Motion Analysis of a Four-bar Mechanism

Mingli Han, Prairie View A & M University, Mechanical Engineering

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Initial Publication Date: October 10, 2024

Summary

This project allows students to connect the classic four-bar linkage mechanism studied in class to a real-world example: a landing gear mechanism. Students will first design and simulate the motion of the landing gear using 3D CAD software. They will then use MATLAB to analyze the position, velocity, and acceleration of the mechanism. The focus of the analysis is to determine the relationship between the input and output angles of the mechanism.

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Learning Goals

1. Students apply theoretical four-bar linkage equations to analyze and predict the motion of a physical mechanism.

2. Students understand how varying the lengths of the four-bar linkage affects the system's motion constraints.

3. Students develop techniques to establish a relationship between the input and output angles of a four-bar linkage system.

4. Students learn that how accurate mathematical analysis can effectively characterize and predict the behavior of mechanical systems.

Context for Use

This is a 4 weeks group project assigned to the Kinematic Design and Analysis class which is offered to junior college students. Students should know how to use vectors to represent links, build vector loop equations, and matrix calculation to complete this project assignment. Matlab Onramp is assigned as homework at the beginning of the semester. Students are expected to understand the livescript provided by the instructor and use plot function to demonstrate their results. The plots will be incorporated into the reports.

Description and Teaching Materials

Chapter 4 of Robert L. Norton, Design of Machinery, 5th Edition, McGraw Hill.


Teaching Notes and Tips

This is a 4-week group project, and it's important for the instructor to monitor student progress throughout the duration of the project.


Assessment

Students are required to submit the following deliverables:

  1. The original CAD file of the mechanism.
  2. An animation file demonstrating the mechanism's motion.
  3. A report that includes plots for the position, velocity, and acceleration analysis of the mechanism.

References and Resources

Robert L. Norton, Design of Machinery, 5th Edition, McGraw Hill.