CN106802979B - Finite element analysis based welding robot model simplification method - Google Patents
Finite element analysis based welding robot model simplification method Download PDFInfo
- Publication number
- CN106802979B CN106802979B CN201611218659.XA CN201611218659A CN106802979B CN 106802979 B CN106802979 B CN 106802979B CN 201611218659 A CN201611218659 A CN 201611218659A CN 106802979 B CN106802979 B CN 106802979B
- Authority
- CN
- China
- Prior art keywords
- robot
- bearing
- servo motor
- welding robot
- speed reducer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/23—Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/06—Power analysis or power optimisation
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Geometry (AREA)
- General Physics & Mathematics (AREA)
- Evolutionary Computation (AREA)
- General Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Manipulator (AREA)
Abstract
The invention discloses a method for simplifying a welding robot model based on finite element analysis, which comprises the steps of simplifying a speed reducer, a servo motor, a base and a bearing and simplifying the shape of the speed reducer into a cylinder. The invention simplifies the robot system model, the mesh is easy to be divided, the divided mesh has high quality, the number of the meshes is reduced, and the calculation time is shortened, so that the robot system model is easy to be applied to a common calculation platform for calculation. The divided models are solved and compared with the actual measurement result, the result shows that the calculation result is reliable, and the model simplification method is proved to be effective.
Description
Technical Field
The invention relates to computer aided design, in particular to a method for simplifying a welding robot model based on finite element analysis.
Background
When the structure modification of the industrial robot structure design considering dynamic factors is carried out, experience is combined with repeated actual measurement as a main means, the method greatly slows down the design speed, increases the design cost, and the design quality is difficult to achieve the optimum. The existing solution is to predict the structural characteristics of the whole robot in the robot design stage by means of CAE software, is beneficial to judging the quality of the robot structural scheme and realizing the dynamic design of the structure, and has very important significance for improving the success rate of one-time design of the industrial robot.
The basic idea of using the finite element method is to discretize the continuous solution area of the problem into a group of finite number of units which are connected together in a certain way, i.e. a unit subdivision. Since the units can be combined in different coupling modes and the units themselves can have different shapes, the solution domain with complicated geometric shapes can be modeled. Generally, the finer the model mesh is, the higher the calculation accuracy, but the longer the calculation time is, the higher the requirement on the calculation platform is. Studies have shown that the computational accuracy is not greatly improved when meshing to a certain size, but rather the computational time required is exponentially increased. The six-axis welding robot is complex in structure, and when mechanical analysis is carried out, particularly when dynamic analysis is carried out, a dynamic model of the six-axis welding robot often has the characteristics of complex multiple degrees of freedom, high nonlinearity and high coupling, if the number of grids is large and the quality of the grids is poor, a common computing platform cannot carry out computing or even convergence occurs due to the quality of the grids in the computing process, so that computing failure is caused.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the defects in the prior art, the invention aims to provide a method for simplifying a welding robot model based on finite element analysis, which models the welding robot by using the idea of finite elements, improves the quality of grids and reduces the number of the grids by simplifying a robot system model, so that the method is easy to be applied to a common computing platform for computing.
The technical scheme is as follows: a simplification method of a welding robot model based on finite element analysis comprises the following steps:
(A) simplifying the shape of a speed reducer of the welding robot into a cylinder;
(B) measuring physical parameters of the speed reducer through experiments, wherein the physical parameters comprise rigidity and mass;
(C) imparting to the simplified cylinder a material that meets the physical parameters determined in step (B);
(D) calculating the elastic modulus E and the shear modulus G of the material according to the rigidity of the speed reducer in the step (B);
(E) calculating the Poisson's ratio according to the elastic modulus E and the shear modulus G in the step (D).
Further, the diameter of the cylinder in the step (A) is consistent with the diameter of the mounting surface with a smaller area in the speed reducer.
Further, the height of the cylinder in the step (A) is the distance between two mounting surfaces of the speed reducer.
Further, the servo motor simplification of the welding robot comprises the following steps:
(a) setting a simulation pose of the robot in simulation software;
(b) extracting barycentric coordinates of the servo motors on all the axes of the robot under the pose set in the step (a);
(c) simplifying the servo motor at the gravity center coordinate position of the servo motor into a mass point unit, and endowing the mass of the servo motor to the mass point unit;
(d) connecting the mass point unit with a bearing structure of the servo motor, and averagely distributing the mass of the servo motor to the bearing structure;
(e) changing the simulation pose of the robot and repeating the steps (a) - (d) until the barycenter of the robot in all poses needing simulation is extracted;
further, the bearing structure in the step (d) is a bolt hole on the bottom surface of the robot base; a rod unit is provided between the top and bottom of the bolt hole to connect the top and bottom surfaces.
Further, the base simplification of the welding robot includes: removing process details on the base, reserving bolt holes for bearing on the bottom surface of the base and dividing grids.
Further, the size of the mesh at the bolt hole is set to be 2-3mm when the mesh is divided.
Further, removing process details from the base specifically includes restoring chamfers and radii to right angles, eliminating non-bearing mesas, and process holes.
Further, the bearing simplification of the welding robot includes: removing bearings which do not affect the rigidity and the bearing capacity of the robot; the bearing which influences the rigidity and the bearing capacity of the robot is simplified into a mass spring unit, and the mass of the bearing is evenly distributed to two ends of the mass spring unit.
Has the advantages that: the invention simplifies the robot system model, the mesh is easy to be divided, the divided mesh has high quality, the number of the meshes is reduced, and the calculation time is shortened, so that the robot system model is easy to be applied to a common calculation platform for calculation. The divided models are solved and compared with the actual measurement result, the result shows that the calculation result is reliable, and the model simplification method is proved to be effective.
Drawings
FIG. 1 is a schematic structural diagram of a welding robot body;
FIG. 2(a) is a schematic diagram of a reducer structure;
FIG. 2(b) is a simplified model diagram of the reducer of the present invention;
FIG. 3 is a schematic diagram of a servo motor;
FIG. 4(a) is a schematic view of a robot base structure;
FIG. 4(b) is a simplified model schematic of the robot base of the present invention;
FIG. 5 is a schematic view of a bearing construction;
FIG. 6 is a schematic diagram of natural frequency measurement using simple harmonic excitation;
fig. 7 is a schematic diagram of displacement measurement using a laser method.
Detailed Description
The technical solution is described in detail below with reference to a preferred embodiment and the accompanying drawings.
A simplified method based on finite element analysis welding robot model is characterized in that the welding robot body structure is shown in figure 1, the welding robot system body mainly comprises a base 1, a shoulder casting 2, a large arm 3, an elbow casting 4, a small arm 5, a wrist joint 6 and the like, and in addition, six servo motors 7, a speed reducer, a gear pair contained in a transmission chain and the like. The six-degree-of-freedom robot body is used for providing a smart mechanical structure, executing set path planning and speed planning, the servo motor 7 converts a voltage signal into a torque and a rotating speed to drive a control object, and the speed reducer reduces the rotating speed to obtain a large torque.
The simplification of the welding robot mainly comprises the simplification of a speed reducer, a servo motor 7, a base 1 and a bearing, the simplification of each component is relatively independent, one component can be selected by adopting the method for simplification, and other components which are not described can be provided with a simulation model according to the conventional technical means in the field.
As shown in fig. 2(a), the reducer of the welding robot has a function of reducing the rotational speed to obtain a large torque, and has a complicated structure including gears, bearings, and other structures inside. The speed reducer is located at the joint between each part of the robot, if the speed reducer model is simplified unreasonably, the joint becomes a weak link, and when mechanical analysis is carried out, the natural frequency of the body is reduced, so that the deviation of the calculation result is too large.
As shown in fig. 2(b), the reduction gear is simplified, and the method comprises the following steps:
(A) simplifying the shape of a speed reducer of the welding robot into a cylinder; the speed reducer is connected with other components through bolts, the plane where the speed reducer is combined with the components through the bolts is an installation surface and generally comprises two installation surfaces, the areas of the two installation surfaces are unequal, the diameter of the cylinder is consistent with the diameter of the installation surface with the smaller area in the speed reducer, namely the diameter of the rightmost side surface (B surface) of the speed reducer in the drawing, the height of the cylinder is the distance between the two installation surfaces of the speed reducer, namely the vertical distance between the surface A and the surface B in the drawing, the cylinder is convenient to install after simplification, and the connection between the surface A and the combination surface is directly arranged in simulation software.
(B) Measuring physical parameters of the speed reducer through experiments, wherein the physical parameters comprise rigidity and mass, and the rigidity comprises torsional rigidity and bending rigidity;
(C) imparting to the simplified cylinder a material that meets the physical parameters determined in step (B);
(D) calculating the elastic modulus E and the shear modulus G of the material according to the rigidity of the speed reducer in the step (B):
wherein: k bending is the bending stiffness of the speed reducer; k torsion is the reducer torsional stiffness; ip is the polar moment of inertia of the cylinder;
(E) and (D) calculating the Poisson ratio v according to the elastic modulus E and the shear modulus G in the step (D).
The servo motor 7 of the welding robot is shown in fig. 3, the servo motor 7 is a driving system in a robot system, the number is large, the quality is large, unreasonable simplification can lead to uneven stress of a bearing position, and the gravity center of a robot body can be deviated.
The servo motor 7 of the welding robot is simplified and comprises the following steps:
(a) setting a simulation pose of the robot in simulation software;
(b) extracting barycentric coordinates of the servo motor 7 on each axis of the robot under the pose set in the step (a);
(c) simplifying the servo motor 7 into a mass point unit at the gravity center coordinate of the servo motor, and endowing the mass of the servo motor 7 to the mass point unit;
(d) connecting the mass point units with a bearing structure of the servo motor 7, and distributing the mass of the servo motor 7 on the bearing structure evenly; the load bearing structure in this embodiment is a bolt hole on the bottom surface of the robot base 1, and a rod unit is provided between the top and bottom of the bolt hole to connect the top and bottom surfaces.
(e) Changing the simulation pose of the robot and repeating the steps (a) - (d) until the barycenter of the robot in all poses needing simulation is extracted;
the base 1 of the welding robot is shown in fig. 4(a), and the base 1 of the welding robot is simplified as shown in fig. 4(b), and includes: removing process details which have little influence on the rigidity performance and the bearing capacity of the robot on the base 1, reserving bolt holes for bearing on the bottom surface of the base 1, dividing grids, and setting the size of the grids at the bolt holes to be 2-3mm when dividing the grids. Since the bolt holes on the bottom surface of the base 1 play a main bearing role, the bolt holes for bearing on the bottom surface are all reserved, and the size of the grid at the bolt holes is set to be smaller when the grid is divided. The process details of removing the base 1 specifically include restoring the chamfer and the radius to a right angle, removing non-bearing table surfaces (i.e., small table and turning surfaces), and process holes.
Bearing of welding robot as shown in fig. 5, the bearing simplification of the welding robot includes: removing bearings which do not affect the rigidity and the bearing capacity of the robot; simplifying a bearing influencing the rigidity and the bearing capacity of the robot into a mass point spring unit, and equally distributing the mass of the bearing to two ends of the mass point spring unit; the whole system is assembled by various components, the combination part is a combination part, the combination belongs to flexible combination, the rigidity of the system is reduced, the damping is increased, and the natural frequency of the system is reduced. When the bearing is at the joint part, the natural frequency of the system is influenced, namely the bearing influences the rigidity and the bearing capacity of the robot; the stiffness of the bearing can be calculated by the following equation.
Wherein: kr is the bearing stiffness; ff is the radial load; z is the number of rolling elements; l is the effective contact length of the rolling bodies in the bearing; α is the bearing contact angle.
Fig. 6 shows a schematic diagram of the robot natural frequency test by the simple harmonic force resonance method. The robot is excited by simple harmonic force, so that the resonance of the robot can be caused, the natural frequency of each order of the robot system is found by using the sensor, and the obtained natural frequency is compared with the frequency obtained by simplified simulation according to the embodiment.
Fig. 7 shows the displacement of the test robot under heavy load conditions using a laser method. The pose of the robot is adjusted, then three laser probes are aligned to the test bench according to the standard, the sensors corresponding to the probes are set to be zero, then heavy load is hung on the robot, the base can shift, the probes can capture the change, and therefore the change of the numerical value of the sensors can be caused. And the values on the sensors are the displacements of the robot in the position and the load condition in the direction of X, Y, Z respectively, the displacements of the heavy-load robot hung in different positions and postures are measured by the method respectively, and the measured displacements are compared with the displacement results of the robot obtained by simulation software to verify the effectiveness of model optimization.
The above is only a preferred embodiment of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (2)
1. A simplification method for a welding robot model based on finite element analysis is characterized in that the speed reducer simplification of the welding robot comprises the following steps:
(A) simplifying the shape of a speed reducer of the welding robot into a cylinder, wherein the diameter of the cylinder is consistent with the diameter of one mounting surface with a smaller area in the speed reducer, and the height of the cylinder is the distance between the two mounting surfaces of the speed reducer;
(B) measuring physical parameters of the speed reducer through experiments, wherein the physical parameters comprise rigidity and mass;
(C) imparting to the simplified cylinder a material that meets the physical parameters determined in step (B);
(D) calculating the elastic modulus E and the shear modulus G of the material according to the rigidity of the speed reducer in the step (B);
(E) calculating a poisson's ratio according to the elastic modulus E and the shear modulus G in step (D);
the servo motor (7) of the welding robot is simplified and comprises the following steps:
(a) setting a simulation pose of the robot in simulation software;
(b) extracting barycentric coordinates of the servo motor (7) on each axis of the robot under the pose set in the step (a);
(c) simplifying the servo motor (7) into a mass point unit at the gravity center coordinate of the servo motor, and endowing the mass of the servo motor (7) to the mass point unit;
(d) connecting the mass point units with a bearing structure of a servo motor (7), and evenly distributing the mass of the servo motor (7) to the bearing structure, wherein the bearing structure is a bolt hole on the bottom surface of the robot base (1); a rod unit is arranged between the top and the bottom of the bolt hole to connect the top surface and the bottom surface;
(e) changing the simulation pose of the robot and repeating the steps (a) - (d) until the barycenter of the robot in all poses needing simulation is extracted;
the bearing simplification of the welding robot includes: removing bearings which do not affect the rigidity and the bearing capacity of the robot; simplifying a bearing influencing the rigidity and the bearing capacity of the robot into a mass point spring unit, and equally distributing the mass of the bearing to two ends of the mass point spring unit;
the base (1) of the welding robot is simplified and comprises: removing process details on the base (1), reserving bolt holes for bearing on the bottom surface of the base (1) and dividing grids; the process details of removing the base (1) comprise restoring the chamfer and the rounding to a right angle, deleting the non-bearing table top and the process hole.
2. The simplified method for finite element analysis based welding robot model according to claim 1, wherein the mesh size at bolt hole is set to 2-3mm when dividing the mesh.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611218659.XA CN106802979B (en) | 2016-12-26 | 2016-12-26 | Finite element analysis based welding robot model simplification method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611218659.XA CN106802979B (en) | 2016-12-26 | 2016-12-26 | Finite element analysis based welding robot model simplification method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106802979A CN106802979A (en) | 2017-06-06 |
| CN106802979B true CN106802979B (en) | 2020-09-22 |
Family
ID=58984152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201611218659.XA Active CN106802979B (en) | 2016-12-26 | 2016-12-26 | Finite element analysis based welding robot model simplification method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106802979B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112487564B (en) * | 2019-09-10 | 2023-11-21 | 北京精雕科技集团有限公司 | Optimal design method of turntable bottom plate |
| CN110795876B (en) * | 2019-10-23 | 2023-06-23 | 珠海格力智能装备有限公司 | Method for establishing finite element equivalent model of speed reducer |
| CN110837708B (en) * | 2019-11-05 | 2023-10-27 | 珠海格力智能装备有限公司 | Simulation checking method of robot, storage medium and processor |
| CN112800557A (en) * | 2021-01-30 | 2021-05-14 | 埃夫特智能装备股份有限公司 | Topological optimization method for transition plate of speed reducer of industrial robot |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6544012B1 (en) * | 2000-07-18 | 2003-04-08 | George H. Blume | High pressure plunger pump housing and packing |
| CN101704247B (en) * | 2009-11-12 | 2011-02-02 | 河南工业大学 | Amphibious bionic variable magnetism sucker |
| US9339169B2 (en) * | 2011-12-03 | 2016-05-17 | The Regents of University of Colorado, a body Corporate | Robotic capsule endoscope for minimally invasive surgical procedures, micro-patterned treads for friction enhancement of a robotic capsule endoscope in a biological environment, and process for fabrication of micro-treads |
| CN103810307A (en) * | 2012-11-08 | 2014-05-21 | 史树元 | CAD (computer aided design)-based complicated mechanical design method |
| CN104484511A (en) * | 2014-12-02 | 2015-04-01 | 深圳控石智能***有限公司 | Simulation analysis based dynamic characteristic design method for robot structures |
| CN105184031B (en) * | 2015-11-04 | 2018-05-22 | 上海无线电设备研究所 | A kind of light-weight design method for the people's handle configurations that put together machines |
| CN105269049B (en) * | 2015-11-28 | 2017-07-14 | 沈阳飞机工业（集团）有限公司 | A kind of aircraft skin is without surplus digital control milling method |
| CN106202666B (en) * | 2016-07-01 | 2019-03-05 | 大连理工大学 | A kind of calculation method of marine shafting bearing adjustment of displacement |
-
2016
- 2016-12-26 CN CN201611218659.XA patent/CN106802979B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN106802979A (en) | 2017-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106802979B (en) | Finite element analysis based welding robot model simplification method | |
| Abe | Trajectory planning for residual vibration suppression of a two-link rigid-flexible manipulator considering large deformation | |
| Erkaya | Prediction of vibration characteristics of a planar mechanism having imperfect joints using neural network | |
| CN110539302B (en) | Industrial robot overall dynamics modeling and dynamics parameter identification method | |
| CN110427719B (en) | Dynamic stiffness modeling method for flexible support gear transmission device | |
| Khadem et al. | Analytical development of dynamic equations of motion for a three-dimensional flexible link manipulator with revolute and prismatic joints | |
| CN109746901B (en) | Dynamic load information calculation method for exoskeleton robot | |
| CN109634111A (en) | A kind of high-speed overload Robotic Dynamic Method for Calculating Deformation | |
| CN109255141B (en) | Optimization method for cross section shape of forward conceptual design of automobile body | |
| CN114611362B (en) | Installation and debugging method for working face of large instrument, electronic device and medium | |
| CN106154838A (en) | The residual oscillation suppressing method of a kind of positioner and system | |
| Xu et al. | Dynamic and motion consistency analysis for a planar parallel mechanism with revolute dry clearance joints | |
| Zhang et al. | Modal and natural frequency sensitivity analysis of electrohydraulic Stewart platform | |
| Pan et al. | Dynamics modeling of spraying robot using Lagrangian method with co-simulation analysis | |
| Jeřábek et al. | Increase of the effective production of crankshafts for ship engines | |
| CN103217924A (en) | Dynamics modeling method of over-constrained heavy parallel machine tool applied to real-time control | |
| CN104820728A (en) | Dynamics modeling method for paddy field laser grader levelling system | |
| Swiatek et al. | Dynamic simulation and configuration dependant modal identification of a portable flexible-link and flexible-joint robot | |
| CN107169200A (en) | A kind of computational methods for determining cylindrical boundary rigidity | |
| Luo et al. | Rigid-flexible coupling dynamics analysis of a spot-welding robot | |
| Kivila | Modeling, estimation and control for serial flexible robot arms | |
| Zhang et al. | A novel dynamic method to improve first-order natural frequency for test device | |
| CN111783258A (en) | Estimation method for inherent characteristics and pitch diameter vibration of thin rim gear system | |
| Liu et al. | Rigid-Flexible Coupling Simulation and Vibration Analysis of Flexible Robot | |
| Langen et al. | Simulation of dynamic behaviour of a FPSO crane |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |