2D SCARA Forward Kinematics Visualizer (JavaFX)

📌 Overview

This project is a 2D SCARA robot forward kinematics visualizer developed using JavaFX. It allows users to interactively explore how joint angles and link lengths affect the pose and reachable workspace of a SCARA manipulator.

The application is designed for educational and demonstration purposes, with a strong focus on clarity, interactivity, and correct kinematic behavior.

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🎯 Objectives

• Visualize forward kinematics of a 2-DOF SCARA robot

• Understand the relationship between:

  • Joint angles (q1, q2)
  • Link lengths (a1, a2)
  • End-effector position and orientation

• Demonstrate robot workspace, joint limits, and motion history

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🧠 Core Concepts Implemented

• Forward kinematics (planar 2-link manipulator)
• World-to-screen coordinate transformation
• Workspace boundary visualization
• Joint limit checking
• Interactive UI controls using JavaFX

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🖥️ Features

🔹 Interactive Controls

• Sliders and text fields for:

  • Joint 1 angle (q1)
  • Joint 2 angle (q2)
  • Link length a1
  • Link length a2

• Values are synchronized between sliders and input fields

• Press Enter or click Draw to commit a pose

🔹 Visual Output

• Base, joint, and end-effector rendered on a canvas
• Clearly labeled joints (Base, J1, EE)
• Orientation arrow indicating end-effector direction
• Cartesian axes (+X, −X, +Y, −Y)

🔹 Workspace Visualization

• Outer workspace circle: maximum reach (a1 + a2)
• Inner workspace circle: unreachable region (|a1 − a2|)
• Workspace automatically scales to fit the canvas

🔹 Joint Limit Indication

• Configurable joint limits for q1 and q2

• Visual feedback:

  • Link turns red when limits are exceeded
  • Angle labels turn red when out of bounds

🔹 Trajectory Trail (Optional)

• Toggleable end-effector trail
• Displays the historical path of the end-effector
• Automatically clears when disabled

🔹 Reset Function

• Reset to a predefined “home pose”
• Clears trajectory history
• Restores default parameters

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🧮 Kinematic Model

The SCARA forward kinematics are defined as:

• Joint 1:

  • x₁ = a₁ cos(q₁)
  • y₁ = a₁ sin(q₁)

• End Effector:

  • x = a₁ cos(q₁) + a₂ cos(q₁ + q₂)
  • y = a₁ sin(q₁) + a₂ sin(q₁ + q₂)

All internal computations use radians, while the UI displays angles in degrees.

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🧰 Technology Stack

• Java (JDK 23)
• JavaFX 17 (LTS)
• FXML for UI layout
• Canvas-based rendering

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📂 Project Structure

• ScaraApplication Entry point of the JavaFX application

• ScaraController Handles UI logic, rendering, interaction, and validation

• Kinematics2D Contains forward kinematics calculations

• scara-view.fxml Defines the user interface layout

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🚀 How to Run

1. Ensure Java (JDK 17 or later) is installed
2. Ensure JavaFX 17 libraries are available
3. Run the ScaraApplication class

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🎓 Intended Use

• Robotics coursework (e.g., CSC4702 Robotic System Development)
• Forward kinematics demonstrations
• Teaching aid for planar robot manipulators
• Interactive exploration during presentations

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📈 Possible Future Enhancements

• Inverse kinematics solver
• Constant Cartesian-speed trajectory planning
• Collision or obstacle visualization
• Exporting trajectory data
• Multiple robot configurations

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📝 Author Notes

This project prioritizes correct kinematics, clear visualization, and user-friendly interaction over unnecessary complexity. All motion is deterministic and physically interpretable, making it suitable for both learning and assessment.

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