FROM : The Director of TOX Metro

TO : CLEAN TECH, POHANG

SUBJECT : Self-moving Cleaning Robot for Uunderground Railways

FOREWORD

 In September 1999 the above enterprises decided to to collaborate on a joint project so as to build a cleaning system for Paris underground.
We have now completed the work and this report describes a new cleaning system for underground railway lines

SUMMARY

In order to fulfil the needs of the Metro de Paris a special robot has been designed . It takes into account the features of the Parisian lines and cleans either the ballast or the concrete lines with a blowing and sucking system. It also brushes the walls and the escape pavement along the lines.

DETAILS

General information

Description of the tunnels
 1/ Tunnels – They are tubular (inside dia 7.30m) or have a rectangular base ( 7.10 meter long) with a flat dome roof. (See Appendix)
 The last tunnels  have an emergency walking pavement ( about 0.60m wide) on side, the first tunnels have a pavement on each side.
 2/ Power supply :  a/ rolling stock : 750 V dc by third rail  b/ signals, lighting, etc… : 250 Vac
3/ Signals : they hang down from the roof or they are placed on the walls
4/ Obstacles on the walls : a/ signals : they project about 0.40m  in the tunnel and are 1.50 / 1.60m above the emergency pavement b/  electric cabinets and other cabinets. 1 to 1.5m * 0.50* 0.50 to 1.50m ( h,w,l)

Job to do
1/Picking up the debris and waste on the ground ( papers, cans , bottles). In the stations the floor is very dirty, the cleaning must be done every week, not in the tunnels.
2/ Picking up the debris and waste on the emergency pavement (not very dirty, must be done more rarely)
3/ Cleaning the dust of the tunnel  walls : not very dirty, must be done more rarely)
 
 
 

I - The Robot

General idea

We use an existing motor carriage ; we keep all the electric equipment and motors but we automate it so it is driverless.
We use ablowing system and a vacuum cleaner for the ground
We use brushes and vacuum cleaners for the walls and the emergency pavement
In addition to the space necessary for the driving, blowing, brushing and hoovering equipment, the rest of the carriage is divided in two : storage for the waste and an air filtration system.

A)Train detection
The line is fitted with a network composed of two wires which cut each other at regular intervals .

This network has a low voltage and the train has a sensor do detect the network. It measures true RMS or DC current using a sensor for low current. It provides a fully isolated analogue output proportional to the current range. This analog aoutput is used to control the spaeed and the train location.

Speed
The time to pass from one knot to another is used to calculate the speed.
If it is less than the rated time, the train must slow down. or accelerate if the time is between two knots is too long.

Train location
The wire system permits to know exactly where is the metro.
 
 
 

B) Main computer

• control program : It controls the movement of the robot. If there are problems on the robot, it makes the robot stop and send a signal to the control center.
• vision program : There is a camera to recognize the objects in front of the robot and in the wall. So it makes the brushes folded and the metro is already inputted. So this program compares two images - that of present time and inputted.

C) Antena

The robot can move by itself and also it can be remote controled. So this antena is used for that.
 

II - The cleaning system

-

 

A) Blowing unit and sucking unit

_ Hoovering is performed by one circuit.This circuit comprises a sucker near the blower, filters and a fan with characteristic :
 

- airflow : 60 000 m3/h
- total pressure : 400 daPa
- output : 110 kW

The airflow is divided in the carter by means of a hose and six air shutters.

_ The blowing is performed by a fan with characteristics :
 

- airflow : 24 000 m3/h
- total pressure : 200 daPa
- output : 18.5 kW

The airflow is devided in the carter by means of a hopper and three registers.

The filtration is achieved in two steps :

- first filtering : It’s a carried out through two separators aimed at ridding the air of heavy objects (storage is 2.5 m3 of wastes).
-air filtration : It’s carried out through filters placed on the carriages.

The airflow of each filter is 60 000 m3/h and is treated by two groups of 47 filters made of needled felt.

B) Protection of the carter

A camera watches the line 20 m ahead of the cleaning unit. If an obstacle is detected, the carter is automatically raised.

C) Operation of the blower and sucker

There are 4 vaccums on the robot , one for the ground and the others for the walls and the escape pavement.
On the concrete lines, the ground blower operates at full speed.
On the ballast line, the blower can also operate, but at lower speed (reducion by 50 %) : the strength of the air pressure simply makes the ballast move a little. This even light trash under the stones can be blown off.

D) Brushes

These brushes are for the wall and escape pavement. They are self-rotating and extendable. It cleans the pavement and the wall under the pavement.
Electric Torque motors (in lieu of compressed air) are used to retract and extend brushes, allowing for safety and reliability.

 

III - Number of Robots  to build
Estimated speed for the  vacuum cleaning : 2 to 3  km/h in the stations, which are very dirty, and 5 to 6 km/h in the tunnels, which require less cleaning.
There are well over 350 km of lines to clean, with about 20 km of stations and about 10 km elevated outside :
If we want to clean the stations and the elevated parts every week at the minimum and the tunnels every six months, we need three robots. But  it is not necessary to have  three identical robots . One  has the completeblowing /  hoovering  equipment  needed for the ground and the walls, and two have only the ground blowing /  hoovering equipment.

APPENDIX

Cross sections of the tunnels : a/ older tunnels  b/ recent ones

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