13.7 Conclusions & Future Work

Conclusions

We were able to successfully meet our initial objective of developing an automatic egg cracker robot that can crack an egg and separate the contents from the shells with only one actuator. This was accomplished through the design of a slider-crank system, rack and pinion system, and four-bar system lined up in series and synchronized through the use of intermittent motion. These systems were all actuated by a single stepper motor, with the provided motion precisely propagated through the design with just the push of a button. Through testing with confetti eggs, the egg cracker robot was able to crack a real egg, empty the yolk into a bowl, and push the shells out to the side with the four-bar linkages. Overall, we learned a lot about different robot mechanisms and how they can be elegantly combined to imitate organic motions, such as cracking an egg and emptying it into a bowl.

Lessons Learned

The most important lesson we learned throughout this project was that it is always best to put in a little extra time in the present to save a lot of time in the future. We performed thorough kinematic analysis on our mechanisms and this reduced the troubleshooting we had to perform later after we fabricated the links. Another aspect where we learned this lesson was with the TPU egg holders. It required multiple iterations to get the holders to be able to hold the eggshells. Some more precise measurements of the eggs early on could have expedited this process. Finally, we could have put more time in early on thinking about efficient ways to reduce friction. Once we got everything assembled, we had to make minor adjustments throughout the build (such as cutting a slot in one of the links and adding lubrication to the intermittent motion faces) in order for the stepper motor to be able to overcome the friction and run the system properly.

Another lesson we learned was the importance of having a fully assembled model early. A full model led us to encounter issues we had not even thought of when designing the egg cracker, such as sources of friction we had overlooked (as explained earlier) and minor cases of linkage collisions. Because we got our full model assembled with a few days to spare, we were able to go back and solve these problems that we had overlooked. We were able to re-cut a couple links to reduce friction. We were also able to adjust the out-of-plane spacing of the four-bar linkage to prevent collisions between the links and their hardware.

Future Work

There are a few areas of future work that could be applied to our project to make it an even more complete design. We believe that a couple more iterations on the TPU egg holders would allow the design to better accommodate eggs of all shapes and sizes. Our current iteration could handle most eggs but the largest and the smallest eggs proved difficult to use. Other minor improvements could be made to the bowl that catches the egg to insure that the shells and yolk stay separate. In addition, if the separation of egg whites and yolk is desired, a strainer arm could be designed that extends out with the push of a button to catch the yolk and release the whites.

Another area of future work would be to experiment with different motors to find one that will fully crack the egg without fail every time. Our motor we used was on the borderline of being able to crack real eggs so having a motor with a better factor of safety would be beneficial.

A more ambitious area to expand this project would be to design another mechanism that automatically loads the eggs into the egg holders to fully automate the design. Our vision for this project was that this robot could be used in an industrial kitchen or bakery to reliably and automatically crack eggs without the need for manual support, freeing up hands to perform other tasks.

Tips for Future Groups

One tip would be to start the theoretical analysis and CAD design of your project as soon as you can so you have ample time to iterate and fix issues that inevitably come up. CAD assemblies only show the ideal case; once all of the parts are fabricated and assembled, unforeseen problems such as interference and friction will pop up so it is important to have enough time to fix those for a successful project. Along a similar line, another tip would be to put a lot of effort into the kinematic and force analysis. The kinematic analysis determines the dimensions needed for all of the linkages and the force analysis decides how strong of a motor or actuator you will need. A final word of advice would be to document everything thoroughly, even the failures. Take photos of failed parts, videos of failed attempts, etc. These help further document the design process and show you how much you accomplished in a few short weeks.

Acknowledgements

We would first and foremost like to thank Dr. Symmank for her instruction throughout the semester. She provided us with the knowledge and tools we needed to successfully design and analyze our project. We would also like to thank Connor Hennig for his invaluable advice throughout the design and build process and for steering us in the right direction when we were unsure how to attack design or fabrication problems. Finally, we would like to thank the Texas Inventionworks and its staff for providing a space where we could successfully 3D print, laser cut, and build all of the components we needed to make this project possible.