2026 ASEE Annual Conference & Exposition

Analyses of four-bar and crank-slider linkages are core topics in any mechanical engineering curriculum. Topics include kinematics, forces, stresses, etc. Students use linkage-specific tools or MATLAB to calculate relevant dynamics of the linkage. In certain courses, students may also be prototyping table-top linkages to demonstrate their understanding.

In the above approach, there is one drawback, which is the lack of experimental verification of linkage prototypes with design criteria. A review of capstone project reports involving linkages carried out at ABC University showed that in over half of the projects, there is insufficient, or no data collected on the prototype to verify that it meets the design criteria. In many cases, the qualitative condition of the linkage moving is considered as satisfactory verification, which is not sufficient from an industry standpoint. Industrial sponsors of different capstone projects expect rigorous quantitative verification, and it is important to train students on this vital skill.

An evaluation of different courses points to the lack of quantitative verification in the curriculum. There are many reasons for not being able to integrate quantitative verification into existing curriculum. They may be lack of bandwidth in courses for laboratory exercises, lack of time in capstone projects, lack of resources and exercises necessary to provide adequate exposure among others.

This paper explains a laboratory exercise that was developed and implemented into XYZ course, which is a senior-level design and modeling course at ABC University. Two linkages, a four-bar with revolute joints and a crank-slider, were fitted with wired and wireless inertial measurement units (IMUs) for angle and angular velocity measurement of various links. Students collected data at various input speeds and compared them with theoretical data to compute the root mean squared error (RMSE). There were multiple objectives of this laboratory exercise. The first one was to showcase the importance of experimental verification and process of doing the same. The second objective was to demonstrate the need for using multiple sensors. The third was to emphasize the repeatability and reproducibility aspects, which are critical in an industrial setting.

Detailed instruction guides were presented to the students for data collection and data analysis portions of the exercise. Over 200 students participated in this activity during multiple instances of the course and the procedures were fine-tuned after each iteration. As part of the lab activity, students were also required to evaluate the linkage as well as compare the performance of various low-cost sensors. Detailed observations on the performance of the linkages, sensors as well as student expectations and outputs were examined and processed. Students also provided feedback on the lab activity along with learnings and other improvements that could be implemented from their perspective.

The paper will provide implementation details along with various results (including student evaluation) and future work recommendations that involve development of smaller prototypes to implement these laboratory exercises in similar courses at other universities.