Intense global competition is putting pressure on machine builders to deliver machines with higher throughput, reduced operating cost, and more features. But it is not only about improving productivity. Rising energy costs and increasing environmental awareness are causing engineers to focus on designs that increase efficiency and lower energy consumption. Therefore, today’s machine builders have switched from designing single-purpose machines to creating flexible and highly effective multipurpose machines by adopting modern control systems and sophisticated algorithms and integrating high-end electronics into their mechanical machine.
The trend toward effective multipurpose machines dramatically increases design complexity and forces different design groups to work closer together. In the design of a modern machine, every decision has a ripple effect throughout the design. If the mechanical team decides to change the material and therefore the weight of a mechanical component, it has an influence on the motor sizing or sometimes even on the type of motor needed to efficiently operate the machine. Switching from a stepper motor to a servo motor significantly increases the complexity of the control algorithm and the requirements concerning the system performance of the embedded system processing the algorithm. Improving team communication and collaboration between mechanical, electrical, and control engineers is crucial and tools that offer seamless integration and help them share data and information throughout all phases of the development cycle lead to vivid collaboration.
1. Applying Digital Prototyping to Facilitate a Mechatronics Design Approach
Mechatronics represents an industry-wide effort to improve the design process of modern machines by integrating the best development practices and technologies to streamline design, prototyping, and deployment. According to Dr. Kevin Craig, Professor of Mechanical Engineering at the Rensselaer Polytechnic Institute, mechatronics as an engineering discipline is the synergistic combination of mechanical engineering, electronics, control engineering, and computers, all integrated through the design process. It involves the application of complex decision making to the operation of physical systems. Mechatronics highlights a growing trend of cooperation between different design teams that is necessary as designs become more complex.
One technology that facilitates the mechatronics approach is digital prototyping. This technology gives design, engineering, manufacturing, and sales and marketing teams the ability to virtually explore a complete product before it is built. Engineers and scientists use digital prototyping to design, optimize, validate, and visualize their products digitally and evaluate different design concepts before incurring the cost of physical prototypes. Digital prototyping goes far beyond creating 3D CAD models. It gives design teams a way to assess the operation of moving parts, to determine if the product will fail, and see how the various product components interact with subsystems. By digitally simulating and validating the real-world performance of a product design, manufacturers significantly reduce the number of physical prototypes and change the traditional product development cycle. Whereas in the past they went through the stages of “design, build, test, and fix,” they now take an approach of “design, analyze, test, and build.” Using these new tools, they overcome the need to build multiple physical prototypes.
At the same time, engineers can use digital prototyping to develop highly efficient systems in which motor and actuator size are perfectly matched with the requirements of the mechanical structure. While most motor vendors provide tools for choosing the motor to fit a specific need, the information those tools require is difficult to figure out. The mathematical formulas describing a dynamic system are anything but easy. In the past, engineers often chose motors based on limited information and over-engineered the motors by adding security margins. Digital prototyping tools offer the capability to simulate the dynamic behavior of the whole system in advance, including the motors and even the control algorithms, and collect all the necessary information to pick the right motors. Most of the parameters required to perform the simulation are reused from other development steps and merged from different design tools.
2. The Integration of NI LabVIEW and SolidWorks
To help lower the cost and risk of machine design, SolidWorks and National Instruments are collaborating to provide digital prototyping tools for motion control system designers.
By connecting the SolidWorks motion analysis capabilities to the National Instruments LabVIEW 2009 NI SoftMotion Module and using the motion control programming functions to drive the simulation within SolidWorks, you can create realistic simulation of your motion control systems. To realize the connectivity between those two design tools, the LabVIEW project offers the capability to add an existing SolidWorks 3D CAD model to the project tree and automatically populates the motors and sensors defined within the model. You can use the high-level motion functions provided by the LabVIEW NI SoftMotion Module to develop your motion profile from single-axis to complex coordinated motion. By simply running a motion application, LabVIEW drives the simulation within SolidWorks. You can use all the SolidWorks features to visualize and analyze your application or send data back to LabVIEW for further analysis.
Figure 1. The seamless integration of the LabVIEW 2009 NI SoftMotion Module and SolidWorks software delivers a programming environment that is ideal for digital prototyping.
With these tools, mechanical and control engineers can begin working together as soon as the CAD model has been created. They can use digital prototyping tools to create a realistic simulation of the machine for use in a variety of design analysis purposes:
- Visualize realistic machine operation
- Estimate machine cycle time performance
- Perform accurate force/torque requirements analysis
- Design and validate motion control programming and detect collisions
- Optimize the design before building a physical prototype
- Identify design issues across mechanical/electrical boundaries
Using SolidWorks and LabVIEW, motion system designers can simulate mechanical dynamics, including mass and friction effects, cycle times, and individual component performance, before specifying a single physical part. Integrating motion simulation with CAD simplifies design because the simulation uses information that already exists in the CAD model, such as assembly mates, couplings, and material mass properties.
Finally, you can easily deploy the motion application developed and validated using the 3D CAD model to embedded motion control platforms such as NI CompactRIO hardware. Using the new NI 951x C Series drive interface modules, you can apply the algorithms to a physical prototype or the final machine through the direct connectivity from the C series modules to hundreds of stepper and servo drives and motors. Therefore, you can reuse the code developed and tested within the simulation and hook it up to physical I/O and motors.
Figure 2. NI SoftMotion and new C Series drive interface modules for CompactRIO dramatically simplify motion application development.
Best-In-Class Machine Designers Use Digital Prototyping Tools
An independent study of the Aberdeen Group shows that by using a mechatronics approach and digital prototyping tools, best-in-class machine design companies can exchange more iterations on simulation for fewer physical prototypes and test cycles and shrink the development time by 12 to 40 days. Through simulation, those companies collect a lot of information in an early design phase, which gives them the possibility to improve their design, identify risks, and optimize the efficiency of their final machine.
Christian Fritz is the product marketing manager for motion and mechatronics at National Instruments. He holds an engineering degree from the University of Applied Sciences in Munich, Germany.