1. Initial Proposal

Problem Statement/Background:

Agriculture forms the backbone of many economies, yet challenges like labor shortages, increasing demand for food, and fluctuating climate patterns impede productivity. As a solution, an automatic farming robot mechanism can help the agricultural sector by streamlining tasks such as seeding, watering, and harvesting.

The modern agricultural industry faces a critical need for efficient and cost-effective farming methods. This development promises to not only optimize agricultural processes but also showcase the potential of advanced technology in tackling crucial global issues, making it both relevant and worthwhile to explore and implement.

Problem details and complexities:

The required motion/force/coordination profile necessitates a sophisticated design capable of intricate tasks, such as precise planting, selective harvesting, and adaptive navigation through uneven terrain.

Agricultural tasks demand a diverse range of movements, including delicate handling of crops, powerful digging, and gentle maneuvering around plants. These movements require a dynamic combination of precise force control, intricate coordination, and actuators. Simple joints lack the requisite degrees of freedom and precision for such complex tasks. In farming operations there is the need to adjust force for different soil types, delicacy for handling crops, and agility to navigate diverse terrains, surpassing the capabilities of basic joints, and limiting their ability to perform efficiently in diverse agricultural settings. 

Proposed scope of work for the final project:

For this project, we intend to create a mechanism that automates the planting process. It will dig out a section of soil, insert a seed into the hole, and push the soil back over the hole. This motion will be performed by two tools, whose motion will be coupled, with the primary actions of each tool timed to happen in a certain order. One tool will dig out a hole for the seed, and then push the dirt back into place. The other tool will drop a seed into the hole after the hole is dug and before it’s covered back up. We also intend for there to be a feature that moves the entire structure holding the tools over by a small distance so that the process can be repeated on a new patch of soil.

Proposed mechanism:

Our mechanism is designed into two main components: a prismatic joint and a linkage system. The prismatic joint allows our entire system to move in the x-direction. On top of the prismatic joint will be a wall in the y-direction that is fixed on the plate. This fixed wall will hold the first link in our linkage system. This linkage system has 5 links, one of which is connected to the shovel head. By using MotionGen, we were able to see that this system does allow our shovel head to fully rotate and change in height to shovel dirt. Not included in the drawing: on top of one of the links is a closed tube that holds the seed and water. We hope to this design in a way that when that link reaches a certain angle, it will slightly shift a circular closed plate inside the tube that will allow the water and seed to come out.

Answered Questions:

For the final project, we want to have a working mechanism that can perform the planting and compacting motion continuously. One interesting goal to have is to try and implement varying strengths for our digging mechanisms. The goal of the project is to have the mechanism complete its iterations. Accounting for harder ground, speed, different types of terrains, or moving to the next portion of land can all be built upon.

We will need to conduct a kinematic analysis of our joints and linkages to get the necessary output from our mechanism. We will need adequate acceleration, velocities, and movement to complete one iteration. This will tell us how much force we’re impacting the ground with. Additionally, it will also help us in our coordination for any additional mechanisms we want to add to the system such as a compacting dirt mechanism.

The most interesting part of this project is that it provides a solution to a real-life problem and we get to apply all the theory we learned to a working mechanism. The scalability of this project is also interesting; this mechanism could be tailored for small personal garden projects or industrial greenhouse farming perhaps. The most challenging part of this design will be incorporating multiple functions (digging, releasing the seed, and watering) into our system.

Preliminary Design Ideas:

Our initial design is to create a linkage system that can shovel dirt and move to a new area with a prismatic joint. As seen in the image below, our design was a 5-bar linkage system that has two degrees of freedom. Our prismatic joint would have a fixed wall on top that would act as a link to our linkage system. This would have allowed us to adjust the height/depth that our shovel head could dig into the ground and allow it to move across an x-axis across the prismatic joint. We eventually realized that two degrees of freedom would not be suitable for this project with only one motor. 

Initial Sketch

From MotionGen, we are able to determine that think linkage system has two degrees of freedom. By using MotionGen, we were able to achieve desirable motion profiles for digging. More about our design process and final design can be found in the next page. Shown below is the MotionGen for our initial design.

Linkage System in MotionGen