Design and Modeling of a Parallel Continuum Manipulator for Trunk Motion Rehabilitation

Abstract

Abstract The objective of the present work is to develop a device for training the trunk balance and motion during the early stage of rehabilitation of patients who have suffered a stroke. It is coupled to a standing frame and is based on a parallel continuum manipulator where a wearable jacket is moved by four flexible limbs actuated by rotary motors, achieving the translation and rotation required in the trunk to perform a given exercise. The flexible limbs act as a natural mechanical filter in such a way that a smooth physiological motion is achieved, and it feels less intimidating to the patient. After measuring the kinematic requirements, a model has been developed to design the system. A prototype has been built and a preliminary experimental validation has been done where the jacket generates translation coupled to a rotation around the anteroposterior, medio-lateral and longitudinal axis. The measurements of the motors torque and the force sensors located in the flexible limbs have been compared with the simulations from the model. The results prove that the prototype can accomplish the motions required for the rehabilitation task, although further work is still required to control the interaction with the patient and improve the performance of the device.