Fejemis

Project to automate the nice fejemis brush-cleaner

Autonomous Fejemis

Figure: Sketch of Fejemis from OnShape. The front part in yellow and black is a commercial brush for industry floor. The manual handle has been replaced with the Fejemis drive system. The front wheel can be lowered to allow the brush to be lifted when not in use.

The drawings can be accessed here: https://cad.onshape.com/documents/c3f44096b0f5e4646ed48e3f/w/670467f68cac02b087631e3d/e/e591dbcff8879adc4528ee2b

Onshape to robot

The URDF file is made using Onshape-to-robot There are added a dummy link for ROS and it is placed in its own ROS package.

Main electronics

Figure: The main hardware blocks. Two Teensy processors are the interface to the hardware. The drive processor controls the drive motors, safety and battery system. The front processor controls the brush and the front wheel to lift the brush. A main PC integrates the functionality with additional sensors to allow autonomous operation.

Electrical

Fejemis electrical wiring etc.

Teensy firmware

Fejemis Teensy software is build using standard Arduino library configurations. The interface to the main PC is organized as text-lines.

Battery control

The Fejemis battery control is a 24V system (2x3cell LiPo 5Ah) with power on-off and measurement electronics. There is on-board chargers for all batteries.

Brush unit

The Fejemis brush unit is a commercial brush that comes with its own battery (12V), charger and motor control. The unit is slightly modified to to allow measurement and control from the software.

Main software

Software repository

The Fejemis repository holds the documentation and source-code.

This section holds also the tool-chain instructions.

Bridge or Hardware abstraction

The hardware is integrated with the PC in a bridge-unit that also integrate a manual (remote control) possibility.

This Fejemis bridge should also provide the needed interface to ROS (to drive and control the operation).

ROS overview

Fejemis ROS

Reboot and startup

It seems like the Intel NUC has problems detecting the WiFi at first cold boot. This is fixed by a small script "/home/local/wifitest.sh" like:

#!/bin/bash
# test if WiFi interface is available
# if not, then reboot (after 2 minutes to allow stopping)
# save date and result to logfile
date >>/home/local/rebootinfo.txt
ifconfig wlp58s0  >>/home/local/rebootinfo.txt
# $? is the result of last call
if [ $? -eq 0 ]; then
   echo "wifi device wlp58s0 is Online" >>/home/local/rebootinfo.txt
else
   echo "wifi device wlp58s0 is Offline" >>/home/local/rebootinfo.txt
   sleep 120
   echo "time to reboot" >>/home/local/rebootinfo.txt
   reboot now
fi

The script is called from /etc/rc.local like:

/home/local/wifitest.sh &

When WiFi is up, it should connect to the "device" access point to get an IP (agreed with itservice) 10.199.253.209.

The Wifi is made available without any user (server mode) by modifying

/etc/NetworkManager/system-connections/device.nmconnection

The permissions line the connection section is changed to just

permissions=

Main functionality

Mapping and localization

The system should be able to systematically sweep the floor and therefore need knowledge of own position.

Sweeping control

The sweeping mission should be planned based on knowledge of the area to sweep and the schedule to do so.

The Fejemis should avoid swallowing loose cables and the hanging drone-net as some of the most troublesome obstacles.

Situation awareness

The Fejemis should be aware of the users of the facility and it should postpone cleaning if the situation is not sufficiently quiet.

Automatic charging

Charging requires 230V AC, and the Fejemis should be able to dock into a power outlet autonomously.

Garbage dumping

Garbage dumping is probably not going to be autonomous, but it would be nice with a warning when the dust-bin is full.