Figure 1: Simulation of the Q-arm and Q-bot in Quanser Interactive Labs
Figure 2: CAD assembly model of the final mechanism
<aside> ⚠️ Problem Statement Project Green Sort: Advancing Recycling Accuracy Objectives:
Functional requirements:
The current recycling process is inefficient, with approximately 30% of items placed in recycling bins not being recyclable. This inefficiency leads to a significant loss of recyclable materials each year and contributes to environmental pollution. The situation is exacerbated by the inability of existing sorting facilities to effectively handle all types of recyclable materials, particularly those contaminated with food or beverage residue and black plastics.
The primary objective of this project is to develop a recycling station that identifies and accurately sorts different recyclable containers into the correct recycling categories utilizing sensors and robots, improving the efficiency of recycling processes and reducing waste. The mechanism must be able to lift the weight of the hopper and containers inside and drop the items in their designated locations. The mechanism must be capable of Identifying, classifying, and verifying containers for recyclability.
</aside>
Timeline of project (01/08/2024 - 03/04/2024)
The team demonstrated exceptional collaboration and individual effort, achieving all milestones within the designated timeframe. Each team member contributed significantly to every milestone, ensuring an equal distribution of tasks among all members. For this project, we were split into the computation and modelling sub-teams. I participated in the modelling sub-team in this project.
<aside> 🤔 To begin the project, everyone collaborated to list the project's objectives, constraints and functions. We considered both sub-teams and included objectives and constraints for computation and modelling. We also discussed the means of completing each function.
We also individually completed two initial concept sketches for our design using the linear and rotary actuators.
During the same time, the members of the computing sub-team demoed various sensors to use for this project. They created a brief description of how each sensor works and indicated the attribute that would be used to characterize each bin.
</aside>
Figure 3: Initial concept sketch for linear actuator
Table 2: Pros and cons of using each actuator
| Actuator type | Pros | Cons |
|---|---|---|
| Linear actuator | - Linear actuator seems easier to work with | |
| - Simplistic Design | - Using a single bar design may cause a finicky design (not reliable) | |
| - May not raise the hopper as high | ||
| Rotary actuator | - Efficient design | |
| - Scissor mechanism allows easy movement/collapsibility | - Design is less simple | |
| - Might have excess friction on pivot points that could interfere with the mechanism |
Figure 5: Deposit position detailed sketch
<aside> 🧱 Once we finalized our concepts we began modelling the parts on Autodesk Inventor. I started modelling initially without having specific measurements to first ensure the design would function properly. The model prototype I created didn't consider proper gear ratios as well as the rising height of the hopper. Once I discussed this with the team, we used my initial design as a point of reference when designing the specific model. Each member modelled a different part in this refined model, which we then put together in an assembly.
My contributions
My team’s contributions
</aside>
Figure 8: 3D printing progress of the modelled part
<aside> 🧪 During testing, we were able to test both the program for the Q-arm developed by the computing sub-team as well as the mechanism we developed. We assembled the mechanism exactly how we designed it in Autodesk Inventor and began testing with the rotary actuator. It was at this time both sub-teams were able to test and refine their designs to prepare them for the final demonstration.
</aside>
Figure 9: Physical Q-arm testing environment
Table 1: Objectives and constraints of the project
| Objectives | Constraints |
|---|---|
| Accurately sort and be aware of all the components as they move around | Total recycling weight cannot exceed 90 grams |
| Be aware of its surroundings and should be able to sort all materials by a variety of factors | Q-bot can only sort one type of container at a time |
| Must be durable and not break down during the process | Q-bot can only hold 3 items at once |
| The mechanism must be efficient | The mechanism must be connected to the base plate |
| Identify, classify, and verify containers for recyclability | Modelling must leave space for the actuator |
Figure 4: Initial concept sketch for rotary actuator
<aside> 🧠 As a part of the modelling sub-team, we collaborated on our initial concept sketches and discussed the pros and cons of each actuator. From this, we decided on the actuator to use in this project, which was the rotary actuator. With this, we created a refined sketch of the prototype in the transfer and deposit positions.
My contributions
My team’s contributions
</aside>
Figure 6: Transfer position detailed sketch
Figure 7: CAD model of the large gear
<aside> 📏 Once we put the assembly together with all the appropriate constraints and limits, we ran some tests with the motion to ensure the mechanism was moving the way we intended it to. Once all parts had been verified as functional, we began the fabrication of all the parts. For most parts, we decided to 3D print them, but we decided to laser cut the gears, as they required a high amount of detail and strength that the PLA and 3D printer would not be able to accomplish.
</aside>
Figure 10: Physical hopper mechanism testing environment
<aside> 🪞 I found this project to be very immersive and a great project to strengthen my understanding of 3D modelling and fabrication, as well as collaborating with different people on the same project. Before this project, I had minimal experience using Autodesk Inventor and had difficulties modelling some objects in 3D. This project allowed me to improve my skills by designing detailed and functional parts in Autodesk Inventor. I also gained knowledge on creating constraints and motion in assemblies in Autodesk Inventor. Additionally, this project allowed me to strengthen my communication and teamwork skills, as the parts used were designed by different members of the group, and were put all together in a single working assembly from communications and collaborating with my peers. This project was also my first experience with 3D printing and laser cutting. I was allowed to export my models made in Autodesk Inventor into a physical model using Prusa Slicer and the Prusa mk3 3D printer and the Trotec Speedy 300 laser cutter.
At the end of the project, the mechanism we designed was unable to list the full weight of the hopper and containers inside it, showing significant room for improvement. Something that could have been improved is the third filler gear in between the rotary actuator and the other gears connecting to the scissor mechanism. This gear did not provide significant benefit as it was only used to add some distance to the scissor mechanism. This gear could have been improved by making it slightly smaller than the large gears, but larger than the small gear. This would increase the gear ratio and increase the torque, allowing it to lift more weight. The reason this was not done earlier is, that while we know how much torque the rotary actuator is capable of, it is hard to visualize how much weight that translates to with our mechanism attached. Additionally, when we assembled the physical prototype, it was capable of being lifted with ease, so we proceeded with the assumption that it could lift the weight of the hopper, as we were no longer given additional testing time.
Through this project, I have gained a deeper understanding of the design process, modelling and simulation testing. Working collaboratively with my team members has also improved my ability to effectively communicate and work towards common objectives. I am confident that the knowledge and experience gained from this project will have a significant impact on my future endeavours in the field of design. By the end of this project, our team designed a functional recycling mechanism. This project is an excellent showcase of my progress in design, modelling and fabrication.
</aside>