Affordable Wideband Sensor Coupled Vibrotactile Actuator Systems for Psychophysical Experiments
04 Jul 2016-pp 419-429
TL;DR: Design and response of the piezoelectric actuator system, including the custom built LVDT coupled with the actuator are detailed in this paper, and the developed linear charge-drive is suitable for low-current application ~50i¾źmA, maintaining low EMI and small size.
Abstract: Generation of high-amplitude high-frequency pure-tone mechanical vibrations over a wide frequency range is required in many applications, such as Vibrotactile VT stimulation, material testing and so on. This paper describes development of three different types of actuator systems, pneumatic, electromagnetic and piezoelectric, towards the objective of conducting VT psychophysical experiment above 1i¾źkHz starting from few hundreds of Hz. While the piezoelectric system offers compactness, the 120i¾źW electromagnetic system offers wider bandwidth and is capable of generating suprathreshold stimulus even above 2i¾źkHz. Design and response of the piezoelectric actuator system, including the custom built LVDT coupled with the actuator are detailed in this paper. The frequency response of the tested configuration remains flat over a wide bandwidth till 4i¾źkHz, even at high level of excitation, while generating bursts of 100i¾źµm amplitude sine waves. The developed linear charge-drive is suitable for low-current application ~50i¾źmA, maintaining low EMI and small size.
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TL;DR: The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or her own research.
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TL;DR: This paper presents an alternative approach that enables the surgeon to feel fingertip contact deformations and vibrations while guaranteeing the teleoperator's stability, and implemented this solution on an Intuitive Surgical da Vinci Standard robot.
Abstract: Despite its expected clinical benefits, current teleoperated surgical robots do not provide the surgeon with haptic feedback largely because grounded forces can destabilize the system's closed-loop controller. This paper presents an alternative approach that enables the surgeon to feel fingertip contact deformations and vibrations while guaranteeing the teleoperator's stability. We implemented our cutaneous feedback solution on an Intuitive Surgical da Vinci Standard robot by mounting a SynTouch BioTac tactile sensor to the distal end of a surgical instrument and a custom cutaneous display to the corresponding master controller. As the user probes the remote environment, the contact deformations, dc pressure, and ac pressure (vibrations) sensed by the BioTac are directly mapped to input commands for the cutaneous device's motors using a model-free algorithm based on look-up tables. The cutaneous display continually moves, tilts, and vibrates a flat plate at the operator's fingertip to optimally reproduce the tactile sensations experienced by the BioTac. We tested the proposed approach by having eighteen subjects use the augmented da Vinci robot to palpate a heart model with no haptic feedback, only deformation feedback, and deformation plus vibration feedback. Fingertip deformation feedback significantly improved palpation performance by reducing the task completion time, the pressure exerted on the heart model, and the subject's absolute error in detecting the orientation of the embedded plastic stick. Vibration feedback significantly improved palpation performance only for the seven subjects who dragged the BioTac across the model, rather than pressing straight into it.
163 citations
TL;DR: This paper examines the position control problem of piezoelectric stack actuators and presents a method for overcoming the hysteresis nonlinearity between the applied voltage and the actuator displacement.
Abstract: This paper examines the position control problem of piezoelectric stack actuators and presents a method for overcoming the hysteresis nonlinearity between the applied voltage and the actuator displacement. An inverting charge control circuit is implemented to linearize the stack actuator movement by taking advantage of the linear relationship between charge and displacement. The charge control feedback loop is analyzed in detail. It incorporates an operational amplifier to provide high loop gain, a high-voltage amplifier (HVA) to drive the stack actuator, and a lead compensator to ensure stability. Experiments were conducted to compare the responses of the stack actuator under voltage and charge control. The experimental data show that the charge control provides linear actuator operation from 1 Hz-10 Hz over approximately 35% of the actuator operating range, and from 1 Hz-20 Hz over approximately 19% of the operating range.
128 citations
TL;DR: In this article, the authors measured the pattern of the head vibrations and the velocity of the deformation waves traveling along the bony wall of the skull and found that the maximal sound insulation can be obtained with an ear.
Abstract: In a sound field the head is set into forced vibrations, and the vibrations are sometimes heard by bone conduction. For clinical purposes it is important to know the magnitude of these vibrations of the head so that, in cases of partial deafness, the roles of air conduction and bone conduction can be understood.The pattern of the head vibrations and the velocity of the deformation waves traveling along the bony wall of the skull were measured. For the velocity we found c = 570 m/sec. In the course of the experiments, a new method of calibrating a vibration pick‐up with a sound level meter was developed.It was found possible to construct an earphone that reduces the amount of “cross‐hearing” to a very low value. With this earphone, hearing thresholds can be measured in many cases without using noise to mask the ear with the better hearing, even though the difference between the sensitivities of the two ears is greater than 40 db.It is shown that the maximal sound insulation that can be obtained with an ear...
116 citations
TL;DR: In this paper, the intensity characteristics of signal-averaged receptor potentials in response to sinusoidal displacements were found to be linear at low stimulus levels and to saturate at higher ones.
Abstract: Intensity characteristics that relate receptor- (generator) potential amplitude to vibration amplitude and frequency characteristics that relate either the stimulus intensity required for a criterion response or the phase angle between the stimulus and the receptor potential to vibration frequency have been obtained from isolated pacinian corpuscles removed from cat mesentery. The intensity characteristics of signal-averaged receptor potentials in response to sinusoidal displacements were found to be linear at low stimulus levels and to saturate at higher ones. At the higher levels, an asymmetric full-wave rectification was often found, the degree of which varied among receptors. The receptor-potential waveforms showed a time-dependent hysteresis in response to every stimulus cycle at moderate and high stimulus levels. An average intensity characteristic is given. The measured amplitude-frequency characteristics for a constant magnitude of the receptor potential below the neural spike threshold were found to be U-shaped functions. The averaged (n = 7) amplitude-frequency characteristic generated at a constant criterion response had a best frequency of 370 Hz and a bandwidth of Q3 dB equal to 0.8. The phase-frequency characteristics of the receptor potentials below spike threshold exhibited two populations of responses. Both populations underwent phase changes of about 300 degrees as the vibration frequency was increased from 20 Hz to 1.0 kHz but were separated by 180 degrees. An average (n = 8) phase-frequency characteristic is shown. For a constant neural firing rate, the relationship between receptor-potential amplitude and stimulus frequency was also U-shaped. Several qualitative physiological models are presented in relation to previously reported anatomical evidence (14, 18, 19, 32, 45). For the intensity domain, it is suggested that the cytoplasmic extensions that protrude from the unmyelinated portion of the corpuscle axon into the hemilamellar clefts are responsible for the asymmetric full-wave rectification and the response polarity in the phase-frequency characteristics. It is the asymmetric full-wave rectification and consequent receptor-potential waveforms that produce the 2 spikes/stimulus cycle plateaus in the characteristics relating firing rate to stimulus intensity described in the preceding paper (5). An additional model, based on the recovery of spike threshold, suggests how the plateaus in the firing rate-intensity characteristics (5) are produced. For the frequency domain, three filters in cascade can account for the frequency characteristic obtained with a constant firing rate criterion (see Ref. 5).(ABSTRACT TRUNCATED AT 400 WORDS)
112 citations