Industrial and Manufacturing Engineering Department
BS in Industrial Engineering
Kiteboarding is an ocean sport wherein the participant, also known as a kiter, uses a large inflatable bow shaped kite to plane across the ocean on a surfboard or wakeboard. The rider is connected to his or her kite via a control bar system. This control system allows the kiter to steer the kite and add or remove power from the kite, in order to change direction and increase or decrease speed. This senior project focused on creating a new control bar system to replace a control bar system manufactured by a kiteboarding company, Liquid Force. The current Liquid Force control bar has two main faults, extraneous components and a lack of ergonomic design. Our team aimed to eliminate unneeded components and create a more ergonomic bar. By eliminating components, the bar would also be more cost effective to produce by using less material and requiring less time to manufacture.
We first conducted a literature review into the areas of kiteboarding control systems and handle ergonomics. Based on studies done on optimal grip diameters for reducing forearm stress we concluded that the diameter for the bar grip should be at least a centimeter less than the maximum grip of the user. In addition to the literature review we conducted our own ergonomics surveys on fellow kite surfers regarding their preference towards the shape of the grip. Using ANOVA analysis, we found that riders preferred a bar with a less square center, but no clear preference on an oval shape versus a circular shape, so we decided on circular to minimize manufacturing and material costs. A functional decomposition was then employed on the current bar and a QFD analysis of each component was conducted. We found that 33% of the components composed the plastic bar end swivel. We decided to remove the swivel system due to its lack of use and ergonomics. We then began the design process on the new bar ends and bar center.
We went through two iterations of a smaller square center, choosing a center with chamfered edges to blend with the grip material. Our bar end design went through four iterations ranging from a simple angular boxy look, to a curved design which was more aesthetically and ergonomically pleasing. With SolidWorks models in hand, Mastercam toolpaths were built by our technical advisor, and we machined the bar ends and center out of aluminum billet. For the grip tubing we used carbon fiber tubing. By the end of manufacturing we had three different length bars to test in the ocean and we had reduced the bar part count from 31 parts to 13 parts. To justify the bars we created in terms of cost, we conducted economic comparisons between our bar design and the current bar. We concluded that Liquid Force would save $26,105.87 per year in labor and materials by switching to our bar and using casting processes for manufacturing.
Due to the economic advantage and the new ergonomic design, we feel that Liquid Force should implement the design after further testing and refining. The bar performed without fault in our ocean test session, but we did find that improvements could be made in terms of grip ergonomics; the carbon surface was usable, but an EVA grip would give the user a softer, less slippery surface to steer with. We recommend that more long term testing be done to insure that the glue does not de-bond over time and that the carbon aluminum interface does not corrode. Continuing the project, we will research grip materials such as EVA, and create over molded bar grips and bar end covers.