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Cleaning Automation 70.1 Background and Cleaning Automation Theory 1255

also be recoverable when cleaning areas that are

inaccessible to humans.

Signiﬁcant features of these two groups of cleaning

robots are highlighted below.

70.1.1 Floor Cleaning Robots

Without exception, ﬂoor cleaning systems utilize

wheel-driven mobile platforms. The conﬁguration of

the wheels varies depending on the case of application

and the maneuverability requirements. Kinematics with

two driven wheels and other caster wheels are often

used.

Sensor systems for obstacle detection and navi-

gation vary widely. Inexpensive infrared or ultrasonic

sensors and contact switches are employed in systems

for household use. The sensor data generated does

not provide a basis for optimized path planning in an

environment and such systems normally change their

direction of travel according to a given algorithm in-

tended to optimally cover a surface. It can be assumed

that theentire areahas been negotiated and cleaned after

an appropriate period of operation.

Floor cleaning systems for professionaluse predom-

inantly contain laser scanners to generate maps and

navigate. In this case, path planning and execution must

be optimized to clean a maximum surface area within

a speciﬁc time. Ultrasonic sensors and contact switches

are often employed additionally as collision sensors.

Objects suchas walls, shelves or the like are particularly

challenging when cleaning.On the one hand, safeguards

are needed to prevent people from getting pinned, for

instance, between the cleaning system and a wall. On

the other hand, laser scanners’ capability to generate

precise maps near a shelf is limited. Batteries supply

ﬂoor cleaning systems their power. To be cost effec-

tive, a ﬂoor cleaning system must be usable over several

hours. The several hours presently required to charge

a battery may hinder professional use. Floor cleaning

systems must furthermore be equipped with efﬁcient

cleaning systems.

70.1.2 Facade, Pool, Ventilation Duct,

and Sewer Line Cleaning Robots

Unlike ﬂoor cleaning robots that are normally used

on level ground and equipped with batteries, dust

reservoirs, and water tanks, other cleaning systems

for facades, pools, pipes, sewers, and ducts must be

supplied power through cables and cleaning medium

through hoses and, where necessary, must have a fall

arrester system or a recovery rope. The engineering and

money required to implement these essential compo-

nents, which constitute an indispensable infrastructure,

are quite substantial compared with ﬂoor cleaning

systems.

The use of cleaning robots on facades, in pools,

pipes, ducts, and sewer lines may require their adapta-

tion to ambient conditions that are highly unusual for

automated systems and to environments that are less

than ideal for robots. Variable ambient conditions such

as humidity, temperature, and light conditions place

great demands on components and, for example, neces-

sitate adapting and increasing the redundancy of sensor

systems for navigation. Given the high expectations on

system reliability, this is particularly important.

Facade Cleaning Robots

Facade cleaning robots are often remote-controlled sys-

tems that clean surfaces that are inaccessible to humans

or accessible only with great effort. However, isolated

fully automatic systems that operate without human

supervision are also in use, particularly in Europe.

Some of these systems were designed speciﬁcally for

a building during its planning phase. Remote-controlled

systems in particular are designed to be universal and

usable on a variety of buildings including their infra-

structures without structural modiﬁcations.

Facade cleaning robots come in many different de-

signs: wheel-driven systemsfor ﬂat and slightlyinclined

glass roofs, climbing systems with vacuum cups for

sharply inclined and vertical facades, and rail-guided

systems. As a rule, facade cleaning robots must be able

to navigate obstacles such as window framework and

other facade elements. The use of sensors to deter-

mine position constitutes a particular challenge since

they must deliver reliable data under the widest vari-

ety of outdoor weather conditions from rainto sunshine.

All the facade cleaning robots in operation today have

cables that supply electrical power and, depending on

the system, compressed air, water, and data commu-

nications. There are no known systems that operate

autonomously on facades without an umbilical.Whatis

more, measures often have to be taken to secure a robot

against falling [70.4]. Such measures have to be inte-

grated into the overall concept and, where necessary,

automated for fully automatic systems.

Pool Cleaning Robots

Pool cleaning robots have been in use for some 20years

to clean the bottoms and sides of swimming pools. The

Part G 70.1

1256 Part G Infrastructure and Service Automation

various manufacturers’ products function on the basis

of the same system. A tracked vehicle provides loco-

motion under water. Rotating brushes mounted on the

front and back of the unit loosen dirt, which is then suc-

tioned into a slot on the unit’s underside and pumped

through a ﬁlter. The water intake on the underside addi-

tionally increases the contact pressure, thus facilitating

controlled movement on the vertical sides of pools.

Pool cleaning robots use a minimum number of

sensors to orient themselves and move underwater

completely independently. Since pool geometries are

usually simple, navigation logic can also be kept sim-

ple. Simple sensor arrays on the fronts and backs of

these systems are the elements of an efﬁcient cleaning

strategy.

Pool cleaning robots must be lightweight to make

operator handling easy and to attain sufﬁcient buoyancy

for retrieval. Hence, battery operation is often not an

option since it would not allow the necessary clean-

ing performance. Such systems are supplied with power

through a cable with which they can be retrieved in the

event of damage.

Ventilation Duct

and Sewer Line Cleaning Robots

Cleaning systems for pipes, sewers, and ducts represent

a sizeable market since their inaccessibility often pre-

vents humans from being able to clean them without

cleaning automation. Pipe and ventilation duct diam-

eters are too small or areas may be hazardous to health

or potentially explosive, e.g., in the petroleum industry

or sewage disposal.

Thousands of different systems for pipe, ducts, and

sewer line cleaning exist all over the world. As a rule,

they are remote controlled or semiautomatic and move

on wheels or tracks. They normally do not navigate

autonomously and incorporate video cameras to dis-

play their environment to the operator. A cable connects

these systems to a supply and control station. While

this limits the systems’ radius of action, it assures they

are highly reliable, are supplied cleaning medium and

can be recovered from pipes, sewers, and ducts with

certainty. Cleaning methods vary widely depending on

the case of application and include brushes, water, high

water pressure, and dry ice.

70.2 Examples of Application

The automatic systems presented here are established

systems that have achieved product maturity and, for

the most part, been in operation for years. In addi-

tion to special applications for which very few systems

are available worldwide, there are also applications for

which a mass market has already opened. Accordingly,

the systems cited here merely represent a few exam-

ples of the wide range of cleaning automation products.

Space constraints only allow the description of cleaning

systems presently in operation and preclude covering

the multitude of prototype developments and experi-

mental models.

70.2.1 Floor Cleaning Systems

A distinction must be made between professional and

household ﬂoor cleaning systems as well as the types of

cleaning, i.e., vacuuming and wet cleaning. The Hefter

ST82 R ﬂoor washing robot is an example of profes-

sional wet cleaning, and iRobot’s Roomba of household

vacuuming. While the technical conﬁguration and per-

formance of other manufacturer’s systems differ, the

basic concept is comparable.

ST82 R Floor Washing Robot

Manufacturer: HEFTER Cleantech GmbH,

Germany

Type: Professional ﬂoor cleaning

system

Operating mode: Autonomous, taught path

Cleaning technology: Wet cleaning

Area of application: Supermarkets, airports, large

halls, etc.

Based on a standard ﬂoor cleaning system, the

Hefter ST82 R ﬂoor washing robot is intended for

professional cleaning of hard ﬂoors (Fig.70.2). Outﬁt-

ted with auxiliary localization and collision avoidance

sensor systems, a navigation system and an onboard

computer, the Hefter ST82 R is able to follow and ef-

fectively clean a programmed path fully autonomously

and independently of an operator [70.5].

This cleaning robot can run in two operating modes:

manual and automatic. In manual mode, the system per-

forms like a hand-guided ﬂoor cleaning system in order

to teach it the path to be cleaned autonomously and to

recover it in the event it malfunctions.

Part G 70.2

Cleaning Automation 70.2 Examples of Application 1257

Fig. 70.2 Hefter cleaning robot ST82R

Automatic mode is programmed in two stages. The

robot’s entire work space is ﬁrst navigated in manual

mode. The robot’s onboard navigation software auto-

matically generates a virtual map of the workspace

from the data collected by an odometer, a gyrocom-

pass, ultrasonic sensors, and laser scanners during the

ﬁrst reference run.

A second reference run is taken afterward. This

time, the intended cleaning route is followed exactly.

A cleaning path based on the sensor data is entered into

the virtual map. A Siemens SINAS navigation system

furnishes the necessary navigation intelligence [70.6].

Once the reference runs have been completed, the

cleaning robot is able to navigate the programmed path

on its own. To do so, the robot is switched to auto-

matic mode. The operator can no longer intervene in

the robot’s movement in automatic mode.

Since the robot moves in peopled surroundings,

a multitudeof safety mechanisms that preventcollisions

with and injuries to people have been provided.

Along with switching strips mounted all over the

robot, a laser scanner installed in the front skirt is an

integral element of the safety concept. If one of the

safety systems is activated, the robot initially reacts by

moving to evade the direction of the source of activa-

tion. If this does not cancel the activated safety system,

then an emergency stop is triggered. Automatic opera-

tion can be resumed only after acknowledgement by an

authorized operator.

In hazardous situations the safety system is unable

to detect, automatic operation can be interrupted by ac-

tivating emergency stop buttons on the robot.

The Hefter ST82 R ﬂoor washing robot system was

successfully tested in various retail stores but is no

longer available for purchase.

Floor cleaning robots from other manufacturers in-

clude:

•

The Hako Acromatic is for autonomous profes-

sional cleaning in buildings (but is no longer

sold) [70.7].

•

Fuji Heavy Industries’ Subaru RFS1 is the succes-

sor to an autonomous ﬂoor cleaner sold since 2000.

The latest model communicates with the elevator

and canthus move independently from ﬂoorto ﬂoor.

It is not designed for manual operation [70.8].

Other systems that at least deserve brief mention

are the Comac CLEAN [70.9], Cybernetix Auror and

Baror [70.10], Thomson Abilix 500 [70.3], Servus

Robots [70.11], CleanFix Robo40 [70.12], Floor-

botics [70.13], Robosoft AutoVac C6 and C100 [70.14],

and VonSchrader Dolphin [70.15], AUTOMAX AXV-

01 [70.16].

Roomba 500 Series Vacuum Cleaning Robot

Manufacturer: iRobot Corporation, USA

Type: Household vacuum cleaning

system

Operating mode: Autonomous

Cleaning technology: Vacuum cleaning

Area of application: Standard rooms in homes.

Vacuum cleaning is one of the few ﬁelds of applica-

tion for which a mass market has already opened for

service robots in general and cleaning robots in par-

ticular. The most successful system in this segment is

iRobot’s Roomba robot (Fig. 70.1), which consists of

a cleaning robot and a base station. The circular clean-

ing robot stands atop three wheels, of which two are

drive wheels and one a caster wheel, and navigates an

unfamiliar environment completely autonomously. Es-

sentially, the robot operates automatically [70.17].

In principle, it cleans on the basis of a classical

vacuum cleaner with a powerful vacuuming unit and ro-

tating brushes conﬁgured so that even dirt in the robot’s

boundary area is picked up. A dirt detecting sensor is

located in the suction zone.

The path being cleaned does not have to be pro-

grammed. Equipped with optical ranging sensors and

contact sensors, the system detects when it nears an

obstacle, proceeds toward it at reduced speed, and

changes its path direction upon contact. Ranging sen-

sors directed downward detect stairs and drop-offs and

generate a change of path direction as well.

Path direction is not changed randomly. The robot

utilizes sensor data to analyze its environment and se-

Part G 70.2

1258 Part G Infrastructure and Service Automation

lects one of four motion patterns depending on the

situation: spiraling, wall following, room crossing, and

dirt detection.

Dirt detection is selected whenever larger quantities

of dirt are detected in the suction ﬂow. The robot reacts

by increasing suction power and follows a spiral motion

pattern until the quantity of dirt drops again.

Virtual walls can be used to limit the robot’s

workspace. These are generated by stations which emit

an infrared beam. If its battery charge drops below

a critical value or it has ﬁnished cleaning, the system

returns on its own to its base station, which emits an

infrared beam that acts as a guide beam for the robot.

Systems from other manufacturers include:

•

The Kärcher RC3000 (Germany) is an autonomous

vacuuming robot for household use (largely similar

in design to the Siemens VSR8000). It is the only

household appliance that disposes of collected dirt

in its docking station [70.18].

•

The Inﬁnuvo Cleanmate QQ2 is an autonomous

vacuuming robot for household use. It additionally

kills germs with an ultraviolet (UV) lamp and fresh-

ens air with fragrance capsules [70.19].

•

The iRobot Scooba (USA) is Roomba’s successor

that not only vacuums but also wet mops [70.17].

•

The Electrolux Trilobite (Sweden) was introduced

as the ﬁrst vacuuming robot for household use in

2001 [70.2].

Other systems that at least deserve brief mention

are the LG RoboKing, Hanool Ottoro, Black&Decker

ZoomBot, and Sharper Image eVac.

70.2.2 Roofs and Facades

A number of facade cleaning robots have moved well

beyond the research and prototype stage and are being

operated as special developments exclusively on spe-

ciﬁc facades. Since relatively little time and effort is

required to adapt remote-controlled systems, they will

quite likely be used on other facades in the near future.

Filius Glass Roof Cleaning Robot

Developer: Fraunhofer IFF, Germany

Type: Professional roof cleaning

system

Operating mode: Remote controlled

Cleaning technology: Wet roof cleaning

Area of application: Berlin Central Train Station,

Germany.

Fig. 70.3 Fraunhofer IFF Filius roof cleaning robot

The Fraunhofer IFF specially developed a remote-

controlled cleaning robot for Berlin central train station

in Germany (Fig.70.3). However, it can also be used

on other roofs with comparable geometries once the

appropriate infrastructure has been installed.

Filius is a remote-controlled, semiautomatic robot

that can navigate obstacles with heights of up to

200mm. Onboard cable winches secure Filius to

a gantry on the roof ridge from which it is supplied with

power and water through a cable and a hose. As clean-

ing progresses, the gantry moves incrementally so it is

always located above the robot.

Dirt is loosened by a rotating brush mounted on the

front, and is then rinsed away by a nozzle bank behind

the brush. An operator assumes the control of action

functions such as path direction and brush activity by

remote control.

Wobble sticks and ultrasonic sensors detect travel

across the roof surface and an emergency stop prevents

operators from driving the robot over the roof’s edge.

Its all-wheel drive makes the robot extremely ma-

neuverable on all terrain. Ramps laid out enable it to

navigate the gantry’s rails and expansion joints between

individualroof areasfor instance.Thus, therobot can be

positioned and used on the entire surface of the station’s

roof.

Feeder lines on the roof,fed with high-pressure soft-

ened water by a supply vehicle, supply water to the

gantry.

RobuGlass Glass Roof Cleaning Robot

Manufacturer: Robosoft, France

Type: Professional roof cleaning

system

Operating mode: Remote controlled

Cleaning technology: Wet roof cleaning

Area of application: Louvre Pyramid (France).

Part G 70.2

Cleaning Automation 70.2 Examples of Application 1259

A remote-controlled robot cleans the glass Lou-

vre Pyramid in Paris, France. Combining suction and

caterpillar tracks, the robot travels up and down the

triangular surfaces. The absence of any overhead se-

curing device is a special feature of the Louvre robot.

Technically, it is designed so that the frictional force

of the walking mechanism sufﬁces to prevent it from

sliding down the sloping surface in the event of a mal-

function. Operators at the foot of the pyramid supply it

from below through cable and hose, the compressed air

needed being provided by equipment located on a sup-

ply vehicle. Rotating brushes do the cleaning and a car

windshield wiper dries the path of travel during down-

ward travel [70.20].

Compared with other facade cleaning robots, the

Louvre system has a very simple design. The mini-

mum of distinctive features of the facade substantially

reduces complexity. First, the triangular surfaces are

completely level, only interrupted by silicone joints.

Consequently, a very simple walking mechanism can

be used since there are no obstacles to be navi-

gated. Second, the system cannot fall when it travels

across the sloping surfaces, thus making an over-

head securing device unnecessary. Safety engineering

accounts for a large part of other facade cleaning

robots’ systems and weight. Third, the sloping smooth

surfaces allow water from cleaning to simply run

off. This simpliﬁes the cleaning system. Fourth, the

space around the pyramid is navigable by a vehi-

cle and the system can be recovered with a small

crane at any time. Its relatively short cleaning paths

enable supplying the robot from below. The requi-

site cables and hoses are simply pulled along the

glass.

Glass Roof Cleaning Robot

for Leipzig’s New Exhibition Center

Developer: Fraunhofer IFF, Germany

Type: Professional roof cleaning

system

Operating mode: Autonomous

Cleaning technology: Wet roof cleaning

Area of application: Entrance hall of Leipzig’s new

exhibition center (Germany).

Two fully automatic cleaning robots have been

cleaning the 25000m

glass hall of Leipzig’s new ex-

hibition center in Germany since 1997 (Fig. 70.4). The

roof consists of a glass facade suspended from a steel

structure. Accessing it with a gantry alone or other ac-

cess equipment would be extremely complicated.

Fig. 70.4 Fraunhofer IFF cleaning robot in Leipzig

A gantry transports the robots along the roof ridge

and uses small hoists to lower them onto the glass sur-

face between the pane mounts. The robots then move

downward under the steel trusses and between the

mounts, cleaning the glass. Upon returning to the top,

the robots are picked up by the hoists and shifted to the

next path. A broad roller brush cleans the entire surface

of the facade lane by lane, starting at the eastern end of

the roof and ending at the western end. Since the robots

are unable to move around the mounts, these areas are

cleaned by disc brushes on retractable arms. Chemical-

free deionizedwater is sprayedonto the glass to moisten

and wash away dirt mobilized by the brushes.

The gantry on the roof ridge secures each cleaning

robot with two Dyneema ropes and supplies each with

power and water through its own cable and hose. To

prevent damaging the panes of glass and silicone seals,

hose, cable, and securing ropes are coiled and uncoiled

inside a robot and thus laid down on the glass instead

of being dragged over it. Furthermore, since the bearing

wheels are not driven, the two securing ropes are used

to correct the robot’s direction of travel. A ﬁfth wheel

only provides the necessary drive in ﬂat areas.

The steel structure limits the size a robot may have.

At an overhead clearance of 38cm, the robot’s height is

just 30cm. The travel path is 45 m long and runs from

the ridge between the pane mounts down into the eaves.

The distance between mounts limits the robot’s width

to 1.5m.

Part G 70.2

1260 Part G Infrastructure and Service Automation

Odometer measurements of the distance covered by

two wheels are supplemented by eddy-current sensor

measurements of the distance covered using the mounts

as reference marks. In addition, the distance to the

mounts to the robot’s left and right is used to correct

path direction, controlled by adjusting the coiling of the

two ropes. Expansion of the hall due to heat as well as

the general tolerances of the mounts’ uniformity make

navigation between mounts more challenging.

The gantry and robots move fully automatically

and are monitored from a master control room where

exact positions and actions are displayed. The robots

also accept abstract commands from a manual control

menu [70.21,22].

CleanAnt Glass Facade Cleaning Robot

Manufacturer: Niederberger, Switzerland

Type: Professional facade cleaning

system

Operating mode: Autonomous

Cleaning technology: Wet facade cleaning.

Consisting of two limbs with suction cups attached

to both ends, CleanAnt constitutes a walking kinematics

with ﬁve degrees of freedom (Fig.70.5). While one foot

is ﬁxed on a pane, the second swings into the next walk-

ing position or moves over the surface to clean a pane.

A control computer synchronously controls and posi-

tions the axles, inverse kinematics identical to industrial

robot controls determining the positions of the joints.

Fig. 70.5 CleanAnt climbing robot

However, its base coordinate system changes when the

ﬁxed foot changes.

The system automatically holds itself on the facade

being cleaned, thus making it possible to clean vertical,

overhanging or even curved facades. A slack rope se-

cures the cleaning system and only goes taut should the

system fall, thus preventing it from falling entirely.

Transceiver units on the building’s corners, which

triangulate current position, monitor its position on

a surface. The surface being cleaned is modeled in

computer-aided design (CAD) and uploaded to the

robot control system. The robot then follows a prede-

ﬁned motion path autonomously.

While the complicated walking pattern, the few de-

grees of freedom, and the limited size of the cleaning

unit prevent the system from covering large areas, it

still qualiﬁes as a service robot since it is able to clean

surfaces that would otherwise be inaccessible, i.e., it

can easily clean vaulted surfaces. Moreover, CleanAnt

can move around corners or from wall to ceiling and

navigate larger recesses or obstacles.

Wet brush cleaning and semidry cleaning with

ﬂeece or dry ice can be applied as cleaning technolo-

gies. A hose supplies the requisite media from above

or below. For special operations, CleanAnt can also be

deposited onto a facade manually, e.g., from a gon-

dola, and maneuvered into speciﬁc areas by remote

control.

While it is marketed for professional facade clean-

ing, CleanAnt is the only robot cited here that is not

yet in operation. Nonetheless, it deserves mention if

only because its design representssuch agreat departure

from conventional robots [70.1,23].

Fig. 70.6 SIRIUSc facade cleaning robot for automatic

cleaning of high-rise buildings

Part G 70.2

Cleaning Automation 70.2 Examples of Application 1261

Other facade cleaning robots include:

•

The Fraunhofer IFF’s SIRIUSc cleaning the vertical

facades of the Fraunhofer-Gesellschaft’s headquar-

ters in Munich, Germany (Fig. 70.6) [70.22,24,25]

and

•

Beihang University’s SkyCleaner III in operation on

the Shanghai Science and Technology Museum in

China [70.26].

70.2.3 Ducts and Sewer Lines

Regular cleaning of sewer lines isa basic measure toen-

sure they operate reliably. Cleaning of ventilation ducts

on the other hand is not essential to operational relia-

bility but arguably to protect people’s health. Although

sewer lines and ventilation ducts have similar geometric

properties, the boundary conditions for cleaning robot

operations differ fundamentally. Two systems serve as

examples of ventilation duct and sewer line cleaning

respectively.

Multipurpose Duct Cleaning Robot

Manufacturer: Danduct Clean, Danmark

Type: Professional duct cleaning sys-

tem

Operating mode: Remote controlled

Cleaning technology: Brushes, dry-ice cleaning

The Danish company Danduct Clean’s multipurpose

robot is a universal system that cleans and inspects ven-

tilation ducts. An all-wheel drive robot platform serves

as the carrier system. The overall system does not have

any collision sensors. However, two cameras directed

toward the front and the rear relay a direct impression

of the robot’s environment. The carrier system is out-

ﬁtted with different cleaning systems depending on the

case of application.

Rotating brushes are used in dry ventilation ducts

to remove dust clinging to the walls. Various brush

systems are available depending on the duct geome-

try. A dry-ice cleaning system is employed in exhaust

areas of kitchens and the like where sizeable grease de-

posits form in ventilation ducts. Temperatures as low as

−79

◦

C facilitate their removal.

Irrespective of thecleaning systemused, cableswith

lengths of up to 30m supply media and transmit data to

an external control box. The robot is controlled from

the control box by joystick based on camera feedback.

Cruise control is additionallyavailable for long, straight

duct sections.

To effectively remove loosened dirt, inﬂatable

balloons seal off the duct section being cleaned. A pow-

erful suction unit is hooked up to the duct opening in

the direction of work and extracts loosened dirt from

the duct [70.27].

Other duct cleaning robots are manufactured by:

•

Indoor EnvironmentalSolutions, Inc.(USA) [70.28]

•

DRY ICE Engineering GmbH (Germany) [70.29]

•

HANLIM MECHATRONICS(South Korea)[70.30].

Sewer Cleaning Robot

Developer: Fraunhofer IFF, Germany

Type: Professional sewer cleaning

system

Operating mode: Automatic

Cleaning technology: High pressure.

Isolated sewer cleaning robots exist for inaccessible

sewer lines. Some remote-controlled inspection robots

for small sewer line diameters can be outﬁtted with

high-pressure nozzles. As a rule, however, small sewer

lines are cleaned with cleaning nozzles that utilize high-

pressure water for propulsion.

Contracted by the Emschergenossenschaft in Ger-

many, the Fraunhofer IFF developed a fully automatic

cleaning robot for sewer lines with diameters of

1600–2800 mm. The system employs an ejector nozzle

to mobilize deposits that are underwater and high-

pressure water to clean the pipe wallabovethe waterline

in sewer lines that are 20–40% full at all times. The

system can clean sewers up to 750m in length. The

wheel-driven cleaning system is roughly 4m long and

weighs 2.5t.Anultrasonic scanner monitors the clean-

ing results underwater and a camera monitors the area

above water. A specially equipped vehicle on the street

level supplies the cleaning system with up to 250l

of water per minute over a distance of up to 750m

with a nozzle pressure of over 100bar. The clean-

ing system dependably navigates in the sewer line and

system recovery is ensured through the cable connec-

tion [70.22,31].

70.2.4 Swimming Pools

Swimming pools accumulate large quantities of dirt

on a daily basis. The relatively large surfaces gather

dirt out of the air and off swimmers. Public swim-

ming pools are subject to hygiene codes with strict

water quality limit values that necessitate regularly

cleaning the bottom and walls of a pool. Underwa-

Part G 70.2

1262 Part G Infrastructure and Service Automation

Fig. 70.7 WEDA B680 pool cleaning robot

ter cleaning machines have been in use since the

1970s. Such pool cleaners qualify as service robots

since they move and systematically navigate pools au-

tonomously. While the various manufacturers’ systems

share virtually the same robot engineering concept,

their designs, target markets, and cleaning systems

differ.

B680 Pool Cleaning Robot

Manufacturer: Weda, Sweden

Type: Professional pool cleaningdiffer

system

Operating mode: Autonomous, remote controlled

Cleaning technology: Brushes, water ﬁlter system.

The base of Weda’s B680 pool cleaning robot is

a tracked vehicle maneuverable by separately control-

ling its left and right track (Fig.70.7). Its forward speed

is approximately 0.25m/s. A water pump suctions in

approximately 1200l of water per minute on the un-

derside and rinses it through a reusable particle ﬁlter.

Common systems for residential use only manage ap-

proximately 250l/min. The suction generated beneath

the system is sufﬁcient to enable the pool cleaner to tra-

verse vertical walls underwater. Rotating brushes loosen

dirt particles in front of and behind the unit, moving

them in the direction of the suction opening. Power is

supplied by a cable connected to a base station on the

edge of the pool. It is uncoiled and ﬂoats on the surface

during cleaning.

The robot is internally balanced in such a way that

it glides gently downward and lands on its feet when

loweredinto a pool or when it detachesfrom a side wall.

Electronics in the B680 were kept to a minimum so

that the unit is as easy for users to understand as possi-

ble. Contact sensors to the front and rear of the robot are

used for navigation and reverse the drive directionwhen

pressed. The unit has a slightly oblique front bumper

that generatesthe slight change in direction when it con-

tacts a pool wall. As a result, it reaches the opposite end

of itspath onits return travelsomewhatoffset.This sim-

ple navigation technique enables the complete cleaning

of rectangular pool surfaces quicker than through ran-

dom motion.

A pool cleaner is placed in the water during a pool’s

off hours and activates itself with a time switch after

a short wait, by which time the water has calmed and

dirt particles have settled. The cleaning is ﬁnished in

a few hours and the unit deactivates itself for retrieval

from the water the next morning. Control keys execute

the requisite maneuver. The ﬁlter bag size is dependent

upon its planned hours of operation. If it is too small, it

clogs quickly, thus diminishing cleaning performance.

In such a case, the cleaning robot would merely be em-

barking on a joyride and would lose traction as suction

decreases [70.32].

Other manufacturers of professional and household

pool cleaning systems include:

•

Maytronics’ (Israel) pool robots are intended for

residential use and smaller pools. Maytronics

offers the only battery-powered robot. Maytron-

ics products are marketed globally under various

names [70.33].

•

iRobot (USA) offers several models that suction up

and ﬁlter dirt in water [70.17].

•

Aquatools (USA) offers robots for residential use

and smaller public pools.

•

Mariner 3S (Switzerland) sells professional pool

cleaners. Instead of collecting bags, some units use

ﬁlter cartridges that are cleaned afterward with aux-

iliary equipment [70.34].

Part G 70.2

Cleaning Automation References 1263

70.3 Emerging Trends

Especially in the domain of cleaning, service robots

already provide many different options for relieving

people of dangerous, stressful, and/ormonotonous work

and are penetrating both household and professional

market sectors. Household systems have technically

simple and low-cost designs and are already being sold

in large numbers. Professional systems are technically

complex, ﬂexible, cost effective, efﬁcient, and easy to

operate. However, since they fail to fulﬁll the requi-

site criteria in many cases, they have not yet established

themselves as mass products. Nevertheless, numerous

individual solutions exist for special applications such

as facade or pool cleaning.

To the extent that they do not fully navigate

surfaces whengeometries are more complex or environ-

ments are dynamic and generally can neither navigate

themselves nor coordinate tools better than humans,

professional cleaning robots’ sensory and cognitive

capabilities continue to limit their universal and cost-

effective use.

Such cleaning robots will not become mass prod-

ucts until their cost effectiveness, performance, ef-

ﬁciency, and total attendant costs make them su-

perior to manual cleaning. Further development of

service robots’ cognitive capabilities, environment

modeling sensor systems, and multimodal user in-

terfaces is being pursued worldwide for other ﬁelds

of application and is a fundamental prerequisite to

establishing cleaning robots in the professional sec-

tor.

References

70.1 R.D. Schraft: Service Robots (B&T, Munich 2000)

70.2 IFR: World Robotics Report 2006 (International Fed-

eration of Robotics IFR, 2006),

www.worldrobotics.com, last cited 2009

70.3 E. Prassler, A. Ritter, C. Schaefer, P. Fiorini: A short

history of cleaning robots, Auton. Robot. 9, 211–226

(2000)

70.4 S. Hirose, K. Kawabe: Ceiling walk climbing robot

Ninja-II, 1st Int. Symp. Mobile, Climb. Walk. Robots

(Brussels 1998) pp. 143–147

70.5 U. Zechbauer: Der elektronische Saubermann, Pict.

Future (Herbst), 59–61 (2002), in German

70.6 G. Lawitzky: A navigation system for cleaning

robots, Auton. Robot. 9(3), 255–260 (2000)

70.7 M. Schoﬁeld: Neither master nor slave, 7th Int.

Conf. Emerg. Technol. Fact. Autom., Vol. 2 (IEEE,

Piscataway 1999) p. 1427

70.8 H. Aoyama: Building cleaning robot system, 1st

German-Japanese Summit Mobile Auton. Syst.

(Hannovermesse 2008)

70.9 Comac: Verona, Italy (2008) www.comac.it

70.10 Cybernetix: Marseille, France (2008)

www.cybernetix.fr/

70.11 Intellibot: Pittsburgh, USA (2008)

www.intellibotrobotics.com

70.12 Cleanﬁx: Cleaning Systems, Wyckoff, ISA (2008)

www.cleanﬁxusa.com/cleanﬁx-site/robo40.php

70.13 Floorbotics: Northcote, VIC, AUS (2008)

www.ﬂoorbot.com/

70.14 Robosoft Advanced Robotics Solutions, Bidart,

France (2008), www.robosoft.fr

70.15 Von Schrader: Racine, USA (2008)

www.vonschrader.com/equipment/carpet/

dolphin/dolphin.htm

70.16 The Speciﬁcations and Applications of Robots in

Japan – Non-Manufacturing Fields (Japan Robot

Association, Tokyo 1997) pp. 328–329

70.17 iRobot: Roomba (iRobot, Bedford 2008),

www.irobot.com

70.18 Kärcher: Winnenden, Germany (2008)

www.karcher.com

70.19 Inﬁnuvo: San Jose (2009) www.inﬁnuvo.com/

70.20 A. Kochan: Robot cleans glass roof of louvre pyra-

mid, Ind. Robot 32, 380–382 (2005)

70.21 N. Elkmann, U. Schmucker, T. Boehme, M. Sack:

Service robots for facade cleaning, advanced

robotics: Beyond 2000, 29th Int. Symp. Robot.

(Birmingham 1998) pp. 373–377

70.22 Fraunhofer IFF: Magdeburg, Germany (2008)

www.iff.fraunhofer.de/en/robotersysteme.htm

70.23 Serbot: Oberdorf, Switzerland

www.serbot.ndswing05.ch/ (2009)

70.24 N. Elkmann, D. Kunst, T. Krueger, M. Lucke,

T. Boehme, T. Felsch, T. Stuerze: SIRIUSc – facade

cleaning robot for a high-rise building in Mu-

nich, Germany, Proc. 7th Int. Conf. CLAWAR 2004

(Springer, 2004) pp. 1033–1040

70.25 N. Elkmann, D. Kunst, T. Krueger, M. Lucke,

T. Stuerze: SIRIUSc: fully automatic facade cleaning

robot for a high-rise building in Munich, Ger-

many, Proc. Jt. Conf. Robot. ISR 2006/Robotik 2006

(Munich 2006) pp. 203–204

70.26 H.Zhang,J.Zhang,W.Wang,R.Liu,G.Zong:Sky

cleaner 3 – a real pneumatic climbing robot for

glass-wall cleaning, IEEE Robot. Autom. Mag. 13(1),

32–41 (2006)

70.27 Danduct Clean: Herning, Denmark (2008)

www.danduct.com

Part G 70

1264 Part G Infrastructure and Service Automation

70.28 Indoor Environmental Solution: Houston, USA

(2008) www.cleanducts.com/

70.29 Dry Ice Engineering: Mainhausen, Germany (2008)

www.dryiceclean.de

70.30 Hanlim Mechatronics: Gyungki-Do, Korea (2008)

www.ductrobot.co.kr/en/page2.html

70.31 N. Elkmann, H. Althoff, S. Kutzner, J. Saenz,

T. Stuerze, C. Walter, E. Schulenburg: Automated

inspection system for large underground concrete

pipes partially ﬁlled with waste water, Proc. Jt.

Conf. Robot. ISR 2006/Robotik 2006 (Munich 2006)

pp. 167–168

70.32 Weda: Södertälje, Sweden (2008) www.weda.se

70.33 Maytronics: Yizreel, Israel (2008)

www.maytronics.com

70.34 3S Systemtechnik: Remigen, Switzerland (2008)

www.mariner-3s.com

Part G 70