WO2009086495A2

WO2009086495A2 - Robotic arm for accurate positioning in three-dimensional space, measurement of three-dimensional coordinates, and remote tooling operations in three-dimensional space

Info

Publication number: WO2009086495A2
Application number: PCT/US2008/088394
Authority: WO
Inventors: Sam Stathis
Original assignee: Sam Stathis
Priority date: 2007-12-28
Filing date: 2008-12-29
Publication date: 2009-07-09
Also published as: WO2009086495A3

Abstract

CMM (coordinate measurement) functions are incorporated into robotic devices used a construction site system. The construction site system is capable of determining the absolute position of any physical point in three- dimensional space upon which the moving robot is to operate, that position is determined globally relative to monuments with known positions. A CMM determines the position of a point in three-dimensional space locally relative to itself. Combining the CMM functions with the global position determination functions improves the accuracy and precision of point location. The device disclosed in the Present Application comprises a motorized robotic arm having a plurality of moveable joints that give the arm the ability to reach out and touch any point in three-dimensional space within its reach. Attached to the robotic arm is a probe with a stylus having a sensor that will measure the coordinates of the point relative to itself. Coordinate information is then transmitted wirelessly to a control station. The device also transmits its absolute position wirelessly to a control station. Several different devices may be attached to the stylus. Coordinate measurement is only one function that can be performed. One device of significance would be an electronic distance measurement unit. This would enable the robot arm to be used either as a laser pointer and a distance measurement unit or as a total station. The arm can also be detected and seen by other robots and monuments on the site, and these other devices transmit the position of the Present Invention to the control station. The device has a locator device (such as a passive corner cube prism or an active wireless beacon) that can be seen by the other devices at the site.

Description

TITLE OF INVENTION ROBOTIC ARM FOR ACCURATE POSITIONING IN THREE-DIMENSIONAL SPACE, MEASUREMENT OF THREE-DIMENSIONAL COORDINATES, AND REMOTE TOOLING OPERATIONS IN THREE-DIMENSIONAL SPACE CROSS REFERENCE TO RELATED APPLICATIONS This Present Patent Application is the non-provisional counterpart of US Provisional Application Serial No. 61/017,457 filed on December 28, 2007. This Present Application claims the benefit of and priority to said Provisional Application 61/017,457. BACKGROUND OF THE INVENTION Coordinate measurement machines in three-dimensional space for modeling purposes are prior art. The typical coordinate measurement machine (CMM) comprises a moveable probe having a stylus or measuring device at its end. The stylus may be a mechanical, electrical, or optical sensor. The probe advances toward an object to be mapped in three- dimensions. If the stylus has a mechanical or electrical sensor at its end, the stylus will touch a point on the object, and the sensor will transmit coordinate information electronically to an analog to digital converter based on the physical position of the probe. If the stylus has an optical sensor at its end, the probe will emit a light beam (typically a laser), and will measure the amount of time for the optical echo to return to the sensor. When the word "robot" is used, most people imagine an android with a head, torso, arms, and legs moving about performing tasks and sometimes talking. While such robots do exist, the typical robot consists of a movable arm having joints and capable of movement in such a manner as to perform work. In many instances, it would be logical to combine the function of a robot arm with that of a CMM as well as EDM (electronic distance measurement) to perform work and measurement simultaneously. A particularly relevant example of a robotic CMM may be found in the PCT Application Serial No. PCT/EP 2006/007810 by Stephen James Crampton - WIPO Publication No. WO 2007/017235 A2 published on February 15, 2007 (hereinafter Crampton '810). Another example may be found in the PCT Application Serial No. PCT/GB 2004/001827 also by Stephen James Crampton - WIPO Publication No. WO 2004/096502 published on November 1 1 , 2004 (hereinafter Crampton '827). Both applications by Crampton describe robotic CMM's for use on automobile assembly lines. Particular attention should be paid to FIG. 7 of Crampton '810 which illustrates the device. In addition, particular attention should be paid to FIG. 69 of Crampton '827 (described on page 105) showing the robotic CMM mounted on a vehicle used to access difficult to reach areas. The function of a robotic arm in an automobile assembly line is to automate the work of assembling an automobile. Normally, the robotic arms are in a fixed position, and they wait for the partially assembled automobile to come to them for the work to be done. The robotic arms can weld or screw parts together, lift objects and move them into place, and perform other assembly tasks with a reasonable degree of accuracy. The function of a CMM in an automobile assembly line is to measure points on the surface of assembled or partially assembled automobile to determine whether the automobile is being assembled precisely. In his patent applications, Crampton combined the functions of the robotic arm and a CMM. His combination apparatus generally remains in a fixed position at the workstation of the assembly line. However, when work needs to be performed in hard to reach areas, Crampton mounts his combination apparatus on a vehicle that is moved to a desired spot by an operator via a remote control device. When the vehicle arrives at its appointed place, three spikes emerge downward, touch the floor, and lift the vehicle off the floor so that the wheels are suspended in the air. The three spikes form a tripod that provides stability so that the combination apparatus may perform the work. Crampton is silent regarding the size of a vehicle that would not be toppled over in such a situation once the robot/CMM arm is extended. Once Crampton's vehicle arrives at a particular position relative to the automobile assembly, it would most likely remain fixed in that position for a long time. Also, Crampton's apparatus must remain electrically physically connected to the controlling device. The Present Applicant has previously submitted the following US patent applications: Provisional Filed Non-Prov. Filed Title

60/805,983 06/28/2006 11/766,672 06/21/2007 Method for Accurately and Precisely Locating and Marking a Position in Space Using Wireless Communications

60/862,439 10/21/2006 11/875,678 10/19/2007 System for Accurately and Precisely Locating and Marking a Position in Space Using Wireless Communications and Robotics

60/910,791 04/09/2007 - - System and Method

Capable of Navigating and/or Mapping Any Multi-Dimensional Space These above referenced applications have been incorporated by reference herein. In these applications, the Applicant disclosed a system to be used in the construction industry. In the construction industry, creating a site {e.g., a building, a sewage treatment plant, a water park, etc.) requires accurate placement of building materials such as plumbing, electric wiring, ducts, and conduits. In the past, architects created blueprints by hand, surveyors marked off critical points on the site, and workers re-measured everything in an effort to accurately and precisely locate the position of the building materials. In the more recent past, blueprints were replaced with digitally generated CAD drawings. Surveyors replaced traditional transits with laser equipment. However, the process for building a site remains the same despite technological improvements. The inventions disclosed by the above referenced applications is for a system and apparatus comprising a plurality of robotic devices, some fixed and some moveable, working together in a wireless network to navigate within a site which may or may not have an existing structure. The robotic devices can be fixed, portable, transportable, or vehicular mounted. The system employs global positioning system (GPS) technology and continually operating reference (COR) technology combined with CAD to physically map the site to the CAD drawing with very high accuracy. Not only do the robotic devices know where they are in the site relative to one another, but they also know where they are globally. Some of the component devices are fixed in position. They serve as monuments, beacons, and controllers of the other devices. Other devices are mounted on vehicles that move about at the command of the fixed devices. These robotic devices paint lines on floors and walls, carry materials from one location to another, drill holes, measure distances so as to map to the CAD drawings, etc. The use of robotic and CMM devices in the construction site system (disclosed in the above reference patent applications) serves a different purpose than the use of such devices on an automobile assembly line. The primary purpose of an assembly line is to bring a workpiece to a first worker (either human or machine) who then performs a very specific task. Once that task is finished, the workpiece moves on to the next worker who performs a different task. The first worker is then free to perform the same task on the next workpiece as it is delivered to him. In the Applicant's construction site system, a plurality of roving robots move to various positions on the site simultaneously, the positions being determined from the CAD drawings by a computer, and these robots prepare the site and perform preliminary machine operations for the workmen who install plumbing, electrical wiring, structural members, etc. The robots are controlled from a central station in a wireless network where the position and orientation of every robot at any time is known. Regarding the CMM functions, in an automobile assembly line, the CMM measures coordinate points relative to itself. In the Applicant's construction site system, the CMM measures points in an absolute coordinate system. The CMM arm is utilized differently. The real time measurements generated by the CMM are used in conjunction with the previously referenced guidance systems. In an automobile assembly line, CMM is used to accurately measure parts. In the construction site system, CMM is used for determining distances on the site. This new CMM data aids navigation thereby augmenting accuracy. SUMMARY OF THE INVENTION It is necessary to incorporate CMM functions into some of the robotic devices used in the Applicant's construction site system. Even though the present system is capable of determining the absolute position of any physical point in three-dimensional space upon which the moving robot is to operate, that position is determined globally relative to monuments with known positions. A CMM determines the position of a point in three-dimensional space locally relative to itself. Combining the CMM functions with the global position determination functions of the present system is redundant, but such redundancy improves the accuracy and precision of point location. The device disclosed in the Present Application comprises a motorized robotic arm having a plurality of moveable joints that give the arm the ability to reach out and touch any point in three-dimensional space within its reach. Attached to the robotic arm is a probe with a stylus having a sensor that will measure the coordinates of the point relative to itself. Coordinate information is then transmitted wirelessly to a control station. The device is also capable of transmitting its absolute position wirelessly to the control station. Several different devices may be attached to the stylus. Coordinate measurement is only one function that can be performed. The devices could include, inter alia, drill bits, lasers, markers, cutters, etc. One device of significance would be an electronic distance measurement unit. This would enable the arm to be used either as a laser pointer and a distance measurement unit or as a total station. The arm can also be detected and seen by other robots and monuments on the site, and these other devices transmit the position of the Present Invention to the control station. Therefore, the device of the Present Invention must have a locator device (such as a passive corner cube prism or an active wireless beacon) that can be seen by the other devices at the site. It must also be self-leveling. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the navigation, measurement, and workstation system in an enclosure capable of reading fixed reference stations. FIG. 2 illustrates the various functions of a robot arm in the system. FIG. 2A shows a robot arm with a cutting tool. FIG. 2B shows a robot arm with a printing or plotting tool. FIG. 2C shows a robot arm with a plumb visible laser pointer FIG. 2D shows a robot arm with a CMM, laser scanner, or manual point-reading tool. FIG. 2E shows a robot arm with a drilling, engraving, or burning tool. FIG. 3 illustrates typical types of vehicular robots. FIG. 3A shows a wheeled robot vehicle. FIG. 3B shows a tracked robot vehicle. FIG. 3C shows a spider movement robot vehicle. FIG. 3D shows an air cushioned robot vehicle. FIG. 4 illustrates a robotic arm transportable station. FIG. 5 illustrates a corner cubed prism. FIG. 6 illustrates a vehicle mounted master station, having a tool arm, horizontally and vertically scanned visible lasers, and electronic distance measurement devices. FIG. 7 illustrates a robotic master station comprising a robotic arm and a tool. FIG. 8 illustrates a robotic slave station comprising a robotic arm and a tool. FIG. 9 illustrates various Master and Slave Stations interconnected using a computer network. FIG. 10 illustrates an isometric view of a robotic CMM arm having multiple degrees of freedom of movement. FIG. 11 is a side elevational view of the robotic CMM arm of FIG. 10. FIG. 12 shows the robotic CMM arm of FIG. 10 fully extended with motorized joint control. FIG. 13 shows an isometric view of the self-leveling base of the robotic CMM arm. FIG. 14 shows an isometric view of a prosthetic device positioned around a commercial CMM arm that would convert it into a robotic/CMM arm. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates the navigation, measurement, and workstation system described in the Applicant's prior patent applications referenced above. The system is shown in an enclosed construction site with fixed reference stations 1. The drawing also shows a monument 2, a master station 3, a transportable station 4, a robotic arm transportable station 5, and a robotic vehicular station having a robotic arm 6. The devices shown communicate with each other, each performing its own work simultaneously with the other devices. Corner cube prisms (describe later) permit position measurement by laser for each of the devices. Therefore, the fixed reference stations 1 will each consist of a corner cube prism. Any of the devices will seek out the fixed reference stations 1 and will be able to determine its own position relative to these stations. Fixed position monuments 2 serve the same purpose. The master station 3, comprising a Theodolite with a spinning laser, is placed in position on a tripod. A Theodolite device has some robotic functions that allow movement of the head. The spinning laser seeks out the fixed reference stations 1 , and once having found them, triangulates its position relative to absolute coordinates and a CAD drawing of the site. The master station is then able to keep track of the slave stations and the robotic stations. A slave station also has a Theodolite that interacts with the master station. The robotic stations have corner cube prisms mounted thereon, and are therefore trackable by either the master or the slave stations by line of sight. By positioning master and slave stations in appropriate positions, there are no blind spots on the site. FIG. 2 illustrates the various functions of a robot arm in the system. FIG. 2A shows a robot arm with a cutting tool 9. FIG. 2B shows a robot arm with a printing or plotting tool 10. FIG. 2C shows a robot arm with a plumb visible laser pointer 1 1 . FIG. 2D shows a robot arm with a CMM, laser scanner, or manual point-reading tool 12. FIG. 2E shows a robot arm with a drilling, engraving, or burning tool 13. FIG. 3 illustrates the types of robotic vehicle that can be employed in the system. FIG. 3A shows a wheeled robot vehicle 14. FIG. 3B shows a tracked robot vehicle 15. FIG. 3C shows a spider movement robot vehicle 16. This vehicle is capable of walking. FIG. 3D shows an air cushioned robot vehicle. This vehicle operates very much like a hydrofoil 17. Note, each of these vehicles 14 through 17 supports a corner cube prism assembly 18 which is shown in FIG. 5, and will be described later. Laser light impinging upon corner cube prism assembly 18 will be refracted to return along the same line to its source. In this way, the system can determine the precise location of the prism, and consequently the device supporting the prism. FIG. 4 illustrates a robotic arm transportable station. This tripod- mounted station 23 emits a visible laser beam 22, and the distance from the floor can be measured. The station has vertical and horizontal spinning lasers 20 that enable it to find its position relative to the master station, other slave stations, and fixed reference stations. Both the station and the robot arm have prisms 18 so that they may be located by the other stations. The station shown here uses visible laser pointer and electronic distance measurement reading and writing devices 19, 20 to map the local coordinates where the work is to be done. FIG. 5 illustrates a corner cube prism 18. Typically, a corner cube is used to reflect light back along the same incident path. Corner cubes are used to measure distance to a target. A laser beam is sent to the corner cube, and is reflected back to a photoelectric sensor at its source. Based upon the time taken by the light traveling to the corner cube and back, the distance from the laser source to the corner cube target can be measured. This technology was used very effectively during the first Apollo Moon Mission. An array of corner cubes was deposited on the surface of the Moon. A laser beam from Earth was sent to find the corner cube array. Once found, the distance from the Earth to the Moon was measured with very high accuracy. Normally a corner cube reflects back in only one direction. However, the corner cube prism of the Present Invention places four corner cubes orthogonal to each other. Therefore, the corner cube prism may be found by a laser beam from any direction. FIG. 6 illustrates a vehicle mounted master station, having a robotic tool arm, horizontally and vertically scanned visible lasers, and electronic distance measurement devices. Here, instead of mounting a Theodolite master station on a tripod, the Theodolite 25 is mounted on a robotic vehicle 28. A robot arm capable of performing any of the functions 9-13 shown in FIG. 2 is mounted on the vehicle. The head of the robot arm is interchangeable. Shown in the drawing is a visible laser pointer 21. Of course, any of the other tools shown in FIG. 2 may be used. There is an automatic toolbox 29 mounted on vehicle 28, said toolbox containing the tools which the robot arm can fetch and fasten on itself. Mounted on Theodolite 25 are a vertical spinning laser 26 and a horizontal spinning laser 27. These spinning lasers are used to precisely locate any other component of the system. In the drawing, visible laser pointer 19 is mounted atop Theodolite 25. Finally, both the Theodolite and the robot arm have corner cube prisms 18 mounted thereon so that their positions may be precisely known to the system. FIG. 7 illustrates a robotic master station 30 comprising a robotic arm 31 and a tool. As in the previous drawing, Theodolite 25 is mounted atop wheeled or tracked robotic vehicle 28. Automatic toolbox 29 contains the various tools to be place on robotic arm 31. Note the corner cube prisms 18 mounted on vehicle 28 and robot arm 31. FIG. 8 illustrates a robotic slave station 32 comprising a robotic arm 31 and a tool. Note that the slave station does not have a Theodolite mounted on the vehicle. The robotic arm 31 is mounted on wheeled or tracked vehicle 28. Automatic toolbox 29 contains the interchangeable tools. Corner cube prisms 18 are mounted on the vehicle and robot arm so that the slave station may be precisely known to the system. FIG. 9 illustrates various Master and Slave Stations interconnected using a computer network. The use of the robotic stations to perform CMM functions as well as work functions was disclosed originally in the Applicant's above referenced prior patent applications. For example, FIG. 2D was taken directly from U.S. Provisional Application Serial No. 60/862,439 filed by the Applicant on October 21 , 2006. The necessity for CMM functions were described in that application. The problem with the robotic arms shown in FIG. 2 (and other figures) is that their movement is confined to a single plane. Figures 10-12 show a robotic arm that has multiple degrees of freedom of movement. This arm can point to and reach around 360° to any point within its reach. Its only limitation is created by its fully extended length (shown in FIG 12). The robotic/CMM arm shown in the figures have three joints. It is controlled by robotic control motors 33. At its base 35, the arm is capable of yaw movement. Each of the three joints 34 is capable of roll and pitch movement. In this way, the arm may be directed to any point in space within its reach. The base is motorized so that the entire arm may be rotated through 360°. A stylus 36 is positioned at the end of the robot arm to precisely move to a desired point in space. Stepping motors are positioned at each of the joints to permit rotational movement. Motorized movement is controlled wirelessly from the master station and the slave stations. Note the prism located on the robot arm. FIG. 13 shows an isometric view of the self-leveling base of the robotic CMM arm. Three stepping motors 37 rotate geared nuts 39 that control bolts 38 that individually raise or lower vertically to accomplish leveling. Leveling is automatic, and it is controlled by a drop of mercury residing in a hemispherical receptacle. When the drop of mercury positions itself at the center of the hemisphere, the device is leveled. Leveling is necessary so that the device can properly orient itself in the absolute coordinate space. This robotic/CMM arm is both capable of performing work and of measuring the coordinates of any point in the three-dimensional space. As mentioned before, the redundancy of measurement is necessary for the work to be positioned precisely. FIG. 14 illustrates a prosthetic device that can retrofit a commercially available CMM arm that only performs coordinate measurement to act as a robot arm. FIG. 14A shows prosthetic devices positioned at the joints of the arm. FIG. 14D shows an isolated prosthetic device as in FIG. 14A. The device comprises an attachment bracket, a gear box and a motor module. FIG. 14B shows a typical CMM stylus with a prism. FIG. 14C shows an EDM module and a corner cube prism.

Claims

CLAIMSI claim:

1. A method for determining a location of a point in three-dimensional space relative to a system comprising fixed reference points by determining the location of that point relative to a mobile robotic device the location of which relative to the fixed reference points is known, wherein said mobile robotic device comprises a robotically controlled arm, said method comprising: a) mounting a sensor on the robotically controlled arm; b) electronically moving the robotically controlled arm to a position where the sensor electronically detects position coordinates of the point in three-dimensional space relative to the mobile robotic device; c) transmitting a signal from the mobile robotic device to a receiver in a computer, wherein said signal represents the position coordinates of the point in three-dimensional space detected by the sensor; and d) computing the position of the point in three-dimensional space relative to the fixed reference points.

2. The method of claim 1 performing work at the location of the point in three-dimensional space, wherein the robotically controlled arm additionally comprises a tool to perform said work.

3. The method of claim 2 wherein the work to be performed is cutting, printing, plotting, marking, drilling, engraving, carving, or burning.

4. The method of claim 1 further comprising using a laser beam to light up the location of the point in three-dimensional space.

5. The method of claim 1 wherein the position of the mobile robotic device is itself robotically controlled.

6. The method of claim 5 wherein the mobile robotic device further comprises wheels, tank-like tracks, legs that move the device, or air- cushioned propulsion.

7. The method of claim 1 wherein the mobile robotic device further comprises at least one corner cube prism.

8. The method of claim 7 wherein the robot arm further comprises at least one corner cube prism.

9. The method of claim 1 wherein a Theodolite device is mounted on the mobile robotic device.

10. The method of claim 9 wherein the Theodolite device comprises at least one spinning laser.

11. A mobile robotic device at a known position to a system comprising fixed reference points, wherein said mobile robotic device measures a location of a point in three-dimensional space relative to itself and transmits the location of that point to a computer in the system comprising fixed reference points, and wherein said mobile robotic device comprises: a) a device that enables the computer to compute the location of the mobile robotic device relative to the fixed reference points; b) a robotically controlled arm; c) a sensor mounted on the robotically controlled arm that detects the position of the point in three-dimensional space relative to the mobile robotic device; d) a device that transmits the position of the point in three- dimensional space to the computer.

12. The mobile robotic device of claim 11 wherein the robotically controlled arm further comprises a tool that performs work at the point in three- dimensional space.

13. The mobile robotic device of claim 12 wherein the tool is interchangeable with other tools.

14. The mobile robotic device of claim 12 wherein the tool is of a type selected from the group consisting of cutting, printing, plotting, marking, drilling, engraving, carving, and burning.

15. The mobile robotic device of claim 11 further comprising a laser beam to light up the location of the point in three-dimensional space.

16. The mobile robotic device of claim 11 further comprising elements that permit the mobile robotic device to move to another position relative to the fixed reference points by remote control.

17. The mobile robotic device of claim 16 further comprising wheels, tank- like tracks, legs that move the device, or air-cushioned propulsion.

18. The mobile robotic device of claim 11 wherein the device that enables the computer to compute the location of the mobile robotic device relative to the fixed reference points is a corner cube prism.

19. The mobile robotic device of claim 11 further comprising a Theodolite device mounted thereto.

20. The mobile robotic device of claim 29 wherein the Theodolite device comprises at least one spinning laser.

21. The mobile robotic device of claim 11 wherein the robotically controlled arm moves to enable the sensor to detect the position of the point in three-dimensional space without movement of the mobile robotic device itself.

22. The mobile robotic device of claim 21 wherein the robotically controlled arm is capable of roll, pitch, and yaw movement.