Simultaneous real-time assessment of sportive pilots' stress and performance related to vehicle behavior, during racing with the DIM professional simulator
Authors: Brisinda D , Savorgnan C , Affanni A , Minen M , Minen D , Fenici R 
Published: October 2021

Abstract

Background
Sports motoring and racing imply high physical and psychological stress, during pre-competition phases and the competition itself. Therefore, there is growing interest of racing teams for new technologies providing real-time monitoring of psychophysiological reactions of pilots to highly-demanding driving and vehicle dynamics, to improve personalized training, while reducing human risks and costs.
Professional Driving Simulators (PDS) are ideal to assess in real-time vehicle dynamics under any kind of programmable virtual driving conditions, but a direct connection with the driver's physiology is still limited. A novel wearable system and software have been developed, providing simultaneous assessment of pilot's stress reactions, by real-time calculation and monitoring of time-variant heart rate variability (TV-HRV) spectral parameters (SP) and of skin potential response (SPR), in correlation with vehicle's dynamics.

Purpose
This study aimed to demonstrate the reliability of the method in detecting the pilot's stress induced by different driving demands.

Methods
10 volunteers (age 26±2.3 years) were enrolled to pilot a racing car under realistic conditions simulated by the DIM® PDS (Vi-grade). The study protocol consisted of 5-minutes baseline rest, sitting in the cockpit; 5-minutes driving along a straight highway without obstacles; 6-minutes of medium-stress slalom between cones, avoiding collision; 8-minutes racing 4 laps on a race track, at maximum possible speed, but avoiding crashes. ECG and SPR signals were acquired (1 Khz sample rate), with the Vi-BioBox connected to textile wearable sensors. A proprietary software was developed to analyze and stream the TV-HRV and SPR data in real-time to WINTAX4 data logging software for automotive racing industry. Real-time assessment of the pilot's stress was based on the integration of transient changes of HRV-SP and of the Root Mean Square value of two SPR signals (SPRRMS). To validate the accuracy of the real-time HRV analysis, all data were analyzed also off-line with Kubios Premium 3.4.1. software.

Results
The Vi-BioBox signals were adequate for real-time calculation and monitoring of transient variations of HRV-SP. A good correlation was found between transient stress-induced increment of pilots' SPRRMS values and the occurrence of driving errors (pink-red spots automatically transferred onto the race track – Figure 1). A good match was found between the real-time HRV values calculated by the VI-BioSoft and their off-line calculation with Kubios (v. 3.4.1 Premium). Two pilots, suffering simulator sickness, had prodromal alteration of cardiac autonomic modulation.

Conclusion
The integration of a Vi-grade PDS with the novel system for real-time calculation and telemetric monitoring of time-variant HRV and SPRRMS provides immediate information about pilot's autonomic response to driving demands and emotional reaction to vehicle's dysfunction, driving errors and bad performance.

Funding Acknowledgement
Type of funding sources: None. Figure 1