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Simulation of Martian Arena in Webots for Autonomous Drone Testing

Introduction

To develop and evaluate autonomous drone navigation algorithms in a Mars-like environment, we replicated a Martian surface arena within the Webots simulation platform. This virtual testbed enables rigorous testing and refinement before deployment on physical hardware.

Arena Setup

The simulated environment replicates the example arena provided in competition resources:

  • Gravity: Set to Mars gravity (3.73 m/s²)

  • Surface: Rugged Martian-like terrain with uneven textures and multiple rock obstacles

  • Arena Dimensions: Scaled according to rulebook specifications

  • Drone Control:

    • Manual control implemented using teleoperation (teleop) mode
    • All recorded demonstrations showcase the drone in autonomous mode for clarity and smooth operation

Manual Controls

  • W – Ascend
  • S – Descend
  • Q – Rotate counter-clockwise
  • E – Rotate clockwise
  • Arrow Keys – Move in respective directions at current altitude

Motor Tuning

All motor PID controllers were tuned specifically for Martian gravity conditions, ensuring stable and responsive flight dynamics.

Demonstration Videos

STABLE VERTICAL TAKEOFF

This demonstration shows a stable vertical takeoff.

  • Target altitude: 4 meters
  • Stabilized altitude: 4.01 meters

The drone maintains accurate altitude hold under simulated Martian gravity, validating PID tuning performance.

SAFE SPOT DETECTION

Objective

Detect and identify flat landing zones.

  • Home position: 1.2 m × 1.2 m (4 ft × 4 ft)
  • Additional safe spots: Three 1.5 m × 1.5 m flat zones

Detection Logic

  • Onboard camera scans terrain
  • Flat areas (< 15° slope) marked as safe
  • Drone shifts laterally in 90° increments after detection
  • Coordinates logged to console

Visual Aids

  • Red Box: Potential safe spot (RGB view)
  • Green Dot: Optimal landing point (grayscale view)

Display outputs include:

  • RGB camera feed
  • Grayscale feed (topography-focused, color-neutral analysis)

Safe spot counter updates dynamically from 1 to 4.

STEREO DEPTH ESTIMATION

Configuration

  • Stereo camera setup modeled after Intel RealSense D435i
  • Monocular cameras used in other tests for performance efficiency
  • Stereo used here for improved depth accuracy

Window Layout

  • Top Left / Right: Left camera – RGB and Grayscale
  • Bottom Left / Right: Right camera – RGB and Grayscale
  • Main Window: Depth map generated using OpenCV Stereo Block Matching (BGM)

Enhancements

Webots does not provide built-in stereo cameras. A custom stereo pair was configured and depth estimation was improved by fusing stereo output with a rangefinder sensor.

RETURN TO HOME (LOW BATTERY FALLBACK)

Scenario

  • Battery preset to 15% at mission start
  • Rapid simulated depletion
  • Return-to-home triggered at 10% threshold

Behavior

  • LED blink alert (audio alert not captured)
  • Gradual motor power reduction
  • Autonomous return using logged movement history
  • Landing at home position

This validates emergency safety fallback under critical battery conditions.

Conclusion

The Martian arena simulation in Webots successfully demonstrates critical mission functionalities:

  • Stable altitude control
  • Safe landing zone detection
  • Stereo-based depth mapping
  • Emergency return-to-home protocol

Both manual and autonomous modes are fully operational. Further hardware testing will validate real-world system performance.