For my senior design project, I joined RamBOTs. RamBOTs is a four-year robotics project with collaborators across many disciplines of engineering. With two electrical engineers, four computer engineers, three mechanical engineers, and three Vertically Integrated Project (VIP) members, the RamBOTs team is ready to advance the design and functionality of a quadrupedal robot, affectionately named Sparky. To be able to walk, dance, and more, Sparky incorporates technologies like inverse kinematics, sensor fusion, embedded programming, safety-focused power distribution, and machine learning. Our team aims to enrich our own education and hands-on experience while collaborating with Electrical and Computer Engineering (ECE) Outreach to inspire future engineers through an exciting and engaging project. 

I did my senior Honors Thesis on this project and published it on Mountain Scholar, I reccomend checking it out for deep technical detail: https://hdl.handle.net/10217/244431 

Robot Arm

This year RamBOTs has more mechanical engineering members than ever before so that we can achieve our ambitious goals for Sparky. The goal is to mount a robotic arm on top of Sparky so we can have it play fetch and pick up objects.

With my team, we started designing using the engineering design process to make decisions and justify them. We created decision matrices to help choose important factors about the arm like what type of motors to use, materials to use, how to make it look, and how to power it.

We decided on using servo motors for their strength, cost, and position control. We also decided to fabricate the arm out of PETG, since it is lightweight, durable, and easy to manufacture. With these decisions, we started designing.

I made a Matlab script that you could input the lengths of each link and approximate dimensions of the links to find the weights of them, which is used to find the torque at each motor so we knew what motors to design around.

Result

Rambot Mark II

We have started work on making a RamBOT Mark II that will be designed more from scratch. The original RamBOT is based on James Bruton's OpenDog V3, and a lot of people are able to recognize that and distracts people from all the work we have put into it to make it different and better. In order to have more freedom of design and set our robot apart from the others, we will be creating a new one from the ground up based on our requirements and research of how other people make quadrupedal robots.

We went over design questions and defined what we want for the new RamBOT, some of these include our desire to make it smaller and use more laser cut metal to look more professional.

First Sketches

This is a quick mockup sketch/model of the mark 2 that is very subject to change, but helps visualize motor configurations and how it might look. As for the colors in this, orange represents the motor, green is a mounting point, red is gearbox, and the pink is a pulley. On the top I was thinking of doing mounting rails like the Boston Dynamics dog does.

Second Sketch

After doing research into leg configurations, I decided to change the configuration to match that of Boston Dynamics, utilizing a ball screw mechanism. The motor directly drives a ball screw which linearly actuates the end of the knee. I want to use this because it is compact and reliable, being used in industry and ball screws are very effecient.