Jung Hwa Bae

Mr-compatible biopsy needle with enhanced tip force sensing

We describe an instrumented biopsy needle that provides physicians the capability to sense interaction forces directly at the tip of the needles inner stylet. The sensors consist of optical fiber Bragg gratings (FBGs), and are unaffected by electromagnetic fields; hence the needle is suitable for MR-guided procedures. In comparison to previous instrumented needles that measure bending strains, the new design has additional sensors and a series of micro-machined holes at the tip. The holes increase strain sensitivity to axial forces, without significantly reducing the stiffness or strength. Axial loads of 10 mN can be detected with flat response from 0-200 Hz. A comparison of the dynamic forces measured with the needles sensors and those obtained using an external force/torque sensor at the base shows that the enhanced tip sensitivity is particularly noticeable when there is significant friction along the needle sheath.

Detection of Membrane Puncture with Haptic Feedback using a Tip-Force Sensing Needle.

This paper presents calibration and user test results of a 3-D tip-force sensing needle with haptic feedback. The needle is a modified MRI-compatible biopsy needle with embedded fiber Bragg grating (FBG) sensors for strain detection. After calibration, the needle is interrogated at 2 kHz, and dynamic forces are displayed remotely with a voice coil actuator. The needle is tested in a single-axis master/slave system, with the voice coil haptic display at the master, and the needle at the slave end. Tissue phantoms with embedded membranes were used to determine the ability of the tip-force sensors to provide real-time haptic feedback as compared to external sensors at the needle base during needle insertion via the master/slave system. Subjects were able to determine the position of the embedded membranes with significantly better accuracy using FBG tip feedback than with base feedback using a commercial force/torque sensor (p = 0.045) or with no added haptic feedback (p = 0.0024).

Haptic skin stretch on a steering wheel for displaying preview information in autonomous cars

Lateral skin stretch is a promising technology for haptic display of information between an autonomous or semi-autonomous car and a driver. We present the design of a steering wheel with an embedded lateral skin stretch display and report on the results of tests (N=10) conducted in a driving vehicle in suburban traffic. Results are generally consistent with previous results utilizing skin stretch in stationary applications, but a slightly higher, and particularly a faster rate of stretch application is preferred for accurate detection of direction and approximate magnitude.

Display of needle tip contact forces for steering guidance

An MR-compatible biopsy needle stylet is instrumented with optical fibers that provide information about contact conditions between the needle tip and organs or hard tissues such as bone or tumors. This information is rendered via a haptic display that uses ultrasonic motors to convey directional cues to users. Lateral haptic cues at the fingertips improve the targeting accuracy and success rate in penetrating a prostate phantom. Although the original intent was for haptic cues to match the direction of contact forces and needle bending, more consistent results were obtained by using the cues as steering guidance (opposite to contact forces); accordingly this convention was adopted for the user experiments reported.

Haptic feedback of membrane puncture with an MR-compatible instrumented needle and electroactive polymer display

We present results of experiments with a haptic feedback device that imparts tangential deformations to the fingertips for displaying changes in force experienced by an MR-compatible optically-instrumented biopsy needle. The display is actuated using multiple layers of MR-compatible electroactive polymers stretched in a plastic frame. Users can use the device to sense events such as membrane puncture, as the needle is driven through a tissue phantom, with 98.9% reliability.

Comparing haptic and audio navigation cues on the road for distracted drivers with a skin stretch steering wheel

A steering wheel modified to produce lateral skin stretch provides perceptible cues in a vehicle being driven on the road. We conducted tests to determine whether drivers can correctly perceive and react to skin stretch navigation cues. Additionally, we compare skin stretch feedback to audio navigation cues during an auditory N-back distraction task simulating a phone call. Results show a statistically significant difference (p-value = 0.044) between haptic (98.5%) and audio feedback (96.6%) in navigation accuracy and in N-back response accuracy (haptic = 89.9%, audio = 87.2%, p-value = 0.047).