| Dokumentenidentifikation |
EP1227914 15.07.2004 |
| EP-Veröffentlichungsnummer |
0001227914 |
| Titel |
VORRICHTUNG UND VERFAHREN ZUR BESTIMMUNG VON KOORDINATEN UND ORIENTIERUNG |
| Anmelder |
ABB A/S, Billingstad, NO |
| Erfinder |
ANFINDSEN, Arnt, Ole, N-4300 Sandnes, NO |
| Vertreter |
derzeit kein Vertreter bestellt |
| DE-Aktenzeichen |
60011458 |
| Vertragsstaaten |
AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LI, LU, MC, NL, PT, SE |
| Sprache des Dokument |
EN |
| EP-Anmeldetag |
24.10.2000 |
| EP-Aktenzeichen |
009731209 |
| WO-Anmeldetag |
24.10.2000 |
| PCT-Aktenzeichen |
PCT/IB00/01529 |
| WO-Veröffentlichungsnummer |
0001030545 |
| WO-Veröffentlichungsdatum |
03.05.2001 |
| EP-Offenlegungsdatum |
07.08.2002 |
| EP date of grant |
09.06.2004 |
| Veröffentlichungstag im Patentblatt |
15.07.2004 |
| IPC-Hauptklasse |
B25J 1/00
|
| Beschreibung[en] |
|
FIELD OF THE INVENTION AND PRIOR ART
The present invention relates to a device for determining coordinates
of a point of an object in a reference system of coordinates and the orientation
of the object in the space in a measuring position assumed by the object, and a
method according to the preambles of the appended independent claims.
The invention relates in particular, but not exclusively, to such
devices used for programming of robots, such as welding robots or robots for spray
application of paint, which for example "work" with vehicle bodies. This particular
field of use of such a device will hereinafter be described for illuminating the
problem upon which the present invention is based.
The object of the device is usually constituted by a hand tool being
moved by hand by a person between different positions along a work piece, such as
a vehicle body, for storing the coordinates and the direction of a tool of the robot
in these positions. The control unit for the robot interpolates successively the
different positions stored for obtaining a movement of path of the tool of the robot.
Said known coordinates in one position, such as a start position,
are usually obtained by the fact that one or more cameras are watching different
optical points of the object placed in this position, and the real coordinates and
orientation of the object in said start position are determined through the information
so obtained from the camera or the cameras. However, it is sometimes necessary to
move the object to parts along the path of movement of the tool of the robot, which
are hidden by for example the object with which the robot shall "work", such as
a vehicle body. This if for example the case with different positions being located
inside or in any corner of the vehicle body. The object is in such cases moved as
mentioned from the start position to the measuring position hidden at the same time
as parameters associated with the movement are detected and said calculation of
coordinates and orientation of the object in the measuring position may then be
carried out from information from the detecting means about these parameters and
about the start position.
Until now this has been made by using the robot itself for storing
such positions and by measuring the rotation of the different robot arms about their
axes. However, this is a very cumbersome and cost demanding way for calculating
coordinates and orientation in said measuring position.
It is already known through for example DE 19626459-A1 and BE-1010211-A6
how an object may be moved in the way mentioned above for storing the movement of
path of a robot between different positions.
A device and a method according to the introduction are known through
DE-A1-2731041.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a device and a method
of the type defined in the introduction; which enables an increase of the accuracy
when determining the coordinates and the orientation of the object in the measuring
position.
This object is according. to the invention obtained by the fact that
in such a device the object is intended to be moved from said measuring position
to a third position having known coordinates and orientation of the object, the
accelerometers are adapted to detect accelerations and retardations during this
movement, the calculating member is adapted to calculate the coordinates and the
orientation of the object in said third position from information from the accelerometers,
a member is adapted to compare the values of the coordinates and orientation so
calculated with the real ones, and the calculating member is adapted to calculate
new coordinates and orientation for the object in said measuring position from the
acceleration and retardation data detected during the first movement possibly corrected
in accordance with deviations of coordinates and orientation established at said
comparison. It is through this comparison possible to increase the accuracy further
when determining the coordinates and the orientation of the object in said measuring
position, thanks to the compensating for possible errors in the measuring of the
accelerometers made possible here.
According to a preferred embodiment of the invention said means comprise
six accelerometers, three adapted to detect acceleration and retardation for rotation
in three planes being orthogonal with respect to each other and three adapted for
detection of acceleration and retardation of the object in the direction of the
perpendicular to one of said planes each. By arranging six such accelerometers all
the components of the movement of the object at the movement between the start position
and the measuring position may be reliably detected.
According to another preferred embodiment of the invention the device
comprises a member adapted to measure the time needed for the movement of the object
between the start position and the measuring position and between the measuring
position and the third position and the calculating member is adapted to carry out
an application of a weight factor on the correction as a consequence of said deviations
depending upon the relations between the times needed for the two movements. The
compensation may in this way get even better and the reliability of the values calculated
for the coordinates and the orientation in the measuring position may be increased
further.
According to another preferred embodiment of the invention the object
is adapted to be moved between different positions along a path of movement desired
for a part of a robot for storing coordinates and orientation of said part of the
robot in these positions. A movement of path for a robot may by this be stored in
a rapid and efficient way and with a high accuracy also for positions not allowing
optical registration of the position of such an object. It is then advantageous
that the calculating member is adapted to calculate coordinates for a centre point
of a tool of a robot in said measuring position, in which this centre point for
example in the case of a robot for spray application of paint corresponds to the
desired centre hit point for the paint beam of the nozzle. In the case of a robot
for spot welding the measuring position corresponds to the desired position for
the tip of the welding electrode of the robot.
Another preferred embodiment of the invention is exactly related to
that said object is adapted to be moved to bear against an object, which a robot
is intended to treat while assuming said measuring position, which makes it easy
to rapidly and with accuracy obtain exactly the measuring position asked for.
According to another preferred embodiment of the invention one or
more cameras are arranged to watch the object and members are arranged to calculate
said known coordinates and orientation on the basis of information from the camera
or the cameras, and said measuring position is located outside the field of view
for said camera or cameras. The device according to the invention is in exactly
such a case of particular use, i.e. when an optical determination of different positions
of the object is to be carried out and some of these positions are hidden and by
that do not allow any optical determination.
The invention also relates to methods for determining coordinates
of the point of an object in a reference system of coordinates and the orientation
of the object in the space in a measuring position assumed by the object according
to the appended method claims.
The advantages of these methods appear with no doubt from the discussion
above of the device according to the invention and the preferred embodiments thereof.
Further advantages as well as advantageous features of embodiments
of the invention appear from the following description and the other dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
With respect to the appended drawing, below follows a description
of a preferred embodiment of the invention cited as an example.
In the drawing:
- Fig 1
- is a schematical view illustrating a device of the type to which the invention
belongs in a state of use,
- Fig 2
- is a detailed view of an object being a part of the device according to Fig
1,
- Fig 3
- is a schematical view illustrating how accelerometers are arranged and designed
to act according to the invention for the object according to Fig 2 in a device
according to a preferred embodiment of the invention, and
- Fig 4
- is a schematical view illustrating consecutive positions of an object according
to the invention and intended to facilitate the explanation of the method according
to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
It is schematically illustrated in Fig 1 what a device according to
the invention for determining coordinates of a point of an object in a reference
system of coordinates and the orientation of the object in the space in a measuring
position assumed by the object may look like. It is here intended to determine so
many positions along a path of movement of a robot 1 that a control system may interpolate
the movement between these positions and by that control the robot along a path
of movement desired. The control program of the robot is in this way obtained rapidly
and with a high accuracy by moving an object 2 by a person to bear against an object
3, here a vehicle body, to be treated by the robot and the coordinates and the orientation
of the object are determined for each such position. This is obtained by directing
two cameras 4, 5, preferably CCD cameras, towards the vehicle body so that they
have the largest possible part thereof within its field of view. The cameras are
preferably arranged at a distance of 90° with respect to each other with respect
to an imagined circle therethrough around the vehicle body.
The cameras are adapted to send information about the picture they
receive to a member 6 in the form of a computer for calculating the coordinates
of a given point of the object in the system of Cartesian coordinates and the orientation
of the object and send this information further to a unit 7 adapted to control the
robot later on on the basis of the position values calculated. It is then possible
to use only one single camera, but it is then more difficult to obtain a reliable
position determination of the object.
It is illustrated in Fig 2 what an object 2 for use in the way described
with reference to Fig 1 may look like. This object has three arms being perpendicular
to each other according to an axis each in a system of Cartesian coordinates. An
optical reference point 11, 12 in the form of a small ball is arranged on the outermost
end of two of the arms 8, 9. Such optical reference points 13, 14 are also arranged
in the origo of the system of coordinates and in a position along the arm 10, respectively.
The optical reference points 11-14 may be active light signs having an illumination
sequence making them easy to identify individually for the control member 6. It
is the position of these four points in the picture information sent out from the
cameras to the calculating member that is utilized by the calculating member for
calculating the coordinates of a point of the object, more exactly the tip 15 of
the longer arm 10.
This tip 15, which corresponds to the tool centre point (TCP = Tool
Centre Point), is when determining the different positions brought to bear against
the object in question, such as a vehicle body 3 according to Fig 1. Two marker
tines 16, 18 protruding from the arm 10 are also utilized, the extremities of which
may be connected by a line running through the tip 15 for setting the correct orientation
of the object with respect to the vehicle body. The marker tines 16, 17 may be turned
stepwise with 90° around the longitudinal axis of the arm 10 by loosening a setting
knob 18 for maintaining a good geometry of the optical reference points with respect
to the cameras 4, 5. The position set is automatically registered in the control
member 6. When the operator has placed the object in the desired position this actuates
a setting member 19, which preferably sends a signal to the calculating member 6
saying that this shall calculate coordinates and orientation of the object in the
instantaneous position thereof, i.e. on the basis of the picture information exactly
when recorded by the cameras.
It is characterizing for the device according to the invention that
the object, such as the one shown in Fig 2, is provided with accelerometers adapted
to detect accelerations and retardations of the object during the movement thereof.
More exactly, six accelerometers are arranged on the arms of the object, three 20-22
for detecting acceleration and retardation for rotation of the object in three planes
being orthogonal to each other and three 23-25 for detecting acceleration and retardation
of the object in the direction of the perpendicular to one said plane each. How
these are arranged to detect accelerations and retardations in this way is schematically
illustrated in Fig 3. This arrangement of the accelerometers makes it possible to
determine coordinates and orientation of the object in the positions which may not
be determined through information from the cameras since the object is hidden in
these positions by the other object or by the operator.
The position determination by means of the accelerometers takes place
in the following way. When the object has the point 15 in a so called start position
26 (see Fig 4), the coordinates of which and the orientation of the object associated
therewith may be regarded as known since they may be calculated on the basis of
information from the cameras, and the object is moved with the tip 15 to a so called
measuring position 27, in which the object is entirely or partially hidden, the
accelerometers detect accelerations and retardations of the object during this movement
and send information thereabout to the calculating member. This sending of this
information may take place once the measuring position 27 has been reached by actuation
of the setting member 19 by the operator. The calculating member may on the basis
of this information and information of coordinates and orientation associated with
the start position and information about the time needed for the movement calculate
the coordinates for the tip 15 in the measuring position 27 and the orientation
of the object when it is held with the tip 15 in this position. It would for sure
be possible to store the values so calculated as data for the hidden measuring position
27, but the invention intends to increase the accuracy when determining these data
by proceeding in the following way: Once the measuring position 27 has been assumed
by the object the object is moved to the next position 28, here called the third,
in which the object may be regarded to have known coordinates and orientation since
the object here is completely visible to the cameras. During the movement from the
measuring position 27 to the third position 28 the acceleration and retardation
of the object are measured through the accelerometers 20-25. Coordinates and orientation
of the object in this third position is then calculated from information from this
measurement. Thus, during this calculation it is considered that the object has
been moved from the calculated measuring position and then to a new position. Thus,
the coordinates and the orientation of the object calculated in the third position
are established through two consecutive calculations. When this has been done the
values for the third position 28 are compared with those possible to be optically
determined with a high accuracy through the cameras. We now assume that the position
calculated differs somewhat both with respect to coordinates and orientation from
the third position 28 such as shown by the ring 29 in Fig 4. A comparison of the
calculated and so called real position parameters is made and a new calculation
of the hidden measuring position is made on the basis of the difference resulting
from this comparison, and the measuring position may now be considered to be erroneously
calculated to be located at the ring 30. A weight factor is applied to this correction
depending upon the relation between the times needed for the movement between the
points 26 and 27 and 27 and 28, so that when for example a time of 0.3 sec is needed
for the first movement and 0.5 sec for the second one 3/8 of the deviation established
in the third position is utilized for correction of the values calculated for the
measuring position 27. It may in this way be compensated for deviations in the acceleration
and retardation parameters of the accelerometers. It is important that the movement
of the object to the hidden position and then out to a visible position is comparatively
fast for obtaining a good measuring result. A background activity continuously treating
data from the accelerometers and comparing them with optically measured positions
may be carried out in the member 6 for further improving the accuracy. By doing
this continuously during the movement of the object between different positions
associated "gain factors" and "offset values" may be determined through a known
control theory at the same time as the influence of the gravitation may be masked
away.
The invention is of course not in any way restricted to the preferred
embodiment described above, but many possibilities to modifications thereof will
be apparent to a person skilled in the art without departing from the scope of the
appended claims.
It is pointed out that the invention is not at all restricted to the
fact that the object is entirely or partially hidden in said measuring position,
but it is also conceivable to use the device for determining coordinates and orientation
of an object in positions in which the object is well visible. This would be conceivable
in situations without any optical detection and when certain positions are determined
in advance and the object is moved between these known positions for defining one
or more positions therebetween.
It is also possible to arrange less optical reference points than
four on the object, but the measuring may then in some positions be more difficult.
|
| Anspruch[de] |
- Verfahren zur Bestimmung von Koordinaten eines Punktes (15) eines Gegenstands
(2) in einem Koordinaten-Referenzsystem und der Orientierung des Gegenstands im
Raum in einer von dem Gegenstand eingenommenen Erfassungsposition (27), wobei der
Gegenstand von einer Startposition (26) mit bekannten Koordinaten und einer bekannten
Orientierung zu der Erfassungsposition bewegt wird, während diese Bewegung ermittelt
wird, wobei die Koordinaten und die Orientierung des Gegenstands in der Erfassungsposition
aus Information über diese Ermittlung und über die Startposition berechnet werden,
wobei die Beschleunigung und Verzögerung des Gegenstands während der Bewegung erfasst
werden, und die Koordinaten und Orientierung des Gegenstands in der Erfassungsposition
aus Information über diese Erfassung berechnet werden, dadurch gekennzeichnet,
dass der Gegenstand aus der Erfassungsposition (27) in eine dritte Position
(28) mit bekannten Koordinaten und Orientierung des Gegenstands bewegt wird, während
die Beschleunigung und Verzögerung des Gegenstands während dieser Bewegung erfasst
werden, dass Koordinaten und Orientierung des Gegenstands in dieser dritten Position
aus Information von den zwei Erfassungen berechnet werden, dass die Koordinaten
und die für die dritte Position berechnete Orientierung mit den Wirklichen verglichen
werden, und dass Koordinaten und Orientierung des Gegenstands in der Erfassungsposition
dann aus der Erfassung der Beschleunigung und Verzögerung bei der Bewegung von der
Startposition zu der Erfassungsposition berechnet werden, während eine Korrektur
gemäß möglicher, in dem Vergleich erstellter Abweichungen der Koordinaten
und Orientierung erfolgt.
- Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Beschleunigung
und Verzögerung des Gegenstands bei dem Erfassen hinsichtlich einer Drehung in drei,
zueinander orthogonalen Referenzebenen ermittelt werden, und hinsichtlich einer
Translation in der Richtung der Senkrechten zu der jeweiligen Referenzebene in einem
Kartesischen Koordinatensystem, das von diesen Senkrechten gebildet wird.
- Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Zeit,
die für die Bewegung des Gegenstands zwischen der Startposition (26) und der Erfassungsposition
(27) und zwischen der Erfassungsposition und der dritten Position (28) benötigt
wird, erfasst wird, und dass die Korrektur mit einem Gewichtungsfaktor erfolgt,
der auf die Abweichungen in Abhängigkeit von der Relation zwischen den für die zwei
Bewegungen benötigten Zeiten angewendet wird.
- Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet,
dass es sich um einen Gegenstand (2) handelt, der zwischen den Positionen bewegt
wird, um Koordinaten und Orientierung in diesen Positionen als Positionen für einen
Teil eines Roboters auf einer Bewegungsbahn hierfür zu speichern.
- Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet,
dass die bekannten Koordinaten und Orientierung des Gegenstands durch die Tatsache
erhalten werden, dass eine oder mehrere Kameras (4, 5) den Gegenstand in ihrem Gesichtsfeld
in der fraglichen Position (26, 28) haben, derart dass diese Koordinaten und Orientierung
aus Information von der Kamera oder den Kameras berechnet werden können, und dass
der Gegenstand aus dem Gesichtsfeld der Kamera oder der Kameras bei einem Bewegen
von der Startposition (26) zu der Erfassungsposition (27) verschwindet.
- Vorrichtung zur Bestimmung von Koordinaten eines Punktes (15) eines Gegenstands
(2) in einem Koordinaten-Referenzsystem und der Orientierung des Gegenstands in
dem Raum in einer von dem Gegenstand eingenommenen Erfassungsposition (27), wobei
der Gegenstand dafür ausgelegt ist, von einer Startposition (26) mit bekannten Koordinaten
und Orientierung zu der Erfassungsposition bewegt zu werden, wobei die Vorrichtung
umfasst, Mittel (20-25), die dafür ausgelegt sind, mit der Bewegung assoziierte
Parameter zu ermitteln, und Elemente (6), die dafür ausgelegt sind, die Koordinaten
und Orientierung des Gegenstands in der Erfassungsposition aus Information von den
Ermittlungsmitteln über die Parameter und über die Startposition zu berechnen, wobei
die Ermittlungsmittel umfassen, Beschleunigungserfassungsvorrichtungen (20-25),
welche auf dem Gegenstand anzuordnen sind und dafür ausgelegt sind, Beschleunigungen
und Verzögerungen des Gegenstands während der Bewegung zu ermitteln, und wobei das
Berechnungselement (6) dafür ausgelegt ist, die Koordinaten und Orientierung des
Gegenstands in der Erfassungsposition auf Basis von Information von den Beschleunigungserfassungsvorrichtungen
zu berechnen, dadurch gekennzeichnet, dass der Gegenstand dazu vorgesehen
ist, aus der Erfassungsposition (27) in eine dritte Position (28) mit bekannten
Koordinaten und Orientierung des Gegenstands (2) bewegt zu werden, dass die Beschleunigungserfassungsvorrichtungen
(20-25), dafür ausgelegt sind, Beschleunigungen und Verzögerungen während dieser
Bewegung zu ermitteln, dass das Berechnungselement (6) dafür ausgelegt ist, die
Koordinaten und die Orientierung des Gegenstands in der dritten Position aus Information
von den Beschleunigungserfassungsvorrichtungen zu berechnen, dass ein Element dafür
ausgelegt ist, die derart berechneten Werte der Koordinaten und Orientierung mit
den Wirklichen zu vergleichen, und dass das Berechnungselement dafür ausgelegt ist,
die neuen Koordinaten und Orientierung für den Gegenstand in der Erfassungsposition
aus den Beschleunigungs- und Verzögerungsdaten zu berechen, die während der ersten
Bewegung ermittelt wurden, die möglicherweise gemäß in dem Vergleich erstellter
Abweichungen von Koordinaten und Orientierung korrigiert sind.
- Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die Mittel
umfassen, sechs Beschleunigungserfassungsvorrichtungen (20-25), wobei drei (20-22)
ausgelegt sind, eine Beschleunigung und Verzögerung für eine Drehung in drei (23-25),
zueinander orthogonalen Ebenen zu ermitteln, und drei für eine Ermittlung von Beschleunigung
und Verzögerung des Gegenstands in der Richtung der Senkrechten zu jeweils einer
der Ebenen ausgelegt sind.
- Vorrichtung nach Anspruch 6 oder 7, dadurch gekennzeichnet, dass diese
umfasst, ein Element, das dafür ausgelegt ist, die Zeit zu erfassen, die für die
Bewegung des Gegenstands zwischen der Startposition (26) und der Erfassungsposition
(27) und zwischen der Erfassungsposition und der dritten Position (28) benötigt
wird, und dass das Berechnungselement dafür ausgelegt ist, eine Anwendung eines
Gewichtungsfaktors auf die Korrektur als eine Folge der Abweichungen in Abhängigkeit
von den Relationen zwischen den für die zwei Bewegungen benötigten Zeiten durchzuführen.
- Vorrichtung nach einem der Ansprüche 6 bis 8, dadurch gekennzeichnet, dass
der Gegenstand (2) dafür ausgelegt ist, zwischen verschiedenen Positionen (26-28)
entlang einer erwünschten Bewegungsbahn für einen Teil eines Roboters zum Speichern
von Koordinaten und Orientierung des Teils des Roboters in diesen Positionen bewegt
zu werden.
- Vorrichtung nach Anspruch 9, dadurch gekennzeichnet, dass das Berechnungselement
(6) dafür ausgelegt ist, Koordinaten für einen Zentralpunkt eines Werkzeugs eines
Roboters in der Erfassungsposition zu berechnen.
- Vorrichtung nach Anspruch 9 oder 10, dadurch gekennzeichnet, dass das
Berechnungselement (6) dafür ausgelegt ist, die Koordinaten und die Orientierung
eines Punkts zu berechnen, der mit einer Sprühdüse eines Roboters für eine Sprühaufbringung
eines Anstrichmittels assoziiert ist.
- Vorrichtung nach einem der Ansprüche 9 bis 11, dadurch gekennzeichnet, dass
der Gegenstand (2) dafür ausgelegt ist, bewegt zu werden, um gegen einen Gegenstand
(3) zu lagern, der ein Roboter ist, der dafür vorgesehen ist, während eines Einnehmens
der Erfassungsposition eine Behandlung durchzuführen.
- Vorrichtung nach einem der Ansprüche 6 bis 12, dadurch gekennzeichnet, dass
eine oder mehrere Kameras (4, 5) angeordnet sind, um den Gegenstand (2) zu beobachten,
und Elemente (6) angeordnet sind, um die bekannten Koordinaten und Orientierung
auf der Basis von Information von der Kamera oder den Kameras zu berechnen, und
dass die Erfassungsposition (27) außerhalb des Gesichtsfelds für die Kamera
oder die Kameras angeordnet ist.
|
| Anspruch[en] |
- A method for determining coordinates of a point (15) of an object (2) in a reference
system of coordinates and the orientation of the object in space in a measuring
position (27) assumed by the object, said object being moved from a start position
(26) having known coordinates and a known orientation to the measuring position
while detecting this movement, said coordinates and the orientation of the object
in the measuring position being calculated from information about this detection
and about the. start position, said acceleration and retardation of the object being
measured during the movement, and said coordinates and orientation of the object
in said measuring position being calculated from information about this measuring,
characterized in that the object is moved from the measuring position
(27) to a third position (28) having known coordinates and orientation of the object
while measuring the acceleration and retardation of the object during this movement,
that coordinates and orientation of the object in this third position is calculated
from information from said two measurements, that the coordinates and the orientation
calculated for the third position are compared with the real ones, and that coordinates
and orientation of the object in said measuring position is then calculated from
said measurement of the acceleration and retardation at the movement from the start
position to the measuring position while making a correction in accordance with
possible deviations of the coordinates and orientation established in said comparison.
- A method according to claim 1, characterized in that the acceleration
and retardation of the object at said measuring is detected with respect to rotation
in three reference planes being orthogonal to each other and with respect to translation
in the direction of the perpendicular to the respective reference plane in a system
of Cartesian coordinates formed by these perpendiculars.
- A method according to claim 1 or 2, characterized in that the
time needed for the movement of the object between the start position (26) and the
measuring position (27) and between the measuring position and the third position
(28) is measured, and that said correction is made with a weight factor applied
on said deviations depending upon the relation between the times needed for the
two movements.
- A method according to any of the preceding claims, characterized in
that it is an object (2) that is moved between said positions for storing coordinates
and orientation in these positions as positions for a part of a robot in a movement
path for this.
- A method according to any of the preceding claims, characterized in
that said known coordinates and orientation of the object is obtained by the
fact that one or more cameras (4, 5) have the object within their field of view
in the position (26, 28) in question, so that these coordinates and orientation
may be calculated from information from the camera or the cameras, and that the
object disappears from said field of view of said camera or cameras when moving
from the start position (26) to the measuring position (27).
- A device for determining coordinates of a point (15) of an object (2) in a reference
system of coordinates and the orientation of the object in the space in a measuring
position (27) assumed by the object, said object being adapted to be moved from
a start position (26) having known coordinates and orientation to said measuring
position, the device comprising means (20-25) adapted to detect parameters associated
with said movement and members (6) adapted to calculate said coordinates and orientation
of the object in the measuring position from information from the detecting means
about said parameters and about the start position, said detecting means comprising
accelerometers (20-25) to be arranged on the object and adapted to detect accelerations
and retardations of the object during said movement, and said calculating member
(6) being adapted to calculate said coordinates and orientation of the object in
the measuring position on the basis of information from the accelerometers,characterized
in that the object is intended to be moved from said measuring position (27)
to a third position (28) having known coordinates and orientation of the object
(2), that the accelerometers (20-25) are adapted to detect accelerations and retardations
during this movement, that the calculating member (6) is adapted to calculate the
coordinates and the orientation of the object in said third position from information
from the accelerometers, that a member is adapted to compare the values of the coordinates
and orientation so calculated with the real ones, and that the calculating member
is adapted to calculate new coordinates and orientation for the object in said measuring
position from the acceleration and retardation data detected during the first movement
possibly corrected in accordance with deviations of coordinates and orientation
established at said comparison.
- A device according to claim 6, characterized in that said means
comprise six accelerometers (20-25), three (20-22) adapted to detect acceleration
and retardation for rotation in three (23-25) planes being orthogonal with respect
to each other and three adapted for detection of acceleration and retardation of
the object in the direction of the perpendicular to one of said planes each.
- A device according to claim 6 or 7, characterized in that it comprises
a member adapted to measure the time needed for the movement of the object between
the start position (26) and the measuring position (27) and between the measuring
position and the third position (28) and that the calculating member is adapted
to carry out an application of a weight factor on the correction as a consequence
of said deviations depending upon the relations between the times needed for the
two movements.
- A device according to any of claims 6-8, characterized in that
the object (2) is adapted to be moved between different positions (26-28) along
a path of movement desired for a part of a robot for storing coordinates and orientation
of said part of the robot in these positions.
- A device according to claim 9, characterized in that the calculating
member (6) is adapted to calculate coordinates for a centre point of a tool of a
robot in said measuring position.
- A device according to claim 9 or 12, characterized in that the
calculating member (6) is adapted to calculate the coordinates and the orientation
of a point associated with a spray nozzle of a robot for spray application of paint.
- A device according to any of claims 9-11, characterized in that
said object (2) is adapted to be moved to bear against an object (3), which a robot
is intended to treat while assuming said measuring position.
- A device according to any of claims 6-12, characterized in that
one or more cameras (4, 5) are arranged to watch the object (2) and members (6)
are arranged to calculate said known coordinates and orientation on the basis of
information from the camera or the cameras, and that said measuring position (27)
is located outside the field of view for said camera or cameras.
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- Procédé pour déterminer les coordonnées d'un point (15) d'un objet (2) dans
un système de coordonnées de référence et l'orientation de l'objet dans l'espace
dans une position de mesure (27) prise par l'objet, ledit objet étant déplacé d'une
position de départ (26) ayant des coordonnées connues et une orientation connue
à la position de mesure tout en détectant ce déplacement, lesdites coordonnées et
l'orientation de l'objet dans la position de mesure étant calculées à partir d'informations
sur cette détection et sur la position de départ, ladite accélération et le ralentissement
de l'objet étant mesurés pendant le déplacement, et lesdites coordonnées et orientation
de l'objet dans ladite position de mesure étant calculées à partir d'informations
sur cette mesure, caractérisé en ce que l'objet est déplacé de la position
de mesure (27) à une troisième position (28) ayant des coordonnées connues et l'orientation
de l'objet tout en mesurant l'accélération et le ralentissement de l'objet pendant
ce déplacement, en ce que les coordonnées et l'orientation calculées pour
la troisième position sont comparées avec les coordonnées et l'orientation réelles,
et en ce que les coordonnées et l'orientation de l'objet dans ladite position
de mesure sont ensuite calculées à partir de ladite mesure de l'accélération et
du ralentissement lors du déplacement de la position de départ à la position de
mesure tout en effectuant une correction selon les écarts possibles des coordonnées
et de l'orientation établis dans ladite comparaison.
- Procédé selon la revendication 1, caractérisé en ce que l'accélération
et le ralentissement de l'objet au moment de ladite mesure sont détectées par rapport
à la rotation dans trois plans de référence orthogonaux entre eux et par rapport
à la translation dans la direction de la normale au plan de référence respectif
dans un système de coordonnées cartésiennes formé par ces normales.
- Procédé selon la revendication 1 ou 2, caractérisé en ce que le temps
nécessaire au déplacement de l'objet entre la position de départ (26) et la position
de mesure (27) et entre la position de mesure et la troisième position (28) est
mesuré, et en ce que ladite correction est faite avec un facteur de pondération
appliqué sur lesdits écarts en fonction de la relation entre les temps nécessaires
pour les deux déplacements.
- Procédé selon l'une quelconque des revendications précédentes, caractérisé
en ce que c'est un objet (2) qui est déplacé entre lesdites positions pour mémoriser
les coordonnées et l'orientation dans ces positions en tant que positions pour une
partie d'un robot dans un chemin de déplacement pour celui-ci.
- Procédé selon l'une quelconque des revendications précédentes, caractérisé
en ce que lesdites coordonnées et orientation connues de l'objet sont obtenues
du fait qu'une ou plusieurs caméras (4, 5) ont l'objet dans leur champ de vision
dans la position (26, 28) en question, de sorte que ces coordonnées et orientation
peuvent être calculées à partir d'informations provenant de la ou des caméra(s),
eten ce que l'objet disparaît dudit champ de vision de la ou desdites caméra(s)
lorsqu'il se déplace de la position de départ (26) à la position de mesure (27).
- Dispositif pour déterminer les coordonnées d'un point (15) d'un objet (2) dans
un système de coordonnées de référence et l'orientation de l'objet dans l'espace
dans une position de mesure (27) prise par l'objet, ledit objet étant adapté pour
être déplacé d'une position de départ (26) ayant des coordonnées connues et une
orientation connue à ladite position de mesure, le dispositif comprenant des moyens
(20 à 25) adaptés pour détecter des paramètres associés audit déplacement et des
éléments (6) adaptés pour calculer lesdites coordonnées et l'orientation de l'objet
dans la position de mesure à partir d'informations provenant des moyens de mesure
sur lesdits paramètres et sur la position de départ, lesdits moyens de détection
comprenant des accéléromètres (20 à 25) à placer sur l'objet et adaptés pour détecter
les accélérations et les ralentissements de l'objet pendant ledit déplacement, et
ledit élément de calcul (6) étant adapté pour calculer lesdites coordonnées et l'orientation
de l'objet dans la position de mesure en fonction des informations provenant des
accéléromètres, caractérisé en ce que l'objet est destiné à être déplacé
de ladite position de mesure (27) à une troisième position (28) ayant des coordonnées
connues et l'orientation de l'objet (2), en ce que les accéléromètres (20
à 25) sont adaptés pour détecter les accélérations et les ralentissements au cours
de ce déplacement, en ce que l'élément de calcul (6) est adapté pour calculer
les coordonnées et l'orientation de l'objet dans ladite troisième position à partir
des informations provenant des accéléromètres, en ce qu'un élément est adapté
pour comparer les valeurs des coordonnées et de l'orientation ainsi calculées avec
les coordonnées et l'orientation réelles, et en ce que l'élément de calcul
est adapté pour calculer de nouvelles coordonnées et une nouvelle orientation pour
l'objet dans ladite position de mesure à partir des données d'accélération et de
ralentissement détectées pendant le premier déplacement, éventuellement corrigées
d'après des écarts de coordonnées et d'orientation établis lors de ladite comparaison.
- Dispositif selon la revendication 6, caractérisé en ce que lesdits moyens
comprennent six accéléromètres (20 à 25), dont trois (20 à 22) sont adaptés pour
détecter l'accélération et le ralentissement pour la rotation dans trois (23 à 25)
plans orthogonaux entre eux, et trois sont adaptés pour la détection de l'accélération
et du ralentissement de l'objet dans la direction de la normale à l'un desdits plans
chacun.
- Dispositif selon la revendication 6 ou 7, caractérisé en ce qu'il comprend
un élément adapté pour mesurer le temps nécessaire au déplacement de l'objet entre
la position de départ (26) et la position de mesure (27) et entre la position de
mesure et la troisième position (28) et en ce que l'élément de calcul est
adapté pour effectuer une application d'un facteur de pondération sur la correction
en conséquence desdits écarts en fonction des relations entre les temps nécessaires
pour les deux déplacements.
- Dispositif selon l'une quelconque des revendications 6 à 8,caractérisé en
ce que l'objet (2) est adapté pour être déplacé entre différentes positions
(26 à 28) sur un chemin de déplacement souhaité pour une partie d'un robot pour
mémoriser les coordonnées et l'orientation de ladite partie du robot dans ces positions.
- Dispositif selon la revendication 9, caractérisé en ce que l'élément
de calcul (6) est adapté pour calculer des coordonnées pour un point central d'un
outil d'un robot dans ladite position de mesure.
- Dispositif selon la revendication 9 ou 10, caractérisé en ce que l'élément
de calcul (6) est adapté pour calculer les coordonnées et l'orientation d'un point
associé à une buse de pulvérisation d'un robot pour une application de peinture
au pistolet.
- Dispositif selon l'une quelconque des revendications 9 à 11,caractérisé en
ce que ledit objet (2) est adapté pour être déplacé pour porter contre un objet
(3), qu'un robot est destiné à traiter tout en prenant ladite position de mesure.
- Dispositif selon l'une quelconque des revendications 6 à 12,caractérisé en
ce qu'une ou plusieurs caméra(s) (4, 5) sont disposées pour observer l'objet
(2) et des éléments (6) sont disposés pour calculer lesdites coordonnées et orientation
connues en fonction des informations provenant de la ou les caméra(s), et
en ce que ladite position de mesure (27) se situe à l'extérieur du champ
de vision de ladite ou lesdites caméra(s).
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