Chang-Hoi Kim

Trotting gait analysis of a lizard using motion capture

Research into the gait planning of a walking robot is the underlying development of quadruped robots. Despite the efforts in stable gait planning, many walking robots that have been developed thus far do not have enough ability to adapt to uneven territory. In this paper, we acquired the motion data of the trotting lizards using the motion capture equipment and analyzed the gait systematically. In addition, we applied it to the kinematic model of the lizard and acquired the trajectory of each joint through an inverse kinematic solution. Moreover, we proposed the joint space-based gait of the lizard model by approximating the acquired joint trajectory to a sinusoidal function. We verified through the simulation that the proposed gait faithfully follows actual gait of lizards.

Design of a remote control system for maintaining and repairing tasks in NPP

This paper describes the design of a remote control system for maintaining and repairing tasks in a nuclear power plant (NPP). As the remote target tasks, we set up a remote manipulation of the manual operation mechanism of the nuclear fuel changer of the heavy water NPP and remote pipe cutting/welding, which may be necessary in the case of an emergency or dismantling of the NPP. The system to be developed is composed of a master device, a slave robot, and a mobile platform, as well as a telescopic mast that moves the slave robot to the desired position. To effectively perform remote tasks, we designed the architecture of an integrating program. The integrating program has a system components control module, a virtual guide implementing module, and egocentric remote control algorithms. We also designed psychophysics experiment for evaluating the individual technologies and integrated systems.

Development of a Prototype Robotic System for Radiosurgery with Upper Hemispherical Workspace

This paper introduces a specialized robotic system under development for radiosurgery using a small-sized linear accelerator. The robotic system is a 5-DOF manipulator that can be installed above a patient to make an upper hemispherical workspace centered in a target point. In order to determine the optimal lengths of the link, we consider the requirements for the workspace of a linear accelerator for radiosurgery. A more suitable kinematic structure than conventional industrial manipulators is proposed, and the kinematic analysis is also provided. A graphic simulator is implemented and used for dynamic analysis. Based on those results, a prototype manipulator and its control system are under development.

Aerial Working Environment Monitoring Robot in High Radiation Area

This paper describes the development of a robot monitoring an aerial working environment in a high radiation area such as the Calandria face at a PHWR (pressurized heavy water reactor) of a nuclear power plant. The robot consists of three main parts: a mobile platform, a telescopic mast, and a mission tool. To access the target place across the guide rail ditch of a shielding door, the mobile platform is equipped with two front rubber wheels, two rear omni-wheels, and four flippers. The telescopic mast installed on the platform is able to lift up the mission devices to the height of 10 m. The mission devices are a radio hardened camera, a leak detecting sensor, a dosimeter detecting high radiation level, and a RAM operating device of a fuel exchange machine. In addition, a control system considering the emergency was developed.

Trot gait simulation of four legged robot based on a sprawled gait

Lizards with a thin and flexible body can easily pass through a narrow path. Their sprawled gait increases their stability and allows them to overcome obstacles and rough terrain. Therefore, lizard bio-mimetic robots are suitable for reconnaissance and detection. The dynamic modeling of a lizard was carried out by weighing each link of a lizard and constructing its 3D shape using micro-CT scanning. We formulated a periodic sprawled gait which is able to describe the gait of lizards. In addition, we generated an upright gait by altering the gait parameters of the sprawled gait. The sprawled and upright gaits of the dynamic lizard model were simulated with various gait parameters using commercial dynamic analyzing software. The stable gait parameters for the stable trotting were obtained through the simulation.

Relative position measurement method for a live-line work robot

The path of a robot can be preprogrammed for the live-line work of a distributed power line since the procedure for such of a task is predefined. But the reference coordinate of a robot is deviated according to the position of the vehicle and boom it is mounted on. The reference position of a robot should be measured and modified for the planned path in order to preform preprogrammed tasks for a live-line work. In this paper, we propose a relative position measurement method for a robot by using a single image of a camera which is attached to the base of a robot. The intrinsic parameters and extrinsic parameters of the camera can be found since the dimensions of the pin type insulator are known in advance from this image. The validity of the proposed method was tested by a simulation.