NI Motion Assistant Taking CAD Profiles To Motion In Minutes

Publish Date: Aug 24, 2016 | 6 Ratings | 3.67 out of 5 | Print

Overview

A wide set of applications ranging from engraving or cutting sheet metal, glass, wood, foam and cloth to scanning applications in the semiconductor, life sciences and electronics industries require following a precise motion profile. CAD (Computer-Aided Design) and drafting packages offer all the right tools for creating accurate profiles and are commonly used for this purpose. In the past, connecting these profiles to real hardware has been a time consuming and manual process. This whitepaper describes how new tools from National Instruments are simplifying, adding flexibility and allowing machine builders to make faster moves.

Table of Contents

  1. Introduction
  2. Architecture Overview
  3. CAD File
  4. Motion Assistant
  5. XML
  6. Programming Language
  7. Motion Controller 
  8. Conclusion

1. Introduction

For a machine builder implementing a precise motion profile in hardware involves spending several hours translating a CAD drawing into a set of contour points that the motion hardware control tools can understand and follow. Once the points are translated additional time needs to be spent testing the points for inaccuracies. This process is not very flexible since changing or adding news moves can mean repeating these time intensive steps. The ability to directly go from a CAD drawing to implementing the profile in hardware can significantly reduce development time of applications such as nailing, drilling, laser cutting, plasma cutting, water jet cutting, routers, and lathes.

With its new release National Instruments Motion Assistant 2.0 adds the ability to directly import motion profiles created in CAD and drafting packages. NI Motion Assistant also features a patented Smart Contouring algorithm that allows machine builders to make faster moves and reduces machine ware. Motion Assistant is a stand-alone prototyping tool designed to speed up development of motion applications. It offers a configuration based interface to machine builders for developing and previewing motion applications without writing any code. Starting with version 2.0 Motion Assistant allows users to import two-dimensional CAD drawings using the popular DXF file format. Along with reducing development time the ability to import DXF files gives machine builders the flexibility to easily modify existing profiles or create additional profiles.


Figure 1. NI Motion Assistant speeds up development time by allowing machine builders to import motion profiles created in CAD and drafting environments using the popular DXF file format


Buy NI Motion Assistant 2.0

After importing a motion profile NI Motion Assistant allows users to configure move parameters such as velocity, acceleration and deceleration and lets them test their moves with real motion control hardware.

Once the move is thoroughly tested Motion Assistant can generate NI LabVIEW or C code required to deploy the application. NI Motion Assistant offers tight integration with NI motion controllers and gives machine builders the flexibility to precisely control steppers, brushed servos, brushless servos or piezo-electric motors. NI motion tools also offer integration with NI Vision and Data Acquisition tools and allow machine builders to create their application using a single tool chain.

See Also:
Download the Motion Control Fundamentals E-Kit
Download the NI Motion Assistant Evaluation Software

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2. Architecture Overview


There are two main ways to architect a motion system. The first architecture is a single system setup where the user does both the development and motion control on the same system. The system commonly is a PC or a PXI controller. This setup is typically used in laboratories. Figure 2 presents the architecture of a single computer system.


Figure 2. Architecture of a typical single system setup

The second architecture involves separate deployment and development systems. The development and deployment systems generally are either industrial PCs or PXI controllers. This setup is typically used when the user needs to deploy the motion control application to multiple targets. OEMs, integrators, and application builders use this architecture. Figure 3 presents the architecture of a deployment system.



Figure 3. Architecture of a Typical Deployment System Setup

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3. CAD File


The components featured in the Architecture Overview section are described in more detail below.

CAD files contain a sequence of moves created in a CAD application such as AutoCAD or SolidWorks. Motion Assistant supports two-dimensional CAD files in the following formats:
· AutoCAD 2004 DXF
· AutoCAD 2000/LT 2000 DXF
AutoCAD DXF (Drawing Interchange Format, or Drawing Exchange Format) is a CAD data file format developed as a solution for enabling data interoperability between AutoCAD and other programs. DXF files come in either an ASCII or binary format. Motion Assistant supports the ASCII DXF format.

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4. Motion Assistant


National Instruments Motion Assistant is a stand-alone configuration based prototyping tool for quickly developing motion applications. Motion Assistant takes guess work out of developing motion applications by offering a graphical interface to visualize the moves in 2 and 3 dimensions and monitor velocity and acceleration profiles. Motion Assistant allows users to construct and preview motion profiles without writing any code. Machine builders can create motion profiles in Motion Assistant using a combination of built in straight line, arc or contoured moves or by directly importing them from CAD files.


Figure 4a. Easily create straight line moves



Figure 4b. Add arc moves.


Figure 4c. Add contour moves

Motion Assistant allows users to generate LabVIEW or C code for further application development using the NI-Motion driver API. Users can also generate code recipes for the text-based language, such as C, C++, or Microsoft Visual Basic.

Starting with version 2.0, Motion Assistant allows users to import two-dimensional CAD files. Using the data in an imported CAD file, Motion Assistant creates a CAD move which contains a series of shapes consisting of combinations of the basic move types such as straight-line, arc, and circle.

If the profile contains disconnected shapes Motion Assistant automatically generates the path required to connect disjoint shapes and displays them as dotted lines. These added shapes, called Inserted Shapes, typically contain a single inserted straight-line move. Most cutting and drafting applications require the blade or drill to move out of the plane of the object being scribed when moving between two disconnected shapes. To accomplish this Motion Assistant features an automatic feature, called Pen Up/Down, which controls a third axis used to move the cutting assembly up or down. In the following position view diagram, the shapes are represented as solid lines and the inserted shapes are represented as dashed lines.



Figure 5. Motion Assistant automatically generates straight line paths between two disconnected shapes for a cutting tool to follow. The move sequence is user configurable.


Buy NI Motion Assistant 2.0

By default Motion Assistant sequences the moves in the same order as they were created in the CAD application. To optimize the cutting application Motion Assistant allows users to rearrange the sequence followed between different shapes. Machine builders can use this patent pending feature to increase the speed of their cutting or scribing application by re-arranging the cutting sequence so that the closest shapes follow one another.

Additionally, users can configure how Motion Assistant interprets units from the DXF file. A unit from the DXF file can be interpreted either as one revolution of the motor or as one count of the encoder. Users can configure the number of steps per revolution for stepper motors and encoder counts per revolution for a servo to translate the units to real world coordinates. For example, if one unit of the CAD file represents 1 cm the user can set the motion controller's number of steps per revolution to the number of steps that would make the motor move 1 cm.

Note:
Motion Assistant 2.0 is compatible with NI-Motion 7.0 and later. To create LabVIEW code from a Motion Assistant prototype, you must have LabVIEW 7.0 or later installed.

See Also:
Download the NI Motion Assistant Evaluation Software
10 Essential Technologies for High-Performance Motion Control

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5. XML


Extensible Markup Language (XML) is a markup language for documents containing structured information. XML provides a format to define tags and the structural relationships between them. An XML file contains data and tags that define the data. An XML schema file describes the structure of an XML file and defines the legal building blocks of the XML file.

When users generate code for a CAD move, Motion Assistant saves all move parameters into an XML file and uses the file in the application. For added flexibility machine builders can create XML files for each move the cutting machine needs to follow. These XML files can them be programmatically selected in the application to select the appropriate move making it extremely easy to change the functionality of the application.

Note:
The XML file can be manually edited or created for use in LabVIEW or C. If users choose to manually edit or create the XML file, it must comply with the provided XML schema. This file is located in the <Motion Assistant>\bin\mxwPlugins\XMLSchema\CAD.xsd directory.

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6. Programming Language


After prototyping the motion application users can use the code generation feature of Motion Assistant to generate code for LabVIEW, LabWindows/CVI, or C. Code recipes also can generated for other text based languages such as C, C++, or Microsoft Visual Basic.

The generated application can easily be modified in the development environment. Users also have the option to compile the application into an EXE and deploy it to one or more target machines.

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7. Motion Controller 


Motion Assistant 2.0 and higher can be used with any of the following motion controllers:
· NI 7350 Series Controllers
· NI 7340 Series Controllers
· NI 7330 Series Controllers
· NI PCI-7390 Controllers
· NI SoftMotion Controller - Copley Controls Corp. CANopen drives

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8. Conclusion


The Motion Assistant gives machine builders the ability to create motion profiles from a CAD drawing, generate modifiable code for the motion profile, and implement the motion profile on the drives and motors of their choice. For increased speed and reduced machine ware Motion Assistant offers the patented Smart Contouring feature. Motion Assistant provides added functionality, flexibility, integration, and value to many profile cutting and scribing applications. By using Motion Assistant and CAD files, machine builders can reduce costs, optimize moves, customize code, simplify applications and significantly shorten development time.
Related Links:
NI Motion Hardware
Download the Motion Control Fundamentals E-Kit
10 Essential Technologies for High-Performance Motion Control

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