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RoboNav 23-24: MRC & Main Rover
MRC: Mini Rover Challenge
Project Objective
The goal of the MRC project was to design and build a functional mini rover capable of completing a series of tasks in a competitive setting, including object retrieval and manipulation, navigation, and obstacle avoidance. Emphasis was placed on modularity, durability, and efficient operation.
MRC Competition in February 2024
Mars Exploration Rover
Impact of Work
The MRC provides valuable experience in designing and building autonomous systems in a constrained environment. It teaches skills in robotics, mechanical engineering, and teamwork.
The project serves as a stepping stone for future technologies like autonomous exploration, rescue operations, and space missions. These challenges mimic real-world complexities faced by robotics in unstructured environments, particularly in space exploration, humanitarian aid, and industrial applications.
My Role
I was a core member of the mechanical team responsible for designing and fabricating the rover’s mechanical systems. My work focused primarily on designing the rover's arm, but I was heavily involved with the chassis, wheels, legs, and overall structural integrity. I collaborated closely with the electrical team to ensure integration of the mechanical and electrical components.
Voltage Diagram
Servo Motor
My Contribution
As the lead mechanical member of the team, I was the most consistent attendee and played a pivotal role in taking the mini rover project from concept to design and fabrication. I was primarily responsible for the design of the rover’s arm, ensuring that it was both functional and lightweight. Additionally, I handled the fabrication of the majority of the rover, using tools like the bandsaw, sander, and 3D printers to bring the design to life. My contributions spanned across the entire project, ensuring that both the mechanical design and construction were aligned with the team’s goals.
Invention Studio (3D Printers)
Student Competition Center Shop
Chassis Design and Assembly
I designed the rover’s chassis, working in SolidWorks to create detailed CAD models and assembly drawings. The chassis was built using 1/16” aluminum sheets and 1” aluminum tubes, ensuring accuracy in manufacturing and assembly. This design provided a robust foundation for the rover while minimizing weight.
Chassis Subsystem CAD
Chassis Parts
Chassis Assembly
Arm Design and Assembly
I designed a custom motor-powered arm with two degrees of freedom (shoulder and wrist joints), utilizing lightweight materials such as 1” square aluminum tubing and PLA 3D printed parts. Servo motors were integrated to provide precise control of the arm's movements, allowing for flexibility in the rover’s capabilities.
Arm Subsystem CAD
Wrist Joint (Servo) and Hook
Overview of Main Aim
Shoulder Joint (Servo) & Arm Mount
Wheel Design Optimization
I worked on optimizing the wheel design to improve traction and turning precision. The wheels were redesigned from standard models to omni-wheels, enhancing the rover's mobility and ability to turn efficiently. This modification was key in improving the rover's handling in the competition's varied environments.
Wheel & Motor CAD
Front View of Traction Wheel
Side View of Traction Wheel
3D Printed Omni-Wheel Parts
Side View of Assembled Omni-Wheel
Leg Manufacturing and Assembly
I was responsible for the manufacturing and assembly of the rover’s legs, which included fabricating the aluminum supports and integrating 3D-printed components. This involved ensuring proper alignment of the parts, such as the crossbeam connectors and DC motor mounts, to guarantee stability and functionality. My work ensured the legs were fully operational, contributing to the rover's mobility and performance during the competition.
Leg Subassembly CAD
Constructed Legs
Assembly and Alignment Adjustments
During assembly, I addressed alignment challenges, particularly ensuring that bolt and nut interfaces were properly aligned. By making adjustments where necessary and refining assembly processes, I helped ensure the rover's structural integrity and smooth operation in the competition.
Final Rover
Challenges & Solutions
Mobility Issues
Old Wheels (High Friction)
Challenge: During Competition #1 in January, the rover struggled with turning on carpet due to high friction between the wheels and the surface. The standard wheels lacked the maneuverability needed for tight turns and precise movement on low-friction surfaces, which hindered the rover's ability to navigate effectively and perform key tasks.
Solution: Before Competition #2 in February, we redesigned the wheels and implemented two omni-wheels in the rear, allowing for movement in multiple directions simultaneously. This change significantly improved the rover’s ability to turn sharply and navigate more easily on carpet. Additionally, we removed the back aluminum tubes and plating to reduce weight, further enhancing the rover’s performance and efficiency during tasks requiring tight turns.
New Omniwheels
Assembly Alignment Issues
Challenge: During assembly, we faced misalignment between the bolt holes in various components, resulting from manufacturing tolerances. This issue caused delays, as we couldn’t properly align the parts and secure them with bolts, hindering our progress.
Solution: We addressed the alignment issues by adjusting the hole sizes and re-manufacturing parts as needed to ensure proper fitment. By making these adjustments, we were able to align the components accurately, allowing for smooth assembly and ensuring that all parts were securely attached for the final build.
Top View of Electrical Equipment on Competition #1 Robot
Tolerance Issues
Challenge: During assembly, we discovered that the 3D printed leg and chassis connecting tubes were not printed with enough tolerance, leading to tight fits when attempting to connect them with the aluminum tubes. This misalignment created challenges in securing the parts together, preventing smooth assembly and causing delays.
Solution: We reprinted the necessary 3D components with updated tolerances to ensure a better fit. For the remaining parts, we used a sander to carefully shave down the aluminum tubes, allowing them to fit more precisely into the 3D printed connectors. This experience emphasized the importance of accurate tolerancing in the design and manufacturing process to ensure seamless integration of different materials and components.
Belt Sander
Results
The final rover was fully functional and competitive in the Mini Rover Competition (MRC). We successfully completed key tasks, including picking up and placing objects, manipulating a large ball, and pressing a bonus button. Our team’s efforts culminated in winning the competition, showcasing the effectiveness of our design and collaboration.
This project allowed me to expand my knowledge of mechanical design and fabrication while deepening my understanding of team dynamics and problem-solving in a competitive setting. The hands-on experience reinforced my interest in robotics, solidifying my commitment to pursuing further opportunities in this field.
Robonav MRC Team 1 Competition #1.mp4Competition #1 Video
Robonav MRC Team 1 Competition #2.movCompetition #2 Video
Shaping Future Experience
This experience fueled my passion for robotics, particularly in competitive settings. The challenges we overcame in the MRC and the skills I developed during the project deepened my interest in the field of space exploration.
The MRC experience emphasized the importance of teamwork and the integration of mechanical and electrical systems. This was crucial in achieving the success of our rover, highlighting the value of collaboration in engineering projects.
Motivated by the success and challenges of MRC, I am now fully integrated into the design and manufacturing of the main URC rover and serve as a mentor to new MRC members, helping guide them through the design and fabrication processes.
Onboarding
Project Objective
After the success of the Mini Rover Challenge (MRC), the focus shifted towards refining and enhancing the rover's design and performance for the 2024 University Rover Challenge (URC). The goal was to improve the rover's arm functionality, specifically with more accurate positioning and better interaction with the rover's environment, as well as to improve the overall integration of the electrical systems.
Arm for URC 2024
Arm Module Wiring Diagram
Full Rover with Arm
Arm Kinematics
My Contribution
took the lead in refining the rover's arm by integrating an encoder to track the arm's absolute position and adding limit switches to ensure proper range and movement of the arm. As part of the design improvements, I worked with the team to shorten the arm and remove a joint to simplify its movement, making it more efficient.
Challenges & Solutions
Encoder Mounting
Challenge: Initially, the encoder mount had to be redesigned to fit the new arm configuration. The original mount wasn’t compatible with the shortened arm, so we designed a new mount that securely attached the encoder to the motor, ensuring accurate position tracking.
Solution: I updated the CAD design to fit the new arm structure, making sure the encoder was positioned for optimal accuracy. This allowed for better control of the arm's movements, enhancing precision during tasks.
New Encoder Mount
Limit Switches
Challenge: Installing the limit switches posed a challenge due to space constraints and the need to ensure they would reliably trigger at the correct moments without interfering with the arm's movement.
Solution: I carefully planned and tested the placement of the limit switches on the arm, ensuring they were aligned with the movement range. We made sure the wiring was properly routed, and the switches were accessible without hindering the arm's mobility.
Limit Switches
Arm Adjustments
Challenge: Shortening the arm and removing a joint caused changes in balance and reach that required re-evaluating the rover’s overall design and weight distribution.
Solution: I adjusted the frame and carefully measured to ensure the new arm length and configuration were optimal for the tasks in the competition, keeping the rover balanced and its range of motion suitable for all required activities.
Arm Bicep Beams
Arm During Cutting
Arm After Cutting
Rover with New Arm
Rover with Arm Manipulation
System Acceptance Review 2024
Watch the below System Acceptance Review video to get a complete overview of the rover for the 2024 competition.
Results
As a result of the design refinements and the integration of the encoder and limit switches, the rover performed significantly better in the URC competition. The team placed 27th out of 38 teams in the finals, originally competing with 102 teams from 15 countries. The adjustments to the arm system, along with the streamlined design and improved electrical integration, contributed to the rover’s enhanced functionality and overall performance in the competition.
Image Carousel: URC 2024 Competition
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