Multiplanetary Innovation Enterprise

N.A.S.A. R.M.C. Lunabotics Competition

This competition is held every year in Florida at the Kennedy Space Center with 50 teams from universities across the nation in attendance. This competition is used to simulate mining on the surface of the moon, via lunar simulant, and the challenges it presents. This is our third year participating in the Lunabotics competition. The Lunabotics team is focused on building a mining rover to compete in NASA's Robotic Mining Competition: Lunabotics. This competition requires a small, lightweight design simulating the build requirements for a real lunar project. The project also requires additional elements, including a STEM focused public outreach to K-12 education, and the use of systems engineering throughout the design process. Our team is broken down into several sub-team's to accomplish our goals:

The Chassis & Mobility Subsystem (CAM)

The Chassis & Drivetrain is in charge of the design, manufacturing, and testing of the lunabotcs chassis and drive train. We make sure that these two parts of the rover fit within competition constraints as requirements made by our team, that our designs are viable as well as optimal for the competition and our CAD is up to date and accurately represents what we have manufactured. We use a combination of CAD and FEA to create a chassis that fits our needs while also reducing the weight of the design by removing unneeded material found in our FEA analysis. Our drivetrain system is designed to reduce the number of motors needed to drive the rover white being able to fit in the limited build volume of the competition. Lastly, our wheels are 3D printed to reduce weight but are designed optimally to the extent that they can withstand 250lb of compressive force. We are constantly looking for ways to reduce weight while improving our structural integrity.

The Electrical Hardware & Data Acquisition Subsystem (EDAQ)

Our team is responsible for the coordination and management of all the electrical devices and wiring on the robot. We ensure that all crucial components such as the drivetrain, excavation motors, hopper conveyor, and actuation system are secured and receive the enough power from the battery to operate at their optimal capacity. All components are also linked together via communication wires which will transfer sensor information to the brain of the robot, the RoboRIO, and allow the Software and Communication team to control the robot quickly and reliably in both manual and autonomous mode. Every step is done properly and multiple safety measures have been taken to protect both the users and the robot from itself while in operation.

The Excavation Subsystem (EXC)

The Excavation sub-team handles the design, optimization, construction, and testing of the excavator for the Lunabotics robot. We make sure that our system is able to mine the required amount of rocks and regolith for the competition. The design of our system is very compact and has several intricate mechanisms that work together to activate, extend, and excavate material. Due to the size constraints given by the rules, our robot must start off in a compact form. The excavator starts off folded up on top of the hopper and hopper conveyor. The arms the excavator is attached to are able to pivot on bearings, which allow the excavator to fold down into its active position.
Our excavator uses a bucket ladder design with eight buckets attached to a chain that is driven by a motor. The buckets rotate around the frame on the chain. When the bucket takes a scoop of material, it brings it up to the top of the excavator and then dumps it into the hopper which is positioned to catch the incoming rocks and regolith. In order for the excavator to mine down deep enough to reach the desired rocks, the excavator needs to be able to extend. This extension is achieved by the use of an ACME rod and nut. The carriage of the excavator houses a motor and gearbox that drive a set of gears that rotate an ACME nut around the acme rod. This nut is held in place by two thrust bearings. The rotation of this nut facilitates the extension of the excavator into the ground. When the excavator digs as far as it can, it then uses the same mechanism to bring it back to its ready position.

The Hopper & Material Handling Subsystem (HOP)

The Hopper and Material Handling sub-team is in charge of designing the mechanisms to handle the excavated material during transportation and deposit it at the collection point, which is a sieve located on a wall of the arena. We designed the Hopper System to be a single bucket that can hold an entire kilogram of gravel in 1 duty cycle of the robot and can deposit it through the use of 4-bar linkages. To validate that the bucket frame, drive links, and attachment points will not fail under competition loads we conducted a comprehensive Finite Element Analysis on the system. The results of our FEA allowed us to proceed further with the linkage design. To off-load the material excavated, the 2 linear actuators located on the frame of the robot will extend lifting up the bucket in the air then the center linear actuator will extend to tip the bucket. The final details of our design are currently being worked out and the manufacturing will begin shortly.

The Rover Autonomy & Networking Subsystem (RAN)

The Software & Communication Team was created to have two major Spheres of influence on the Lunabotics project, which, as the name suggests, are writing Software for the Robot and controlling Communications throughout the Control system. The Former Sphere involves writing programs to control various actions around the robot using, preferably, closed-loop methods such as extending the excavator into the ground based on the input of an encoder and limit switches. This is done primarily through the use of the programming environment used in FRC, made by National Instruments, and known as "LabVIEW." Other Programming languages such as Python, C, and HTML are used for various other portions. You can thank us for this lovely website. When it comes to the competition, our subteam is the most crucial, as the majority of points won during the 15 minutes of operation are achieved through the use of automation.
The latter sphere of influence, the Communications aspect, is achieved through the utilization of various electrical components and programming methods such as a Raspberry Pi, Wireless Access Point, and RoboRIO. This combination of devices, languages, and connections makes communications one of the more complex portions of the subteam and an ongoing project to find the best way to send data to and from the robot.

The System Integration Sub-Team (SYS)

The System Integration sub team handles the system wide CAD model. Each sub team is in control of their respective sub models. System integration assembles all of the sub systems into the full assembly. System Integration also has a system of approving new changes to any sub system. When a sub system makes a change, they fill out a google sheet with the change they made and a path to the file they want updated. System integration ensures that the change that was made does not interfere with the rest of the system, and follows the naming convention. If the file meets the criteria, the change is accepted and fully added to the full system. System Integration also keeps track of the robots mass and overall dimensions to ensure the robot meets competition requirements. The estimated mass from the CAD and the dimensions are compared to the as-built systems to ensure they stay within the requirements. System Integration also keeps track of system wide and sub system testing matrices.

Updated: October 11, 2022