Project

# Title Team Members TA Documents Sponsor
24 4WD Wedge + Powered Roller Antweight Battlebot
Junyan Bai
Yuxuan Guo
Zhuoer Zhang
# 4WD Wedge + Powered Roller Antweight Battlebot

Team Members:
- Yuxuan Guo (yuxuang7)
- Junyan Bai (junyanb2)

# Problem

Antweight (≤ 2 lb) combat robots must remain mobile and controllable while enduring impacts, motor stalls, and power transients. Many teams lose matches due to loss of traction, getting stuck on opponents/walls, or electronics brownouts and wireless dropouts that lead to uncontrollable behavior or resets. Therefore we want a competitive design that emphasizes reliable control and survivability: a low wedge to get under opponents and a powered front roller to help pin/deflect opponents and prevent getting stuck, while using a custom PCB that integrates wireless control, motor driving, and safety shutoffs.

# Solution

We will build a 2-lb antweight combat robot featuring:
- A low-profile front wedge for ground control and deflection
- A powered front roller mounted above the wedge lip to assist in pinning, lifting slightly, and guiding opponents
- Four-wheel drive (4WD) for pushing power and maneuverability
- A custom control PCB centered on an ESP32 to provide PC-based wireless control (WiFi/Bluetooth), motor control, and robust safety mechanisms

The system is divided into four main subsystems: (1) Power & Safety, (2) Control & Communication, (3) Drive Train, and (4) Roller Mechanism. The design prioritizes predictable behavior under stalls/impacts and includes automatic shutdown on wireless link loss.

# Solution Components

## Subsystem 1 — Power & Safety (Power Management and Distribution)

**Function:** Deliver stable power to drive and roller systems while protecting logic electronics from brownouts and ensuring safe shutdown.

**Safety features:**
- Manual hard shutdown via kill switch
- Firmware-controlled motor disable line(s)
- Brownout monitoring (ADC measurement of battery/logic rail)

## Subsystem 2 — Control & Communication

**Function:** Receive operator commands from a PC, process safety logic, and output PWM/enable signals for motor drivers.

**Components:**
- Microcontroller + wireless: Espressif ESP32-WROOM-32D (WiFi/Bluetooth)
- Status indicators: LEDs for power/armed/link state (part numbers TBD)
- Optional orientation sensing (stretch): MPU-6050 IMU module (GY-521) for flip detection and drive remapping

**Firmware logic:**
- Drive mixing (arcade/tank) for 4WD control
- Roller speed control
- Link-loss failsafe: if command packets stop for > X ms, disable all motors
- Input shaping (rate limiting / exponential curve) for controllable driving

## Subsystem 3 — Drive Train (4WD Locomotion)

**Function:** Provide reliable mobility and pushing power during combat.

**Components:**
- 4x Drive motors

**Mechanical:**
- Four wheels mounted to a 3D-printed chassis
- Wheel size chosen to improve traction and reduce high-centering (exact diameter TBD)

## Subsystem 4 — Powered Front Roller (Control Weapon)

**Function:** Improve control by pinning/deflecting opponents and reducing the chance of getting stuck on wedges or walls.

**Components (with part numbers):**
- Roller motor: small brushed DC motor (e.g., N20/130-size class), final selection TBD
- Roller driver: shared motor driver family with drive train
- Roller structure: 3D-printed roller with compliant sleeve (TPU) or textured surface for grip (material TBD)

# Criterion For Success

The project will be considered successful if all criteria below are met:

1. **Weight compliance:** Total robot mass (including battery) is **< 2.0 lb**.
2. **Manual shutdown:** Manual kill switch stops all motion within **≤ 2 seconds**.
3. **Failsafe shutdown:** On wireless link loss (no valid commands for a defined timeout), all motors are disabled within **≤ 2 seconds**.
4. **Mobility reliability:** Robot can drive continuously for **≥ 3 minutes** without MCU resets or power brownouts.
5. **Control effectiveness:** Robot can push a standardized test object (defined weight) across **1 meter** on the arena surface without stalling into a reboot.
6. **Roller reliability:** Roller can run continuously for **≥ 60 seconds** without causing logic rail brownout or driver overheat shutdown.
7. **Impact robustness:** After **10 wall-impact tests** (full-speed bump into a rigid barrier), the robot remains operational with no loose power connections and no repeated resets.

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