Robotic Fence Building System

Introduction

This document outlines the development of a robotic fence-building machine designed to automate the construction of wooden fences, significantly reducing labor costs. The system is based on a modular, rail-guided robotic train capable of terrain mapping, post hole drilling, post installation, rail attachment, picket placement, and final hardware installation.

Table of Contents

• URS
• Physics
• Free Body Diagram
• Design
• BOM
• Electronics
• Code
• Modeling
• Fabrication
• Guides
• Notes
• Contact

URS

User Requirement Specifications

Requirement	Constraint	Goal
Automation	Full fence build	Minimal human interaction ✅
GPS Accuracy	Sub-inch precision	Use RTK-GPS or visual SLAM
Power Supply	Rechargeable, autonomous	Solar + LiFePO4 battery banks
Rail System	Portable, terrain-adaptive	12″ wide modular track
Safety	Avoid underground hazards	GPS, ultrasonic, GPR integration
Compatibility	Standard lumber sizes	4×4 posts, 2×4 rails, standard pickets
Build Speed	Efficient construction	Target: 30 ft/hr

Physics

• Forces: Torque during drilling, soil resistance
• Post Stability: Cement curing, vibration requirements
• Motion: Robotic arm payload vs. reach balance

Free Body Diagram

[Insert sketch showing robot on rail with drilling arm, forces, moments, and center of mass]

Design

• Track System: 12” wide modular aluminum or composite rail
• Chassis: Self-leveling, dual-motor bogie
• Navigation: RTK-GPS, visual SLAM, ultrasonic rangefinding
• Modules:
  • Survey Module: Maps GPS and detects obstacles
  • Drill Module: Auger with adaptive feedback
  • Post Module: Auto-leveling, cement dispensing
  • Rail Module: Laser-guided triple-rail placement
  • Picket Module: Auto-loader with screwgun
  • Hardware Module: Installs latches and hinges

BOM

Component	Qty	Description
RTK-GPS module	1	Sub-inch GPS accuracy
LIDAR/Ultrasonic sensors	4	Obstacle detection
Servo motors	10+	For multi-axis robotic arms
Auger drill	1	Post hole creation
Cement hopper + pump	1	Automatic cement dispensing
Linear actuators	Many	Leveling and precise movements
MCU (ESP32/Jetson Nano)	1	Centralized control unit
Solar panel (optional)	1	Recharge idle battery system

Electronics

• Distributed microcontroller network
• Sensor fusion (IMU + GPS + Visual)
• CAN bus or LoRa communication
• Battery management system (LiFePO4)

Code

• Written in C++/Python
• Modules:
  • Survey and mapping
  • Pathfinding and control
  • Drill and cement control
  • Arm kinematics and PID tuning
  • UI/UX dashboard for operator

Modeling

• CAD: Chassis, rail connectors, robot arms
• FEA: Force distribution under load
• Simulation: Rail travel, fence layout coverage

Fabrication

• CNC for chassis and mounts
• 3D printing for brackets and arm joints
• Bolt-together track with snap-fit joiners
• Modular assembly jig

Guides

• Setup: Track layout, calibration, diagnostics
• Safety: Emergency stops, sensor pre-checks
• Maintenance: Cleaning cement lines, joint lube, firmware update

Notes

• Consider splitting bots: one for drilling/posts, another for rails/pickets
• AR visualization tool for user pre-layout
• Future AI optimization for jagged or irregular terrain