Four🍀bar

Four-bar is a simulator and a synthesizing tool for four-bar linkage mechanism.

use four_bar::FourBar;

// Get the trajectory of the coupler point
let path = FourBar::example().curve(360);

Features

• Simulation: Calculate the trajectory of the coupler point (or any point) on the planar/spherical four-bar linkage.
  • FourBar struct defines a planar four-bar linkage.
  • MFourBar struct defines a planar four-bar linkage for motion generation (rigid body guidance) synthesis.
  • SFourBar struct defines a spherical four-bar linkage.
  • *NormFourBar structs are the normalized versions of the above linkages without the translation, rotation, and scaling.
• Serialization: Serialize and deserialize four-bar linkages and their trajectories to/from a file via serde. (serde and csv feature)
• Plotting: Visualize the four-bar linkage and the trajectory of the coupler point. (plot feature)
• Synthesis: Find the dimensions of the four-bar linkage that will guide the coupler point through a desired trajectory. You can use the rayon feature to speed up the synthesis process. Also, the clap feature provides a CLI interface for the synthesis tool.
• Atlas: A collection of four-bar linkages with known trajectories. It can be used to find the best match for a given trajectory, which is similar to the synthesis process but without the optimization part. (atlas feature)
• GUI: A graphical user interface four-bar-ui is available at the repo with a web demo.

Citations

The synthesis technique is based on the paper by us:

• Chang, Y., Chang, JL., Lee, JJ. (2024). Atlas-Based Path Synthesis of Planar Four-Bar Linkages Using Elliptical Fourier Descriptors. In: Okada, M. (eds) Advances in Mechanism and Machine Science. IFToMM WC 2023. Mechanisms and Machine Science, vol 149. Springer, Cham. https://doi.org/10.1007/978-3-031-45709-8_20
• Chang, Y., Chang, JL. & Lee, JJ. Path Synthesis of Planar Four-bar Linkages for Closed and Open Curves Using Elliptical Fourier Descriptors. J Mech Sci Technol (2024). http://doi.org/10.1007/s12206-024-0436-y