BEGINNER EV3 PROGRAMMING LESSON By: Droids Robotics Topics Covered: Switches.
EE887 Special Topics in Robotics
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Transcript of EE887 Special Topics in Robotics
EE887 Special Topics in Robotics
Paper Review
Initial Results in the Development
of a Guidance System Guidance System for a Powered Wheelchairfor a Powered Wheelchair2000. 6. 7.
BSCLLee Hyong Euk
General Idea of this paper
The autonomous navigation and the control of wheelchair
What are the issues in the wheelchair application? User Interface Obstacle avoidance Battery usage Seating Comport User demographics …
The navigation(guidance) of the wheelchair,Particularly the estimation and control of the system
Focus :
Requirement for Wheelchair Application
1. System must be more accurate2. System must be robust and repeatable3. Smooth ride to ensure user comport4. System should be simple and inexpensive5. Remember that the passenger is a human being
Requirement for Wheelchair Application
1. System must be more accurate2. System must be robust and repeatable3. Smooth ride to ensure user comport4. System should be simple and inexpensive5. Remember that the passenger is a human being
This requirements need ‘exact position estimation’
Experimental Wheelchair System
<Fig1. Experimental Wheelchair System>
<Fig2. Wheelchair Schematic>
512 by 480 pixel CCDBlack and white
1000 count-per revolutionOptical encoders
The camera view is not blocked by the user’s lower extremities.Everest & Jennings Powered Wheelchair
26 inches
Approach (1)
Odometry information(wheel rotation)External vision-based observation of surrounding envrionment
Combining and ApplyingExtended Kalman Filter algorithm
Optimal estimate of the wheelchair’s pose
Observation or measurement noise are modeled by Gaussian Distributed white process A set of diff. Equation which relate wheel motion to the position and orientation of the wh
eel chair are numerically integrated to produce the so-called “dead-reckoned”
Approach (2)
Automatic Guidance of the wheelchair “Teach-repeat” Procedure
The role of two video camera Detect the cues in the surroundings
Approach (2)
Automatic Guidance of the wheelchair “Teach-repeat” Procedure
The role of two video camera Detect the cues in the surroundings
: Reference hints for pos. estimation(ex. Desk, wall, or any fixed one in the workspace)
16 cues were used for this system (some objects in the experimental workspace)
‘cue’ is a priori information
Approach (3)
<Fig3. Wheelchair system guidance Flowchart>
Experiments
Test environment : home, office, classroom, laboratory, … Load : 200-lb human passenger and other equipments(PC, …) Floor surface : smooth poured concrete, tile, various carpet type
Room layout with nominal path
Ref. Path was taught in the Mechanical Systems and Robotics Lab.At the University of Notredam
Experiment Results (1)
Tracking Ref. Path Result
Total Time : 175s Avr. Speed : 0.5 ft/s 16 cues
Experiment Results (2)
Tracking Ref. Path Result with obstacle avoidance
Manual Control for obstacle avoidance
Experiment Results (3)
Speed Control : error between actual and estimated position
< Nominal Speed : 0.5ft/s > < Lower Speed : 0.3ft/s >
Avr. X error (in)
Avr. Y error (in)
Max. X error (in)
Max. Y error (in)
Nominal speed 1.006 1.167 2.884 2.393
Low speed 0.175 0.146 0.369 0.393
For 10 consecutive run case
Discussion
1. The extended Kalman filter accurately estimate the system’s pose(position & orientation)
2. The limitation of evaluating accuracy depend on the position of the ‘cue’s. a total of four cues were available for the last 8 ft of the path.
3. The obstacle avoidance strategy must be developed
4. User interface and other considerable factor is remained jobs.