This is the electro-hydraulic brake system for the EcoPRT autonomous  vehicle project. This is an extension of the proportional brake control system project. The design uses two linear actuators pressing on two master-cylinders made for go-karts. There's a spring between the linear actuators and the master cylinders to increase the resolution between brake force and actuator position. This is the system used in the "Brake System Dynamics and Control for an Autonomous Personal Rapid Transit Vehicle" published in the ASME IMECE 2023 Conference proceedings.

I developed and built this prototype rover as a research project for the Engineering Mechanics and Space Systems Lab (EMSSL) at NC State University. The report for this project can be found here. The development of a small-scale prototype (3:10 scale) was done with the goal of testing and evaluating the terrestrial locomotion performance of the MAARCO rover’s propulsion system in real-world conditions. The prototype allows researchers not only to evaluate the rover’s capabilities more cost-effectively and efficiently than building a full-scale version but also to identify any design flaws, issues, or challenges that may arise before developing a full-scale rover. The small-scale prototype is 18.4 cm tall, 25.4 cm wide, and 33 cm long, and weighs approximately 4.5 kg. Its chassis comprises two quarter-inch thick 6061 aluminum waterjet cut plates spaced apart with three pieces of aluminum extrusion. The modular and easy-to-manufacture chassis enables switching out different helical drives designs with relative ease. The pair of helical drives are 3D printed with ABS plastic material to make them impact and wear resistant. The drive electronics consist of two 12 VDC brushed motors providing 133.2 kg.cm of torque, two brushed motor electronic speed controls (ESC), and a 3s 11.1V LiPo battery. The torque is transmitted to the helical drives via a set of GT2 timing belt pulleys and belts. The ESC’s receive a PWM signal and control the direction and speed of the motors. The PWM signal is either sent through an RC receiver allowing for the rover to be controlled manually for testing electronics and chassis components or through an Arduino allowing the rover to follow a specific set of commands for data collection and dynamic testing. The rovers sensors include an IMU and rotary encoders built into the motors. The chassis is designed to house loads of varying weights to analyze the effect of carrying different types of payloads.

The purpose of this project is to design an improved mechanism for John Deere Commercial Mowing to safely and easily control mower discharge during operation from seated position. The mechanism will allow the user to cut closer to solid objects without violating safety standards, decreasing mower performance, or reducing cut quality. This will increase operating efficiency and maintain operator/bystander safety by preventing unshielded discharge or unwanted movement of the discharge mechanism. My role on this project was to design the gear box that would actuate the mower chute and the baffle. I was able to come up with a design that allowed for delayed actuation of both so that the baffle was fully down before the chute began to raise ensuring complete control of the mowers discharge by the user. My team was able to create a fully functioning model that can be seen in the video below. This design won my team first place in the senior design competition and was kept by the senior design lab to demonstrate the full capabilities of the lab. 

This was the final project for a graduate level advanced dynamics course at NC State University. The project was to find a research paper with a 6DOF system, re-derive the dynamics of the system, and simulate the system to re-create the papers results. The paper chosen for this project was on the dynamics of a coin toss, or more accurately, a coin drop. The paper describes a coin that is dropped with an initial rotational velocity that then bounces along the floor until an energy condition is met. The dynamics equations were derived and then used to successfully simulate one of the conditions in the paper.  Linked below are two reports: report A details the derivation of the dynamics and part B details the simulation and compares results. 

Project Reports

This is a research project done with the EcoPRT autonomous vehicle. When a vehicle undergoes linear or lateral acceleration, it experiences load transfers that dynamically change the load on each tire. This change in load also changes the max braking force for each tire. The goal of this project was to increase braking efficiency and performance by proportioning the brakes in accordance with the load transference caused by linear and lateral accelerations. The purpose of proportioning is to apply more braking force to the tire that has an increase in load and apply less to the tire that lost load. The proportioning is meant to achieve that same total braking force that would be had if each tire received the same applied pressure without exceeding the limits of each tire causing skidding or excessive slipping.

The brake test rig is a project within the research project above. The purpose of the test rig is to measure the brake systems developed pressure and current drawn at any position. To be able to measure the actuators  position, current drawn, and pressure, an Arduino Uno was used in conjunction with a pressure transducer, current sensor, a potentiometer (to control actuator position), and the actuators position sensor (a linear potentiometer). The Arduino was coded so that it would print all the wanted information to the computer over the serial port. The data was then put into a text file.  A MatLab function was also written to read and graph the data from the text file.

This wheel alignment calibrator is a project from my work on the EcoPRT autonomous vehicle project. The purpose for this device are twofold: to align all four wheels to the vehicle frame, and to center the steering for calibration. Since the vehicle operates autonomously the center of steering has to be calibrated so that the vehicle knows where it is going. The wheel calibrator clamps to the frame and the two feet push up against the wheel. Then the measurements on the two legs can be read and the wheel can be adjusted until the measurements are the same. This allows for the steering to be centered and the wheels to be aligned preventing toe in/out. The parts sere both machined and water jet cut by the universities research machine shop, and then welded together by me using a MIG welder. 

This project is about designing and manufacturing the interior joint for the tie rod on the EcoPRT autonomous vehicle. The original design was a universal ball joint that experienced multiple failures during testing. I was responsible for designing and manufacturing the new joint. The new joint consists of a C shaped bracket and a ball joint rod end. I took both finite element analysis (FEA) stress tests and manufacturability into account when designing the joint. After designing the joint, I machined the joints (two were needed) on a Tormach 1100 PCNC milling machine that I programmed using Fusion 360. The joint was made using 1018 low carbon steel. This joint has not failed during any testing so far including a rollover, and has become the knew interior joint for the tie rod. 

This project is from my internship at KAM Tool & Die. The customer needed a shelf that was able to hold a metal plate in two positions and support it so that workers would not have their hands near the brake press. The issue was that where the plate needed to rotate around was an edge on the die itself, and so a normal hinge could not be be placed there. So, I created a model of the the die and drew two lines to represent where the plate needed to be positioned. Then a circle that was tangent to those two lines was made. I designed the shelf to rotate concentrically with the circle since I knew that a shelf attached to that hinge could be made colinear with the two lines. The center of the circle was still too close to the die for a normal pin hinge, so I designed a curved slot-and-groove hinge that allowed the shelf to rotate concentrically to the circle. The shelf was also made so that it could change position by push/pulling a rod as seen below. The ease of machining was also taken into account when designing. The customer was happy with the end result.