Obstacle Avoidance Expert

Overview

Real-time obstacle avoidance is the key guarantee for safe drone flight. In this project, you will learn how to develop real-time obstacle avoidance systems.

What You’ll Learn

• Obstacle avoidance algorithm principles
• Artificial Potential Field method
• Vector Field Histogram (VFH)
• Dynamic Window Approach (DWA)

Materials Needed

Item	Quantity	Notes
Drone with Distance Sensors	1	VL53L0X, TOF sensors
Computer	1	With VS Code + ESP-IDF environment
USB Cable	1	For programming
Indoor Environment	1	With obstacles placed

Step 1: Understand Obstacle Avoidance Systems

Obstacle avoidance systems detect surrounding obstacles through sensors, plan safe paths and control drones to avoid obstacles.

Common obstacle avoidance algorithms:

• Artificial Potential Field method
• Vector Field Histogram (VFH)
• Dynamic Window Approach (DWA)

Step 2: Sensor Layout

Install multiple distance sensors around the drone (front, back, left, right) for all-direction obstacle detection.

Step 3: Obstacle Avoidance Algorithm Implementation

Select DWA (Dynamic Window Approach):

void obstacleAvoidance() {
    // Read sensor data, detect obstacles
    float dist_front = readDistanceSensor(FRONT);
    float dist_left = readDistanceSensor(LEFT);
    float dist_right = readDistanceSensor(RIGHT);

    // Build obstacle list
    Obstacle obstacle_list[10];
    int obs_count = 0;

    if (dist_front < 200) {
        obstacle_list[obs_count].x = current_x + dist_front;
        obstacle_list[obs_count].y = current_y;
        obs_count++;
    }

    // Use DWA algorithm to plan safe velocity
    float vx, vy, vz, yaw_rate;
    dwaPlanner(&vx, &vy, &vz, &yaw_rate, obstacle_list, obs_count);

    // Control drone to execute avoidance action
    commanderSetVelocitySetpoint(vx, vy, vz, yaw_rate);
}

Step 4: Compile, Flash and Test

1. Compile and flash the code
2. Test in indoor environment with obstacles placed

Troubleshooting

Slow obstacle avoidance response

• Optimize sensor reading frequency
• Simplify obstacle avoidance algorithm

Unreasonable avoidance path

• Adjust DWA parameters
• Increase number of sensors

Achievement

Congratulations! You have implemented real-time obstacle avoidance system, which is an important guarantee for safe drone flight!

Next Steps

In the next project, you will learn how to use OpenCV library for real-time color target tracking.