Arduino_de_EtherCAT

A demo of an EtherCAT network where both the master and slave are made with Arduono.

Control a 4-axis arm robot with 4 knobs.

WIZnet

Published November 02, 2023

Original author: lipoyang · JapanOriginal source (new tab)

0

Components

Hardware components

WIZnet - W5500 Ethernet Shield

x 1

Project description

Demo of EtherCAT with Arduino

A demo of an EtherCAT network where both the master and slave are made with Arduono.

Control a 4-axis arm robot with 4 knobs.

master

Hardware: Arduino Due + Ethernet Shield 2
Dependency library: SOEM4Arduino
Sketch: ec_master/ec_master.ino

Obtain the values of the 4 potentiometers from slave 1 and set the command values of the 4 micro servos to slave 2.

slave 1

Hardware: Arduino Uno + EasyCAT Shield
Dependent library: EasyCAT Library V2.0
Sketch: ec_slave1/ec_slave1.ino
Input device: Potentiometer (variable resistance B type 10kΩ) x 4 pieces

Create four analog signals of 0 to 5V using four potentiometers with knobs attached, and input them to A0 to A3 of Arduino Uno. These become the command values for the shoulders, elbows, wrists, and finger joints of slave 2's arm robot.

slave 2

Hardware: Arduino Uno + EasyCAT Shield
Dependent library: EasyCAT Library V2.0
Sketch: ec_slave2/ec_slave2.ino
Output device: Micro servo SG90 x 4 pieces

Connect four micro servos SG90 to pins 3, 4, 5, and 6 of Arduino Due. The power for the servo should not be taken from the Arduino's 5V, but should be supplied separately. The micro servo is attached to the arm robot and drives the joints of the shoulders, elbows, wrists, and fingers. The following kit was used for the arm robot.

Robot arm kit 2 for SG90/SG92R

*This kit says to use SG92R for the elbow joint, which requires the most torque, but I found that using SG92 caused significant vibration, so I used SG90 for all joints. (It may depend on the lot.)

movie

Impressions

It is a control system that can be easily overspecified.

The communication cycle of EtherCAT was actually measured to be approximately 1.3 msec. A serious Ethernet should not be like this, but the jitter is suppressed to less than a few usec. In the first place, the micro servo control pulse has a cycle of 20 msec, so even a communication cycle of 1.3 msec is too fast and is a waste of time.