USRE34597E - Robot-laser system - Google Patents

Abstract

A robot-laser system having a minimum number of mirrors for reflecting a laser beam from a fixed laser beam source to a desired location wherein the mirrors are mounted within the hollow, servo-controlled parts of the robot to move therewith. Only a single mirror is mounted within is associated controlled part to reflect the laser beam as it travels between adjacent controlled parts. The robot has a number of degrees of freedom constituted by two orthogonally related linear movements along intersecting longitudinal axes and two orthogonally related rotary joints having intersecting pivotal axes. Preferably, two of the mirrors are mounted so that the laser beam strikes and is reflected from both points of axes intersection within two of the controlled parts. In one of disclosed embodiments a mirror mounted in the base of the robot reflects the laser beam from the source to the other mirrors.

Description

.Iadd.

This is a continuation of co-pending application Ser. No. 221,515 filed on Jul. 19, 1988 now abandoned which is a Reissue of Ser. No. 06/684,248 now U.S. Pat. No. 4,650,952. .Iaddend.

TECHNICAL FIELD

This invention relates to a robot-laser system and, in particular, to a robot-laser system having mirrors mounted within the moving parts of a robot for automatically controlling the path of the laser beam as the robot moves.

BACKGROUND ART

Robot capabilities range from very simple repetitive point to point motions to extremely versatile movement that can be controlled in sequence by a computer as a part of a complete integrated manufacturing system. Robots have been used in many material processing applications including cutting, trimming and welding.

Laser applications can be divided into several general categories including the measurement of spacial parameters, material heating and/or removal, non-destructive probing of resonant phenomena, communications, optical processing, laser-induced chemical reactions and weapons.

The combination of a laser with a robot allows the laser to operate with a degree of freedom previously unknown. The combination of the two technologies, if successfully performed, is suitable for most laser applications, including material processing applications. The same laser can be used in processing many kinds of materials by controlling the speed and the power of the laser. This laser can cut metal, cut glass, trim plastic or weld aluminum. Because robots are typically controlled by a programmed computer, the same computer can be used to regulate the laser's power. Consequently, in a flexible manufacturing line, parts can be cut or welded one after the other simply by adjusting the pwoer of the laser.

Lasers are currently in operation in both commercial and industrial environments. For example, many parts of an automobile are processed with lasers. Also, a large percentage of vision systems that measure depth are laser-based.

Another industrial use of the laser is laser-assisted machining wherein the laser beam is applied in front of a cutting tool to reduce tool wear and cutting forces. Such an application results in fewer tool changes, decreased total tool wear and tool cost, increased cutting speeds and increased amounts of materials that can be cut.

Two types of lasers are typically used in material processing applications, solid state and carbon dioxide lasers. The carbon dioxide lasers are relatively unlimited in power. The solid state lasers are limited in power and require more elaborate shielding than the carbon dioxide lasers.

Popular uses of metal-working lasers include seam, spot and fusion welding, cutting, drilling, surface hardening, metal marking, scarfing, deburring, trimming and heat treating. The advantages of laser processing are particularly evident in welding. Welding done with lasers often requires no additional work such as grinding. With traditional welding, welds must be reworked a large percentage of the time. Therefore cost savings are an important aspect of laser welding.

Two methods have developed in order to link lasers with robots. One method is to move a part via a robot into the laser beam. The other way is to move the beam via the robot to the part. The latter method is effective if the part is too large to be moved easily or when contouring is necessary.

One relatively new concept of linking robots with lasers is using more than one robot to share a laser beam. Sharing systems are only limited by the cycle times of the various operations being done.

Another concept that is relatively new is mounting the laser on the top of an articulated-arm robot.

Another method of linking the robot with a laser incorporates two mirrors in each joint of a laser arm which is manipulated by the robot. The apparatus comprises a tubular linkage mechanism. The mechanism is then manipulated by the robot to direct the laser beam along the desired path. The mirrors must be held in place very securely and precisely for the beam cannot be misdirected even a fraction of a degree as it proceeds along its path. Vibrations of the robot that could affect the mirror positions must be taken into account in such a design. A focusing lens concentrates the laser energy and directs it to a singular point with a high power density. The robot must be very accurate to direct the beam to a precise area on a workpiece. A longer focal length lens can be used to compensate for robot inaccuracies. However, the resulting beam is focused over a larger area so that both power density and speed are lower.

Despite the above-noted problems in linking the laser with the robot, it is highly desirable to forge this linkage especially because the laser is an ever sharp tool having a non-contact method of operation. The use of the laser also eliminates the need for tactile feedback, adaptive circuitry, sensory perception and tool wear because the laser and the part do not touch each other.

As previously mentioned, in manipulating high power laser beams in welding robots, the beam is usually reflected off several mirrors located at the joints of a tubular linkage mechanism which has several articulations. The mechanism is then maminpuated by the robot to direct the laser focal point along the desired path. Two mirrors are usually required at each joint to direct the beam from one link orientation to another. Since manipulators generally require five to seven articulations to provide the neccessary motion to access the workpiece at a specific orientation the number of mirrors needed to provide the laser beam at the workpiece can be as many as 14. Accuracy of the laser path depends on the accuracy of the robot and laser arm and mirror alignment which are not corrected for by programming. Also, power loss, overheating and cracking, misalignment, higher cost of accuracy and space and weight limitations make this approach impractical for general purpose manipulators. Such an approach is disclosed in the U.S. Pat. No. to Sharon 3,913,582.

United States patents which disclose rotatably adjustable mirrors include the U.S. Pat. Nos. to Ayres 3,528,424, Ditto 4,059,876 and Malyshev et al 4,144,888.

The U.S. Pat. No. to Carstens et al. 4,429,211 discloses a pipe welding system including a seam tracker to keep the focal spot on the seam to compensate for axial and radial variations of the pipe. An active beam alignment system operates in real time to compensate for angular misalignment. Individually controlled mirrors reflect the laser beam in order to weld the pipe.

Other patents of less relevance include the U.S. Pat. Nos. to Mefferd et al 3,736,402, Fletcher et al 3,888,362 and Sakuragi et al 4,443,684.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a robot-laser system which is more accurate, has a lower cost and has greater reliability than prior art robot-laser systems.

Another object of the present invention is to provide an improved robot-laser system which allows light-weight, low power, low cost manipulators to be used for heavy duty applications such as the welding of industrial components and automobile bodies. In such application, the robot will only carry and manipulate at least one lightweight mirror rather than heavy welding equipment or relatively clumsy and heavy laser beam-guiding articulations.

Yet still another object of the present invention is to to provide a robot-laser system which allows the manipulator to be built with simplicity of design, ease of use, high accuracy and low cost due to the relatively light weight of the laser beam manipulating parts of the system.

In carrying out the above objects and other objects of the present invention, a robot-laser system constructed in accordance with the present invention includes a laser beam source, a robot including a plurality of automatically movable parts and at least one mirror for reflecting the laser beam from the source to the desired location wherein the mirror is mounted on a movable part of the robot to move therewith and to reflect the laser beam as the laser beam travels between adjacent movable parts.

As a result, the robot automatically moves the mirror relative to and in synchronization with the movement of other movable parts and any other mirrors.

Further in carrying out the above objects and other objects of the present invention, the robot-laser system preferably includes a like plurality of motors. Each of the motors independently and controllably moves its respective movable part.

Also, preferably, the robot has a number of degrees of freedom constituted by two orthogonally related linear movements along intersecting longitudinal axes and two orthogonally related rotary joints having intersecting pivotal axes.

Preferably, the laser beam source is positioned at a fixed location, but may be mounted on the robot itself.

The advantages of this design are numerous including:

reduction in the required number of mirrors;

less power loss;

full control of laser beam orientation through normal robot programmability;

ease of teaching by the lead-through method; insensitivity to slight mirror misalignment in assembly since all mirrors are under active feedback control through their associated robot part in which they are mounted; and

reduced cost and higher precision obtainable from use of lightweight manipulators.

Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, partially broken away, illustrating a robot-laser system constructed in accordance with a first embodiment of the present invention;

FIG. 2 is an end view, partially broken away, and in cross-section of the system of FIG. 1;

FIG. 3 is an enlarged side elevational view, partially broken away, of a second embodiment of a wrist mechanism of the robot-laser system;

FIG. 4 is an end view, partially broken away, of the wrist mechanism of FIG. 3 rotated 90°;

FIG. 5 is a side elevational view, partially broken away, of a third embodiment of a wrist mechanism of the robot-laser system and

FIG. 6 is a side elevational view, partially broken away, illustrating a second embodiment of a robot-laser system constructed in accordance with the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, there are illustrated in FIG. 1 a first embodiment of a robot-laser system constructed in accordance with the present invention. The embodiment is collectively indicated at 10. Thesystem 10 is useful in directing a laser beam to a desired location which may be occupied by a workpiece.

Briefly, the robot-laser system of FIG. 1 includes a minimum number of mirrors whch are internally mounted within the moving parts of a relatively lightweight, lower power and low cost robot, generally indicated at 14. Therobot 14 comprises a .[.six-axes .Iadd.six-axis manipulator with freedom to rotate aboutaxes 11, 12, and 13 and freedom to move linearly alongaxes 11, 12 and 13. Therobot 14 can be used for such heavy duty applications as welding of industrial components such as automobile bodies. Therobot 14 need only carry and support relatively lightweight mirrors instead of heavy welding equipment or clumsy and heavy laser beam-guiding articulations. This lightweight payload allows therobot 14 to be built with simplicity of design, ease of use, high accuracy and low cost.

Therobot 14 comprises an arm assembly movably mounted on a hollow base, generally indicated at 24. The arm assembly includes an outer arm, generally indicated at 16 and an inner arm, generally indicated at 17. Thearms 16 and 17 are hollow and are fluidly interconnected to allow alaser beam 18 generated by alaser beam source 18a to pass therethough after passing through thebase 24. A .[.first.]. .Iadd.third .Iaddend.mirror 19 is fixedly mounted on a top surface of theinner arm 17 by asupport 20. A .[.second.]. .Iadd.fourth .Iaddend.mirror 22 is fixedly supported on a mountingmember 23 which, in turn, is fixedly mounted to alower base section 25 of thehollow base 24. Thesupport 20 is located within acavity 21 formed in theouter arm 16 so that thelaser beam 18 relfected from the .[.second.]. .Iadd.fourth .Iaddend.mirror 22 .Iadd.at a junction point 47 .Iaddend.is, in turn, reflected at a 90° angle from the .[.first.]. .Iadd.third .Iaddend.mirror 19 .Iadd.at a junction point 41.Iaddend..

Thebase 24 includes anupper base section 26 which rotates about the axis 11 relative to thelower base section 25 upon actuation of aservo motor 27. Theservo motor 27 is mounted on the outer surface of thelower base portion 25.Bearings 30 rotatably support theupper section 26 on thelower section 25. Theservo motor 27 is mechanically coupled to theupper base section 26 by gearing 28 mounted on theoutput shaft 29 of theservo motor 27 to rotate therewith.

Theinner arm 17 and, consequently, the entire arm assembly is mounted on theupper base section 26 to rotate therewith. More particularly, a lower portion of theinner arm 17 is connected to adrive nut 31 which is threadedly engaged on adrive screw 32, one end of which in turn, is rotatably supported at the top of theupper base section 26 bybearings 37. The opposite end of thescrew 32 is coupled to thedrive shaft 33 of aservo motor 34 by acoupling 35. Theservo motor 34, in turn, is fixedly mounted on aU-shaped suport 39 of theupper base section 26. Theinner arm 17 is slidably supported within thesupport 39. Because thedrive screw 32 is fixedly connected to the lower portion of theinner arm 17, rotation of thedrive screw 32 alternately raises or lowers theinner arm 17 along the axis 11 relative to thesupport 39.

Theouter arm 16 moves linearly along theaxis 12 by mens of a rack and pinion gear connection to aservo motor 40 mounted on theinner arm 17. More particularly, apinion gear 36 is mounted on adrive shaft 38 of theservo motor 40 to rotate therewith. A rack 42 is fixedly mounted on theouter arm 16 in driving engagement with thepinion gear 36. A slide portion 44 of the inner arm .[.16.]. .Iadd.17 .Iaddend.is slidably supported within thearm 17 bylinear bearings 46.

Therobot 14 also includes a .[.two-axes.]. .Iadd.two-axis .Iaddend.wrist mechanism, generally indicated at 48, which is supported for rotation about .[.the.]. .Iadd.a first wrist .Iaddend.axis 12 on theouter arm 16 bybearings 49. Thewrist mechanism 48 includes a hollowinner knuckle 50 and a hollowouter knuckle 52 supported on theinner knuckle 90 for rotation about theaxis 13 bybearings 54. .Iadd.Theaxes 12 and 13 intersect at a first junction point 43. .Iaddend.Theinner knuckle 50 is rotatably driven about theaxis 12 by aservo motor 56 which is mounted on the top surface of theouter arm 16. Gearing 58 interconnects theinner knuckle 50 to thedrive shaft 60 of theservo motor 56 to transfer the rotary motion of thedrive shaft 60 to theinner knuckle 90.

In the same fashion, theouter knuckle 52 is rotatably driven about .[.the.]. .Iadd.a second wrist .Iaddend.axis 13 by aservo motor 62 which is mounted on theinner knuckle 50. Gearing 64 interconnects theouter knuckle 52 to the drive shaft .[.66.]. .Iadd.67 .Iaddend.of theservo motor 62 to transfer the rotary motion of the drive shaft .[.66.]. to theouter knuckle 52.

A .[.third.]. .Iadd.first .Iaddend.mirror 66 is fixedly mounted on the inner surface of theinner knuckle 50 to reflect thelaser beam 18 between the .[.second.]. .Iadd.third .Iaddend.mirror 19 and a .[.fourth.]. .Iadd.second .Iaddend.mirror 68 which is fixedly mounted on the inner surface of theouter knuckle 52. A focusinglens 70 is fixedly mounted 46 within theouter knuckle 52 between themirror 68 and the free end of thewrist mechanism 40 to focus thelaser beam 18 .[.on.]. .Iadd.along a third wrist axis 69 and onto .Iaddend.a workpiece for worpiece or material processing. .Iadd.Theaxes 13 and 69 intersect at a second junction point 45. .Iaddend.

Thelower section 25 of thebase 24 is mounted for sliding movement along theaxis 15 on a track, generally indicated at 72. Thetrack 72 includes adrive screw 74 which extends between a pair of spaced apartflange portions 76 of an elongated support, generally indicated at 78. One end of the drive screw is rotatably supported on thesupport 78 bybearings 80. The other end of thedrive screw 74 is in driving engagement with thedrive shaft 82 of aservo motor 84 through a coupling 86. Theservo motor 84 is mounted on thesupport 78.

Thebase 24 of therobot 14 is mounted on aslide member 88 which in turn, is mounted for movement on thedrive screw 74 by adrive nut 90. Extensible light shields or bellows .[.92.]. .Iadd.91 .Iaddend.extend between thelaser source 18a and thelower section 25 of the base 24 to protect the laser beam from the environment during movement of therobot 14 on thetrack 72.

Thelaser beam source 18a is preferably located in a fixed position. However, it is to be understood that alternatively. the laser beam source may be mounted on the wrist, the base or the inner or outer arms of therobot 14 depending on the weight of the laser beam source and the load-carrying capacity of the particular robot part.

Thelaser beam 18 is aimed in a direction parallel to theaxis 15 so that it is reflected by themirror 22 to travel along the axis 11 until it strikes themirror 19. Thelaser beam 18 reflects off themirror 19 and travels along theaxis 12 until it strikes themirror 66. Thelaser beam 18 then reflects off themirror 66 and travels along theaxis 13 until it strikes themirror 68. Thelaser beam 18 reflects off themirror 68 and travels along an axis .Iadd.69 .Iaddend.spaced apart and parallel to theaxis 12. Thelens 70 focuses thelaser beam 18 before thelaser beam 18 exits thewrist mechanism 48. alternately, themirror 68 can be shaped as a focusing mirror to eliminate thelens 70.

While not shown, therobot 14 may include other equipment such as grippers, fixtures or other equipment. Also, the robot-laser system 10 may include additional mirrors in order to help in directing thelaser beam 18 favorably to a workpiece.

Referring now to FIGS. 3 and 4 there is illustrated a second embodiment of a wrist mechanism 48' including servo motors 56' and 62' and mounted at the free end of a modified outer arm 16' for rotation of its inner and outer knuckles 50' and 52', respectively.

The servo motor 56' rotatably drives the inner knuckle 50' through ashaft 92 which is coupled at one end thereof to the rotary drive shaft 60' of the servo motor 56' by acoupling 93. Theshaft 92 extends in a direction parallel to theaxis 12 and is rotatably supported therein by abearing block 94. Gearing 96 couples the inner knuckle 50' to the opposite end of theshaft 92. Bearings 49' rotatably support the inner knuckle 50' on the outer arm 16'.

In a similar fashio, the servo motor 62' rotatably drives the outer knuckle 52' through ashaft 98 which is coupled at one end thereof to the rotary drive shaft .[.66'.]. .Iadd.67' .Iaddend.of the servo motor 62' bycoupling 100. Theshaft 98 extends along a direction parallel to theaxis 12 and is rotatably supported therein by abearing block 102. Gearing, including acentral gear 104 couples the outer knuckle 52' to the opposite end of theshaft 98. Bearings 54' rotatably support the outer knuckle 52' and thecentral gear 104 on the inner knuckle 50'.

Externally mounted mirror assemblies, generally indicated at 106 and 108, are adjustably mounted on the inner and outer knuckles 50' and 52', respectively, to allow adjustment of the position of their corresponding mirrors 66' and 68'.

Referring now to FIG. 5 there is illustrated a third embodiment of a wrist mechanism, generally indicated at 48". Themechanism 48" is substantially the same as thewrist mechanism 48 except that anouter knuckle 52" is directly coupled to the rotary drive .[.axis 66".]. .Iadd.shaft 67".Iaddend. of aservo motor 62" to rotate about theaxis 13. Theservo motor 62" is mounted on aflange member 109 fixedly mounted on theinner knuckle 50".Bearings 54" rotatably support theouter knuckle 52" on theinner knuckle 50".

Referring now to FIG. 6 there is illustrated a second embodiment of a robot-laser system collectively indicated by reference numeral 10'. The system 10' includes a robot, generally indicated at 14', which is mounted on a floor, such as afactory floor 110 which has space there-under for mounting alaser source 18a' therein. For the sake of simplicity, only the bottom portion of the robot 14' is shown since the top portion is substantially identical to that of therobot 14. The robot 14' comprises a five-axes manipulator with freedom to rotate about three axes (only one of which is shown at 11' in FIG. 6) and freedom to move linearly along two axes (only one of which is shown at 11' in FIG. 6). The construction of FIG. 6 allows themirror 22 to be eliminated.

TEACHING THE ROBOT OF THE ROBOT-LASER SYSTEM

In programming or teaching any one of therobots 14 or 14', the positions of the mirrors are ignored since they are fixed relative to the robot part in which they are mounted. Teaching can be done by beaming a low power laser beam or ordinary light via a source (not shown) which is temporarily attached to the robot. Such a light beam will simulate the path of the high power beam under normal operation. After such a source is attached to the robot, the robot can be led through a desired path by any of several commonly utilized methods. One method, such as used with light-weight manipulators, is simply to lead the unpowered manipulator by hand. Another is to command individual axes to move as desired from a push button terminal or by means of a joy stick (neither of which are shown). A third method utilizes a force sensing device (not shown) which is attached to the robot and senses the force applied when the robot is led through its path. The programmable controller is utilized to read the sensor transducer outputs to command the drive circuits of the actuators or servos of the robot and provide the desired motion.

The operator decides on the desired path by aiming the light beam to the desired location on the workpiece At specific points along the desired path, .[.axes.]. .Iadd.axis .Iaddend.positions can be recorded as well as the desired status of the laser beam i.e. whether it is triggered "on" or "off" at what power level when "on". The recording command is usually input by pushing a button that commands the controller to read the output of the several feedback devices. These devices may indicate the position of the robot actuators and/or the status of the support equipment at any recording point.

Once path points are recorded they are usually stored in computer memory or peripheral discs for recall in a playback mode whereby the robot can retrace the path described by the recorded points. In the playback mode the force sensor, if used, can be removed as well as any auxiliary light beam source.

The advantages of the above-described robot-laser systems are numerous. For example, the number of mirrors required to be used in manipulating the laser beam has been greatly reduced from the number required by the prior art. There is less power loss and there is full control of laser beam orientation through robot programmability. Teaching such robot-laser systems through the lead-through method is made relatively easy. Furthermore, slight mirror misalignment in assembly is not fatal since all the mirrors are under active feedback control through their associated robot part in which they are mounted. Finally, the reduced cost and the higher precision attainable by use of light-weight manipulators enhances the commerical prospects of such robot-laser systems.

The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Claims (10)

What is claimed is:

1. A robot-laser system for providing a laser beam at a desired location, the system comprising:

a laser beam source for generating a laser beam;

a robot having at least three degrees of freedom and including a base and a .Iadd.single motorized .Iaddend.robot arm .Iadd.having a motor mounted on said arm .Iaddend.supported on said base, the robot arm having first and second elongated arm parts, the second arm part projecting from the first arm part, the robot arm having a wrist mechanism located at the distal end of the second arm part, said arm parts and said wrist mechanism being hollow and fluidly interconnected to define a laser beam path therewithin extending through said first arm part, along the entire projecting length of said second arm part and through said wrist mechanism, said arm parts and said wrist mechanism being adpated to direct the laser beam therewithin; .[.and.].

at least one mirror for reflecting the laser beam, a single mirror being mounted to and supported by said arm therewithin at a position of fluid interconnection between the arm parts to move therewith and reflect the laser beam wherein a first one of said degrees of freedom comprises a linear movement of said first arm part along an axis coincident with said laser beam path, a second one of said degrees of freedom comprises a linear movement of said second arm part along a second axis coincident with said laser beam path through the second arm part and a third one of said degrees of freedom comprises a rotary movement of one of said arm parts about said laser beam path.Iadd.; and

first and second drive means for linearly driving the first and second arm parts, respectively, and third drive means for rotatably driving the one of said arm parts about said laser beam path. .Iaddend.

2. A robot-laser system for providing a laser beam at a desired location, the system comprising:

a laser beam source for generating a laser beam;

a robot having at least three degrees of freedom and including a hollow base and a .Iadd.single motorized .Iaddend.robot arm .Iadd.having a motor mounted on said arm .Iaddend.supported on said base, the base being fluidly interconnected to said source, the robot arm having a hollow first arm part and an elonaged, hollow second arm part projecting from the first arm part, the robot arm having a hollow wrist mechanism located at a distal end of the second arm part, said wrist mechanism having at least one rotational axis and at least one knuckle rotatably supported on said axis; said first arm part being fluidly interconnected with said base, said first arm part being fluidly interconnected to said second arm part and said second arm part and said wrist mechanism being fluidly interconnected to define a laser beam path therewithn extending through the base, through the first arm part, along the projecting length of said second arm part and through said wrist mechanism; said base, said first and second arm parts and said wrist mechanism being adpated to direct the laser beam therewithin; .[.and.].

at least two mirrors for reflecting the laser beam, a first one of said mirrors being mounted to and supported by said knuckle therewithin to move therewith and reflect the laser beam, and a single mirror being supported by said arm therewithin at a position of fluid interconnection between the arm parts to reflect the laser beam to the first one mirror wherein a first one said degrees of freedom comprises a linear movement of said first arm part along an axis coincident with said laser beam path, a second one of said degrees of freedom comprises a linear movement of said second part along a second axis coincident with said laser beam path through the second arm part and a third one of said degrees of freedom comprises a rotary movement of one of said arm parts about said laser beam path.Iadd.; and

first and second drive emans for linearly driving the first and second arm parts, respectively, and third drive means for rotatably driving said one of said arm parts about said laser beam path. .Iaddend.

3. The invention as claimed in claim 1 or claim 2 wherein said robot has at least five degrees of freedom.

4. The invention as claimed in claim 1 or claim 2 wherein said first and second degrees of freedom are constituted by two orthogonally related linear movements along intersecting longitudinal axes, and wherein the single mirror is mounted so that the laser beam strikes the single mirror at the point of intersection of the longitudinal .[.axis.]. .Iadd.axes. .Iaddend.

5. The invention as claimed in claim 1 or claim 2 wherein the number of mirrors is less than the number of degrees of freedom of the robot.

6. The invention as claimed in claim 1 or claim 2 including focusing means mounted on said robot for focusing the reflected laser beam at the desired location.

7. The invention as claimed in claim 6 wherein said focusing means comprises a focusing lens.

8. The invention as claimed in claim 1 or claim 2 including a track wherein said robot is mounted on said track to move thereon.

9. The system as claimed in claim 1 or claim 2 wherein said base is fluidly interconnected to said source by an aperture extending completely through a wall of said base. .Iadd.

10. The system of claim 1 or claim 2 wherein each of said first, second and third drive means includes a servo motor. .Iaddend.

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