3. Research method
Search gas source on simulation
Gas diffusion model is necessary
Ant pheromone diffusion model
Behavioral algorithms construction
Insect pheromone source search behavior
model
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4. Diffusion model of gas
Diffusion model
Ap(x, y, t) = Ap(x, y, t − 1) + γdif Gp(x, y, t − 1)
+ (1 − γvap)Fp(x, y, t − 1)
Gp(x, y, t − 1) = Ap(x + 1, y, t − 1) + Ap(x − 1, y, t − 1)
+ Ap(x, y + 1, t − 1) + Ap(x, y − 1, t − 1)
− 5Ap(x, y, t − 1)
Evaporation phenomenon
Fp(x, y, t) = γvapFp(x, y, t − 1)
(x,y)
(x,y+1)
(x-1,y)
(x,y-1)
(x+1,y)
Inflow
Outflow 4 / 9
5. Determination of parameters
Evaporation parameter
γvap = −0.0443E2
c + 0.0039Ec + 0.993
= 0.953
Ec:Ethanol concentration [%]
Diffusion parameter
γdif = 0.024
Semiconductor
gas sensor
gas sensor
Ethanol source
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7. Insect pheromone behavior model
Ant
Random walk model
Male silkmoth
Straight-zigzag model
52%
16% 16%
16%
Forward
Backward
Left turn Right turn
Male
silkmoth
Surge
Zigzag
turn
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8. Simulation
Simulation conditions
Mobile robot
Two gas sensors
Initial position
(x, y, θ) = (1.0, 1.0, π/2)
v = 0.4 [m/s]
ω = π/2 [rad/s]
Ethanol source position
(x, y) = (1.0, 3.5)
Goal area
Radius within 0.3 [m]
0 1 2
0
2
4
Ethanol source
x [m]
y[m]
Random walk
Straight-Zigzag turn
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9. Conclusion
Gas source search simulation of mobile
robot
Insect pheromone behavior model
Gas diffusion simulation by diffusion
equation
Future work
A real machine verification
Reduce search time
Multiple gas sources
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10.
11. Gas density distinction
Compare GL and GR
If GL > GR ,Turn left
If GL < GR ,Turn right
GL，GR：Actual value [ppm]
SensorL SensorR
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