Jong Tae Seo

Modeling and analysis of a biomimetic foot mechanism

Humans and mammals possess their own feet. Using the mobility of their feet, they are able to walk in various environments such as plain land, desert, swamp, and so on. Previously developed biped robots and four-legged robots did not employ such adaptable foot. In this work, a biomimetic foot mechanism is investigated through analysis of the foot structure of the human-being. This foot mechanism consists of a toe, an ankle, a heel, and springs replacing the foot muscles and tendons. Using five toes and springs, this foot can adapt to various environments. A mathematical modeling for this foot mechanism was performed and its characteristics were observed through numerical simulation.

Design of an antagonistically counter-balancing parallel mechanism

Much attention has not been paid to analysis of the open-loop stability for gravity counter-balancing of parallel mechanisms or closed-chain mechanisms. The open-loop stability is crucial especially in passively counter-balanced mechanisms where no actuators are involved. Passive hands-on device is such an example. A general stiffness model is derived for general closed-chain mechanism including counter-weight model. As a measure of the open-loop stability, we employ the determinant of the stiffness matrix. A parallel mechanism having 3 translational DOF (degree of freedom) is employed as an exemplary device. An antagonistically counter-balancing is found the most stable method. We conduct dynamic simulation and experiment to confirm the open-loop stability of the system.

Synthesis of new statically balanced parallel mechanisms

In this paper, a method for type synthesis of several new statically balanced parallel manipulators is presented systematically. Firstly, using the concept of constant potential energy, we propose a statically balanced stackable planar mechanism. Secondly, based on the statically balanced stackable planar mechanism, independent statically balanced limb types with certain constraint are designed. Thirdly, combining specific limbs with different wrench system, we synthesize several n-DOF (degree of freedom) parallel mechanisms.

Design of endoscope holder mechanism and controller for a laryngeal surgical robotic system

The objective of this paper is to describe the endoscope holder mechanism design and the controller configuration for the laryngeal surgical robotic system. This system consists of a master device, a slave device, and a control PC. The endoscope holder mechanism was designed based on a stackable mechanism. The EtherCAT communication was used for overall real-time control of the laryngeal surgical robotic system. The surgeon can remotely locate the slave device using this system.

Development of a Robotic Colonoscopic Manipulation System, Using Haptic Feedback Algorithm

Purpose Colonoscopy is one of the most effective diagnostic and therapeutic tools for colorectal diseases. We aim to propose a master-slave robotic colonoscopy that is controllable in remote site using conventional colonoscopy. Materials and Methods The master and slave robot were developed to use conventional flexible colonoscopy. The robotic colonoscopic procedure was performed using a colonoscope training model by one expert endoscopist and two unexperienced engineers. To provide the haptic sensation, the insertion force and the rotating torque were measured and sent to the master robot. Results A slave robot was developed to hold the colonoscopy and its knob, and perform insertion, rotation, and two tilting motions of colonoscope. A master robot was designed to teach motions of the slave robot. These measured force and torque were scaled down by one tenth to provide the operator with some reflection force and torque at the haptic device. The haptic sensation and feedback system was successful and helpful to feel the constrained force or torque in colon. The insertion time using robotic system decreased with repeated procedures. Conclusion This work proposed a robotic approach for colonoscopy using haptic feedback algorithm, and this robotic device would effectively perform colonoscopy with reduced burden and comparable safety for patients in remote site.

Retractor mechanics in open-surgery

In this study, we investigate a retractor mechanics in open-surgery. Retracts are being used to acquire open space for conducting surgery. It is discovered that regardless of retractors number, retractors should be located at the vertices of regular polygon in order to secure the largest operating space. Based on this result, retractor mechanics that describes the correlation among the operating area, retraction force, and the number of retractors is suggested. The estimated retraction forces based on retractor mechanics match well with experimental data based on the porcine skin.

Balancing arm design for variable payload

This paper describes methodology to design a balancing arm for variable payload. A passive stackable parallel mechanism is employed for this design. Two variables, link length and counter-weight, are considered to cope with variable payload. This mechanism is specifically applied to otologic surgery in which drills with different weight are being used.

A robotic approach for colonoscopy

This paper introduces a robotic approach for colonoscopy. 4 DOF haptic master device and slave device were designed by analyzing the movement of surgeon. The force or torque felt during insertion of the endoscope tube is feedback to the master device for providing the operator with haptic feeling and preventing damage of the inner surface of the large intestine.

A robot design for trans-oral surgery

The objective of this paper is to describe a new design of a trans-oral surgical robot. The trans-oral robotic surgery system consists of a master device and a slave device. Specifically, the concept of stackable mechanism is applied to design both master and slave devices. Using the stackable architecture, counter-balancing can be achieved over the whole workspace and compact design can be made by locating all motors at the base of the robot. Through simulation, the performance of the trans-oral surgical robot is verified.

Path planning of a four-legged robot system for crack diagnosis of rib structure of airplane wings

Crack diagnosis inside of the airplane wing is known necessary to prevent a possible breakage of wings. This work proposes a four-legged robotic system which is able to explore the wing and inspect the crack in the rib structure of the wing instead of human operators. A motion planning algorithm of the four-legged robot is described and a computer simulation is performed to corroborate its effectiveness.