Autonomous Quadruped with Robotic Arm

Precision Weed Removal for Sustainable Agriculture

Duration:Jun - Dec 2024
Status:Completed & Published
Category:Agricultural Robotics
PythonPython
Raspberry PiRaspberry Pi
OpenCVOpenCV
C++C++
LinuxLinux
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Quadruped Robot Overview

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Project Overview

A precision agriculture solution that combines legged robotics, computer vision, and intelligent manipulation to address the critical challenge of sustainable weed management. This system represents a shift from chemical-intensive farming to mechanical intervention, utilizing a terrain-adaptive quadruped platform equipped with a 4-DOF robotic arm and real-time vision processing for autonomous weed detection and removal.

Developed at Sathyabama Institute of Science and Technology, this project addresses the environmental impact of chemical herbicides while reducing labor costs by 70% through autonomous operation.

Problem Statement

Traditional weed control methods pose significant challenges: manual weeding is labor-intensive and costly, while chemical herbicides harm the environment, contaminate soil and water, and contribute to herbicide-resistant weed strains. The agricultural sector requires an efficient, sustainable, and precise weed management system that operates effectively on uneven terrain typical of real-world farming environments.

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System Architecture & Components

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Technical Architecture

Locomotion System

Quadruped chassis with bio-inspired gait patterns providing stable navigation across rough agricultural terrain using adaptive control algorithms

Vision System

ESP32-CAM module with real-time computer vision processing to distinguish weeds from crops using deep learning models

Manipulation System

4-DOF robotic arm executing precise mechanical weed removal guided by inverse kinematics calculations

Hardware Specifications

  • β–ΈQuadruped Platform: 8-DOF locomotion (4 legs Γ— 2 DOF each)
  • β–ΈServo Motors: High-torque 35 kg/cm for leg actuation
  • β–ΈLeg Segments: Two 19 cm segments per leg (38 cm total reach)
  • β–Έ4-DOF Robotic Arm: 20 kg/cm precision servos with 3D-printed components
  • β–ΈRaspberry Pi: Central processing unit for coordination and vision
  • β–ΈESP32-CAM: Real-time video capture and streaming
  • β–Έ3-Axis Gyroscope/IMU: Balance monitoring and tilt compensation

Software Stack

  • β–ΈPython: Primary language for control algorithms and integration
  • β–ΈOpenCV: Image processing for weed detection and feature extraction
  • β–ΈNumPy: Numerical computations for IK and trajectory planning
  • β–ΈSLIP Model: Bio-inspired locomotion control for energy-efficient gaits
  • β–ΈInverse Kinematics: Mathematical framework for arm positioning
  • β–ΈDeep Learning: CNN-based weed/crop classification models
  • β–ΈVNC Server: Remote monitoring and wireless control
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Quadruped Locomotion & Gait Control

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Core Features & Capabilities

Autonomous Terrain Navigation

SLIP model-based control with 8-DOF locomotion providing superior mobility on muddy fields, uneven ground, and crop rows without soil compaction

Real-Time Weed Detection

CNN-based classification analyzing morphological features and color signatures with detection overlays for system verification

Precision Mechanical Intervention

3D position calculation with IK solver commanding 4-DOF arm for mechanical removal, eliminating chemical herbicides

Adaptive Control Systems

3-axis gyroscope with real-time orientation feedback compensating for body tilt and maintaining arm accuracy

Performance Specifications

8-DOF
Degrees of Freedom
35 kg/cm
Servo Torque
38 cm
Leg Reach
4-DOF
Arm DOF
70%
Labor Reduction
90%
Herbicide Reduction
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4-DOF Robotic Arm & Weed Removal Mechanism

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Implementation Highlights

🦿 Bio-Inspired Locomotion

The SLIP model (Spring-Loaded Inverted Pendulum) abstracts the quadruped as a point mass bouncing on compliant legs, enabling lightweight, computationally efficient control that generates natural gaits suitable for agricultural environments with minimal energy expenditure.

🎯 Inverse Kinematics Solver

For the 4-DOF arm, the IK problem involves computing joint angles θ₁, ΞΈβ‚‚, θ₃, ΞΈβ‚„ given desired end-effector position (x, y, z). The system implements geometric and algebraic methods to solve these equations in real-time, ensuring the arm reaches target weeds accurately.

πŸ‘οΈ Computer Vision Pipeline

The vision system preprocesses camera frames, applies segmentation to isolate vegetation, and uses trained CNN classifiers to distinguish crop species from weed species. Detected weed centroids are converted from image coordinates to world coordinates using camera calibration parameters.

βš–οΈ Dynamic Stability Control

The control algorithm continuously monitors gyroscope data to detect body roll, pitch, and yaw. When deviations exceed thresholds, the system adjusts leg servo positions to restore balance, preventing tip-overs on slopes or during arm extension movements.

Technical Challenges & Solutions

⚑ Terrain Adaptability

βœ“ SLIP model's inherent compliance and energy-aware trajectory synthesis enable robust performance. Four-point contact distributes weight, minimizing soil compaction

⚑ Real-Time Processing Constraints

βœ“ Optimized algorithms with reduced-resolution images and ESP32-CAM handling video encoding, offloading tasks from Raspberry Pi

⚑ Weed Classification Accuracy

βœ“ Training deep learning models on diverse datasets representing different field conditions and growth stages improves robustness

⚑ Power Management

βœ“ Efficient gait patterns minimizing energy expenditure per stride and power-optimized servo control strategies extend battery life

⚑ Arm-Base Coordination

βœ“ Gyroscope provides orientation feedback updating IK reference frame, compensating for body tilt and movement

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Field Testing & Real-World Operation

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Applications & Impact

Precision Weed Management

Targets individual weeds, reducing herbicide use by 90% compared to broadcast spraying

Labor Shortage Mitigation

Automates repetitive manual weeding tasks, reducing labor costs by 70%

Organic Farming

Enables chemical-free weed control, supporting organic certification requirements

Crop Health Monitoring

Vision system adaptable for detecting diseases, pests, or nutrient deficiencies

Targeted Pesticide Application

Robotic arm can be equipped with spraying nozzles for spot treatment

Environmental Sustainability

Eliminates soil and water contamination from chemical herbicides

Results & Validation

βœ“Functional locomotion across various terrains with stable SLIP model gaits
βœ“4-DOF arm demonstrated precise positioning and object manipulation
βœ“Real-time vision with object detection and overlaid bounding boxes
βœ“VNC server enabled wireless control with live gyroscope data
βœ“Integrated system autonomously detecting and executing removal actions
βœ“Paper submitted: 'Quadruped with Robotic Arm for Weed Removal In Fields'

Future Enhancements

β†’AI-Driven Decision Making: Reinforcement learning for adaptive field strategies
β†’Multi-Robot Coordination: Deploying fleets for faster coverage
β†’Advanced Sensors: Hyperspectral cameras for improved discrimination
β†’Extended Battery Life: Solar panel integration for all-day operation
β†’Cloud Connectivity: Real-time data upload for farm management systems
β†’Enhanced Mobility: Improved gait patterns for challenging terrains

Project Impact

This project successfully demonstrates the viability of combining quadruped robotics, computer vision, and intelligent manipulation for sustainable precision agriculture. By providing an environmentally friendly alternative to chemical herbicides while addressing labor challenges, this autonomous system represents a significant step toward the future of smart farming.

Team: Pilli Ashok Kumar (41130394), Podapala Venkat (41130396)
Guided by: Dr. T. Ravi, M.E., Ph.D., Head of Department
Institution: Sathyabama Institute of Science and Technology

Interested in This Project?

This project demonstrates advanced agricultural robotics, bio-inspired locomotion, and sustainable farming technology. Feel free to reach out for collaboration or technical discussions.