consistent with the reference direction in FIG. 3, and then the center marker point P8 of J8 is defined as a parameter point, and the reference point of P8 is selected as P7, P8 coordinates. The reference direction is automatically coincident with P7, the distance of P8 in the x direction of the P7 marker point is L1, and the distance in the y direction is H1. Similarly, the J9 center identification point P9 is set as the parameter point and the central identification point P10 of J10 is the parameter point, where P7 is the reference point and coordinate reference direction of P9, and the J3 center identification point P3 is the reference point of P10 and the coordinate reference direction. P8, P9, P10 and the position change verification, that is, by changing the values of L1, L2, L3, H1, H2, H3, observe whether the positions of P8, P9, P10 and their hinges J8, J9, J10 change accordingly. The pantograph dynamics model of parameterized changes in the hinge positions J8, J9, and J10 of the parameters L1, L2, L3, H1, H2, and H3 is completed.

(4) In the software, the rotational joint relative position parameter in the parametric dynamic model of parameterization in step 3 is set as the design variable of the bow angle optimization. On the basis of the preliminary analysis of the first step, the motion state and the interference state of the mechanism are analyzed, and the initial value and the range of variation of the design parameters of the rotational hinge position are set. For the examples of Figures 1 and 8, the parameters can be as shown in Table 2.

Table 2 The initial value and range of variation of the design parameters of the rotary hinge position

(5) Perform the maximum and minimum values on the response curve of the bow angle obtained in the first step, and define the difference between the maximum and minimum values of the bow angle of the bow head. The angle range is the objective function. Minimize to optimize the goal.

For (4) and (5), if there is no integrated optimization calculation module in the dynamic software, the calculation text file of the dynamic model is extracted, and the optimization parameters, the objective function and the optimization target can be optimized in the general optimization software for software such as Isight and Optimus. Settings and optimization solutions.

(6) Optimize and solve the parameterized pantograph dynamics model of the hinge point defined in step 3 in the general dynamics software or general multidisciplinary optimization software of the integrated optimization calculation module algorithm library. The corner optimization scheme of the design parameter variable of the pantograph hinge position.

(7) Analyze the multiple optimization schemes obtained in step 6, select some of the optimization schemes, and use the software to drive the rapid change of the third parametric hinge position pantograph dynamics model to perform the pantograph name components. Analysis of interference analysis, maximum working height, etc., quickly verify the interference of the pantograph motion state such as component interference and insufficient working range, and quickly and efficiently obtain the engineering performance of the pantograph bow angle, component interference, motion range, etc. Inferior comparative analysis.

Steps (2)-(7) may be repeated to increase the optimized hinge-related position corresponding parameters, or to optimize the hinge position parameters of the main body mechanism and to increase the optimization design variables such as the balance bar component and its hinge position parameters to expand and derive the The new design of the electric bow until a satisfactory small corner bow mechanism is obtained.

For the pantograph structure of the example of Fig. 1, the optimization parameters in Table 2 can significantly reduce the deflection angle range from -0.71 to 0.71 °, as shown in Fig. 9, which can well meet the engineering requirements such as the bow angle.

Claims

A small-angle pantograph bow balance mechanism includes a balance bar system including a first rod (3) hinged to an upper end of the lower arm (2) and a second hinged to an upper end of the upper arm (1) a rod (4), a fourth rod (6) fixedly connected to an intermediate position of the bow shaft (7), one end hinged to the free end of the second rod (4) and the other end and the free end of the fourth rod (6) Articulated third rod (5);

The first rod (3) is disposed directly below the upper arm (1), the other end of the first rod (3) is hinged to the middle of the second rod (4), and the upper end of the upper arm (1) is extended with a connecting portion (8), the connecting portion (8) is hinged with the bow shaft (7), characterized in that: the second rod (4) is a curved rod, the bending direction of the first rod (3);

The upper arm (1), the lower arm (2), the first rod (3), the second rod (4), the third rod (5), and the fourth rod (6) are on the same vertical plane, The hinge point F of the upper arm (1) and the second rod (4) on the vertical plane is the coordinate origin, the longitudinal direction is the X axis, and the vertical direction is the Z axis to establish a plane coordinate system; the first rod (3) and the second rod The J coordinate of the hinge point of the rod (4) is (X j , Z j ), and the coordinates of the hinge point G of the second rod (4) and the third rod (5) are (X g , Z g ), and the third rod ( 5) The coordinate of the hinge point I with the fourth rod (6) is (X i , Z i ), and the coordinates of the fixed point H of the fourth rod (6) and the bow shaft (7) are (X h , Z h );

Wherein, 20≤X j ≤90, -80≤Z j ≤-20; 10≤X g ≤100, -160≤Z g ≤-80; 150≤X i ≤230, -230≤Z i ≤-150; 146≤X h ≤206, -60≤Z h ≤0.
The small-angle pantograph bow balance mechanism according to claim 1, wherein the hinge point J coordinate of the first rod (3) and the second rod (4) is (56.3, -64.4), and the second rod (4) The coordinates of the hinge point G with the third rod (5) are (38.6, -141.1), and the coordinates of the hinge point I of the third rod (5) and the fourth rod (6) are (206.4, -205.1) The coordinates of the fixed point H of the fourth rod (6) and the bow shaft (7) are (176.5, -27.8), and the unit is mm.
The small-angle pantograph bow balance mechanism according to claim 1 or 2, wherein the bow shaft (7) has a π-shaped structure including a hollow intermediate tube (71) and a middle tube (71). a curved arc segment (72) to which the tube walls at both ends are fixedly connected, and both ends of the curved arc segment (72) are connected to the elastic buffer device;

The connecting portion (8) is a pair of connecting rods (81) fixed to the upper end of the upper arm (1) and symmetrically disposed with respect to the vertical plane, and the connecting rod (81) and the upper arm (1) shaft together form a Y shape The structure, the end of the connecting rod (81) is hinged in one-to-one correspondence with the two ends of the intermediate tube (71).
A small-angle pantograph bow head comprising the balance mechanism of any one of claims 1 to 3.
A small corner pantograph bow head design method, characterized in that the method comprises the following steps:

1) Establish a non-parametric pantograph dynamics model in the kinetic software;

2) Based on the minimum working height position of the skateboard in the vertical motion plane of the pantograph, parameterize the position of the pantograph optimized hinge: the reference hinge is used to optimize the origin of the local coordinate system of the hinge, and the relative coordinate represents the optimized hinge For the relative position of the reference hinge, a parameterized representation of the optimized hinge position is performed;

3) For the optimized hinge in the non-parametric pantograph dynamics model established in step 1), the relative coordinates of the hinge position to the reference hinge position in step 2) are used as parameters to establish the parametric power of the pantograph for optimizing the hinge. Learning model

4) setting the relative coordinate parameter of the above optimized hinge as the design variable of the bow angle optimization;

5) Obtain the bow angle response curve of the bow raising process when the pantograph is raised to the maximum working height of the skateboard in the dynamic software, and obtain the maximum value of the bow head angle response curve.
And minimum
Define the change angle of the bow angle:
The change amplitude of the bow head angle is defined as the objective function of the bow head angle optimization;

6) Minimize the objective function optimized by the bow angle
In order to optimize the target, the parametric dynamic model of the pantograph of the optimized hinge is optimized and solved, and the corner optimization scheme of multiple pantograph hinge position design variables is obtained.

7) Using the multiple corner optimization schemes obtained in step 6) to perform interference analysis and maximum working height analysis of the components of the pantograph, verify the conflict of the pantograph motion state, and obtain the pantograph bow angle, component interference, and range of motion. According to the comparative analysis of the advantages and disadvantages, the scheme of the pantograph bow angle, component interference and motion range satisfying the technical requirements of the pantograph is obtained, and the scheme of selecting the minimum corner of the pantograph head is the best solution. .
The method according to claim 5, wherein in the step 1), the process of establishing the non-parametric pantograph dynamics model comprises: sequentially inputting the three-dimensional geometry of the components of the pantograph in the dynamic software, if A component consists of several parts, and the parts of the part are combined in the dynamic software to form the same part; in the dynamic software, the type of the hinge, the connected parts and the position of the hinge are selected according to each specific movement hinge; A uniform rotational drive is applied to the lower arm of the pantograph and the driving hinge of the chassis, and the final simulation calculation time is determined according to the time of the pantograph moving to the maximum working height. The dynamic software generates the kinematic equation of the pantograph and solves it. The dynamics software generates the position and rotation angle of each component related to the simulation calculation time according to the solution result.
The method according to claim 5, wherein the balance bar is added to increase the connection hinge, and the position of the added connection hinge is the same as that of step 2), and steps 3) to 7) are repeated. Until the pantograph bow angle meets the technical requirements.
The method according to claim 5, wherein in step 5), the maximum value of the bow angle response curve is obtained by the maximum and minimum processing functions of the kinetic software.
And minimum