The purpose of this project was to combine all the skills and concepts we learned in class up to this point and apply them in a practical manner. Thus, we were tasked with designing a 2.5 DOF cartesian motion system. This motion system would integrate aspects of mechanical design work and electrical sub-systems design. Furthermore, we would develop the system from scratch, taking the design from the idealization phase to the prototyping phase. 

During the idealization phase, we had a basic idea of what we wanted to accomplish. After floating around several conceptual designs, we decided to go with a plant watering system. The design would consist of some gantry system that would move in the X-Y planes and give us two degrees of freedom.  As a starting point, I designed the initial concept as shown to the left and was determined to make the bar-slider set"universal" in the sense that we can easily connect one bar-slider to another bar slider with minimal work. 

 Our end-effector would allow us to apply a certain amount of water onto the plants. After consulting with our professor, we decided that a 12V solenoid was the best solution.  

The preliminary design consisted of three universal bar-slider set connected to each other. Each bar slider set would have two bars ends that would simply snap-fit to the aluminum extrusion with one end being a free end and the other housing the Nema-17 stepper motor. The sliders would be moved with the a belt that would be snap-fitted to the slider itself and the top bar would be secured to the sliders with the use of screws.

After completing the preliminary design, we discovered some significant design flaws. The construction of the bar ends causes the belt used to translate the sliders to rub against the aluminum extrusions. Furthermore, the gantry structure had some stability issues and the top bar-slider's weight would cause the sliders to flex. In addition, the belts were not able to be snap-fitted to the sliders. 

In order to resolve these issues, a full redesign of the system was carried out.  The bar ends were redesigned to allow the belt to travel completely above the aluminum extrusion and to mount to the bar with bolts instead of snap-fitting. Furthermore, grooves were implemented into the sliders to more effectively secure the belt to the slider.  In addition, there was a fourth bar added to the gantry with L-brackets that added stiffness to the system.  Please feel free to click through the image carousel on the right to see how the design evolved from preliminary to final design. 

After checking our tolerances, I 3D-printed all the bar ends, sliders, end effectors in preparation for the assembly. Once assembled, my teammates starting working the electronics and code that would actually control the motion of the end-effector. 

The system would be controlled with a Buddy Control Board from Prusa Research. This control board has been extensively used in other cartesian motion systems such as the Prusa Mini 3D Printer from Prusa Research, which provided us with extensive documentation. For this reason, we selected this board to control our system. On the software, we used Repetier to program g-code into the board to cause the stepper motors to rotate and move the sliders. Once the code and wiring was finished, we were able to successfully test our prototype as seen in the video done below. 

Overall, I am very pleased with the outcome of this project and I am very grateful to be able to see project from inception to the prototyping phase. Not only did I learn how to incrementally tweak a design until it works but also when to cut my losses and start over if needed. If I had to redesign this product,  I would attempt to make this into a "smart" system where it could detect if the moisture levels were low for a certain area and subsequently move to water that area. Please enjoy the video of our working prototype down below!