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Overview

This page guides you through assembling your Mecanum robot, from 3D printing parts to final integration of all subsystems.

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Pre-Assembly Checklist

Before you start assembly, ensure you have:
  • All 3D printed parts (cleaned and tested)
  • All purchased components (motors, wheels, electronics)
  • Complete fastener set (M3 screws, nuts, standoffs)
  • Tools (hex keys, screwdrivers, pliers, wire strippers)
  • Wiring diagram handy
  • Multimeter for electrical testing

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3D Printing Tips

Remember: Maximum 2 prints per group! Print smart.

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Pre-Print Verification

  1. Check Models:
    • All STL files error-free
    • Holes correct size (3.2mm for M3 tapping)
    • No impossible overhangs
  2. Slicer Settings: 
    Material: PLA (easy) or PETG (stronger)
Layer: 0.2mm
Infill: 25% gyroid
Walls: 3 perimeters
Supports: Minimize (design for printability)
Brim: 5mm for bed adhesion
  3. Print Orientation:
    • Strongest along layer lines
    • Minimize supports
    • Flat surfaces on bed

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Post-Printing

  • Remove supports carefully
  • Clean holes with 3mm drill bit
  • Tap M3 threads or use heat-set inserts
  • Test fit before final assembly

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Assembly Sequence

1

Step 1: Prepare Base Plate

  • Clean 3D print or cut material
  • Install standoffs for electronics
  • Mark motor positions
2

Step 2: Mount Motor Brackets

  • Attach 4× motor mounting brackets
  • Use M3×10mm screws + nuts
  • Ensure brackets perpendicular to base
  • Check alignment with level
3

Step 3: Install Motors

  • Mount motors to brackets (4× M3 screws each)
  • Route encoder wires through chassis
  • Verify shafts parallel and level
  • Critical: Check shaft alignment!
4

Step 4: Attach Wheels

  • Install set-screw hubs or couplers
  • Slide wheels onto shafts
  • Tighten set screws
  • Verify wheels rotate freely
  • Check: Left/right rollers correct orientation
5

Step 5: Mount Electronics - ESP32

  • Install on standoffs (M2.5 or M3)
  • USB port accessible for programming
  • Secure with screws
6

Step 6: Mount Motor Drivers

  • Install 4× IBT-2 drivers
  • Allow airflow (don’t seal)
  • Position for short motor wires
  • Secure with screws or adhesive
7

Step 7: Mount Raspberry Pi

  • Standard mounting (4× M2.5 screws)
  • All ports accessible
  • microSD card reachable
  • Add heatsink if available
8

Step 8: Mount IMU

  • Center of robot (best for measurement)
  • Rigid mount (no flex)
  • Flat and level
  • Note orientation (X-forward, Z-up)
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Step 9: LiDAR Mount

  • Top-mounted, elevated
  • 360° clear view
  • Stable (no wobble)
  • Height: 100-150mm above ground
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Step 10: Power Distribution

  • Install terminal blocks or bus
  • Mount buck converter
  • Add fuse holders
  • Battery mounting area prepared
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Step 11: Wiring - Power

Follow wiring diagram exactly!
  • Battery → main switch → fuse
  • 12V to motor drivers
  • Buck converter 12V→5V
  • 5V to ESP32, RPi, sensors
12

Step 12: Wiring - Motors

  • Motor power to drivers (thick wire)
  • PWM signals ESP32→drivers
  • Keep wires neat with zip ties
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Step 13: Wiring - Encoders

  • Connect encoder A/B to ESP32
  • +5V and GND for encoder power
  • Secure wires (prevent snagging)
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Step 14: Wiring - Sensors

  • IMU I2C to ESP32 (SDA, SCL)
  • LiDAR USB to Raspberry Pi
  • Camera ribbon cable (if used)
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Step 15: Cable Management

  • Zip ties for wire bundles
  • Keep cables away from wheels
  • Label wires (masking tape + marker)
  • Strain relief at connectors
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Step 16: Battery Installation

  • Secure with velcro straps
  • Easy access for removal
  • Low position (stability)
  • LiPo safety bag recommended
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Step 17: Pre-Power Checks

Critical before powering on!
  • Visual inspection: No loose wires
  • Multimeter: Check voltages, no shorts
  • Verify all connections to diagram
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Step 18: Initial Power-On

  • Connect battery (main switch OFF)
  • Turn on switch
  • Check voltages: 12V and 5V rails
  • Listen for unusual sounds
  • Feel for hot components
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Step 19: Software Upload

  • ESP32: Upload test code via USB
  • Raspberry Pi: Boot and configure
  • Test GPIO outputs (blink LED)
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Step 20: Motor Test

  • Test one motor at a time
  • Low speed first (20% PWM)
  • Check rotation direction
  • Verify encoder readings
  • Stop immediately if problems

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Critical Alignment: Mecanum Wheels

Most Common Mistake: Incorrect wheel orientation!

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Correct Wheel Configuration

Top View (looking down):

    Front
  ┌───────┐
  │ \   / │   Rollers form "X" pattern
  │  \ /  │   viewed from top
  │  / \  │
  │ /   \ │
  └───────┘
    Rear

Front-Left:  Rollers ↘ (down-right)
Front-Right: Rollers ↙ (down-left)
Rear-Left:   Rollers ↗ (up-right)
Rear-Right:  Rollers ↖ (up-left)
Test: All wheels same speed → robot goes forward (not sideways!)

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Tools Required

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Hand Tools

  • Hex key set (M2, M2.5, M3)
  • Screwdriver set (Phillips, flathead)
  • Pliers (needle-nose, regular)
  • Wire strippers
  • Wire cutters
  • Drill with bits (if tapping holes)
  • Tap set (M2, M2.5, M3) - optional
  • Soldering iron + solder
  • Hot glue gun (optional, wire management)

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Measurement Tools

  • Digital calipers
  • Ruler/tape measure
  • Multimeter (essential!)
  • Level (smartphone app works)

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Safety Equipment

  • Safety glasses (drilling, cutting)
  • Anti-static wrist strap (electronics)
  • Heat-resistant mat (soldering)

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Common Assembly Issues

Causes:
  • Motor shaft not perpendicular
  • Loose set screws
  • Bent shaft or wheel
Fix:
  • Re-mount motor bracket (check with level)
  • Tighten set screws firmly
  • Replace damaged parts
Causes:
  • Rubbing on chassis
  • Over-tightened wheel hub
  • Debris in rollers
Fix:
  • Increase clearance (sand chassis edge)
  • Loosen hub slightly
  • Clean rollers
Causes:
  • Wrong polarity
  • Bare wire touching metal
  • Damaged component
Fix:
  • STOP! Disconnect power immediately
  • Use multimeter to find short
  • Insulate all connections
  • Double-check wiring diagram
Causes:
  • Loose connection
  • Blown fuse
  • Incorrect wiring
Fix:
  • Check continuity with multimeter
  • Test fuses
  • Trace connections to source

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Testing Checklist

After assembly, systematically test:
  • Power rails: 12V and 5V present
  • ESP32 powers on (LED indicator)
  • Raspberry Pi boots
  • Each motor spins (test individually)
  • Encoder signals read correctly
  • IMU communicates (I2C scan)
  • LiDAR spins and publishes data
  • No excessive heat from components
  • All wheels rotate freely by hand
  • No loose wires or parts

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Weight Distribution

For best performance:
  • Battery Low: Improves stability, lowers center of gravity
  • Heavy Components Centered: Balance prevents tipping
  • Symmetric: Even weight distribution left/right, front/back
  • Target Weight: 2-4 kg total (lighter = less motor load)

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Troubleshooting Guide

SymptomLikely CauseSolution
Robot drifts in one directionWheel misalignment, uneven motor speedsCheck wheel orientation, calibrate PID
Motors stutterLow voltage, loose encoder wiresCheck battery charge, secure connections
One motor not workingWiring error, bad driverTest motor directly, check driver connections
ESP32 won’t programUSB driver, wrong COM portInstall drivers, check Device Manager
IMU not respondingI2C wiring, address conflictCheck SDA/SCL, scan I2C bus
LiDAR no dataUSB power, driver issueCheck USB cable, install rplidar_ros

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Maintenance Tips

Weekly:
  • Check all screws (vibration loosens them)
  • Inspect wires for wear
  • Clean wheel rollers
  • Verify battery voltage
Monthly:
  • Re-tighten set screws
  • Check motor brush wear
  • Update firmware if needed

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Documentation

Take photos during assembly:
  • Before/after each major step
  • Close-ups of connections
  • Label everything clearly
  • Create assembly video (useful for presentation!)

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Next Steps

WP3: ESP32 Programming

Program the embedded system

WP3: Motor Control

Implement PID control

WP4: ROS2 Setup

Set up ROS2 for autonomous navigation

Troubleshooting

Solutions to common problems