robotics & sensor fusion for mechatronics autonomous vehicle navigation an obstacle avoidance...
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Robotics & Sensor Fusion for Mechatronics
Autonomous vehicle navigation
An Obstacle Avoidance Exercise
Luca Baglivo, Mariolino De Cecco
Robotics & Sensor Fusion for Mechatronics
We’re using two-dimensional grids: maps represented as images!
Robotics & Sensor Fusion for Mechatronics
From CAD to Image
Robotics & Sensor Fusion for Mechatronics
ATTRACTIVE POTENTIAL REPULSIVE POTENTIAL+
IMAGINE ROBOT AS A BALL ROLLING DOWN HILLS
Robotics & Sensor Fusion for Mechatronics
TOTAL POTENTIAL
Robotics & Sensor Fusion for Mechatronics
THE RESULTING FORCE IS THE GRADIENT AND GIVES DIRECTION TO THE ROBOT
This example is in the Matlab script “OstacoliQuadrati.m”
Robotics & Sensor Fusion for Mechatronics
POTENTIAL FIELDS METHOD FEATURES:
• AUTOMATIC PATH PLANNING FOR OBSTACLE AVOIDANCE
• IS BOTH A PLANNING & CONTROL STRATEGY ALL-IN-ONE
• BEST FOR LOCAL PATH PLANNING->UNEXPECTED OBSTACLES
• BE AWARE FROM LOCAL MINIMA! HARMONIC POTENTIAL
FUNCTIONS HAS PROVEN ONLY GLOBAL MINIMA
• NOT SUITABLE FOR HIGH PRECISION POSITIONING ON TARGET
Robotics & Sensor Fusion for Mechatronics
A FORMULATION
Robotics & Sensor Fusion for Mechatronics
A FORMULATION
Robotics & Sensor Fusion for Mechatronics
A FORMULATION
Robotics & Sensor Fusion for Mechatronics
A FORMULATION
Robotics & Sensor Fusion for Mechatronics
A FORMULATION
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORIDOR ALIGNMENT FOR LINE FOLLOWING
• The attractive potential can be defined punctually as desired.
• Build a vector field that point towards desired path.
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORRIDOR ALIGNMENT FOR LINE FOLLOWING
• How to define it
Lc
xF
yF
K yangles (+)
alphaK
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORIDOR ALIGNMENT FOR LINE FOLLOWING
• How to compute steering angle input
K y
alphaK delta
steering axis
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORIDOR ALIGNMENT FOR LINE FOLLOWING
• Now add the repulsive force vector Frep, and play …
K y
Frep Ftot
delta’
Robotics & Sensor Fusion for Mechatronics
OBJECT PICKING
A possible application for forklifts
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORIDOR ALIGNMENT FOR LINE FOLLOWING
• Try with:
• Tricycle robot forward velocity, point obstacle at (xF,yF) = (4,1.5)
yR
b
D1
Robotics & Sensor Fusion for Mechatronics
ANOTHER, NAIVE FORMULATION
A VIRTUAL CORIDOR ALIGNMENT FOR LINE FOLLOWING
• A control sketch
Robot kinematic
model
Steer control
velocity
steer angle
Potential field gradient vector
y
+ -alphaK
delta
kcontrol
Robotics & Sensor Fusion for Mechatronics
Bibliography
1. Siegwart R., Nourbakhsh I, Scaramuzza D., Introduction to Autonomous Mobile Robots
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