Jihong Lee

To improve limitations of fuzzy PI controller especially when applied to high order systems, we propose two types of fuzzy logic controllers that take out appropriate amounts of accumulated control input according to fuzzily described situations in addition to the incremental control input calculated by conventional fuzzy PI controllers. The structures of the proposed controller were motivated by the problems of fuzzy PI controllers that they generally give inevitable overshoot when one tries to

Regarding the dexterousness measure of robot manipulators, two geometric tools, manipulability ellipsoids and manipulability polytopes, are examined and compared with each other. Even though the manipulability ellipsoid approach is the most widely used techniques, it is shown that the manipulability ellipsoid does not transform the exact joint velocity constraints into task space and so may fail to give exact dexterousness measure and optimal direction of motion in task space. After showing that

We study the role of incomplete information and outside options in determining bargaining postures and surplus division in repeated bargaining between a long-run player and a sequence of short-run players. The outside option is not only a disagreement point but reveals information privately held by the long-run player. In equilibrium, the uninformed short-run players' offers do not always respond to changes in reputation and the informed long-run player's payoffs are discontinuous. The long-run

SUMMARY A collision-free trajectory control for multiple robots is proposed. The proposed method is based on the concept of neural optimization network. The positions or configurations of robots are taken as the variables of the neural circuit, and the energy of network is determined by combining various functions, in which one function is to make each robot approach to its goal and another helps each robot from colliding with other robots or obstacles. Also a differential equation of the circui

In this paper we propose a set of techniques for a real-time motion capture of a human body. The proposed motion capture system is based on low cost accelerometers, and is capable of identifying the body configuration by extracting gravity-related terms from the sensor data. One sensor unit is composed of 3 accelerometers arranged orthogonally to each other, and is capable of identifying 2 rotating angles of joints with 2 degrees of freedom. A geometric fusion technique is applied to cope with t

Herein is proposed a concise algorithmic procedure for deriving a minimum l ∞ -norm solution of the system of consistent linear equations Ax = b , where A is a m × n matrix, b is given as a m ×1 vector and x is a n ×1 unknown vector. The proposed algorithm is developed based on the geometrical analysis of the characteristics of the minimum infinity-norm solution. The proposed algorithm is well-structured so that it may be implemented easily through simple linear algebraic manipulation. For the c

This paper examines repeated implementation of a social choice function (SCF) with infinitely lived agents whose preferences are determined randomly in each period. An SCF is repeatedly implementable in Nash equilibrium if there exists a sequence of (possibly history-dependent) mechanisms such that its Nash equilibrium set is nonempty and every equilibrium outcome path results in the desired social choice at every possible history of past play and realizations of uncertainty. We show, with minor

A low cost motion capture system for the human body is handled. This system is based on low cost accelerometers. By extracting the gravity-related term from sensor data, we relate the sensor data with body configuration in real-time. One sensor unit is composed of 3 accelerometers and is capable of identifying 2 rotating angles of joints with 2 degrees of freedom. A geometric fusion technique is applied to cope with the uncertainty of sensor data. A practical calibration technique is also propos

A numerical trajectory planning method is proposed which ensures collision-free and near time-optimal motions for two robotic manipulators with limited actuator torques and velocities. Constraints on accelerations of the robots that are derived from the limited torques of actuators are transformed to the constraints on the curvatures of the coordination curve in coordination space. A dynamic programming technique is then provided on the discretized coordination space to derive a collision-free a

In this paper, the analysis of manipulability of robotic systems comprised of multiple cooperating arms is considered. Given bounds on the capabilities of joint actuators for each robot, the purpose of this study is to derive the bounds for task velocity achievable by the system. Since bounds on each joint velocity form a polytope in joint-velocity space and the task space velocity is connected with joint velocity through Jacobian matrices of each robot, the allowable task velocity space, i.e. v

To run safely and carry out the mission, a mobile robot should identify types, physical and/or geometric characteristics of terrains on which the robot runs. In this paper, we designed and implemented a mobile robot for collecting contact sensor data that come from the reaction between ground and tires, and then collect sensor data from four experimental terrains. After analyzing the collected data and the physical reaction, we suggested a new method for terrain feature extraction and terrain id