Novel EMG-IMU Sensor Array for a 5-DOF Wearable Robotic Upper-Limb Exoskeleton; Autonomous Vehicles: Application of the Seat Belt Analogy for Traffic Safety

Grbic, Meliha, School of Engineering and Applied Science, University of Virginia
Sun, Sarah, EN-Mech/Aero Engr Dept, University of Virginia
Elliott, Travis, EN-Engineering and Society, University of Virginia

Sociotechnical Synthesis
As technology becomes autonomous, it gains more power over the decisions that are delegated to human beings. Due to the fact that autonomous technology is faster at reacting, it is often considered safer and more effective than relying on human capabilities. The motivation behind this thesis was to explore the ways in which autonomous technology is developed and the ethical implications behind its mandatory usage due to safety concerns. The technical project involved the development of a wearable upper-limb exoskeleton which would be used to help patients with muscular weakness perform daily tasks. Eventually, the exoskeleton would become autonomous in the sense that it would compensate and determine the amount of actuation/force needed only via the use of sensors. The STS research project explored the validity of a regulatory mandate of Level 4 autonomous vehicles in the United States.
Technical Project
The technical project was divided into two parts: actuator (muscle) design and sensor design. The goal of the sensor design team was to create a wearable upper-limb exoskeleton for five degrees of freedom. Eight electromyography (EMG) sensors were used to detect muscle activity and three inertial measurement unit (IMU) sensors were used to give angle feedback. The sensor array, comprising both EMG and IMU sensors, is designed to provide information regarding the patient's intended muscle action to the actuator system and to generate feedback for the actuators. The patient's intended motion is to be interpreted by eight EMG sensors that directly measure the electrical impulses of the local nervous system. Experiments involved connecting the EMG and IMU sensor array to a microcontroller to read the data. Then, a human test subject (a 22-year-old female) was fitted with the sensor array. The placements of the IMU sensors were consistent across every test. Each EMG sensor is attached to two gel electrodes, one of which is placed on the belly of the muscle and the other is placed at another point such that the sensor is parallel to the muscle fibers. During testing, in all three experiments, the subject was instructed to perform certain motions while being video recorded. At the same time, the data from the sensors was being read out to the Arduino serial terminal. Aligning the video to the Arduino’s clock allowed the experimenters to determine when the motions took place without having to rely on either the EMG or IMU sensor data. The project resulted in a prototype wearable sensor shirt that was successfully able to detect consistent muscle activity in seven out of eight EMGs, with the IMU system also functioning properly.
STS Research Project
The STS research project explored the application of the seat belt analogy to a regulatory mandate for Level 4 (or higher) autonomous vehicles. The seat belt analogy was upheld in several major areas, by demonstrating the autonomous vehicle has removable decision-making, that it acts a priori and not a posteriori, and that the technology produces individual and public benefits. For these reasons, it would be valid to create a regulatory mandate using the seat belt analogy as an argument. The most significant counter-argument against the application of the seat belt analogy is that the autonomous vehicle has the ability to produce public harm to a larger degree than a seat belt does. However, when considering the minimizations in traffic accidents and fatalities that would take place, this counter-argument could be considered inconsequential.
When examining autonomous vehicle usage through the seat belt analogy, the argument and analytical approach takes a moral absolutist stance. However, the implications of autonomous vehicles and the coding logic will be dependent on the specific population and country in which the technology is implemented. This would require a stance that factors in moral relativism. Future considerations for research could include a comparative study between countries with different moral emphasis. A comparative approach would present the opportunity to find generalizations that apply to the global population (in terms of preferences for moral outcomes) while also taking into consideration regional moral preferences. These preference differences could have large implications for the way software developers create the algorithms and code that govern autonomous vehicles. Currently, there is not enough data to draw conclusive arguments or analysis.

BS (Bachelor of Science)
Autonomous vehicles, Seat belt analogy, Wearable robotic upper-limb exoskeleton, Sensor array

School of Engineering and Applied Science
Bachelor of Science in Mechanical Engineering
Technical Advisor: Sarah Sun
STS Advisor: S. Travis Elliott
Technical Team Members: Navian Francis, Justin Glassman, Meliha Grbic, Seth Hoisington

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