HumanintheLoop Assessment of an Ultralight, LowCost Body Posture Tracking Device In rehabilitation, assistive and space robotics, the capability to track the body posture of a user in real time is highly desirable. In more specific cases, such as teleoperated extravehicular activity, prosthetics and home service robotics, the ideal posturetracking device must also be wearable, light and lowpower, while still enforcing the best possible accuracy. Additionally, the device must be targeted at effective humanmachine interaction. In this paper, we present and test such a device based upon commercial inertial measurement units: it weighs 575 grams in total, lasts up to 10.5 hours of continual operation, can be donned and doffed in under a minute and costs less than 290 EUR. We assess the attainable performance in terms of error in an online trajectorytracking task in Virtual Reality using the device through an experiment involving 10 subjects, showing that an average user can attain a precision of 0.66 cm during a static precision task and 6.33 cm while tracking a moving trajectory, when tested in the full peripersonal space of a user.

On the Usability of Consumer Locomotion Techniques in Serious Games: Comparing Arm Swinging, Treadmills and WalkinPlace When we refer to locomotion in Virtual Reality (VR) we subtend a vast and variegated number of investigations, solutions and devices coming from both research and industry. Despite this richness, a consolidated methodology for evaluating the many locomotion techniques available is still lacking. The present paper extends a previous work in which authors performed a user studybased comparison between two common locomotion techniques, i.e., Arm Swinging, and an omnidirectional treadmill with a containment ring. In the study, users were engaged in a realistic immersive VR scenario depicting a fire event in a road tunnel. Remaining adherent to the previously defined methodology, the current work widens the comparison to consider two other locomotion methods (keeping results obtained with the former technique above for reference purposes), namely, a different treadmill constraining the user through a topmounted independent support structure, and WalkinPlace, a technique which allows the user to move in the virtual environment by performing a natural marching gesture by exploiting two sensors placed on his or her legs.