An Experimental Setup to Test Dual-Joystick Directional Responses to Vibrotactile Stimuli

Abstract

Abstract-In this paper we investigate the influence of the location of vibrotactile stimulation in triggering the response made using two handheld joysticks. In particular, we compare performance with stimuli delivered either using tactors placed on the palm or on the back of the hand and with attractive (move toward the vibration) or repulsive prompts (move away from the vibration). The experimental set-up comprised two joysticks and two gloves, each equipped with four pager motors along the cardinal directions. In different blocks, fifty-three volunteers were asked to move the joysticks as fast as possible either towards or away with respect to the direction specified by a set of vibrating motors. Results indicate that participants performed better with attractive prompts (i.e. responses were faster and with fewer errors in conditions where participants were asked to move the joysticks in the direction of the felt vibration) and that the stimulation delivered on the back of the hand from the gloves gives better results than the stimulation on the palm delivered by the joysticks. Finally, we analyse the laterality, the relation between correct responses and reaction times, the direction patterns for wrong responses and we perform an analysis on the Stimulus-Response Compatibility and on the training effect.

Experimental Evaluation of Vibrotactile Training Mappings for Dual-Joystick Directional Guidance

“…Experimental tests, consisting in six different tests each composed by 16 random stimuli, have been performed on 38 healthy subjects and the results have been analysed in terms of accuracy and reaction times. With respect to previously published works [28,29], the experiments here presented confirmed that a stimulation on the back of the hand could lead to better results with respect to a stimulation on the palm and that an attractive mapping gives better performance with respect to a repulsive one. Furthermore, the main overall result of this novel study is given by the differences between single and sequential stimuli (Follow me condition): it has been revealed that a slow saltatory pattern could give better results in terms of proportion of correct responses compared to the other tested conditions.…”

“…With respect to the results obtained in previous works [28,29], where only single stimuli have been applied to test dual-joystick directional responses, the main overall aim of this case study is to investigate whether a sequential stimulation could lead to more accurate responses with respect to a single prompt. For this purpose, six different vibrotactile training mappings have been completed by the 38 subjects involved in the experiments: -two tests stimulating the palm of the hand from the actuators placed on joysticks, with attractive (move the joystick toward the vibration) and repulsive (move the joystick in the opposite direction with respect to the vibration felt) single 200 ms vibrotactile stimuli (respectively called Attractive and Repulsive Joystick ); -two tests stimulating the back of the hand from the vibrating motors placed on gloves, with attractive and repulsive single 200 ms vibrotactile stimuli (Attractive and Repulsive Glove); -two tests stimulating the back of the hand with a sequence of three vibrotactile prompts that induce the motion along the direction indicated by the saltatory pattern.…”

“…In fact, in a large number of applications, each joystick degree of freedom (DoF) is mapped to each joint position or velocity of the slave manipulator. Therefore, a heavy mental workload is needed to calculate the inverse kinematics from the DoFs of the slave robot to the DoFs of the joystick [18,25,28,29]. Due to the counter-intuitive and mentally heavy mapping process, subjects operating remote systems by means of joysticks require long training in order to make the telemanipulation system transparent to them.…”

“…The aim of this paper is to investigate effective methods for training subjects in the guidance of two handled joysticks, using vibrotactile prompts. Starting from the results obtained in previously published works [28,29], our motivation to continue the investigation was given by the introduction of the sequential stimulation, already applied in the wrist rotational guidance [16,19]. In particular, we investigate the effects of: (1) stimuli delivered either on the palm or on the back of the hand, (2) with attractive and repulsive prompts, (3) with single and sequential stimuli.…”

An experimental setup to test dual-joystick directional responses to vibrotactile stimuli

“…At the same time, we investigate whether a vibration stimulating the back of the hand is more efficient than a vibration provided by the joystick and stimulating the palm of the hand. This paper is an extended version of a preliminary work presented at IEEE World Haptics Conference 2017 [36]. It is organized as follows: firstly, we provide a detailed exposition of our methods and experimental set-up (Section 2).…”