Digital Signal Processing Reference
In-Depth Information
The term called “period” is used as the basic temporal unit and it is defined
as the time elapsed from the instant any pressure applied to the accelerator
until the next stop. All together there were a total of 510 periods of data
from our driver set. The accelerator pedal pressure, the brake pedal pressure,
and the acceleration signal were the inputs to the prediction model as
proposed in (1). The acceleration signal is calculated as the simple time
gradient of the vehicle speed between two adjacent samples. In the data
collection phase, these three pieces of information were digitized at a
sampling rate of 1.0 kHz. However, we have down-sampled by a factor of
1:100 resulting at a data rate of 10 Hz in our experiments.
First, it is investigated how the prediction accuracy would change for
varying prediction orders
P=1, 2, 4, 8, 16, 32.
The results are displayed in
Figure 17.6 and they will be discussed later in this section after identifying
four specific cases we have looked into.
Next we have next studied the change in intra-driver prediction error
residual characteristics for four different cases:
1.
Acceleration only i.e., the case where accelerator pedal
pressure and the brake pedal pressure are forced to zero.
Acceleration and accelerator only
2.
and
brake pressure is
zero
Acceleration and brake only and accelerator is zero.
No term in Equation (1) is forced to zero; i.e., all three terms are
presents.
The resulting error defined in (2) is plotted in Figure 17-4 for each of these
four different scenarios together with the acceleration signal itself on the top.
3.
4.
Similarly, we have computed the inter-driver residual error signal as
shown in Figure 17.5, where
and
in equation (1) are from
one driver, while the LPC parameters
are from another driver.
As in other technique, it is extremely difficult to have a sense for
individuality of drivers.
