WO1996008675A1 - Remotely operated managed maintenance robotic system - Google Patents

Abstract

A remotely operated managed maintenance system adapted for remote operation of health physics and maintenance tasks within a containment of a nuclear facility includes a fixed, elevated track (14), a wheeled trolley (18) capable of movement along the track, a rotatable gantry (20) depending from the trolley, a robotic arm (24) having six motorized joint assemblies depending from an end of the gantry distal the trolley, and a universal coupling arrangement for attaching a selected end effector (26) adapted for performing a specific task. The operation of the entire system is remotely controlled from a location outside the containment by a control circuit assembly that is capable of providing a real-time computer-simulated image of the mechanical components and fixed objects in its vicinity. The control circuit assembly is also capable of planning a path for the trolley, gantry and robotic arm that avoids the fixed objects.

Description

REMOTELY OPERATED MANAGED MAINTENANCE ROBOTIC SYSTEM

CROSS REFERENCE TO RELATED APPLICATION This application is related to Serial No. 07/607,705, to Hecht, et al., for IMPROVED ROBOTIC SYSTEM FOR SERVICING THE HEAT EXCHANGER TUBES OF A NUCLEAR STEAM GENERATOR, filed November 11, 1990, and which relates to a robotic arm and control system.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The invention relates to robotic systems, and, in particular, to remotely operated and programmable robotic systems for performing health physics and maintenance functions in the platform area of a nuclear steam generator.

2. Description of the Prior Art; Operation of nuclear powered steam generators engenders high health physics costs. Primary steam generator work can average approximately 25% of general outage exposure. This maintenance activity is the largest percentage of exposure for any single activity. Because of this, primary steam generator work presents a good opportunity for use of significant radiation exposure reduction techniques. About 75* of steam generator exposure is typically obtained from platform work, wherein health physics function are normally performed by radiation protection technicians. These functions include beta and gamma surveys, air sampling, decontamination, and job observation. Maintenance technicians also perfo platform functions such as bolt hole cleaning. The tre in the nuclear industry is that these types of exposur will increase as reactors and the steam generators th power age.

Robotic systems exist for servicing heat exchang tubes of nuclear powered steam generators. One su system the ROSA I robotic system, by Westinghouse Electr Corporation of Pittsburgh, Pennsylvania, that includes six degree of freedom robotic arm capable of manipulati an end effector, or tool, in combination with a contr circuit assembly that simultaneously controls both t movement of the arm and the operation of an attached e effector. The system is adapted for use in servicing a repairing heat exchanger tubes mounted in the tube she of the channel head of a nuclear steam generator. T robotic arm is mounted in a fixed position at one en while the other end, carrying the end effector, is free move. This system is useful for servicing a limited are such as a tube sheet, but, because of its limited range motions, is not readily adaptable to reaching all are that must be serviced on the platform surrounding a ste generator. Merely lengthening one or more segments of t robotic arm would make the robotic arm too large a unwieldy to use. Further, nuclear power plants typicall include a pair of steam generators that, although locat near each other, are too far apart to be serviced by single robotic arm fixed to one location.

Other robotic systems, such as, for example th disclosed in U.S. Patent No. 5,049,028, to Assano, et al . include a segmented robotic arm capable of movement alo a linear rail. However, such systems are not easil adaptable to service a plurality of steam generator wherein it may be necessary to move the robotic arm arou corners. Other robotic systems, for example, the syst disclosed in U.S. Patent No. 5,109,718, to Gugel , et al . include a telescoping arm having one end carried by carriage running on a curved rail and a free end capable of carrying a test unit. U.S. Patent No. 5,178,820, to Glass, III, et al . , discloses a tool positioning assembly for use inside a steam generator. A robotic arm capable of manipulating a tool at a free end is supported by a base moveable on a track supporting the arm space. The track consists of two straight sections joined by an arcuate section permitting movement of the base in a vertical plane. While useful within the limited confines of the interior of a steam generator, this is not a practical configuration for accessing the platform areas of a plurality of adjacently located steam generators, which are spaced apart horizontally rather than vertically. In addition, the system requires that a human operator service the robotic arm by installing and removing any tool carried by the free end of the robotic arm, thereby exposing the human operator to considerable radiation. This is impractical from a health physics standpoint wherein it would be desirable to be able to change end effectors on the robotic arm by remote operation.

None of the prior art systems has the range of motion, lifting capacity, or flexibility necessary to service the platform area of a nuclear powered steam generator. Therefore, there is a need for a system capable of movement to different areas of a nuclear reactor system containment for performing health physics and maintenance functions in the platform areas of steam generators associated with the nuclear reactor. It is also desirable to be able to change end effectors attachable to a free end of a robotic arm and capable of different functions, by automated or remote means.

SUMMARY OF THE INVENTION These and other needs are satisfied with the present invention for a remotely operated managed maintenance robotics system (ROMMRS) , or platform server, for performing maintenance health physics, and other function in potentially hazardous areas, such as, for example within a containment of a nuclear power plant, an particularly in the platform area near one or more stea generators. Use of the platform server for performing variety of routine and emergency maintenance and healt physics functions can significantly reduce costs o operating a nuclear facility.

The platform server includes a mechanical arrangemen that includes a robotic arm having a plurality o

■articulated joint assemblies, a trolley movable in horizontal plane along a fixed-rail track which can hav straight and arcuate sections, and a horizontal gantr coupled at a proximate end to the trolley by a firs coupling arrangement for rotating the gantry about a firs vertical axis and coupled at a distal end to a proximat end of the robotic arm by a second coupling arrangement An end effector coupling arrangement, including a firs end effector coupler on a free, distal end of the roboti arm and a mating second end effector coupling on an en effector, provides a capability for automated or remotel controlled coupling of the robotic arm to an end effector A control circuit assembly includes a controller fo controlling movement of each of the joint assemblies o the robotic arm, the trolley, the first coupling, and th end effector. A pa, zoom and tilt video monitorin system, including a video camera having a swivelling an rotating mounting arrangement to the gantry, can be use for remote viewing of the end effector. Operation of th video monitoring system can also be controlled by th control circuit assembly.

According to another aspect of the invention, th mechanical arrangement provides eight degrees of freedo motion for an end effector. The track, trolley and gantr system, including the first coupling arrangement, provide two degrees of freedom of movement of the robotic arm an the end effector in a horizontal plane. The robotic ar system provides six degrees of freedom of movement. A first joint arrangement coupling between the second coupling arrangement and a first arm segment provides rotation of the first arm segment about the second vertical axis. A second joint arrangement coupling between the first arm segment and a second arm segment provides rotation of the second arm segment about a first horizontal axis. A third joint arrangement coupling between the second arm segment and a third arm segment provides rotation of the third arm segment about a second horizontal axis parallel to the first horizontal axis. A fourth joint arrangement coupling between the third arm segment and a fourth arm segment provides rotation of the fourth arm segment about a third horizontal axis parallel to the first and second horizontal axes. The first, second, third and fourth arm segments define a common plane. A fifth joint arrangement coupling between the fourth arm segment and a fifth arm segment provides rotation of the fifth arm segment about a first wrist axis that is in the common plane and transverse to the fourth arm segment. A sixth joint arrangement coupling between the fifth arm segment and the first end effector coupling provides rotation of the first end effector coupling, and an end effector attached thereto, about a second wrist axis collinear with the fifth arm segment.

The end effector can be chosen from one of several types of tools adapted to perform different health physics and maintenance functions in the platform area of one or more nuclear powered steam generators. For example, a grappling end effector can be selected for grasping and manipulating another object, such as a vacuum nozzle coupled to a vacuum device, or a filter cartridge used for obtaining a sample of airborne matter. Another type of end effector is a swipe tool for surveying a contaminated area with a swab capable of gathering particulates or liquids. A third type of end effector is adapted for surveying an area with a radiation detector, such as a monitoring sensor, like a Geiger-Mueller counter fo surveying gamma and alpha radiation. A fourth type of en effector includes a mechanism for reaching areas otherwis blocked by obstructions to movement of the arm, such as for example, a telescoping arm, which can include a surve radiation detector, such as, for example, an integrate dosage sensor or a monitoring sensor. A fifth type of en effector is an adhesive roller tool for cleaning up o sampling particulates on a surface in the platform area According to another feature of the invention, th coupling mechanism for the end effector is remotel operable. This enables end effectors to be change without requiring a human operator to be on the platform To this purpose, the end effectors are each stored in a end effector rack in the platform area where they can b reached by the robotic arm. The universal end effecto coupling arrangement provides electric power and electri signal lines and pneumatic air lines from the robotic ar to the end effector. According to another aspect of the invention, a winc may be mounted to the distal end of the gantry for liftin objects too heavy for the robotic arm to move. The winc can also be controlled by the control circuit assembly.

An important feature of the invention is the contro system which preferably includes a single CPU operate controller which is capable of simultaneously controllin the trolley, the gantry, the robotic arm, and an computer-controlled mechanism present in the end effecto being delivered by the arm or coupled to the trolley gantry-arm system. Movement of the various components ca be controlled by real-time input or by preprogramme commands from a remote workstation coupled to the CPU an located remote from the location of the robotic arm preferably on the other side of a containment or othe barrier. The workstation advantageously includes microprocessor programmed with path planner software an a user interface having a video display output and a input device. Resolvers or encoders coupled to each drive assembly, including the trolley, the gantry, the second coupling, each joint of the robotic arm, the winch, and coupled to the end effector periodically provide feedback signals corresponding to the position and orientation of each of the trolley, gantry, winch, robotic arm and end effector. The feedback signals are interpreted by the CPU using a tracker program to provide real-time, three dimensional computer simulated images on the display corresponding to the position and movement of the trolley, gantry, robotic arm, end effector, winch and other objects subject to computer control, all in relation to fixed objects located in the platform area.

According to another aspect of the invention, the track is modular. This feature enables operation of the robotic arm over a potentially large area, such as an entire containment.

It is an object of the invention to provide a remotely operated robotic system to perform a variety of tasks in a potentially hazardous environment.

It is another object of the invention to provide a robotic system and a method using the robotic system for performing health physics and maintenance tasks in a platform area near a nuclear steam generator, such as, for example, radiation surveys, air sampling, dose tracking, man-way and diaphragm removal, installation and removal of nozzle dams and channel head robotics, end effector change-outs, and bolt hole cleaning.

It is another object of the invention to provide a robotic system that can be operated from a remotely located workstation which provides real-time computer simulated images corresponding to the position and motion of the robotic system.

It is another object of the invention to provide a robotic system having a control system designed to allow tasks to be programmed with a high degree of accuracy and repeatability in order to reduce the amount of operat training necessary to operate the system.

These and other objects of the present invention wi be more fully understood from the following detail description of the invention with reference to exempla embodiments as illustrated in the drawings append hereto.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a the mechanic components of a platform server positioned between t nuclear powered steam generators according to t invention.

Figure 2 is a perspective view of an embodiment of mechanical arrangement of a platform server, including track, trolley, gantry and robotic arm system carrying radiation survey end effector.

Figure 2a is schematic elevation view of embodiment of the mechanical arrangement of a platform this invention. Figure 3 side elevation view of a portion of preferred embodiment of the invention, including straight section of track, a trolley and a gantry only.

Figure 4 is a partial sectional view through line 4- of Figure 3. Figure 5 is a top plan view of a portion of preferred embodiment of the invention, including a curv section of track, a trolley and a gantry.

Figure 6 is detail 6 from Figure 5 showing t mounting arrangement for a chain used in a drive mechani for the trolley.

Figure 7 is a section view taken through line 7-7 Figure 3, showing a rotation mechanism for the gantry.

Figure 8 is a partial sectional view through lines 8 of Figure 2a. Figures 9-14 show details of an embodiment of an e effector coupler assembly according to the invention f attaching an end effector to the robotic arm. Figure 9 is a perspective view of a of portion of a coupler on an end effector. Figure 10 is an end view of a coupler on an end effector. Figure 11 is a side view of the coupler of Figure 10. Figure 12 is an end view of a coupler on the end of the robotic arm for mating with the coupler of Figures 9-11. Figure 13 is a side view of the coupler of Figure 12.

Figure 14 is a an elevation view of an end effector storage rack according to the invention.

Figures 15, 16, 17, 18 and 19 are perspective views of preferred embodiments of a tiltable gamma and alpha radiation surveyor end effector, a swiper end effector, a roller end effector, a telescoping arm end effector, and a gripper end effector respectively.

Figure 20 is an exploded perspective view of an air sampler surveyor tool for use with the gripper of Figure 19.

Figure 21 is a perspective view of a vacuum tool for use with the gripper of Figure 19.

Figure 22 is a schematic view of the control circuit assembly of the platform server system, illustrating how a single CPU is used to control each of the trolley, the gantry, the robotic arm, and any end effector attached thereto.

Figures 23a and 23b are functional box diagrams illustrating how the encoders in the trolley and gantry drive assemblies and the resolvers in the joint assemblies of the robotic arm cooperate to control the movement of the trolley, the gantry and the arm segments of the robotic arm.

Figure 24 and 25 are perspectives views of the workstation of the control circuit assembly and a typical control display, respectively, illustrating how the system may be operated through a simple mouse-type handler.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The remotely operated managed maintenance robot system (ROMMRS) of the invention is a fully integrat robotic arm, delivered by an overhead track, trolley a gantry system, and is capable of performing multiple tas by choosing from several end effectors that can remotely attached to the robotic arm by a universal e effector coupling arrangement. The robotic arm preferably a ROSA I robotic arm providing six degrees freedom. The track, trolley and gantry provide additional two degrees of freedom for positioning the ar The system is controlled with a control circuit assemb utilizing a three-dimensional computer simulation from remote workstation that is located away from hazards human workers, such as radiation, chemical contaminatio and biological contamination, that the robotic arm near.

Referring now to the drawings, wherein structu common to each figure will be referred to by unifo reference characters throughout for simplicity exposition, and, referring in particular to Figure 1, portion of a platform server 2 is shown located betwe two nuclear powered steam generators 4, 6 (partial shown) within a containment 8. Various health physi tasks need to be performed in the area of the platform located adjacent the generators 4, 6. Some of the tas involve taking surveys of ambient air radiation level swipes of surfaces for radiation or chemical testi outside the containment 10, and monitoring of maintenan work in the platform area. Maintenance tasks inclu cleaning of bolt holes, wiping surfaces and other routi and non-routine duties. Some systems require period maintenance, such as air monitors needing filter change These tasks, typically performed by health physics a maintenance plant personnel in the past, can now accomplished by the robotic platform server 2 witho requiring plant personnel to enter the containment 8 a the concomitant exposure to radiation. The platfo server 2 is controlled from a remote location, preferably from outside the containment 8, through a control circuit to be discussed hereinafter.

Now referring also to Figures 2 and 2a, the platform server 2 includes a mechanical assembly 12 located in the containment 8 proximate the platform 10. The mechanical assembly includes a fixed, horizontal track 14 rigidly suspended above platform 10 by support structure 16. A wheeled trolley 18 is capable of controlled movement along the track 14. Depending from the trolley 18 is a gantry 20 rotatable about a vertical axis. Depending from a distal end 22 of the gantry 20 is a robotic arm 24. A variety of different types of end effectors, generally referred to by reference numeral 26, can be removably attached to a free, distal end 27 of the arm 24 with a universal end effector coupling assembly 28. The end effectors 26 are preferably stored when not in use on a rack 290 located in the area of the platform 10. The track 14, trolley 18 and gantry 20 components of the mechanical assembly provide two degrees of freedom of movement in a horizontal plane. A pan, tilt and zoom video monitor 23 for providing a video signal for remote viewing of the end effector 26 attached to the arm 24 is mounted to the gantry 20 with an video monitor mounting arrangement 27. Another pan, tilt and zoom video monitor

(not shown) can be fixed to the support structure 16 or other structure in the area of the platform 10. The robotic arm 24 is preferably structurally similar to a

ROSA I robotic system, manufactured by Westinghouse Electric Co. of Pittsburgh, Pennsylvania, that has six motorized joints 25a-25f providing six degrees of freedom of movement to the end effector 26. In one embodiment of the invention illustrated in Figure 2a, a motorized winch system 31 is mounted to the distal end 22 of the gantry for lifting objects heavier than the robotic arm 24 is capable of lifting. Electric power 102, electric signal input and output 104 and pneumatic air 106 are provided to the system through bundles 29 of cables and air tubi that follow the motion of the robotic arm 24.

Referring now also to Figures 3-5, the track 14 the preferred embodiment illustrated includes two rai 30, 32, each being preferably 1.5 inch round in cro section and spaced about a foot apart on center. T track 14 is preferably modular, wherein straight sectio 34 and curved sections 36 can each be joined to oth straight sections 34 or curved sections 36. Each straig section 34 is preferably about 38 inches long, althou other lengths can be used according to the convenience the user. Curved sections 36 are preferably about t same nominal length and can be curved either to the rig or to the left. The support structure supporting t rails 30, 32 of each modular section include triangul braces 38 spaced about a foot apart. Vertical supports rigidly connect some of the triangular braces 38 to oth rigid structures (not shown) near the steam generators 4 6. As shown in Figure 3, a mechanism for rigidly holdi separate modular sections 34 of track together can provided by a variety of fastening arrangements well kno in the art, such as, for example, toggle clamps 41.

The trolley 18 includes two wheeled trucks 42, 4 that are each rotatably coupled to a top plate 46 and base plate 48 by a set of bearings 50 and 52 respectively. The independent articulation of the truc 42, 44 enables the trolley 18 to negotiate straig sections 34 and curved sections 36 of the track 14 wi equal ease. Each truck includes an upper pair of groov top wheels 54 rolling on top of the rails 30, 32 and lower pair of grooved wheels 56 rolling on the undersi of the rails 30, 32. Each of wheels 54, 56 are preferab rubberized and include high-performance race bearings for a smooth, stable ride. A screw adjustment mechani 60 is provided for adjusting the spacing between each the upper wheels 54 and the lower wheel 56 below it. A variety of drive mechanisms can be used to drive the trolley 18 along the rails 30, 32, including direct drive via the wheels 30, 32, or indirectly with a belt drive. However, it is desirable to be able to reproducibly position the trolley within 5-10 thousandths of an inch, therefore it is preferred that an essentially all metal system having rigid components be used. In the preferred embodiment illustrated in the figures, a sprocket 62 and chain 64 drive is used. Suspended below the triangular braces 38 between the rails 30, 32 is a third rail 66 that is used for attachment of the chain. A sprocket drive assembly 67 that preferably includes an integral sprocket motor 68 and encoder 82 is coupled to the sprocket 62 by a gear reduction mechanism 70 that is fixed to the top plate 46. The sprocket motor 68 and encoder 82 used in the preferred embodiment illustrated in Figure 4 is a combination motor/encoder, such as model no. N23-54-100, available from Galil Motor Control, Inc., of Sunnyvale, California. Referring now also to Figure 6, the chain 64 rigidly supported from a third rail 72 attached to the bottom sides of the triangular braces 38. The chain 64 includes a mounting tab 74 on each roller link 76 which is attached to the third rail 72 by a fastener 78, such as a bolt. Each modular section of track 14 is assembled with a separate section of chain 64. The separate sections of chain 62 may be linked upon joining the modular sections, however it is not necessary to do so.

Mounted on top of the top plate 46, a pair of oppositely directed switches 77.1 , 77.2 provide signals that indicate when the trolley 18 has reached the ends of the track when they bump against stops 79.1 and 79.2, respectively, that are located near the ends of the track 14. A third switch 77.3 provides a signal that indicates that the trolley 18 is at a "home" position when it is switched by member 79.3. The sprocket 62 in this embodiment has 19 teeth 8 and turns about 9.5 inches per revolution. The chain 6 has a 0.50 inch pitch. The sprocket motor 68 includes encoder 82, providing 1000 counts per revolution of t motor. The gear reduction mechanism 70 provides a 50/ reduction, therefore there are 50,000 counts on t encoder 82 per revolution of the sprocket 62, or 526 counts per inch of travel along the track 14, providing theoretical positional resolution of the trolley 18 less than about two ten thousandths of an inch. Encode having a capacity of about six million counts a currently available. Therefore, the track 14 can extended by adding additional track modules 34,^" 36 to total length of about 100 feet while retaining the sa positional resolution.

It will be appreciated that the track and troll system can be designed for almost any configuration. I can be configured to go around corners with the additio of curved sections of track. Even without the roboti arm, the track and trolley system can be adapted t deliver any type of monitoring device. The addition o bus bars to the track to supply power to equipment bein delivered by the trolley, thereby freeing the system o cables, is also encompassed by the invention. A proximate end 81 of the gantry 20 is preferabl attached to the base plate 48 of the trolley 18 by quick-disconnect coupling 83, which is shown in cros section in Figure 7. The quick-disconnect coupling 83 ma be provided by a dovetail joint assembly having a femal plate 84 mounted to base plate 48, a mating male plate 8 attached to a dovetail joint assembly flange 88, and locking arrangement 90 for releasably holding the male a female plates together. The dovetail joint assembl flange 88 is coupled to a stationary disk 92 of a gant motor assembly 94 that provides rotation of the gantry 2 about a first vertical axis 95.1. The locking arrangeme 90 in this embodiment includes a rotatable lock bar 90. extending through the female plate 84 transverse to a direction of movement of the male plate 86. The lock bar 90.1 includes a pair of radially extending tabs 90.2 that engage with slots 90.3 when the lock bar 90.1 is turned by handles 90.4. In addition, the locking arrangement may include a pin removably inserted through aligned holes extending through the male plate 86 and the female plate 84 (not shown) or other known locking mechanisms.

The gantry 20 is preferably a rectangular-shaped, mostly hollow structure having several internal ribs (not shown) for structural strengthening. A movable housing 96 is defined by the gantry 20. Disposed within an interior space defined by both of the disk 92 and housing 96 is an electric motor 98. Preferably, the electric motor is a brush-type, permanent magnet d.c. motor which may be, for example, model no. QT-3810A available from the Endland Motor Subsidiary of Kollmorgan Corporation located in Radford, Virginia. The electric motor 98 is contained within a cup-shaped motor housing 110 which is supported within the stationary 96 housing by means of a motor frame 112. The motor frame 112 includes a tubular support member 114 which is concentrically aligned with the axis of rotation of the motor 98, as well as a plurality of bracket members 116.1, 116.2 which support the stator ring 118 of the motor 98. More specifically, the stator ring 118 is connected to the distal ends of the bracket members 116.1, 116.2 by means of screws 120.1, 120.2. Mounting bolts 122 in turn secure both the motor frame 112 and the motor housing 110 to the movable housing 96. The rotor 124 of the electric motor 98 is rotatably supported by the tubular support member 114 of the motor frame 112, and is closely spaced to the inner periphery of the stator ring 118. A pair of annular bearings 126 minimize the frictional contact between the outer surface of the tubular support member 114 and the inner periphery of the rotor 12 . The inner periphery of the tubular support member 114 defines a cylindrical space 128 which houses an encoder 130 capable of generating an electrical sign indicative of changes in the angular position of t movable housing 96 relative to the stationary disk 92 The encoder may be a model E116-1024-1 available from B Motion Systems Co. of San Marcos, California.

The rotor 124 of the electric motor 98 does not dri the movable housing 96 relative to the stationary disk 9 directly, but only through a harmonic drive assembly 13 contained within the disk 92 and housing 96. To this en the rotor 124 includes a locking tab 134 which is engag within a slot in the drive disk 136 of the harmonic dri assembly 132. On the inner surface of the drive disk 136 an oil splash flange 138 is provided. A plurality of bal bearings 140 (of which only two are shown) , are rotatabl received within a plurality of spherical indentatio present around the periphery of the drive disk 136. The ball bearings 140 rotatably engage a flexible spline ri 142 whose outer periphery engages the inner periphery o the cup-shaped motor housing 110 such that the rotation the drive disk 136 causes the ball bearings 140 t flexibly deform the periphery of the housing 110 by th action of the ball bearings 140. Disposed around th periphery of the cup-shaped motor housing 110 are plurality of small, cog-like teeth (not shown) . Thes teeth engage another set of small, cog-like teeth prese around the inner periphery of an outer drive ring 144 suc that the flexure of the teeth present on the oute periphery of the motor housing 110 induces a rotation o the outer drive ring 144. Because this drive ring 144 i connected to the stationary disk 92 by means of mountin bolts 146, the housing 96 rotates relative to th stationary disk 92. To facilitate such rotation, a pai of annular ball bearing assemblies 148.1, 148.2 a disposed between the inner cylindrical wall of the movabl housing 96, and an outer support wall 150 which i connected to the stationary disk 92 by the same bolts 14 that secure the outer drive ring 144 to the disk 92. annular spacer 152 separates the bearing assemblies 148.1, 148.2. In the preferred embodiment, the harmonic drive assembly is a model no. HDC-4M-2A-SP manufactured by the Harmonic Drive Division of USM corporation located in Wakefield, Massachusetts.

The encoder provides 4096 bits of resolution per rotation of the motor. The harmonic drive provides a 200/1 reduction between the rotation of the rotor 124 and the rotation of the stationary disk 92, therefore there is a theoretical resolution of almost 8.2 million bits per rotation relative to the stationary disk 92. The gantry is preferably 43.875 inches long between the axis of rotation of the gantry 20 and its distal end 22, therefore the positional resolution of distal end 22 is theoretically about .034 thousandths of an inch.

The video monitor 23 is suspended below the gantry 20 by the video monitor mounting arrangement 27 that includes a quick-disconnect connection 154 that may be provided by a dovetail joint. A female member is mounted to the underside of the movable housing 96. A male plate 156 mating with the female member 154 can be locked in place by a locking mechanism 158 structurally similar to locking mechanism 90.

The structure of the robotic arm 24 is preferably provided by a modified ROSA I robotic arm manufactured by Westinghouse Electric Corporation of Pittsburgh, Pennsylvania. The ROSA I system is described in U.S. Patent No. 4,196,049, incorporated herein by reference. The system includes six rotation joint assemblies 25.1- 25.6 connecting five arm segments 160.1-160.5. The ROSA I system is modified in that the brake in each joint assembly is removed to reduce the weight of the arm and to increase its lifting capacity. The first joint assembly 25.1, located at a proximate end 162 of the robotic arm 24, connects between a second quick-disconnect coupling 164 on the underside of the distal end 22 of the gantry 20 and the first arm segment 160.1. The second quick- disconnect coupling 164 is preferably structurally simil to quick-disconnect coupling 83. The first joint assemb 25.1 provides rotation of the first arm segment 160 about a second vertical axis 95.2. The second joi assembly 25.2 coupling between the first arm segment 160. and the second arm segment 160.2 provides rotation of t second arm segment 160.2 about a first horizontal ax

166.1. The third joint assembly 25.3 coupling between t second arm segment 160.2 and the third arm segment 160 provides rotation of the third arm segment 160.3 about second horizontal axis 166.2 parallel to the fir horizontal axis 166.1. The fourth joint assembly 25. coupling between the third arm segment 160.3 and t fourth arm segment 160.4 provides rotation of the four arm segment 160.4 about a third horizontal axis 166 parallel to the first and second horizontal axes 166.

166.2. The first, second, third and fourth arm segmen 160.1-160.4 define a common plane that is rotated arou the second vertical axis 95.2 by the first joint assemb 25.1. The fifth joint assembly 25.5 coupling between t fourth arm segment 160.4 and the fifth arm segment 160. provides rotation of the fifth arm segment 160.5 about first wrist axis 168.1 that is in the common plane a transverse to the fourth arm segment 160.4. The six joint assembly 25.6 coupling between the fifth arm segme 160.5 and the end effector coupling assembly 23 provid rotation of the end effector coupling assembly 23, and end effector 26 that may be attached thereto, about second wrist axis 168.2 collinear with the fifth a segment 160.5.

The mechanism and operation of each of the joi assemblies 25.1- 25.6 is functionally uniform a structurally similar. The structure of each of joi assemblies 25.1-25.3 are similarly sized. Joi assemblies 25.4-25.6 are also similarly sized, but small than assemblies 25.1-25.3. Each of the joint assembli 25.1-25.6 has many similarities to the gantry dri assembly 94 illustrated in Figure 7. Figure 8 illustrates in partial, cross sectional view a typical joint assembly, generally indicated by reference character 25. A primary difference between joint assembly 25 and the gantry drive assembly 94 is that the encoder 82 is replaced with a frameless, dual speed, pancake-type resolver 200. Similar to the gantry drive assembly 94, joint assembly 25 includes a stationary disk 202 and a movable housing 204 defining a generally cylindrically shaped space therebetween. Disposed within the interior of the housings 202, 204 is an electric motor 206. The electric motor 206 used in each of the joint assemblies of the robotic arm 24 is a brush-type, permanent magnet d.c. motor which may be, for example, model no. QT-3802 for the larger assemblies 25.1-25.3 and model no. QT3102 for the smaller assemblies 25.4-25.6, available from the Endland Motor Subsidiary of Kollmorgan Corporation located in Radford, Virginia. The electric motor 206 of each of the joint assemblies is contained within a cup-shaped motor housing 208 which is supported within the stationary disk 202 by means of a motor frame 210. The motor frame 210 includes a tubular support member 212 which is concentrically aligned with the axis of rotation of the motor, as well as a plurality of bracket members 214, which support the stator ring 216 of the motor. Mounting bolts 218 secure both the motor frame 210 and the motor housing 208 to the stationary disk 202. The rotor 220 of the electric motor 206 is rotatably supported by the tubular support member 212 of the motor frame 210, and is closely spaced to the inner periphery of the stator ring 216. A pair of annular bearings 222 minimize the frictional contact between the outer surface of the tubular support member 212 and the inner periphery of the rotor 220. Power is brought to the motor 206 and harmonic drive assembly 224 via a wire bundle 221 running in through a first cable connection 223. As with the gantry drive assembly 94, rotatabl housing 204 of each joint assembly is driven indirectl through a harmonic drive assembly 224 contained within th housings 202, 204. The coupling between the motor 206 the harmonic drive assembly 224 and the housings 202, 20 is functionally similar to the coupling between the gantr motor 98, the gantry harmonic drive assembly 132, and t gantry drive disk 92 and housing 96. The rotor 22 includes a locking tab 226 which is engaged within a slo in the drive disk 228 of the harmonic drive assembly 200 On the inner surface of the drive disk 228, an oil splas flange 230 is provided. A plurality of ball bearings 23 (of which only one is shown) , are rotatably receive within a plurality of spherical indentations prese around the periphery of the drive disk 136. These bal bearings 232 rotatably engage a flexible spline ring 23 whose outer periphery engages the inner periphery of th cup-shaped motor housing 208 such that the rotation of th drive disk 228 causes the ball bearings 232 to flexibl deform the periphery of the housing 208 by the action o the ball bearings 232. Disposed around the periphery o the cup-shaped motor housing 208 are a plurality of small cog-like teeth (not shown) . These teeth engage anothe set of small, cog-like teeth present around the inne periphery of an outer drive ring 236 such that the flexur of the teeth present on the outer periphery of the moto housing 208 induces a rotation of the outer drive rin 236. Because this drive ring 236 is connected to th rotatable housing 204 by means of mounting bolts 238, th housing 204 rotates relative to the stationary disk 202 To facilitate such rotation, a pair of annular bal bearing assemblies 240 are disposed between the inne cylindrical wall of the stationary disk 204, and an oute support wall 242 which is connected to the rotatabl housing 204 by the same bolts 238 that secure the oute drive ring 236 to the housing 204. An annular spacer 24 separates the bearing assemblies 240. In the preferr embodiment, the harmonic drive assembly 200 for joint assemblies 25.1-25.3 is a model no. HDC-4M-200-2BL, and for joint assemblies 25.4-25.6 is a model no. HDC-2M-200- 2BL, each manufactured by the Harmonic Drive Division of USM Corporation, located in Wakefield, Massachusetts.

The inner periphery of the tubular support member 212 defines a cylindrical space which houses the resolver assembly 200, which is capable of generating a position signal indicative of changes in the angular position of the rotatable housing 204 relative to the stationary disk 202. In the preferred embodiment, the resolver may be a frameless, dual speed, pancake-type resolver, such as, for example, model no. SSJH-31-P-3, available from Clifton Precision of Clifton Heights, Pennsylvania. This type of resolver includes an XI resolver which provides a XI sine wave signal indicative of the number of rotations of the rotatable housing 204 relative to the stationary disk 202 with one period per rotation, and a X32 resolver which provides a X32 sine wave signal indicative of the angular position of the movable housing 204 relative to the stationary disk 202 with 32 periods per rotation. The resolution of the XI resolver is 65,536 bits/rotation. The X2 resolver provides a 32 fold increase in resolution, therefore there is a theoretical resolution of almost 2.1 million bits per rotation of each joint assembly 25. The position signal actually comprises a reference signal, a sine signal and a cosine signal from each of the XI and X32 resolvers.

The resolver assembly 200 includes a housing 244 fastened to the movable housing 204 with bolts 245. Power and signal lines are brought in via wire bundle 246 through cable connection 248. A stationary portion of the resolver, including a flexible bellows 250, support ring 252, and stationary XI coil 254 and stationary X32 coil 256 on annular disk 257, is fixed to the motor frame 210 at a slotted connection 258. A movable portion of the resolver 200 includes a tubular support 259 connected to housing 244, movable XI coil 260 and a movable X32 co 262 on support ring 264. A pair of annular beari assemblies 266 permits low friction rotation of tubul support 259 within support ring 252. With reference now to Figures 9-13, the end effect coupling assembly 23 includes a first end effector coupl 270 (Figures 12-13) on the distal end of the robotic a 24 and a mating second end effector coupler 272 (Figur 9-11) on each of the end effectors 26 by means of whi electric power, control signal and pneumatic air delivered to an end effector 26 through make and bre connections.

The second end effector coupler 272 includes an op sided frame 274 having a octagonal front end plate 276 a a octagonal back end plate 278 spaced apart by four spac side plates 280. A tool hangar assembly 282 attached one side of the frame 274 includes a rectangular-shape open box 284 and a spacer 286. The open box 284 fits ov a mating rectangular-shaped structure 288 on an e effector storage rack 290 illustrated in Figure 14 us for storing each end effector 26 when not in use. A ma coupling plate 292 is mounted on the front end plate 2 by bolts 294. Dowel pins 295 projecting from back e plate 278 may be used for aligning with an end effector during assembly.

Pneumatic air or vacuum is brought into the coupli plate 292 through openings 298 on an exposed face 300 the coupling plate 292. The openings 298 connect wi threaded side ports 296 into which air or vacuum fittin 302 may be connected. Flexible hoses 304 connected fittings 302 bring the air or vacuum to solenoid actuat valves 306 located within the frame 274. Valves 306 ea include an input port 308 connecting to one of the lin 304 and an output port 310 that may be coupled to actuator or other air or vacuum operated device (n shown) on the end effector 26. Electric power, preferably 24V, and signal lines are brought to the end effector 26 via multi-pin male electrical connector 312, which includes an electric connector plate 314 that is removably fastened to coupling plate 292. The electrical connector plate 314 preferably may be molded or machined from an insulating material to electrically isolate a plurality of male electric connector pins 316, projecting from an exposed face, from each other. If a metal is used to fabricate plate 314, then insulating isolators (not shown) should be used for mounting each pin 316. Each pin 316 is connected to a conductor line (not shown) which in turn connects to a pin of a commercially available first connector 318, such as the 15 pin "D" connector illustrated in the Figures or another suitable type of multi-pin connector. First connector 318 is fastened to plate 314 with screws 320. A second connector 321 mating with first connector 318 connects to conducting wires 322 for electrically connecting to electrical devices located in the frame 274, such as digital i/o device 324 and valves 306, and any other devices that may be incorporated into a particular end effector 26, such as, for example, motors, radiation sensors and other devices (not shown) . The digital i/o device 324 preferably includes an RS232 communications connection, such as, for example, model no. D1711, Available from Omega, Inc. of Stamford, Connecticut.

The first end effector coupler 270 includes a female coupling plate 326 that mates with structure located on the male coupling plate 274. The female coupling plate 326 is fastened with bolts 327 to an annular back plate 328 having a first flange 330 that in turn connects to a tubular spacer 332 having a second flange 334 connection to the movable housing 204 of the sixth joint assembly 25.6 of the robotic arm 24. Tubular spacer includes a port 333 through which an electric cable 335 may be brought for providing electrical power and signal connections to the resolver 200 of the sixth joint assembly 25.6

Female coupling plate 326 includes a multi-wire female electrical connector 336 similar in most respects to connector 312. Connector plate 338 is fastened to coupling plate 326 by screws or bolts 340, and includes preferably fifteen conducting female sockets 342 aligned for insertion of pins 316. Sockets 342 are electrically connected to a multi-wire first connector 344, such as a "D" connector. A second connector 346 mating with first connector 344 can be used for bringing power and signal connections to first connector 344 through multi-wire cable 348.

Pneumatic air and vacuum connections on the female coupling plate 326 are structured similarly to those on the male coupling plate 274. Air (or vacuum) is brought in via hoses 350 connecting to fittings 352 attached to ports 354. Ports 354 connect through channels 356 in the coupling plate 326 to openings 358 at the surface of coupling plate 326 aligned with openings 298. Resilient o-rings 360 seated in o-ring grooves around openings 358 resist air or vacuum leaks when the female coupling plate 326 is joined to the male coupling plate 274.

The male and female coupling plates 274, 326 are preferably tool plate model no. 56060-1-2001, available from PHD, Inc., located in Fort Wayne, Indiana. The coupling plate 274 includes a ball detent 362 that fits in a mating spring-loaded detent fitting 364 in the female coupling plate 326. An air and vacuum connecting to the detent fitting 364 are used for positively retaining or ejecting the detent 362 from the fitting 364. Alignment pins 366 projecting from the male coupling plate 274 and aligned with mating holes 368 defined by the female coupling plate 326 ensure proper air and electrical connections.

Arrayed around the first end effector coupling 270 are four radiation sensors 370 supported by articulating arms 372 fastened to flange 330. Each sensor transmits an electric signal indicative the ambient radiation level that it senses by means of an electric cable 376 to an transmitter 374 that is attached to the robotic arm 24. The transmitter 374 transmits a wireless electromagnetic wave signal indicative of the radiation level sensed by each sensor 370 to a remote receiver 558. The four sensors can be used to map the activity level in the platform area. Also arrayed around the first end effector coupling are three fixed lens video monitors 378 (only shown in Figure 12) used for close visual observation in the platform area, monitoring attachment and removal of an end effector 26 and monitoring operations performed by an attached end effector 26. The video monitors 378 may be attached to flange 330 by an articulated arm 380 or other convenient arrangement.

Referring now also to Figures 14-21, an end effector storage rack 290 is shown storing a variety of end effectors and attachments, including a tiltable gamma and alpha radiation surveyor end effector 26.1 (Figure 15), a swiper end effector 26.2 (Figure 16), a roller end effector 26.3 (Figure 17), a gripper end effector 26.5 (Figure 19) , an air sampler canister 390 (Figure 20) , and a vacuumer 392 (Figure 21) . A telescoping arm end effector 26.4 (Figure 18) and other types of end effectors 26 can also be stored on the rack 290. The rack 290 includes a frame 394 that sits on the platform 10 or other area within reach of the robotic arm 24. Projecting from the frame 394 are several rectangular hangars 396.1-396.6 for placement in the rectangular-shaped opening 284 of end effectors 26.1-26.5 and vacuumer 392, respectively. There are also several round tube hangars 398 projecting from the frame 394 for holding a like number of air sampler canisters 390. Storage space is also provided by an attached rack 400 for other items, such as, for example, hand tools and spare parts. Several end effectors have been designed to perform a variety of health physics tasks in a nuclear power facility. Survey end effector 26.1 includes a Geiger- Mueller sensor 402 for detecting gamma and beta radiation and providing an electric signal indicative of the radiation level. Sensor 402 is mounted on a frame 404 that includes a swivel joint 406 so that the sensor 402 can be tilted by actuator 408. Sensor has a display 410 that can be remotely viewed via one of the video monitors 378.

Swiper end effector 26.2 includes several pads 412 attached to a belt 414 that can rotate on rollers 416. The pads pick up samples of dust, particulates, or liquid as the belt 414 rolls on a surface (not shown) . The pads can then later be tested for radioactivity or other types of contamination.

Roller end effector 26.3 includes a roller assembly 420 structurally similar to a paint roller, but having a tacky surface 422 for picking up particulates which may be radioactive or that may include hazardous chemicals.

Telescoping arm end effector 26.4 having an extensible end 430 is used for surveying areas where the surveyor end effector 26.1 cannot reach. Radiation sensors 432 or video monitors (not shown) can be attached near the end 430 for this purpose.

Gripper end effector 26.5 includes three radially movable arms 440 for gripping, in particular, air sampler canisters 390 and the vacuum attachment 392.

Air sampler cartridge 390 is part of an air sampler system 450 that also includes a mounting bracket 452 adapted for clamping to a pipe or other structure (not shown) . Air sampler cartridge 390 includes a tubular male fitting 454 that removably attaches to female fitting 456 in bracket 452. Bracket 452 has a nipple 458 for a vacuum hose connected to fitting 456 by an internal channel.

When cartridge 390 is inserted into bracket 452, the vacuum draws air through filter 460 at the other end of the cartridge, which is adapted for gripping by the gripper 26.5.

Vacuum attachment 392 includes a tube having a fitting 472 for a vacuum hose (not shown) , a flexible bellows 474 and a vacuum nozzle 476. An arm 478 projects from a side of the tube 470. The arm 478 includes an end 480 adapted for gripping by the gripper 26.5. the arm 478 also includes a hooked branch 482 for hanging in a hangar 484. With reference now to Figure 22, the control circuit assembly 498 of the invention includes a power filter 500 for eliminating "spikes" in the 480 volt, three phase alternating current received locally from the utility. The resulting, "smoothed" power is transmitted through a breaker in the power filter 500 by way of an electric cable 502 into containment 8. The output of the main power filter 500, which is also a distribution box, is connected to a local transformer circuit 504 located in the containment 8 near the platform 10 for converting the 480 volt, three phase power to 120 volt single phase power. Local transformer circuit 504 also acts a distribution box, distributing this power to a junction box circuit 506 via cable 508, to an audio power supply circuit 510 via cable 512, and to a video power supply circuit 514 via cable 516. The power from power filter 500 is also distributed by way of an electric cable 518 to a robot transformer circuit 520 that converts the 480 volt, three phase current received from the main power filter 500 into 48 volt, single phase current suitable for powering a robot amplifier circuit 522 by means of cable 523.1. Cable 523.2 brings 120V power to control circuitry within robot amplifier circuit 522. The robot transformer circuit 520 also connects to a CPU circuit 524 by means of a multi-component cable 525, and to a universal I/O circuit 526 by cable 527. E-stop cable 528 is provided between the robot amplifier 522 and an emergency stop circuit 529, located in the vicinity of a workstation 530, for shutting down the trolley 18, gantry 20 and robotic arm 24 in the event of a CPU malfunction.

A communications cable 531 interconnects the workstation 530 and the CPU circuit. An Ethernet^® cable is preferred for this particular link-up since it is capable of transmitting over ten megabits of information per second, and since there is a large volume of informational exchange between the workstation 518, and the trolley/gantry/robotic arm system 18, 20, 24 and the I/O controller 520. The workstation 530, a main viewing a/v console 532, an operations a/v console 534, and a remote viewing a/v console 536, which are typically located remote from the platform 10 and preferably outside the containment 8 in an area referred to as an operations trailer 538, are powered from a second local transformer 540 via cables 542, 544, 546 and 548 respectively. Cables 535.1 and 531.2 connect between the operations a/v console 534 and the audio power supply circuit 510 and video power supply circuit 514, respectively. Communications cable 549 couples together robot amplifier circuit 522 with CPU circuit 524. A multi- component cable 550 interconnects the output of both the robot amplifier circuit 522 and the CPU circuit 524 to the electric motors of each of the six motorized joint assemblies 25.1-25.6 of the ROSA I robotic arm 24. This same cable further connects the outputs of the XI and X32 resolvers of each of the motorized joint assemblies to the input of the CPU circuit 522. Cable 550 also connects the CPU circuit 524 to the end effector coupling 28 for supplying a high speed data acquisition interface with any end effector 26 disposed on the distal end of the robotic arm 24.

The CPU circuit 524 communicates with the universal I/O circuit 526 via cables 552.1, 552.1, and the junction box circuit 506 via cables 554.1, 554.2. The universal I/O circuit 526 communicates with the junction box circuit 506 via cable 556. The junction box circuit 506 is connected for power and signal to receiver 558 by cable 557, and to a platform junction box circuit 560 by cables 562, 564. The junction box circuit 506 is designed to intercept signals from almost all devices and instruments on the platform except for^'the robotic arm 24, and reroute them to the appropriate place. It contains two amplifiers and associated buss power equipment to power the trolley assembly 18, the gantry assembly 20, and the winch 31. It also houses pneumatics for the end effector coupling assembly 270 and supply air for various end effectors 26. The platform junction box circuit 560 transfers power from junction box circuit 506 to the motors of the drive assemblies of each of the trolley assembly 18, the gantry assembly 20, and the winch 31, and receives signals indicative of the position of each from the encoder incorporated in those assemblies via multi-component cables 566, 568 and 570, respectively.

The audio power supply 510 is wired to an audio user station 572 located on the platform 10 by cable 574. The video power supply 514 is wired to the pan, zoom and tilt

(PZT) video monitor 23 located on the gantry assembly 20 by cable 576, and is also wired to another, fixed location, PZT video monitor 578 in the platform area 10 by cable 580. The video cameras 378 (only two shown in Figure 22) located on the first end effector coupler 270 is connected for power and signal to the video power supply by cables 582.

Finally, the control circuit assembly 498 includes a source of moving air in order to cool the various components of the system. Accordingly, a filtered cooling air dryer 584 is provided for removing particulate matter and moisture from the air circulated through the robotic arm 24, the robot amplifier circuit 522 and the CPU circuit 524 located in containment 8. It should be noted that the vast majority of the components of the control circuit assembly 498 are designed to be quickly set-up and taken down within the containment wall of the utility. Specifically, robot transformer 520, local transformer 504, robot amplifier circuit 522, CPU circuit 524, universal I/O circuit 526, cooling air drier 584, junction box circuit 506, platform junction box circuit 560, Audio power supply circuit 510, and video power supply circuit 514 are each contained within a portable modular housing, and the various cables that interconnect these housings are of the quick- disconnect type to allow these components to be easily carried within the containment wall, and assembled in an area close to the vicinity of the channel head of the steam generator. Such a portable, modular construction that is easily assembled behind the containment wall advantageously minimizes the number of penetrations through the containment area to only two (i.e., one for the power cable 502, and a second from the trailer 538 for the Ethernet cable 531, and operations a/v console cables 535.1 and 535.2, and the emergency stop cable 528) . Additionally, a decontaminatable cover (not shown) is provided for each of the components of the control circuit assembly designed to be carried into and setup within the containment area of the utility. In practice, these covers may have a structure as simple as that of a plastic bag. Of course, the purpose of such covers is to facilitate the decontamination of each of these components when they are removed from the containment area of the utility.

The method employed by the control circuit assembly may best be understood with reference now to Figures 23a, 23b, 24 and 25. Figure 23a refers to the control of the motor drives of the trolley assembly 18, the gantry assembly 20 or the winch 31. Figure 23b refers to the control of the motor drives of each joint assembly on the robotic arm 24. These figures illustrate in schematic form the functional relationships between these motor drives and workstation 530, CPU circuit 524, power delivered through junction boxes 506 and 560 or the robot amplifier circuit 522.

With specific reference to Figures 24 and 25, the workstation 530, which is preferably a model Indigo 2 computer manufactured by Silcon Graphics, Inc., located in Mountainview, California, configured with ROBCAD software. Such a workstation has a microprocessor 600, path planner software 602, and a user interface 604 advantageously formed from what may be described as a digital three- button mouse teleoperation 606, which replaces the standard analog joystick arrangement associated with the prior art.

With this interface, the operator makes can make selections from the display 608 on the interface crt tube 610 illustrated in Figure 24. A typical display is illustrated in Figure 25. Most of the display screen 608 shows a real-time computer simulated image 612 of the environment of the mechanical components of the platform server, including the track 14, trolley assembly 18, gantry assembly 20, robotic arm 24, end effector 26, and various objects in the platform area. Text 614 describing a variety of functions is arrayed around the image. Specifically, to pick a text selection, the operator slides the mouse 614 on the pad 616 until the arrow 617 on the display 608 is over the text describing the desired selection, and then presses a mouse button 618. Plus and minus direction moves are then made by using the right 620 and middle 622 buttons of the mouse 616. Velocity control end point motion with mouse speed selection maintains the intuitive feel of a joystick operation, at a substantially lower cost.

Alternatively, the operator can move the robotic arm 24 and end effector 26 across the image on the display with the mouse, and the workstation will plan a path for each component of the system to achieve the desired result with the physical system without collisions. This is possible because the workstation 530 is programmed with positional information for each object in the area of the platform 10, and therefore can plan a path that avoids these potential collision hazards.

The workstation system is capable of learning tasks by storing movements that are manually input into a task control program. These tasks can then be repeated by inputting a simple mouse command to run the control program.

With reference again to Figures 23a and 23b, the microprocessor 600 of the workstation 530 is programmed with the path planner software 602. The purpose of the path planner is to convert generalized direction commands

(for example, "move distal end of robotic arm from tube location 3A to 6F") into eight degree vectors (including x, y, and z Cartesian axes and roll, yaw and pitch for the robotic arm 24, and trolley position and gantry angle) which will be understandable to the trolley, gantry and robotic arm kinematics software that is present within the path control section of the CPU circuit 524. It should be noted that the path planner 602 "knows" the possible universe of trajectories (i.e., trajectories which avoid collisions between the arm and objects in the platform area, or the arm and an end effector) when it performs its functions of converting the generalized commands given by the operator of the workstation 530 into specific, degree vectors.

Turning now to a functional description of the CPU circuit 530, the specific vector instruction information relayed to the CPU circuit 530 is next converted into a specific set of vectors, comprising the trolley position, the gantry angle and the angles of the joint assemblies, by the interaction of the central processing unit (CPU) 620 of the CPU circuit 524 and a robot kinematic software package designated as path control 622. The CPU 620 is preferably a model number HK68/V30 computer manufactured by Heurikon Corporation located in Madison, Wisconsin. The CPU of the CPU circuit 524 then periodically transmits an actuation signal through a motor motion control card 624 which in turn modulates the power conducted to the motors 68, 98, 206 of the trolley assembly 18, gantry assembly 20 or a joint assembly, respectively, to achieve the desired trajectory. One motor motion control card 624, along with an A/D converter 628, is located in the universal I/O circuit 526 for the trolley and gantry control (Figure 23a) . In the case of the joint assemblies 25, an A/D converter 630 digitizes an analog XI position signal from the resolver 200 and transfers that signal to a second motion control card 624 located in the CPU circuit 524 (Figure 23b) . The motor motion control card 524 is preferably a microprocessor based model no. DMC-530 motion control card, available from Galil Motor Control, Inc., of Sunnyvale, California. For the joint assemblies 25, a second A/D converter 532 digitizes a X32 signal from the resolver 200 and provides this signal to the tracker 626.

Before transmitting its command signals to the motor motion control card 624, the CPU 620 processes information from tracker software 626 whose purpose is to inform the CPU 620 as to which specific increment of the robotic kinematics associated with the desired trajectory has been complete. The tracker 626 is able to perform this function by receiving what amounts to a feedback signal from, in the case of the trolley assembly 18 or gantry assembly 20, the encoder 80 or 130, respectively, or, in the case of the joint assemblies 25, two feedback signals, one from each of the XI and X2 resolvers, which, as has been indicated earlier, is determinative of the angle that the joint has turned, the feedback signals are converted into 16 bit digital signals by digital converters 628, 630 and 632 to render them in a form which can be processed by the tracker software 626. In operation, the CPU 620 interacts with the path control 622 and tracker software 626 in the following manner. First, the path control software 622 informs the CPU 620 of the series of incremental steps of trolley, gantry and robotic arm kinematics necessary to achieve a desired trajectory. It transmits this information to the CPU every 50 milliseconds. By contrast, the tracker software 626 informs the CPU 620 when a particular increment in the series of kinematic commands has been completed. It transmits this information to the CPU 620 every ten milliseconds. The motor motion control cards 634 converts every increment of the kinematics into specific electric power commands to the -motors 68, 98, 206 which determines the speed and amount of motor shaf rotation for each. The CPU 620 will tell the motor motion control cards 624 to change the motor power commands that it generates only when the tracker 626 has informed the CPU 620 that a particular increment of the kinematics has been achieved. Of course, the relatively low power digital signals generated by the motor motion control cards 624 must be converted back to analog signals to properly modulate the pulse-type d.c. power conducted through the motors 68, 98, 206 by the amplifiers in the junction box circuit 506 and the robot amplifier circuit 522.

It will be appreciated that ROMMRS is a versatile system that, while particularly useful for servicing present power reactor facilities and advanced reactor designs, can also be configured for use in a variety of other hazardous environments. Its modular track design, a reliable robotic arm capable of delivering custom designed end effectors, and a computer control system allowing easy performance of simple as well as complex tasks with minimum operator experience, permits maximum user flexibility.

Whereas particular embodiments of the present invention have been described above as examples, it will be appreciated that variations of the details may be made without departing from the invention. Therefore, reference should be made to the appended claims rather than to the foregoing discussion of preferred examples, in order to assess the scope of the invention in which exclusive rights are claimed.

Claims

WE CLAIM :

1. A robotic system for manipulating an end effector, comprising: an elevated track assembly, including a track; a trolley assembly suspended from the track; trolley drive means for moving the trolley along the track; a gantry assembly, including a horizontal gantry and gantry drive means for rotating the gantry about a first vertical axis; a gantry coupling assembly for attaching the gantry drive means to the trolley assembly; an articulated robotic arm, including a plurality of motorized joint assemblies for cooperatively moving a distal end of the arm, wherein a first joint assembly provides rotation of the distal end of the arm about a second vertical axis; a robotic arm coupling assembly for attaching a proximate end of the robotic arm to the gantry,* universal end effector coupling means for removably attaching the end effector to a distal end of the robotic arm, including air connection means for providing pneumatic air to the end effector, electric connection means for providing electric power to the end effector and for coupling an electric signal line to the end effector; and a control circuit assembly for remotely controlling each of the trolley drive means, the gantry drive means, each of the joint assemblies of the robotic arm, attachment and detachment of the end effector and the end effector when the end effector is attached to the robotic arm.

2. The robotic system of claim 1, wherein the control circuit assembly includes first video monitoring means attached to the gantry for providing a first remote video image, comprising means for panning around a vertical axis, for tilting about a horizontal axis and for enlarging the first remote video image.

3. The robotic system of claim 1, wherein the control circuit assembly includes second video monitoring means fixed to the distal end of the robotic arm for providing a second remote video image of an area in front of the distal end of the robotic arm.

4. The robotic system of claim 1, wherein the control circuit assembly includes first radiation survey means on the distal end of the robotic arm for providing a first radiation survey signal indicative of an ambient radiation level in the vicinity of the distal end of the robotic arm.

5. The robotic system of claim 4, wherein the first radiation survey means comprises a plurality of first radiation sensors spaced apart around the distal end of the robotic arm each providing a first radiation sensor signal indicative of a local ambient radiation level in the vicinity of each, and wherein the first radiation survey signal is indicative of each local ambient radiation level.

6. The robotic system of claim 1, wherein the end effector coupling means comprises a first end effector coupler on the distal end of the robotic arm, a second end effector coupler on the end effector, each of the first and second end effector couplers including a coupling plate defining alignment structure mating with the alignment structure on the other, wherein the air connection means comprises an air valve on the second end effector coupler for controlling pneumatic air provided to a pneumatic device on the end effector and the electric connection means comprises a digital communication device on the second end effector coupler for coupling an electric device on the end effector to the control circuit assembly.

7. The robotic system of claim 1, wherein the track assembly comprises a plurality of modular sections, the plurality of modular sections including a straight section and an arcuate section, each modular section comprising a pair of uniformly spaced rails connected by transverse braces extending therebetween, the track assembly being fixed in an elevated horizontal plane by track support structure attached to the braces.

^' 8. The robotic system of claim 7, wherein the trolley drive means comprises: a sprocket assembly attached to the trolley, including a sprocket having a plurality of teeth, an electric sprocket motor coupled to the control circuit assembly, a gear reducer coupled to the drive shaft of the sprocket motor for rotating the sprocket such that a turn ratio of the sprocket to the sprocket motor drive shaft is less than one, and sprocket feedback means coupled to the control circuit assembly for providing a sprocket position signal indicative of an angular position of the sprocket; and a fixed section of chain, including uniformly spaced vertically oriented links, located between the rails and supported from the brace members and engaging the teeth of the sprocket such that rotation of the sprocket effects movement of the trolley along the track.

9. The robotic system of claim 8, wherein the control circuit assembly includes: track end means for providing an end signal when the trolley is proximate an end of the track; and trolley position reference means for providing a signal indicative that the trolley is at a known reference position.

10. The robotic system of claim 8, wherein the trolley comprises a base plate coupled to the gantry coupling assembly and a pair of wheeled carriages, each wheeled carriage including coaxial first and second wheels riding on the first and the second spaced rails respectively, the first and second wheels being coupled together by an undercarriage, each of the undercarriages being freely rotatably coupled to the base plate about a different vertical axis, whereby the trolley can move along each of the straight section of track and the arcuate section of track.

11. The robotic system of claim 10, wherein each wheeled carriage includes coaxial third and fourth wheels rolling below the first and the second spaced rails respectively, directly below the first and the second wheels respectively, and coupled together by the undercarriage, and wheel adjustment means for adjusting the spacing between the first and third rails and between the second and fourth wheels.

12. The robotic system of claim 1, wherein the gantry coupling assembly and the robotic arm coupling assembly each are quick-disconnect couplings.

13. The robotic system of claim 1, wherein the end effector is selected from a member of the group consisting of: a gamma and beta radiation sensor monitor; a grasping tool; a swipe tool for swiping a surface to gather particles or liquid from a first surface; and a telescope tool, comprising an adjustable length pole.

14. The robotic system of claim 13, wherein the grasping tool is adapted for grasping of a member of a group selected from a vacuum tool attachment and an air sampler cartridge.

15. The robotic system of claim 1, wherein the control circuit assembly includes: a workstation including a microprocessor and a user interface having a display and input means; tracker means for tracking the position and orientation of the trolley assembly, the gantry assembly, the robotic arm and providing a tracker signal indicative thereof; and simulation means responsive to the tracker signal for providing a real-time simulated image on the display of the position and orientation of the trolley assembly, the gantry assembly, the robotic arm, and the end effector in relation to other structure located in the vicinity of the trolley, the gantry assembly and the robotic arm.

16. A nuclear facility comprising a nuclear reactor, a containment around the reactor, and a remotely operated managed maintenance system for performing health physics and maintenance tasks within the containment that includes a robotic assembly within the containment and a control circuit assembly including a workstation located outside the containment for monitoring and controlling operation of the robotic assembly, wherein the robotic assembly includes: an elevated track; a trolley assembly suspended from the track; motorized trolley drive means for moving the trolley along the track; a gantry assembly, including a horizontal gantry and a motorized gantry drive means at a proximate end of the gantry for rotating the gantry about a first vertical axis,* a gantry coupling assembly for attaching a fixed portion of the gantry drive means to the trolley assembly; a robotic arm, including a six motorized joint assemblies coupling between five arm segments for cooperatively moving a distal end of the arm; a robotic arm coupling assembly for attaching a fixed portion of a first joint assembly at a proximate end of the robotic arm to a distal end of the gantry; a plurality of end effectors, each adapted for performing a different one of the tasks in conjunction with the robotic arm; and universal end effector coupling means for removably attaching a selected one of the plurality of end effectors to a distal end of the robotic arm, including air connection means for providing pneumatic air to the end effector, and electric connection means for providing electric power to the end effector and for coupling an electric signal line to the end effector, wherein the control circuit assembly comprises means for remotely controlling each of the trolley drive means, the gantry drive means, each of the joint assemblies of the robotic arm, attachment and detachment of the selected one of the end effectors and operation of the selected one of the end effectors when the selected one of the end effectors is attached to the robotic arm.

17. The nuclear facility of claim 16, wherein the tasks include at least one of: performing a survey of ambient radiation; swiping a surface to gather particles or liquid on the surface; vacuuming a surface; changing an air sampler cartridge in an air sampler cartridge holder; and cleaning particles from a surface with a tacky roller.

18. The nuclear facility of claim 16, wherein the remotely operated managed maintenance system includes video monitoring means for providing video images outside the containment, comprising a video camera at the distal end of the robotic arm for providing a first video image of objects in front of the distal end of the robotic arm, and a pan, zoom and tilt camera mounted on the gantry for providing a second video image of a selected object in the vicinity of the robotic arm.

19. The nuclear facility of claim 16, wherein the track is positioned above a service platform located adjacent a steam generator.

20. The nuclear facility of claim 16, wherein the robotic assembly includes a winch mounted on the distal end of the gantry for lifting objects that are heavier than the lifting capacity of the robotic arm.

21. A method of servicing a nuclear power facility that includes a containment and a steam generator having an adjacent service platform within the containment, comprising the steps of: providing a robotic assembly, including an articulated robotic arm that is capable of movement along a fixed track elevated above the service platform; providing a control circuit assembly for remotely controlling operation of the robotic assembly from a position outside the containment; and performing a task with the robotic assembly under the control of the control circuit assembly.

22. The method of claim 21, wherein the step of performing the task includes the step of attaching an end effector to a free end of the robotic arm.

23. The method of claim 22, wherein the step of performing the task includes the step of repositioning the robotic arm and the attached end effector with the control circuit assembly.

24. The method of claim 21, wherein the task is selected from the group of tasks consisting of: performing a survey of ambient radiation; swiping a surface to gather particles or liquid on the surface; vacuuming a surface,* changing an air sampler cartridge in an air sampler cartridge holder; and cleaning particles from a surface with a tacky roller.step of performing the task.

25. The method of claim 21, wherein the step of performing a task includes the step of providing a real- time simulated image of the robotic assembly and other fixed objects in the vicinity of the service platform.