Project Overview

The Wall-E Vader project focused on designing an autonomous rover capable of navigating a predefined maze, localizing itself, avoiding obstacles, and completing tasks such as picking up and delivering a block to designated zones. The rover achieved SAE Level 5 autonomy by integrating obstacle avoidance, localization, and block manipulation into a single operational algorithm.

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Key Features and Strategies

Obstacle Avoidance

• Sensors:
  • Four ultrasonic sensors and two infrared (IR) sensors for precise obstacle detection and corner handling.
• Challenges Addressed:
  • Replaced unreliable ultrasonic corner sensors with IR sensors for improved detection.
  • Enhanced calibration and redesigned sensor mounts for consistent readings.
• Results:
  • Successfully avoided major collisions, enhancing the overall reliability of navigation.

Localization and Navigation

• Algorithm:
  • Employed histogram-based localization combined with a compass for orientation.
  • designed a heat map to visualize the rover's localization status
• Efficiency:
  • Localized within 1–2 maze squares of movement, leveraging predefined paths and headings.
• Execution:
  • Hard-coded paths simplified navigation but limited adaptability to environmental changes.

Heatmap overlayed on top of the known maze design

Block Pick-Up and Delivery

• Detection:
  • Dual time-of-flight sensors identified blocks based on vertical offsets.
• Manipulation:
  • Servo-powered rack-and-pinion claw picked up blocks, assisted by a funnel design to correct alignment errors.
• Challenges:
  • Sensor misalignments and mounting inconsistencies were mitigated but not fully eliminated.
  • Hard-coded paths required precise block placement within the maze.

Time-of-flight sensor layout

Integration

• All subsystems were combined seamlessly into a unified algorithm.
• Starting locations and transitions between tasks were carefully managed to ensure autonomous operation.

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Final Results

• Performance:
  • Completed the maze in 3 minutes 20 seconds, well under the 5-minute limit.
• Reliability:
  • Executed navigation, localization, and block delivery with minimal errors.
• Key Insights:
  • Accurate localization achieved via a compass-aided algorithm.
  • Gripper’s modular design allowed reliable block handling, though reliance on predefined conditions limited robustness.

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Recommendations and Improvements

Mechanical Design

• Improve structural integrity by replacing taped or glued components with robust mounts.
• Balance weight distribution to reduce the need for frequent motor recalibrations.

Algorithm Enhancements

• Transition from hard-coded paths to dynamic path planning algorithms for better adaptability.
• Implement real-time angle corrections during navigation and block handling.

Electrical Optimization

• Organize cable routing to simplify troubleshooting.
• Incorporate encoder feedback to improve movement precision.

Sensor Utilization

• Optimize sensor routines to reduce processing delays.
• Enhance the block-finding algorithm to handle arbitrary block placements.