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ArduPilot and Pixhawk Quadcopter Development Tutorial

Authors
  • avatar
    Name
    Yinhuan Yuan
    Twitter

Table of Contents

  1. Introduction
  2. Understanding the Basics
  3. Hardware Requirements
  4. Software Setup
  5. Initial Configuration
  6. Calibration Procedures
  7. Flight Modes and Parameters
  8. First Flight Preparation
  9. Advanced Features
  10. Troubleshooting

Introduction

ArduPilot is an open-source autopilot software suite that supports multi-copters, planes, rovers, boats, and submarines. When paired with Pixhawk flight controllers, it provides a powerful platform for developing autonomous quadcopters. This tutorial will guide you through the complete process of building and configuring a quadcopter using ArduPilot and Pixhawk.

Understanding the Basics

What is ArduPilot?

ArduPilot is a comprehensive open-source autopilot software that provides:

  • Stabilization and control algorithms
  • GPS navigation capabilities
  • Autonomous mission planning
  • Telemetry and logging
  • Support for various sensors and peripherals

What is Pixhawk?

Pixhawk is a family of open-hardware flight controllers that run ArduPilot firmware. Key features include:

  • 32-bit ARM processor
  • Built-in sensors (accelerometer, gyroscope, magnetometer, barometer)
  • Multiple I/O ports for peripherals
  • Redundant power inputs
  • SD card for logging

ArduPilot Firmware Variants

  • ArduCopter: For multi-rotors (quadcopters, hexacopters, etc.)
  • ArduPlane: For fixed-wing aircraft
  • ArduRover: For ground vehicles
  • ArduSub: For underwater vehicles

For quadcopter development, we'll focus on ArduCopter.

Hardware Requirements

Essential Components

1. Flight Controller

  • Pixhawk 4: Modern, feature-rich option
  • Pixhawk 2.4.8: Budget-friendly classic
  • Cube Orange: High-end option with built-in vibration isolation

2. Frame

  • Size: 450mm-550mm for beginners
  • Material: Carbon fiber or aluminum
  • X-configuration recommended

3. Motors and ESCs

  • Motors: 920-1000KV for 450mm frames
  • ESCs: 30A minimum, BLHeli_32 recommended
  • Match motor and ESC ratings

4. Propellers

  • 10-12 inch for 450mm frames
  • Carbon fiber or high-quality plastic
  • Always use balanced props

5. Power System

  • Battery: 3S-4S LiPo (11.1V-14.8V), 3000-5000mAh
  • Power Module: Provides power and current/voltage sensing
  • BEC: If not integrated in power module

6. Radio Control System

  • Transmitter: Minimum 6 channels, 8+ recommended
  • Receiver: Compatible with transmitter (PPM, SBUS, or PWM)
  • Popular options: FrSky, FlySky, Spektrum

7. GPS Module

  • M8N or M9N GPS with compass
  • Mount away from magnetic interference
  • Use included mast for elevation

8. Telemetry (Optional but Recommended)

  • 433MHz or 915MHz (check local regulations)
  • Enables wireless parameter tuning and monitoring

Wiring Diagram Overview

Pixhawk Connections:
- MAIN OUT 1-4: Motor ESCs (for quadcopter)
- RC IN: Radio receiver
- GPS: GPS module
- TELEM1: Telemetry radio
- POWER1: Power module
- I2C: External compass (if needed)
- SAFETY: Safety switch
- BUZZER: Buzzer/LED

Software Setup

1. Install Ground Control Software

Mission Planner (Windows)

  1. Download from ardupilot.org
  2. Run installer with administrator privileges
  3. Install drivers when prompted

QGroundControl (Cross-platform)

  1. Download from qgroundcontrol.com
  2. Available for Windows, Mac, Linux, Android, iOS

2. Firmware Installation

Using Mission Planner:

  1. Connect Pixhawk via USB
  2. Select correct COM port
  3. Go to "Setup" → "Install Firmware"
  4. Select quadcopter icon
  5. Follow prompts to install ArduCopter

Using QGroundControl:

  1. Connect Pixhawk
  2. Go to "Vehicle Setup" → "Firmware"
  3. Select "ArduPilot" and "CopterFirmware"
  4. Click "OK" to flash

3. Initial Connection

  • Set baud rate to 115200 for USB
  • 57600 for telemetry radios
  • Verify connection with HUD movement

Initial Configuration

1. Frame Type Selection

Setup → Mandatory Hardware → Frame Type
- Select "X" configuration for quadcopter
- Choose appropriate frame class

2. Radio Calibration

Setup → Mandatory Hardware → Radio Calibration
1. Turn on transmitter
2. Click "Calibrate Radio"
3. Move all sticks and switches to extremes
4. Click "Click when Done"

3. Accelerometer Calibration

Setup → Mandatory Hardware → Accel Calibration
1. Click "Calibrate Accel"
2. Follow prompts for each orientation:
   - Level
   - Left side
   - Right side
   - Nose down
   - Nose up
   - Upside down

4. Compass Calibration

Setup → Mandatory Hardware → Compass
1. Enable compasses
2. Select "Onboard Mag Calibration"
3. Click "Start"
4. Rotate vehicle in all orientations
5. Complete when progress bars fill

5. ESC Calibration

Setup → Optional Hardware → ESC Calibration
1. Remove props for safety
2. Select "All at once" method
3. Follow on-screen instructions
4. Listen for ESC confirmation tones

Calibration Procedures

Motor Test and Direction

Setup → Optional Hardware → Motor Test
1. Remove propellers
2. Test each motor individually
3. Verify correct spin direction:
   - Motors 1&2: Clockwise
   - Motors 3&4: Counter-clockwise
4. Swap any two motor wires to reverse direction

PID Tuning Basics

Initial PIDs are usually adequate, but fine-tuning improves performance:

Config → Extended Tuning
Key parameters:
- Rate Roll/Pitch P: 0.135-0.150
- Rate Roll/Pitch I: 0.135-0.150
- Rate Roll/Pitch D: 0.0036-0.004
- Stabilize Roll/Pitch P: 4.5-5.5

Battery Monitor Setup

Setup → Optional Hardware → Battery Monitor
1. Select monitor type (Power Module)
2. Enter battery capacity
3. Set voltage divider (usually 10.1)
4. Set Amps per volt (usually 17.0)
5. Verify readings match actual values

Flight Modes and Parameters

Essential Flight Modes

1. Stabilize

  • Manual throttle control
  • Self-levels when sticks centered
  • Good for beginners

2. Alt Hold

  • Maintains altitude automatically
  • Easier than stabilize
  • Requires good barometer

3. Loiter

  • GPS position hold
  • Maintains position and altitude
  • Requires good GPS lock

4. RTL (Return to Launch)

  • Autonomous return home
  • Climbs to RTL altitude
  • Lands at home position

5. Auto

  • Follows pre-programmed missions
  • Requires waypoint planning
  • Full autonomous control

Flight Mode Configuration

Config → Flight Modes
- Assign modes to transmitter switches
- Recommended setup:
  - Switch position 1: Stabilize
  - Switch position 2: Alt Hold
  - Switch position 3: Loiter
  - Switch position 4: RTL
  - Switch position 5: Auto
  - Switch position 6: Land

Important Parameters

Safety Parameters

CONFIG → Full Parameter List
- ARMING_CHECK: 1 (all checks)
- FS_THR_ENABLE: 1 (throttle failsafe)
- FS_GCS_ENABLE: 1 (ground station failsafe)
- RTL_ALT: 3000 (30m RTL altitude)
- LAND_SPEED: 50 (cm/s landing speed)

Performance Parameters

- MOT_SPIN_ARM: 0.10 (motor spin when armed)
- MOT_SPIN_MIN: 0.15 (minimum throttle)
- THR_MID: 0.5 (hover throttle estimate)
- PILOT_ACCEL_Z: 250 (vertical acceleration)

First Flight Preparation

Pre-flight Checklist

Hardware Checks

  • Props secured and correct orientation
  • Motors spin freely
  • Battery charged and secured
  • All connections tight
  • GPS has clear sky view
  • Radio link established

Software Checks

  • Correct firmware version
  • All calibrations complete
  • Flight modes configured
  • Failsafes enabled
  • Home position set
  • Parameter backup saved

Arming Procedure

  1. Place quadcopter on level ground
  2. Wait for GPS lock (solid LED)
  3. Ensure throttle at minimum
  4. Hold throttle down-right for 2 seconds
  5. Motors will spin at idle
  6. Check for error messages

First Hover

  1. Start in Stabilize mode
  2. Open area, no wind
  3. Slowly increase throttle
  4. Hover at 2-3 meters
  5. Make small control inputs
  6. Land if any issues

Tuning After First Flight

  • Note any oscillations
  • Check log files for errors
  • Adjust PIDs if needed
  • Verify failsafes work

Advanced Features

Autonomous Missions

Creating Waypoint Missions

Plan → Flight Plan
1. Right-click to add waypoints
2. Set altitude for each point
3. Add commands (takeoff, land, RTL)
4. Write mission to vehicle
5. Verify on map

Mission Commands

  • TAKEOFF: Vertical climb to altitude
  • WAYPOINT: Fly to location
  • LOITER_TIME: Hover for duration
  • LAND: Descend and disarm
  • RTL: Return and land at home

Follow Me Mode

Requires:

  • GPS on ground station
  • Good telemetry link
  • Copter in Guided mode

Precision Landing

Using IR-Lock or companion computer:

  1. Install IR beacon at landing site
  2. Mount IR camera on copter
  3. Configure PLND parameters
  4. Test in controlled environment

Companion Computer Integration

Popular options:

  • Raspberry Pi + MAVLink
  • NVIDIA Jetson for computer vision
  • Intel NUC for advanced processing

Connection via:

  • Serial port (TELEM2)
  • USB
  • Ethernet (some boards)

Troubleshooting

Common Issues and Solutions

Won't Arm

  • Check pre-arm messages
  • Verify GPS lock
  • Calibrate accelerometer
  • Check battery voltage
  • Review ARMING_CHECK parameter

Drifts in Hover

  • Calibrate accelerometer on level surface
  • Check for magnetic interference
  • Verify CG (center of gravity)
  • Trim radio if needed

Toilet Bowl Effect

  • Compass calibration needed
  • Check compass orientation
  • Move GPS/compass away from interference
  • Verify declination settings

Poor Altitude Hold

  • Cover barometer foam
  • Check for prop wash
  • Tune THR_MID parameter
  • Verify MOT_HOVER_LEARN enabled

GPS Issues

  • Ensure clear sky view
  • Check GPS cable
  • Verify GPS configuration
  • Update GPS firmware if needed

Log Analysis

Downloading Logs

DataFlash Logs → Download Logs
- Select log by date/time
- Download .BIN file
- Use for detailed analysis

Key Things to Check

  • Vibration levels (keep below 30m/s²)
  • Power consumption
  • GPS accuracy
  • Desired vs actual attitudes
  • Error messages

Safety Best Practices

  1. Always remove props when testing
  2. Never arm near people
  3. Have a spotter for first flights
  4. Start with small, stable movements
  5. Know your failsafe settings
  6. Keep firmware updated
  7. Maintain your equipment

Resources and Community

Official Documentation

Video Tutorials

  • ArduPilot YouTube Channel
  • Painless360
  • Andrew Newton

Community Support

  • ArduPilot Discord
  • RCGroups ArduPilot section
  • Local drone clubs

Conclusion

Building a quadcopter with ArduPilot and Pixhawk provides an excellent platform for learning about autonomous flight systems. Start with basic configurations, progress gradually, and always prioritize safety. The ArduPilot community is welcoming and helpful for troubleshooting and advancing your skills.

Remember: Success comes from methodical setup, careful testing, and continuous learning. Happy flying!

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