4-Bar Linkage Control System

Problem

Precise motion control of mechanical linkages requires accurate kinematic modeling, even when operating without direct position feedback.

Solution

Developed kinematic models initially in MATLAB, then implemented control logic in Python. Stepper motors were driven in parallel threads on a Raspberry Pi to achieve coordinated motion.

Architecture & Approach

Kinematic analysis performed in MATLAB and transposed into Python. Control software runs on a Raspberry Pi, managing multiple stepper motors concurrently. System behavior is monitored through logging and visualization tools.

Key Tradeoffs

• Lack of encoders required open-loop control with conservative motion planning
• Python simplified development but required careful timing management
• Simplified models improved stability at the cost of absolute precision

What I Learned

• Mechanical tolerances and backlash significantly affect real-world behavior
• Open-loop systems demand careful constraint management
• Visualization tools are essential when feedback sensors are unavailable