Marching Band Mobile Platform (The Bandmobile)

The Vandal Marching band is well-known for their rousing halftime shows that bolster school spirit and provide memorable entertainment at sporting events as well as other activities. This project continues a multi-year collaboration with the College of Engineering in creating awe-inspiring technological platforms and innovations that add an extra level of intrigue to their performances. This year’s updates include four independent omni-wheels with next-generation lithium battery energy storage and robust power electronics/controls. The final platform should be easily reconfigurable for multiple instrument and lighting set-ups.

=Problem Definition=

Background
Previous iterations of this project include the following:

Deliverables & Specifications
=Final Design=

=Subsystems=

Drivetrain
Overview The drivetrain system connects the wheel subassembly to the frame and allows the platform to move.

Deliverables The drivetrain subsystem must allow movement to the wheels which moves the platform in a safe manner. It must also be properly secured to the frame to allow said movement.

Requirements
 * Reduction ratio of 8.3:1 for the gear motor subassembly

Development We adopted parts from the previous year’s team. These parts included the wheel subassembly and gear motors. Thr drivetrain subsystem has not changed since last year’s team had it, but we did have to change things to fit our new platform design. Bearing blocks needed to be remanufactured to fit the new platform and gear motor mounts were manufactured to fasten the motor to the gusset plates of the frame.

Current Status The assembly has been completed and was delivered to the ECE team for circuit testing.

Validation Completed tests: Planned tests:
 * Motor operates properly with minimal noise
 * Wheels are able to move freely within the assembly
 * Couplers are allowing clear signal from motor to encoder
 * Performing a 360 degree turn in place
 * Operating under load for 10 minutes

Additional Photos

Lighting
Overview The lighting subsystem involves LEDs which can be mounted to the platform frame or to instruments in a variety of ways, in order to draw attention to the entire platform during shows. It also involves a microcontroller that will be controlling the LEDs and will be remote-operable.

Deliverables The Marching Band will have an easy-to-use, flexible lighting system, with multiple hardware and layout alternatives. Limited technical skills should be required to operate, troubleshoot, or adjust the system. This lighting will make the platform visible at any point in the Kibbie Dome, will be remote-controlled, and will be operable for the duration of the Marching Band’s performances.

Requirements
 * Microcontroller: ATmega32u4 (8MHz, 3.3V)
 * Development board: Adafruit Feather
 * LEDs: Adafruit RGB NeoPixel (2A per meter/60mA per LED, 5V)

Development

Current Status

Validation

Additional Photos

Frame
Overview The frame serves as the platform’s light and strong skeleton. It is also where the platform decking is mounted. The longest member of the frame serves as a torsional bar allowing the frame to flex, permitting all wheels to contact the ground. The wheel assemblies are mounted to the frame using gusset plates as well.

Deliverables

Requirements

Development

Current Status

Validation

Additional Photos

Battery Box
Overview

Deliverables

Requirements

Development

Current Status

Validation

Additional Photos

Overview & Requirements



The battery box is the containment device for the power of the platform. It holds each battery cell in place, so they are not knocked around and damaged. It also ensures that all the batteries are in contact with one another, which will create a steady voltage and battery stress across all cells. The whole box must be functional as well as aesthetic as it will be on the deck and visible.

The battery directly interacts with the Battery Monitoring System (BMS), but it also influences the entire platform's functionality. The battery is controlled by the BMS, and power runs to the motor controller and motor; at the same time, the battery provides power for the BMS and micro-controller. Physically the battery box is located on the top of the platform.

Development

We were planning to use completely new batteries--selected by the Spring-Fall electrical team--so the containment device had to be completely different as well. We were originally going to be spot welding all the batteries which would make a nice compact block (Version 1, below).

This idea was thrown out the window when the team building the battery realized that the spot welder that they bought could not actually spot weld the material being used. This called for a compression fit, which is considered inferior. Thus, in the second iteration, we created individual cylindrical tubes that attached each group of cells in parallel to account for the Amp-hours (Ah) needed. Then each cylindrical block would be connected in series to get to the desired voltage. Prototypes were made (Versions 2-4), but during the finalization process we realized it was much too big and expensive to continue.

This led to yet another iteration which is not yet complete. We will be looking into an option using a 3-inch tube and figuring out how get constant pressure on each battery.

=Team Members=

=Documentation=

Project Schedule
Please find our live Gantt Chart here.

Design Validation
Please find our live Validation Plan here.

Budget
Please find our live Budget here.

Minutes
Please find our meeting minutes (updated 8 December 2020) below:

Presentations
Design Review 1 (10-11-2020 08:30)

Snapshot 1 (13-10-2020 15:30)

Snapshot 2 (04-12-2020 08:30)