BandBeesten Robotic Drumset

Return to contents The Band-Beesten is a fully powered drum set created for the University of Idaho Vandal Marching Band. The instrument can be maneuvered and played by a single operator during performances.

Background
The Band-Beesten project was started in 2011 by Dr. Edwin Odom, Professor of Mechanical Engineering, and Dr. Daniel Bukvich, Professor of Percussion and Music Theory. The goal of their collaboration was to create a full drum set that could easily be played and moved by a single person during marching band performances. The 2014-2015 acedemic year is the 4th consecutive year of the project.

2011
Work in the fall of 2011 consisted of researching ideas for a powered platform to assist in parade and marching band performances. The team worked solely on research for a proof of concept and did not build a physical prototype. For more in depth design details refer to the Team Drum Roll webpage.

2012
The design team of 2012-2013 made progress with the BandBeesten's design. Dan Mathewson, a UI graduate student, designed a robotic power driven front ball wheel to enable the machine to receive commands through the operator's body movements. More information on this design can be found in. The 2012 design team made significant progress in designing a human interface and powered movement for the BandBeesten.

2013
In the 2013-2014 academic year, a new team started designing a BandBeesten design that would be light weight and have low friction wheels. This design relied only on man-power and did not have any assisting motors. The team also produced a marketing video for the UI Marching Band using 3D printed models and a stop-motion video design. More information about this design can be found at their page.

Design Specifications

 * Movement and percussion performed by a single operator
 * Have a forward speed of 2.5 mph
 * Have a reverse speed of 2/3 mph
 * Complete a 360 degree rotation in under 2 seconds
 * Able to support ~150 lb
 * Be able to stay charged for a 10 minute performance

Physical Specifications

 * lightweight enough to be lifted by three people
 * Collapsible design for transportation in a vehicle
 * Rigid frame to support a large payload without excessive flexing

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Final Design
With an aluminum frame, the Beest can support more than twice the anticipated payload while weighing less than 250 pounds. To ensure exceptional acceleration with these high payloads, torque is provided by three motors. These motors deliver their power to the ground through an innovative triad of Omni-wheels. To control motion and RC transmitter is used to send signals from a hand-held controller to an Arduino.

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Frame Design
The frame of the BandBeesten was built using aluminum tubing. Aluminum was the material of choice due to its lightweight properties and machinability compared to steel. The total amount of material bought for construction included 80 feet of 1" OD x 0.125” and 12 feet of 3” OD 0.125 tubing to be used in four sections of the frame. These sections are the base, tetrahedron, canopy, and U-bend.

Base
The base section is the most rigid part because the complex stresses acting on it due to the weight of the machine and reaction forces from the ground. In addition to the weight of the BandBeesten, the base section also must withstand torsion from the motors as they maneuver the Beest. To counteract these stresses, The base had to be built using a combination of 3” tubing and 1” tubing. The main section uses 3” tubing to maintain rigidity when reacting to bending stresses due to weight. The concept used here is that the larger a tube’s diameter is, a higher force is needed to bend it. This principle is also used in building telephone poles; the base is much wider than the top to offset wind forces that may otherwise bring it down. If the 3” tubing was used without any other supports, the base still may distort due to the off-center reaction forces at the wheels, these forces would twist the frame causing torsion. To fix this, a sub-frame made from 1” tubing were placed on the inside of the main frame to carry any extra load. A small ¼” aluminum plate was installed to secure the sub-frame. This plate also acts as a cross-brace to connect the two sides of the frame.

Tetrahedron
Triangular shapes are commonly used when building strong structural supports that need to be lightweight. This can be seen in many structural designs ranging from canvas picture frames to bridge trusses. The BandBeesten uses a three dimensional form of this design in the shape of a tetrahedron that has four legs made from 1’ tubing. The tetrahedral shape allows for a stresses on the top of the frame to "flow" straight through the supporting beams without adding harmful bending stresses. Although factors such as the need for space for the operator and a "dashboard" for mounting hardware keep the frame from being a perfect tetrahedron, the basic shape still exists within the frame. The 35” dashboard was made using 1/4” aluminum angle stock and houses the joystick interface box and control switches. The dashboard was made wide enough to support the U-bend that carries the main load of percussion instruments.

U-Bend
The U-bend is the primary mounting location for drums on the BandBeesten. The U-shape allows for endless configurations of instruments to be mounted on the machine instead of individual mounting places for the drums. The bend is made of 1” tubing and connects to the tetrahedron at the front using a support and is supported at the sides by connecting to the dashboard. The rear of the U-bend attaches to the canopy.

Canopy
When performing at large places such as a football stadium, the BandBeesten is dwarfed in comparison to the large venue. To make the Beest look as large as possible without adding excessive weight, the canopy was made. This lets the machine stand over 8 feet high and allows for more places to mount lights, flags, and instruments used during performances. In its current state, the Beest needs the canopy to support the U-Bend, but later modifications could make the canopy optional.

Wheel Design
During operation, the BandBeesten requires movement in all directions and to change directions almost instantaneously. This calls for a unique solution; using three sets of powered Omni-Wheels with an outside diameter of 12”, the BandBeesten is able to maneuver in any direction and change directions in an instant. The wheels can be mounted directly to the frame without any swiveling structures due to the wheel’s unique ability of being able to roll in two dimensions using a large center wheel and small rollers mounted on the perimeter of the center wheel. A complete Omni-Wheel set consists of two offset Omni-wheels to ensure smooth operation of the machine. Each of the six center wheels are designed to have five rollers mounted around their perimeters. Each center wheel is cut from a 12”x .5” square aluminum plate using a CNC mill. The wheel is responsible for rotation on one axis Omni-Wheels are built using two wheels. The larger center wheel rolls on one axis while smaller rollers are mounted around the perimeter. These smaller wheels have a variable radius so that when the large wheel rolls, a constant radius is maintained. To complete an Omni-wheel assembly, two wheels are mounted such that there is never a gap between the wheels that may cause vibrating.

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Frame
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Wheels
The BandBeesten must be able to be moved in any direction on a moment’s notice to keep up with the marching band’s routine. Its wheels must allow maneuvers such as crab walking and rotation as well as straight motion. Designs considered are Omni-ball wheels, conventional casters, and Omni-wheels.

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Project Learning
During the process of building the BandBeesten, we have gathered an extensive amount of information from various resources. Most of what we have learned has to do with the frame, motor controls, and wheel casting.

Frame
The frame will be subject to bending, torsional, and tensile stressses. To design a frame that will withstand these forces while keeping a slim profile, a design was concieved that incorporates a lower frame that is made of 3" tubing that is reinforced by 1" tubing. The tetrahedral portion of the frame has a wide center block with 1" tubes to reduce bending and torsional forces.

Motor Controls
To control the power given to each motor, an arduino is used. The arduino sends a signal to separate motor controllers which in turn sends power to each motor. breakers, fuses, and an emergancy stop button have been installed for safety.

Wheel Casting
In the latest version of the BandBeesten, Omni wheels are being used. 12" wheels are needed to allow for smooth operation, so wheels were manufactured in the UI machine shop due to lack of comercial availability. These wheels will be able to move in any direction without pivoting, but they require a casting process for the sub-wheels if they are to made out of urethane material. The casting process has three parts, setting up the casting molds, mixing the material, and pouring the material.

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Team Members
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