A haptic direction indicator using the gyro effect

Abstract

The preliminary study described in this paper is about the assessment of the control parameters of a non-grounded haptic device giving kinaesthetic stimuli to indicate to the user a direction to follow to reach a target location. The haptic sensation is created by tilting one or more rotating flywheels along an axis, controlling the direction and the amount of tilt, the velocity of the tilt (during the pulse and the repositioning of the flywheel), the frequency of pulses. The current prototype has only one flywheel and is able to tilt along a single axis, thus indicating only “right” or “left” direction. The experiments performed with the prototype allowed us to define a set of requirements (torque produced, duration of the stimuli) for a more complex prototype (2 flywheels and 2 DOF) to be developed and tested as future work

Development and Experimental Validation of a Haptic Compass Based on Asymmetric Torque Stimuli

“…• The Binary Identification's success rate, which assesses whether the correct direction was taken at the beginning, is comparable to the two-alternative forced choice test condition used in [19], [21]. • The Task Time, which is the total time to succeed at the orientation task.…”

“…This phenomenon seems in contradiction with the literature [21] and is not reflected in the binary identification results. A possible cause of the performance decline at high torques is the use of a constant ratio between the signal and the washout τ/τ w = 4, proposed by [19] as most effective with τ ≤60 mNm and τ w ≤ 17 mNm. However, when using higher torques, keeping this constant ratio causes washout torques to exceed the sensory threshold, thereby disrupting the illusion produced by the asymmetry.…”

“…The perceived directional torque is attributed to the nonlinear relationship between perceived acceleration and physical acceleration [9]. One of the particularities of the proposed device is that it uses haptic torques with a higher range of frequencies than those reported in the literature (0.25 − 30 Hz compared to up to 3 Hz in [19] [21]). …”

“…An issue faced with ungrounded torque devices is that stimulus exposition time is limited by the actuators. This problem is avoided by using the approach of pseudo-attraction, as used for torques by [19], [20] and [21].…”

Actuated Shear: Enabling Haptic Feedback on Rich Touch Interfaces

“…However, rich touch interactions still lack proper feedback [4]. There is much research effort on how feedback on touch interfaces can be improved, e.g., near-surface feedback [2], or tactile feedback using air [11]. These approaches are mostly concerned to guide the user's touch input.…”