Session: 05-12-02: Robotics, Rehabilitation - II

Paper Number: 95818

95818 - The Design Evolution of a Lower Extremity Exoskeleton Device for Leg Muscle Rehabilitation 

As an ongoing activity at San Jose State University, the design of wearable exoskeleton devices has evolved over the last few years. These devices provide much-needed robotics-assisted rehabilitation for the elderly population requiring physical therapy to recover from leg injuries. The target is to create an exoskeletal device for rehabilitation that can replace the cost of expensive physical therapy treatments. The assistive knee brace consists of pneumatic muscles that closely recreate human muscle rehabilitation in the current design. The knee brace is activated using surface electromyographic (EMG) sensors to start motion. The very first design consisted of two fluidic muscles developed by Festo Corp., which were later replaced by custom-built soft actuators. These muscles are actuators powered by a pneumatic system that expands or contracts depending on the compressed air entering the system. An Arduino-based controller performs the pneumatic control. The first design was mounted on a human leg where several EMG sensors were placed on the upper part of the leg randomly to activate the controllers. The brace was designed to take the leg through a 70-180 degrees range and was tested for a 30-minutes continuous operation. This device is currently further modified for patients who have undergone total kneed replacement surgery and need leg rehabilitation exercises to recover. In this design, multiple fluidic muscles are incorporated that are controlled by Arduino based system to activate and deactivate the fluidic muscles. Multiple fluidic muscles were used to minimize the reaction time of the device. The brace is designed to mount it on a knee of a sitting person and consists of four bars (two bars are mounted on the thighs and the remaining two on calves). EMG sensors are placed on six muscles, including Vastus Medialis, Vastus Lateralis, Rectus Femoris, Semitendinosus, Biceps Femoris, and Semi-membronasus. The new knee brace is fully characterized by mounting it on various sitting person’s legs. The leg motion is being investigated as a function of air pressure inside the fluid muscles and the location of EMG sensors on the legs for various age groups. This paper will include the systematic design improvement in our knee-brace device and its applications. The software that processed the EMG sensors was modified to reject the input noise to give an accurate and fast response. The details of the software and its processing will be discussed in greater detail. The device characterization results will be summarized for practical applications.

Presenting Author: Vimal Viswanathan San Jose State University

Presenting Author Biography: Dr. Vimal Viswanathan is an associate professor in the mechanical engineering department at San Jose State University. He is also serving as the department chair at the moment.

Authors:

Patrick Fusilero San Jose State University
Andres Reyes San Jose State University
Rodrigo Trejo San Jose State University
Indeever Madireddy Intelliscience Institute
Aayush Vemuri Intelliscience Institute
Soahil Zaidi Intelliscience Institute
Vimal Viswanathan San Jose State University