TO WHAT EXTENT IS IT NOW POSSIBLE TO MODEL AND SIMULATE THE OPERATING DYNAMICS OF INDUSTRIAL MOTION SYSTEMS CONSISTING OF MULTIPLE MECHANICAL AND ELECTROMAGNETIC COMPONENTS?

Thomas • Bosch Rexroth: From a standpoint of available tools, a wide range of simulation is already possible. But the engineering level concerning how it must be used is still at a very academic level. No truly integrated packages exist that combine the necessary device libraries, which would allow an engineer to easily model and simulate a complete production system.

Steve • Rockwell: Current technologies allow for the modeling and simulation of highly complex industrial motion systems with multiple mechanical and electromagnetic components. Today's leading simulation packages provide libraries of core functions that let designers create the basic system building blocks. As these models are cascaded together with the other model components, entire machines and processes can be emulated to allow for total system simulation.

Synchronization methods are also available that allow plant model simulation to be coordinated with a model of the user's control system. By running the simulated control system in synchronization with the users' plant function, an entire system — from control to process — can be emulated, allowing for easy troubleshooting, diagnostics, and system design.

Marius • Ansoft: In general, the design and simulation of industrial motion systems is often compromised by the sheer complexity of the inherent subsystems: power generators, rectifiers, converters, and electromechanical and hydraulic loads. In the past, engineers attempting to simulate these systems have been stymied by the need for expertise and understanding of all the subsystems and their interactions. Overwhelmed by the complexity of the task, many engineers revert to an expensive “build and test” methodology rather than fully employing the power of simulation.

WHAT ARE SOME OF THE ADVANTAGES ASSOCIATED WITH SYSTEM-LEVEL SIMULATION FOR DESIGNERS AS WELL AS END USERS?

Marius • Ansoft: Components and systems must be tested in an environment emulating their intended use to enable refinement of system requirements, design decisions, and efficient resource utilization while ensuring that designs adequately address the operator's needs. System- level simulation provides a proven, cost-effective research capability. It will contribute significantly to the safety and success of the product design stage through virtual hands-on experience.

Steve • Rockwell: System-level simulation opens the doors to flexibility, exploration, and analysis of system design and system behaviors. Once individual components and functions have been proven and validated, each function can be used over and over again from one design to another. These components serve as the building blocks of the system design — and are all “paper designs;” they don't commit the designer or user to buying expensive pieces of machinery in order to determine if a concept will actually work.

By moving the various pieces around in a virtual reality, design, troubleshooting, and analysis are all possible without buying a single bolt or screw. This saves time and money, and provides an environment for experimentation that was not previously available to most in the industry.

Thomas • Bosch Rexroth: System-level simulation allows equipment designers to model and test different scenarios and alternative machine designs, and run complete tests to determine functionality and efficiency without wasting any hardware or machining and assembly time.

Reconfiguration of simulated systems as compared to real-life machines is easy and the risk for the involved equipment is close to zero. End users can use system-level simulation to build up machines and production lines on a modular base, and “play” with different approaches for a set production requirement. Production optimization can take place before real-life equipment even exists.

System-level simulation also has great potential for training and education. With completely simulated machines, operators, programmers, and service personnel can be trained on new machines or for new production processes prior to working with real equipment.

WHAT ARE THE MAIN CHALLENGES THAT INDUSTRY MUST OVERCOME BEFORE SYSTEM-LEVEL SIMULATION IS A COMMON PRACTICE?

Marius • Ansoft: The creation of simulation tools for mixed-signal, multi-domain systems, and multi-level modeling is challenging because these systems span the physical domains of electrics, magnetics, thermal, fluidics, and mechanics, as well as transient, frequency, and quiescent analysis within an unique environment. The difficulties are compounded by the fact that computational performance and simulation accuracy are directly related to the level of detail in underlying models.

VHDL-AMS modeling language addresses this, facilitating multi-domain and multi-level simulation. As more engineers become familiar with the language and the modeling process, the more common accurate system-level simulation will become. This process is well under way in the automotive and aerospace industries.

Thomas • Bosch Rexroth: As long as software specialists have to spend significant time marrying different tools to be able to reuse data, or have different simulation tools talk to each other, the time and cost involved in system-level simulation will remain prohibitive for many OEMs. Acceptance will dramatically increase as soon as integrated software packages allow design and production engineers to generate a close-to-reality simulation result with a few mouse clicks.

Part of the challenge is the availability of component data describing properties and dynamic behavior in an interchangeable format. Users of system simulation tools depend on readily available data for the system they are going to model and simulate.

Steve • Rockwell: There are several challenges to the adoption of system-level simulation. Although the use of simulation can save a lot of time and money once models have been proven and validated, the cost of initial validation can be high. This is because validation is the proving of the design in the final hardware and software implementation.

As actual machinery and product are developed, flaws and oversights in system modeling become apparent. As these differences in the simulation are discovered, an iterative process of refining the model occurs, which allows designers to create models with higher fidelity and more accurate representations of reality. This process can be expensive for first-time implementers, and the cost of the modeling itself might appear as an incremental cost on top of the machine design during initial trials.

Another barrier to system-level adoption across the industry is standardization. Models developed by one company may not be usable by another. A simple example is the modeling of a common switch: In model A, the switch is either on or off, but in model B, there is a need to know how long the contacts bounce or how many times they bounce so that reasonable filters can be applied. At some point, the industry may move simulation into a standardization process to define specific levels of fidelity and formats for common components.

WHAT NEW OPPORTUNITIES WILL EMERGE WHEN SYSTEM-LEVEL SIMULATION IS COMMONPLACE, ESPECIALLY IN TERMS OF MOTION-CENTRIC PROCESS DESIGN AND OPTIMIZATION?

Marius • Ansoft: The next frontier for system simulation will be real time simulation. Real time evaluation of a physical system is a significant challenge and requires advancement in computer technology as well as software algorithms. Beyond that comes real time optimization of system performance. This will create a true virtual prototyping capability allowing hardware, software, and simulation models to co-exist on the same platform.

Steve • Rockwell: As simulation becomes more commonplace, models will become more common among users, designers, and suppliers of machinery and control. Models will be shared among these participating members, and soon data sheets will be replaced by models available online. Design cycles will be greatly reduced.

Business opportunities will emerge between OEMs and control suppliers. As models are shared, intellectual properties will be merged to create competitive sub-systems that require both mechanical and electrical modeling and knowledge sharing. Partnerships with end users will also become tighter due to a similar need to share process modeling as an integral component of the machinery that runs it.

DESCRIBE A SCENARIO OF HOW DESIGNERS WILL SOMEDAY EMPLOY SYSTEM-LEVEL SIMULATION BEYOND WHAT'S POSSIBLE TODAY, AND THE BENEFITS THEY WILL ENJOY.

Marius • Ansoft: System analysis tools, simulation laboratories, human factors research tools, and distributed/collaborative workspace expertise will combine to form a unique system-level modeling and simulation capability. Based on continuous enhancements in computational speed, system-level simulation tools will create revolutionary real time decision-making tools for aerospace, automotive, and defense.

Steve • Rockwell: As the threads of simulation draw industry members tighter, the process of design will become more distributed. Control suppliers will define models for drives and actuators, which will be absorbed by OEMs into their mechanical designs; OEM designs will then be assimilated into end user designs for process design implementation. All of this will be networked via the Internet in a seamless fashion.

For more information and some bold predictions on the direction of system-level simulation, visit motionsystemdesign.com's Knowledge FAQtory and look for links that will connect you to exclusive content related to this article.

Meet the experts

Marius Rosu
Ansoft Corp.
ansoft.com

Thomas Fey
Bosch Rexroth Corp.
boschrexroth-us.com

Steve Zuponcic
Rockwell Automation
rockwell.com