Autonomous Wheelchair Abigail Drury '10 Rittika Shamsuddin '12 Melissa Frechette '11 Professor...

Autonomous Wheelchair

Abigail Drury '10 Rittika Shamsuddin '12

Melissa Frechette '11

Professor Audrey Lee St. JohnDr. Dan Barry

Dr. William Kennedy

14 May 2010

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Outline

1. General Project Overview

2. Overview of Interaction with the Wheelchair

3. Testing and Results

4. Final Thoughts5. Tutorial Walk-

Throughs



Project Created by MobileRobots and Dr. Dan Barry Research team methodically tested and

developed comprehensive documentation Doing our first exchange of the the chair -

the first step to giving patients with impaired motor function the option for independent mobility and privacy

Working with the Wheelchair

First semester with research assistants

Objective was to determine optimal parameter lists

Majority of work done through wireless connection between wheelchair and PC





Wireless Networking



http://tradelinecom.com/images/WirelessHomeNetwork.jpg





Home Wireless

Network

Wheelchair Wireless Network

Testing Environment



Clapp 201 - Lab



Testing Environment

Clapp 201 - Lab



Testing Environment

Clapp Hallway



Testing Environment

Clapp Hallway - Doors



Testing Environment

Kendade Bridge - Doors



Testing Environment

Kendade Bridge



Testing Environment

Kendade Atrium

Laser Sensors

Laser sensors use light beams to measure distance The way the light returns to the sensor is used to

calculate the distance



http://www.philohome.com/sensors/lasersensor.htm

Sensors

Upper Sensor

Lower Back Sensor

Touch Screen

Three laser sensors One high, two low Scan on horizontal plane

Laser sensors are used for localization and path planning

Bump sensors in case laser sensors fail

User Interface

Currently uses a touch screen and keyboard/mouse as main I/O device.

In future, it will also support other interfaces



Manual Drive Mode

Smart Drive Mode

Express Drive Mode

Drive Modes

Manual Drive Mode

Smart Drive Mode

Express Drive Mode

Drive Modes - Manual

Manual Drive Mode

Smart Drive Mode

Express Drive Mode

Drive Modes - Smart

Manual Drive Mode

Smart Drive Mode

Express Drive Mode

Drive Modes - Express

Drive Modes - Express

Express Drive Mode in Action

QuickTime™ and aPhoto - JPEG decompressor


Goal Drive Mode and MobileEyes


Wheelchair

Goal

Path


Person

Outline





Throughs



3 Levels of Interaction

Basic User Tasks

Intermediate User Tasks

Advanced User Tasks

Basic User Tasks - Patient

How to Use the GUI How to Start Up the Chair How to Shut Down the Chair How to Recharge the Chair How to Move the Chair By Pushing How to Re-enable the Motors After E-Stop

Definition

GUI = Graphical User Interface

GUI The touch screen interface on the chair Will be able to

support other devices at later date

Start Up, Shut Down, Recharge Begin from the back of the chair

Begin from the screen

Begin by unplugging

Move By Pushing Just in case something goes wrong Motors disengaged Lever in back Patient may need to be able to tell someone

how

Re-enable the Motors After Emergency Stop

Two emergency stop buttons Immediately apply brakes and disable motors

Push the rectangular red button to get the motors back Once for joystick Twice to return to normal

Intermediate User Tasks-Doctor/Therapist

How to Use X-Windows How to Connect to the Wheelchair from a PC How to Open MobileEyes How to Localize the Robot How to Drive the Robot From MobileEyes How to Change Maps in MobileEyes How to Enable/Disable Goals on the Chair’s

Interface

What is X-Windows?

A way to display the touch screen graphics on a remote computer

Connect With X-Windows

Useful to be able to control the chair remotely as if in chair Ex: For choosing goals

What is MobileEyes?

The main way to handle the chair remotely The place to make maps, change goals, and

change parameters

Connect to the Chair & Open MobileEyes

Connecting remotely Change your IP address Connect to the network

Opening MobileEyes Username and password unnecessary Set the Robot Server

Localization Like using a map and compass – once

you’ve found where you are and what direction you’re facing, you’re not lost

Using MobileEyes to Localize and to Drive

Localizing Drag robot to correct spot on map and check

localization score Repeat as necessary

Buttons on top menu bar for Manual and Safe Drive

Goal list at bottom left

Change Maps in MobileEyes & Enable/ Disable Goals On Chair

Need to open both Map and LaserLocalizationMap to change maps

To enable/disable goals Go to Look & Feel, then Goal List

on wheelchair (Or X-Windows)

Choose goals from list

Chair Guru Tasks - Administrator/Developer

How to Create a New Map How to Create a New Goal on the Map How to Change Parameters

Create a New Map Drive the chair around so the upper sensor

can create the map With MobileEyes open

Edit Map andCreate New Goals

Clean up the new map Using tools in Mapper3

Add new goals in Mapper3 Save map to Chair

Change Parameters in MobileEyes

Go to Tools, then RobotConfig Parameters allow you to change things like

the speed of the chair and the size of the padding

Outline





Throughs



Parameters&

Observations

Level 1: Patients

Level 2: Physicians

Level 3: Developer

User Level

Level 1: PatientsLevel 2:

Physicians

Level 3: Developer

User LevelUser Level

1. What are parameters?

2. How to modify the parameters of the wheelchair?

3. What parameters to modify?

Important Questions

Parameters

Are variables. (*There might be restrictions)

Way of communication between user and computer .

Impacts the behavior of any computer system.

Parameter Analogy

No English! No Barks!

Parameter Analogy

Parameter Analogy

User

Parameter

Parameter = val1

Parameter = val2

Computer shows behavior1

Computer shows behavior2

How To Modify Parameters????

MobileEyes…

Used to change parameters.

Records values in mm & sec.

To Access Higher Parameters…

Set Parameter Priority to Expert

BUT What Parameters to

Modify????

Quite fast.

Starts and ends with a jerk.

Turning not smooth.

Does not go through doorways.

Almost runs into obstacles, before stopping.

Work with speed/velocity parameters

Perhaps parameters for rotation?

Padding parameters

Padding parameters

Main Concerns

Perhaps parameters for acceleration?

Parameter Lists Each Drive Mode different set of

parameters Same name similar function slightly

different implementation.

Parameter list – Express Drive

Robot Config - a short list; speed related. Path Planning Setting - full list for Express

Drive.

TeleOp Settings - full list for Smart Drive.

Parameter list - Smart Drive

List of Modified Parameters

MaxVelTransAccelTransDecel

SideClearanceAtSlowSpeedFrontPaddingAtSlowSpeedFrontPaddingAtFastSpeed

ForwardSideClearanceAtSlowSpeed

Procedural Standards

Test trials: 6 to 15 trials.

Distance of 6069mm (~6m).

When testing each parameter:

simulated a hospital setting.

patient’s point of view.

Procedural Standards

Over a distance of ~6m.

MaxVel Directly controls the speed. In Express Drive: MaxVel = 600 On average 8.3sec.

In Smart Drive: MaxVel = 900 On average 8.6sec .

TransAccel

Increasing value, decreases time to reach maximum speed.

In ExpressMode: TransAccel = 425

Lower value jerkier start.

TransDecel Slows down . Stopping distance = 1.5m.

In Express Mode: TransDecel = 175

If TransDecel < 175 : stops smoothly BUT overshoots goal.

Starting Goal

End Goal Wal

l

TransDecelOvershooting the Goal

TransDecelCaution!!!!

Do NOT change the value of this parameter!!!!!

Side Padding Determines how close an object can

approach.

In Express Drive: SideClearanceAtSlowSpeed = 50

In Smart Drive: ForwardSideClearanceAtSlowSpeed = 25

Values allow to go through doorways.

Front Padding Determines how close an object can

approach.

In Express Drive: FrontPaddingAtSlowSpeed = 300 Applies when speed < MaxVel.

FrontPaddingAtFastSpeed = 500 Applies when speed = MaxVel.

Challenges Overcoming the fear of making changes.

Could not figure out a way to measure the effect of RotVelMax.

Parameters with similar names.

Battery Life.

FIRE???

Results Starting and ending smoother.

Speed comfortable.

Can go through doorways (33.5 inches wide).

Stops at a safe distance.

Turning is smoother but still slightly jerky.

Outline





Throughs



Blind Spots

floor, 0 cm

bottom lasers, 13 cm

upper laser, 1.7 m



Blind Spots

http://www.yankodesign.com/images/design_news/2008/04/11/music_table.jpg

Final Observations

Chair cannot see: Objects shorter than 13 cm Objects only present between 13

cm and 1.7 m Hardware-based issue

Side padding can be a little scary for pedestrians Can be solved in future through

software

Cautions

Difficulty starting too close to an obstacle

Inability to see black objects

When Express Drive Mode Goes Wrong

Conclusions and Future Work



Wheelchair is in good shape, but needs work to improve safety Continued exchange

between the research group and Spaulding

Further documentation needs to be developed

On our way to giving patients with cerebral palsy the option for independent mobility and privacy

Thank You!A special thank you to Dr. Dan Barry,

Dr. William Kennedy, and MobileRobots

Questions?

Outline




4. Tutorial Walk-Throughs



Autonomous Wheelchair Abigail Drury '10 Rittika Shamsuddin '12 Melissa Frechette '11 Professor...

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