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Position Control (position + control)
Selected AbstractsHierarchy Selection, Position Control, and Orientation of Growing Mesostructures by Patterned Surfaces,ADVANCED MATERIALS, Issue 8 2006Spontaneous hierarchical organization of silica by means of a patterned surface is described, in which the usual coexistence of energetically similar structures is overcome. A patterned substrate is shown to lead to pixel-like, simultaneous growth of a hierarchal assembly involving four structural levels. The individual pixels belong to a new class of circularly organized solids (see figure and cover). [source] Predictive adaptive control of plants with online structural changes based on multiple modelsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2008J. M. Lourenço Abstract The objective of this paper is to present a new algorithm to improve the adaptation rate of a predictive adaptive controller. For that sake, the possible plant dynamic outcomes are covered by a bank of models. Each model is used to re-initialize the adaptive controller every time there is a large change in dynamics. The contribution of the paper consists in the development of a procedure that includes additional models in the bank when found suitable according to defined criteria. The algorithm is demonstrated in a benchmark problem consisting of the position control of two masses coupled by a spring of varying stiffness. Copyright © 2008 John Wiley & Sons, Ltd. [source] Systematic design method of stabilization fuzzy controllers for pendulum systemsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 8 2001Jianqiang Yi A systematic method to construct stabilization fuzzy controllers for a single pendulum system and a series-type double pendulum system is presented based on the single input rule modules (SIRMs) dynamically connected fuzzy inference model. The angle and angular velocity of each pendulum and the position and velocity of the cart are selected as the input items. Each input item is given with a SIRM and a dynamic importance degree. All the SIRMs have the same rule setting. The dynamic importance degrees use the absolute value(s) of the angle(s) of the pendulum(s) as the antecedent variable(s). The dynamic importance degrees are designed such that the upper pendulum angular control takes the highest priority and the cart position control takes the lowest priority when the upper pendulum is not balanced upright. The control priority orders are automatically adjusted according to control situations. The simulation results show that the proposed fuzzy controllers have high generalization ability to completely stabilize a wide range of single pendulum systems and series-type double pendulum systems in short time. By extending the architecture, a stabilization fuzzy controller for a series-type triple pendulum system is even possible. © 2001 John Wiley & Sons, Inc. [source] Collision-free control of robotic manipulators in the task spaceJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 8 2005Miros, aw Galicki This paper addresses the problem of position control of robotic manipulators in the task space with obstacles. A computationally simple class of task space regulators consisting of a transpose Jacobian controller plus an integral term including the task error and the gradient of a penalty function generated by obstacles is proposed. The Lyapunov stability theory is used to derive the control scheme. Through the use of the exterior penalty function approach, collision avoidance of the robot with obstacles is ensured. The performance of the proposed control strategy is illustrated through computer simulations for a direct-drive arm of a SCARA type manipulator operating in both an obstacle-free task space and a task space including obstacles. © 2005 Wiley Periodicals, Inc. [source] Planning and controlling cooperating robots through distributed impedanceJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 6 2002Jérôme Szewczyk This article presents distributed impedance as a new approach for multiple robot system control. In this approach, each cooperating manipulator is controlled by an independent impedance controller. In addition, along selected degrees of freedom, force control is achieved through an external loop, to improve control of the object's internal loading. Extensive stability analysis is performed, based on a realistic model that includes robot impedance and object dynamics. Experiments are performed using two cooperating industrial robots holding an object through point contacts. Force and position control actions are suitably dispatched to achieve both internal loading control and object position control. Individual impedance parameters are specified according to the theoritical stability criterion. The performance of the system is demonstrated for transportation and contact tasks. © 2002 Wiley Periodicals, Inc. [source] Position and force tracking of a two-manipulator system manipulating a flexible beamJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 4 2001Dong Sun This article discusses the issue of hybrid position and force control of a two-manipulator system manipulating a flexible beam in trajectory tracking. Unlike our previous approach of set-point position control in the trajectory tracking, the system coordinates are hard to be regulated to the desired states with nonzero tracking velocities under continuous feedback control. In this study, we design a hybrid position and force tracking controller while using saturation control to compensate for the effect of beam vibration dynamics on the tracking performance. All parameters and states used in the controller are readily available so that the proposed method is feasible to implement. Under the proposed controller, the tracking error asymptotically converges to a predetermined boundary. Simulation results demonstrate the validity of the proposed approach. © 2001 John Wiley & Sons, Inc. [source] Fiber-optic displacement sensor using a multimode bundle fiberMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2008Moh. Yasin Abstract A simple fiber optic displacement sensor based on intensity modulation technique is demonstrated using a bundle multimode plastic fiber as a probe. The sensor consists of a light source, a probe, and photodiode detector. The sensor is capable of measuring displacements of mirror ranging from 0.05 to 2.2 mm using a red light source of wavelength 632.8 nm with maximum output power of 1 mW. The sensitivity of the device is found to be 168.8 mV/mm over 0.05,0.35 mm range and ,29.8 mV/mm over 1.05,2.2 mm range. The sensor is highly sensitive at the front slope and very useful for close distance target. The simplicity of the design, high degree of sensitivity, dynamic range and the low cost of the fabrication make it suitable for applications in industries as position control and micro displacement measurement in the hazardous region. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 661,663, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23147 [source] Today's challenges in quantum dot materials research for tomorrow's quantum functional devicesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2007Richard Nötzel Abstract Size, shape, position control, and self-organized lateral ordering of epitaxial semiconductor quantum dot (QD) arrays are demonstrated. This constitutes the prerequisite for the ultimate control of the electronic and optical properties of man-made semiconductor heterostructures at the single and multiple charge, spin, and photon level, including their quantum mechanical and electromagnetic interactions in view of applications such as quantum information processing and computing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Deterministic self-organization: Ordered positioning of InAs quantum dots by self-organized anisotropic strain engineering on patterned GaAs (311)BPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2009E. Selçuk Abstract Laterally ordered InGaAs quantum dot (QD) arrays, InAs QD molecules, and single InAs QDs in a spot-like periodic arrangement are created by self-organized anisotropic strain engineering of InGaAs/GaAs superlattice (SL) templates on planar GaAs (311)B substrates in molecular beam epitaxy. On shallow- and deep-patterned substrates the respectively generated steps and facets guide the self-organization process during SL template formation to create more complex ordering such as periodic stripes, depending on pattern design. Here we demonstrate for patterns such as shallow- and deepetched round holes and deep-etched zigzag mesas that the self-organized periodic arrangement of QD molecules and single QDs is spatially locked to the pattern sidewalls and corners. This extends the concept of guided self-organization to deterministic self-organization. Absolute position control of the QDs is achieved without one-to-one pattern definition. This guarantees the excellent arrangement control of the ordered QD molecules and single QDs with strong photoluminescence emission up to room temperature, which is required for future quantum functional devices. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||