Evaluating the Efficacy of Friction Modulation for Guidance for Blind Individuals

Abstract

The emergence of tactile technologies has paved the way for addressing various challenges. Tactile sensing is especially vital for the blind and visually impaired. This study investigates how tactile feedback can enhance mobility and independence among individuals in this community. In today’s touchscreen-dominated world, accessibility remains a critical concern for those who are visually impaired, as touchscreens lack the tactile guidance necessary for effective touchscreen use. In addition, it is investigated if the guidance is useful for orientation. Our innovative approach employs a directional friction modulation rendering method, aiding users in finger movement and orientation. The efficacy of the tactile directional cue will be assessed for a tracking task and an orientation task. The tactile cue’s shape is determined by the parameter σ, which we optimize in our research. Additionally, in the orientation experiment, we explore the impact of different Field of Feeling ranges, representing the maximum perceivable angles on the actuated glass plate. Our methodology involves blindfolded participants in experiments assessing their ability to interpret and respond to tactile cues generated by an ultrasonic friction modulation device. We use quantitative measures, including response time and directional accuracy, and qualitative feedback from questionnaires to capture participants’ experiences with the tactile feedback system. Our findings reveal fascinating insights into the influence of σ and the Field of Feeling. On average the paths were tracked with an error of 9.84 mm. Smaller σ values correlate with improved tracking performance, as evidenced by the lower root-mean-square error between the finger and the reference path. This relationship is described using a logistic function. The directional friction modulation rendering method was shown to be viable for finding the reference angle. On average, this was achieved in 10.79 seconds with a manageable error of 6.28 ◦ . Specific differences between the tested values for σ were not found. In contrast, the Field of Feeling’s influence on the results appears more pronounced. A broader Field of Feeling leads to quicker decision times when at the reference angle. These outcomes shed light on the feasibility and effectiveness of ultrasonic friction modulation as a tactile feedback mechanism for enhancing the independence of blind individuals. Furthermore, the successful integration of this technology holds the potential to revolutionize electronic surface haptic devices for a wide range of users.