  The central nervous system exploits anticipatory (APAs) and compensatory
(CPAs) postural adjustments to maintain the balance.The postural adjustments
comprising stability of the center of mass (CoM) and the pressure distribution
of the body influence each other if there is a lack of performance in either of
them.Any predictable or sudden perturbation may pave the way for the divergence
of CoM from equilibrium and inhomogeneous pressure distribution of the
body.Such a situation is often observed in the daily lives of MS patients due
to their poor APAs and CPAs and induces their falls.The way of minimizing the
risk of falls in neurological patients is by utilizing perturbation-based
rehabilitation, as it is efficient in the recovery of the balance disorder. In
light of the findings, we present the design, implementation, and experimental
evaluation of a novel 3 DoF parallel manipulator to treat the balance disorder
of MS.The robotic platform allows angular motion of the ankle based on its
anthropomorphic freedom.Moreover, the end-effector endowed with upper and lower
platforms is designed to evaluate both the pressure distribution of each foot
and the CoM of the body, respectively.Data gathered from the platforms are
utilized to both evaluate the performance of the patients and used in
high-level control of the robotic platform to regulate the difficulty level of
tasks. In the study, kinematic and dynamic analyses of the robot are derived
and validated in the simulation environment.Low-level control of the first
prototype is also successfully implemented via the PID controller.The capacity
of each platform is evaluated with a set of experiments considering the
assessment of pressure distribution and CoM of the foot-like objects on the
end-effector.The experimental results indicate that such a system well-address
the need for balance skill training and assessment through the APAs and CPAs.
