Today I Learned

Today I Learned: collection of notes, tips, tricks and stuff I learn from day to day working with software, robotics and other stuff.

Python

• Frameworks
  • pytest
  • Flask
  • FastAPI
  • Django
• Functions/Types
  • map
  • OrderedDict
  • dictionary.setdefault(keyname, value)

Robotics

• Behavior Tree: A behavior tree is a tree of hierarchical nodes that controls the flow of execution of “tasks”. Alternative to finite state machine, but more intuitive.

• Visual Servoing is a control system that uses feedback from a camera to control the movement of a robot or other object.
  • Reference: Lecture Notes
  • Software: ViSP Visual Servoing Plaform by IRIS - Inria.
• Hand-eye calibration

ROS

• ROS with Docker

SLAM

• Special Orthogonal Group $SO(n)$ \(\begin{equation} SO(n) = \{\mathbf{R}\in \mathbb{R}^{n\times n} | \mathbf{R}\mathbf{R}^\top=\mathbf{I}, \det{\mathbf{R}=1}\}. \end{equation}\)
• Rotation Matrix $\mathbf{R}$
• Transfer matrix \(T = \begin{bmatrix} \mathbf{R} & \mathbf{t}\\ \mathbf{0}^\top & 1 \end{bmatrix}\)
• Rodrigues’s Formula \(\begin{equation} \mathbf{R}=\cos\theta\mathbf{I}+(1-\cos\theta)\mathbf{n}\mathbf{n}^\top + \sin\theta \mathbf{n}^\wedge, \end{equation}\) where $\mathbf{R}$ is the rotation matrix, $\mathbf{n}$ is the rotation vector and $\theta$ is the rotation angle.
• Optical Flow
  • Tutorial
  • Video

C++

• Smart pointers
  • Unique pointers unique_ptr
  • Shared pointers shared_ptr
  • Weak pointers weak_ptr
• CMake
  • Modern CMake
    • cmake -S src -B build
    • cmake --build build
    • cmake --install build

Cloud

• Service Mesh
  • Introduction
  • Istio: An open-source service mesh project
• Cloud Native Architecture
  • Priciples for CNA

Tools

• Pikimov: Free web-based motion design and movie editor