Abstract:
Monitoring of muscle activities of human limbs is
essential for designing controllers of wearable robotic devices
such as prosthetics, orthotics and exoskeletons. Human-robot
interaction (HRI) is generally studied to control these devices
and ascertain comfort levels of the wearer. Cognitive-HRI (cHRI)
and physical-HRI (pHRI) are the two main types of HRI methods
identified in literature. Surface electromyography (sEMG) signals
of skeletal muscles are commonly used in cHRI methods to
identify the motion intentions. However, sEMG signals are
sensitive to the environmental conditions such as electric and
magnetic disturbances. Alternatively, changes to muscle stiffness
and volume are measured in pHRI methods. Accordingly, this
paper presents a novel sensory system to detect motions of upper
or lower limbs by monitoring surface-muscle pressure (SMP). It
is comprised of specially designed ’pressurized-air-pouches’ made
of silicone. Experiments were carried out with the developed SMP
monitoring system to detect muscles activities during biceps curls.
The results were compared against sEMG signals to evaluate
the validity of the proposed method. The analysis indicated a
strong correlation between the signals measured and verifies the
potential of using SMP as an effective muscle activity sensing
method.
