User control modalities to assist people with disabilities to
operate a robotic arm have been previously studied. A physical
joystick is a widely accepted modality for the control of robotic
arms. Joysticks are standard components for most
commercially-available robotic arms, which allow the user to
operate the end effector through directed selection [5]. The
physical joystick is inexpensive, simple in design and can
provide accurate control. However, many robotic arm joysticks
[6] provide two-dimensional control for x and y directional
control and to control z direction by using a twisting control
knob or separate controller. This is sufficient for able-bodied
individuals, but has limited use for people with limited or no
finger or hand mobility, such as those with upper level SCIs
[7]. Another very popular interface for robotic control is
automatic speech recognition system. It is considered as a
solution to the problem of traditional joystick. For example, a system called FRIEND