Postprocessor Module Research Articles

A fast task planning system for 6R articulated robots based on inverse kinematics.

Robots bring eventful impacts to the workplace, benefiting from the advantages of implementing any technology should be based on the premise of safety. This work proposes a systematic method to establish a postprocessor module for any specified 6R articulated robot. Instead of obsessively emphasizing achieving the desired locations and orientations by hand guiding grab and dragging a robotic arm for operation in teaching mode, the significant end-effector poses are calculated to form a new path for the joints efficiently in this study. Since robotic motion control is usually a complex system whose users must be well trained and acquainted with using them. There is a need for a GUI solution that can provide intuitive robotic motion control on the current location by the user independently, easy setup, arrangement, adjustment, and monitoring robot motion tasks. The proposed system simplifies the interaction between the technician and the industrial robotic arm in the case of robotic motion control and tracking at a distant location. The presented method is fully adapted to alternate between joint angles and end-effector poses on a graphic user interface system. After developing the capabilities of the solver, a functional postprocessor is programmed inside the proposed GUI system. Examples with specified posture and predefined movements are demonstrated for corroborating the algorithm. The results show considerable efficiency and reliability in task planning and are fully supported for automatic path generation.

The use of a computer modeling system for foundry processes in blank production

The article focuses on the analysis of the results of computer simulation of the technological process of casting the part “Stub”. In the work, the elements of the gating-feeding system were calculated. Based on the calculated data, a digital model was built. An important stage of the work was the digital modeling of the technological process of casting the plug part in the ProCast CAE system. The simulation results were viewed and analyzed in the Visual-Viewer postprocessor module. An analysis of the simulation results made it possible to evaluate the efficiency of the gating system, determine the areas of turbulent flow, the nature of filling the zone with a high flow rate, possible places of mold erosion, places of formation of air pockets that can affect the occurrence of gas inclusions in the casting. The nature of the distribution of the temperature gradient in the casting, the time and uniformity of the solidification of the casting were also studied.

Структура и особенности программного комплекса для геофизических геометрических 3D-инверсий

The structure and features of a software package for 3D inversion of geophysical data are considered. The presented software package is focused on solving direct and inverse problems of electrical exploration and engineering geophysics. In addition to the parameters that determine physical properties of the medium, the software package allows you to restore the geometry parameters of the geophysical model, namely layer reliefs and boundaries of three-dimensional inclusions. The inclusions can be in the form of arbitrary hexagons or prisms with a polygonal base. The software package consists of four main subsystems: an interface, subsystems for solving direct and inverse problems, and a client-server part for performing calculations on remote computing nodes. The graphical interface consists of geophysicist-oriented pre- and postprocessor modules that allow you to describe the problem and present the results of its solution in user-friendly terms. To solve direct problems, the finite element method and the technology for dividing the field into normal and anomalous components are used. At the same time, special methods of discretization of the computational domain are used, which make it possible to take into account both the complex three-dimensional structure of the environment and the presence of man-made objects (wells) in the computational domain. To increase the efficiency of solving direct problems, nonconforming grids with cells in the form of arbitrary hexahedrons are used. Methods for efficient calculation of derivatives (with respect to these parameters) necessary for solving inverse problems by the Gauss-Newton method are also described for the geometry parameters. The main idea for efficient derivatives computation is to identify the effect of changing the value of the parameter (used to compute the value of the generalized derivative) on the problem. The main actions performed by the subsystem for solving inverse problems and the features associated with the processing of geometry parameters are described.

NX CAM post processing errors: Machine data file generator vs. post builder

Replacing or upgrading software packages requires a detailed analysis and testing. This is especially important for software modules that are part of the production process. Machining of free-form surfaces always requires using of a five-axis milling machine. Tool path post-processing for these machines always attracts special attention. The most important part of the postprocessor is implemented IKS (Inverse Kinematic Solver). Implemented IKS in the postprocessor must accurately describe the kinematics of milling machine in the production plant. Military Technical Institute performed parallel testing of two postprocessing modules of CAD/CAM system Siemens PLM NX: and old GPM (Graphics Postprocessor Module and a new module MOM (Manufacturing Output Manager). Complete analysis was sent to the NX support center and application engineers confirmed that the old and new postprocessors do not behave identically. The paper describes in detail the analysis and explains the solution of the presented problem.

Developing postprocessor for five-axes milling machines with dual rotary head

Five axis milling technology has been in use nearly 25 years in VTI Belgrade. Primarily it is used in the production process of wind tunnel models. For generating tool path and the post-processing paths, used postprocessor generated on Siemens PLM NX. Producer of CAD/CAM software, in newer versions, the old concept of post processing GPM (Graphics Postprocessor Module) replaced it with a new, improved, module MOM (Manufacturing Output Manager). The VTI are identified in the CNC code for five axes milling, generated using the MOM module, some errors. Product support application engineer confirmed all the allegations VTI. This was the reason for the development of its own postprocessor for five axes milling machines with double rotating head. The paper gives a detailed overview of the development based on the kinematic model of the five-axes milling machine in VTI Belgrade.

HEARING AID AND METHOD FOR OPERATING A HEARING AID

The invention relates to a method for a hearing aid wearer to actively operate a hearing aid. A signal processing section of the hearing aid has a demixing module for separating audio signals and a postprocessor module which sets up a hold mode of operation for the hearing aid. An audio signal, which is preferred by the hearing aid wearer, from an ambient sound, is tracked and selected by virtue of the hearing aid wearer transmitting to the hearing aid a command which sets up the hold mode of operation in the signal processing section of the hearing aid for a certain period. The signal processing section tracks the preferred audio signal and selectively takes account of it in an output sound from the hearing aid such that it is audibly highlighted for the hearing aid wearer in comparison with another audio signal and is thereby perceived better.

A Five-Axis CNC Machine Postprocessor Based on Inverse Kinematics Transformation

This paper presents a postprocessor for five-axis milling machine that capable of converting CL (cutter location) data to machine control data (NC program). The proposed postprocessor method is based on inverse kinematics transformation and postprocessor module is programmed in Visual Basic language. The Deckel Maho DMU 50 eVoluion five-axis machine with two rotary axes (B and C) on the table is modeled and verified in software VERICUT® to validate the NC data generated by proposed postprocessor.

Tool Path Planning and NC Generation of Tilted Plane Machining Features for Five-Axis Machining

Designs of free-form surface products are becoming increasingly complex. In traditional three-axis machine tool machining, errors that are caused by repetitive positioning and the costs of fixture jig design and manufacturing are critical. Since multi-axis machining provides two more rotational degrees of freedom than a three-axis machine tool, the former can solve these problems, and has therefore become the trend of precision cutting. As multi-axis machined parts often have holes and grooves on the tilted plane, this work proposes a method for machining tilted working plane features and for NC generation on a five-axis machine. The developed module can provide common geometric features, allowing the user to alter the machining feature and sequence on the tilted plane quickly using the parent-child relationship in a tree diagram, and plan the tool path. The postprocessor module developed in this paper can transform the tool path into an NC program required for machining. Finally, solid cutting simulation software is utilized to confirm the feasibility and correctness of the tool path and NC data of the tilted plane machining feature.

Study on the Temperature Changing Rules of U75 V Rail in the Cooling Process

Caused by the differences in volume and heat dissipation area of rail head and bottom, latent heat of phase transition releasing and other reasons, the complicated temperature changes occurs in rail head and bottom between during the cooling process, especially in solid state phase transition. In the paper, the ANSYS heat-stress couple module is adopted to carry on numerical simulation on the cooling process of 60kg/m U75V heavy rail. Though the post-processing result analyzed by using the post-processor module, we got the temperature changing rules for heavy rail cooling process. This paper is of great reference value for the bending deformation study in the hundred-meter heavy rail cooling processing.

An Integrated CAD/CAM System for Manufacturing Lead Frame for Semiconductors

This paper describes the development of the computer-aided design of a lead frame, for a semiconductor, with a precise piercing operation for progressive working. The approach is based on knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. An attempt is made to link programs incorporating a number of expert design rules together to form a useful package for process planning and die design. This system is composed of six modules, which are input and shape treatment, production feasibility check, strip-layout, die-layout, modelling, and post-processor modules. Based on knowledge-based rules, it considers several factors such as material and thickness of the product, complexities of blank geometry, punch profiles, diameter and material of a wire, and the availability of a press. As the forming process and the die design system, using 2D geometry recognition for a high-precision product, are integrated with the technology of process planning, die design, and CAE analysis, the standardisation of die parts for a lead frame for a semiconductor with a high-precision piercing process is possible. Strip-layout and die-layout drawings, generated in strip-layout and die-layout modules, are displayed in a graphic form. In order to carry out the automation of the working parts of the die, NC data are generated in a post-processor module using a modelling module according to the die-layout drawings. Results obtained, using the modules, enable the design and manufacture of a lead frame for a semiconductor to be more efficiently performed.

Improvement of the Accuracy in Cornering Cut Using End Mill

The Surface, generated by end milling operation, is deteriorated by tool runout, vibration, friction, tool deflection, etc. Especially in cornering cut, surface accuracy is usually determined by varying cutting forces, which causes tool deflections. Cutting conditions like feed rate is usually kept constant during machining a part, which causes dimensional error in severe cutting. Cornering cut is a typical example of deterioration of surface accuracy when constant feed rate is applied. Therefore it becomes important to develop NC post processor module to determine optimal cutting conditions in various cutting situations. In this paper, cutting force is predicted in cornering cut with flat end mill and feed rate is determined by constraining constantly resultant force. Also some control characteristics of CNC machining center are evaluated.

An Automated Progressive Process Planning and Die Design and Working System for Blanking or Piercing and Bending of a Sheet Metal Product

This paper describes the development of a computer-aided design and manufacturing system for irregular-shaped sheet metal products for blanking or piercing and bending operations. The approach is based on knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. This program for the system has been written in AutoLISP using AutoCAD and on SmartCAM using a personal computer and is composed of nine modules, which are input as shape treatment, flat pattern-layout, production feasibility check, blank-layout, strip-layout, die-layout, data-conversion, modelling, and post-processor modules. Based on knowledge-based rules, the system is designed by considering several factors, such as material and thickness of product, complexities of blank geometry and punch profile, diameter and material of a wire, and the availability of a press. This system is capable of unfolding formed sheet metal to give a flat pattern and automatically accounts for the adjustment of bending allowances to match tooling requirements by checking dimensions and generating NC data automatically according to the drawings of the die-layout module. Results obtained using the modules enable the designer and manufacturer of blanking or piercing and bending dies to be more efficient in this field.

Numerical simulation of leaflet flexure in bioprosthetic valves mounted on rigid and expansile stents

Recent studies suggest that flexural stresses induced during the opening phase may be responsible for much of the mechanical failures of bioprosthetic heart valves. Sharp leaflet bending is promoted by the mounting of valves on rigid stents that do not mimic the systolic expansion of the natural aortic root. We, therefore, hypothesized that flexural stresses could be significantly reduced by incorporating a flexible or expansile supporting stent into the valve design. Using our own non-linear finite element code (INDAP) and the pre- and post-processor modules of a commercial finite element package (PATRAN), we simulated the opening and closing behaviour a trileaflet bovine pericardial valve. The leaflets of this valve were assumed to be of uniform thickness, with a non-linear elastic behaviour adapted from experimentally obtained bending stiffness data. Our simulations have shown that during maximal systolic valve opening, sharp curvatures are induced in the leaflets near their commissural attachment to the supporting stent. These areas of sharp flexure experience compressive stresses of similar magnitude to the tensile stresses induced in the leaflets during valve closure. By incorporating a stent with posts that pivot about their base, such that a 10% expansion at the commissures is realized, we were able to reduce the compressive commissural stressing from 250 to 150 kPa. This was a reduction of 40%. Conversely, a simple pliable stent with stent posts that deflect inward and outward under load did not achieve a significant reduction of compressive stresses. This numerical analysis, therefore, supports the theory that (i) high flexural and compressive stresses exist at sites of sharp leaflet bending and may promote bioprosthetic valve failure, and (ii) that proper design of the supporting stent can significantly reduce such flexural stresses.

The boundary element method in engineering practice

The great interest that numerical methods and in particular finite dements, attracted in the engineering community since the beginning of the 1960s has had two important consequences. Firstly, it stimulated an impressive amount of work in computational techniques and efficient engineering software. Secondly, it originated a substantial volume of research into the basic physical principles, such as variational techniques, mixed methods and weighted residuals approximations. All this was useful to consolidate the finite element method and to enable it to solve a wide variety of engineering problems. Engineers were quick to appreciate the advantages of finite elements and the method developed rapidly. The main difficulty from the practicing engineer's point of view has been the necessity of providing complex geometrical definitions especially when working with threedimensional problems. The wealth of information required to run a code and the resulting output has made finite element systems cumbersome to use and the results more difficult to interpret. An attempt to overcome this problem has been the development of preand post-processor modules but they require even more complex computer facilities. At the beginning of the 1970s, because of the above mentioned difficulties, small groups of researchers started to search for a different theoretical solution to the problem. The basic idea was to develop analysis techniques that were better suited to solve l a r g e mainly three-dimensionalproblems. Some of them preferred reduction techniques many of which can be traced to pre-computer times. Other researchers investigated the use of mixed principles as a way of obtaining more accurate results than when using displacement or potential finite element formulation. An excellent exposition of these methods in structural mechanics can be found in the book by WashizuJ These developments run in parallel with new advances in application of boundary integral equation techniques which were until recently considered as a different type of analytical method, somewhat unrelated to approximate techniques. They became popular in Western Europe through the work of a series of Russian authors, such as Muskhelishvili, ~ Mikhlin, 3 Kupradze 4 and Smirnov s but were not very popular with engineers. A predecessor of some of this work was Kellog 6 who applied integral equations for the solution of Laplace's type problems. Integral equation techniques were popular for certain fluid mechanics and potential problems and known as the source method, which is now classified as an 'indirect' method of analysis, i.e. the unknowns are not the physical variables of the problem. Work on this method was carried out in the

WEMAP: A general purpose system for electromagnetic analysis and design

WEMAP (Westinghouse Electric and Magnetic Analysis Program) is a general purpose system for electromagnetic analysis. It is being developed at the Westinghouse Electric Corp. and is currently running on a Prime 450 at the R&D center. The purpose of WEMAP is to provide design engineers with a simple set of tools to evaluate their electromagnetic designs. This paper describes the system and its preprocessor, executive, analysis and postprocessor modules. A nonlinear magnetostatic problem is shown as an example.