Motion System Simulation Pays Off in Many Ways

Online Extra to August 2001 Control Engineering article on 'Motion Simulation.'

By Frank J. Bartos, CONTROL ENGINEERING August 1, 2001

S oftware is ubiquitous. Perhaps in no sector is it more visible than product design, where essentially all of today’s industrial products reach reality with the help of computer-aided design (CAD) tools. However, many products, especially those involving complex motion, require more detailed scrutiny of how well the design will work.

This is where simulation software comes into play. Simulation can provide a ‘virtual prototype’ of the product or machine before a physical model is built. Simulation can also cut down on costly physical testing though not entirely eliminate it.

Several other benefits of simulation for motion systems are discussed in the main article. Simulation through software also can help maintenance personnel upgrade documentation available for servicing their equipment. Animation and exploded-view formats within the software offer valuable guidance. According to Aaron Kelly, product manager at SolidWorks Corp. (Concord, Mass. ), ‘Parts ‘flying in space’ from an exploded-view simulation can be worth many pages of complex service instructions.’

And the market for simulation software is growing. Daratech Inc. (Cambridge. Mass. ) a market research and technology assessment firm specializing in CAE and related software sectors pegs the market for virtual prototyping and simulation at $1.3 billion in 2001. This represents a growth of 19.2% over year 2000. ‘Driving this growth is the urgent need of manufacturers to compress product cycle times and time to market, simultaneously boost product quality to reduce recalls and warranty expenses, while lowering product development costs,’ according to Daratech.

To help define the evolving role of virtual prototyping, Daratech will present a conference on this topic. Scheduled for October 29-30, 2001, in Novi, Mich., daratechIPS2001: Intelligent Prototyping Strategies, also will look at the interaction between physical and virtual prototyping, as well as business and technology issues of investing in these areas. More information about the conference is available at the company’s web site or from Tom Greaves, executive vp of marketing at Daratech ( ).

More suppliers, many partners

The half dozen companies mentioned in the main article represent core suppliers of mechanical system and motion simulation software. Others also supply this dynamic marketplace, and numerous partnerships and alliances exist among the various companies. Here is a sampling of other suppliers.

PTC (Needham, Mass. ) offers Pro/Mechanica as a ‘family of functional simulation solutions.’ Motion Simulation Package one of three packages available allows designers and engineers to evaluate and optimize the kinematic and dynamic performance of moving assemblies. Each simulation package includes Pro/Mechanica Foundation, configured as either stand-alone applications or integrated options to the company’s main product development software, Pro/Engineer.

The Boeing Co. (Seattle, Wa. ) has commercialized a software package called Easy5 that includes simulation and virtual prototyping, as well as control system design and analysis. Easy 5 contains an extensive set of predefined modeling blocks that simplify and speed up the simulation process. Modeling blocks (said to number in the hundreds) address hydraulic, thermal, pneumatic, automotive engine/powertrain, mechanical, electrical, and control system applications. A free demonstration CD and User Guide are available from Boeing.

Dynamic Analysis Design System (DADS) is another software package for multi-body mechanical system simulation. DADS is a product of LMS International (Leuven, Belgium ). The software transited to LMS through its acquisition of CADSI Inc. of the U.S. in 1998, which is now part of LMS CAE Division. Capabilities of DADS include dynamic, kinematic, static, and inverse dynamic analyses that go beyond simpler simulations found in CAD software. DADS has a wide range of applications, with automotive, engine, and aerospace solutions among them.

Lumeo Motion is a software module from Lumeo Software Inc. (Espoo, Finland ) intended to simulate motion dynamics of rigid multi-body systems. The software reportedly provides rapid, interactive analysis of design concepts, while the system or subsystem is made to ‘move under the laws of physics.’ The user defines geometry, material and mass properties, initial forces, etc. in the associated CAD software.

VisSim/Motion is a product of Visual Solutions Inc. (VSI, Westford, Mass. ) that simplifies motion/motor control system modeling and simulation through use of 40 built-in motion blocks. The library of motion control blocks includes motors, amplifiers, dynamic loads, encoders, sensors, controllers, etc. Users select and connect the elements, then run a simulation and see the system’s behavior just by pushing a button, according to VSI. Tutorials describe how to model and simulate motion control systems with ac induction and dc brushless motors. VisSim/Motion is based on VSI’s core software product, VisSim.

Other simulation

A gamut of software exists to model, analyze, and provide graphical design solutions for motion system products. These tools include an ‘analytical type’ of simulation applicable to such items as robot mechanisms, electrical circuits, magnetic circuits, motors and drives, etc. The following are examples of such software tools.

Available from Ansoft Corp. (Pittsburgh, Pa. ), Simplorer is a simulation package that aids the design of complex power electronics and drive systems. Users have a choice of three modeling languages: electrical circuits, block diagrams, and state machines. Animated symbols help visualize system states during the simulation. Simec GmbH & Co. KG (Chemnitz, Germany ), which is now part of Ansoft Corp., developed Simplorer software.

Another example of software to analyze/simulate power electronics for motor drives is Caspoc from Simulation Research (Alphen aan den Rijn, Netherlands ). Caspoc works on multiple analysis levels (component, circuit, and system) that respectively suit modeling of motors and their loads, power supplies, and control algorithms.

Infolytica Corp. (Montreal, Quebec, Canada ) offers MagNet 6, a software tool that uses 2D and 3D solvers for electromagnetic simulation of low-frequency devices. Typical applications include various electric motors (induction, switched-reluctance, brush dc, and brushless dc), actuators, levitation systems, magnetic bearings, loudspeakers, and electromechanical shakers. For high-frequency devices, a 3D tool called FullWave is also available.

Developed at the SPEED Laboratory of the University of Glasgow (Scotland), a series of software tools is said to provide fast interactive design and performance calculations of various electric motors. Classical theory and equivalent circuit models are used in the design simulation. Four separate SPEED modules address brushless permanent magnet (PM) motors/generators and PM self-synchronous machines; switched-reluctance motors/generators; ac induction motors; and PM dc motors. Motorsoft Inc. (Lebanon, O. ) distributes SPEED software exclusively in the U.S.

On the web?

As mentioned in the main article, doing simulation online comes as no surprise. Other areas of software have a large and growing Internet presence. However some special constraints apply to implementing web-based simulation.

Foremost is the concern for security when running software on the web. This includes exposure of the CAD files, on which realistic simulations are based, and the associated design details, physical and material properties of the product, etc. Design data represent extremely closely guarded corporate property.

Practicality of doing simulations on the Internet also depends on the complexity of the part or system. Model files can become very large, complicating their handling and movement. Size of the model file brings in network issues and, most likely, locating the web server remote to the user’s site. This in turn brings up the issue of protecting design data and model information that resides on an external server.

No doubt these issues will receive proper hearing and debate over time. User and market acceptance will determine the extent of software simulation done online.

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