This study proposes an XR support system called "ZenRide" to promote mindfulness meditation as a secondary activity within autonomous vehicles. The system supports mindfulness meditation using a motion platform equipped with a hemispherical screen and a seat installed inside the autonomous vehicle. It consists of three main features: first, the immersive meditation environment, which provides relaxing audio-visual stimuli; second, breathing rate guidance, which uses seat tilts to mimic the sensation of deep breathing and enhance concentration; and third, posture control, which counteracts the sensation of vehicle motion through seat adjustments. A prototype implementing the immersive meditation environment and breathing rate guidance was developed, and preliminary experiments were conducted. The results suggest the potential for breath guidance to provide appropriate rhythms to efectively support mindfulness meditation while driving in autonomous vehicles.
The advancement of autonomous driving technologies
holds the potential to enhance trafic eficiency and
prevent accidents caused by human error [
In particular, at the Society of Automotive Engineers (SAE) automation level 4, manual driving interventions are no longer required within operational design do- uFsiginugreth1e:ZAenpRasidseensgyesrteemngwaigtihnign iannmauintodnfuolmneosussmveehdiictlaet.ion mains, and at level 5, driving becomes entirely unnecessary [2]. As a result, passengers can engage freely in secondary activities without concern about take-over requests. These secondary activities encompass a variety sequent work performance, practicing mindfulness medof options, such as work, entertainment, and sleep, with itation within autonomous vehicles ofers a promising mindfulness meditation standing out as a noteworthy solution to this issue [4]. Passengers could relax and example [3, 4]. alleviate stress during transit, thereby improving their
Mindfulness is the practice of focusing attention performance in post-travel activities. on moment-by-moment experiences, including the five However, existing studies have not suficiently exsenses, posture, and mental activities. Numerous studies plored the feasibility of comfortable mindfulness meditahave demonstrated its efectiveness in reducing stress tion inside autonomous vehicles. Sudden accelerations, and promoting mental and physical well-being [5, 6, 7]. lane changes, and other driving behaviors can afect pasSince commute-related stress can negatively impact sub- sengers’ vestibular and somatosensory systems, making it dificult for them to focus on mindfulness practices.
Addressing these challenges requires not only improvements to the vehicle’s interior environment but also the development of systems that help passengers maintain focus and comfort during the ride.
This study aims to design a support system that facilitates mindfulness meditation for passengers in SAE platform with a hemispherical immersive display and seating to achieve this. This paper presents an overview of the mindfulness meditation support system “ZenRide” (see Figure 1) design and reports the preliminary experimental results. 2. Related Work meditation without disrupting vehicle movements in SAE automation level 4 or higher vehicles. By employing a motion platform with a hemispherical immersive display and seating, the proposed system aims to support mindfulness meditation, thereby reducing passenger stress and enhancing comfort during travel. The significance of this study lies not only in ofering new technical and design approaches for facilitating comfortable mindfulness meditation within autonomous vehicles but also in promoting the idea that secondary activities during travel should be designed to provide benefits beyond merely making eficient use of travel time, positively influencing passengers’ post-travel experiences as well.
Research on passenger comfort and stress reduction in autonomous vehicles has gained momentum in recent years [8, 9, 10, 11], with particular attention given to the potential of mindfulness during travel [3]. In existing studies, comprehensive models have been proposed to capture the factors influencing passenger comfort in an integrated manner [12, 13, 14]. These models primarily 3. Proposed System: ZenRide include factors such as the external environment, vehicle functionalities, user activities and characteristics, and ZenRide is an XR system designed to support mindfulsystem understanding. While these models provide a ness meditation within autonomous vehicles. Since veholistic framework for enhancing the passenger expe- hicle movements during autonomous driving may cause rience within autonomous vehicles, research on factors discomfort and anxiety in passengers, this system aims that directly contribute to improvements in mental health to enhance comfort and facilitate meditation through and stress reduction—particularly in the context of sec- audiovisual stimuli and posture control. ondary activities—remains limited. Autonomous vehicles can use onboard sensors and
In studies focusing on mindfulness within vehicles, route-planning algorithms to calculate and predict the P. E. Paredes et al. explored stress reduction through somatic and vestibular stimuli that passengers may exguided breathing techniques, demonstrating that tactile perience during travel. Based on these predictions, the and auditory interventions efectively lowered drivers’ system tilts the seat accordingly to minimize the impact breathing rates and alleviated stress [4]. However, this of vehicle dynamics and reduce passenger anxiety. As a study primarily targeted drivers, leaving the strategies result, passengers are provided with an environment confor stress reduction among passengers in autonomous ve- ducive to immersive and deeper mindfulness meditation. hicles unexamined. Moreover, virtual reality (VR)-based This system is only feasible in fully autonomous drivrelaxation experiences have shown that synchronized ing. Vehicle behavior depends on moment-to-moment VR content and vehicle movements can have a calming decisions with human drivers, introducing unpredictabilefect, particularly when simulating underwater diving ity that makes preemptive control dificult, unlike au[15]. These simulations were found to reduce passen- tonomous driving. gers’ autonomic arousal during travel. However, the Passengers meditate while seated on a motion platform interaction between vehicle dynamics and mindfulness within the vehicle. This system ofers three key functions meditation has not been adequately explored, and further to enhance the meditation experience. research is needed to investigate how vehicle behavior may afect the ability to concentrate during meditation. 3.1. Immersive Meditation Environment
Additional studies have also examined the potential of mindfulness interventions during commutes, involving This function creates an immersive meditation environexercises and breathing-based techniques. For example, ment through visual content projected onto a hemispherinterventions combining vibrotactile patterns with sim- ical screen and auditory stimuli provided via headphones. ple movements have been proposed to reduce commuter To further enhance immersion and focus, the system emstress [3]. However, these studies again focus primarily ploys noise-canceling headphones to eliminate external on drivers rather than passengers. sounds, including road noise and any noise generated by
While these prior studies have contributed to under- seat adjustments. standing stress reduction and mindfulness in autonomous driving environments, most discussions center around 3.2. Breathing Rate Guidance drivers or VR content, with limited attention to mindfulness meditation specifically tailored for passengers. This This function controls the seat’s tilt to regulate the passtudy seeks to address these gaps by providing an envi- senger’s posture, stimulating both somatic and vestiburonment that allows passengers to engage in mindfulness lar sensation. By mimicking the natural movements of deep breathing—where the upper body reclines during inhalation and returns to its original position during exhalation—the system facilitates a natural deep breathing experience for passengers.
This function manages the motion platform based on the vehicle’s driving route and acceleration or deceleration patterns, reducing the sense of vehicle motion caused by vehicle dynamics. By minimizing stress from movement sensations and alleviating anxiety related to external driving conditions, the system allows passengers to relax and engage more deeply in meditation.
vehicle data such as speed, acceleration, and steering angles.
LiDAR data and vehicle position information are transmitted to Unity, where virtual scenes (e.g., flowing clouds) are generated and projected onto the screen. In the breathing rate guidance function, signals are sent from Unity to the motion platform every four seconds to tilt the seat forward and backward, aligning with the breathing rhythm.
The autonomous vehicle utilized is the "RoboCar Mini This section details the preliminary experiment using a Van" by ZMP Inc. To accommodate the motion platform prototype implementing two functions of the ZenRide and hemispherical display, the two rear rows of seats system: the "immersive meditation environment" and have been removed. "breathing rate guidance." Notably, this experiment did
The motion platform is powered by linear actuators not include the posture control function, meaning that from Koncy (ASIN: B09B4SS6P3). They ofer a 150 mm participants directly experienced the sense of vehicle range, a speed of 15 mm/s, and a load capacity of 800 motion caused by vehicle dynamics. As a result, discrepN. The actuators are controlled by an Arduino Leonardo ancies between the perceived sense of vehicle motion and (microcontroller based on the ATmega32u4). the visual information displayed on the screen could in
Passengers sit on the motion platform and view con- duce motion sickness. To address this, the visual content tent through a custom-made hemispherical display (with was designed to align the flow of clouds—representing an inner diameter of 1.24 m, height of 1.00 m, and depth of the surrounding scenery—with the direction of move0.62 m). Three projectors display immersive 360-degree ment experienced by the participants. Figure 3 shows the visuals, enhancing the sense of presence. The display visual content projected onto the hemispherical screen tilts in sync with the seat, allowing passengers to enjoy during the experiment. the visuals seamlessly without being distracted by the Since VR visuals aligned with the direction of the vehiseat’s movement. Additionally, Bose Noise Cancelling cle’s movement are efective for mindfulness experiences Headphones 700 block out noises from the vehicle and [15], this experiment used the immersive meditation envithe motion platform, further improving the immersive ronment function as a baseline and focused on the breathexperience. ing rate guidance function. Therefore, this preliminary experiment evaluated the efectiveness of the breathing 4.2. Software Architectures rate guidance function in facilitating mindfulness meditation within an autonomous vehicle, focusing on ease of The autonomous driving system perceives the surround- practice and its subjective efect on users. Figure 4 shows ing environment and the vehicle’s position, plans the the driving route. route, and controls acceleration, braking, and steering.
The system employs the open-source Autoware.AI plat- 5.2. Experimental Conditions form, which uses LiDAR data to generate maps of the surroundings and estimate the current position. Based This experiment employed a within-participants design. on this information, the system generates a route that Participants first experienced the breathing rate guidthe vehicle follows. The CAN bus collects and controls ance (w/ BRG) condition to get used to the system. To
assess their impressions during the experiment: • Emotion Questionnaire: We used the Afect Grid [16] to assess emotions along two axes. In this study, we defined them as valence and arousal. Participants were instructed to rate each question on a nine-point scale, ranging from one (negative, passive) to nine (positive, active). Additionally, to evaluate focus levels during the experiment, participants were asked, following a similar study [4], to rate their level of focus on an 11-point scale, ranging from zero (low focus) to ten (high focus). • Workload Questionnaire: National Aeronautics and Space Administration Task Load Index (NASA-TLX) [17] was used to assess participants’ workload.
Nara Institute of Science and Technology (approval number: 2024-I-9) and conducted in accordance with the institution’s ethical guidelines. Before the experiment, participants were briefed on its objectives and procedures.
Participants first boarded the autonomous vehicle, fastened their seatbelts, and put on headphones. They then completed a pre-experiment SSQ questionnaire. To familiarize themselves with the autonomous driving experience, participants first underwent the breathing rate guidance (w/ BRG) condition, which served as the baseline for the overall experience assessment.
Next, participants experienced both conditions in a randomized sequence, answering the same questionnaires after each condition. Finally, they completed the SSQ once more and participated in an oral interview, during which they elaborated on their impressions of the overall experience.
The emotion questionnaire results present scores for valence and arousal. According to the Afect Grid, under the w/ BRG condition, the mean scores ± SD were 6.86 ± 2.10 for valence and 5.13 ± 2.36 for arousal. In contrast, under the w/o BRG condition, the mean scores ± SD were 6.25 ± 2.05 for valence and 5.00 ± 2.51 for arousal. We conducted wilcoxon signed-rank test and we did not find significant diferences: W = 3.5, p = 0.258 for valence, W = 10.0, p = 0.915 for arousal.
The results of the questionnaire on focus levels during the experience indicate that, under the w/ BRG condition, the mean score ± SD was 7.00 ± 1.31. Under the w/o BRG condition, the mean score ± SD was 6.13 ± 1.81. We conducted wilcoxon signed-rank test and we did not find significant diferences: W = 7.5, p = 0.268. were found due to the small number of participants, the distribution of scores suggested the potential for the breathing rate guidance function to provide passengers with an appropriate breathing rhythm, facilitating their engagement in meditation.
This research demonstrates the potential of autonomous driving technology to ofer novel relaxation experiences, contributing to the future design of vehicle well-being environments. However, several limitations must be acknowledged. In future work, we plan to implement the posture control function to counteract the sense of vehicle motion and make it easier for passengers to engage in meditation. Additionally, to evaluate the efectiveness of ZenRide not only subjectively but also objectively, it will be essential to conduct large-scale evaluation experiments utilizing biometric sensors.
ber JP24K17238, Hoso Bunka Foundation. We also would like to thank Prof. Hirokazu Kato (Interactive Media Design Laboratory, NAIST) for supporting and advising us as part of the sub-research project.
Motion sickness in the vehicle was evaluated using SSQ before and after the experiment. Before the experiment, the mean scores ± SD were 13.1 ± 19.04 for Nausea, 11.4 ± 21.44 for Oculomotor, 8.7 ± 16.53 for Disorientation, and 124.1 ± 181.63 for the Total Score. After the experiment, the mean scores were 11.9 ± 13.24 for Nausea, 10.4 ± 12.11 for Oculomotor, 15.7 ± 20.29 for Disorientation, and 142.1 ± 161.41 for the Total Score.
In this study, we examined how breathing rate guidance through seat tilting supports mindfulness meditation in an autonomous vehicle, where visual influence from the external driving environment was blocked using a hemispherical screen. Although no significant diferences and emerging technologies, IEEE access 8 (2020) pp. 27–32.
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