Linkage Synthesis and Optimisation Techniques with Skiboard Product Design Case Study

Abstract

This thesis explores the design development and experimental testing of a planar linkage for the Skiboard, a novel snowsports equipment device. The Skiboard, similar to a skateboard in appearance and style of use, combines two short skis with a bindingless board. Its aim is to fill a gap in the snowsports market for a product that offers a wide range of freestyle and trick riding possibilities, beyond those of a snowboard, while being as stable and easy to ride as a pair of skis. While the concept of the Skiboard in itself is simple, the task of designing a mechanism to link the skis to the board is complex. To translate a gradual lean of the rider into a gradual and equal tilting of the skis requires a multi-loop linkage mechanism. The synthesis and analysis of a mechanism for this application was the inspiration for the development of the synthesis-related design tools presented in this thesis. Design methodologies and design software concepts have been developed for use by designers faced with under-defined, “black-box” linkage synthesis problems similar to the Skiboard mechanism synthesis task. A software-based design of experiments setup, called SMAC, is introduced in this thesis and was used throughout the linkage synthesis process for the Skiboard. One promising candidate mechanism, developed and chosen using SMAC, is followed through to the pre-prototyping phase of the design process. PSEO, another, more advanced, software tool for complex and multi-loop linkage synthesis is also presented in the concept stage of development. This type of program has the potential to automate some of the most time-consuming portions of the synthesis and analysis process with the use of a genetic algorithm and curve-matching algorithm. Additionally, it keeps much of the user’s interaction with the design process and the design itself intact, which is something not offered by existing tools incorporating similar levels of automation. Overall, this thesis is an exploration into the field of linkage design, a topic with little crossover between theory and practical design helps. It includes a review of existing synthesis tools and the development of new tools to suit complex applications such as the Skiboard. The design process for the Skiboard linkage mechanism is also presented and illustrates the way in which the creative design process is iterative, progressively informing the designer’s understanding of the functional requirements of the linkage and how to best satisfy them.