|Title of Invention||
METHOD FOR APPLYING PAINTS AND VARNISHES
|Abstract||The invention relates to a method for applying paints or varnishes with the aid of an application device in order to apply a color design on surfaces of buildings or public or civil engineering works in accordance with a previously executed implementation of a digital image model in a previously recorded digital surface object that represents the surface of the object. According to the invention, the application device moves on the surface of the object while contacting the surface thereof, the position of the application device is continuously measured or calculated using motion sensors and paint is applied in accordance with said implementation depending on the position thus determined. Application of paint by the application device is automatically stopped if the position of the application device with respect to a predefined position error acceptance threshhold cannot be determined in a sufficiently accurate manner or if the corresponding paint or varnish has been fully applied in the position of the paint applying elements.|
|Full Text||METHOD FOR APPLYING PAINTS OR VARNISHES
The invention relates to a method and device for the application of paints or varnishes in order
to color the object faces of objects like buildings and public and civil engineering works
according to an image template. These can be object faces for example of inside or outside
walls, floors and ceilings of residential or industrial buildings, but also object faces out of
concrete like bridges, tunnels and road construction works or walls for noise protection,
blinds or fixations or to surfaces of related species.
Today the afore mentioned object faces are without exception painted manually by paintbrush
or paint roller or are color-sprayed using an airgun. The paint serves for sealing purposes of
the wall on the one hand, but it is also utilized for decoration purposes. If image themes are to
be applied onto the mentioned surfaces by paint the paint application can only be performed
by talented craftspeople or artists, a process which is normally tedious and thus expensive.
Often there can be an essential dicrepancy between the expectations of the client and the
finalized image. A pure technical method would be desirable, which makes it possible to
apply an image theme according to a template onto the mentioned surfaces by using paints or
varnishes without requiring artistic skills and which additionally ensures a high quality of
image recording. So it is obvious, that a method and a device do not exist, which allow for
example to apply a color design according to a digital template onto surfaces of architectural
objects like buildings and public and civil engineering works.
Based on that fact it is the task of the invention to create a simple and fast, thereby a
costeffective as well as reliable method to apply paints or varnishes onto foremost
architectural object surfaces, with the purpose to apply an arbitrary color design.
The technical solution is characterized as in claim 1.
According to claim 1 the application device is brought into contact with the surface and is
moved arbitrarily on the surface. The application device measures its position continuously by
use of a non-contact positioning system or additional motion sensors and it applies paint
depending on the position measured in accordance with said implementation. In doing so the
application device stops the application of paint automatically, if its position with respect to a
predetermined position error acceptance threshold cannot be determined sufficiently accurate
or paint has already been fully applied in the position of the paint applying elements.
By this a fast and reliable method is created, by which it is possible, to apply existing digital
image data onto arbitrary faces of objects like buildings and public and civil engineering
works. The herewith claimed method allows the operator of the paint application device to
work intuitively by moving the device in an arbitrary sequence over arbitrary positions of the
object face. This intuitive way of operation especially enables to paint the surface completely,
also around protrusions, balconies, doors, windows, sills or cornices.
The method according to the invention is based on the thought to transfer the color
information of every image pixel, which was previously stored into a file, to the objetct
surface, by measuring the position of the paint application device continously and by applying
paint after having compared the stored color information with the corresponding position of
the paint application device. To apply a color design according to the method of the invention,
it is a prerequisite that the object face has been recorded previously by using measurement
techniques, resulting in a digital object, which is for example a CAD- representation of the
surface, and that next to this a template of the desired design object has been implemented
according to the designer's wishes, i.e., there is a geometric assignment of the color data to
the real positions of the object face available, see Fig. 1. Color properties of the original
object surface could have been implemented as well, if having been recorded additionally,
thus making it possible to include existing color features into the design or to compensate
unwanted color features like spots on the surface.
When the movable paint application device is moved over the object face, the position
measurement system continuously supplies the actual position. Due to the known position of
each single paint application element within the design of the device and the known position
of the paint application device relative to the object face the position of every paint
application element is computed in realtime. The control unit then fetches the color values
from the surface object, which is stored in the system memory as assigned to the position-
coordinates, and sends exactly timed commands for color application to the individual paint
nozzles. Once a virtual color pixel has been fully applied onto the object face the pixel is, for
example, assigned the attribute "done", switched passive or the color value is pasted by a
value, which does not result in a color application. By this an unintended multiple color
application at a single point can be avoided.
At least once every point of object face has to be passed over by the application head during
paint application. Thanks to the integrated position calculation a countinous motion of the
device is not required, because at any time the device compares the actual position with
respect to the stored image to be recorded and commands for paint application are only
launched, if paint has to be applied at that position, and has not already been finalized by an
earlier stroke of the device.
The position measurement of the paint application device can be done in multiple ways by use
of position measurement systems, see also the system chart in Fig. 2. These may be devided
into two cathegories:
The systems herein referred to as first measurement system measure the position of movable
components in relation to fixed landmarks, herein called satellites, also as part as of the first
measurement system. The movable parts of the first measurement system can be included into
the paint application device. It is a characteristic of the first measurement system, that there
has to be an intervisibility between the satellites and the moving components. Intervisibility
can be often disturbed, for example by scaffoldings, cornices or branches, and position
sensing is interrupted.
The systems herein referred to as second measurement system measure the motion of the
paint application device for example by sensors, which are included in the paint application
device and which do not utilize fixed landmarks. These are for example linear and rotational
acceleration sensors, rotational rate sensors, velocity sensors, magnetometers, inclinometers,
and imaging sensors, which inspect a small area of the object face, from which the motion is
calculated for example by correlation methods. The measurement methods of the second
measurement system are further characterized in being fast, being not able to sense an
absolute position and being sensitiv to drift.
The accuracy requirements of the position sensing are high: When assuming an absolute
image resulution of 0.5 mm in a range of 10 meters a realtive accuracy of 50 ppm is resulting.
In parallel it is required, that the paint application device can be moved sufficiantly fast at any
point of the object face and thereby being always able to measure its position with the
Some measurement methods according to the first measurement system can only provide a
low measurement rate. So, position information is not permanently available, also and
especially in case of disturbed intervisibility between satellites and the movable components.
On the other hand the much faster methods as used in the second measurement system are
suited to overtake navigation for short time periods. It is obvious, that combining both allows
for covering the object face completely on the one hand and allows for a high feed rate on the
Assuming a paint application device operated manually by an operator the device control acts
as follows, see Fig. 10:
The operator brings the paint application device into contact with the object surface by
pressing it against the surface. When the color application is started by a command from the
operator, it is checked first if position informations are available from the first measurement
system. For this intervisiblity has to be possile between the relevant components of the first
measurements system. If not, the operator has to be informed, either by a negative message or
by not providing a positive message, and the operator is instructed to move the paint
application device over the surface, until the first measurement system supplies a valid
position. This position is used by the paint application control and to initialize the second
measurement system. Initializing can simply mean to reset the initial conditions of the motion
sensors. Now follows the computation of the position based on the available measurement
data as provided from the first and the second measurement system. In this case, right after an
initialization, the position calculated is identical to the position provided from the first
measurement system. A positioning error is estimated and handed over to a range check
routine to get a decesion, whether paint may be applied or not. If the position error exceeds an
accepatance threshhold, the color application is stopped and the afore described process of
finding an initial position has to be repeated. Typically, the estimated position error does not
exceed the acceptance threshhold, so paint application can be performed and new position
data can be read. The described cycle is running so fast, that the paint application device has
already moved due to the velocity of the motion. So a position error is produced due to said
motion and furthermore by the fact, that every paint application head induces a definite time
delay when transporting the paint onto the surface. As a consequence the resulting position
error has to be corrected for example by implementing position offsets. Practically this means,
that those color values of the color - position assignment are forwarded to the color
application head for paint application, which according to the color - position assignment are
located ahead of the actual realtime position. The position offset generally is a function of the
velocity and the acceleration. It is recommended to additionaly evaluate and check the
acceleration of the device before applying paint in order to automatically prevent paint
application during jerkey motions. After having applied paint, the first measurement system is
checked for a valid position. A position may by invalid, if intervisibility is disturbed, as
already explained above, or if the measurement rate of the first measurement system is lower
than the actual cycle speed of system. If there are new data available from the first
measurement system, the calculation of the actual position may be based on actual position
data as well as past position data. If not, a message will be sent to the operator and the
subsequent position calculation will only be based on actual measurement data from the
second measurement system and past position information. In both cases the position error is
evaluated and checked before issuing the paint application command. It is obvious, that when
moving the paint application device far into an area, where intervisibility fails, the position
error increases from cycle to cycle and finally the paint application is stopped automatically.
Based on the messages the operator is able to recognize regions, where intervisibility issues
within the first measurement system occur. If he has identified an aforesaid region, he is
advised to bring the paint application device into contact with the object face at a point of
known position and to move the device into the said region shortest or quickest path. In case
of a very large reagion, when also repeated action does not result in a paint application, the
opertator is advised to mount additional landmarks of the first measurement system.
List of figures:
Fig. 1: Preparatory work
Fig. 2: Complete system
Fig. 3: Paint application head
Fig. 4: Extended paint application head
Fig. 5: First embodiment of the first measurement system
Fig. 6: Second embodiment of the first measurement system
Fig. 7: Landmark
Fig. 8: Third embodiment of the first measurement system
Fig. 9: Embodiment of a paint application system using a measurement system according to
Fig 10: Control strategy
Fig. 11: and Fig. 12: First embodiment of the paint application device
Fig. 13: Second embodiment of the paint application device
Fig. 14: Third embodiment of the paint application device
Fig. 15: Paint application nozzle distance control
Fig. 16: Paint application using the paint application device according to Fig. 14
Fig. 17: Facade painting system using a cable feed
Fig. 18: Autarc robotic system
At the beginning of the work procedure the satellites as a subsystem of the first measurement
system, see embodiments Fig. 2, Fig. 5, Fig. 6, Fig. 8, are mounted by the operator at fix
positions. They define the reference coordinate system. For the functionality of the first
measurement system it is necessary, that intervisbility is established between the paint
application device and a minimal required number of satellites. This requirement may,
normally, not be fulfilled at all points of the surface. But by mounting a large number of
satellites the coverage of the object face can be optimized.
It is recommended to mount the satellites already when evaluating the geometry properties of
the object face. By this the recording of the geometry and the paint application can be
performed within the same coordinate system.
It is a common charcteristic of the previously mentioned first measurement systems to utilize
the linear propagation of waves of short wavelength, like light waves, IR-radiation,
microwave radiation or ultrasound, for the position measurement. Positions may be computed
from measured angles or elapsed time by techniques of prior art. Some of the known methods
are called optical tracking in literature. For explanation some possibilities shall be described
Fig. 5 is a sketch of an embodiment of a measurement system containing a number of
satellites at fixed positions. Using PSDs they measure their angular position relative to
sources of modulated light located on the paint application device. The data is transmitted to a
microprocessor, which calculates position information.
Fig. 6 depicts an embodiment of a photometric measurement system with one or more
cameras and/or IR-cameras. The position of the paint application device is determined by
numerical feature extraction and localistion techniques to known visual characteristics of the
paint application device. This procedure can be much simplyfied, if the object face and/or the
paint application device contain light-emitting, reflecting or absorbing (for example colored)
landmarks. Fig. 7 illustrates an embodiment of a landmark. A photometric system is
furthermore well-suited to record color properties of the object face, which can be utilized for
color adjustment for example.
In Fig. 8 a first measurement system is depicted comprizing a scanning laser system. It
contains a laser source 32, a beam deflection unit 33 and an integrated photoelectric
transducer 34. The beam is scanned according to a prescribed temporal course over the object
face 12 and the application device 1. The backscattered light 31 is recorded by the
photoelectric transducer 34 and an image is reconstructed containing the object face and the
paint application device. Also the aforementioned high-contrast landmarks may be involved
In a variant of the system as depicted in Fig. 8 additional light sensors are comprized within
the paint application device, see Fig. 9. In the embodiment two rows of photoelectric
transducers 35 detect the exact time of the laser beam when crossing the transducers thus
allow to determine the position of the paint application device with respect to the known
temporal course of the laser beam.
While above mentioned examples are well known as Outside-In Measurement Methods to
experts, it may further be mentioned, that the first measurement system may also function
according the known Inside-Out Measurement Methods by inverting the functional direction.
Furthermore the position measurent methods based on propagation delay, on the doppler
effect and on interference measurements shall not be excluded from being well-suited for use
in the first position measurement system.
The second measurement system is used for the transition navigation in cases, when the first
measurement system either is unable to supply position data in sufficient rate due to a
measurement frequency, which is low by principle, or due to an interrupted intervisibility
between the paint application device and a critical number of satellites. Sensors out of the
prior art may be employed to measure one or more linear and/or rotational velocities and/or
one or more linear and/or rotational accelerations.
Normally these systems can not carry out an absolute position sensing.
Supplementary information for the calculation of a position can be gained with the aid of
inclinometers and/or magnetometers.
A further possibility to provide position information is to record the object face by a
photoelectric transducer, like a scanner or camera, followed by processing a feature
extraction. Appropriate features may be the already recorded part of the image, if it is rich in
contrast, a reference pattern or constructive features, for example edges. A quality
improvement can be achieved by determining the color value of the surface before and after
paint application, and based on that information calculate the color amount continously by a
Fig. 11 and Fig. 12 show a first embodiment of a paint application device from different
views. An inertial measurement system 6 and velocity sensors 7 provide motion information
in addition to the first measurement system, as represented by a landmark 5. The inertial
system comprizes for example an angular rate sensor to measure the rotational velocity of the
paint application device around an axis perpendicular to the object face and an linear
acceleration sensor measuring the acceleration in motion direction. A pressure sensor 53
allows to control the paint supply pressure. The array of paint application elements is
designed to laterally protrude the rollers 3 laterally by a defined length, the overlap 51, see
Fig. 11. The overlap is beneficial, when using slowly drying paint, because it allows painting
without getting the wheels 3 into contact with previously applied, wet paint.
Fig. 13 shows a second embodiment of a paint application device 1 according to the method
of the invention, which is especially suited to perform reparations or to add finishing touches.
The device comprizes sliding elements 3 to move it over the object face and a paint
application head 24, comprizing special paint nozzles 37, which are chamfered at the lateral
edges. By this paint can also be applied in very concave edges and corners. An image
scanning device 38 directed towards the object face enables to capture a partial image and
thus to identify the own position with respect to the image. Different display and user
interface elements allow to control the device.
When moving the paint application device over the object face beeing in contact with the
same it has to be secured, that the distance and the angle between the paint application nozzles
and the object face are well defined. This can, for example, be achieved by the use of wheels,
rollers, also paint rollers or sliding elements.
Fig. 14 shows a third embodiment of a paint application device 1 comprizing an automatic
control of the distance between the paint application elements and the object face, and
comprizing a possibility to additionally apply a wet priming coat by an integrated paint roller
40. The device allows to perform paint application in a similar way of operation as using a
paint roller. Coaxially within the hub of the roll there is a servo motor 41 for actuating the
portion of the paint application device 1, which contains the paint nozzles 2, relative to the
handhold with the integrated fluid supply 43. In the position 42 only a priming coat is
applied, for example an emulsion paint, in the common way. After the application of the
priming coat at a certain point of the object face, that part of the paint application device,
which includes the paint nozzles 2, is rotated towards the object face by the servo motor, and
a constant distance between the paint nozzles and the object face is maintained by using
distance sensors 39, see the control diagram in Fig. 15. In the depicted emodiment the lateral
dimensions of the paint application head exceed the roller 40 lateraly.
Fig. 16 illustrates the procedure of color application using the device as depicted in Fig. 14.
Priming coat and decorative layer may be applied subsequently or at the same time. To
prevent smearing, the overlap 51 has to be permanently maintained.
Fig. 17 shows an embodiment of an autarc paint application device for facades. The paint
applicaton device is suspended at a cable, which is fed over a pulley, thus allowing vertical
motions. Horizonatal motions are applied be moving the pulley on a horizontal rail.
Fig. 18 shows as an embodiment an autarc, robotic paint application device with a low
pressure suction mechanism 50. The mechanism, an autarc drive and steerability allow
for a free motion also on vertical surfaces. The route of the device is roughly
predetermined by the built-in controller 4. Based on the position measurement and the
knowledge of the past route the paint application device calculates the future route
automatically. Preferably three wheels 3, which are optionally steerable, are used to
move the device on the surface.
Fig.3 sketches a paint application head 24 of the paint application device, comprising
three rows of paint spraying nozzles 20, 21, 22 for different primitive colours. Each paint
is supplied through an inlet pipe from local or peripheral tanks. Fig. 4 shows a paint
application head 24 comprising additional paint application elements 23 for applying a
priming coat or conversion coating.
There are numerous technical possibilities to realise paint application arrays. Thereby
the individual paint nozzles work as claimed in the different techniques known from the
prior art. As appropriate techniques for example the compressed air spraying, the low
pressure spraying, the airless spraying, airmix spraying, supercritical spraying and hot
spraying may be mentioned.
Just as well drop-on demand methods, which produce single droplets and catapult them
onto the working surface, may be employed within a paint application device.
Fast drying paints or hot-melt paints are preferably used for paint application. If not
applicable, paints are to be preferred, which cure fast when exposed to heat, to UV-
radiation or to an air stream. In those cases the paint application device comprises
means for paint curing, setting or fixing at its bottom side, for example a UV-lamp, an air
fan or thermal radiator.
In a variant further layers are applied in parallel to the colour layer within the same
working operation, for example a ground coat or a conversion coating or a coating, that
fixes the colour layer chemically. Paint application elements of the paint application array
may be utilised for this purpose or there may be additional paint application elements in
front of or behind the paint nozzles, which respect to the moving direction. These may be
designed identical or different as the paint application elements.
The ground coat may also be an emulsion paint, into which the color particles are embedded,
either within the wet state of the emulsion paint or as a result of a solubility during color
List of Symbols:
1 Paint application device; 2 Array of color applying elements; 3 Roller/sliding devices; 4
Microcomputer; 5 Light source, heat source; 6 Inertial measurement system as part of the
second measurement system; 7 Optical velocity sensor as part of the second measurement
system; 8 Paint reservoir; 9 Battery; 10 Handhold; 11 Fluidsupply; 12 Surfaceof the object; 13
Satellite of the first measurement system; 14 Position sensing device (PSD) or camera; 15
Optical lens; 16 Obstacle, disturbance; 17 Beam of modulated light 1; 18 Beam of modulated
light 2; 19 Fixation; 20 Paint nozzle for a first basic color; 21 Paint nozzle for a second basic
color; 22 Paint nozzle for a third basic color; 23 Paint application elements for applying a
ground layer or finishing layer; 24 Paint application head; 25 UV-light source for layer
curing; 26 Landmark; 27 Camera chip, projected image; 28 Substrate, transparent; 29
Reference distance; 30 Emitted laser beam; 31 Scattered beam; 32 Laser source; 33 Beam
deflection unit; 34 photoelectric transducer; 35 Retroreflecting Landmark or photoelectric
transducer array; 36 Display, user interface; 37 Paint application head, tilted; 38 Image
scanner; 39 Distance sensor; 40 Paint roll; 41 Coaxial servo motor; 42 Position for applying
base coat; 43 Handle including media supply; 44 Fresh base coat; 45 Original surface; 46
Base coat; 47 Decorative paint coat; 48 Horizontal rail; 49 Vehicle comprizing a pulley, an
integrated drive, and a system control; 50 Low pressure suction mechanism; 51 Overlap; 52
Valve block; 53 Pressure sensor
1. A method for applying paints or varnishes with the aid of an application device in order to
apply a colour design on surfaces of buildings or public or civil engineering works as claimed
in a previously executed implementation of a digital image model into a digital object, which
represents the surface of the object, comprising the steps of
bringing the application device into contact with the surface and moving it arbitrarily on
continuously measuring the position of the application device by use of a non-contact
positioning system or additional motion sensors,
applying paint in accordance with said implementation depending on the position
stopping the application of paint automatically, if paint has already been fully applied at
the positions of the paint applying elements.
2. Method as claimed in claim 1, wherein the application of paint is stopped automatically, if
the position cannot be determined sufficiently accurate with respect to a predetermined
position error acceptance threshold.
3. Method as claimed in claim 1, wherein the application device is maintained in
contact with the surface by manually pressing it onto the surface or by applying a
vacuum between the application device and the surface.
4. . Method as claimed in claim 1, wherein the positioning system is based on position
measurement methods, which utilise fix entities in relation to the surface, to measure
position information relative to, in particular by applying the methods of distance
measurement, angular measurement, telemetry, photometries or imaging measurement
5. Method as claimed in claim 1, wherein a positioning method is used, which utilizes
optoelectronic means to identify position relevant characteristics of the surface in the
near range of the application device.
6. Method as claimed in claim 1, wherein motions of the application device are
measured to derive position information thereof from, in particular velocity and/or
rotational velocity and/or acceleration and/or rotational acceleration.
7. Method as claimed in claim 1, wherein additionally the tilt of the application device
within the earth gravity field and/or the orientation of the application device in
relation to the earths magnetic field is measured and utilised for the position
8. Method as claimed in claim 1, wherein the surface object is recorded by at least one
method as described in one of the claims 3 to 6.
9. Method as claimed in claim 1, wherein the distance between the paint applying
elements and the surface of the object is adjustable.
10. Method as claimed in claim 1, wherein the application device is moved manually.
11. Method as claimed in claim 1, wherein the application device is moved semi-
12. Method as claimed in claim 1, wherein the application device is moved automatically.
13. Method as claimed in claim 1, wherein the application device comprizes at least one
nozzle element, in particular a spraying element.
14. Method as claimed in claim 1, wherein the application device comprizes a row or an
array of spraying elements.
15. A device for carrying out the method as claimed in one of the preceding claims,
a movable application device for applying paints and varnishes,
a position measurement means with respect to the device,
a movement measurement means with respect to the device,
means to adjust the distance between the paint applying device and the surface of the
object when brought into contact.
The invention relates to a method for applying paints or varnishes with the aid of an
application device in order to apply a color design on surfaces of buildings or public or civil
engineering works in accordance with a previously executed implementation of a digital
image model in a previously recorded digital surface object that represents the surface of the
object. According to the invention, the application device moves on the surface of the object
while contacting the surface thereof, the position of the application device is continuously
measured or calculated using motion sensors and paint is applied in accordance with said
implementation depending on the position thus determined. Application of paint by the
application device is automatically stopped if the position of the application device with
respect to a predefined position error acceptance threshhold cannot be determined in a
sufficiently accurate manner or if the corresponding paint or varnish has been fully applied in
the position of the paint applying elements.
|Indian Patent Application Number||1127/KOLNP/2004|
|PG Journal Number||41/2010|
|Date of Filing||09-Aug-2004|
|Name of Patentee||BUSTGENS, BURKHARD|
|Applicant Address||BURKHARD BUSTGENS, HIEBERAINLE 3, 79108 FREIBURG|
|PCT International Classification Number||B05D 1/40|
|PCT International Application Number||PCT/DE2003/00162|
|PCT International Filing date||2003-01-22|