Obstacle Avoidance for Quadcopter with Ultrasonic Sensor

In 2017, I made an obstacle avoidance for quadcopter using an ultrasonic sensor as my undergraduate thesis project. The goal is to do proof of concept of an ellipsoid based guidance proposed in the following paper. The paper take a fixed-wing aircraft as the model. However, since implementing it on a fixed-wing model is an extremely laborious work, the implementation is done on a quadcopter.

Quadcopter System

To mimic the radar sensing, in this project, I used an rotating ultrasonic. The ultrasonic is rotated by using a servo that is commanded through a microcontroller, Arduino. The sensing result is estimated as an ellipsoid geometry, considering the size and orientation of the obstacle as well as aircraft velocity vector. A contact point is set as a guidance.

List of Prime Numbers

Recently I had an interview for an internship position with Volocopter. It is an Urban Air Mobility (UAM) company based in Germany. As far as I know, this company is one of the most advance in UAM competition.

One part of the interview was an online coding. The interviewer asked me to “provide a list of all prime number up to 1000”. I found this question interesting as a there’s only one characteristic of a prime number.