Development of Linkage Analysis and Synthesis Software

Jiao Zhang
Caterpillar, Inc.

Linkages are widely used in agricultural and construction machinery as well as in all kinds of industrial equipment. Design of different linkages becomes more and more challenging in today's market because customers always expect similar-size machines that can carry more load, move faster, and reach further. To optimize the linkage-development process, the application of more advanced computational technology and design philosophy is essential and inevitable. Symbolic analysis, in addition to numerical analysis, provides us with the most powerful tool for product development in the linkage-design area. In symbolic analysis, the properties of the linkage system and its design specifications in all areas of kinematics, statics, and dynamics may be represented as a set of symbolic formulas and equations that are the functions of design and operational parameters. With full capability to manipulate formulas and equations symbolically, we may conduct linkage-performance analysis, comprehensive sensitivity study, and design synthesis much faster and easier. Recently, a SNAS (Symbolic/Numeric Analysis/Synthesis) package has been developed at Caterpillar for excavator linkage design and analysis. The package is written in Mathematica to take full advantage of its computational and graphical capability as well as its powerful notebook front end interface. The package includes several modules for deriving linkage-system equations, supporting users' interactive inputs, conducting analysis and synthesis, and preparing engineering reports. The package, with the notebook front end, is very user-friendly and self-explanatory. It may be used as a tutorial, engineering, marketing, or documentation tool. The application of symbolic analysis results in great progress in the area of engineering computation. It will help engineers explore and understand their system rapidly and comprehensively. This presentation will discuss the general philosophy and approaches of the application as well as the strategies in programming. The SNAS package for the excavator linkage design and analysis will also be demonstrated.