Method and arrangement of introducing boreholes into a surface of a workpiece mounted in a stationary manner using a boring tool attached to an articulated-arm robot

Patent metadata

Field	Value
Publication number	US-10589394-B2
Application number	US-201615579560-A
Country	US
Kind code	B2
Filing date	May 25, 2016
Priority date	Jun 3, 2015
Publication date	Mar 17, 2020
Grant date	Mar 17, 2020

Abstract

The invention relates to a method and an arrangement for introducing boreholes into a surface of a workpiece (W) mounted in a stationary manner using a boring tool which is attached to the end face of an articulated-arm robot (KR) and which can be spatially positioned by said robot. The method has the following method steps: —positioning the articulated-arm robot-guided boring tool at a spatial position which lies opposite a specified machining location on the workpiece surface at a specified distance therefrom, —producing a rigid mechanical connection which supports the end face of the articulated-arm robot (KR) on the workpiece and which can be released from the workpiece surface, and —machining the surface by moving the boring tool towards the machining location and subsequently engaging the boring tool with the workpiece (W) at the machining location on the workpiece surface while the end face of the articulated-arm robot (KR) is connected to the workpiece. The invention is characterized by the combination of the following method steps: the boring tool is moved towards the workpiece (W) by means of an NC advancing unit attached to the end face of the articulated-arm robot (KR), the boring process is monitored on the basis of information obtained using a sensor system which detects the position of the boring tool relative to the workpiece surface and which is attached to the end face of the articulated-arm robot (KR), and the boring process is terminated upon reaching a specified boring depth.

First claim

The invention claimed is:

1. A method of boring holes into a workpiece while mounted in a stationary position by a boring tool attached to an end face of an articulated-arm robot, comprising:
positioning the articulated-arm robot at a position spaced a distance from a machining location on a workpiece surface;
providing a rigid mechanical connection between the articulated-arm robot and the workpiece surface to support the workpiece under load and which can release the workpiece surface from the load by activating at least three actuators attached to the end face of the articulated-arm robot which are separately actuatable in increments to contact the workpiece surface to apply the load or release the workpiece from the load, the articulated-arm robot operating being positioned to apply the load by contact with the workpiece when the boring tool is boring a hole in the workpiece or to release the workpiece from load;
boring the hole in the workpiece surface by moving the boring tool towards the machining location on the workpiece and subsequentially engaging the boring tool with the workpiece surface at the machining location while the actuators of the articulated-arm robot are connected to the workpiece surface to apply the load thereto;
moving the boring tool towards the workpiece surface under control of a numerically controlled advance unit attached to an end of the articulated-arm robot;
monitoring the boring of the hole in the workpiece surface based on information obtained from a sensor system which detects a position of the boring tool during boring of the workpiece surface and which is attached to the end face of the articulated-arm robot;
terminating the boring process upon reaching a specified boring depth;
positioning the boring tool before boring based on binary data which describes a spatial shape of the workpiece to be machined, a predetermined machining location of the workpiece surface, a center point of the tool, and a spatial position of the boring tool; and
generating at least one of a workpiece coordinate system and a robot coordinate system when the load is applied to the workpiece by the actuators before starting of the boring and then at least one of the coordinate systems are used to control the boring by the boring tool while the load is applied by the actuators.

2. The method in accordance with claim 1 comprising positioning the boring tool in a spatial position opposite to and at a predetermined distance from the machining location on the workpiece to cause the boring of the hole in the workpiece.

3. The method in accordance with claim 1 comprising checking for a corrected spatial location at which the boring tool is to be moved to continue of the hole and positioning the boring tool at the corrected spatial location to perform boring of the hole at the corrected spatial location.

4. The method in accordance with claim 2 comprising checking for a corrected spatial location at which the boring tool is to be moved to continue the boring and positioning the boring tool at the corrected spatial location to perform to continue the boring of the hole at the corrected spatial location.

5. The method in accordance with claim 1 comprising absorbing forces and moments along the articulated-arm robot by rigid mechanical connection of the articulated arm to the workpiece surface.

6. The method in accordance with claim 5 wherein the rigid connection is created by at least one of a magnetic, pneumatic or frictional force between the workpiece surface and the articulated-arm robot.

7. The method in accordance with claim 1 wherein at least one linear actuator is attached to the end face of the articulated-arm robot and the at least one linear actuator is activated to produce the rigid mechanical connection between the workpiece surface and the boring tool and the articulated-arm robot causes the boring tool to contact the workpiece surface and bore the hole.

8. The method in accordance with claim 1 at least one of borehole depth and spatial orientation of the boring tool relative to the workpiece surface at the machining location is determined by the sensor system attached to the end face of the robot.

9. The method in accordance with claim 1 wherein the connection of the articulated-arm robot to the workpiece surface supports the end face, the connection is removed and the articulated-arm robot is moved a distance which is split into at least two sections with a first section being closest to the articulated-arm robot and a second distance being closest to the workpiece surface and the boring tool is moved towards the workpiece surface along the first section at a greater advance speed than along the second section under control of a numerically controlled advance unit attached to the end face.

10. The method in accordance with claim 9 wherein the boring tool is moved along the first and second sections by the numerically controlled advance unit with the boring tool travelling at least along the second section while the boring tool is rotated by a spindle drill and electrical power drawn the spindle drill is measured to detect a first contact between the boring tool and the workpiece surface.

11. The method in accordance with claim 10 comprising:
generating a signal with the sensing system when the boring tool first contacts the workpiece which resets a distance that has been traveled;
detecting a depth of the borehole travel in response to the generated signal;
stopping advancing of the boring tool at a set distance before a target borehole depth is reached; and
the set distance of travel corresponds to a distance required for the boring tool to travelling forward upon reaching the set distance from the boring tool to stop rotation to reach the target borehole depth when rotation stops.

12. A system for drilling boreholes into a workpiece surface at a location on a stationary workpiece by a boring tool attached to an end of an articulated-arm robot comprising:
a control system for spatially positioning and orienting the boring tool relative to a boring location on the workpiece surface;
a sensor system attached to the end of the articulated-arm robot which detects a distance between the end of the articulated-arm robot and the boring location on the workpiece surface;
a rigid detachable mechanical connection attached to the end of the robot arm which supports the robot relative to the workpiece surface having at least three linear actuators attached thereto to an end of the robot arm with the actuators being separately moveable in increments and an actuator mechanism which moves the articulated-arm robot under control of a numerically controlled advance unit attached to the end of the robot arm; and wherein
the control system positions the boring tool based on binary data describing a spatial shape of the workpiece to be bored, a predetermined machining location of the workpiece, a center point of the boring tool and a detected relative position of the boring tool, and generates at least one of a robot coordinate system and workpiece coordinate system when the load is applied to the workpiece by the actuators before starting the boring and when the robot is connected with the workpiece during application of the load to the workpiece with the articulated-arm robot during boring of the hole by the boring tool;
the control system monitors the boring of the workpiece based on information obtained by the sensor system which detects a position of the boring tool relative to the workpiece surface and terminates the boring process upon reaching a specified boring depth;
wherein the articulated-arm robot has a horizontal and vertical operating range of a min

Assignees

• Fraunhofer Ges Forschung

Inventors

• Wanner Martin Christoph
• Dryba Steffen
• Gruendler Mirko

Classifications

• B23B39/14

  with special provision to enable the machine or the drilling or boring head to be moved into any desired position, e.g. with respect to immovable work · CPC title

• B25J11/005

  Manipulators for mechanical processing tasks · CPC title

• B23Q1/48

  with sliding pairs and rotating pairs (B23Q1/46 takes precedence) · CPC title

• B25J15/0095

  with an external support, i.e. a support which does not belong to the manipulator or the object to be gripped, e.g. for maintaining the gripping head in an accurate position, guiding it or preventing vibrations · CPC title

• Y10S901/09

  Closed loop, sensor feedback controls arm movement · CPC title