Xiaozheng Judy Xu

Attitude control is essential for space missions for target pointing, ground station tracking, and power and thermal management. This project focuses on determining the attitude of a micro-satellite using IMU, magnetometer and star tracker data. The performance of the Extended Kalman Filter and a Batch Filter is compared on real and simulated data. Download the paper for details and results.

Bravobot is a small robotic race car designed to race around the Olin Oval. It uses a Lidar and a camera for most of it's navigation and also has a GPS and a Compass for long term planning. I mainly worked on the navigation code using ROS and C++. I was part of a team of 8 classmates and together we built Bravobot from scratch. Download the report for details on Bravobot's design and performance.

Interactive Calculus is an app that allows students to learn calculus intuitively by drawing functions freehand and watching their derivatives and integrals graphically. I wrote this application with 2 other teammates using python, pygame and open CV. Check out the website for more information and to download the app from github.

Pixart is a creative abstract art generator that uses graphs and randomness. Sometimes, it draws patterns that resemble the continents, and other times it creates water color like images that remind you of the fall leaves in rain. It is written in java by two other classmates and me. Go to our github repository for more information and to download the app from github.

I designed and fabricated the mechanical system of azimuth. With a mission to grab salt and butter to you on the table, azimuth has a four-bar linkage with gears grab and lift system. It is fabricated using 3D printing and laser cutting. Check out the website for videos, design details and photos for azimuth.

For dynamics, I investigated how to control a spacecraft's orientation using reaction wheels. To find a best control strategy, I created a simple model and used matlab and quartonians to simulate the orientation of the spacecraft. Download the report to see my results and writing.

In this project for our Controls course, we tried to control a LEGO pendulum to stay in the upright position without using any sensors! We built a proportional and integral controller circuit using op-amps. It turns out, the pendulum will stay in the vertical position if it is on the verge of instability. That is, it will find the original downwards equilibrium position to be more unstable than the upright one. Download the report for details. Here is a video of our inverted pendulum.

In this project, we tried to levitate a magnet and control it at a certain distance below a coil magnet. Although we found a theoretical way to achieve the goal, it did not work completly in real life because of many reasons. We did manage to slow the magnet's ascent when being attracted to the coil. Download the report for details.