# Week 3

There is a noteworthy educational project that proposes to bring robots to teach. This works inside of the many frontiers humanity is working actively to solve. One of the incentives are the X Prizes.

Details of the sensors and capabilities of a robot used as a teacher.

Image from https://www.ald.softbankrobotics.com

Image from https://www.ald.softbankrobotics.com

Pseudocode and Flowcharts

Image from Wikipedia

The way that all these robots send their control signals to their motors. But in order to move accurately they need a feedback loop. This proves to be one of the biggest challenges to face.

Overview of functions

http://playground.arduino.cc/Code/Function

https://www.arduino.cc/en/Reference/FunctionDeclaration

(Image from Wikipedia) Servomotors

One way to achieve that control, is not only moving but actually adjusting their position. So we call them servo-motors. They have a big contrast with the DC motors also by the way they are operated.

There are plenty of operational details about how servomotors are used with Arduino. Make sure you understand the difference between an inactive servo and a detached one.

Proportional Derivative Integral Control Loops ( P.I.D. )

From Wikipedia:

A proportional–integral–derivative controller (PID controller) is acontrol loop feedback mechanism (controller) commonly used in industrial control systems. A PID controller continuously calculates an error value as the difference between a measured process variable and a desired setpoint. The controller attempts to minimize the error over time by adjustment of a control variable, such as the position of a control valve, a damper, or the power supplied to a heating element, to a new value determined by a weighted sum

PID – Image from Wikipedia

PID over and undershooting – Image from Wikipedia

Filters & implementations

Low Pass

High Pass

PID trainer based on the Arduino library: link

Arduino library

Code example of a simple filter with Arduino: link