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ESP32 Drone

Multi-Drone Formation

Overview

Section titled “Overview”

Formation flight is an advanced application of multi-drone collaboration. In this project, you will learn how to implement formation flight with 3 drones.

What You’ll Learn

Section titled “What You’ll Learn”
  • Multi-agent systems
  • Cooperative control algorithms
  • Formation control strategies
  • Leader-follower pattern

Materials Needed

Section titled “Materials Needed”
ItemQuantityNotes
3 ESP32-S3 Drones3-
Computer1Python + Pygame installed
formation_simulator.py1Formation simulator

Step 1: Choose a Formation Control Strategy

Section titled “Step 1: Choose a Formation Control Strategy”

The Leader-Follower model is the most commonly used formation control strategy.

Step 2: Open the Project

Section titled “Step 2: Open the Project”

Unzip formation_flight.zip and open it with VS Code.

Step 3: Implement the Leader-Follower Strategy

Section titled “Step 3: Implement the Leader-Follower Strategy”

Open formation.c and implement the follower control:

void follower_control(float leader_x, float leader_y, float leader_z,
                      float offset_x, float offset_y, float offset_z) {
    // 1. Compute desired position: leader_pos + offset
    float desired_x = leader_x + offset_x;
    float desired_y = leader_y + offset_y;
    float desired_z = leader_z + offset_z;


    // 2. Use PID controllers to compute velocity commands
    float vx = pid_controller(&pos_pid_x, desired_x, current_x);
    float vy = pid_controller(&pos_pid_y, desired_y, current_y);
    float vz = pid_controller(&pos_pid_z, desired_z, current_z);


    // 3. Convert velocity commands to motor speeds
    motorsSetRatio(MOTOR_M1, current_ratio + vx - vy + vz);
    motorsSetRatio(MOTOR_M2, current_ratio - vx - vy + vz);
    motorsSetRatio(MOTOR_M3, current_ratio - vx + vy + vz);
    motorsSetRatio(MOTOR_M4, current_ratio + vx + vy + vz);
}

Step 4: Configure Formation Parameters

Section titled “Step 4: Configure Formation Parameters”
  • Leader (Drone 1): position (0, 0, 1)
  • Follower 1 (Drone 2): position (1, 0, 1) (1 meter to the right of the leader)
  • Follower 2 (Drone 3): position (0.5, sqrt(3)/2, 1) (1 meter to the front-left of the leader, forming an equilateral triangle)

Step 5: Testing

Section titled “Step 5: Testing”
  1. Send the “start formation” command from the ground station
  2. Observe whether the 3 drones form and maintain a triangular shape
  3. Challenge: implement “formation switching”, changing from a triangle to a straight line

Troubleshooting

Section titled “Troubleshooting”

Formation not stable

Section titled “Formation not stable”
  • Tune the PID parameters
  • Optimize the communication frequency

Followers fall behind

Section titled “Followers fall behind”
  • Increase the following speed
  • Reduce the formation spacing

Achievement

Section titled “Achievement”

Congratulations! You have implemented multi-drone formation flight — an advanced application of multi-drone collaboration!

Next Steps

Section titled “Next Steps”

In the next project, you will learn how to develop an AI-based visual tracking and recognition system.