Kinematics software like NEiMotion can virtually determine forces, stress, deformation, fatigue, and life. Applications include suspension systems, construction equipment, robotics, production fixtures, hand tools, and office chairs.

Picture a classic four-bar mechanism. With a basic spreadsheet, some knowledge of complex numbers, and input information, you might plot output acceleration and speed in a couple hours. But what if geometry changes, or the full three-dimensional situation needs analysis? Here, kinematics software makes building models infinitely easier. Increased connectivity is even allowing the placement of specific component profiles into models, and VRML and OpenHSF web viewing. And if our supposed one-degree-of-freedom system might actually be deforming under load, finite element analysis (FEA) can make our model highly realistic.

That's why everyone from Fortune 500 companies to individual consulting engineers is using analysis software. "It's very popular with consultants and designers, because it allows them to do the same things that larger competitors do — allowing them to design in areas where they might not have been able before," says Bob Williams, product manager, ALGOR Inc., Pittsburgh.

Kinematics put to sophisticated use

A Bourdon tube pressure gauge modeled and analyzed with ALGOR's Mechanical Event Simulation software shows the motion of the indicator needle as pressure increases within the tube — and resulting von Mises stresses.
Courtesy Noran Engineering

Returning to our four-bar example: Once mates are defined in a CAD assembly, kinematics software, which holds all links rigid, can animate the model. In the past, this was basic stuff. But now, more software is allowing designers to enter parameters like motor speed and motion for full inertial conditions. Output is generated as equations describing power requirements and joint reactions. The trajectories of motion can verify the movements of industrial robots, test tool paths, establish power requirements, and more. Simulation results can also be used to design systems in reverse, by converting trajectories to create new part geometries — for cam profiles, for example.

Cross-connectivity goes one step further in the development of mechatronic parts. In typical machine design, builders get requirements for a new project, design a controls scheme, and mechanical and structural engineers build the physical machine — and then the controls engineer implements his logic onto the machine to see if it works. "But with mechatronics toolkits, you can test controls algorithms even before any physical model is built," says Hari Padmanabhan, of SolidWorks Corp., Concord, Mass. To illustrate: Design & Assembly Concepts, Inc., Leander, Texas, recently used mechatronics software tools for motion optimization and collision detection on a solder tin dip machine to fully integrate their controls, programmed through LabVIEW (of National Instruments Corp., Austin) with SolidWorks and COSMOSMotion within the program.