Force Coordination of a Discretely Actuated Parallel Array

2000 ◽  
Author(s):  
Po-hua Yang ◽  
Kenneth J. Waldron
Keyword(s):  
Force Control ◽  
Simplified Model ◽  
Generator System ◽  
Parallel Array ◽  
Force Coordination ◽  
The Subject ◽  
Discrete Manner ◽  
Force Generator ◽  
Pneumatic Cylinders ◽  
Motion Generator

Abstract An array of two-state actuators, i.e. a bundle of binary actuators acting in parallel, can be regarded as a simplified model of biological muscle. The subject of this paper is to investigate the properties of a wrench generator system which is composed of a bundle of pneumatic cylinders connected between an output member and base. Each actuator is postulated to operate in a discrete manner. The parallel array is viewed as a programmable force generator, rather than as a motion generator. The force control problem of this kind of system is not straightforward, since it requires a boolean solution. In this paper, we will propose and explore three possible methods for controlling the force generation of a discretely actuated parallel array.

Interfacial Phases on Giant Unilamellar Vesicles

2012 ◽  
Author(s):  
Yanfei Jiang ◽  
Guy M. Genin ◽  
Srikanth Singamaneni ◽  
Elliot L. Elson
Keyword(s):  
Lipid Vesicles ◽  
Model System ◽  
Simplified Model ◽  
Membrane Rafts ◽  
Domain Formation ◽  
Enveloped Viruses ◽  
Cellular Processes ◽  
Pathological Conditions ◽  
Signaling Mechanisms ◽  
The Subject

Lipid nanodomains in cell membranes are believed to play a significant role in a number of critical cellular processes (Elson, et al., 2010). These include, for example, replication processes in enveloped viruses such as bird flu and HIV and signaling mechanisms underlying pathological conditions such as cancer. Due to the potential for developing new disease treatments through the control of these membrane rafts, the biophysics underlying their formation has been the subject of intense study, much of this focused on domain formation in giant unilamellar lipid vesicles (GUVs), a simplified model system.

Escarpment retreat on a viscoelastic lithosphere 

2021 ◽  
Author(s):  
Gregory Ruetenik ◽  
Robert Moucha
Keyword(s):  
Significant Role ◽  
Landscape Evolution ◽  
Viscoelastic Behavior ◽  
Simplified Model ◽  
Viscoelastic Response ◽  
Isostatic Rebound ◽  
Erosional Unloading ◽  
The Subject

<p>Rift escarpments have long been the subject of coupled geodynamic/landscape evolution studies.  Many of these studies have shown that the flexural unloading response of the lithosphere plays a significant role in the rate of divide migration and the longevity of the escarpment topography, with lower elastic thickness values allowing for more localized isostatic rebound of the lithosphere in response to erosional unloading. However, rift escarpments are thought to last hundreds of millions of years, and therefore the lithosphere may exhibit viscoelastic behavior on this timescale.  Here we present a simplified model of a viscoelastic response to erosional unloading during escarpment evolution, and show that this drastically alters the behavior of the escarpment system.  Specifically, the escarpment retreat rate is significantly reduced, and topography maintained, when compared to a purely flexural model. Additionally, the area in front of the retreating the scarp (i.e., seaward of the scarp) experience delayed uplift response and topographic rejuvenation many millions of years after the divide passes.      </p>

Force and Position Control of the Pneumatic Cylinders through a Microscope with a CCD Camera

2013 ◽  
Vol 284-287 ◽  
pp. 1856-1861
Author(s):  
Hung I Chen ◽  
Ming Chang Shih
Keyword(s):  
Control System ◽  
Force Control ◽  
Position Control ◽  
Fuzzy Controller ◽  
Target Position ◽  
Ccd Camera ◽  
Experimental Results ◽  
Control Interface ◽  
Force Control System ◽  
Pneumatic Cylinders

In this paper, the pneumatic driven manipulation system is driven by the pneumatic cylinders. The proposed system is built by the designed pneumatic force control system and the microscope, which is integrated with the control interface. Firstly, the characteristics of the pneumatic force control system are measured as the proportional pressure control valve. In accordance with these nonlinear characteristics, a self tuning fuzzy controller with a dead zone compensator is designed to improve precision of the pneumatic force control system. From experimental results, the force error can be controlled within ±1 mN. Next, the real-time image is captured by the microscope with a 1/2 type CCD camera. Through designed image processing, image tracking and image recognition, visual image is used to define the position a probe tip. The distance between the target position and a probe tip can be calculated. Finally, the force control of the pneumatic force control system, calculating the distance between the target position and a probe tip, the control processes are integrated with designed the control interface. Visual C++ code from MFC is used to finish the control interface. From experimental results, the position error can be controlled within ± 1 pixel.

scholarly journals Pneumatic cylinders: modelling and feedback force-control

2006 ◽  
Vol 79 (6) ◽  
pp. 650-661 ◽  
Author(s):  
A. Ilchmann ◽  
O. Sawodny ◽  
S. Trenn
Keyword(s):  
Force Control ◽  
Pneumatic Cylinders

Multiobjective Optimum Design of a Symmetric Parallel Schönflies-Motion Generator

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
O. Altuzarra ◽  
A. Hernandez ◽  
O. Salgado ◽  
J. Angeles
Keyword(s):  
Optimum Design ◽  
Closed Form Expression ◽  
Design Parameters ◽  
Pareto Optimum ◽  
Motion Generation ◽  
Form Expression ◽  
The Subject ◽  
Schönflies Motion ◽  
Objective Being ◽  
Motion Generator

The multiobjective optimization of a four-degree-of-freedom symmetric parallel manipulator for Schönflies-motion generation is the subject of this paper. First, the inverse positioning problem is discussed, along with its velocity analysis. The workspace is then analyzed, thereby deriving a closed-form expression of the workspace volume, which depends on the orientation of the moving platform. Next, the isotropic design of the manipulator is obtained. Then, the dexterity analysis of the manipulator is conducted, which is one objective of the optimum design of the manipulator, a second objective being a normalized workspace volume. Finally, the results of the optimization process are reported in terms of a set of Pareto-optimum pairs of the design parameters.

Multiplexed Force Control of Pneumatic Muscles

2006 ◽  
Author(s):  
V. Jouppila ◽  
A. Ellman
Keyword(s):  
High Power ◽  
Force Control ◽  
Weight Ratio ◽  
Pressure Control ◽  
Pneumatic Actuators ◽  
Pneumatic Muscle ◽  
Servo Valve ◽  
Highly Nonlinear ◽  
Muscle Actuators ◽  
Pneumatic Cylinders

Pneumatic actuators are often used in applications that require high power-to-weight ratio, combined with low price and clean and fast operation. However, due to the compressibility of air and highly nonlinear behavior of seal friction, the position and force control of these actuators is difficult to manage. As a result, pneumatic cylinders have been used for many years solely in simple repetitive tasks requiring only a very limited amount of system control. Nonetheless, the pneumatic actuators have properties such as compactness, high power-to-weight ratio, and simplicity that are desirable features in advanced robotics. To overcome the shortcomings, a number of advanced pneumatic components have been developed, of which the most promising is the pneumatic muscle. Compared to a cylinder, a pneumatic muscle not only has a higher power-to-weight and power-to-volume ratio but it is also almost frictionless and has zero leakage. In spite of the muscle actuator's nonlinear force-to-contraction characteristics, many motion and force control methods have been successfully applied to it. The characteristics of the actuator enable it to be used in simple positioning systems and as a variable gas spring. The actuator's almost linear pressure-to-force ratio is extremely well-suited to a variety of gripping and pressing applications. Due to the muscle actuator's characteristics and recent developments in pneumatic valve technology, there is an opportunity to share a single pressure control servo valve among multiple muscle actuators. The multiplexed control of the actuators with only one servo valve reduces the system costs significantly. In this paper we investigate the feasibility of employing multiplexed force control of four pneumatic muscle actuators. In the system, pressure is controlled by a single proportional pressure valve. High-speed switching valves are used for activating the pressure control for each muscle actuator in the desired manner. Pneumatic cylinders are attached to the other ends of the muscles in order to cause controllable position disturbances. The displacement, force and pressure of each muscle are measured with appropriate sensors. The system behavior is investigated under position disturbances.

scholarly journals ONE MODEL OF A POINT-RATING SYSTEM FOR EVALUATING THE KNOWLEDGE OF UNIVERSITY BACHELORS IN THE DISCIPLINE «MATHEMATICS»

2021 ◽  
Vol 23 (79(2)) ◽  
pp. 187-193
Author(s):  
Yu.V. Gumennikova ◽  
◽  
L.V. Kaidalova
Keyword(s):  
Educational Process ◽  
Assessment System ◽  
Rating System ◽  
Simplified Model ◽  
Practical Application ◽  
Final Assessment ◽  
Cumulative System ◽  
The Subject ◽  
Independent Work

The article describes the simplified model of the point-rating assessment system developed by the author, which he called the cumulative system of points in mathematics when teaching bachelors of the specialty 38.03.01-Economics, and analyzes the results of its practical application. It differs from most existing BRS models in that the points received by the student for work during the semester are not a mandatory component of the final assessment, but act as an addition to the assessment received at the intermediate certification. The proposed cumulative system of points for the discipline "Mathematics" does not require much effort from the teacher and is simple and understandable for students, while the final assessment becomes more objective. The use of a cumulative system of points leads to the activation of independent work of students during the entire period of studying mathematics, the growth of interest in the subject, which contributes to improving the quality of the educational process.

A discussion on advanced methods of energy conversion- Magnetohydrodynamic power generation - The science of m.h.d. generators- a critical survey

1967 ◽  
Vol 261 (1123) ◽  
pp. 347-359 ◽  
Keyword(s):  
Superconducting Magnet ◽  
Critical Survey ◽  
Fuel Type ◽  
General Introduction ◽  
Generator System ◽  
Turbine Plant ◽  
Scientific Papers ◽  
Steam Turbine Plant ◽  
The Subject ◽  
The Stability

This paper is intended to provide a general introduction to the subject and provide a background for the detailed scientific papers appearing later in the meeting. The various types of m.h.d. generator are briefly discussed and the basic theory of m.h.d.generation is described. The open cycle fossil fuel type of m.h.d. generator system in which the exhaust gases from the m.h.d. duct are used to power a steam turbo alternator generator is discussed in more detail and the major problem areas identified. These include the stability of the flow in the m.h.d. duct, the provision of long lived electrodes, air preheaters, seed recovery apparatus and the development of a suitable superconducting magnet. The influence of the parameters of the various components on the performance of the complete m.h.d./steam turbine plant is discussed.

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