A kinematic and workspace analysis of a parallel rehabilitation device for head-neck injured patients

Current treatment for patients suffering from cervical spine injuries is by static braces which causes discomfort and immobilization of the neck. This paper presents a novel comfortable wearable therapy device for treating patients suffering with head/neck posture problems using parallel mechanism concept. To achieve this, a conceptual design of a three-degrees-of-freedom Revolute-Prismatic-Spherical configuration parallel manipulator with 3 extensible links is proposed. However, precision and workspace are the general considerations for designing a parallel manipulator. In this research, workspace and position analysis is carried out for the device. By applying geometrical method and vector-loop approach, the inverse kinematics equations are derived. The parallel manipulator is modeled using SolidWorks and simulated using MATLAB. From the simulation results, stroke length of the actuators, angular tilt and position of the moving platform is obtained. To validate the simulation results a preliminary prototype is built and tests were carried. The obtained results found to be satisfying the cause of the research. Furthermore, the device needs to automated and safely operated under the therapist supervision.