Biomedical Engineering Reference
In-Depth Information
Figure 2.4
Plot of the joint angle profiles of the shoulder flexion/extension, elbow flex-
ion/extension and humeral rotation DOFs for the three therapy modes developed for
RUPERT. For color reference, see page 210.
these modes; the point-of-assistance is delayed in the active-assist therapy mode
compared to other two modes, where the robotic assistance is present from the
start of the therapy task. It is also evident from these plots that when there is
voluntary contribution from the subject, the resulting movement's smoothness is
reduced (compare row 1 with rows 2 and 3).
2.6 A VIRTUAL REALITY-BASED BIOFEEDBACK INTERFACE
A virtual reality-based biofeedback software interface was developed in our lab
using the Panda graphics engine. The software also has the capability to allow a
physician/therapist to use the RUPERT system to design and administer robot-
assisted therapy. This software is run by the host PC. The screen-shots of the
interface consists of a virtual model of the human arm that is driven by the joint
sensors in RUPERT. The data recorded from these sensors are streamed by the
single board computer to the host PC through an UDP interface. In addition to
the visual stimuli provided through the virtual environment, the program also
provides suitable audio cues about the therapy task to the subject. Since the virtual
environment is driven by the joint angles sensed using robot that is worn by the
stroke subject, the effect of trunk movement is completely eliminated; pure trunk
movements without any movement of the arm relative to the trunk will not change
