LURCH - The autonomous wheelchair

LURCH in DEI exploration

L.U.R.C.H. is the acronym of "Let Unleashed Robots Crawl the House". Click here for a brief description of the project, taken from the AIRLab website.

LURCH is an extended version of an electric commercial wheelchair (Rabbit by OttoBock) equipped with

1. Interface circuit for digital drive via radio serial link (XBee modules)
2. Two onboard computers (PCBricks), powered by wheelchair batteries
3. 7" touchscreen monitor (Xenarc 700TSW), 800x480 resolution (16:10 AR)
4. Two laser scanners Hokuyo URG 04LX
5. Colour camera FireI400 (resolution 640*480)
6. Accelerometer, gyroscope, magnetometer XSens MTi.

Main goals of the LURCH project are:

1. Add sensor and robotics functionality to the powered wheelchair.
2. Add various command interface, such as Joypad wireless, speech command, Brain Computer Interface.
3. Semiautonomous navigation with collision and obstacle avoidance.
4. Autonomous navigation by path planning and localization.

Function currently provided by LURCH:

1. Drive by original Joystick or Logitech RumblePad2 Wireless Joypad.
2. Obstacle identification using planar scanner laser.
3. Collision and Obstacle Avoidance basic behaviours.
4. Indoor localization by Fiducial Marker System
5. Path Planning and basic autonomous navigation.

Available Doumentation

- Documentation on interface circuit between wheelchair joystick and computer: Image:LurchCircuitDocument.pdf.

- How to modify the wheelchair joystick to adapt to interface circuit: File:LurchCircuitJoystick.pdf.

- Brief discussion about interface circuit between wheelchair joystick and computer: File:LurchCircuitJoystickBrief.pdf.

- Brief description about lurch project: File:LurchBriefDesc.pdf.

- Source code for PIC 18F452 microprocessor and Eagle project (schematic and board):LurchCircuitProject.zip(BROKEN LINK).

WARNING: the circuit was modified and the documentation is obsolete. New version will be published as soon as possible.

PCBricks Configuration

PCBrick-03 and PCBrick-05 feature Xubuntu Linux 7.10, Xfce Window Manager, Openchrome graphics drivers and eGalax touchscreen drivers v1.08.1227 (Drivers here). The touchscreen is configured and calibrated on both machines, hence it can be used with either one or the other indifferently.

LURCH YouTube Video

• External link

• External link

• External link

• External link

People Involved

Andrea Bonarini

MatteoMatteucci

Davide Migliore

GiulioFontana

Marco Dalli (Tesista)

Simone Ceriani (Tesista)

Laboratory work and risk analysis

Laboratory work for this project is mainly performed at AIRLab/Lambrate. It includes some mechanical work and electrical and electronic activity. Potentially risky activities are the following:

• Use of mechanical tools. Standard safety measures described in Safety norms will be followed.
• Use of soldering iron. Standard safety measures described in Safety norms will be followed.
• Transportation of heavy loads (e.g. robots). Standard safety measures described in Safety norms will be followed.
• Robot testing. Standard safety measures described in Safety norms will be followed.