Department of Mechanical and Nuclear Engineering
Modifications to Various Systems for a Rolling Dance Vehicle
A design specification report for a transmission and braking mechanism for a twelve foot dance vehicle, capable of supporting six dancers.
March 15, 2012
Jason KurucIntellectual Property Rights Agreement:No
Steven BatesNon-Disclosure Agreement:No
This design specification report (DSR) by The Penn State Engineering Design Team is an outline for the development and design of a gliding transmission that will be implemented on a large dance vehicle. This dance vehicle will have an inner cage that rotates freely on 12 diameter wheels. The team was tasked with designing a fully functional mechanism that would be completed in 10 weeks (due April 2nd, 2012) within a $1000 budget. The primary needs of the dancers and architects are to minimize noise and friction while ensuring that the vehicle is safe to use.
A roller coaster wheel design was selected to construct the gliding mechanism. The primary design consists of four wheels mounted in a T configuration. There are two in-line wheels on the bottom of to bear the load of the inner cage and dancers. There is one guide wheel on either side of the guide rail to prevent the cage from slipping off of the 12 diameter wheels that they are attached to.
The design team was requested by the sponsor to produce a pre-alpha prototype, allowing them to visually understand the chosen design for the gliding mechanism. Three 2 wide by 3.5 diameter brown phenolic wheels were ordered for this pre-alpha prototype. The team spent one week manufacturing the gliding mechanism, primarily out of plywood and metal shafts. After completion, the sponsor and the architects were better able to grasp the teams proposed concept. During manufacturing, the team discovered that the brown phenolic wheels would not be suitable for the final design due to the low quality of the roller bearings in them. Only the inside of the wheel would spin freely which would cause additional friction between the wheel and the casing.
The next step for the team was to order wheels with stronger bearings that would not cause any friction between the wheel and the casing and could still withstand the loads that will be applied. The team decided to order four 1 wide by 5 diameter performance rubber-tred wheels because they met all the needs that were discovered during the pre-alpha prototype. A new SolidWorks drawing of the casing was generated for the new wheels. This SolidWorks drawing was used to water jet the casing out of 1/16 thick stainless steel sheet metal to manufacture the alpha prototype for testing. In addition to the 1/16 thick stainless steel, the team used 1.5 square steel tubing for additional supports. After completion, the team met with the sponsor and tested the strength of the alpha prototype. The prototype was loaded and rolled down a rail to analyze friction and deflection of the wheels. The wheels and the casing proved to be satisfactory for the final design. The team has recently ordered the steel and additional wheels for the 6 sets of 4 gliding mechanisms.
The total cost of the gliding mechanisms and sheet metal come to $700. The steel used for the framing of the dance vehicle was donated which means there is $300 available to machine components and make small purchases as needed as the project progresses. The budget for this project is $1000 and since the team only has $700 spent, the project is under budget and on schedule thus far.
Table of ContentsExecutive Summary21.0 Introduction41.1 Background41.2 Initial Problem Statement41.3 Objectives52.0 Customer Needs Assessment52.1 Gathering Customer Input52.2 Weighting of Customer Needs63.0 External Search73.1 Patents83.2 Existing Products84.0 Engineering Specifications94.1 Establishing Target Specifications94.2 Relating Specifications to Customer Needs95.0 Concept Generation & Selection105.1 Problem Clarification105.2 Concept Generation115.3 Concept Selection166.0 System Level Design187.0 Special Topics197.1 Preliminary Economic Analyses- Budget and Vendor Purchase Information197.2 Project Management207.4 Ethics Statement218.0 Detailed Design228.0.1. Modifications to Statement of Work22.214.171.124. Introduction126.96.36.199. Customer Needs Assessment188.8.131.52. External Search184.108.40.206. Engineering Specifications220.127.116.11. Concept Generation and Selection18.104.22.168. System Level Design22.214.171.124. Special Topics248.1 Manufacturing Process Plan248.2 Analysis258.3 Material and Material Selection Process268.4 Component and Component Selection Process278.5 CAD Drawings278.6 Test Procedure288.7 Economic Analysis- Budget and Vendor Purchase Information29References29Appendices31Appendix A: Full Customer Needs List31Appendix B: Engineering Parameters33Appendix C: Design Team Budget34Appendix D: Bill of Materials35Appendix E: Gantt Chart37Appendix F: Layout of transmission piece for water jetting38Appendix G: Dimensioned drawings of transmission components39Appendix H: Team Resumes43
A group of Penn State faculty was issued a grant from the Doris Duke Foundation to work with the Diavolo dance company to create a new performance piece. Diavolo Dance Theater is an internationally renowned modern acrobatic dance company (www.diavolo.org). The theme of the project is walking and focuses on the relationship between people, technology, and public spaces. The faculty and students brainstormed and generated an idea for a 12 ft. dance vehicle that would successfully incorporate all of these elements. The idea is that people can walk within the 12 ft. diameter wheels of the dance vehicle to make it transverse terrain, thus connecting people (dancers), technology (the dance vehicle), and public spaces (the terrain upon which the dance vehicle maneuvers). A prototype with a planetary gearing system was built before the engineering design team was presented with the project.
1.2 Initial Problem Statement
The Penn State University engineering design team was presented with a problem concerning the transmission of a large 12 ft. dance vehicle. A design was to be implemented for a gliding/braking mechanism that would allow the inner cage of the dance vehicle to rotate independently from the outer wheels that maneuvered on the terrain. The gearing system of the prototype had to be improved in order for the dance vehicle to operate smoothly and to allow the inner cage to rotate freely. All of this had to be done while minimizing noise and friction that would be created by metal-on-metal contact points. The dance vehicle would not be moving faster than about 5-10mph which influenced the sponsors decision in manufacturing a braking system. The sponsor stated that if time permitted, the design team would create a braking mechanism after the completion of the gliding system. The team has a number of goals to achieve while working under a $1000 budget.
The objective of the project for the design team was to design a gliding mechanism that allowed the inner cage to rotate freely from the outer wheels. This gliding mechanism was to have a braking system that would lock the cage to the wheels; thus the cage would rotate as the wheels rotated. The sponsor noted that manufacturing the braking system was a secondary goal for the team and that completion of that component was not paramount. The architects and the dancers were mainly focused on generating a smooth gliding system. The steel tubing used to construct the dance vehicle did not come out of the Design Teams $1000 budget. The team had sufficient funds to create and manufacture the gliding/braking mechanism. Because the entire budget was allocated entirely towards such a small scope of the design, few limitations were placed on the design. This provided the opportunity for much creative freedom. The team was expected to deliver all aspects of the project on time, as indicated by the sponsor, and with high quality. The design teams main priority was to satisfy most, if not all, of the customer needs listed in section 2.
2.0 Customer Needs Assessment
2.1 Gathering Customer Input
The engineering design team worked closely with the Penn State faculty in architecture, landscape architecture, and dance. The customers for the 12ft. dance vehicle were the three architects (Marcus Shaffer, Alex Bruce, and Kyle Brown) and six selected dance performers that would be using the vehicle in April. The design team worked closely with the architects multiple times each week to specify what issues needed to be resolved. Meetings were held every Friday with both the architects and dancers to discuss what alterations needed to be made to the design and what were the goals for the following week. Detailed records of the customer needs are included in the Appendix A.
The primary needs of the customers were for the design team to redesign and improve the transmission and gearing elements to allow the inner cage to spin freely from the outer two wheels while reducing friction and noise. It is important to address that the design team decided that safety is paramount in this particular project. Heavy materials were used and dancers were performing in the vehicle while it is in motion.
2.2 Weighting of Customer Needs
By gathering the customer needs, the team was then able to assess each one. Weighting of these needs was vital to the project because the team could clearly identify what main requirements would be needed in the vehicle. Weighting the customer needs also enabled the team to prioritize what aspects of the vehicle to work on to ensure the highest