Skip to main content

Robots behaving...

Reblogged from: http://scott-ltattempts.blogspot.co.uk/2011/05/robot-behaviours.html


Behaviour based robots was used in the teaching as way of getting the students to think out AI a little deeper and in particular Do we need Human Level intelligence? or rather Do we always need to aim for Human Level Intelligence?

Lego Mindstorms robot are a good vehicle for students to start trying out idea around behaviour-based robotics. They are inexpensive, programmable and with the LeJOS software installed on them; have behaviours built into the programming which is done in Java.

A good example to use comes from Bagnall's book (B Bagnall (2002) Core Lego Mindstorms: 

Programming the RCX in Java , ISBN: 978-0130093646)


code 1: HitWall

//Taken from Bagnall (2002)
import josx.robotics.*;
import josx.platform.rcx.*;
public class HitWall implements Behavior
{
public boolean takeControl()
{
return Sensor.S2.readBooleanValue();
}
public void suppress()
{
Motor.A.stop();
Motor.C.stop();
}
public void action()
{
Motor.A.backward();
Motor.C.backward();
try{Thread.sleep(1000);}catch(Exception e){}
Motor.A.stop();
try{Thread.sleep(300);}catch(Exception e){}
Motor.C.stop();
}
}

Code 2: DriveForward

//Taken from Bagnall (2002)

import josx.robotics.*;
import josx.platform.rcx.*;
public class DriveForward implements Behavior
{
public boolean takeControl()
{
return true;
}
public void suppress()
{
Motor.A.stop();
Motor.C.stop();
}
public void action()
{
Motor.A.forward();
Motor.C.forward();
}
}



Code 3: Bumper Car

import josx.robotics.*;
public class BumperCar
{
public static void main(String [] args)
{
Behavior b1=new DriveForward();
Behavior b2=new HitWall();
Behavior [] bArray ={b1,b2};
Arbitrator arby=new Arbitrator(bArray);
arby.start();
}
}

All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with.

Popular posts from this blog

Micro:bit, Servo control with Micropython or blocks

You can control servos (small ones) from a Micro:Bit directly. Following a link from the David Whale (Twitter ) , thank you, took me to a Kitronik blog post, https://www.kitronik.co.uk/blog/using-bbc-microbit-control-servo/, which has the answer.

The code uses Microsoft Blocks taken from the post, runs the servos 180 degrees and back again, when button A is pressed. It does exactly what it should. I am also using the Tower Pro SG90 servo.
Can it be replicated in Micropython? This is a new mini project, there seems to be little out there yet on how do this but the best so far is this video by PHILG2864:



The closest I have is the following, it is essentially there.
from microbit import *
pin0.set_analog_period(20)
while True:
    pin0.write_analog(180)
    sleep(1000)
    pin0.write_analog(1)
    sleep(1000)

Setting the time period to 20ms  pin0.set_analog_period(20)seems by experiment (and used in the video above) to be best value so far. The reason for pin0.write_analog(1)  set to 1 i…

mbots - graphical programming and Arduino

Makeblock (http://mblock.cc/mbot/) funded through Kickstarter the development of a new robot - mBot (https://www.kickstarter.com/projects/1818505613/mbot-49-educational-robot-for-each-kid) with the subtitle "$49 educational robot for each kid". What they came up with is a interesting system that uses their mBlock software, which resembles Scratch but produces code for Arduino, to program a robot with LEDs, light sensors and buzzer integrated on the main board; but also comes with sensors for line-following, ultrasonic sensor and with the version in the kickstarter reward a 16x8 LED matrix.

My impression so far it is really quite intuitive to work with, in the example above the robot:

moves forward;displays 'f' on the LED matrix; turns right;displays 'r' on the LED matrix;repeats until the on-board is pressed to stop the motors. 

What I like most though is seeing the graphical code turned into Arduino code - the potential to see the same thing done into two ways…

4Tronix Bit:Bot Neuron Controlled Edge follower

In thelast post I was playing with 4Tronix'sBit:Bot. In this post I will show the initial experimentation with an artificial neuron controlling the Bit:Bot to follow the edge of a line (it follows the left-hand side of the line).


The neurons (well two separate ones, S1 and S2) are produced using weighted sums - summing the weights x inputs [ right-hand sensor (rs) and left-hand sensor (ls)] plus a bias for each neuron in this case w[0] and w[3].







    net=w[0]+w[1]*rs+w[2]*ls           net2=w[3]+w[4]*rs+w[5]*ls

  If weighted sum >=0 then its output 1 otherwise 0 if net>=0:          s1=1     else:         s1=0
    if net2>=0:         s2=1     else:         s2=0
What actual causes S1 to be either 1 or 0 is all defined by a set of weights w (three for the first neurone, S1,  three for S2).
w=[0,-1,1,-1,1,-1]


Converting the outputs of the two neurones S1 and S2 into actions is shown below.