Zeungnam Bien

The smart house for older persons and persons with physical disabilities: structure, technology arrangements, and perspectives

Smart houses are considered a good alternative for the independent life of older persons and persons with disabilities. Numerous intelligent devices, embedded into the home environment, can provide the resident with both movement assistance and 24-h health monitoring. Modern home-installed systems tend to be not only physically versatile in functionality but also emotionally human-friendly, i.e., they may be able to perform their functions without disturbing the user and without causing him/her any pain, inconvenience, or movement restriction, instead possibly providing him/her with comfort and pleasure. Through an extensive survey, this paper analyzes the building blocks of smart houses, with particular attention paid to the health monitoring subsystem as an important component, by addressing the basic requirements of various sensors implemented from both research and clinical perspectives. The paper will then discuss some important issues of the future development of an intelligent residential space with a human-friendly health monitoring functional system.

A dynamic gesture recognition system for the Korean sign language (KSL)

The sign language is a method of communication for the deaf-mute. Articulated gestures and postures of hands and fingers are commonly used for the sign language. This paper presents a system which recognizes the Korean sign language (KSL) and translates into a normal Korean text. A pair of data-gloves are used as the sensing device for detecting motions of hands and fingers. For efficient recognition of gestures and postures, a technique of efficient classification of motions is proposed and a fuzzy min-max neural network is adopted for on-line pattern recognition.

A minimum-time trajectory planning method for two robots

A trajectory planning method that ensures collision-free and time-optimal motions for two robotic manipulators with limited actuator torques and velocities is proposed. In terms of parameters defining the positions along the paths of two robots, a two-dimensional coordination space and a maximum velocity curve are constructed to detect collision regions and to plan a time-optimal velocity curve, respectively. An algorithm is then provided for the case of zero initial velocities and a single collision region. A numerical example is included. >

A note on convergence property of iterative learning controller with respect to sup norm

We discuss some undesirable phenomena associated with the λ-norm that is used in the proof of convergence of the iterative learning controller (ILC). Specifically, we first report that huge overshoot may be observed in the output trajectory error, even though the applied learning algorithm has been proved to be exponentially convergent with respect to the λ-norm. This is because of the way in which the λ-norm converges differs from that of the sup norm. We then investigate the relation between the λ-norm and the sup norm. Finally, we present a simple method to remedy the undesirable feature of the conventional ILC.

Study on robustness of iterative learning control with non-zero initial error

In this paper, we investigate some effects of errors in the initial conditions as a learning control algorithm is iteratively applied. We show that the pure error term in the learning control law can be positively utilized to improve the system performance, making it robust against varying initial conditions. For better performance in the face of variable initial conditions, we propose a method of ‘iterative learning control with multi-modal input’. In this proposed control method, an input is synthesized based on the state of initial condition. Numerical examples are given to show the effectiveness of the proposed learning control algorithm.

A fuzzy basis function vector-based multivariable adaptive controller for nonlinear systems

In this paper, a new fuzzy basis function vector (FBFV) approach for the adaptive control of multivariable nonlinear systems is presented. With this method, the nonlinear plant is first linearized. The linearized bias and uncertainties as well as disturbances are assumed to be included in the model structure and their upper bound will be adaptively learned by the FBFV method. The output of the FBFV is used as the parameters of the robust controller in the sense that both the robustness and the asymptotic error convergence can be obtained for the multivariable nonlinear system. The effectiveness of the proposed analysis and design method is illustrated with a simulated example.

A study on the robustness of a PID-type iterative learning controller against initial state error

In this paper, the effect of initial state error in the iterative learning control (ILC) system is studied. First, the previous result that the performance of D-type ILC algorithm can be improved by adding a P-term of error in the algorithm is generalized to PID-type algorithm. Then, robustness is investigated against the initial state error of the generalized ILC algorithm. It is also shown that the trend of error reduction can be effectively controlled by tuning gains of the proposed controller. In order to confirm validity of the proposed ILC algorithm, several examples are presented.

Feature-based visual servoing of an eye-in-hand robot with improved tracking performance

A method is presented for using image features in servoing a robot manipulator. Specifically, the concept of a feature is mathematically defined, and the differential relationship between the robot motion and feature vector is derived in terms of a feature Jacobian matrix and its generalized inverse. The feature-based PID (proportional-integral-derivative) controller is established with three scalar gains and an n*n matrix. By means of various examples, the method of feature-based servoing of a robot proposed is proved to be very effective for conducting object-oriented robotic tasks.<<ETX>>

Virtual decomposition based control for generalized high dimensional robotic systems with complicated structure

This paper presents a systematic adaptive control strategy which can accomplish a variety of control objectives (position control, internal force control, constraints,and optimizations) for the generalized high-dimensional robotic systems (GHDRS) without restriction on target systems. Based on the concept of virtual decomposition by which a GHDRS is virtually decomposed into several objects and base-floating open chains, the motion control problem of the original system is converted into that of each object and that of each open chain, individually, while the internal force control as well as the constraint force control may be performed with respect to each object only. This feature makes it possible to implement the control algorithm of each subsystem in modularly structured hardware which can be integrated to form any specific robot controller dedicated to a specific application. In the sense of Lyapunov, it is declared that the dynamic coupling between every two physically connected subsystems can be completely represented by the so-called virtual power flows (VPFs) at the cutting points between them. Asymptotic stability of the complete system can be ensured by choosing the system Lyapunov function as the sum of all nonnegative accompanying functions assigned for the subsystems. Some possible applications based on the proposed approach are discussed. Finally, computer simulations of two PUMA 560 arms transporting a common object along a prespecified trajectory are carried out to verify the stability and robustness issues of the system.

Robotic smart house to assist people with movement disabilities

This paper introduces a new robotic smart house, Intelligent Sweet Home, developed at KAIST in Korea, which is based on several robotic agents and aims at testing advanced concepts for independent living of the elderly and people with disabilities. The work focuses on technical solutions for human-friendly assistance in motion/mobility and advanced human-machine interfaces that provide simple control of all assistive robotic systems and home-installed appliances. The smart house concept includes an intelligent bed, intelligent wheelchair, and robotic hoist for effortless transfer of the user between bed and wheelchair. The design solutions comply with most of the users’ requirements and suggestions collected by a special questionnaire survey of people with disabilities. The smart house responds to the users commands as well as to the recognized intentions of the user. Various interfaces, based on hand gestures, voice, body movement, and posture, have been studied and tested. The paper describes the overall system structure and explains the design and functionality of some main system components.