Design and Analysis of a Hybrid Position/Force Controller for Robotic Rehabilitation of Upper Limb after Stroke

Abstract

There is an increasing number of stroke victims, leading to an increasing number of motor deficits as a result of stroke. Rehabilitation is an important factor in trying to improve the life quality of stroke victims. General physical therapy is a common approach, but the field of robotic rehabilitation is an expanding field of study.

The motivation for this thesis is to design a rehabilitation robot to enhance the rehabilitation offered to patients suffering from motor deficits after stroke.

The main objectives are to first present a literature review on the matter of end-effector based rehabilitation robots followed by a suggestion to an approach believed to be suitable. There are several robotic rehabilitation systems available. This thesis chooses and implements a control strategy based on the literature and suggest a functional design for verification of the control strategy.

The result of this work is a proposal and analysis of a hybrid position/force controller for robotic rehabilitation of an upper limb after stroke. The controller has been verified by simulations on a 2 degree-of-freedom robot manipulator. Two approaches to force control were tested, and a conclusion to which approach is best suited for this particular purpose is presented.

The thesis also discusses how to design a model and a controller for a robot manipulator. The model in this thesis is based on a 6 degree-of-freedom UR5 robot manipulator as well as a simple 2 degree-of-freedom planar robot manipulator.