Climbing method (SHC) specifically for lighting con-
trol purposes.
In ANA/RC, the design variable is the luminous
intensity of each lighting: the algorithm aims to min-
imize the power consumption while keeping the illu-
minance at the target level or above. It further enables
the control system to learn the effect of each light-
ing on each illuminance sensor by regression analysis
and, by changing the luminous intensity in response,
enables a quick transition to the optimum intensity.
The following is the flow of control by ANA/RC:
1. Each lighting lights up by initial luminance.
2. Each illuminance sensor transmits illuminance
information (current illuminance, target illumi-
nance) to the network. The electrical power meter
transmits power consumption information to the
network.
3. Each lighting acquires the information from step
2, and conducts evaluation of objective function
for current luminance.
4. Neighborhood is determined, which is the range
of change in luminance based on factor of influ-
ence and illuminance information.
5. The next luminance within the neighborhood is
randomly generated, and the lighting lights up by
that luminance.
6. Each illuminance sensor transmits illuminance in-
formation to the network. The electrical power
meter transmits power consumption information
to the network.
7. Each light acquires the information from step 6,
and conducts evaluation of objective function for
next luminance.
8. A regression analysis is conducted and the level
of influence is estimated.
9. If the objective function value is improved, the
next luminance is accepted. If this is not the case,
the lighting returns to the original luminance.
10. Steps 2‘9 are one search operation of the lumi-
nance value, which is repeated.
A search operation process (requiring about 2 sec-
onds) consists of steps 2) through 9) above: by iter-
ating this process, the system continues to learn how
the lighting affects the illuminance sensor measure-
ment until it realizes the target illuminance with min-
imum power consumption. Furthermore, by using the
influence level found in step 8) as a basis for the eval-
uation and generation of the next illuminance value,
the system can quickly optimize illuminance.
Next, we will see the objective function used in
this algorithm. The purpose of the intelligent lighting
system is to achieve each user’s desired illuminance,
and to minimize energy consumption. Thus, it can be
understood as an optimization problem in which each
light optimizes its own luminance. Following from
this, the luminance of each light is considered a de-
sign variable, under the constraint of the user’s target
illuminance, in resolving the problem of optimization
to minimize energy consumption. For this reason, the
objective function is set as in Eq. (1).
f = P+ w
n
∑
i=1
g
i
(1)
g
i
=
(It
i
− Ic
i
)
2
I
∗
≤ |It
i
− Ic
i
|
0 otherwise
(2)
P: Power consumption, w: Weight, Ic: Current
illuminance It: Target illuminance, n: Number of
target points
I
∗
: Threshold on illuminance difference
The objective function was derived from amount
of electric power P and illuminance constraint g
j
.
Also, changing weighting factor w enables changes
in the order of priority for electrical energy and illu-
minance constraint. The illuminance constraint is de-
cided so that a differencebetween current illuminance
and target illuminance within a threshold, as indicated
by Eq. (2)(N. Miyazaki, 2012).
4 POWER CONSUMPTION
CALCULATION METHOD
To calculate the objective function shown in Eq. (1),
power consumption is used. To calculate the objec-
tive function shown in Eq. (1), power consumption is
used. For this purpose, we used a Sharp Corporation
LED light in performing a preliminary experiment. In
the preliminary experiment, we confirmed that a rela-
tional expression between the power consumptionand
luminance exists, as shown in Fig. 3.
Figure 3: Relationship between luminance and electricity.
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