Design of Nonlinear Rotational Stiffness Using a Noncircular Pulley-Spring Mechanism

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Bongsu Kim ◽  
Ashish D. Deshpande
Keyword(s):  
Inverted Pendulum ◽  
Synthesis Method ◽  
Gravity Compensation ◽  
Passive Torque ◽  
Double Exponential ◽  
Torque Generation ◽  
Synthesis Procedure ◽  
Decomposition Experiments ◽  
Spring Mechanism ◽  
The Masses

We present a new methodology for designing a nonlinear rotational spring with a desired passive torque profile by using a noncircular pulley-spring mechanism. A synthesis procedure for the shape of the noncircular pulley is presented. The method is based on an infinitesimal calculus approach that leads to an analytical solution, and the method is extended to address practical design issues related to the cable routing. Based on the synthesis method, an antagonistic spring configuration is designed for bilateral torque generation and is designed such that there is no slack in the routing cables. Two design examples are presented, namely, double exponential torque generation and gravity compensation for an inverted pendulum. Experiments with a mechanism for gravity compensation of an inverted pendulum validate our approach. We extend our approach to generate nonlinear torques at two joints by introducing the concept of torque decomposition. Experiments with a two-link robotic arm show that the gravitational forces from the masses on each link are accurately compensated for with our noncircular pulley-spring mechanisms.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

A Negative Impedance Approach to the Design Synthesis and Control of Multi-Energy Active Elements

2005 ◽  
Author(s):  
Thomas J. Connolly
Keyword(s):  
Control System ◽  
Synthesis Method ◽  
Design Tool ◽  
Electric Motors ◽  
Active Device ◽  
Design Synthesis ◽  
System Architectures ◽  
Active Devices ◽  
Synthesis Procedure ◽  
And Control

This paper covers the continuing development and experimental validation of our approach to the design synthesis and control of active devices in dynamic mechanical systems. Active devices, such as electric motors and hydraulic actuators, require an external power input. An innovative feature of this synthesis approach is the use of non-physically realizable elements, i.e., elements that have negative impedances, to model the behavior of an active device. The synthesis method also features the use of bond graphs, as they facilitate modeling of multi-energy systems and devices. The procedure applies to the design or retrofit of systems for which a desired frequency response is prescribed. The overarching goal of the synthesis method is to yield options for the general framework of a controllable, stable, and parameterizable system, using simulation-based techniques. Thus the procedure yields a stable “first draft” of the active device and its control system that can be handed off to respective specialists for further refinement. Simulation results indicate that design possibilities can include purely active devices or a hybrid combination of active and passive elements. In addition, atypical control system architectures, that depart from traditional PI, PD, or PID controllers can arise from the synthesis procedure. We describe validation experiments that use electric motors and rack-and-pinion systems to achieve active control of a quarter-vehicle test article. The results will provide insight into: (1) refining the synthesis procedure to include systems that feature continuous elements, (2) partially automating the synthesis procedure to make it a more versatile design tool, and (3) practical limitations of the synthesis method.

scholarly journals PEGylated Gold Nanoparticles with Interesting Plasmonic Properties Synthesized Using an Original, Rapid, and Easy-to-Implement Procedure

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Ștefan Nițică ◽  
Alin Iulian Moldovan ◽  
Valentin Toma ◽  
Cristian Silviu Moldovan ◽  
Ioana Berindan-Neagoe ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Synthesis Method ◽  
Average Diameter ◽  
Liquid Droplets ◽  
Sers Substrates ◽  
New Class ◽  
One Step ◽  
Short Synthesis ◽  
Spherical Gold Nanoparticles ◽  
Synthesis Procedure

In this letter, we report a new, one-step, rapid, and easy-to-implement method for the synthesis of PEGylated gold nanoparticles (PEG-AuNPs) having a narrow size distribution and very interesting plasmonic properties. Unmodified polyethylene glycol molecules with a molecular weight of 1000 g/mole (PEG1000) have been employed as reducing and capping agents for the synthesis of spherical gold nanoparticles having an average diameter of 35 nm, within a few minutes. The novelty of the herein proposed synthesis method consists in the fact that the synthesis takes place inside of a sealed bottle flask containing aqueous solutions of PEG1000, tetrachloroauric(III) acid (HAuCl4), and NaOH, placed in the center of a microwave oven, capable to provide a very uniform temperature environment. It turned out that, during the very short synthesis procedure (2 minutes), PEG 1000 suffers an oxidative transformation in such a manner that its terminal alcohol groups (-CH2-OH) are transformed in carboxylate ones (-COO−). The as-synthesized PEG-AuNPs possess very interesting plasmonic properties allowing the detection of different molecules by means of SER spectroscopy performed either in liquid droplets or on solid spots. As a consequence of their unique plasmonic properties, the SER spectra acquired using this new class of nanoparticles on different molecules of interest (methylene blue, rhodamine 6G, doxorubicin, and 5-fluorouracil) are highly reproducible, making them ideal candidates for further use as SERS substrates.

scholarly journals Performance of Rotary Inverted Pendulum by Different Tuning Methods in PID Controller

2020 ◽  
Vol 8 (6) ◽  
pp. 2794-2797
Keyword(s):  
Inverted Pendulum ◽  
Intelligent System ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Pole Placement ◽  
Modern World ◽  
Control Analysis ◽  
Tuning Method ◽  
Internal Model Controller ◽  
Tuning Methods

Now a day’s is over intelligent system is well developed to produce a complicated technique for sensible management systems .Modern world the technology is developing faster .The system has to different control techniques and various theories are updated faster. Now here control analysis of various pendulums especially cart pendulum, rotary(furuta) inverted pendulum in various techniques like Proportional Integral and Derivative controller using some different tuning techniques like Ziegler Nichols method, Direct synthesis method, pole placement method, Cohen Coon method, Internal Model Controller method. They are several tuning method are available, but we are chose to three method. The analysis of various problems from various sources and simulated it in MAT LAB. We are measure the raise time, settling time and peak over shoot. In simulation result is compare to the theoretical calculation.

Towards the Design of Compliant Continuum Topologies With Geometric Nonlinearity

1999 ◽  
Author(s):  
A. Saxena ◽  
G. K. Ananthasuresh
Keyword(s):  
Finite Element ◽  
Linear Models ◽  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Finite Element Models ◽  
Computationally Efficient ◽  
Mechanics Model ◽  
Nonlinear Design ◽  
Nonlinear Force ◽  
Synthesis Procedure

Abstract Optimal design methods that use continuum mechanics model for the deformation of the elastic body, are capable of generating suitable topology, shape, and dimensions of compliant mechanisms for desired specifications. Elastic analysis with linear finite element models employed in the synthesis procedures to date is not quantitatively accurate for large displacement situations. Also, the design specifications involving nonlinear force-deflection characteristics and generation of a curved path for the output port are difficult to realize with linear models. In this paper, the synthesis of compliant mechanisms is performed using geometrically nonlinear finite element models that appropriately account for large displacements. Frame elements are chosen for developing the synthesis procedure because of ease of implementation of the general approach and their ability to capture bending deformations. A computationally efficient method for computing the nonlinear design sensitivities is described. Examples are included to illustrate the usefulness of the synthesis method.

Kinematic Geometry Description of a Line With Four Positions and Its Application in Dimension Synthesis of Spatial Linkage

2020 ◽  
Vol 12 (3) ◽  
Author(s):  
Song Lin ◽  
Hanchao Wang ◽  
Yu Zhang ◽  
Jingyu Jiang
Keyword(s):  
Synthesis Method ◽  
Projection System ◽  
Geometric Characteristics ◽  
Geometric Problems ◽  
Kinematic Geometry ◽  
Plane Projection ◽  
Synthesis Procedure ◽  
Spatial Linkages ◽  
Geometric Relationship ◽  
Geometric Elements

Abstract In the dimension synthesis of the spatial linkages, the geometric characteristics of floating links in mechanisms reveal the geometric relationship between the motion task and the dimensions of the mechanisms. In order to establish the kinematic geometry rules corresponding to the motion of the floating link, this paper transforms the kinematic problems of geometric elements on the floating link into geometric problems and uses the geometric procedure to solve the spatial linkages synthesis problem with four given positions. In a previous work, we have extracted the kinematic geometry rules of a line with two and three positions. However, as the number of task positions increases, the kinematic characteristics representing the position transformation become more complicated. The method proposed in this paper extends the previous work to four given positions and builds up the geometric relationships among the kinematic rules for two, three, and four positions. The establishment of this geometric relationship is helpful to unify the synthesis procedure of synthesis problems with different number of positions. After that, the two-plane projection system and the transformation of projection are introduced to establish a procedural graphical synthesis method.

Shape and Size Synthesis of Compliant Mechanisms Using Wide Curve Theory

2005 ◽  
Vol 128 (3) ◽  
pp. 551-558 ◽  
Author(s):  
Hong Zhou ◽  
Kwun-Lon Ting
Keyword(s):  
Cross Section ◽  
Optimization Problem ◽  
Compliant Mechanisms ◽  
Synthesis Method ◽  
Free Form ◽  
Control Parameters ◽  
Synthesis Procedure ◽  
Curve Theory ◽  
Practical Constraints ◽  
Shape And Size

A wide curve is a curve with width or cross section. This paper introduces a shape and size synthesis method for compliant mechanisms based on free-form wide curve theory. With the proposed method, detailed dimensions synthesis can be performed to further improve the performance after the topology is selected. Every connection in the topology is represented by a parametric wide curve in which variable shape and size are fully described and conveniently controlled by the limited number of parameters. The shape and size synthesis is formulated as the optimization of the control parameters of wide curves corresponding to all connections in the topology. Problem-dependent objectives are optimized and practical constraints are imposed during the optimization process. The optimization problem is solved by the constrained nonlinear programing algorithm in the MATLAB Optimization Toolbox. Two examples are included to demonstrate the effectiveness of the proposed synthesis procedure.

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