Publications (8)1.5 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: This paper describes development of an activity based, multimodal balance rehabilitation training device. Various sensors can be used, including a force plate, inertial sensors, and depth sensing cameras, and various combinations of visual, auditory and tactile feedback can be configured depending on the rehabilitation task and activity. Tactile feedback is presented via a lightweight belt that is worn on the torso. Generally, visual feedback is only needed at the start of rehabilitation training (task orientation) while tactile feedback may be used to augment balance control. Tactile feedback can be configured as a cue that certain movement targets or limits have been reached or as an immediate indicator of the variance in postural sway. Tactile feedback allows the subject to naturally concentrate on the functional rehabilitation task, and is less reliant on visual or verbal cues.
- [Show abstract] [Hide abstract] ABSTRACT: The objective of this study was to evaluate the effectiveness of a dual-row tactile belt comprising two different types of advanced tactors to communicate both navigation information and incoming alerts, during a waypoint navigation night operations scenario. Navigation information was provided to the Soldier by providing a pulse pattern on the torso corresponding to the direction towards the next waypoint. At the same time, the Soldier received incoming situation awareness alerts regarding threat and robot status indicators. Each Soldier participated in two comparable navigation scenarios, where the task performance with a front-mounted visual map display was used. A tactile assisted interface was also part of the Soldier ensemble, such that the tactile system was turned on during one navigation scenario, and turned off for the other. When using the tactile system, Soldiers reported being more situationally aware of their surroundings and having better control of their weapon. They also navigated more quickly, and very rarely consulted their visual dispay, when the tactile system was turned on.
- [Show abstract] [Hide abstract] ABSTRACT: Development of new multisensory Soldier display systems requires context-driven evaluation of technology by expert users to assure generalizability to operations. The capture of Soldier performance demands is particularly challenging in this regard, as many factors converge to impact performance in actual usage. In this paper, we describe new capabilities for tactile communications that include an authoring system, use of android-driven displays for control and map-based information, and engineering tactors with differing salient characteristics. This allows development of a dual-tactor display that affords a larger variety of tactile patterns for communications, or TActions. These innovations are integrated in a prototype system. We used the system to present navigational signals to combat-experienced soldiers to guide development of tactile principles and the system itself. Feedback was positive for the concept, operational relevance, and for ease of interpretation.
- [Show abstract] [Hide abstract] ABSTRACT: Over time, a wide variety of tactile stimulation devices have been designed and implemented in an attempt to minimize power requirements and weight while simultaneously maximizing the stimulus effect. Consequently, the hardware is widely varied and has specific strengths and weaknesses. This section discusses the basic features universal to particular tactile actuator (tactor) designs and a summary table indicating the key performance characteristics of each technology. In addition, there are several characteristics that must be considered when attempting to optimize the tactile actuator design. When considering the signal itself, it is important to take into account its strength/amplitude, the amplitude range, power consumption, and the frequency range. Ideally, the available frequency range and stimulus amplitude range should match that of the human sensory system (see Chapter 2) and its perceptual characteristics (see Chapter 3). Conversely, the power consumption should be kept to a minimum, especially when there is a need for portability. In addition, it is ideal to reduce the size/weight of the individual tactors, physical discomfort, distortion of the signal, and any sensitivity to contact pressure. Likewise, there is a need to maximize the reliability of the hardware, improve its ruggedness, and provide the option to protect electrical components from water. Lastly, the amount of acoustic energy and electromagnetic radiation should be kept to a minimum. However, it should be noted that some of
- [Show abstract] [Hide abstract] ABSTRACT: An immediate need exists for a portable diagnostic device for the assessment of cortical function, and diagnosis of mTBI. This paper presents initial results using a vibrotactile acuity test for the objective and quantitative diagnosis of acute mTBI suspects. mTBI is hypothesized to involve derangement or damage to the underlying cortical network. In particular, fundamental building blocks of the cortex are changed in such a way as to limit the functional connectivity within and between cortical columns. Our approach is based on sensory illusions that are configured as a test of neural connectivity. Pilot clinical test data showed differences between a small healthy normal group and a concussion group using a sports concussion model.
Conference Paper: Implementing Effective Tactile Symbology for Orientation and Navigation[Show abstract] [Hide abstract] ABSTRACT: The sense of touch is an effective, but underutilized, human communication channel. In this paper we describe our research efforts towards optimizing a minimal tactile array for personal navigation and route guidance. There are several aspects to this problem. From an information transfer viewpoint, the question of tactor array size, dimension, location and display symbology requires careful consideration. Effective tactile display symbology involves providing information in an intuitive manner without adding to the cognitive loading of the user. Tactile information may be presented through spatial, temporal and signal variables. We have recently developed new wearable tactors that offer wide sensory capabilities to provide different “feeling” stimuli. These actuators are non-linear in that the salient characteristics for perception are linked to a complex drive stimulus. We have therefore developed a tactor activation design approach termed “TActions” (Tactile Actions) where patterns or sequence of individual tactile stimuli, each of which has its own characteristics and properties, are used to create tactile display symbology that a user can naturally associate with a particular function. These components provide display design frame work which we have used to demonstrate orientation and navigation.
Article: --TACTILE ACTUATOR TECHNOLOGY
- [Show abstract] [Hide abstract] ABSTRACT: The body's sense of touch is potentially a versatile channel for the conveyance of directional, spatial, command, and timing information. Most practical implementations of vibrotactile systems require compact, light-weight actuators that can be mounted against the body. Eccentric mass motors are widely used for this application, yet their output is limited and the effects of loading on the transducers due to the skin and mounting arrangement have been largely ignored. Conventional linear actuators are well suited as vibrotactile transducers and can provide high output, but are typically limited to laboratory research due to their large size and cost. The effect of loading on various practical vibrotactile transducers is investigated using a skin impedance phantom and measuring the transducer displacement with respect to additional mass loading. Depending on the transducer design, loading can dramatically reduce the vibratory displacement and, in the case of eccentric mass motors, also increase the operating frequency. In contrast, a new linear actuator design can be designed to be almost independent of skin loading, by considering the mechanical impedance of the load and optimizing the transducer contact area.