Of robot structure optimize an analysis
- source:GEOFF CNC Machining
A kind of when the after putting forward to be versed in robot of course of study is computer technology appears development of the problem rises new-style and rigid structure, work efficiency and maneuverability are a lot of taller than traditional machinery. Subsequently and those who come is, the structural design of the robot is reducing quality, raise stiffness respect to compare traditional and rigid structure to have higher demand. In designing the job, structural optimization appears more important. In the structure in optimizing a design, finite yuan the law is a more effective method. Normally, the modification that builds model and model is finished by hand. More complex to the structure below the circumstance with the very much place that perhaps needs to revise, optimized time is longer. Calculate among them time is opposite less, build model and structure to revise place to hold proportion bigger. How to reduce the time that builds what model and structure revise, it is the key that raises a structure to optimize efficiency. APDL language is ANSYS software a when provide an user seesaw pattern software that relies on ANSYS program develops an environment. APDL language has the common function of similar and common computer language, if be similar to the parameter definition of invariable definition, variable definition and assignment, branch and loop control a statement, be similar to a subprogram to call grand call wait for a function. Divide this beyond, return a bag to contain stronger mathematical operation capability, like arithmetic manipulation, quite, take rectify and function of the trigonometric function of standard FORTRAN, index, Shuang Quhan is counted etc. Use APDL language to still can read the data in taking ANSYS program database to have mathematical operation, and build analytic model, control the function such as the moving process of ANSYS program. The original design program of the robot structure of paralell connection of a 3 lever. The baseplate of the robot uses door type structure, the length of 3 drive lever is alterable, make extreme can complete designation exercise. Because use 3 drive rod, the core part of crossbeam shows an equilateral triangle on, if pursue,2 are shown. Plane of structural edge pillar cannot design symmetrical form, crossbeam decides hard along the position of X direction between two pillar. And, of original design program finite yuan the analysis makes clear as a result, crossbeam hangs Z of the edge that extend end with what 1 drive lever connects to be out of shape bigger, tigidity comparing and 2, the part that 3 lever connect is a lot of weaker, make an appointment with what for other two lever are in place stiffness very one of. The abhorrent sex of this kind of stiffness gives terminal the athletic precision below expensive work load brings certain influence. Go up certainly the position of direction of crossbeam edge X is very be necessary. To afore-mentioned problems, optimizing strategy commonly is ceaselessly the position of the beam on the change, calculate via trying for many times, find a proper place finally. Try every time calculate, want to revise a model as a result according to computation, build a model afresh. Handle iteration process by hand, if iteration time is more, avoid occurrence error very hard, the probability that optimizes failure is higher. After the model is amended, the wainscot of crossbeam is mixed on muscle board appearance can produce change. Because go up,the shape of in-house knot configuration of crossbeam is compared complex, wainscot is mixed the change of muscle board appearance to going up the influence of crossbeam stiffness is forecasted hard, try the time that calculate more, the workload of modification model also is compared accordingly big. The APDL language that the article uses ANSYS program optimized a problem to give out to afore-mentioned beam position one optimizes strategy. After the analytic model of first time is built, of the user of construction of the instruction that build a model that in using a command to record a file, generates optimize control program, follow-up iteration optimizes the user that the process writes by APDL language to control a program to finish, need artificial interpose no longer. To the graph a shown model undertakes needed time reduces negligible rate modification place, whole the efficiency that optimizes a process has very big rise. 2.
Those who analyse a model build to comprise by 3 parts: Two pillar, a beam and 3 drive lever. Pillar and beam show pillar upside 1 times through the graph muscle of the first level the bolt connection of board place. Be out of shape as a result of what basically consider crossbeam, drive staff share can skip, take the place of in connection place with equivalent force. The core of crossbeam part is 3 place with drive lever connection and the have special purpose opening among, dimension must assure. Other part criterion can as significant as pillar link can. To build modular convenience, the core part make it in beam of ANSYS program lieutenant general a component (Component) . In optimizing a process, appearance of geometry of this one part keeps changeless, change the relative position of it and axis of pillar edge X only, change the geometrical form of connection part only namely. Those who need an attention is, connection part changes geometrical size only in optimizing iteration process, do not change develop to attack structure, can pass a program to be finished automatically. Crossbeam and every pillar passes 6 bolt connection. In bolt connection place, node ought to coupling. In place of blame bolt connection, combinative scale cannot bear pull stress, should set osculatory unit. After osculatory unit is being included in the model, need of the process that seek solution is many nonlinear iteration computation, increase when machine a lot of. The trial balance that has crossbeam and pillar as an organic whole bright, of pillar outside side suffers pull, inside press press. Go up to seeming considering main analysis crossbeam and the connection stiffness that 3 drive lever is in, can skip osculatory unit, outside pillar side builds model of connection face geometry. The connection of crossbeam and pillar is in, have the place of bolt, fluctuation face shares a key to nod, without the place of bolt, fluctuation face has a key to nod severally. The profit that such doing is, reseau analyse time-sharing, in communal key point point generates a node automatically, build the coupling between a pillar and beam to concern. In be not point of communal and crucial point, the node on crossbeam and pillar won't have concern of this kind of coupling. In the inside of pillar, pillar and beam become an organic whole in interface the first line of a couplet on a scroll, all node will be coupling, pillar and beam share these node, is to be in bolt connection place not just. The profit that such doing is, already leave out the contact is unit, can mirror the characteristic of bolt connection again. The connection of pillar bottom and foundation handles rigid total obligation. Main goal of the analysis is the tigidity of crossbeam, can think to go up crossbeam bears in the connection place with 3 drive lever identical load. Can be out of shape according to what computation gets so result, evaluate the stiffness of 3 connection place directly. The structure uses thin wall cast, simulation of Shell63 of board housing unit is used in analysing a model. Of the structure outside wall and muscle board ply is different, the fact that needs to install two groups to differ for board housing unit is invariable (Real Constant) . Same, to build modular convenience, two pillar make it another component. The component that builds pillar core part then and pillar component make it a component (Assembly) . Such, when revising a model, can select the connection part of pillar and beam easily to come out, complete modification process. Through afore-mentioned processing, can build similar analysis model. As a result of the symmetry of model and load, actual computation can take an in part only, total unit number has 8927 only, summary check the number is 4341, use component of triangular reseau analyse entirely. 3.
Optimizing politic to optimize a process is one tries substantially calculate - modification iteration course. With original design plan regards iteration calculative as initiative condition, the requirement that iteration process ends is: The stiffness that connection of 3 drive lever is in is adjacent and equal or iteration frequency is overmuch. To this specific issue, can foretell the crossbeam position when stiffness of 3 connection place is equal is existence, if iteration is not convergent, can be mobile quantity only improper initiative perhaps position is improper. For iteration process can effectively astringent, use what bisect searchs to change the pace grows algorithm, self-correcting shift is measured. Algorithmic a little a few more complex, but not tall to the requirement of initial value, have better versatility. The control technological process that optimizes strategy gives out below. 1. Numerate from inside backup file crossbeam the model data when initiative position; 2. The position of modification beam; 3. Beg the model after solution is revised; 4. Numerate with place of connection of 3 drive lever be out of shape; 5. Whether does judgement satisfy convergent requirement, dissatisfaction is sufficient, after modification shift is measured, return 3, contented, exit a loop; 6. Store be exited after the result that seek solution. The main control code that the program is below reachs the annotate of its function. Build modular instruction specificly to be omited among them, acting with suspension points, to facilitate with control flow contrasts, added the explanatory note with essential part. / the RESUME of mark of batch processing file of BATCH ANSYS, , robbak, db, , 0 from backup file Robbak.
Primitive data is read in in Db / PREP7 enters pre-treatment implement, . . . Delete the connection section of crossbeam and pillar. . . Move crossbeam core component an initiative Step. . . To load carry on one's shoulder and obligation are imposed on geometrical model. . . Reseau differentiates FINISH exits pre-treatment implement / SOLU is entered seek solution implement SOLVE begs solution FINISH to exit seek solution implement / POST1 enters an aftertreatment implement *GET, front, NODE, 2013, u, the node that Z reads connection of lever of the first drive to be in is out of shape to Front*GET, back, NODE, 1441, u, the node that Z reads connection of lever of the 2nd drive to be in is out of shape to Backlastdif=1 last time the mark Step=0 that the absolute value Flag=-1 that Front and Back difference are worth optimizes result feasibility.
05 measure initial value *DO to the shift of best position from initiative position, i, 1, 10, 1 iteration begins circularly, circular variable I, limits extraction a cost 1 ～ 10, the Front in this second computation result mixes pace long 1dif=abs(front-back) the poor absolute value *IF of Back, dif, LE, 1.
0E-6, THEN judges the Dif that need a value to whether satisfy requirement Flag=1, label buy 1*EXIT exits iteration computation *ELSEIF, dif, GE, lastdif, whether does Dif of THEN judgement poor value greaten Flag=2 differs a value to greaten, mark buy 2. . . Bisect law revises Step. . . Continue the position makes starting point before, it is current Step in order to revise the Step after, begin new poor value of *ELSE of computation of round of iteration is not less than expectation value, and taper, need to continue the beam on shift. . . Read in initiative condition data from inside backup file. . . Enter pre-treatment implement AGEN, , p51X, , , , step, , , , the nuclear core of the beam on 1 shift is divided, shift measures Step. . . The connection part of tectonic beam and pillar. . . Impose to load carry on one's shoulder and obligation. . . Reseau differentiates FINISH exits pre-treatment implement / SOLU is entered seek solution implement SOLVE begs solution FINISH to exit seek solution implement / POST1 exits an aftertreatment implement *GET, front, NODE, 2013, u, z gives Front assignment *GET, back, NODE, 1441, u, this file is longer above the terminal of the statement of loop of terminal *ENDDO *DO that Z gives Back assignment Lastdif=dif statement of newer Lastdif*ENDIF If-else, about 1000. Main purpose is to make the structure of the program clear. Having a lot of code is answer use, if a few instructions that build a model and aftertreatment dictate. When using, can make these statements corresponding grand call in the main program, shorten effectively the length of the main program. In addition, the most and material statement building a model in the file is the command from ANSYS program in recording a file, duplicate come over, contain a lot of statements that just use below graphical interface. When be being used with the batch processing means of ANSYS, can delete these commands, also can shorten file length. In afore-mentioned programs, the model appoints place be out of shape is to pass node to read those who take. In reseau analyse cent, succeed to ensure analyse is divided, and do not produce the unit with abominable appearance, used triangular reseau act against one's will. Optimize the each pace iteration of the process, the geometrical appearance of the pillar of the model and part of crossbeam core connection can differ, this meeting makes analyse divides the reseau amount that come out to differ somewhat, the node number that shows emplacement is in differs likely. Basis node number reads extraction data from inside the database is not the data that appoints the position likely. For this, need above all the core part of analyse cent beam, such, the node number on crossbeam is fixed in iteration process every time. Whether is the final result of iteration a feasible result, need to decide through examining parameter Flag. Have Flag=1 only, computation just is feasible as a result, represent iteration course otherwise and did not find optimal place. The mobile quantity memory of crossbeam is in parameter Step. If computation is feasible as a result, the value of Step is crossbeam from original design position the shift to best position is measured. Total iteration number is deposited in parameter I, pass the final cost of I, the feasibility that can estimate analytic result and initiative condition are appropriate. 4.
The analysis optimized a process to have iteration 7 times in all as a result, expend are made an appointment with when machine, found best place. Because the machine reads in the process of the instruction,get more quickly than altering the rate of the model artificially much, the time of modification model is basic negligible. Optimize process place to need time to depend on the time that seek solution. Optimize process photograph to compare with what finish artificially, efficiency had bigger rise, and the factitious error that avoided complex model to appear easily in the process that build a model brings about follow-up iteration computation to give fault or deviate to optimize the problem such as the target. 5.
Verdict analysis makes clear as a result, the article gives out optimizing a method is effective, achieved those who anticipate to optimize a purpose. The advantage of this method is dependability tall, optimize a process to make mistake not easily. It is versatility has been compared next, the design is optimized in similar structure in, the control code that gives out in article need not be made alter greatly can transplant use. Defect is unalterable in optimizing a process the develop that optimizes an object attacks structure. Changing develop to attack below structural condition, the workload of modification model is bigger, can reflect the advantage that gives this method more. Additional, attack to needing to change develop of the structure optimize a problem, the develop that can use ANSYS program to offer attacks optimize a function. If combine the method of the article to it, it is better to can be obtained optimize the effect. CNC Milling CNC Machining