Realization of virtual fluid environment on a robotic gait trainer for therapeutic purposes


Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Mechanical Engineering, Turkey

Approval Date: 2017

Student: TAYFUN EFE ERTOP

Co-Supervisor: AHMET BUĞRA KOKU, ERHAN İLHAN KONUKSEVEN

Abstract:

Patients with disorders such as spinal cord injury, cerebral palsy and stroke can perform full gait when assisted, which progressively helps them regain the ability to walk. A very common way to create assistive effects is aquatic therapy. Aquatic environment also creates resistive effects desired for increasing muscle activity. Simulating the fluid environment using a robotic system would enable therapists to adjust various fluid parameters so that the therapy is tailored to each patient’s unique state. In this study, realization of a virtual fluid environment on a robotic gait trainer for rehabilitation purposes is presented. A model is created to determine torques and forces exerted on a partially submerged human body by the fluid environment. Then, the fluid model is used to create a control scheme which is implemented on a robotic gait trainer. A compensation algorithm is developed so that weight and friction of robotic links are countered. Smooth transition between stance and swing phases of gait is ensured with a developed algorithm that only uses kinematic data. Experiments with healthy subjects were done to verify the stance-swing algorithm, the changes in gait characteristics between land and water conditions, and to assess effects of changes in fluid model parameters to gait characteristics. It is shown that realization of virtual fluid environment on robotic gait trainer is achieved. The torque measurements showed that the controller was able to make the orthosis transparent to the patient. Significant changes in gait characteristic were observed by modifying fluid model parameters.