Simulators, Optimizers

Machine design concepts improve automation and controls simulation

Virtual design tools and automation software intersect to save time and costs in machine commissioning so engineers can spot potential flaws before implementation.
By Daymon Thompson April 8, 2019
MathWorks Matlab/Simulink environments enable the design and simulation of new applications, such as this hexapod, as well as advanced algorithms that can be used in the machine controller to control the physical hexapod. Courtesy: Beckhoff Automation

Fast-moving product development efforts demand rapid improvements in controls engineering and manufacturing processes. Corporate initiatives often place responsibility on controls engineers to accelerate time to market, complicating this dynamic. Many design tools are available to help speed engineering efforts. These include a few technology milestones such as the introduction of computer-aided drafting (CAD) on the mechanical side, and programmable logic controllers (PLCs) on the control side. While these increased the speed and performance of machine designs, individual systems must integrate with other technologies to realize a new manufactured product or a functioning machine.

Systems and tools used in engineering and design also need methods to test new projects in a digital space. The next great improvement to engineering and design is automation and controls simulation, which provides the ability to start testing and commissioning machines very early in the process, such as before or during delivery, or during fabrication of the initial mechanical components.

Modern control system development software should be part of the first step in simulation. These engineering environments permit the simulation of scalable control code on the engineering PC without the need for a hardware controller in the design phase. This code also should run in real time, meaning if the PLC code has a 1-ms update cycle, it should be simulated at 1 ms. Running a different update rate might prevent the programmer from identifying potential timing or “race” conditions of multiple tasks. Simulation capabilities extend beyond the PLC to incorporate motion system design, as well. While all programmers can benefit from cleaner code earlier in the process, advance motion programmers working on kinematics, gearing and advanced cam tables can write, test and debug code before purchasing any motors or drives.

CAD considerations for effective simulation

Once the PLC and motion control simulations are in place within the engineering and programming environment, the next integration test is running them with plant/facility models and CAD tools that allow 3-D machine and system simulation. Creating a digital link that connects the controls engineering environment, simulation software and a 3-D CAD or emulation system does this. The aim of this connection is a software-in-the-loop (SIL) simulation of the intended sequence on a machine or system to support virtual commissioning.

The 3-D simulation of machine and system components is a key element when implementing virtual commissioning. In the simulation, the movements and interactions of all individually installed components are represented in combination in order to predict collisions and critical system states in advance. Simulations also can be used before the machine is completed to train operators and maintenance personnel for regular operation and to learn troubleshooting instructions based on simulated critical machine states.

For software-in-the-loop (SIL) simulation, the intended machine or system processes are first created and simulated in Matlab/Simulink software by MathWorks with convenient drag-and-drop functions for use in configuring and parameterizing links, before being run in real-time with PC-based automation software. Courtesy: Beckhoff Automation

For software-in-the-loop (SIL) simulation, the intended machine or system processes are first created and simulated in Matlab/Simulink software by MathWorks with convenient drag-and-drop functions for use in configuring and parameterizing links, before being run in real-time with PC-based automation software. Courtesy: Beckhoff Automation

When the processes are run on PC-based automation software in real-time at real process update rates, Simulink from MathWorks continues to monitor machine or system performance through the digital link connecting it to the controls engineering environment and a 3-D CAD or emulation system. Courtesy: Beckhoff Automation

When the processes are run on PC-based automation software in real-time at real process update rates, Simulink from MathWorks continues to monitor machine or system performance through the digital link connecting it to the controls engineering environment and a 3-D CAD or emulation system. Courtesy: Beckhoff Automation

Modern simulation tools feature convenient drag-and-drop functions for use in configuring and parameterizing links. Complex relationships can be mapped between software tools. SIL simulation of machines, systems, and installed components is easy and convenient, even with future system expansions.

Factor in Fieldbuses and networking

The goal of any virtual commissioning simulation is to represent the machine or process with an accurate model. However, many virtual commissioning systems do not account for the Fieldbus or networking technology in the application. Testing and commissioning of a real system would never be complete without checking for a fully functional Fieldbus. Simulation or virtual commissioning should be included, as well.

With EtherCAT industrial Ethernet technology, complete virtual machine commissioning becomes possible by connecting the machine controller to a computer running the simulation via an Ethernet cable without requiring reconfiguration of the machine controller. With EtherCAT simulation functions available in PC-based control software and a standard network adapter, the simulation computer can simulate connected EtherCAT slaves.

For configuration purposes, the architecture of the EtherCAT slaves from the original machine configuration is inverted. All EtherCAT features necessary for machine simulation are modelled—including distributed clocks for highly precise device synchronization. Since CAN Application Protocol over EtherCAT (CoE) and Servo Drive Profile over EtherCAT (SoE) are implemented, acyclic commands also can be processed in the simulation environment.

MathWorks Matlab/Simulink environments enable the design and simulation of new applications, such as this hexapod, as well as advanced algorithms that can be used in the machine controller to control the physical hexapod. Courtesy: Beckhoff Automation

MathWorks Matlab/Simulink environments enable the design and simulation of new applications, such as this hexapod, as well as advanced algorithms that can be used in the machine controller to control the physical hexapod. Courtesy: Beckhoff Automation

During machine design, it also is possible to simulate the full Fieldbus network in real time. This approach provides actual network update rates to accurately size the controller CPU needed for the application. This ensures engineers will need to switch to a bigger processor when physically commissioning the machine. This also maintains the appropriate machine control performance level and keeps overall equipment costs under control.

Real-time HIL, SIL simulations

Engineers can create advanced algorithms with simulation software environments and run them in real-time with PC-based control software. Machine control projects simulated in PC-based control platforms also can be used for SIL real-time simulation. Using a software connector to the simulation software, it is possible to read and write real-world sensor and actuator data. This allows the simulation software model to operate on real information and enables hardware-in-the-loop (HIL) simulation of the software model.

Virtual commissioning, real engineering efficiency

Control system simulation and virtual commissioning can yield significant savings in all machine and plant design stages. Using simulation software to identify and resolve flaws in mechanics, controls and programming helps engineers work “smarter, not harder.”

Daymon Thompson, automation product manager, North America, Beckhoff Automation. Edited by Chris Vavra, production editor, Control Engineering, CFE Media, cvavra@cfemedia.com.

MORE ANSWERS

Keywords: Simulation software, machine design

Modern control system software should be the first step in simulation.

The goal of any virtual commissioning simulation is to represent the machine or process with a completely accurate model.

Control system simulation and virtual commissioning can create savings in all machine and plant design stages.

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What benefits could your plant gain from simulation software?

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Daymon Thompson
Author Bio: Automation product manager, Beckhoff Automation