Research

Soft robotics

Inflatable actuator (soft pneumatic actuator (SPA))

An inflatable wrinkle actuator with fast inflation and deflation responses was proposed to apply it to the wearable soft robots. First, a theoretical model is proposed to develop an actuator that satisfies the design requirements: the desired assistive torque and the foam factor based on the wearability. Second, the inflation and deflation times can be reduced by partially controlling the actuator layers and by designing pneumatic circuits using a vacuum ejector. The developed actuator was applied to a wearable knee suit in order to validate the usability of the actuator in wearable suits

[1] J. Park, J. Choi, S. J. Kim, and J. Kim, “Design of an Inflatable Wrinkle Actuator with Fast Inflation/Deflation Response for Wearable suits,” IEEE Robotics and Automation Letters, vol. 5, no. 3, pp. 3799-3805, 2020.

Soft wearable robotics

1. Wearable sensing suit using soft strain sensor

Wearable sensing sleeve for multi-DOF ankle joint motions using Sim-to-real transfer learning and musculoskeletal simulation was developed by using the capacitive strain sensors ought to its low time-varying property and high linearity. A novel musculoskeletal simulation-based transfer learning approach was proposed to guarantee a fast calibration with small amount of dataset.

2. Portable pneumatic power source for soft wearable robots (collaborated w/ Sangjoon. J. Kim)

We proposed the design of a portable double-piston crank microcompressor, which has a simple structure, static mass of 1.5 kg and does not generate any safety hazards. The design requirements in terms of maximum pressure and flow rate were optimized based on wearable robotic applications. The sound intensity level generated by the developed microcompressor was quite low, which can be used for long-term usage, at maximum flow rate.

Physical human-robot interaction (Phri)

Ground reaction force (GRF) measurement system

1. Outsole-type GRF measurement system

A bendable GRF measurement system that can measure biaxial (vertical and anterior-posterior) GRF without interrupting the natural gait was developed to perform kinetic analysis. The developed small biaxial force sensor is based on the optical sensing mechanism, which is more resistant to large impact than force sensitive resistor (FSR) that is widely used in developing GRF measurement system. After developing the system by the installation of force sensors, it was found that the degree of flexibility of the developed system was comparable to that of regular shoes by investigating the forefoot bending stiffness

[1] Junghoon Park, Sangjoon J. Kim, Youngjin Na, Yeongjin Kim, and Jung Kim, “Development of a Bendable Outsole Biaxial Ground Reaction Force Measurement System,” Sensors, vol. 19, no. 11, p. 2641, Jun. 2019.

[2] Sangjoon J. Kim, Gwang Min Gu, Youngjin Na, Junghoon Park, Yeongjin Kim, and Jung Kim, “Wireless Ground Reaction Force Sensing System Using a Mechanically Decoupled Two-Dimensional Force Sensor,” IEEE/ASME Trans. Mechatronics, pp. 1–1, 2019.

2. Insole-type GRF measurement system

Insole type GRF measurement system with four GRF sensors can measure large vertical GRF and robust to impact, and commercial accelerometer to detect human intention. To keep the user’s motions from being disturbed, GRF and acceleration can be transmitted to PC via Bluetooth. The center of pressure (CoP) from GRF and three axes acceleration (anterior-posterior, medial-lateral and vertical directions) can be measured by the developed device. The system can be applied to the healthcare field and the virtual reality field.

Hand exoskeleton using tendon-driven mechanism

1. Development of an indirect fingertip force sensor

An indirect fingertip force sensor with an open-pad structure was developed to provide users with their own tactile sensations while performing grasping during thumb adduction and flexion, index and middle fingers flexion. The proposed sensor measures the force caused by the expansion of the fingertip tissue by means of two capacitive force sensors attached on both sides of the fingertip.

2. Development of a tendon-driven soft hand exoskeleton

A tendon-driven soft hand exoskeleton was developed with qualitative stability analysis based on unstructured dynamic models. A grip force estimation method was devised based on the relationship that the grip force and the forces exerted on the force sensors at the side walls have.

[1] Junghoon Park, Pilwon Heo, Jung Kim, and Youngjin Na, “A Finger Grip Force Sensor with an Open-Pad Structure for Glove-Type Assistive Devices,” Sensors, vol. 20, no. 1, p. 4, Dec. 2019.

[2] J. Park, P. Heo, Y. Na, and J. Kim, “Qualitative Stability Analysis of Soft Hand Exoskeleton Based on Tendon-driven Mechanism,” International Journal of Precision Engineering and Manufacturing, pp.1-10, 2020.

Page updated

Google Sites

Report abuse