=
and
࠵?
*
(࠵?
=T"
)
is the instantaneous intensity value of the
light/color sensor at sampling time
࠵?
=T"
and
࠵?࠵?
is the sampling time of the system in seconds.
4.
Distance to the block:
࠵?
Y
= Z(࠵?
\]
(࠵?
^
) − ࠵?
^
)
7
+ (࠵?
\]
(࠵?
^
) − ࠵?
^
)
7
where
a࠵?
\]
(࠵?
^
), ࠵?
\]
(࠵?
^
)b
is
the position of your UV when it stops and
(࠵?
^
, ࠵?
^
)
is the position of the block.
Your UV cannot
touch the block!
Try to stop as close to the block as possible. If you touch the block at point B,
you will automatically get zero points for
࠵?
K
in that trial.
5.
Platooning mode error:
In order to guarantee the fairness of project evaluation for platooning task, you will need to write
the ultrasonic sensor values to a local file in you EV3 in real-time with a sampling rate of
50ms
when you are doing the task. That is, the program should start recording the data at the same time
as your UV starts moving and stop recording once your UV is fully stopped at the red tape. The
TA will then extract the data points that your UV is actually following the UV
TA
and normalize
all your sensor readings in to a same range (e.g., [0, 50]) to calculate the C
3
value.
Three time-measurement will be used for the data extraction. Once your UV starts, TA will start a
stop watch, during this time, your UV should move forward and stops behind the UV
TA
with a
distance of 20 cm. As soon as the UV
TA
starts, we will record the first timestamp
t
1
. Your UV
should stop at the red tape and stop recording the data. The TA will also record the second time
step
t
2
once your UV reaches the red tape in case your UV does not stop properly.
The exact way how the TA extract the data points is based on the actual time your UV is
following the UV
TA
, which is the time period
t
2
-
t
1
. The TA will extract
t
2
-
t
1
/0.05 data points
starting from your data point recorded at
t
1
.
You will need to generate a different file for each trial with the timestamp starting from 0
and submit the data to TA after demonstration.
The data format of the light sensor reading
should be:
@[email protected]
Note:
If you cannot keep a perfect 50ms sampling rate, 50
±
5ms is also acceptable. If your data
recording does not meet the requirements, you will not get credit for the platooning task.
Ideally, if your UV can perfectly follow the UV
TA
, the distance
d
(
t
k
) between your UV and UV
TA
will always be a constant, so
C
5
is calculated as the standard deviation of your data set:

7
࠵?
c
= d
1
࠵?
f(࠵?(࠵?
=
) − ࠵?)
7
A
=B"
where
࠵?(࠵?
=
)
is the distance between you UV and UV
TA
at each sampling time
t
k
and
࠵?
is the average
distance between you UV and UV
TA
,
࠵?
is the number of data points.
C
5
indicates whether your UV
is maintaining a constant distance from the front UV
TA
.
6.
Red-tape stop mark:
C
6
= 100%, if the UV stops at the destination red mark;
C
6
= 0, if the UV fails
to stop at the red mark.


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- Spring '08
- Chow
- TA