Autonomous Wheelchair Abigail Drury '10 Rittika Shamsuddin '12 Melissa Frechette '11 Professor Audrey Lee St. John Dr. Dan Barry Dr. William Kennedy 14 May 2010

Outline 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Final Thoughts 5. Tutorial Walk- Throughs

Outline 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Final Thoughts 5. 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 Home Wireless Network Wheelchai r Wireless Network

Testing Environment Clapp Lab

Testing Environment Clapp Lab

Testing Environment Clapp Lab

Testing Environment Clapp Hallway

Testing Environment Clapp Hallway - Doors

Testing Environment Kendade Bridge - Doors

Testing Environment Kendade Bridge

Testing Environment Kendade Bridge

Testing Environment Kendade Atrium

Testing Environment Kendade Atrium

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

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

Express Drive Mode in Action

Goal Drive Mode and MobileEyes

Wheelchair Goal Path

Goal Drive Mode and MobileEyes Person

Outline 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Final Thoughts 5. Tutorial Walk- 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 and Create 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 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Final Thoughts 5. Tutorial Walk- Throughs

Parameters & Observations

Level 1: Patients Level 2: Physicians Level 3: Developer User Level

Level 1: Patients Level 2: Physicians Level 3: Developer User 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

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 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 MaxVel TransAccel TransDecel SideClearanceAtSlowSpeed FrontPaddingAtSlowSpeed FrontPaddingAtFastSpeed 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 Wall TransDecel Overshooting the Goal

TransDecel Caution!!!! 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 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Final Thoughts 5. Tutorial Walk- Throughs

Blind Spots floor, 0 cm bottom lasers, 13 cm upper laser, 1.7 m

Blind Spots

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 1. General Project Overview 2. Overview of Interaction with the Wheelchair 3. Testing and Results 4. Tutorial Walk- Throughs