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Train Collision Avoidance Using Vibration Sensor & Micro-Controller
Abstract
There is an increasing with the number of accidents at railroad railings. Collisions with train are generally
catastrophic, in that the destructive forces of a train usually no match for any other type of vehicle. Train collisions
form a major catastrophe, as they cause severe damage to life and property. Train collisions occur frequently eluding
all the latest technology. This paper deals about one of the efficient methods to avoid Train Collisions. This approach
uses the Vibration sensor and a Proximity LASER Detector and the communication mechanism of PLC (Power Line
Communication) to communicate the Critical Details about the Train to the Control Room.
Problem Definition
Train Collisions are of different types depending upon the circumstance. The head to head collisions are nowadays
mostly avoided with the advancement in the technology. Anti Collision Devices have knowledge embedded intelligence.
They take inputs from GPS satellite system for position updates and network among themselves for exchanging information
using their data radio modems to take decisions for timely auto-application of brakes to prevent dangerous ' head to head
collisions' . so we have to focus on the other potential reasons for the dangerous mishap or catastrophe. The other main
reasons for the collisions of Train are: 1.Train Derailment in curves and bends,2.Running Train collisions with the
Standing Train,3.Train Accidents in Slopes,4.Mis- signalling due to fog or Mist. Micro-controller and the embedded
technology is used in the coherence of the above operation with the sensors and relays and solenoid valves as
electromechanical switches. h Te Embedded technology has reached its peak so that the design can be so perfect with
time critical parameters.
Details about the problem
The avoidance problem in this paper has been split into individual blocks and then joined together with time
factors for the complete solution. Bottom to top approach is used. The different blocks used to avoid the Collisions
by above mentioned reasons are:
1.Gap Detector, 2.Vibration Sensor, 3.Proximity LASER Detector, 4.LED lighting or Fog penetrating
Lights, 5.FSK Modulator and FSK Demodulator (For Power Line Communication) .A Microcontroller for entire
Control. The Microcontroller is interfaced with the input sensing devices such as vibration sensor, Gap Detector and
proximity LASER Detector.
1. Gap Detector:
Figure 1. Gap Detector
In bends or curves, there should be gap between the rails of successive different paths. Even if there is a small gap, the
train would get mislead and travel in a different path which leads to collisions in most of the cases. Already there are
sensors to indicate the short circuiting of the gaps but practically even a small dust can short circuit the gap which
makes the current system futile sometimes. Hence we use adjustable mechanical or elastic claw to find the gap and
indicate the gap immediately to the Control Room. In the above figure, a rail road indicating a gap and next to it is a
Electrostatic; capacitance-type Gap Detector : VE Series.
2. Vibration Sensor: It uses piezoelectric effect to detect the vibrations in the rails due to the arrival or departure of
train and the direction of vibration indicate the arrival or departure. This could sense the train s position at roughly at
800 to 900 m away. This input is fed to the microcontroller. This could help in avoiding accidents between trains in
slopes because the arrival of one train found out using vibration sensor can be immediately sent to the Control Room
and the power supply can be switched off within 3 minutes so trains could be stopped without colliding each other.
Vibration or shock sensors are commonly used in alarm systems to activate an alarm whenever the devices to which
they are attached are touched, moved, or otherwise vibrated. Commercial vibration sensors use a piezoelectric
ceramic strain transducer attached to a metallic proof mass in order to respond to an externally imposed acceleration.
Piezoelectric vibration sensors used for detecting vibration from various vibration sources are generally classified into
two large types, resonant type and nonresonant type.
3. Proximity LASER Detector: Most of the collisions are of running train colliding with the Standing Train Types.
A LASER detector can be used to detect the presence of any train before the running train. D A laser proximity sensor
for a train includes a laser diode having front and rear facets. The diode generates a main laser signal and directs a
first portion thereof out of the front facet as a source beam. Focusing means focuses the source beam on a target, and
focuses the return beam reflected from the target into the laser diode through the front facet. The laser diode receives
the return light beam, provides it with a positive gain, mixes it with the main laser signal, and guides it out the rear
facet as a mixed beam. A detection focusing device focuses the mixed beam onto a PIN detector. The PIN detector
coherently detects the mixed beam and provides an output signal having a perturbation where the target enters the
focal field of the focusing optics. A processor detects the output signal from the PIN detector and may activate a
breaking mechanism in the train. The processor is also capable of determining the relative velocity between the train
and the target from measurement of the Doppler shifted signal or from the shape of the perturbation of the output
signal from the PIN detector.
4.LED or Fog penetrating Lights are very useful during mist or fog seasons, as, near the signals, still many
employees use explosives or other form of lights which involves the manual monitoring next to the signal 24*7. So,
detecting the arrival of signal using Vibration Sensor, the LED lights can be made to switch off automatically in the
signals reducing the manual labour and monitoring and the driver from the train could get the signal easily even in fog
times Any given snowy, foggy or rainy night can turn into a disaster because low visibility in these conditions can
maximize the potential of danger. Rough weather conditions call for precision driving, Using and installing fog lights
can help signals be seen better.
5.FSK Demodulation and Modulationower line communication(PLC), also called power line carrier, mains
communication, power line telecom(PLT), or power line networking (PLN) are terms describing several different
systems for using electric power lines to carry information over the powerline. Data rates over a power line
communication system vary widely. Low-frequency(about 100-200 KHz) carriers impressed on high-voltage
transmission lines may carry one or two analog voice circuits, or telemetry and control circuits with an equivalent data
rate of a few hundred bits per second; however, these circuits may be many miles(kilometres) long.