Manipulator selection is based primarily on the intended application. For laboratory type operations a light-duty highly dexterous manipulator is desired. For process applications or maintenance of process equipment a standard or heavy-duty type manipulator should be used.
There are two types of mechanical manipulators:
The single unit manipulator is the most widely used and is less expensive than the three piece manipulator. The single unit manipulator, as the name implies, consists of a master arm, slave arm, and through-the-wall tube assembled as one unit. The tendons which transmit motions from the master to the slave are continuous closed loops. The single unit manipulator is installed in the hot cell from the operator's side. This is accomplished by indexing the slave arm to a position in line with the wall tube, inserting the manipulator into the wall sleeve, then indexing the slave arm down to an operating position inside the hot cell. The single unit manipulator is typically used when the in-cell atmosphere is air instead of inert gas. A booting assembly is used to restrict air flow into the hot cell and to protect the slave arm from contamination.
The three piece manipulator is typically used in an inert atmosphere cell, i.e., where the in-cell atmosphere is carefully controlled. The three piece manipulator consists of three independent assemblies, the master arm, the slave arm and the through the wall tube (seal tube). The master arm is removable and interchangeable with any seal tube. The slave arm is remotely removable with an in-cell crane and is also interchangeable with any seal tube. The seal tube is maintenance free and usually remains in the wall. When using a three piece manipulator, provisions should be made to remove the slave arm from the hot cell through an air lock or transfer port for maintenance. The three piece manipulator may also be installed and removed from the operator side similar to the single unit manipulator but this option defeats the purpose of the three piece flexibility.
Once you have determined whether a single unit or three piece manipulator is required, the operating characteristics are the next level of definition. Handling capacity, friction and deflection are important measures as to how the manipulator will feel to the operator. Low friction and small deflections will result in a very responsive system that becomes transparent to the operator and allows the operator to concentrate on the task at hand rather than specific manipulator movements. Since mechanical telemanipulators have a one-to-one ratio between master and slave, the handling capacity is limited to 50 pounds (22 kg), the maximum weight an operator would be expected to handle. CRL does offer a 100 pound (45 kg) capacity manipulator (Model F) for very rugged duty applications where heavy pushing may be required. However, the Model F is only available in the single unit configuration.
The final criteria for defining the manipulator is the selection of the accessories. CRL offers a wide range of accessories including a choice of tongs and adapters, air-flow restriction, booting, laminated or labyrinth radiation shielding, motion locks, electrical indexing of X, Y, and Z motions, tamper locks, load alarms, etc. The selection of accessories also depends on the application and operating environment of the manipulator system.