METRO DE MADRID is a railway company that
provides public transportation services to
Madrid and its metropolitan area. Currently, it
is the most extensive metro network in Spain,
with a length of 294 kilometers. With 302
stations, it is the third-largest network in
Europe by kilometers, after those in London and
Moscow. It has 2400 trains and makes an average
of 650 million trips a year, with 350 million
passengers.
Due to its large size, the
maintenance services are divided into
strategic areas to serve the 16 existing
lines optimally and exclusively. A breakdown
in a train can jeopardize the proper
functioning and punctuality of a line. That
is why the maintenance service needs to have
technological test tools to anticipate
problems through predictive maintenance.
Based on periodic, systematically conducted
braking performance tests, Metro de Madrid
can reliably and safely roll out
condition-based maintenance.
A series of measurements on three different
braking systems (pneumatic brake, electrical
brake, and emergency brake) lets Metro de Madrid
better plan their maintenance cycles and deploy
their predictive maintenance concept.
To perform brake testing on a total of 276
different metro cars, Metro de Madrid required a
precise, robust, and portable system that it
could install on the different trainsets. The
portable and rugged Q.brixx X system proofed to
be the ideal system for this application. A
Q.brixx XL A108-4M1 measurement module
acquires an acceleration signal from a Dytran
series 7577 high precision MEMS sensor. The
signal is sampled at a rate of 100 Hz, and
unwanted noise is then filtered out with a
fourth-order lowpass Butterworth filter. For
improved robustness, the Q.brixx X system is
installed inside a custom-made Pelicase.
Rugged data acquisition system for accelaration measurement
Before the braking test, the metro car is placed
on a horizontal track, and the accelerometer
offset is eliminated. The metro then performs an
acceleration and deceleration cycle. The braking
and rest endpoints are selected for each cycle.
The average steady-state acceleration and
deceleration values are then calculated. Next,
the average acceleration value during the rest
phase after the braking is calculated. This
value represents the mean value. Finally, the
average deceleration is calculated as the
absolute value of the difference between braking
deceleration and rest acceleration.
For user convenience and to ensure test
repeatability,
instrutechSOLUTIONS developed a custom
software application. The application was
written in Python, benefiting from the open and
flexible interfaces known as GI.connectivity,
which came free of charge with the DAQ system.
The Python application allows setting the
accelerator offset, displaying the measured
acceleration/deceleration signal, and providing
a pass/fail indication for the average
deceleration measured during brake testing.
Custom graphical user interface created with
Python
This test & measurement application showcases
the versatility of Gantner’s
Q.series X data acquisition system.
Combining of a flexible and modular hardware
platform, in combination with reliable data
exchange and interoperability through various
read/write interfaces, makes Gantner Instruments
one of the most sought-after companies for data
acquisition systems.