Four Bar Linkage Optimization in Simscape

Four-bar linkage lengths are optimized using MATLAB to follow a desired trajectory.

This example shows a four-bar linkage modeled in Simscape Multibody that is optimized using MATLAB so that the tip of the linkage follows a desired trajectory.

Mechanical designers often wish to design mechanisms that will enable an end effector to follow a certain path. The lengths of the links and the position of the end effector influence the trajectory of the end effector in a complex kinematic relationship. Optimization algorithms can be used to tune those lengths to achieve the desired motion.

The process is similar to what is described in the video “Computational Design of Mechanical Characters” https://www.youtube.com/watch?v=DfznnKUwywQ

In this example, a parameter sweep is performed to see which trajectories are possible when varying a subset of the lengths. Then those lengths are tuned using MATLAB optimization algorithms until the resulting trajectory is within tolerances of the desired trajectory.

Please read the README.md file to get started.

Use the "Download" button above to get files compatible with the latest release of MATLAB.

You can also open this example in MATLAB Online.

For earlier MATLAB releases, use "Version History" tab above or these links:

• R2025b, R2025a, R2024b, R2024a, R2023b, R2023a, R2022b, R2022a, R2021b, R2021a, R2020b, R2020a, R2019b, R2019a, R2018b, R2018a, R2017b, R2017a

See how to use Simscape Multibody to model a cam-follower mechanism:

• https://www.mathworks.com/videos/modeling-contact-forces-in-a-cam-follower-94291.html

Learn more about multibody simulation with Simscape Multibody by watching this webinar

• https://www.mathworks.com/videos/multibody-simulation-with-simmechanics-81877.html

Learn how to use Simscape with

• Self-paced tutorials, including multi-domain systems, 3D mechanical systems, circuits, motors, and battery packs.
• Searching posts for the keyword "physical modeling".
• Stories from users: https://www.mathworks.com/solutions/physical-modeling.html