The Influence of the feedback control of the hexapod platform of the SAAM dynamic driving simulator on neuromuscular dynamics of the drivers

Abstract

Multi sensorial cues (visual, auditory, haptic, inertial, vestibular, neuromuscular) [Ang2] play important roles to represent a proper sensation (objectively) and so a perception (subjectively as cognition) in driving simulators. Driving simulator aims at giving the sensation of driving as in a real case. For a similar situation, the driver has to react in the same way as in reality in terms of ‘self motion’. To enable this behavior, the driving simulator must enhance the virtual immersion of the subject in the driving situation. The subject has to perceive the motion of his own body in the virtual scene of the virtual car as he will have in a real car. For that reason, restituting the inertial cues on driving simulators is essential to acquire a more proper functioning [Kol20]. Simulation sickness has been one of the main research topics for the driving simulators. It was assessed between dynamic and static simulators [Cur7], [Wat32]). For a braking maneuver, [Sie29] stated that if the motion platform is activated the bias in reaching increased levels of decelerations was reduced strongly comparing to inactivated platform case. However, there has been lack in publications of vehicle-vestibular cue conflict based illness rating approach and its correlation with the neuromuscular dynamics for that kind of research. In order to reduce the simulator sickness, the difference between the accelerations through the visual and the vestibular cues have to be minimized (cost function minimization via model reference adaptive control, in this paper). Because of the fact that, this paper addresses the simulator motion sickness as a correlated function of this deviation for the both cues with the perception questionnaires as well as the EMG analysis results for the subjects who joined in those experiments. Due to the restricted workspace, it is not possible to represent the vehicle dynamics continuously with scale 1 to 1 on the motion platform [Moo22]. Nevertheless, the most desired aim is to minimize the deviation of the sensed accelerations between the represented dynamics as realistic as possible depending on the driving task. The perception of the driving is very difficult to evaluate in that context. This is the reason; the motion sickness is not easy to study as well. This research work has been performed under the dynamic operations of the SAAM driving simulator as an open-loop and a closed-loop controlled tracking of the hexapod platform of the SAAM dynamic driving simulator. It is obvious that inertial restitution addresses a significant role to maintain a developed fidelity of the driver behaviors on diving simulators The dynamic simulators are being used since the mid 1960s (Stewart platform) [Ste1] firstly for the flight simulators, then the use has spread to the automotive applications. The utilization scope diversifies from driver training to research purposes such as; vehicle dynamics control, advanced driving assistance systems (ADAS), motion and simulator sickness, etc. The dynamic driving simulator SAAM (Simulateur Automobile Arts et Métiers) involves a 6 DOF (degree of freedom) motion system. It acts around a RENAULT Twingo 2 cabin with the original control instruments (gas, brake pedals, steering wheel). The visual system is realized by an approximate 150° cylindrical view. Within the cabin for the employment of extensive measuring techniques (XSens motion tracker, and Biopac EMG (electromyography) device [Acq10]) prepared, which have been already used with numerous attempts such as sinus steer test, NATO chicane, etc. The visual accelerations of translations (longitudinal X, lateral Y and vertical Z axes) as well as the visual accelerations of roll and pitch, which correspond to the vehicle dynamics, were taken into account for the control. Then the platform positions, velocities and accelerations were controlled and fed back to minimize the conflict between the vehicle and the platform levels. The research question about this paper explains a comparative study between an open and a closed loop controlled platform in order to determine the spent power by the muscles to maintain the vehicle pursuing among the pylons. For the evaluation and the validation procedure [Kim19], [Wat32], [Rey27], [Kem17], [Che5], [Pic25], [Acq1], the scenario driven on the simulator SAAM with an open and a closed loop controlled platform to describe the impact of the feedback control. Some results from a case study will be illustrated in the scope of this research with real time controls of the platform at a longitudinal velocity of 60 km/h. The results of this study will be discussed also statistically to obtain the distribution of the dynamics behavior for a group of the participants. This research has been undertaken at ENSAM Institut Image, in collaboration with RENAULT.