Falls are the leading cause of fatal and non-fatal injuries, particularly for older persons. Imbalance can result from the body's internal causes (illness), or external causes (active or passive perturbation). Active perturbation results from applying an external force to a person, while passive perturbation results from human motion interacting with a static obstacle. This work proposes a metric that allows for the monitoring of the persons torso and its correlation to active and passive perturbations. We show that large changes in the torso sway can be strongly correlated to active perturbations. We also show that we can reasonably predict the future path and expected change in torso sway by conditioning the expected path and torso sway on the past trajectory, torso motion, and the surrounding scene. This could have direct future applications to fall prevention. Results demonstrate that the torso sway is strongly correlated with perturbations. And our model is able to make use of the visual cues presented in the panorama and condition the prediction accordingly.

Fall-related injury is a significant health problem on a global scale and is expected to grow with the aging population. Laboratory-based perturbation systems have the capability of simulating various modes of fall-inducing perturbations in a repeatable way. These systems enable fundamental research on human gait and balance and facilitate the development of devices to assist human balance. We present a robotic, rope-driven system capable of rendering bumps and force-fields at a person's pelvis in any direction in the transverse plane with forces up to 200 N, and a 90% rise time of as little as 44 ms, which is faster than a human's ability to sense and respond to the force. These capabilities enable experiments that require stabilizing or destabilizing subjects as they stand or walk on a treadmill. To facilitate use by researchers from all backgrounds, we designed both a configuration with simpler open-loop force control, and another with higher-performance, closed-loop force control. Both configurations are modular, and the open-loop system is made entirely from 3D-printed and catalog components. The design files and assembly instructions for both are freely available in an online repository.

Soft robotics and pneumatic actuation present opportunities for lightweight wearable haptic devices that provide distributed touch feedback to the skin. Ideally, such devices would be easily donned and doffed, since permanent coverage of a large area of the skin is undesirable. Here we present the design and evaluation of a concept device called HapWRAP: a growing haptic device constructed from flexible low density polyethylene. Controlled air flow through tubes and pouches allows HapWRAP to grow out of a compact housing unit and provide a combination of directional and force feedback to a user. When activated, HapWRAP grows up and around the forearm; its loops form a temporary sleeve. After growth, pneumatic actuators inflate and deflate to stimulate mechanoreceptors in the skin at distinguishable locations. This paper describes the design and manufacturing of HapWRAP, reports its performance metrics, and tests its suitability as a haptic feedback device. Participants were able to interpret force and direction cues from HapWRAP with 92.5% accuracy. These findings suggest that HapWRAP can be successfully used for applications where both force and direction cues are necessary.

WAVES, a Wearable Asymmetric Vibration Excitation System, is a novel wearable haptic device for presenting three dimensions of translation and rotation guidance cues. In contrast to traditional vibration feedback, which usually requires that users learn to interpret a binary cue, asymmetric vibrations have been shown to induce a pulling sensation in a desired direction. When attached to the fingers, a single voicecoil actuator presents a translation guidance cue and a pair of voicecoil actuators presents a rotation guidance cue. The directionality of mechanoreceptors in the skin led to our choice of the location and orientation of the actuators in order to elicit very strong sensations in certain directions. For example, users distinguished a "left" cue versus a "right" cue 94.5% of the time. When presented with one of six possible direction cues, users on average correctly identified the direction of translation cues 86.1% of the time and rotation cues 69.0% of the time.

Wearable haptic feedback devices for virtual reality, human-robot interaction, and motion guidance require lightweight actuators that display clearly discernible cues to the user. These goals motivate the design of WRAP, a wearable, pneumatically actuated haptic feedback device. WRAP displays a variety of tactile sensations to the user by inflating a thermoplastic pneumatic actuator in direct contact with the skin. This paper describes the design and construction of WRAP, shows its effectiveness in indicating direction cues to users, and demonstrates two other appUcations for WRAP in image-guided medical interventions and human-computer interaction. Users were able to identify translation and rotation cues from WRAP with 99.4% accuracy. Our results suggest that WRAP is suitable for a variety of wearable and portable applications in which direction cues are beneficial.

Surgeries involving interaction with soft tissue like the brain need to minimize shear and normal forces that can cause tissue damage or hemorrhage. Other surgeries require the ability to follow a complex, curved path, such as through an intestine or to a kidney stone. This paper presents a soft catheter that has the potential to aid in these challenging cases. The soft catheter is capable of apical extension in which the tip extends while the rest of the catheter remains stationary. This limits shear forces with the environment, easing movement of a body's tip through a constrained space. The soft catheter is pre-formed to patient-specific trajectories, meaning that normal forces against tissue would only arise due to errors between the actual and desired paths; we show decrease in normal force applied to the environment on the order of 100 compared to a standard catheter in a 30 degree bend. Setting the internal pressure allows for control of catheter stiffness, with a 500 times difference over the range of tested pressures. Manual operation to reach a surgical site requires only holding the correct orientation at the entry point into the body and setting the internal pressure of the catheter. This soft catheter could offer two benefits: the ability to apply low tissue interaction forces and reach challenging locations within the body.