Rico's Nerd Cluster

「离开世界之前 一切都是过程」

Robotics Fundamentals - Velocities

Velocities, Accelerations, Derivative of Rotations

Rotation-Only Velocity and Acceleration Assume we have a world frame, a car frame, and a point. The car is rotating around the world frame, no translation.The point itself is moving as well, $p_c’...

Robotics - Quaternion Kinematics

Definition of Quaternion, Relationship Between Quaternion and Rotation Matrix

Definition of Quaternion Quaternions can be represented as: \[\begin{gather*} q = [s, x, y, z] = s + xi + yj + zk = s + v v = (i, j, k) \end{gather*}\] i, j, k are 3 complex dimensions, where: ...

Robotics Fundamentals - [ESKF Series 2] GPS and Its Coordinate System

RTK GPS, UTM Coordinates

There are two types of GNSS: Traditional single-point GPS: 10m accuracy, usually found in phones RTK (Real-Time-Kinematics) GPS. centimeter accuracy. It talks to a base station. Each module g...

Robotics Fundamentals - Rotations

BCH Formula, Instantaneous Rotation

Representations of Rotation A rotation, can be respresented as $so(3)$ (Lie Algebra of Special Orthogonal Group), or $SO(3)$, (Special Orthogonal Group) and rotation vector. Representation 1 A ro...

Robotics Fundamentals - Skew Matrix and Rotational Matrix

Introduction To Rotation Matrices, Lie Group and Lie Algebras

SO(3) SO(3) is the most common representation of rotation I’ve seen so far. \[\begin{gather*} \exp(\hat{\omega}) = I + \frac{sin(\theta)}{\theta} \hat{\omega} + \frac{1 - cos(\theta)}{\theta} \h...

Robotics - ROS1 Message Processing

Image Data

Data Manipulation Image Data Read, manipulate, and output image data 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 from sensor_msgs.msg import Image import nu...

Robotics - ROS1 Build Systems

catkin build, catkin make

catkin make Catkin make is basically a wrapper of the CMake and make. It’s part of the original Catkin build system, and build the entire workspace using a single Cmake invocation. catkin make...

Web Devel - web-crawler-toyota-rav4-crawler

Google Drive

Complete web crawler code can be found here Beautiful Soup and Selium Beautiful Soup is a Python library for parsing HTML and XML document. It is able to extract elements by class or ids in stati...

Web Devel - Storing Data on Google Drive

Google Drive

For personal projects, all AWS services will start charging once one service starts. Google drive on the other hand, gives everybody 5GB of storage for free. So for infrequent data read / write, Go...

Raspberry Pi 4B

Serial Setup

Set Up Rpi For Serial Communication Enable rpi serial: 1 sudo raspi-config Rpi has an option to allow a user to login to the system via serial. Choose no Answ...