Optimization method of dual-drive toggle rod mechanism
1. A method for optimizing a dual drive toggle mechanism is characterized by comprising the following steps:
step 1, determining basic structural parameters of a dual-drive toggle rod working mechanism according to the overall design requirements of a press, and dividing the whole mechanism into an upper toggle rod part and a lower toggle rod part;
step 2, setting structural parameters of the lower elbow rod part according to the maximum total height of the toggle rod mechanism of the press, and assuming that the initial structure of the lower elbow rod part is an isometric toggle rod structure;
step 3, on the basis of the set structural parameters of the lower toggle rod part, taking the upper toggle rod part and the lower toggle rod part as a whole, setting the constraint conditions of the parameters of the upper toggle rod mechanism by taking the driving torque as an optimization target and the parameters of the upper toggle rod mechanism as optimization variables, and performing structural optimization on the dual-drive toggle rod working mechanism to obtain the optimized structural parameters of the upper toggle rod part;
step 4, on the basis of the structural parameters of the upper toggle rod part obtained in the step 3, taking the upper toggle rod part and the lower toggle rod part as a whole, taking the driving torque as an optimization target, taking the parameters of the lower toggle rod mechanism as optimization variables, and setting the constraint conditions of the parameters of the lower toggle rod mechanism, performing mechanism optimization of the dual-drive toggle rod working mechanism to obtain the optimized structural parameters of the lower toggle rod part;
and 5, changing the rod length constraint condition in the step 3, repeatedly performing iterative structure optimization in the step 3 and the step 4, and finally obtaining the optimized structure parameters of the whole mechanism after the driving torque optimized target value tends to be stable and unchanged.
2. The method for optimizing a dual drive toggle linkage mechanism according to claim 1, wherein the basic parameters of step 1 include: nominal pressure, nominal pressure stroke, total stroke, maximum total height of the press, maximum total width of the press, and length of each crank, connecting rod, and toggle rod.
3. The method for optimizing a dual drive toggle mechanism according to claim 1, wherein in step 2, the two toggle links of the lower toggle link portion are equal in length and are set to be one third of the maximum overall height of the mechanism, and the two toggle links are collinear, and the length of the connecting rod and the toggle link of the lower toggle link portion are equal, the crank of the lower toggle link portion is one third of the connecting rod, the crank and the connecting rod are collinear, and the included angle between the connecting rod and the toggle link is 90 degrees.
4. The optimization method of a dual drive toggle link mechanism according to claim 1, wherein the maximum length of the toggle links of the upper toggle link section in step 3 is set to be one third of the maximum overall height of the mechanism, the maximum length of the connecting rods of the upper toggle link section is equal to the maximum length of the toggle links, and the maximum length of the cranks of the upper toggle link section is set to be one third of the maximum length of the toggle links.
5. The method for optimizing a dual drive toggle link mechanism according to claim 1, wherein the constraint conditions in step 4 are: the maximum rod length of the two toggle links of the lower toggle link part is respectively The maximum rod length of the lower toggle link part connecting rod is l2max=l4maxThe maximum rod length of the crank of the lower toggle link part isObtaining optimized mechanism parameters of the lower toggle link part; wherein l2max=l4maxIn which K is1、K2The value range of (1) to (1.2) and H is the maximum total height of the mechanism.
6. The method of optimizing a dual drive toggle linkage mechanism according to claim 1,the maximum rod length of the upper toggle link part connecting rod in the step 5 is l5max=H-l4-l6And H is the maximum total height of the mechanism.
7. The method for optimizing a dual drive toggle link mechanism according to claim 1, wherein the step 5 is performed under the condition that the torque objective function value obtained in the step tends to be stableWherein XiRepresenting the value of the torque objective function, X, obtained in the present stepi-1And representing all the optimized parameters finally obtained by the torque objective function values obtained in the previous step.
Background
Mechanical presses are one of the most important metal forming equipment, and one of the most important, toggle mechanical presses is one of the main types. The toggle rod type mechanical press has the characteristics of low working stroke speed, large reinforcement ratio, long pressure maintaining time of the slide block at the bottom dead point and the like, has good rigidity of a machine body, is suitable for metal precision press forming or extrusion forming, and is widely applied to the industries of machinery, automobiles, instruments and meters and the like.
The motion diagram of the working mechanism of the traditional toggle rod type mechanical press is shown in fig. 1, and the working mechanism of the traditional toggle rod type mechanical press is composed of a crank 11, a connecting rod 12, toggle rods 13 and 14 and a slide block 15. The ordinary motor is adopted to drive the flywheel to run, the kinetic energy released and accumulated by the flywheel and the motor rotate to drive the crank 1 to rotate during working, and the connecting rod 12 and the toggle rods 13 and 14 drive the sliding block 15 to do up-and-down reciprocating motion. Because the movement mode of the working mechanism of the traditional toggle rod press cannot be controlled, the movement mode of the slide block of the traditional toggle rod press is relatively fixed and unchanged, the function of the press is single, the process adaptability is poor, and the motor ceaselessly drives the flywheel to rotate, so that the total energy consumption is high, and the toggle rod press is not suitable for the development of the modern manufacturing industry.
With the development of high power servo motor drives, servo drives have begun to be used in forming equipment. The servo-driven mechanical press is directly driven by a servo motor, and the rotating speed and the torque of a driving motor can be controlled and adjusted in real time, so that the automation and intelligence degree of the press are improved, and the working efficiency is improved; any sliding block characteristic can be obtained, and the process adaptability of the equipment is expanded; and corresponding optimization curves can be adopted according to different processes, so that the working performance is improved. The servo press machine generally cancels a flywheel, simplifies a transmission link, and a driving motor is only started when working, so that the servo press machine has a remarkable energy-saving effect. Meanwhile, the servo press machine has the advantages of being high in precision, environment-friendly and capable of prolonging the service life of the die. Servo presses have therefore been rapidly developed and applied. For the toggle press directly driven by the servo motor, if the working mechanism of the traditional toggle press is still adopted, the instantaneous power and the torque of the selected servo driving motor are far larger than those of the common induction motor of the traditional press, so that the press is expensive in manufacturing cost and high in cost, and is not beneficial to popularization and application. Therefore, a new working mechanism must be employed.
Patent No. CN201510013662.7 discloses "a dual drive toggle link mechanism for a servo mechanical press and a control method thereof". The method provides a double-drive toggle rod mechanism for a servo mechanical press, can realize that the engineering pressure stroke and the bottom dead center of the press are adjustable, the motion mode of a slide block can be set at will, the performance and the applicability of the press are greatly improved, the torque and the instantaneous power of a single drive motor can be reduced, and the motion diagram of a working mechanism is shown in figures 2 and 3. The double-drive toggle rod mechanism for the servo mechanical press comprises a first crank 1, a second crank 1 ', a first connecting rod 2, a second connecting rod 3, a first toggle rod 4, a second toggle rod 5 and a third toggle rod 6, wherein one end of the first crank 1 is connected with a machine body to form a revolute pair O, the other end of the first crank 1 is connected with one end of the first connecting rod 2 to form a revolute pair A, the other end of the first connecting rod 2 is respectively connected with one end of the first toggle rod 4 and one end of the second toggle rod 5 to form a revolute pair C, the other end of the first toggle rod 5 is connected with the machine body to form a revolute pair D, one end of the second crank 1 ' is connected with the machine body to form a revolute pair O ', the other end of the second crank 1 ' is connected with one end of the second connecting rod 3 to form a revolute pair A ', the other end of the second connecting rod 3 is respectively connected with the other end of the first toggle rod 4 and one end of the third toggle rod 6 to form a revolute pair B, the other end of the third toggle rod 6 is connected with a slide block 7 to form a revolute pair E, the slide block 7 is arranged on a guide rail of the machine body to form a moving pair, and the slide block 7 can do reciprocating linear movement along the guide rail of the machine body. Compared with the traditional toggle rod mechanism, the double-drive toggle rod working mechanism for the servo mechanical press is increased from 1 drive to 2 drives, and can obviously reduce the torque and instantaneous power of a single servo drive motor on the premise of keeping the nominal press of the press. The adjustable hydraulic press has the advantages that the adjustable pressure stroke and the adjustable bottom dead center of the press can be realized, the movement mode of the slide block can be set at will, the performance and the applicability of the press are greatly improved, and the torque and the instantaneous power of a single driving motor can be reduced.
The common dual-drive toggle rod working mechanism cannot give full play to the advantages of the working mechanism, can only play a limited role in reducing the torque and instantaneous power of a driving motor and improving the working performance, and is not beneficial to the application of the mechanism in an actual servo press. Therefore, in order to fully exert the advantages of the working mechanism and promote the popularization and application of the working mechanism, a reasonable mechanism optimization design method is provided to optimize the mechanism. However, due to the complex structure, many optimization variables, and multi-objective optimization, the traditional optimization method is difficult to obtain the optimal solution, so that the optimization method of the dual-drive toggle rod mechanism for the servo mechanical press needs to be provided.
Disclosure of Invention
The invention aims to provide an optimization method of a double-drive toggle rod mechanism for a servo mechanical press, aiming at the problems.
The purpose of the invention can be achieved by adopting the following technical scheme:
a method for optimizing a dual drive toggle mechanism includes the following steps:
step 1, determining basic structural parameters of a dual-drive toggle rod working mechanism according to the overall design requirements of a press, and dividing the whole mechanism into an upper toggle rod part and a lower toggle rod part;
step 2, setting structural parameters of the lower elbow rod part according to the maximum total height of the toggle rod mechanism of the press, and assuming that the initial structure of the lower elbow rod part is an isometric toggle rod structure;
step 3, on the basis of the set structural parameters of the lower toggle rod part, taking the upper toggle rod part and the lower toggle rod part as a whole, setting the constraint conditions of the parameters of the upper toggle rod mechanism by taking the driving torque as an optimization target and the parameters of the upper toggle rod mechanism as optimization variables, and performing structural optimization on the dual-drive toggle rod working mechanism to obtain the optimized structural parameters of the upper toggle rod part;
step 4, on the basis of the structural parameters of the upper toggle rod part obtained in the step 3, taking the upper toggle rod part and the lower toggle rod part as a whole, taking the driving torque as an optimization target, taking the parameters of the lower toggle rod mechanism as optimization variables, and setting the constraint conditions of the parameters of the lower toggle rod mechanism, performing mechanism optimization of the dual-drive toggle rod working mechanism to obtain the optimized structural parameters of the lower toggle rod part;
and 5, changing the rod length constraint condition in the step 3, repeatedly performing iterative structure optimization in the step 3 and the step 4, and finally obtaining the optimized structure parameters of the whole mechanism after the driving torque optimized target value tends to be stable and unchanged.
Further, the basic parameters of step 1 include: nominal pressure, nominal pressure stroke, total stroke, maximum total height of the press, maximum total width of the press, and length of each crank, connecting rod, and toggle rod.
Further, in step 2, the two toggle rods of the lower toggle rod part have the same length and are set to be one third of the maximum total height of the mechanism, the two toggle rods are collinear, the length of the connecting rod of the lower toggle rod part is equal to that of the toggle rods, the length of the crank of the lower toggle rod part is one third of that of the connecting rod, the crank and the connecting rod are collinear, and the included angle between the connecting rod and the toggle rods is 90 degrees.
Further, the maximum length of the toggle link of the upper toggle link portion in step 3 is set to be one third of the maximum overall height of the mechanism, the maximum length of the connecting rod of the upper toggle link portion is equal to the maximum length of the toggle link, and the maximum length of the crank of the upper toggle link portion is set to be one third of the maximum length of the toggle link.
Further, the constraint conditions in step 4 are: the maximum rod length of the two toggle links of the lower toggle link part is respectivelyThe maximum rod length of the lower toggle link part connecting rod is l2max=l4maxThe maximum rod length of the crank of the lower toggle link part isObtaining optimized mechanism parameters of the lower toggle link part; wherein,l2max=l4max,Wherein K1、K2The value range of (1) to (1.2) and H is the maximum total height of the mechanism.
Further, the maximum rod length of the upper toggle link part link in step 5 is l5max=H-l4-l6And H is the maximum total height of the mechanism.
Further, after the torque target function value obtained in the step 5 tends to be stable, the judgment condition is thatWherein XiRepresenting the torque objective function obtained at present stepValue, Xi-1And representing all the optimized parameters finally obtained by the torque objective function values obtained in the previous step.
The implementation of the invention has the following beneficial effects:
the invention separately carries out the optimization design of the upper part mechanism and the lower part mechanism. During optimization design, the two driving parts are separately optimized in sequence, namely the two driving parts are independently optimized in a multi-objective mode by taking driving torque and sliding block motion, so that a global extreme value can be effectively found, and the optimization rate is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of an initial position structure of a dual drive toggle operating mechanism of the dual drive toggle mechanism optimization method of the present invention;
FIG. 2 is a schematic structural view of the dual drive toggle mechanism optimization method of the present invention when the crank and the connecting rod are not collinear;
FIG. 3 is a schematic structural diagram of the optimization method of the dual-drive toggle rod mechanism according to the present invention, in which the included angle between the toggle rod and the axis DE is greater than zero;
FIG. 4 is a schematic structural view of an optimized design of the upper toggle link portion of the dual drive toggle link mechanism optimization method of the present invention;
FIG. 5 is a schematic structural view of an optimized design of a lower toggle link portion of the dual drive toggle link mechanism optimization method of the present invention;
FIG. 6 is a block flow diagram of a method for optimizing a dual drive toggle linkage mechanism of the present invention;
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example (b):
referring to fig. 1 to 6, the present embodiment relates to a method for optimizing a dual drive toggle mechanism, comprising the steps of:
step 1, determining basic structural parameters of a dual-drive toggle rod working mechanism according to the overall design requirements of a press, and dividing the whole mechanism into an upper toggle rod part and a lower toggle rod part; the basic structure parameters include: nominal pressure, nominal pressure stroke, total stroke, maximum total height of the press, maximum total width of the press, and length of each crank, connecting rod, and toggle rod.
Step 2, setting structural parameters of the lower elbow rod part according to the maximum total height of the toggle rod mechanism of the press, and assuming that the initial structure of the lower elbow rod part is an isometric toggle rod structure; the length of the two toggle rods of the lower toggle rod part is equal, the length of the two toggle rods is set to be one third of the maximum total height of the mechanism, the two toggle rods are collinear, the length of the connecting rod of the lower toggle rod part is equal to that of the toggle rods, the length of the crank of the lower toggle rod part is one third of that of the connecting rod, the crank is collinear with the connecting rod, and the included angle between the connecting rod and the toggle rods is 90 degrees.
Step 3, on the basis of the set structural parameters of the lower toggle rod part, taking the upper toggle rod part and the lower toggle rod part as a whole, setting the constraint conditions of the parameters of the upper toggle rod mechanism by taking the driving torque as an optimization target and the parameters of the upper toggle rod mechanism as optimization variables, and performing structural optimization on the dual-drive toggle rod working mechanism to obtain the optimized structural parameters of the upper toggle rod part; the maximum length of the toggle link of the upper toggle link part is set to be one third of the maximum total height of the mechanism, the maximum length of the connecting rod of the upper toggle link part is equal to the maximum length of the toggle link, and the maximum length of the crank of the upper toggle link part is set to be one third of the maximum length of the toggle link.
And 4, on the basis of the structural parameters of the upper toggle rod part obtained in the step 3, taking the driving torque as an optimization target by taking the upper toggle rod part and the lower toggle rod part as a whole,taking the lower toggle rod mechanism parameters as optimization variables, and carrying out mechanism optimization of the dual-drive toggle rod working mechanism under the constraint condition of the set lower toggle rod mechanism parameters to obtain optimized structural parameters of a lower toggle rod part; the constraint conditions are as follows: the maximum rod length of the two toggle links of the lower toggle link part is respectivelyThe maximum rod length of the lower toggle link part connecting rod is l2max=l4maxThe maximum rod length of the crank of the lower toggle link part isObtaining optimized mechanism parameters of the lower toggle link part; whereinl2max=l4maxIn which K is1、K2The value range of (1) to (1.2) and H is the maximum total height of the mechanism.
And 5, changing the rod length constraint condition in the step 3, repeatedly performing iterative structure optimization in the step 3 and the step 4, and finally obtaining the optimized structure parameters of the whole mechanism after the driving torque optimized target value tends to be stable and unchanged. The maximum rod length of the upper toggle link part is l5max=H-l4-l6And H is the maximum total height of the mechanism.
After the torque target function value obtained in the step 5 tends to be stable, the judgment condition is thatWherein XiRepresenting the value of the torque objective function, X, obtained in the present stepi-1And representing all the optimized parameters finally obtained by the torque objective function values obtained in the previous step.
Specifically, in the initial position of the dual drive toggle operating mechanism, as shown in fig. 1, when the operating mechanism moves, the crank 1 and the crank 1' both rotate counterclockwise. When the slider 7 is at the bottom dead center of the initial position, the toggle lever 4, the toggle lever 5 and the toggle lever 6 are collinear, i.e., D, C, B and E4 are collinear, and the slider 7 can be moved alongThe DE makes reciprocating motion in the linear direction. When the slide block 7 is positioned at the initial position of the bottom dead center, the crank 1 and the connecting rod 2 are collinear, namely O, A and C3 are collinear, and the included angle between the crank 1 and the x axis isThe crank 1 'and the connecting rod 3 are collinear, namely O', A 'and B3 points are collinear, and the crank 1' forms an angle with the x axisTherefore, when the crank 1 and the crank 1' rotate synchronously, the slide block only passes through the bottom dead center once in a movement period, and the monotonicity of the loading movement of the press machine is ensured.
However, under certain conditions, as shown in fig. 2, when the crank 1 and the connecting rod 2 are not collinear, and the crank 1 'and the connecting rod 3 are not collinear, it can also be ensured that when the crank 1 and the crank 1' rotate synchronously, the slide block only passes through the bottom dead center once in a movement cycle, and the monotonicity of the loading movement of the press machine is ensured. The invention discusses the dual drive toggle operating mechanism in this case.
E.g. total stroke of the mechanism is S0When the slide block slides downwards to be in the nominal pressure stroke, the included angle between the toggle rod 5 and the axis DE in the mechanism is alpha, the included angle between the toggle rod 6 and the axis DE is beta, and as shown in fig. 6, the nominal pressure which can be borne by the mechanism is N. The maximum total height of the press can be defined by a distance H between two points DE in the initial state of the mechanism, and the maximum total height is set to be H0。
As shown in figure 3, the mechanism takes a point D as a coordinate origin, the length of a crank 1 of the upper toggle part mechanism is l1, and the length of a connecting rod 2 is l2The length of the toggle rod 5 is l5The included angle between the crank 1 and the x axis isThe connecting rod 2 forms an included angle with the x axisThe coordinate of the point O is (X)1,Y1) The upper toggle part mechanism is composed of1、l2、l5、Andand (4) completely determining. X1And Y1And l1、l2、l5、Andand (4) correlating. The lower toggle rod part is structurally provided with a crank 1' with the length of l1′The length of the connecting rod 3 is l3The length of the toggle lever 4 is l4The length of the toggle lever 6 is l6The included angle between the crank 1' and the x axis isThe connecting rod 3 forms an included angle with the x axisTo ensure that the upper portion is not constrained too much from the lower portion, the lower toggle portion is assumed to be initially configured in an equal length toggle configuration. Wherein the length of the toggle lever 4 and the toggle lever 6 should be set to one third of the total height of the mechanism, i.e. the length of the toggle lever 4 and the toggle lever 6 should be set to one third of the total height of the mechanismThe length of the connecting rod is equal to that of the toggle rod, the length of the crank 1' is equal to one third of that of the connecting rod, and the angle between the crank, the connecting rod and the X axis is 0 degree.
Since the upper toggle lever part is first optimized, the first step assumes that the structural parameters of the lower toggle lever part are given values. According to the force and motion decoupling optimization design method, when the slide block slides downwards to be in the slide block working stroke and the slide block 7 bears nominal pressure, the driving torque of the crank 1 isThe driving torque of the crank 1' isThe optimization objective is to take the minimum value of N + N', i.e.
According to the initial conditions of the mechanism, the method comprises the following steps:
setting parameters of the maximum total height H of the press machine, wherein H is less than or equal to the set parameters;
for the total stroke S of the pressGeneral assemblyShould be SGeneral assemblySetting parameters more than or equal to;
for theAlways have
When in useWhen the temperature of the water is higher than the set temperature,
when in useWhen the temperature of the water is higher than the set temperature,
because the upper toggle mechanism is a crank-rocker mechanism, there are crank conditions:
l1+l2≤l5+lOD
l1+l5≤l2+lOD
l1+lOD≤l5+l2
wherein l0DRepresenting the gantry, representing point O to pointD linear distance.
According to the manufacturing of the crank connecting rod component and the structural requirement of the machine body, the method comprises the following steps:
l1min≤l1≤l1max
l2min≤l2≤l2max
l5min≤l5≤l5max
X1min≤X1≤X1max
the range of each rod length is limited, the minimum value of the rod length is required by the manufacturing process and the like, and the maximum value of each rod length can be dynamically adjusted along with the optimization calculation process due to the determined value. In which setting is carried out
According to the initial model structure of FIG. 6, the mechanism is composed of1、l2、l5、Andif it is determined completely, the optimized parameter is l1、l2、l5、And
after obtaining the optimized values of the parameters of the upper part of the toggle link mechanism, a basic model as shown in fig. 4 is established, the point D is taken as the origin of coordinates, and the length and the angle of the crank 1, the length and the angle of the connecting rod 2 and the length of the upper toggle link 5 are the optimized values obtained in the previous step. Let the crank 1' have a length of l1The length of the connecting rod 3 is l3The length of the toggle lever 4 is l4The length of the toggle lever 6 is l6The included angle between the crank 1' and the x axis isThe connecting rod 3 forms an included angle with the x axisThe coordinate of the O 'point is (X'1,Y′1) Then the mechanism is composed of1′、l3、l4、l6、Andand (4) completely determining. X'1And Y'1And l1′、l3、l4、l6、Andand (4) correlating.
Taking the optimized parameters of the upper toggle rod part mechanism obtained in the first step as fixed values, and according to a force and motion decoupling optimization design method, when the slide block slides downwards to be in the slide block working stroke and the slide block 7 bears nominal pressure, the driving torque of the crank 1 is at the momentThe driving torque of the crank 1' isThe optimization objective is to take the minimum value of N + N', i.e.
Constraint conditions
According to the initial conditions of the mechanism, the method comprises the following steps:
setting parameters of the maximum total height H of the press machine, wherein H is less than or equal to the set parameters;
for the total stroke S of the pressGeneral assemblyThe sum of s is more than or equal to a set parameter;
when in useWhen the temperature of the water is higher than the set temperature,
when in useWhen the temperature of the water is higher than the set temperature,
because lower part toggle link mechanism is crank rocker mechanism, there is the crank to have the condition:
l1′+l3≤l4+lo′C
l1′+l3≤l4+lo′C
l1′+lo′C≤l4+l3
wherein lo′cRepresenting the gantry, representing the linear distance from point O' to point C;
according to the manufacturing of the crank connecting rod component and the structural requirement of the machine body, the method comprises the following steps:
l1′min≤l1′≤l1′max
l3min≤l3≤l3max
l4min≤l4≤l4max
l6min≤l6≤l6max
X′1min≤X′1≤X′1max
whereinl2max=l4max,Wherein K1、K2The value range of (a) is 1-1.2, which is determined according to a specific optimization process.
According to the initial model structure of FIG. 5, the mechanism is composed of1′、l3、l4、l6、Andif it is determined completely, the optimized parameter is l1′、l3、l4、l6、And
according to the characteristics of the dual-drive toggle rod working mechanism and the optimization principle taking part of the mechanism as a main body, a drive torque iterative optimization algorithm of the dual-drive toggle rod working mechanism is provided, and the specific calculation flow is as follows:
1) according to the overall requirements of the design of the press, the basic technical parameters of the dual-drive toggle rod working mechanism are determined, including nominal pressure, nominal pressure stroke, total stroke, the maximum total height of the press, the maximum total width of the press and the length requirements of each crank, connecting rod and toggle rod.
2) The mechanical parameters of the lower part are set according to the maximum overall height of the press, and the initial structure of the lower toggle rod part is assumed to be an isometric toggle rod structure. Wherein the length of the toggle lever 4 and the toggle lever 6 should be set to one third of the total height of the mechanism, i.e. the length of the toggle lever 4 and the toggle lever 6 should be set to one third of the total height of the mechanismThe length of the connecting rod 3 is equal to the length of the toggle rod, the length of the crank 1' is equal to one third of the length of the connecting rod, and the angle between the crank and the connecting rod and the X axis is 0 degree.
3) On the basis of the set mechanism parameters of the lower toggle link part, the upper toggle link part and the lower toggle linkThe structure of the upper toggle rod part is optimized by taking parameters of the upper toggle rod mechanism as optimization variables and under constraint conditions as a whole of part of mechanisms to obtain optimized mechanism parameters l1、l2、l5、Andin which setting is carried outl2max=l5max,
4) Performing mechanism optimization of the lower toggle part, and performing the mechanism optimization of the lower toggle part under the conditions of optimization variables and constraints of the parameters of the lower toggle mechanism on the basis of the parameters of the upper part mechanism obtained in the step 3), wherein the parameters of the upper toggle part and the lower toggle part are taken as a whole4And l6The maximum rod length condition of (2) should be set to) Obtaining optimized mechanism parameters l1′、l3、l4、l6、Andwhereinl2max=l4max,Wherein K1、K2The value range of (a) is 1-1.2, which is determined according to a specific optimization process.
5) Optimizing the parameters of the lower part mechanism obtained in the step 4) together with the design variables of the upper toggle link mechanism, wherein5The maximum rod length condition of (c) should be set to l5max=H-l4-l6Obtaining optimized mechanism parameters l1、l2、l5、And
6) changing the constraint l of the rod length in step 3)5max=H-l4-l6Repeatedly carrying out the iterative mechanism optimization of the step 3) and the step 4), and judging the condition that the obtained torque target function value tends to be stableWherein XiRepresenting the value of the torque objective function, X, obtained in the present stepi-1Expressing the torque target function value obtained in the last step and finally obtaining an optimized parameter l1、l2、l5、l1,、l3、l4、l6、 And
while the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.