Biomedical Engineering Reference
In-Depth Information
subject finish the programmed motion (Dipietro
et al
. 2005). Usually the subject
only needs to stay passively and have a sensory experience after the assistive
function is triggered. According to the sensorimotor integration theory, the volun-
tary motor efferent and the afferent sensor experiences together are important and
helpful to promote the reorganization of the brain (Dipietro
et al
. 2005). A more
advanced design in the interactive control requires continuous voluntary motor
inputs from a stroke patient to the robot, and the robotic system gives support, or
even encourages the output from the motor system of the stroke patient but not to
override, during the training. In this chapter, we introduced an interactive robotic
system with continuous voluntary intention control developed in our laboratory
for poststroke rehabilitation training, and its associated training effects by clinical
trial tests.
5.2 REHABILITATION ROBOTIC SYSTEM WITH CONTINUOUS
INTENTION DRIVEN CONTROL
Many signals have been used to indicate voluntary intention in the design for
rehabilitation devices, such as, limb torque, trajectory, electromyography (EMG),
etc. (Hogan
et al
. 1992; Volpe
et al.
2000; Volpe
et al.
2004). In the robotic system
developed in our study, EMG was selected to reflect the voluntary intention of
stroke patients. EMG is the electricity generated in muscles under the control of the
nervous system, and it could be detected non-invasively from the skin surface with
the amplitude in millivolt. EMG signals have been used as indicators of subjects'
voluntary intention in some orthotic and prosthetic devices for paralyzed people
(Rosen
et al
. 1999; Rosen
et al.
2001; Lee and Sankai 2002; Cheng
et al
. 2003), and the
trigger signals in some interactive robotic system for stroke rehabilitation training
(Dipietro
et al
. 2005). In our works, we developed an interactive robotic system
(named PolyJbot) with continuous EMG control (Hu
et al
. 2008; Song
et al
. 2008;
Hu
et al
. 2009) for poststroke rehabilitation training on the elbow, wrist, knee,
and ankle joints with the attempt to encourage the participants to involve more
voluntary efforts during the training (Hu
et al
. 2007; Hu
et al
. 2008; Song
et al
.
2008; Hu
et al
. 2009).
5.2.1 The Robotic System
The rehabilitation robot with continuous intention driven control is shown in
Fig. 5.1(a)
.
It can be applied for interactive training on the upper and lower limbs
with multi-joint configurations. The continuous intention-driven control strategies
applied on different joints, i.e., the elbow, the wrist, the knee, and the ankle
joints are similar, but with respective limb adapters, range of motions (ROMs),
and mechanical setups. In this chapter, the design for the wrist training will be
used for illustrating the implementation of the continuous intention-driven control
algorithm.
