Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 11 | Ant-weight Durian Battlebot |
Matthew Jin Timothy Fong Ved Tiwari |
Zhuoer Zhang | design_document1.pdf proposal1.docx |
|
| # Title Ant-Weight Durian Battlebot # TEAM MEMBERS: - Matthew Jin (mj41) - Tim Fong (tfong5) - Ved Tiwari ( vedt2) # PROBLEM Want to design an Ant-weight Battlebot that can outlast and tactically out-compete other entries into the competition. Several restrictions/requisites (outlined by the National Robotics Challenge rulebook) are as follows: - Robot must be under 2lb (we are not opting for a bipedal/quadpedal robot) - Usage of an H-bridge motor system - No metal components whatsoever - Weaponry (either passive or active) - Power delivery system (battery) - Usage of sensors/actuators - Must be 3D printed using one/multiple of 5 materials: PET, PETG, ABS, PLA, PLA+ - Custom PCB to house a microcontroller - Microcontroller must have bluetooth or wifi capability to be controlled externally via a nearby PC/laptop - Simple and complete manual shutdown (within 60s) without the usage of an RF link # SOLUTION Collaboratively decided on a Battlebot design with a passive/counter-type weapon, being spikes that cover the outer shell (resembles a Durian shell with rounded, shallower spikes). Numerous other countermeasures and engineering decisions have been culminated to account for tactics employed by other participating teams. Unlike other common approaches, the absence of an active weapon allows for weight to contribute toward other directions. With this passive weaponry, it falls down more toward microcontroller-initiated, driver assistance algorithms and the shell armor design to disarm/decommission the competition. You’re in trouble. # SOLUTION COMPONENTS ## PASSIVE WEAPONRY The shell spikes are intentionally shallow and rounded to prevent chipping, and to maximize structural integrity under impact. This will prove useful against many active weapon forms, namely the hammer and rotary-type Battlebots in head-on collisions. ## OUTER SHELL Due to the absence of an active weapon, this gives more wiggle room to make the outer shell thicker. To counter Battlebots with forklift/door wedge armaments that aim to flip us over, we will intentionally minimize the clearance room between the bottom lip of the shell and the bottom of the wheels. Additionally, the shell will be thicker toward the middle/base (compared to the top) to create an even lower center of gravity. This shell will be 3D printed using the PETG material, given its functional robustness in the context of this Battlebot competition. It is durable, impact resistant, non-brittle, and warp-resistant during the printing process. ## ELECTRONICS Preface: To include details regarding sensors, battery system, the microcontroller, AND the electronics + battery trays. We decided to use an STM32 microcontroller compared to other popular microcontrollers (namely ESP32) due to its superior compute power. The STM32 provides us with a better ability to perform algorithmic computations on board from data collected from our sensors. An example use case of this might be to determine if and when the bot is close to flipping over. By calculating the y offset from the gyroscope and accelerometer on the IMU, we can send a signal to the wheels to spin it at a certain frequency to reduce the chances of flipping. Apart from this, the STM32 provides us with native Bluetooth and WIFI support out of the box, eliminating the need to configure separate chips to the microcontroller setup. For the battery, we have chosen the 4S (14.8V) 750mAh LiPo battery, as it provides ample flexibility between power and charge capacity: both of which are important for a nimble Battlebot that can last the entire contest. This battery will be stored in a lower-level tray (to again, lower the center of gravity) to protect it. Additionally, a battery-health specialized transistor chip will be utilized. There will be a buck converter that will step down the 14.8v in order to power the microcontroller and other components at the correct voltages that require less voltage. We are to use IMU and load sensors for the sake of creating 2 feedback systems. The first feedback system is between the microcontroller and the Battlebot’s localization. The second feedback system is between the microcontroller and the motor health/status. The goal of initializing these two systems is for the sake of ensuring the Battlebot’s movement is both accurate, and that its motors do not malfunction. Alongside the sensors, the microcontroller/PCB will be located in an upper-level tray above the battery tray. ## DRIVETRAIN As outlined in Professor Gruev’s slides, we are to use an H-bridge system. We’ve opted for a multidirectional 4WD setup with the wheels being attached to the inner perimeter of the shell. With this approach, fluid motion exists while simultaneously shielding the wheels from external impacts. Wheels will be made of urethane, as they are heavy (contribute toward lowering the center of gravity), durable, have good grip, and less wear factor. Brushless DC motors will be used due to their incredibly high power-to-weight ratio and long lifespan (reliable). # CRITERION FOR SUCCESS - Battlebot electronics are well-protected, functional, and durable - Outer shell does not break under expected impact - Spikes do not chip and prove effective in using others’ active weapons against them - Battlebot does not flip over during trial runs/competition scenario reenactments - Battery lasts the entire combat duration |
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