The robotics manipulator used for our research is a commercial robotics manipulator from Rhino Robots Inc. It is a XR-4 arm driven by a Mark IV controller. The XR-4 are 5 axis revolute corrdinate robot arms with a motor driven gripper. It can be extended up to 22.5 inches and lift weight up to 4.0 lbs.
All its axes are controlled by DC servo motors using incremental optical encoders for feedback and contain limit switches which are used to position the arm to a hardware (known) home position
(extracted from RHINO: The XR-3, XR-4 and SCARA MANUAL).
WYL