Central Research Laboratories (CRL) was founded in 1945 and planned as a technically orientated, high quality, small lot, precision manufacturing and engineering company. This criteria has proved to be very descriptive of CRL over the course of time. After over 50 years of operation CRL has emerged as the world leader in the design, development and production of Master-Slave Manipulators (MSM). CRL has manufactured and delivered over 8000 MSM's with installations in over 25 different countries. This represents about 70% of the free world market.
The first MSM, the Model 1, was publicly demonstrated by its inventor, Ray Goertz, at the Argonne National Laboratory of the U.S. Atomic Energy Commission in 1949. The terminology comes from earlier usage in mechanical and electrical terminology in which a device which is responsive to another device is termed a "slave" and the controlling device is termed a "master". The Model 1 defined the essential characteristics a remote handling device must have to be termed a "Master-Slave Manipulator." The basic features which characterize an MSM are:
The first manipulators developed under the direction of Ray Goertz at Argonne were designed to be installed with the slave arm penetrating the ceiling of a shielded cell. Space above the cell was required to accommodate installation and manipulator motions. Shielding of the slave arm penetration through the ceiling was difficult. Models of this type which found considerable use were the Model 4 and Model 7.
When the need was recognized for better shielding than could be provided by the Model 4 or 7, the Model 6B was developed at Argonne. The Model 6B was the first manipulator design to penetrate only the vertical shielding wall of the cell. In one version of the 6B, a horizontal slot had to be provided in the vertical wall so the manipulator could be rotated 90° from its normal position and installed. In another version, the slave end was disconnected from the master end and reconnected after the thru tube was installed into a hole in the vertical wall just large enough to accept the thru tube. This version required that the cell be entered for installation, removal, or any maintenance required on the slave arm.
Central Research Laboratories' participation in the Master-Slave Manipulator market began in 1950. CRL, through previous associations with Ray Goertz and Argonne, obtained drawings of the Model 1 MSM and manufactured two sets of manipulators in 1950 for experimentation and testing by CRL. These two manipulators were sold to the Aberdeen Proving Grounds in 1951 and became CRL's first sale of MSM's.
During the time period from 1951 through 1954, CRL manufactured and delivered 74 sets of MSM's. These manipulators were Model 4, 6B and 7 types. Some of the notable customers were:
By 1953 it became apparent that there was a need for a manipulator that would penetrate only the vertical face of the cell and could be easily installed and removed from the operators side of the shielding wall without the necessity of entering the cell. It was also becoming necessary to have the the ability to handle heavier loads than the 5 kg capacity of the Model 4, 7 and 6B. To achieve these goals, Argonne National Laboratory gave CRL a contract to design, develop and produce such a manipulator. The result was the Model 8 manipulator with Demetrius Jelatis of Central Research Laboratories as the chief inventor. Because the Model 8 was developed under government contract, the design became public domain and versions of the the Model 8 manipulator were manufactured by CRL and other companies in the United States and other countries. The Model 8 quickly became the manipulator of choice as the hot cells became larger and more demanding tasks were being performed. It is our estimation that CRL has manufactured 60-70% of the existing Model 8 and related type manipulators used.
Some of the more important and revolutionary new features designed into the Model 8 manipulator and related manipulator designs which followed the Model 8 are:
After the development of the Model 8 Manipulator, CRL established a alphabetical designation for its models to distinguish them from the numerical series which originated from the Argonne National Laboratory. Models directly related to the Model 8 manipulator which were developed at CRL in subsequent years were the Model D (1960), the Model E (1961), and the Model F (1962).
The earlier MSMs were visualized as tools for performing light laboratory operations and the emphasis in design was to produce a light, low friction, low inertia device. Very soon it became apparent that the industry required a manipulator with much higher load capacities. The rugged duty Model D (1960) manipulator was designed to meet this need. The design goal of the Model D manipulator was to produce a device that could withstand all the force a human operator could exert while standing in a normal operating position. This was achieved with a modest sacrifice in inertia and friction characteristics. The basic characteristics were achieved by careful proportioning of parts and the selection of materials. The azimuth rotation motion incorporated step-up and step-down gearing to reduce the tape loads and deflection. The handle-tong drive incorporated pulley multipliers at the tong and handle ends to reduce the tape loads and deflections. The handle design for the Model D incorporated a force-multiplying system so gripping forces of 45 kg could easily be developed. The handle design also featured a ball rigidly positioned forward of the wrist joint at about the point a load would be positioned in the tong jaws. This permitted the operator to exert a lifting force over the approximate center of gravity of the load with one hand while the other hand is used on the handle to manipulate the load.
As hot cells increased in size the need for manipulation throughout larger volumes lead to the development of the extended-reach manipulator designated as the Model E in 1961 by CRL. The design criteria for the Model E was to produce a manipulator with a increased volume of coverage and the same characteristics as the Model 8. In the extended reach manipulator an intermediate extension tube was introduced in the telescoping system of the slave arm. The extension feature is motor driven Z motion indexing and allows full use of the manual Z motion over the full range of the indexing.
In 1962 an extended reach version of the Model D manipulator was introduced and designated as the Model F by CRL. It is interesting to note that, because the rugged-duty manipulators generally find their way into large hot cells, the customers' demand for the Model F has completely replaced the Model D which, as a result, is no longer manufactured by CRL.
In 1970 some of CRL's customers who had been using Model 8 and E type manipulators requested that we produce a manipulator with the same coverage as the Model 8 and E with a load capacity of about 20 kg for installation into their existing cells. The tasks to be performed in their cells had changed and they required manipulators with higher load capacities. This led CRL to develop this load class of manipulators designated as the Model 8-HD and Model E-HD. To achieve the design requirements, a new wrist joint was designed with a higher gear ratio to reduce the tape loads and deflections for the wrist motions. The azimuth motion incorporated a pulley multiplier at the master and slave ends to reduce cable loads and deflections. Careful sizing of parts and selection of materials allowed the capacity of the manipulator to be increased to the desired capacity. The Model 8-HD and E-HD have now become a important part of CRL's manipulator line and allow our customers a wide selection of load capacity to meet their requirements.
While the evolution of the Model 8 family of manipulators had been evolving in the direction of heavy-duty and large volume coverage models, there was still a need for a smaller, light-duty, more compact manipulator. In 1964 the Model G manipulator was designed and developed at CRL to satisfied this need. The design requirement for the Model G was a light-duty, low-friction, low-inertia manipulator that could be mounted through the shielding wall. The manipulator was designed with Z and elevation/twist motions tape driven to achieve low friction. The manipulator was designed to mount in a 190 mm diameter hole through the shielding wall. The manipulator also had to have a minimum collapsed length so the height of the cells could be made as low as possible. This was to reduce the unused portion of the cell to a minimum. To achieve a compact and minimum collapsed length of the slave arm, CRL came up with the concept of a double telescoping slave arm. This concept allowed the manipulator to mount at lower heights while retaining good cell coverage. The manipulator was also designed with electrical X and Y motion indexing and the option of variable Z motion (ranging from 1:1 to 2:1) between the master and slave arms.
In 1980 the requirement developed for a compact Model G type manipulator with higher load capacity, more reliability, and the same geometry so it could be retrofitted into existing cells. The situation was similar to the changing requirements of the Model 8 family of manipulators. The tasks performed in the cells were becoming more demanding and customers wanted to retain the compact cell design they had become accustomed to. To satisfy this requirement CRL designed and developed the Model G-HD, retaining the same geometry of the Model G so the Model G-HD could be retrofitted into existing facilities. The design objectives were achieved by converting the arm to a cable-driven manipulator and increasing the strength and rigidity of the wrist joints. These changes did result in increased friction compared to the model G but it greatly increased the reliability and was totally satisfactory to our customers. The Model G-HD has become a very popular and dependable manipulator.
In 1990, an extended reach version of the Model G-HD was developed. This manipulator, designated the Model G-HDE, featured electrically-driven Z motion indexing to reposition the slave tong relative to the master handle. This allows the operator to maintain a comfortable position over the entire range of manipulator Z motion. The same advantages could be achieved using a variable-ratio Model G-HD, but the G-HDE maintains the 1:1 ratio of master-to-slave motions and forces, whereas the variable-ratio Model G-HD does not. Unlike models with conventional extension motions (e.g. Model E, Model F, etc.), however, the use of Z motion indexing reduces the amount of manual Z motion available.
By 1992 there was a requirement for a very compact manipulator that could be utilized in small gloveboxes. CRL developed a version of the Model G (designated the Model G-LD) to meet this need. The Model G-LD does not have electrically-indexed motions. Instead, it features a manual Y indexing capability. The result is a compact, lightweight and inexpensive manipulator that works well within the confines of a small enclosure.
In 1960 CRL realized that there was a requirement for a completely sealed manipulator to allow for total isolation of the cell atmosphere from the outside atmosphere. All the manipulators which had been previously developed depended on schemes for booting the manipulator to control the gas flow into and out of the cell. With the introduction of inert gas cells and the task of handling items which produced toxic gases or airborne contamination, it became apparent that a sealed gas tight manipulator was required. CRL's answer to this requirement was the design and development of the Model A Gas Tight Manipulator. The Model A manipulator consists of three distinct and easily separable assemblies: the master arm, the seal tube, and the slave arm. The seal tube and master arm assemblies can be easily installed from the operator's side of the cell. The slave arm can be installed remotely with the use of a bridge crane or other handling device in the cell. The master arm and slave arm can be removed or installed on the seal tube without breaking the integrity of the cell. In the Model A manipulator all motions were transformed into rotary motions at the interface between the cell and the external atmosphere. The motions are transferred across the boundary with sealed rotary packages. Each seal package has two rotary face seals and the space between the seals can be pressurized with the same gas that is used in the cell from the operator's side to a pressure slightly above the cell pressure so it is virtually impossible for leakage across this boundary. Monitoring of the pressurizing gas allows the detection of a leak and any leak that occurs will be a leak of the pressurizing gas into the cell or the outside atmosphere. Seals of this type have been in use for over 30 years without failure.
In 1966 one of our customers had a requirement for a gas-tight manipulator with motor-driven Z motion extension. The Model J manipulator, an extended-reach version of the Model A, was produced. The Model J manipulator has the same load capacity and operating characteristics as the Model A and has replaced the Model A which is no longer manufactured by CRL.
In 1968 the requirement developed for a sealed G type manipulator. Some of the customers who were using G type manipulators in compact cells were now moving toward inert gas cells and total containment. Their requirement was for a small compact light-duty, three-piece, gas-tight manipulator that could be installed through the vertical face of the cell and/or have the capability of removal and installation of the slave arm remotely. CRL's designation for this manipulator was the compact gas-tight Model L. The Model L retained the Model G geometry for the master and slave arm and the motions were converted to rotary motions at the master and slave wall interface. The seal tube assembly consists of six shafts with double oil lip seals at the master and slave interface. The seventh sealed motion is the rotation of the thru tube within the seal tube assembly. The seal tube was designed so the space between the sets of seals could be pressurized with the type of gas being used in the cell. The Model L manipulator was designed to install in a 190 mm diameter wall tube so it could be retrofitted into the cells which previously had Model G type manipulators. Unlike the Model A and J sealed manipulators, the Model L was designed so the slave arm could be indexed to a horizontal position so it could be installed into the vertical shielding wall from the operator's side. The Model L was also designed as a three-piece manipulator so the slave arm could be installed or removed remotely by a in-cell overhead crane or handling device. It is interesting to note that the first application for the Model L was non-nuclear. The first six Model L manipulators produced by CRL were installed into two large high vacuum chambers by Martin Marietta of Denver and used to evaluate materials for NASA's Mars Viking Lander. These vacuum chambers were operated at 10e-7 Torr.
With the growth of the industry in the United States and other countries there was increasing demand for heavy-duty handling capacity, ease of maintenance, and increased reliability, particularity in sealed manipulators. The designation System 50 was selected by CRL for such a manipulator to indicate a manipulator that could be used to routinely handle loads up to 23 kg. It was termed a system because one of the goals was to achieve a design that would lend itself to modification to meet a variety of needs. The design activity began in 1973 and the first production lot of manipulators was started in 1978. The System 50 is separable into three units and the slave arm can be indexed to a horizontal position so it can be installed from the operator's side of the cell or remotely from inside the cell. Unique features of the System 50 include:
The System 50 manipulator probably represents the most advanced manipulator design in mechanical manipulators to date. The System 50 manipulator was designed with technical superiority only in mind so it is generally finding its applications only in situations where its relatively high cost can be justified.
In about 1980 in response to the Japanese market, CRL began the design and development phase for the Model R and Model RE (extended reach) type of sealed manipulator. The first production models of this type were produced and delivered in early 1983. This family of sealed manipulators is separable into three units, indexable so the slave arm can be installed or removed from either inside or outside the cell, and has a handling capacity of 23 kg. To achieve high reliability the slave arm was designed as a cable manipulator with chain drive in the wrist joints for both wrist motions and tong motion with a minimal sacrifice in friction and deflection characteristics. The handle and tong were designed to meet the requirements of our Japanese customers. The seal tube design is similar to the Model L type of seal tube and uses oil lip seals for the seal elements. When compared to the System 50 manipulator, the Model R family of manipulators is a considerably less expensive manipulator yet has good reliability. In 1990 a third manipulator was added to this family and was designated the Model RE-FB. This manipulator is a full-balance version of the Model RE and has the same characteristics. It is interesting to note that, since the development of the handle and tong for the Model R family of manipulators, this handle and tong has been supplied on many of CRL's other manipulators for the Japanese market and the wrist joints have been used on the Model E-HD manipulators.
In 1990 the Model L-HD manipulator was added to the CRL manipulator product line to satisfy customer demand for a heavy-duty compact sealed manipulator. The Model L-HD is a heavy-duty version of the Model L sealed manipulator and retains the same geometry and characteristics.
The Model L-HDE was developed in 1993 to include electrically-driven Z motion indexing of a variety similar to the Model G-HDE. This indexing gives the operator greater cell coverage while maintaining a comfortable handle position.
All of the manipulators mentioned to this point are basically mechanical master-slave manipulators. CRL has also had a long involvement in the servo-manipulator field. As early as 1953, Ray Goertz of Argonne National Laboratory had started the development of a true bilateral force-reflecting servo-manipulator in which the only coupling between the master and slave arms was electrical. By 1966 the Argonne group had developed four successive models of the servo-manipulator. The last model was the Mark E4A.
In 1971 CRL made some minor modifications to the Mark E4A structure and designated this manipulator the Model M. The Model M was a 18 kg capacity, articulated, analog-controlled system with force ratios of 1/1 to 5/1. In 1971 CRL manufactured three sets of the Model M servo manipulator and delivered two sets to the Fermi National Accelerator Laboratory. The remaining manipulator was retained at CRL for experimentation and development of a more sophisticated electrical control system. The control system was called the Triac control and was retrofitted on the Model M manipulators at Fermi in 1974. The Model M manipulator performed extremely well and has proven to be a reliable manipulator. The existing pair of manipulators is still in use at the Fermi Accelerator Laboratory.
In 1981 CRL entered into a fixed price contract with the Oak Ridge National Laboratory to provide a pair of state-of-the-art servo manipulators for a fuel reprocessing demonstration project. The state-of-the-art servo manipulator at the time was the Model M. It was CRL's position that, because of all the advancements which had occurred in electronic control and the demanding requirements of reprocessing, the manipulators ultimately supplied should exceed the performance of the Model M. This new servo-manipulator was designated the Model M-2. The Model M-2 retained the same articulated geometry of the Model M and selective components and manipulator structure was upgraded to provide a peak handling capacity of 45 kg. In collaboration with Oak Ridge, a digital control system and software was developed for the Model M-2. The Model M-2 became the first digitally-controlled bilateral force-reflecting servo-manipulator. The force ratios provided were 1/1, 2/1, 4/1 and 8/1. The performance of the manipulator was excellent. CRL also provided the interface package for mounting the manipulator to a overhead telescoping bridge crane for transporting the manipulator work station around the large work cell area. The interface package included television cameras, lighting, manipulator mounting, 225 kg hoist, rotary azimuth drive for positioning the interface package on the end of the telescoping tube and connection to the telescoping tube of the bridge crane. The manipulator system was delivered to the Oak Ridge National Laboratory in early 1983. The system performance and reliability was excellent and the system is still in operation.
In 1985 CRL began the design and development of the SAMSIN servo-manipulator system. The SAMSIN manipulator used the telescoping tube geometry of CRL's mechanical master-slave manipulators and the master and slave arms are very similar to the Model L. The digital control technology from the Model M-2 was transferred to the SAMSIN and commercially available electronics and motors were used. The slave arm is designed to be remotely removable from the motor package and the motor package is designed to be remotely removable from the manipulator mounting package so each unit can be transferred to a contact maintenance area if required. The manipulator has a 12 kg handling capacity. This equipment was first demonstrated at the NASA Goddard Space Flight Center where CRL, with the use of SAMSIN, completed a ground-based demonstration of the Solar Max Electronic Panel replacement procedure the astronauts completed on the Solar Max Satellite in 1984.
Servo manipulators have seen limited use in the nuclear market. Their high cost compared to a mechanical manipulator and limited exposure in a high radiation environment have greatly restricted their application. CRL firmly believes that servo-manipulator systems must be custom designed for the customers application and that all design considerations be mutually discussed and agreed upon by both parties.