Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/16—Programme controls
  • B25J9/1679—Programme controls characterised by the tasks executed
  • B25J9/1692—Calibration of manipulator
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/39—Robotics, robotics to robotics hand
  • G05B2219/39192—Compensate thermal effects, expansion of links
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/40—Robotics, robotics mapping to robotics vision
  • G05B2219/40527—Modeling, identification of link parameters
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/49—Nc machine tool, till multiple
  • G05B2219/49207—Compensate thermal displacement using measured distance

Definitions

• the present invention relates to a method for controlling a manipulator and a corresponding robot system.
• Robots and in particular industrial robots, are automatically controlled, freely programmable multipurpose manipulators. They are designed for use in industrial environments and can thus be used in different areas of a production plant.
• an industrial robot can be used to measure one or more measuring points of a component in a processing station or surveying station, or to run a specific path program on a workpiece while processing the workpiece or component by means of, for example, a folding tool.
• the industrial robot Before use, the industrial robot usually needs to be calibrated to obtain a complete kinematic model of the robot. For this purpose, different parameters of the robot mechanics must be determined in order to finally obtain a complete robot model. In addition, the robot must be aligned with respect to the component to be measured or machined: In this case, a reference from the coordinate system of the robot to the coordinate system of the
• reference points can be approached, which represent a fixed point in space.
• a reference point may e.g. be read optically, or manually from one
• Robots are approached. Because the position of a reference point in the
• World coordinate system is defined by detecting the reference point, for example, the exact position of an end effector of the robot using
• Waste heat of electrical components changes the temperature of the
• Robot mechanics This can lead to a change in size of the individual elements, as well as a change in the viscosity of liquids and changes in the
• Reference body or reference body, with known or measured positions measurable.
• the present invention is therefore based on the object to provide a method and a robot system, which minimize the disadvantages listed above - at least partially. It is a further object of the present invention to increase the precision of a robot or manipulator.
• the present invention includes a method for controlling a manipulator.
• the manipulator can be differently pronounced and is controlled based on a manipulator or robot parameter set.
• the method according to the invention comprises providing a calibration, which is preferably a temperature-dependent calibration.
• the providing may include creating the calibration.
• the calibration has the following steps: Repeated start of at least one reference point, and in particular two or M reference points, until a temperature criterion of
• Manipulator is satisfied, and determined, after each start, a calibration set comprising at least one comparison reference point residual drift and a manipulator parameter set.
• the approach of a reference point means a detection of the reference point, which can be done, for example, optically or by touch.
• Reference point has a well-known position.
• the reference points are in the vicinity of the measuring points,
• Processing points or component points on the component can also be arranged directly on the component.
• a residual drift with respect to the approached reference point is determined.
• At least two reference points are approached repeatedly, and after each approach of the two reference points, a calibration set is determined which comprises at least one comparison reference point residual drift and a manipulator parameter set.
• one of the reference points is preferably one
• Component point which is to be approached in the operating mode of the manipulator or robot. Further preferably, one of the reference points is not
• the calibration set preferably comprises a comparison reference point residual drift with respect to this
• each calibration set comprises a manipulator parameter set which has been created on the basis of the residual drifts in relation to at least one comparison reference point residual drift at the reference point.
• the temperature criterion is selected such that the starting and determining is repeated until the temperature of the robot is in a stable state and changes only marginally.
• the calibration is preferably performed while the robot is heating.
• the temperature of the robot changes rapidly and reaches a constant value after a certain time. During this time, preferably the calibration or
• the method according to the invention for controlling a manipulator also has a start-up of, in particular exactly one or N, reference points (s). This Start-up is in normal operation of the manipulator, or also
• the method comprises determining a current reference point residual drift. Consequently, in the productive mode, the instantaneous reference point residual drift with respect to the
• the method according to the invention comprises calculating a
• At least the manipulator parameter set from the calibration is used to calculate the correction parameter set. It is the
• Correction parameter set are determined, with a suitable value or
• Manipulator parameter set can be selected from the calibration based on the determined instantaneous reference point residual drift.
• the method according to the invention comprises controlling the manipulator based on the calculated correction parameter set.
• the current robot model can be updated using the correction parameter set, or even be replaced by this.
• control 25 not only the robot model can be optimized, but also track points can be adapted from a path planning.
• control preferably comprises measuring with the aid of the manipulator below
• a distance measurement can be carried out by means of the manipulator, wherein the
• Manipulator preferably its suitable device, such. has a laser.
• control may also include moving the manipulator in consideration of the correction parameter.
• the "reference point” can thus be any point in the environment of the
• Manipulator may for example be a component point, ie a point on a component or workpiece.
• the term “comparison reference point residual drift” may describe a residual drift at a reference point which is determined in the course of the calibration.
• the term “instantaneous reference point residual drift” may describe a residual drift at a reference point, which is determined in the course of the operating mode
• a “calibration set” may be a dataset that includes a plurality of values, such as a comparative reference point residual drift and a manipulator parameter set
• One, several, or all calibration sets determined during calibration may be provided in a controller of the manipulator or separately “Restdrift” itself does not have to be corrected, so it can only be a "drift”.
• providing the calibration includes creating the calibration.
• the calibration is carried out before the production operation of the manipulator, so that the calibration already exists during the working operation or measuring operation of the manipulator.
• the correction parameter sets can be determined directly based on the calibration, so that the manipulator can be controlled precisely based on the correction parameter set.
• the repeated starting comprises a repeated approach of two reference points, wherein preferably one of the reference points is a component point.
• the model parameters or robot parameters can be optimized efficiently with respect to the points approached in the production mode.
• the model parameters or robot parameters can be optimized efficiently with respect to the points approached in the production mode.
• the determined calibration sets comprise two comparison reference point residual drifts and one manipulator parameter set.
• calculating the calibration set comprises the steps of: selecting a calibration set based on the determined instantaneous reference point residual drift such that the comparative reference point residual drift of the selected one Calibration set is closest to the determined instantaneous reference point residual drift, and creating the correction parameter set based on the selected calibration set.
• a best fit calibration set is selected so that the difference between the determined instantaneous reference point residual drift and the comparative reference point residual drift of the selected calibration set is minimal.
• the calibration set may include creating a correction parameter set based on the manipulator parameter set of the selected calibration set.
• a calibration set is selected, wherein the comparison reference point residual drift from the calibration with the instantaneous reference point residual drift from the productive operation is closest, so that in the
• Correction parameter set and consequently for controlling the manipulator, such as the start or measurement of a component point can be used.
• calculating the correction parameter set comprises the steps of: selecting at least two different calibration sets based on the determined instantaneous reference point residual drift so that the comparison reference point residual drifts of the selected calibration sets are closest to the determined instantaneous reference point residual drift and creating of
• the person skilled in the art understands that more than two calibration sets can also be selected based on the instantaneous reference point residual drift determined in the production mode and can be used for the calculation of the correction parameter set. Thus, for example, if three calibration sets have been selected, a correction parameter set can be calculated based on a spline interpolation of the calibration sets or the corresponding manipulator parameter sets.
• the method according to the invention can also be combined with other methods for the compensation of different drifts. In particular, the method according to the invention is suitable for minimizing residual drift or the effect of residual drift.
• a calibration is thus carried out in which a great many (temperature-dependent) states of the robot are detected.
• a suitable manipulator parameter set from the calibration can thus be used for the instantaneous state of the manipulator.
• the present invention allows the
• Positioning accuracy of a robot or manipulator to improve In this case, for example, a high accuracy of better than + 0.15 mm can be achieved.
• the present invention further comprises a robot system having means for carrying out the method according to the invention.
• the means include in particular a robot controller.
• the present invention includes a computer-readable medium containing instructions that, when executed by a processing system, perform steps to control a manipulator according to the inventive method for controlling a manipulator.
• Fig. 1 shows the sequence of the calibration according to the present invention
• Fig. 2 shows an inventive method for controlling a manipulator.
• FIG. 1 schematically shows the sequence or process 10 of a (temperature-dependent) calibration according to the present invention.
• the process 10 begins in step n.
• a reference point is approached by the manipulator. This reference point is preferably not on the component, but is provided independently of the component.
• a comparison reference point residual drift with respect to the approached in step 12 reference point is determined.
• step 14 a component point is approached, i. a point on that too
• a comparison component residual drift is determined, ie the residual drift between the manipulator and the approached component point.
• a correction parameter set is created.
• a manipulator parameter set or model parameter set is determined on the basis of at least the comparison reference point residual drift determined in step 13 and / or the comparison component residual drift determined in step 15.
• this manipulator parameter set is linked to the comparison reference point residual drift determined in step 13. Subsequently, this correction parameter set is stored in a corresponding calibration database.
• step 17 it is checked whether the temperature of the manipulator has exceeded a predefined limit value. Alternatively, in decision 17 it can also be checked whether the temperature of the manipulator has reached a constant value. If the decision 17 is negative, a new calibration set is determined by continuing the process at step 12. If the decision 17 is positive, the calibration ends in step 18.
• each calibration set is determined with the calibration, wherein in each calibration set a comparison reference point residual drift is associated with a manipulator parameter set.
• Each calibration set was thereby at a determined different temperature of the manipulator. Only when the temperature of the manipulator is preferably approximately stable, the calibration is terminated.
• FIG. 2 schematically shows the sequence 20 of a method according to the invention for controlling a manipulator. This method is preferably used in
• step 21 a (temperature dependent) calibration is provided.
• the calibration has been performed according to the process illustrated in FIG. 1 and provides appropriate calibration sets.
• step 23 a reference point is approached by the manipulator. This reference point is identical to the reference point which was approached or measured during the calibration.
• step 24 an instantaneous reference point residual drift is determined, ie the residual drift between the manipulator and the approached reference point.
• step 25 two calibration sets are selected from the calibration.
• Calibration sets are calculated by comparing the determined in step 24 instantaneous reference point residual drift and the comparison reference point residual drift of
• Calibration sets of calibration selected.
• the comparison determines which comparison reference point residual drifts of the calibration sets of calibration are closest to the instantaneous reference point residual drift determined in step 24. Accordingly, then two calibration sets with the nearest
• step 26 the manipulator parameter sets of the selected calibration sets associated with the two comparison reference point residual drifts are interpolated for the calibration, and a correction parameter set is calculated on the basis of the interpolation.
• step 27 the manipulator is based on at least the

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• Engineering & Computer Science (AREA)
• Robotics (AREA)
• Mechanical Engineering (AREA)
• Manipulator (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=56178305

Family Applications (1)

Country Status (4)

Family Cites Families (9)

• 2015
  • 2015-06-22 DE DE102015211405.8A patent/DE102015211405A1/de not_active Withdrawn
• 2016
  • 2016-06-20 EP EP16731036.6A patent/EP3310536A1/de not_active Withdrawn
  • 2016-06-20 CN CN201680036646.2A patent/CN107771118A/zh active Pending
  • 2016-06-20 WO PCT/EP2016/001047 patent/WO2016206797A1/de unknown

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