Lowering the cost and risk of machine design

Lowering the cost and risk of machine design

Integrated, multidisciplinary tools are required to get it right the first time with today’s complex electromechanical systems

BY CHRISTIAN FRITZ
Senior Product Manager
National Instruments
www.ni.com

Intense global competition is putting pressure on machine builders to deliver machines with higher throughput, reduced operating cost, and more features that improve productivity, increase efficiency, and differentiate their machines from the competition. For this reason, 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 as well as integrating high-end electronics into their mechanical machines.

A mechatronics refresher

Mechatronics represents an industry-wide effort to improve the design process by integrating the best available development practices and technologies to streamline design, prototyping, and deployment.

According to Dr. Kevin Craig, the Robert C. Greenheck Chair in Engineering Design and Professor of Mechanical Engineering at Marquette University, mechatronics, as an engineering discipline, is the synergistic combination of mechanical engineering, electronics, control engineering, and computers — all integrated through the design process (see Fig. 1 ). It involves the application of complex decision making to the operation of physical systems.

For their unique functionality, mechatronics systems depend on computer software. This discipline highlights the growing trend of the cooperation among different design teams that is necessary as designs become more complex.

Fig. 1: It is the integration of multiple disciplines that creates the discipline of mechatronics.

Mechatronics’ success

The trend toward mechatronical systems increases design complexity dramatically and forces different design groups to work together more. In a mechatronical system, every decision made 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 impact 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 the tools that offer seamless integration and help engineers share data and information throughout all phases of the development cycle enable vivid collaboration and exchange of information.

Quintessentially, those tools allow the implementation of a virtual prototype (also known as a digital prototype) that combines simulations from all different domains — a single model to simulate the complete machine or device. Designers can simulate mechanical dynamics, including mass and friction effects, cycle times, and individual component performance, before specifying a single physical part. A virtual prototype offers the ability to visualize and optimize the design and evaluate different design studies and concepts before incurring the cost of physical prototypes. A mechatronics-based approach lowers the risks associated with machine design, speeds the design process, improves understanding of customer requirements, and streamlines debugging. The mechatronics approach helps machine builders get it right the first time.

From a business perspective, a virtual prototype adds a lot of value to the design phase and supports the sales department in the communication with potential customers throughout the selling process. A virtual prototype can help sales win business and successfully execute projects.

Within the quoting phase, a virtual prototype helps define the requirements and ensures that the sales department understands customer needs correctly. It offers the possibility to show design features and explain the value and helps uncover the unknowns within a project and measure risks. Even in the after-sales process, a virtual prototype can be useful when working on improvements and testing upgrades customers want to add to machines that are already deployed. In addition, customers can use this prototype to resolve issues they encounter during operation.

LabVIEW/SolidWorks integration

To help lower the cost and risk of machine design, Dassault Systèmes and National Instruments are collaborating to provide mechatronics-oriented virtual prototyping tools for motion control system designers. With LabVIEW and SolidWorks, machine builders can create realistic simulations of motion control systems by connecting SolidWorks motion analysis capabilities to LabVIEW industrial-grade motion control programming functions.

Using this integration, machine builders can develop the control logic and motion profiles and apply them to the 3D CAD model of their machines to test the operation of the machines in software before paying expensive tooling costs and purchasing physical components (see Fig. 2 ). With this integration, machine builders can evaluate system behavior and performance before building a physical prototype. They can test electrical performance and real-time response times at operational extremes without stressing a part.

Fig. 2: Combining well-established software tools LabVIEW with SolidWorks makes the task of integrated design faster and more reliable, while also allowing control algorithms to be rapidly deployed in end products.

Because of this, mechanical engineers and control engineers can begin working together as soon as the CAD model has been created. They can use virtual prototyping tools to create a realistic simulation of the machine that can be used for 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, engineers can simulate mechanical dynamics, including mass and friction effects, cycle times, and individual component performance before specifying a single physical part and connect it to an actual control algorithm. Virtual prototyping offers the ability to visualize and optimize the design and evaluate different design concepts before incurring the cost of physical prototypes.

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. LabVIEW provides an easy-to-use, high-level function block programming language for programming the motion control system that is easy enough for users with little or no previous motion control programming experience.

The LabVIEW integration with SolidWorks helps customers develop their motion control algorithms and use the 3D CAD model created within SolidWorks to evaluate system behavior and performance. By applying realistic motion control, it is possible to simulate real-world operating conditions for the design, check for colliding parts, output the numerical and graphic data of the results, and use the CAD model for 3D visualization.

Finally, engineers can easily deploy the control algorithms developed to embedded motion control platforms such as NI CompactRIO, a rugged FPGA-based hardware platform. CompactRIO provides a real-time embedded processor for stand-alone and distributed deterministic operation and industrial hot-swappable I/O modules for direct connection to industrial sensors, actuators, and motors. With CompactRIO, engineers can reuse the code developed and tested within the simulation and hook it up to physical I/O and motors.

Additional resources

For Virtual Prototyping, you can explore different tools and resources for designing and prototyping mechatronics systems using LabVIEW and graphical system design at www.ni.com/virtualprototyping/.

Toview more information, case studies, tutorials, and demonstrations on control design, modeling, and simulation using LabVIEW, visit www.ni.com/embeddedsystems. ■