Robotic Arm Control Projects

IF826 - Robotics (Sistemas Inteligentes - Robótica)

CIn-UFPE

This repository contains the projects developed for the Robotics course at CIn-UFPE. The projects focus on implementing and controlling robotic systems, with emphasis on 2D robotic arm manipulation.

Project Structure

The repository is organized into projects, each containing one or more questions:

.
├── project1/
│   ├── q1/                    # Question 1: 2D Transformations
│   │   └── main.py           # SE2 transformations implementation
│   ├── q2/                    # Question 2: Robotic Arm
│   │   └── main.py           # FK/IK implementation
│   └── q3/                    # Question 3: Trajectory Planning
│       └── main.py           # Joint and Euclidean space trajectories
├── env_project/               # Virtual environment (not tracked)
├── .gitignore
└── README.md

Project 1: 2D Robotic Arm Control

Question 1: 2D Homogeneous Transformations

Located in project1/q1/, this implementation includes:

• SE(2) transformations for translation and rotation
• Functions for coordinate frame transformations
• Test cases for different reference frame scenarios

Question 2: Planar Robotic Arm with Two Rotational Joints

Located in project1/q2/, this implementation includes:

• Forward Kinematics (FK) implementation
• Inverse Kinematics (IK) implementation
• Simulation with link lengths a1 = a2 = 1m

Question 3: Trajectory Planning

Located in project1/q3/, this implementation includes:

• Joint-space trajectory planning with trapezoidal velocity profile
• Euclidean-space trajectory planning with straight-line motion
• Visualization using Robotics Toolbox
• Motion constraints (maximum velocity and acceleration)
• Interactive trajectory visualization with GIF generation

Project 2: TBD

Details will be added when the second project is assigned.

Dependencies

The project uses the following dependencies:

• Python 3.x
• NumPy
• Math (Python standard library)
• Robotics Toolbox (roboticstoolbox-python) - for visualization

Setup and Installation

1. Clone the repository:

git clone [repository-url]
cd robotic-arm-control

2. Set up Virtual Environment

On Linux/macOS:

# Install venv if not already installed
sudo apt-get install python3-venv  # For Ubuntu/Debian

# Create virtual environment
python3 -m venv env_project

# Activate virtual environment
source env_project/bin/activate

On Windows:

# Create virtual environment
python -m venv env_project

# Activate virtual environment
.\env_project\Scripts\activate

3. Install Dependencies

With the virtual environment activated (you should see (env_project) in your terminal):

pip install numpy roboticstoolbox-python

4. Deactivating the Virtual Environment

When you're done working on the project:

deactivate

Usage

With the virtual environment activated, you can run each question's implementation:

# For Question 1 (2D Transformations)
python3 -m project1.q1.main

# For Question 2 (Robotic Arm)
python3 -m project1.q2.main

# For Question 3 (Trajectory Planning)
python3 -m project1.q3.main

Implementation Details

Question 1: 2D Transformations

1. SE2_xy(x, y)

   • Creates a 2D homogeneous transformation matrix for translation
   • Parameters:
     • x: translation along x-axis (meters)
     • y: translation along y-axis (meters)
   • Returns: 3x3 homogeneous transformation matrix

2. SE2_theta(theta)

   • Creates a 2D homogeneous transformation matrix for rotation
   • Parameters:
     • theta: rotation angle around origin (radians)
   • Returns: 3x3 homogeneous transformation matrix

Question 2: Robotic Arm

1. Forward Kinematics (fk)

   • Calculates end-effector position and orientation
   • Parameters:
     • theta1: first joint angle (radians)
     • theta2: second joint angle (radians)
   • Returns: (x, y, theta) coordinates and orientation

2. Inverse Kinematics (ik)

   • Calculates joint angles for desired end-effector position
   • Parameters:
     • x: desired x-coordinate (meters)
     • y: desired y-coordinate (meters)
   • Returns: (theta1, theta2) joint angles

Question 3: Trajectory Planning

1. Joint Space Trajectory (traj_joint)

   • Plans a trajectory in joint space with trapezoidal velocity profile
   • Parameters:
     • theta1_init, theta2_init: initial joint angles
     • theta1_final, theta2_final: final joint angles
   • Returns: Array of joint configurations over time

2. Euclidean Space Trajectory (traj_eucl)

   • Plans a straight-line trajectory in Euclidean space
   • Parameters:
     • x_init, y_init: initial position
     • x_final, y_final: final position
   • Returns: Array of joint configurations over time

Both trajectory types:

• Respect maximum velocity (V_MAX) and acceleration (A_MAX) constraints
• Generate smooth motion profiles
• Provide visualization through Robotics Toolbox
• Export motion as GIF animations

Common Issues and Solutions

1. Virtual Environment Not Activating (Windows)

   • If you get a permission error, try running PowerShell as administrator
   • Make sure execution policy allows running scripts: Set-ExecutionPolicy RemoteSigned -Scope CurrentUser

2. Virtual Environment Not Found

   • Ensure you're in the project root directory when creating/activating the environment
   • Check if Python is properly installed and added to PATH

3. Robotics Toolbox Installation Issues

   • Make sure you have all required system dependencies installed
   • Try installing with pip: pip install roboticstoolbox-python --upgrade

Authors

• Students: Arthur Brito, Bianca Duarte, Matheus Boncsidai
• Course: IF826 - Robotics
• Institution: Centro de Informática, Universidade Federal de Pernambuco (CIn-UFPE)
• Year: 2024