• IJIEM

Project Strategy Matching Project Structure to Project Type to Achieve Better Success (pp. 29-40)

Michael Poli, Ilija Cosic and Bojan Lalic
This research looked at a number of real-life projects to determine if a distinct project structure was employed for a specific project type and whether the project structure/project type pairing employed had an effect on project success (i.e., which project structures when employed with which project type led to project success and which did not). Often organizations use only one particular project structure, the matrix, for their projects. Unfortunately one size does not fit all. Form must fit function. Project managers must be able to choose the project structure which is appropriate for their project and thus better position their project to be more successful, to create better business results and achieve the competitive advantage/value that the organization envisioned.

Штампа Ел. пошта

PID Controller Design for A Nonlinear Motion Control Based on Modelling the Dynamics of Adept 550 Robot (pp. 19-27)

Henry Zhang
The multiple link robot is a nonlinear system, in general whose characteristic polynomial is not unique, and whose control schemes depend on particular operating conditions. Among all kinds of controllers used for robot control, nearly 90% is PID controller in the industrial world, not only due to its simplicity and effectiveness, but also to its ability of coping with uncertainties and nonlinearities in the system. Since most of PID controllers are designed based on trial and error method for a black-box plant, for the precision motion control of a robot, it is more desirable to design the PID controller based on the mathematical model of the robot. This paper is dedicated to a PID controller design for a nonlinear motion control based on the mathematical modelling of the dynamics of Adept 550 Robot. The general relationships of the PID controller design on the robotic dynamics and the planned trajectory are derived. The analysis and simulations of its closed loop dynamics indicates its effectiveness in fast and accurate trajectory tracking. The results can be practically generalized to other cases of PID controller design for other robots in the industrial applications.

Штампа Ел. пошта

Distributed Modeling of Manufacturing Activities using Integrative Manufacturing Process Model (pp. 9-18)

Dusan Sormaz
Process planning is one of the key activities for product design and manufacturing. Impact of process plans on all phases of product design and manufacture requires high level of interaction of different activities and tight integration of them into coherent system. In this paper we describe a model for manufacturing activities that allows such integration. The framework for integration is briefly described and the integrative manufacturing process model (IMPM) that considers three dimensions of planning is explained. Manufacturing process model is described as three-dimensional model with the following dimensions: time/order, variability/alternatives, and aggregation. All dimensions are defined and explained as they are related to overall manufacturing planning. The nature of these dimensions is illustrated with several examples. The formal description of the IMPM model is provided usign the graph theory as the basis for the model implementations. Several implementations of the model in Lisp and Java programming languages are are enumerated and applications that generate the model are described with few examples.

Штампа Ел. пошта

Support Vector Regression for Approximation and Generation of Motion in Humanoid Robots (pp. 1-8)

Rakovic Mirko, Borovac Branislav and Nikolic Milutin
This paper analyzes the approximation of human movement which preserves dynamic balance under perturbations using Support Vector Machine (SVM) regression. The quality of approximation was evaluated by two criteria. The first one is deviation of approximated motion from the recorded one, while the other criteria is position of the Zero Moment Point (ZMP), because the dynamic balance has to be maintained. For the human movement, ZMP is constantly within the support area. For the approximated motion applied to humanoid the position of ZMP is calculated. It is possible that the ZMP leaves the support area due to deviation of approximated motion from the recorded one, as well as the deviation of dynamic parameters of humanoid from the real human parameters. Initial motion was recorded from humans and then approximated. Approximated data are applied on humanoid robot model and resulting motion is observed. The resulting motion obtained by SVM regression approximation were compared with cubic spline approximation. The approximated motion and calculated ZMP were then used to train a new SVM. This SVM was then used to generate motion in a humanoid robot based on the desired ZMP position. Comparative analysis of results indicates that there are significant potential applications of SVM regression in humanoid robotics for approximation and generation of motion, as well as for other tasks which require the use of artificial intelligence.

Штампа Ел. пошта