Integrating Industrial Robotics with CAD

19 Mar, 2008 By: Jeffrey Rowe

The market is taking small steps toward a more seamless solution for developing these reprogrammable devices.

Robotics -- building reprogrammable devices to perform a variety of tasks -- is an expanding, seemingly limitless field. Its popularity extends to everything from kids' toys such as LEGO Mindstorms and the VEXplorer, to robotics competitions such as FIRST for students, to industrial robots from companies such as FANUC and ABB -- just to name a few. These applications obviously span several levels of complexity; nonetheless, they share several things in common because all are mechatronic in nature and involve several other types of interoperable subsystems, including electronics, sensors, controllers, and software.

In this edition of MCAD Tech News, I'll delve into the world of industrial robots used for manufacturing processes and their relationship to the computer-aided design (CAD) process.

Robotics Basics
The advantages of industrial robots are well known. These robots can produce highly precise, repeatable, consistent work; increase throughput speeds; and perform in hazardous environments. What you don't hear so often are some of the potential drawbacks of industrial robots, including the initial investment and ongoing maintenance costs; extensive training required for employees who program and operate the robots; and the careful planning required to actually improve productivity and quality. Simply installing robots does not guarantee success! Examining and understanding how CAD fits into the automated process is a vital part of implementing industrial robots and ensuring success.

CAD, CAM (computer-aided manufacturing), and CAE (computer-aided engineering) are all familiar acronyms in our field. A number of years ago another acronym emerged: CAR (computer-aided robotics), which was software for designing, manufacturing, installing, and programming industrial robots. ROBOCAM and CimStation were two major CAR packages, but neither survived. Today, CAR software has been replaced by CAD software for robot design, CAM for manufacturing, CAE for simulation, and other packages for programming controllers and process/workflow on the factory floor.

A robot's most basic practical functions and considerations include:

  • Movement: How will the robot move within its space?

  • Manipulation: How will the robot move and manipulate other objects within its environment?

  • Intelligence: How does the robot "think"?

  • Sensing: How will the robot "know" where it is and what's in its environment?
Basic though these individual considerations may be, they become very complex taken collectively.

I'm really surprised, however, that another developer hasn't ventured into the market with a comprehensive software package for designing, programming, and deploying robots. I attribute this to the fact that industrial robots have become so specialized and complex in their electromechanical and programming subsystems, that developing software that can perform all the required tasks is daunting. And although it's seemingly increasing, the potential customer base remains small. Still, I wonder if such solutions are possible, considering overall mechanical structure, gear combinations, arm mechanisms, sensor placement, electronics, programming, and so on?

If it's too tall an order to hope for a specific solution for industrial robotics product development, how about an add-on for an existing CAD product? As it turns out, such a product does exist. RobotWorks is a robotics interface for programming and simulating robotic movement with SolidWorks. RobotWorks is available as an add-on to SolidWorks or as a stand-alone package with SolidWorks integrated inside it -- sort of an inside-out or outside-in implementation, whichever fits best. RobotWorks' approach is, "Let the part drive the robot." It uses the "intelligence" built into SolidWorks parts and assemblies to generate a robot's trajectory for work cell design, motion simulation, and robot programming.

Working with industrial robots today is similar to the situation about 10 years ago when computer numerically controlled (CNC) programming required special operator knowledge and manually "teaching" a machine what to do. Today's CNC programs have largely eliminated that requirement, and machines are programmed directly from a graphics-based CAD/CAM environment and include the ability to design parts and fixtures, visualize toolpaths, and perform simulations. Moreover, smart CNC programs analyze the part itself, recognize features, and create smarter and more efficient toolpaths.

CNC programs are no longer written one line at a time; however, today's industrial robots are still often programmed that way. But this is rapidly changing with applications such as RobotWorks.

RobotWorks uses the graphics and kinematics engine in SolidWorks to create a robot trajectory (motion path) along faces, edges, and curves of CAD objects. In RobotWorks, the geometry of the objects created in SolidWorks is translated to a mathematically accurate path, complete with location and orientation, along which a robot can operate. It reads x, y, and z points, translates them to the robot path, and records external events and instructions (I/Os, speed, etc.) for each point for performing specific tasks.

The software produces an accurate off-line robot program written in native robot language for robots from ABB, FANUC, KUKA, Motoman, and others. Once you create a trajectory path, you can move parts around on the screen and the path is automatically revised, or you can modify parts manually. RobotWorks supplies the robot models, and you can load assembly parts and fixtures from your parts libraries, import them from other CAD programs, or create them inside SolidWorks.

Where We Stand Today
Robotics development capabilities may some day become more integrated in CAD. In the meantime, some CAD packages now on the market -- specifically, SolidWorks -- do offer features and capabilities that can apply. Such solutions support the process known as design for manufacture (DFM). DFM focuses on the cost and difficulty of making a product. At a simple level, DFM addresses manufacturing details, such as ensuring that a pin can be assembled into a hole, either manually or automatically. At a more complex level, DFM tackles the problem of determining product structure and form and involves fundamental design for assembly (DFA) considerations.

As robotics plays an increasingly larger role in manufacturing, expect to see CAD packages that take DFM a giant step further, facilitating design for automated manufacture. The potential for boosting productivity and quality, while reducing overall product cost and complexity, is enormous.

CAD and robotics are intimately intertwined in the burgeoning field of mechatronics, a topic that I will explore in detail in the coming weeks and months.

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