Design and control of an active knee rehabilitation orthotic system called ANdROS that was designed as a wearable and portable gait rehabilitation tool is presented. A corrective force field that reinforces a desired gait pattern is applied to the patient's impaired leg around the knee joint via an impedance controlled exoskeleton. The impedance controller is synchronized with the patient's walking phase which is estimated from the kinematic measurements of the healthy leg. The performance of the controller is evaluated through bench-testing.

A newly developed hand rehabilitation system is presented that combines robotics and interactive gaming to facilitate repetitive performance of task specific exercises for patients recovering from neurological motor deficits. A two degree of freedom robotic interface allows coordinated motions of the forearm and the hand (pronation/supination and grasp/release, respectively). It is driven by two novel Electro-Rheological Fluid based hydraulic actuators. Tests were conducted to characterize these actuators, and feed-forward controllers were developed for their force/torque control. A virtual reality environment (maze game) was developed in which the robot applies force fields to the user as the user navigates the environment, forming a haptic interface between the patient and the game.

This paper presents a novel, smart and portable active knee rehabilitation orthotic device (AKROD) designed to train stroke patients to correct knee hyperextension during stance and stiff-legged gait (defined as reduced knee flexion during swing). The knee brace provides variable damping controlled in ways that foster motor recovery in stroke patients. A resistive, variable damper, electro-rheological fluid (ERF) based component is used to facilitate knee flexion during stance by providing resistance to knee buckling. Furthermore, the knee brace is used to assist in knee control during swing, i.e. to allow patients to achieve adequate knee flexion for toe clearance and adequate knee extension in preparation to heel strike. The detailed design of AKROD, the first prototype built, closed loop control results and initial human testing are presented here

This paper describes the development of an adaptive nonlinear PI torque control for electro-rheological fluid (ERF) based variable resistance brakes that are used in compact and portable rehabilitation devices. The electrorheologic fluid (ERF) brake concepts are introduced and previous work performed with a non-linear PI control on ERFs is tested and analysed. The response of ERF brake systems to this non-linear PI torque control, that utilizes an inverse model, is enhanced through the addition of two key components, a step logic function and an adaptable B-spline based algorithm. The description of each is provided along with tests verifying their effectiveness. In addition, the controller's response to disturbances is provided. The effectiveness of the control is validated through testing on two different electro-rheological fluid based brakes

This work aims to demonstrate the feasibility of using Electro-Rheological Fluid (ERF) actuators in orthotics, creating a new breed of rehabilitation devices. ERFs are fluids that experience dramatic changes in rheological properties, such as viscosity or yield stress, in the presence of an electric field. Using the electrically controlled rheological properties of ERFs, compact actuators with an ability to supply high resistive torques in a controllable and tunable fashion, have been developed. This study involves the design, fabrication and testing of an ERF based knee orthotic device and the innovative ERF actuators it uses. The knee orthotic is achieved through a standard brace design with a polycentric hinge and gear system. Coupled to this are two Flat-Plate ERF actuators, given that name for their characteristic set of parallel flat plates allowing for actuation of the fluid. A full model describing the field dependant torque output of these actuators is presented along with a full detailed description of the device design. The overall knee orthotic system is designed to resist up to 25.4% of an average human knee’s torque abilities and be controlled in real-time. The goal of this work is to provide a much more efficient means of rehabilitation over the average orthotic, while matching the proficiency of rehabilitation machines, all in a smaller, simpler, and more cost efficient design.