4 Bar Linkage Simulator

4 Bar Linkage Simulator is an interactive engineering tool for studying the movement of a planar four-bar mechanism. It represents a system formed by an input crank, a coupler, a follower, and a fixed ground link. The simulator has no characters, plot, or campaign because its purpose is mechanical analysis. Users create different linkage configurations and observe how changes in geometry affect rotation, oscillation, velocity, and the path of the coupler.

Four Measurements Define the Mechanism

The input panel allows users to change the length of each link in millimeters. The crank can be set between 10 and 120 mm, while the coupler, follower, and ground link support larger values. A ground offset changes the vertical relationship between the fixed pivots. After receiving these measurements, the simulator applies the Grashof condition and classifies the mechanism according to the movement its links can complete.

Controlling Motion and Reading Data

The mechanism can be animated automatically or moved manually through a selected crank angle. Users can adjust rotational speed, choose clockwise or counterclockwise movement, and switch between open and crossed assembly circuits. A visible trace follows a point on the coupler, showing the curve produced during a complete cycle. Charts provide angular positions, velocities, transmission angles, joint velocity, and mechanical advantage.

The adjustable options include:

• Input crank, coupler, follower, and ground lengths
• Ground offset from −50 to 50 mm
• Rotation speed between 10 and 120 RPM
• Manual crank position from 0 to 360 degrees
• Open or crossed assembly configuration
• Coupler-path and motion-trace visibility
• Crank angle or time as the chart axis

Experiments Instead of Numbered Levels

4 Bar Linkage Simulator does not contain stages with fixed solutions. Progress comes from testing configurations and comparing their behavior. Presets provide examples of crank-rocker, double-crank, double-rocker, triple-rocker, and parallelogram mechanisms. The full-experiment function calculates results across an entire 360-degree rotation. Two designs can also be stored as Experiment A and Experiment B for direct comparison.