Biomedical Engineering Reference
In-Depth Information
specifications of the robot, and the type of controller used to control the kinematics
and dynamics of the robot. In general, the control achitecture of a rehabilitation
robot consists of two levels of control, a low-level control and a high-level control.
The low-level control schemes are usually implemented using traditional position
or hybrid force controllers. The low-level controller peforms the task of acheiving
the desired kinematic and dynamic behavior demanded from the robot. On the
other hand, the high-level control scheme deals with the robot-user interaction;
this is usually implemented using a rule-base. A detailed review of the different
types of robot therapy modes for rehabiliation robotcs can be found in (Marchal-
Crespo and Reinkensmeyer (2009)).
2.4 ROBOTIC UPPER-EXTREMITY REPETITIVE TRAINER-RUPERT
Robotic upper-extremity repetitive trainer or RUPERT is a wearable exoskeleton
robot developed by Kinetic Muscles Inc. (Tempe, AZ) in collaboration with the
Arizona State University. The main motivation behind the development of this
device was to have a simple, low cost device targeted for clinical and home use.
The very first prototype of the robot was reported in 2005 (He
et al.
(2005)),
and its mechanical structure and technical specifications have gone through an
evolutionary process since the first design (Sugar
et al.
(2005)). The pictures of
of the robot (RUPERT, RUPERT II, and RUPERT III) had four DOFs, shoulder
flexion/extension, elbow flexion extension, forearm supination/pronation, and
wrist flexion/extension. The current version of the robot (RUPERT IV) has an
additional DOF at the shoulder the humeral internal/external rotation; this added
DOF gives the robot a 3D workspace, which is useful for practicing tasks related
to ADL.
The first working prototype of the robot was designed after verifying that the
design of the robot would have the required range of motion in all the DOFs,
and the pneumatic muscle actuators used for actuating the different DOFs could
acheive the required range of motions for assisting ADL related tasks such as
reaching, washing and self-feeding. The second version of the robot resulted from
the modification of the previous design to accomodate for subjects of varying
body types and shapes. In this version, the center of rotation of each joint and
the length of each segment of the robot were made adjustable, which resulted
in increasing the device complexity, number of components on the robot, and
also its final weight. Version III was developed
(
Fig. 2.1(c)
)
based on the fitting
evaluations from a range of statures of able-bodied and stroke subjects, and device
testing of Version I
(
Fig. 2.1(a)
)
and II
(
Fig. 2.1(b)
)
at Banner good Samaritan
Regional Medical Center. The robotic components of RUPERT III were built from
a composite material that helped reduce the overall weight of the robot. All these
three versions of the robot had four DOFs with two DOF controlling reaching and
other two controlling the orientation of the hand. This meant that the reaching
workspace of these robots was a 2D surface. Although this is suitable for training
