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Obstacle detection in rail road crossings
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Installation of laser radar system for obstacle detection in a small single line rail road crossing in Sweden. This sis in winter and you can see ssnow flakes flying in the air . The demands are very hard here and we can operate in a temperature range down to - 40 degree C.
- The snow flakes do not have any effect on the measurements as they are signal processed away in the distance meter. Facts are that this system can see more far away than what the eyes can do in bad weather .
- Max range can be over 200 m but for this application we recommend to install as close as possible equal to typical 10-50 meter in distance from the centre of the rail road crossing.
- This system is set so it detects obstacles larger than 2 meter to avoid false alarms from pedestrians running in the close area with gates down. This happens and shall not cause a panic brake of the train.
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- Laser scanner for obstacle detection in crossings
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- This laser radar system scans an area in a rail road crossing to see if there are any obstacles in the area where there
- can be a collision with the train. car have engine problems and stop in a dangerous position. This system is independent of a lot of problems related to old designs like inductive sensors and magnetic field detectors. Thermal cameras and vision systems is no alternative as none is fail safe.
- The laser radar system is designed to be fail safe and is very reliable to the needed very high safety level.
- A unique feature is that we sort out all obstacle by the size and this makes it possible to see the difference between a
- pedestrian and a car as the car is larger and differently shaped. The shape make so we can send alarm related to the shape and not to any other factor. We can also see where the shape is located in the area and give different alarms.
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- Summary over applications in rail roads and trains
There are 2 models of the laser radar system.
This image shows the 3D scanner which scans a matrix to see if there are any obstacles in the wrong area.
The 2 D scanner is more like a radar system but is normally good enough for most crossings.
We can see objects as small as the legs of a person and decide how large the obstacle shall be to give a sharp red alarm and stop the train.
Weather penetration is very good and the system can measure at about twice the max range of what the eyes can see and detect.
The system is independent of light and color of the obstacle and the only decision factor is the shape and size and nothing else.
Installation is simple and price is attractive. Old less reliable systems were more expensive than this system.
This photo show the 3D matrix scanner unit with its gimbal mount and a laser distance meter.
Fail safe technology for high security and reliability.
The systems are fail safe to a high degree and designed to operate under the hardest demands. Fail safe is a complicated word but we know what it is and the system is designed around this idea. Whatever happens the system will detect the objects or send an alarm that something is wrong. We will never miss the obstacle and send the signal OK. The system is designed so that all technical problems gives an alarm output. It can not act so an obstacle is not view while the system send the signal OK. The output is a relay which is activated when OK. If power drops the relay is activated as it falls open. The relay is also a special security relay with a special design so it can not break mechanically and get closed.
2 D laser scanner
This system scans along a line and sense inside a preset distance range. If there is an object within a preset area / angle the system analyze it and decide if it is an obstacle or not. This is decided by the shape or area of the obstacle and is totally independent of color and temperature or magnetical characteristics. The system can be set to see objects larger than 2 meters in length which makes it detecting all cars but no pedestrians. Often people are running under the gates when they are down and this shall not cause an emergency stop of a train. The car at same place shall give an emergency stop and here the length algorithm is the best for selecting what you want to detect. This system can do this in a smart and selectable way. This system fulfills all normal needs for obstacle detection in rail road crossings.
3 D laser scanner
This system scanns in a matrix. which is two axis and not only along a line. This system can cower a larger and more square area in the same way as the 2 D system. It do also admit the possibility to see the height of obstacles and have this as a trig level. More points makes it slower but more detailed.
Technical characteristics in short
- Distance meter . Pulsed laser distance meter
- Vawe length . 905 nm in infrared area of spectra
- Max range . 200 m
- Min range . 5 m
- Distance resolution . 0,2 meter per each individual shot measured at 1 Sigma definition.
- Smallest detectable object. depends on time but in car detection mode we set it to 2 m or more
- Beam diameter at 50 meter . About 20 cm
- Beam diameter at aperture . 25 mm
- Laser safety class. 1 eye safe and totally harmless. Standard IEC 825-1 .
- Measuring speed . 140-170 Hz
- Weather penetration. About twice the visible range for the human eye
- Scanner. Rotating mirror design
- Scanner speed .About 1 revolution per sec.
- Operating voltage . 24 VDC max 4 ampere.
- Output signal . Relay in fail safe mode of operation. 2 A max 110 Volt.
- Main processor. PLC style system with standard software
- Fail safe electronics. In PLC and external supervising electronics
- Dimensions . 200x500x120 mm
- Encapsulation . IP 65 water proof for out door use
- Weight 5-6 Kg
Options for laser radar system
- Camera system for storage of obstacles for later analyze
- Different characteristics for the distance meter
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- Larger photos of an installation
- Here you can see a typical system in operation and some photos done by the system in shapr operation in a crossing.
- Here are some sharp trigged photos done with gates open and the cars driving through.
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Train at night time
- Pedestrian walking through and here the size
- was set to small object detection like pedestrian and bicycles.
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- This car is passing when the lamps are blinking
- and gates coming down. This is an illegal passage of the car.
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Illegal red light driver
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