Presentation Title

Characterization of Sensors employed in an automated Knee Brace for Leg Muscle Rehabilitation

Presenter Information

Harsh PatelFollow

Faculty Mentor

Sohail Zaidi, Vimal Viswanathan

Start Date

23-11-2019 8:00 AM

End Date

23-11-2019 8:45 AM

Location

155

Session

poster 1

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

In a current project at San Jose State University, an automated orthotic knee joint is being developed that may assist rehabilitation of partially paralyzed patients. This device uses electromyography sensors to gather impulse signals and use pneumatic actuators in the form of fluidic muscles. A microcontroller is used to interpret the signals from the sensors and uses a feedback control loop to provide augmented strength and mobility to the wearer. Various types of sensors are used to monitor the brace operation that includes rotary encoders, force, and electromyography sensors. For an accurate functioning of the knee brace, it is essential to characterize these sensors before these are embedded in the system. The work presented here describes the methods that were used to characterize and calibrate force sensors and rotary encoders selected for this project. The Keyes KY-040 rotary encoder used here is a rotary input device that indicates how much the knob has been rotated along with is the direction of rotation. To calibrate this sensor, an Arduino was used in conjunction with an experimental setup where the rotation of the encoder was simultaneously recorded with a protector attached to the encoder. A 3D printer was used to develop the encoder holder that was embedded inside the knee. To measure the applied force as the knee brace is moved in the upward direction, a 0.5-inch FSR402 (thin-film pressure sensor) was selected. Before implementing the sensor inside the system, it was calibrated, and for this purpose, a calibration stand was designed and constructed. The work presented here will describe in detail the methodologies adopted for calibration of two sensors and will present the calibration curves for both sensors. The discussion will also include preliminary experimental results for the knee-brace movement (angle) mounted on a mannequin leg as a function of fluidic pressure.

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Nov 23rd, 8:00 AM Nov 23rd, 8:45 AM

Characterization of Sensors employed in an automated Knee Brace for Leg Muscle Rehabilitation

155

In a current project at San Jose State University, an automated orthotic knee joint is being developed that may assist rehabilitation of partially paralyzed patients. This device uses electromyography sensors to gather impulse signals and use pneumatic actuators in the form of fluidic muscles. A microcontroller is used to interpret the signals from the sensors and uses a feedback control loop to provide augmented strength and mobility to the wearer. Various types of sensors are used to monitor the brace operation that includes rotary encoders, force, and electromyography sensors. For an accurate functioning of the knee brace, it is essential to characterize these sensors before these are embedded in the system. The work presented here describes the methods that were used to characterize and calibrate force sensors and rotary encoders selected for this project. The Keyes KY-040 rotary encoder used here is a rotary input device that indicates how much the knob has been rotated along with is the direction of rotation. To calibrate this sensor, an Arduino was used in conjunction with an experimental setup where the rotation of the encoder was simultaneously recorded with a protector attached to the encoder. A 3D printer was used to develop the encoder holder that was embedded inside the knee. To measure the applied force as the knee brace is moved in the upward direction, a 0.5-inch FSR402 (thin-film pressure sensor) was selected. Before implementing the sensor inside the system, it was calibrated, and for this purpose, a calibration stand was designed and constructed. The work presented here will describe in detail the methodologies adopted for calibration of two sensors and will present the calibration curves for both sensors. The discussion will also include preliminary experimental results for the knee-brace movement (angle) mounted on a mannequin leg as a function of fluidic pressure.