Final Presentation Prime Mobility Group Group Members: Fredrick Baggett William Crick Sean Maxon Project Advisor: Dr. Elliot Moore

 WHAT  WHAT: Adding Autonomous Functionality to a Power Wheelchair  WHY  WHY: To assist disabled individuals in homes, hospitals, and healthcare institutions.  SCOPE  SCOPE: Prototype proof of concept

 Assisted Driving Mode  Assisted Driving Mode - Chair will prevent head on collisions and block user commands that increase the likelihood of a collision.  Target Following Mode  Target Following Mode - Chair will autonomously follow a person wearing a predefined target symbol.

USB Camera Laptop CompactRIO Embedded Controller LIDAR Range Finder Joystick Power Wheelchair

SICK LMS-291  180 degree Field of View  75 Hz motor speed  1° angular resolution  ms response time  30 meter range “Laser Range Finder”

Read user’s desired direction Reference with zones containing obstacles Only allow movement (if < 4) obstacles are found

Target Emblem

 Low Frequency PWM  Experimentally Determined Parameters  Piecewise Linear Proportional Target Pulse width Camera Image Turning Radius Left Turn Proportional Control Right Turn Proportional Control

LabVIEW Front Panel, Displayed on Laptop

 What we tested:  Collision Avoidance  Object Detection  Target Tracking  Target Following  How we tested:  Set up obstacles and measured the distances at which they were detected.  Designed a target and measured the tracking and following specifications in different lighting conditions.

FeatureDescription Proposed Specification Actual Specification Collision Avoidance Front Distance (Stationary) > 0.5 m1.28 m Front Distance (Moving)>10 cm Side Clearance> 10 cm12 cm Object DetectionRange0.1 m – 5 m0.1 m – 4.5 m Field of View180° Target TrackingRange0.5 m – 3 m0 m – 7 m Field of View45°65° Target FollowingLinear Speed≤ 3 km/h2.4 km/h Angular Speed20° per sec16° per sec Heading Deviation< 20°7°

ProblemsSolutions LIDAR LIDAR reported ‘ghost’ points caused by reflections Mounted the LIDAR at a 10° downward angle. Chair drifts Chair drifts to the right when in motion Shifted the center camera region to the right to compensate. Slowacquisition rate Slow acquisition rate for LIDAR data causes delayed response Increased the length of the front LIDAR zone. Voltage regulation Voltage regulation issues USB webcam with laptop in place of Ethernet camera. Removed Shaft Encoders. USB webcam with laptop in place of Ethernet camera. Removed Shaft Encoders.

 Shaft encoders  Allow for navigation techniques such as dead reckoning.  Feedback mechanism to control the forward speed  Used in conjunction with the LIDAR to create a table of points that define a map of the environment  CAN protocol  Implementing CAN protocol would allow the microcontroller to communicate with the chair in the same way as the proprietary joystick. This could lead to more finely tuned control.

Collision avoidance: LIDAR Object Tracking: Camera + Image Processing Chair Control: Pulsed Feedback Control Behavior & Programming: Target Following Mode, Supervisory Control Mode

DIO Module 5-Way Switch At Rest MotionMoving Motion Decelerate AccelerateTurn left in place Veer left Turn right in place Veer right Start moving forward Start moving backwards Forward pinLeft pinRight pinReverse pin