This doctoral thesis is dealing with robotic exercise for support in motor rehabilitation
of patients with movement disorders of the upper extremities.
The first part of the thesis is focused on an unobtrusive measurement of the persons’
physiological response. First, different physiological processes, that manifest themselves
as bioelectric and other types of signals, are described. State of the art technologies
for measuring these signals are presented, based on the literature review a new measurement
system is proposed. Unobtrusive measurement methods are described for
different physiological signals, followed by proposed signal analysis and processing. The
proposed system was experimentally validated.
Validation was performed by using a reference measurement system, considered as
the gold standard for physiological measurement. Raw signal correlation was performed
for all physiological signals, as well as parameter comparison. A thorough analysis
of motion artifacts and signal quality during tasks was conducted. An adaptive task
controller for a physical robot interaction task si validated in the last part of the chapter.
Controller was based on a tree structure, using physiological and biomechanical signals
from the proposed system as inputs.
Second part of the thesis is concerned with analysis of a variable stiffness actuator
and methodology for control. Variable stiffness actuators enable a safe human-robot interaction.
The chapter starts with a review of different variable stiffness configurations.
It is followed by a detailed description of a antagonistic variable stiffness configuration,
utilizing non-linear springs for stiffness adjustment. Detailed description of LinWWCVSA
actuator is presented, along with the stiffness and force models. These can be
implemented in actuator control.
Further, a new version of a haptic interface is presented, using the LinWWC-VSA
configuration. Hardware and software used by the interface are described in detail, followed by kinematic and dynamic modeling of the interface. Different performance
measures for haptic interfaces are described, followed by an experimental review of
the haptic interface. Position and force control methods are proposed and analyzed.
Force calibration and measurement is presented together with control. Finally, active
compliance control is presented and analyzed. Impedance and admittance control
strategies are evaluated.