Team Drum Roll Mobile Marching Band Drum Set

Transcription

1 Team Drum Roll Mobile Marching Band Drum Set University of Idaho Mechanical Engineering Senior Design Summer Fall 2011 Aaron Braithwaite Justin Dilworth Sarah Helland Toni Töpfer

2 Executive Summary The following design report details the U.I. Summer Fall 2011 M.E. senior design project to design a mobile drum set. The report is aimed to specifically convey the background of our project, details of the problem faced, the solution paths generated, the actual path taken to arrive at one solution, and the solution described in detail accompanied by a cost estimate, budget summary, and drawing package. Our team, Team Drum Roll, needed to find a way to make a stationary drum set mobile. As the current product market features drums for marchers that sacrifice sound quality for weight and mobility, our task was to design a stationary drum set into a mobile product and hence retain the preferable sound quality while offering required mobility. This project was distributed across two semesters. First semester work consisted largely of concept generation and preliminary prototyping. For simplification the project was divided into four categories: a mobility solution, human interface, drum connection, and frame. The mobility solution was the primary category explored semester one with concepts generated for spherical wheels, omni-directional wheels and lightweight casters. The human interface of the device was decided to consist of a Pearl harness as these are already widely implemented. For the drum connection we decided to use block clamps. Lastly, for the frame we narrowed our considerations to a two or three-legged structure that must be collapsable, lightweight, and hold individual members rigidly together. Second semester we built and tested our prototypes and generated a final design solution accordingly. Interchangeable aluminum components were manufactured in the U.I. Gauss Johnson machine shop. These components were then used to assemble both a two-legged and a three-legged device. Both devices were customer tested and the two-legged frame was accordingly chosen for the final design solution. Additionally, a spherical wheel was developed that rotated and changed direction more easily than the caster wheels. Team Drum Roll Toni Töpfer, Sarah Helland, Justin Dilworth, Aaron Braithwaite 1

3 Table of Contents I. Background!... 3 II. Problem Definition!... 4 III. Concept Exploration!... 5 A. Mobility Solution!... 5 B. Drum Connection!... 6 C. Human Interface!... 6 D. Frame!... 7 IV. Prototype Testing!... 9 V. Detailed Design! A. Mobility Solution! B. Drum Connection! C. Human Interface! D. Frame! VI. Budget Summary! VII. Recommendations! VIII. Appendices! Appendix A: Pearl Catalog Products! Appendix B: Drawing Package for Two-Wheeled Design! Appendix C: Drawing Package for Three-Wheeled Design!

4 I. Background The percussion section of present day marching bands consists of marching drummers with specifically modified marching drum sets (Figure 1) as well as sideline stationary drum stands (Figure 2) for additional instruments. Drums for marching drummers are body mounted and accordingly produced in a light weight fashion that makes them loose the sound quality of drums employed in stationary bands (Figure 3). Stationary sideline drum sets are heavy and large so they cannot be marched with and are difficult to even get out on the field. Daniel Bukvich of the University of Idaho Music Department and Dr. Edwin Odom of the University of Idaho Mechanical Engineering Department have asked us to build a device that allows marching band drummers to play various arrangements of regular drums while marching on the play field. Specifically, we have set out to build a device to support stationary drum sets while enabling the user to be mobile in a marching fashion. The device would provide marching bands with greater freedom of performance movements combined with a larger playable music selection. Figure 1. Figure 2. Figure 3. 3

5 II. Problem Definition The project goal consists of designing a final prototype capable of satisfying below stated constraints during the Summer and Fall 2011 semesters. Final deliverables include this completed project report, a detailed drawing package for the production of future devices and a physical prototype using materials available to us. The final device aims to satisfy the following constraints: Carry at minimum: -One 10 dia. 7 lb. tom -One 12 dia. 8 lb. tom -One 14 dia. 13 lb. snare -One 14 dia. 12 lb. tom -One 18 dia. 4 lb. cymbal Move in all directions on single plane (sideways, forward, backward, turn radially) Enable user to be marching at speeds up to 2 m/s Retain mobility on fields with up to 6 grass growth and level surface Built/adjustable to a wide range of user heights (5 0 to 6 5 for >95% of population) Adjustable to various drumming arrangements User-controlled w/o hands Light-weight, free-standing, stores efficiently Pairs with other devices to form single unit for multiple users To better achieve the above goals our project consists of four primary categories: Mobility Solution- Enables the device to move across the field. Drum Connection- Connects the drums to the device. Human Interface- Connects the user to the device. Frame- Combines all members in a single unit. 4

6 III. Concept Exploration This section describes in detail the four main components of our project: the mobility solution, drum connection, human interface and frame architecture. These developed concepts are based on the initial research conducted during the summer 2011 semester. This research consisted of looking at any and all devices that might relate to the project. Some particularly useful things researched were utility carts, the Pearl drum support system, climbing harnesses, omni-directional wheels and various caster-wheel designs. Products and ideas were evaluated and tested physically when possible. A. Mobility Solution Concept 1: This is an alternative to a regular caster that allows a full range of motion. It uses a miniature caster to allow the spherical ball to rotate in all directions, and the side wheels help with the rotation and also keep it in place. Because the caster is much smaller than the ones we would otherwise use, it rotates much more easily and quickly. Figure 5. Figure 4. Concept 2: This wheel is composed of many smaller wheels set along the outside of a large wheel. The eight smaller wheels are skateboard wheels, held in place with an aluminum central piece. The larger wheel is attached to an axle and rotates in the normal direction of a wheel. The smaller wheel that is touching the ground rotates along its own axle, allowing sideways movement. This eliminates the rotation that makes casters hard to turn. Concept 3: This is a lightweight caster with a large diameter. If a caster is used this is probably the best option. The caster does not have to be manufactured at the school as it is readily available from commercial sellers. Figure 6. 5

7 B. Drum Connection Standard Pearl mounts were chosen (Figure 7), attached with an exterior rack that is built to the standard of the pearl racks (Figure 8). This system is familiar to the drummers who will be using our device and is both secure and compact. Figure 8. Figure 7. C. Human Interface Concept 1: This is the first concept design we considered (Figure 9) and implements a push bar at waist height behind the drums that the drummer would be attached to with a climbing harness type arrangement. This design proved to get in the way of the drummers lower arms and hands, but is nonetheless straightforward to use. Concept 2: The second concept is to bring bars up from below up to the drummer s sides and attach them to the harness there. This would be less in the way of the drummer, but might not give him much advantage when trying to turn the device. Figure 9. Concept 3: This would be to add stomach and back pressure plates with support straps to the above arrangement. This has adjustability issues and is almost certainly less comfortable, but it might prove to be easier to turn with. Figure 10. 6

8 D. Frame Concept 1: Our first experimental prototype was a three-wheeled design (Figure 11) for maximum stability. It had a push bar at the wide side of the triangle. This shape was generally agreed to be effective at carrying the drums, but it was difficult to turn. The enclosed side at the top of the frame got in the way when the drums were played. Figure 11. Concept 2: This is again a three-wheeled design. It melds seamlessly into the drum connection. It has a triangular base that spreads outward to a four sided design at the top. Both the top and bottom sections are left open at the side facing the drummer, so that nothing gets in the way of marching or drum playing. Figure 12. Figure 13. 7

9 Concept 3, Machined Aluminum: Version 1: This is a manufactured version of the basic three-wheel frame. It keeps the external bar set up of the second prototype. This allows for a wide variety of drum arrangements, as the drums can be set up to rest either inside the frame or outside it. Instead of a complex, rigid frame, we stripped it down to the essentials. This may lead to some instability, but allows for much easier manufacturing. The legs are each bent outward, thus allowing extra clearance for the drummer's legs and any large or deep drum that would be carried. Each leg is individually adjustable, as is the attachment for each drum, allowing for not only a wide variety of drum arrangements but for a wide range of drummer heights. A human connection has been added that is a bar bent outward with two holes in it that are compatible with the standard drum harness. Figure 14. Figure 15. Version 2: This is a try for a smaller, more compact version of the frame. Instead of the large external frame it has a horizontal bar in the center of the drums. This is attached to a leg on either end and a bar leading out to the drummer in the back. Because there are only two legs, this frame is not free-standing. It is compatible with the same drum harness as the larger frame and is, of course, lighter. It does not, however, allow for as wide a variety of drum arrangements, as it simply does not have as much bar length. It shares many components with our three-wheeled frame, particularly the drum holders and the legs, which makes manufacture easier. The main advantage of this frame is that it has a much smaller moment of inertia than the larger frame and is therefore going to be easier to turn. 8

10 IV. Prototype Testing This section describes in detail tests carried out during both semesters with respect to the design process. First semester (summer) tests focused on providing feedback from broad concept generation and initial trials, while second semester (fall) tests were based on specific product prototypes built in the machine shop. Semester two tests were carried in conjunction with ME 430, Senior Lab, for detailed statistical analysis. Semester 1 Tests Test 1: For this test, two carts from the U.I. machine shop were rolled across lawn in front of the U.I. Gauss Johnson building. Goals consisted of gaining a better picture of how existing products perform. A heavy shop cart and a lighter and smaller cart were used. Things We Learned: The 4" diameter wheels rolled surprisingly easily across the grass. The heavier and larger cart was much more stable. Clearance at the base of the cart for the drummer s legs is vital. It's hard to start a turn because the cart resists turning. Figure 16. Test 2: We built a first prototype based on what we learned from our test of existing carts and conversations with Dr. Odom and Professor Bukvich at Snapshot Day 1. We used 2x4s and spare casters provided by the music department. We then experimented with pushing the prototype when it was loaded with drums and tried the fit of various harness ideas. The device was shown to Dr. Odom and professor Bukvich for further advice on what should be changed. Things We Learned A highly disproportionate amount of weight ends up on the front wheel. Attaching the drums to a perimeter bar would allow for more flexibility in arrangement. It definitely needs better wheels, because these ones do not move freely and quickly. The push bar has a serious clearance issue with the hands and arms of the drummer. 9

11 Semester 2 Tests Computer Simulation: Computer simulations of each of the frame version's mass and inertia in SolidWorks. The desired arrangement of drums were included in this calculation. Things We Learned: There was only a slight difference in mass between the two frames with the drums. There was a highly significant increase in moment of inertia in the larger frame. We may expect, therefore, that the larger frame will be significantly harder to turn. Figure 17. Movement Testing: For this experiment we had people take each of the drum frames and walk with it. We asked them to march forward for 30 feet, march backward for 30 feet, march left and right 30 feet, turn in a circle, and march out 30 feet, turn around, and march back. We timed them performing these actions and then asked them to rate the performance of the frame for each of them. Our rating system was from one to five, with one being easy to use and five being hard vs. 2 Wheeled Drum Set Rating: 95% Confidence Intervals of Difference of Means Difference of Rating (3-2) forward backward sideways Drum Set Movement circle out and back Figure 19., this shows our difference of means analysis between the two-wheeled Figure 18. Things We Learned: There was no significant difference in the time they took to march the different directions. The two-wheeled frame was significantly easier to turn and move backward with. The shoulder harness bounced off the shoulders when the three-wheeled frame was used. 10

12 Height Testing: For this test, we recorded the height of the drummer and their drum height preference of 10 marching band drummers. We asked the drummer to describe where they wanted the top of the drum to be for their optimal playing height, and we would adjust our frame to fit accordingly. We then used linear regression to find a relationship between the height of the drummer and the frame arrangement preferred by the drummers. Things We Learned: There is a relationship between drummer height and preferred drum height preference. Although the drummer's heights varied by 12" the needed adjustability in the frame was 5". Figure 20., this shows adjusted drum heights for 10 measurements taken from U. I. marching band drummers. 11

13 Along with testing we did this design failure mode and effect analysis. The following criteria was used. DFMEA Criteria Severity 1: No Effect 2: Still functioning and replaceable 3: Not functioning and replaceable 4: Unusable Occurrence 1: Less than once per season 2: Less than once per week 3: Less than once per practice 4: Multiple times per practice 5: Constantly Detection 1: Visible to inspection 2: Detectable by feel 3: Undetectable until failure 12

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15 V. Detailed Design This section describes in detail our final design based on concept generation and prototype testing. Final Mobile Drum Set: To the right is a picture of our implemented prototype. It has all the major features of our final design, but is not quite as polished as the final design will be. We chose this prototype as the base of our final solution over the three-wheeled version for two reasons. First, the harness of this version stayed securely on the shoulders of the user even when traveling over bumpy ground. Second, users rated it as being easier to turn and easier to move backward. Since these are vital abilities for the mobile drum set to have, we decided to go with this frame. Figure 22. Figure 21. A. Mobility Solution Our implemented prototype uses the high quality casters that we scavenged from a walker. These performed adequately during testing but exhibited a marked tendency to resist reversing direction. Our final solution would be, therefore, to use spherical wheels like the one we created a working model of during the last portion of our project. This wheel responds more quickly to a change in direction than a large caster. This is because the large ball can easily rotate in all directions and the small caster included in the wheel does not have to rotate as far to change direction as the stand-alone large caster does. B. Drum Connection We designed these connectors to connect the frame together and also to attach the drums to the frame. The only difference between the connections is that the ones intended for the drums have a triangular groove instead of a rectangular one, in order to better fit the round bar that is attached to the drums. The advantage of these connections is that they make the frame incredibly easy to reconfigure for different arrangements of drums. The main disadvantage of these connections is that they are currently connected by long screws that take a considerable time to loosen and tighten. Additionally, there are better mounts for the drums that we would use in our final design, while retaining these for the frame connections. Figure

16 C. Human Interface Our implemented prototype used an old drum harness that was a solid piece of material that rested on the shoulders of the drummer. This worked well at keeping the drum frame at the right height for the drummer and not getting in the drummers way when moving. It also had the benefit of being a piece of equipment that was readily available. The problem with this harness is that it did not stay close to the body when moving sideways and turning. It also did not provide much leverage when turning. To improve this, our final design incorporates a high-quality drum harness from Pearl like the one on the right. This harness straps securely to the drummers stomach and so eliminates a great deal of the problems we had with the old harness. Figure 24. D. Frame As mentioned above, this frame behaves well when marched with, being relatively easy to turn and move backward. It also stays connected to the drummer well. In addition, the minimalist design allows the drum set to be disassembled into a compact set of bars for transportation purposes. The major change we would make to this frame would be to add a kickstand. As it is, although the frame takes a bunch of the weight off of the drummer, it does not support it fully. This could make it tiring to stand with over long periods of time. Additionally, it makes it a bit difficult to get into and out of. A kickstand would solve this problem. We would also use 1 3/8 square tubing so that we could use the pcx-200 drum brackets sold by Pearl to hold the drums. Total measured weight for the two-wheeled prototype device is 24.2 lb. (without drums). Figure 25. A)single)set)of)components)was)used)to)create)two) prototypes:)one)with)two)wheels)and)one)with)three.) Frame&Connec+on& Human&Interface& Machined)aluminum) blocks)offer)wide) adjustability)and)fast) manufacturing.) Pearl)drummer s)harness)is) easily)available)to)drummers) and)provides)shoulder)as) well)as)waist)support.) Frame& Suggested)final)design)2= wheeled)frame) construc>on)exhibits) preferred)marching) characteris>cs.) Mobility&Solu+on& 3=wheeled)version)of)instrumented)prototype.) Suggested)final)design)spherical) wheel)offers)less)turning) resistance)and)greater)stability) than)present)casters.) 15

17 VI. Budget Summary Provided in this section is a cost breakdown of our entire project as well as an estimated cost of our proposed design. The final cost estimate does not reflect pricing for a spherical wheel as this requires further development and costs are as reflected in the project budget (3D printing). Labor hours are primarily based on initial prototyping times and machine shop work at single device production. 16

18 VII. Recommendations This section details the following recommendations for future product design. Connect Multiple Devices: We would like to come up with an effective solution to allow multiple copies of our device to connect to each other. This would allow the drummers to move in sync for marching configurations and is one of the criteria our client gave us. Our current design can t connect multiple frames together, but could be modified to do so, possibly by adding a connecting bar that attaches to the top of the leg bars. Implement Spherical Wheel: Our final design includes the use of spherical wheels. These are currently not in market and would require many parts to be designed for production. We would need to find a supplier to make 6-8 plastic hollow spheres. Currently they can only be made by machining down solid plastic rounds and end up costing around $300 a sphere. We also need to design an effective cage to house the components. We currently used a 3D printer, but this cost around $500 and it doesn t have the strength necessary to be used for the frame. Ideally our final version would be made of cast components where the cost would be dramatically decreased. Quick Release Connections: A quick release system for our brackets would be great improvement over the button cap screws we were using earlier. Some of the designs that we wish to implement in these brackets would be ether a clamping system used often on bicycles, or a wing nut style clamp that can easily be adjusted without the use of tools. This would require a revision of our brackets that we are currently using in our setup. Pearl Harness: The use of a modern harness with a belt would also increase the mobility of our device. These harnesses are available to market from the Pearl marching band catalog. They would allow the user to have a better connection to our device and therefore make it easier to rotate. Kickstand: To aid in attaching to and removing our device from the drummer we would like to add an easy access kickstand. We would have to design a bracket to hold the kickstand, and design it for easy access. It would also need to be able to be raised and dropped without the drummer needing to use their hands. 17

19 VIII. Appendices Appendix A: Pearl Catalog Products Product: Pearl CX Belt Price: $ Vendor: Product: Pearl PCX 200 Drum Bracket Price: $34.99 Vendor: Drum-Hardware/Drum-Percussion-Stands-Racks/Drum- Percussion-Racks/Rack-Clamps/PCX200-Pipe- Clamp.site7prod product 18

20 Appendix B: Drawing Package for Two-Wheeled Design 19

21 Appendix C: Drawing Package for Three-Wheeled Design 32