This study attempts to apply the principle of Distributed Virtual Environments (DVE) and virtual reality (VR) technologies to Complex Graphics Design System (CGDS) by integrating network computer graphics and VR into a web-based learning environment. VR system especially multi-user systems can benefit from and often require a distributed realization. This study develops a multi-user sculpture graphics system for learning and design. These features of the CGDS system are real-time dynamic flexible and portables. This investigation describes an empirical study that investigated the effect of Complex Graphics Design. The system using the OpenGL is due to the important feature that the system can run at different operate system such as Windows 2000 98 NT Linux Mac…etc. It is necessary to learn and …
This paper presents a realization of compliant motion by a decentralized control in redundant manipulator. Manipulator is divided into several subsystem and each subsystem has virtual impedance in partial workspace. Each system performs autonomously by using virtual impedance and the information transmitted from tip side subsystem. The control system becomes independent from the degree of freedom(DOF) of total system. Furthermore to realize the adaptation against environment the compliant motion of subsystem is introduced. When external force applied to subsystem the reaction torques are estimated by reaction torque estimation observers. The external force is calculated by using the estimated reaction torques. Using the estimated external force compliance motion of …
16:30―16:50
Loop Shaping Issues in Hard Disk Drive Servo System Design
Alessandro Beghi, Roberto Oboe, Paolo Capretta, Università di Padova, Francesco Chrappan Soldavini, STMicroelectronics, Italy
In this paper, the design of Hard Disk Drive (HDD) servo systems based on statespace techniques is considered. In particular, we analyze the performances of discretetime controllers obtained by means of LQG optimal control theory. The key control design issue we address is related to the need of achieving sufficiently high close-loop bandwidth while granting adequate disturbance rejection in the loop gain crossover frequency region. It turns out that the shaping of the sensitivity function is a critical issue, in particular when Run Outs compensation schemes are introduced (e.g., repetitive control schemes). The effectiveness of discrete-time loop transfer recovery techniques (LTR) in achieving a satisfactory loop shaping design starting from an LQG regulator is discussed. The proposed control algorithms are …
A Multi-fingered Hand Control Structure with On-line Grasping Force Optimization
Constant Remond, Véronique Perdereau, Michel Drouin, Université Pierre et Marie Curie, France
Grasp stability in a multi-fingered hand requires an appropriate force distribution between fingers taking into account contact conditions. The optimal solution with either recursive or non linear programming methods usually involves many computations and is very often not suitable for on-line implementation. This paper describes the transformation of this constrained problem into an unconstrained one so that the optimization algorithm finds the optimal solution within a few iterations. Force determination is then included in a hybrid position/force controller to prove the effectiveness of such a solution for updating force references during the grasped object motion.
16:50―17:10
On-line Identification of Hysteresis Functions with Nonlocal Memory
This paper shows that the on-line identification of hysteresis functions with nonlocal memory boils down to a well understood recursive least squares estimation problem if the hysteresis function is modeled as a weighted superposition of extended linear stop operators with fixed parameters. Simulation results show that this technique can be applied to model hysteresis functions in static as well as dynamic systems. In addition this technique has been successfully applied to model the hysteresis behaviour of a piezoelectric actuator. In future work the adaptive compensation of the friction force for micro-displacements will be experimentally validated.
Combined Vision/Force Control at Corners in Planar Robotic Contour Following
Johan Baeten, Joris De Schutter, KU Leuven, Belgium
The accuracy and execution speed of a force controlled contour following task is limited if the shape of the workpiece is unknown. This is even more true when the workpiece contour contains corners. This paper shows how a combined vision/force control approach at corners in planar contour following results in a more accurate and faster executed task. The vision system is used to measure on-line the contour and to watch out for corners. The edge is correctly located by incorporating the compliance of the tool/camera set-up in the contour measurement. A simple corner detection algorithm is presented. Once a corner is detected, the finite state controller is activated to take the corner in the best conditions. Experimental results are presented to validate the approach.
