Programming modular snake robots with Arduino, Aalesund University College

Here a small presentation that I have prepared for our students so that they can learn how to program modular snake robots.

Presentation: Programming Modular Robots

Here a simple example.

// Copyright Filippo Sanfilippo

#include <SoftwareServo.h>
#include <math.h>

SoftwareServo servo1;
SoftwareServo servo2;

float position_angle1;
float position_angle2;
float amplitude=280;
float period=1000;
float phase1=0;
float phase2=120;
float offset=0;
//unsigned long time=0;



void setup()
{
  pinMode(13,OUTPUT);
  
  // This function sets a servo position to the maximum (or 180 degrees position).
  servo1.attach(10);
  servo1.setMaximumPulse(2200);
  servo2.attach(11);
  servo2.setMaximumPulse(2200);
  
  Serial.begin(9600);
}

void loop()
{
  position_angle1=amplitude*sin(2*PI*millis()/period+phase1)+offset;
  servo1.write(position_angle1);
  position_angle2=amplitude*sin(2*PI*millis()/period+phase2)+offset;
  servo2.write(position_angle2);
  SoftwareServo::refresh();
}

Here is a more advanced example with TimedActions (multi-threading).

// Copyright Filippo Sanfilippo

#include <TimedAction.h>
#include <SoftwareServo.h>
#include <math.h>

TimedAction thread1Action=TimedAction(100, thread1);
TimedAction thread2Action=TimedAction(100, thread2);

SoftwareServo servo1;
SoftwareServo servo2;

float position_angle1;
float position_angle2;
float amplitude=280;
float period=1000;
float phase1=0;
float phase2=120;
float offset=0;
//unsigned long time=0;



void setup()
{
  pinMode(13,OUTPUT);
  
  // This function sets a servo position to the maximum (or 180 degrees position).
  servo1.attach(10);
  servo1.setMaximumPulse(2200);
  servo2.attach(11);
  servo2.setMaximumPulse(2200);
  
  Serial.begin(9600);
}

void loop()
{
  thread1Action.check();
  thread2Action.check();
  SoftwareServo::refresh();
}

void thread1(){
  position_angle1=amplitude*sin(2*PI*millis()/period+phase1)+offset;
  servo1.write(position_angle1);
}
void thread2(){
  position_angle2=amplitude*sin(2*PI*millis()/period+phase2)+offset;
  servo2.write(position_angle2);
}

Other related papers to modular robots are listed in the following.

Filippo Sanfilippo, Houxiang Zhang, Kristin Ytterstad Pettersen, Gionata Salvietti and Domenico Prattichizzo. ModGrasp: an Open-Source Rapid-Prototyping Framework for Designing Low-Cost Sensorised Modular Hands. In Proceeding of the 5th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob), São Paulo, Brazil. 2014, 951–957.

Filippo Sanfilippo, Gionata Salvietti, Houxiang Zhang, Hans Petter Hildre and Domenico Prattichizzo. Efficient modular grasping: An iterative approach. In Proceedings of the 4th IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob), Rome, Italy. 2012, 1281–1286.

Cong Liu, Filippo Sanfilippo, Houxiang Zhang, Hans Petter Hildre, Chang Liu and Shusheng Bi. Locomotion Analysis of a Modular Pentapedal Walking Robot. In Proceedings of the 26th European Conference on Modelling and Simulation (ECMS), Koblenz, Germany. 2012, 441–447.