Hangue Park

Tongue drive system (TDS) is a tongue-operated, minimally invasive, unobtrusive, and wireless assistive technology (AT) that infers users' intentions by detecting their voluntary tongue motion and translating them into user-defined commands. Here we present the new intraoral version of the TDS (iTDS), which has been implemented in the form of a dental retainer. The iTDS system-on-a-chip (SoC) features a configurable analog front-end (AFE) that reads the magnetic field variations inside the mouth

Cutaneous sensory feedback from the paw pads plays an important role in regulating body balance, especially in challenging environments like ladder or slope walking. Here, we investigated the contribution of cutaneous sensory feedback from the paw pads to balance control in cats stepping on a split-belt treadmill. Fore- and hindpaws were anesthetized unilaterally using lidocaine injections. We evaluated body balance in intact and compromised cutaneous feedback conditions during split-belt locomo

We present a new arch-shaped intraoral Tongue Drive System (iTDS) designed to occupy the buccal shelf in the user's mouth. The new arch-shaped iTDS, which will be referred to as the iTDS-2, incorporates a system-on-a-chip (SoC) that amplifies and digitizes the raw magnetic sensor data and sends it wirelessly to an external TDS universal interface (TDS-UI) via an inductive coil or a planar inverted-F antenna. A built-in transmitter (Tx) employs a dual-band radio that operates at either 27 MHz or

BACKGROUND: Neurotraumas or neurodegenerative diseases often result in proprioceptive deficits, which makes it challenging for the nervous system to adapt to the compromised sensorimotor conditions. Also, in human machine interactions, such as prosthesis control and teleoperation, proprioceptive mismatch limits accuracy and intuitiveness of controlling active joints in robotic agents. To address these proprioceptive deficits, several invasive and non-invasive approaches like vibration, electrica

For teleoperation tasks requiring high control accuracy, it is essential to provide teleoperators with information on the interaction between the end effector and the remote environment. Real-time imaging devices have been widely adopted, but it delivers limited information, especially when the end effectors approach the target following the line-of-sight. In such situations, teleoperators rely on the perspective at the screen and can apply high force unintentionally at the initial contact. This

This paper explores communication methods and frequencies for wireless intraoral electronic devices, by using an intraoral tongue drive system (iTDS) as a practical example. Because intraoral devices do not meet the operating conditions of the body channel communication, we chose radio frequency communication. We evaluated and compared three frequencies in industrial, scientific, and medical bands (27 MHz, 433.9 MHz, and 2.48 GHz) in terms of their data link performance based on path loss and ra

We have developed a real-time closed-loop control system for modulating gait characteristics via electrical stimulation of peripheral nerves in the cat. The system monitors gait metrics and applies appropriate electrical stimulus to peripheral sensory nerves to change the gait metrics in the desired direction. Stimulation parameters are determined by the stimulation controller in real-time based on the measured gait metric, the target gait metric, and the relationship between the stimulus parame

The Tongue Drive System (TDS) is a new minimally invasive, unobtrusive, wireless, and wearable tongue-operated assistive technology (AT) that enables individuals with severe physical disabilities to control environments with their free tongue motion. An array of magnetic sensors wirelessly tracks the position of a magnetic tracer attached to the tongue via adhesives or piercing, and a sensor signal-processing (SSP) algorithm converts a set of tongue gestures to user-defined commands in real time

Tongue Drive System (TDS) is a wireless tongue-operated assistive technology (AT), developed for people with severe physical disabilities to control their environment using their tongue motion. We have developed a new ergonomic headset for the TDS with a user-friendly smartphone interface, through which users will be able to wirelessly control various devices, access computers, and drive wheelchairs. This headset design is expected to act as a flexible and multifunctional communication interface

Tongue Drive System (TDS) is a wireless tongue-operated assistive technology (AT), developed for people with severe physical impediments to control their environments using their tongue motion. We have developed a new intraoral TDS (iTDS) in a form of a dental retainer, which can tightly clasp onto the upper teeth, completely hidden inside the mouth, using commercial off-the-shelf components (COTS). The iTDS retainer was tested by two healthy subjects and their performance was compared with that

This paper presents an inductorless 0.1-1 GHz automatic gain control (AGC) circuit comprised of a variable gain amplifier (VGA), power detector (PD), and comparator. The VGA has a gain control range of -28~23 dB with a 1 GHz 3-dB gain bandwidth using a cascode amplifier with negative capacitance. The PD shows an input power range of -30~20 dBm using an improved unbalanced source coupled pair, which incorporates an output differential amplifier and sink current steering. The AGC circuit produces

We developed a prototype of a neural, powered, transtibial prosthesis for the use in a feline model of prosthetic gait. The prosthesis was designed for attachment to a percutaneous porous titanium implant integrated with bone, skin, and residual nerves and muscles. In the benchtop testing, the prosthesis was fixed in a testing rig and subjected to rhythmic vertical displacements and interactions with the ground at a cadence corresponding to cat walking. Several prosthesis functions were evaluate

The contribution of cervical proprioception, vision, and vestibular feedback to the dynamic head-trunk orientation error in the yaw direction was investigated to further the understanding over the mechanism of coordination among different sensory modalities for dynamic head-trunk orientation. To test the contribution of each sensory modality, individually and together, to dynamic head-trunk orientation, 10 healthy human subjects participated in the extended cervical joint position error test, me

Individuals with unilateral lower limb musculoskeletal and neurological conditions, including prosthetic users, experience asymmetric walking. It may result in undesirable compensations by the body and secondary conditions (osteoarthritis, low back pain, etc.). My goal was to develop a real-time closed-loop control system for a sensing, bone-anchored transtibial prosthesis interfaced with residual peripheral nerves and muscles. The prosthesis and control system would allow users to sense ground