Soft Psychophysiology Ryan Breuer ME Shannon Carey RBEPSY
Soft Psychophysiology Ryan Breuer (ME), Shannon Carey (RBE/PSY), Sam Milender (RBE/ME) Advisors: Professor Jeanine Skorinko (PSY, RBE), Professor Cagdas Onal (RBE, ME) Project Proposal We intend to investigate the feasibility of using soft robotics sensors as physiological measuring devices to increase the accessibility of psychophysiology tools. Theoretical Results Device Design ● Device composed of strain sensors and harness ● Soft Robotics sensors - flexible silicone with microchannels filled with conductive fluid ● Harness - elastic polyester fabric ● Variable sensor resistance is measured by an Arduino Uno via a Wheatstone Bridge Figure 8: Sensor Testing Circuitry Due to the COVID-19 outbreak in the Boston area, we were unable to enact our study on any participants. To determine sensor viability, we instead took the data we derived from our preliminary tests of the sensor itself, and compared it to what we calculated to see in our participants. Background The field of Psychophysiology utilizes quantitative physiological measurements to gain insights into an individual’s psychological state. One such measure, called electromyography (EMG) examines micro-muscular movements through reading electrical impulses beneath the skin. Unfortunately, many of the existing emg devices experience a number of problems, such as high signal noise and prohibitive setups that don’t allow study participants Figure 1 (above): Delsys EMG Sensors on the Hand to move around freely. (https: //delsys. com/) Figure 2 (below): Upper Trapezius EMG Setup While a few companies (https: //www. eegsales. com/BFE/Tapezius_Evalutaion _Suite. htm) have managed to move past these barriers, their products are prohibitively expensive. This prevents labs with less funding from producing work with the same quality as their better-funded counterparts. Our project seeks to use new soft sensing technologies to develop alternatives for EMG devices. We hypothesize that soft strain sensors will be able to offer an inexpensive, straightforward, and safe alternative to EMG in certain applications. This study focuses on the use of the sensor as a measure of subject’s emotional stress via the trapezius. Objectives ● Build soft robotics strain sensors that can measure the contraction of a human participant’s trapezius muscles ● Build a harness to fixture the sensors on a human participant’s back and shoulders ● Design and execute a psychological study to test the effectiveness of these soft robotics sensors when compared to traditional EMG devices Needed Sensitivity Exposure EMG All (%RVE) Maximal Contraction 11. 20% maximal shoulderwidth contraction 5. 80% Exposure Exp. St Dv Person 1 (cm) 10 1 0. 112 0. 058 Person 3 (cm) 20 2 0. 224 0. 116 Voltage Output vs cm Stretch Est. Ohms Figure 3 (left): e. Ga. In soft elastomeric sensor, manufactured in-house Figure 4 (right): Harness with two sensors stretching across trapezius muscles Figure 5 (below): Solidworks models of sensor molds for silicone casting Iterative Design Process ● Harness prototype updated ● Sensor manufacturing process improved ● Tested multiple conductive fluids Exp. St Dv VOut Wheatstone VOut Amplified (x 2) 0 7825714. 00 0. 56 0. 00411405 0. 00822810400 9 1 10783283. 24 0. 42 0. 40133963 0. 8026792686 2 15177142. 86 0. 31 0. 80266103 1. 60532206 5 32410819. 67 0. 15 1. 53011179 3. 060223576 10 74478666. 67 0. 07 2. 02600107 4. 052002139 Maximum Muscular Movement: ● Data derived from: Krantz, G. , et al. (2004). Consistency in Physiological Stress Responses and Electromyographic Activity during Induced Stress Exposure in Women and Men. Integrative Physiological & Behavioral Science, 39(2). https: //doi. org/10. 1007/BF 02734276 ● 0. 112 cm (or 0. 058 cm, at -1 standard deviation Sensitivity: ● Wheatstone bridge and 2 x gain op-amp were mathematically applied ● Sensitivity between 1. 26 and 5. 04 cm/volt, yielding a noise of 0. 0090. 035 cm. Tables 1 -3 (in descending order above): Theoretical Result: Maximum Muscular Movement (1 and 2) and Sensitivity Conclusion Our theoretical results indicate that the soft strain sensor can successfully be applied to measure stress through the trapezius muscle. Preliminary work on a cost analysis suggests that our device is more financially accessible Study Methodology Our study was an approximate replication of previous stress studies. . Its goal was to induce stress YELLOW RED which our sensor would attempt ORANGE RED PINK to measure. PURPLE WHITE BLUE 1. Informed Consent GREEN INDIGO BLACK 2. Attach Soft Strain Sensor and Delsys EMG Sensor 3. Maximal Contraction Test 4. Stroop Color-Word Test 5. Trier Social Stress Test 6. Debriefing Figure 6 (top): Stroop Color-Word Test: participants are asked to name the colors only, ignoring the words Figure 7 (right): Trier Social Stress Test: participants present their qualifications for their dream job https: //www. cambridge. org/core/books/cambridge-handbook-of-psychology-health-and-medicine/stress-andcoping-assessment/0463 B 26 D 15109 D 4 C 6 E 002 DDCDA 55 EF 83/core-reader Further Research ● We would like to see the study executed to have statistical evidence supporting our theoretical calculations. ● Future MQPs: designing better methods of manufacturing the sensors and exploring alternative sensors and methods of fixture for use in the same application. Acknowledgements ● ● ● Professor Angela Incollingo Rodriguez (PSY) Professor Jane Li (ME/RBE) Professor Jeanine Denu Dudle (CE/EE) Ms. Kathleen Milender, MEd. , A&P, Hanover High School, Hanover, NH Yinan Sun, Ph. D Candidate (RBE)
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