Complete ROAMR setup

This is my robot in it's complete setup, of course I'll work on actually fixing everything in place properly, but all the hardware and such is there. I haven't been able to reliably send the Kinect data over wifi using ROS, so unfortunately the mapping and navigation algorithm isn't implemented yet, however I am controlling the robot from my laptop remotely over ROS. There are nodes running on each of the computers:

• The controlling laptop publishes steering data (this is what you see running in the terminal at the beginning)
• The robot in turn listens to this steering topic, and writes the appropriate signal to the Arduino onboard, which then controls the actual motors.
• The robot also publishes the Kinect data over ROS topics, however they don't seem to get through (my network stats show that the outgoing data constantly peaks at around 230KiB/s, but no actual images get displayed on the host computer) I believe this is because of the poor wifi card built into the laptop on to of the robot, I'm currently working on getting this to work
• The controlling laptop listens in to this data, and will, once it's working, run it through the ROS RGB-D SLAM algorithm.

Eventually, I will try to implement odometry for the robot so I can use the ROS gmapping algorithm instead, which produces 2D maps of the robots environment and better allows for navigation. i also expect the resulting maps will be much smaller in filesize - the RGB-D SLAM produced maps are often several GB large.

Here's the video:

ROAMR update

Albeit a small one. Here's two recent videos of the robot, still remote controlled at this stage, as I'm working on getting Kinect data sent via ROS, but the high bandwidth seems to be causing problems. However, I've already got a setup where I can mount my laptop to the robot, connect the Arduino via USB and steer the whole thing from a third computer over the Wifi network using ROS.





I'm using a 12V lead-acid battery and a L298 motor driver. My motors only take 6V, so the PWM pins are running at a maximum of 50%. I'll upload the code soon.

Preliminary robot control script

I haven't updated in a while, mainly because I kept on changing and adding things about the code which controls the robot. This mostly includes ROS (Robot Operating System) functionality related to Android devices, as my plan is to mount my G2 to the robot for things like GPS and orientation polling, automatic navigation or webcam feeds. I'm coming along on that code, but for now I'll just share the bare-bones python code which lets a user control the robot with the arrow buttons on a keyboard.

import serial
import pygame
import time
import sys
pygame.init()
forward=False
left=False
right=False
back=False
q=False
speed=220
screen = pygame.display.set_mode((100,100))

#ser=serial.Serial("/dev/ttyUSB0")
ser=serial.Serial("COM12")

while True:
    pygame.event.pump()
    key=pygame.key.get_pressed()

    forward=key[pygame.K_UP]
    left=key[pygame.K_LEFT]
    right=key[pygame.K_RIGHT]
    back=key[pygame.K_DOWN]
    q=key[pygame.K_q]
    
    if forward and not ((left or right) or back):
        LDirection="+"
        RDirection="+"
        LSpeed=chr(254)
        RSpeed=chr(254)
    elif back and not ((left or right) or forward):
        LDirection="-"
        RDirection="-"
        LSpeed=chr(254)
        RSpeed=chr(254)
    elif left and not ((forward or right) or back):
        LDirection="-"
        RDirection="+"
        LSpeed=chr(254)
        RSpeed=chr(254)
    elif right and not ((forward or left) or back):
        LDirection="+"
        RDirection="-"
        LSpeed=chr(254)
        RSpeed=chr(254)
    elif (forward and left) and not (right or back):
        LDirection="+"
        RDirection="+"
        LSpeed=chr(200)
        RSpeed=chr(254)
    elif (forward and right) and not (left or back):
        LDirection="+"
        RDirection="+"
        LSpeed=chr(254)
        RSpeed=chr(200)
    elif (back and right) and not (left or forward):
        LDirection="-"
        RDirection="-"
        LSpeed=chr(254)
        RSpeed=chr(200)
    elif (back and left) and not (right or forward):
        LDirection="-"
        RDirection="-"
        LSpeed=chr(200)
        RSpeed=chr(254)
    else:
        LDirection="-"
        RDirection="-"
        LSpeed=chr(0)
        RSpeed=chr(0)
    #checksum=ord(LDirection)+ord(LSpeed)+ord(RDirection)+ord(RSpeed)
    string="s"+LDirection+LSpeed+RDirection+RSpeed+"0"+"e"
    ser.write(string)
    print string
    if q:
        pygame.quit()
        sys.exit()
        ser.close()
    time.sleep(0.1)

As you can see, pygame is used for the keyboard input (which is probably not optimal, but I will later use the pygame window to display actual data). Checksum is not implemented yet, mainly because I'm lazy, and also because the robot has been working fine without it anyway. I'll still fix it at some point just for good practice.