Hyung-Kew Lee

Evaluation of human tangential force input performance

While interacting with mobile devices, users may press against touch screens and also exert tangential force to the display in a sliding manner. We seek to guide UI design based on the tangential force applied by a user to the surface of a hand-held device. A prototype of an interface using tangential force input was implemented utilizing a force sensitive layer and an elastic layer and used for the user experiment. We investigated user controllability to reach and maintain target force levels and considered the effects of hand pose and direction of force input. Our results imply no significant difference in performance when applying force holding the device in one hand and in two hands. We also observed that users have more physical and perceived loads when applying tangential force in the left-right direction compared to the up-down direction. Based on the experimental results, we discuss considerations for user interface applications of tangential-force-based interface.

Role of combined tactile and kinesthetic feedback in minimally invasive surgery.

Haptic feedback is of critical importance in surgical tasks. However, conventional surgical robots do not provide haptic feedback to surgeons during surgery. Thus, in this study, a combined tactile and kinesthetic feedback system was developed to provide haptic feedback to surgeons during robotic surgery.

Tactile display with tangential and normal skin displacement for robot-assisted surgery

This paper proposes a tactile display providing both shear and normal feedback to the fingertip for generating three-axis tactile feedback during teleoperation of a surgical robot. The display is composed of five balloons actuated by controlling the pneumatic pressure. The implemented display is 18 mm × 18 mm × 15 mm. This size is suitable for mounting the display onto the master controls of a surgical robot. The maximum normal and shear displacements are 2 and 1.3 mm, respectively. The proposed tactile display may provide perceivable stimuli to a human finger pad in all five directions: normal, distal, proximal, radial, and ulnar. This paper also reports on the results of psychophysical measurement of the minimum perceivable movement of the developed tactile display for each of the five directions. Graphical Abstract

Three-axis tactile display using PDMS pneumatic actuator for robot-assisted surgery

This paper proposes and demonstrates the 3-axis tactile display actuator using PDMS pneumatic balloons for a robot assisted surgery system. Inflated balloons on the upper surface generate normal forces to a fingertip. In addition, the lateral actuation by side balloons in 2-axis generate shear force to an operator. This operation is suitable for mounting on the operators fingers for normal and shear force feedback from a surgical robot. All polymer lightweight pneumatic tactile actuator designed to display forces at a grasp mounted on a robot arm in the robot assisted surgery system. Through this actuator, we are able to solve the problem of physical isolation reported in previous references and provide virtual surgery environment to a surgeon.

Microfabrication of Three-Axis Tactile Feedback Actuator for Robot-Assisted Surgery

In this paper, we propose and demonstrate a three-axis tactile feedback actuator using pneumatic balloons for human perception applications such as robot-assisted surgery systems. A tactile actuator is composed of a center structure having four balloons, sidewalls with one lateral balloon on each sidewall, and a bottom structure supporting the center structure. We fabricated the proposed device using flexible poly(dimethylsiloxane) and hard polyurethane with final dimensions of 18 ×18 ×18 mm3. The four balloons on the center structure produce normal tactile display during pneumatic-pressure-assisted inflation. The lateral movement of the center structure driven by sidewall balloons generates a shear tactile display on fingertips. The center deflections of the circular and rectangular balloons were calculated and measured experimentally.

Voltage linearity evaluation for a high-speed digitizer adopted to a quantum sampling voltmeter

We report the linearity evaluation for a high-speed digitizer NI 5922, which is adopted to a quantum sampling voltmeter. The evaluation has been carried out for three units of the digitizer using a reference voltmeter with a 14-bit arbitrary waveform generator as a dummy voltage source. The three units show totally different behaviors in terms of the voltage linearity which might be described with different polynomial functions of input voltage. In the conference, we will present results of the linearity evaluation for the three units using a programmable Josephson voltage standard.

The effect of humidity on the calibration of air-type capacitance standards

This paper describes our observation of the effect of humidity on a four-terminal-pair (4TP) air capacitance standard set. A standard set (Agilent 16380A) has been monitored four fourteen days at 1 kHz frequency using an AH 2500A capacitance bridge. Consistent increment of measured capacitance was observed for all the capacitors in the set as the humidity increases. In addition, the analysis on the humidity-dependent capacitance reveals that the capacitance value follows the humidity changes with a delay of about 0.7 day.

Uncertainty evaluation using the Monte-Carlo method for the calibration of four terminal pair air capacitance standards

We developed a calibration software based on the Suzuki method for the calibration of a commercial four terminal pair air dielectric capacitance standard. The uncertainty of the calibration has been evaluated using the Monte-Carlo method. The calibration results showed good agreement with those of Keysight technologies.

Calibration of capacitance in the frequency range up to 1 MHz

This paper describes two different ways to calibrate the capacitance in the high frequency range up to 13 MHz. First, a dual source bridge was configured using two voltage sources and then the ratio of two capacitors was measured in the frequency range from 1 kHz to 1 MHz. The second method known as the Z-matrix method, allowed us to measure the capacitance value up to 13 MHz. The measured values were compared with the reference values calibrated by the PTB and Agilent Technologies, respectively, and they were also compared with each other. The cross-checks showed that both methods are reliable to an order of 10-5 at 1 MHz.