Project

# Title Team Members TA Documents Sponsor
41 Antwieght Battle Bot Project Proposal
 Anthony Shen
Batu Yesilyurt
Praman Rai
 Sanjana Pingali design_document1.pdf
final_paper1.pdf
grading_sheet1.pdf
photo1.jpg
photo2.jpg
presentation1.pdf
proposal1.pdf
video
# Antweight Battlebot

Batu Yesilyurt (batuy2)

Praman (pramanr2)

Anthony (arshen2)

# Problem

Eight teams will compete with their own battlebots in a tournament. The antweight battlebots have the following constraints: Less than 2 lbs, 3D printed plastics, custom PCB that connects via bluetooth to microcontroller, motor or pneumatic fighting tool, and easy manual/automatic shutdown.

# Solution

Our plan is to be able to control and prevent the opposing robot from moving to win by decision. Controlling the opposing robot is an effective yet simple way to earn points. We plan on having arms that extend out and grab the opposing battlebot, preventing it from moving.The biggest challenge that we predict we will face is the 2 lb weight constraint. This might prevent the use of any additional features such as weapons to damage the opposing battlebot when we have it under control.

# Solution Components

## Materials

The primary purpose of our robot will be to control the enemy, this means that our robot needs to be resistant to their attacks. Most battlebots will use kinetic weapons, so we plan on using PETG because of its impact resistance.

## Control System

The controls will be managed and powered by an STM32 microcontroller, which will direct the 3 DC motors (2 drivetrain and 1 weapon) while also utilizing its embedded wireless communication. The bluetooth module will interface with an external controller (likely PC) and will enable low latency wireless control. The microcontroller will also leverage GPIO and PWM to enable precise speed control and directional control for the motors. Furthermore, we will implement an H-bridge for additional control and stabilization.

## Power System

We plan on using a 12v LiPO battery because it would provide us with lots of power for our weapons system while also being light.

## Movement System

We plan on using brushless motors to operate 2 wheels on either side of the battlebot. Our winning condition will involve pushing and controlling the other team's robot so higher torque will be more preferred over high speed motors to be able to move around the other team's battlebot. To save weight we will use a high torque motor with a fixed gear ratio. We will sacrifice speed for torque. We will also try to distribute the weight of the robot components over the wheels to maximize downforce for grip.

## Weapon System

For our weapon, we plan to utilize 2 arms that would wrap around the other robot to control and prevent it from moving. These arms will utilize a big portion of the weight budget in order to make sure they are strong enough to restrain the other robot and also take hits when not deployed.

# Criterion For Success

For a successful project, the robot should complete 3 goals. First is the remote control of the robot through bluetooth or wifi from the PC. Second the robot should automatically disable in the event the remote connection is disabled. Third the robot should drive and operate the weapon to a functional degree

Active Cell Balancing for Solar Vehicle Battery Pack

Tara D'Souza, John Han, Rohan Kamatar

Featured Project

# Problem

Illini Solar Car (ISC) utilizes lithium ion battery packs with 28 series modules of 15 parallel cells each. In order to ensure safe operation, each battery cell must remain in its safe voltage operating range (2.5 - 4.2 V). Currently, all modules charge and discharge simultaneously. If any single module reaches 4.2V while charging, or 2.5V while discharging, the car must stop charging or discharging, respectively. During normal use, it is natural for the modules to become unbalanced. As the pack grows more unbalanced, the capacity of the entire battery pack decreases as it can only charge and discharge to the range of the lowest capacity module. An actively balanced battery box would ensure that we utilize all possible charge during the race, up to 5% more charge based on previous calculations.

# Solution Overview

We will implement active balancing which will redistribute charge in order to fully utilize the capacity of every module. This system will be verified within a test battery box so that it can be incorporated into future solar vehicles.

Solution Components:

- Test Battery Box (Hardware): The test battery box provides an interface to test new battery management circuitry and active balancing.

- Battery Sensors (Hardware): The current battery sensors for ISC do not include hardware necessary for active balancing. The revised PCB will include the active balancing components proposed below while also including voltage and temperature sensing for each cell.

- Active Balancing Circuit (Hardware): The active balancing circuit includes a switching regulator IC, transformers, and the cell voltage monitors.

- BMS Test firmware (Software): The Battery Management System requires new firmware to control and test active balancing.

# Criterion for Success

- Charge can be redistributed from one module to another during discharge and charge, to be demonstrated by collected data of cell voltages over time.

- BMS can control balancing.

- The battery pack should always be kept within safe operating conditions.

- Test battery box provides a safe and usable platform for future tests.