A Priori Motion Profile Control and Dynamic Performance of the Multi-Axis Ride Simulator (MARS) Facility

2007 ◽  
Author(s):  
Valeta Carol Chancey ◽  
Bradley A. Bumgardner ◽  
David D. Turner ◽  
Arlene M. Breaux-Sims ◽  
George T. Flowers ◽  
...  
Keyword(s):  
Dynamic Performance ◽  
A Priori ◽  
Experimental Tests ◽  
Performance Limits ◽  
Actuation System ◽  
Testing Facility ◽  
Profile Control ◽  
Vehicle Motion ◽  
And Performance ◽  
Motion Profile

The Multi-Axis Ride Simulator (MARS) facility is a versatile testing facility for the evaluation of vehicle motion effects on personnel and devices. It consists of a 6-DOF Stewart platform driven by a computer-controlled actuation system. An off-line strategy is used to correct the amplifier input and drive the table dynamic response to the desired trajectory. The capabilities and performance limits of the facility are described in detail. The off-line control strategy is also described and its performance evaluated with a series of experimental tests. The results are presented and discussed in detail.

Research on the New Missile Actuation System with Dual Independent Closed-Loop

2014 ◽  
Vol 551 ◽  
pp. 337-343
Author(s):  
Hui Chen ◽  
Yong Ling Fu ◽  
Juan Chen ◽  
He Song Liu
Keyword(s):  
High Performance ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Actuation System ◽  
High Penetration ◽  
Low Energy Consumption ◽  
Penetration Ability ◽  
Important Direction ◽  
And Performance ◽  
Missile System

With the development of the advanced precision-guided missile and anti-missile system, high precision, high penetration ability and Low energy consumption have become an important direction for the missile. A new missile electro-hydraulic actuation system with dual independent closed-loop is put forward with the trend of high performance and energy-saving, and then the operating principle and process are discussed. Finally the accurate mathematical model is established, and the influence of the different basic pressure on the dynamic performance is analyzed. The simulation results show that the new proposed scheme has made great improvements in reducing the zero-control current of the system, but the efficiency and performance of the actuation system should be considered integrated due to the decrease of the dynamic performance, so it is practical for the future development of the missile electro-hydraulic actuation system.

Railroad Spiral Design and Performance

2012 ◽  
Author(s):  
Louis T. Klauder
Keyword(s):  
Dynamic Performance ◽  
Motion Simulation ◽  
Dynamic Disturbance ◽  
Railroad Tracks ◽  
Perfect Performance ◽  
Spiral Geometry ◽  
Dynamic Performances ◽  
Vehicle Motion ◽  
And Performance ◽  
Derivatives Of

This paper reviews forms of spiral geometry that have been used and proposed as transition shapes in railroad tracks and compares them with respect to dynamic performance and spiral length. The dynamic performances that are compared were calculated using the Gensys rail vehicle motion simulation program and a well known model of the Eurofima coach. The results illustrate: 1) the dynamic disturbance caused by the discontinuity of first derivatives of track curvature and twist with the conventional ‘linear’ spiral; 2) the better dynamic performance of other simple forms of spiral including the virtually perfect performance of two of those forms; and 3) the amounts by which lengths of alternative spirals exceed that of the conventional ‘linear’ spiral for the example transition..

Replication of the Superstition and Performance Study by

2014 ◽  
Vol 45 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Robert J. Calin-Jageman ◽  
Tracy L. Caldwell
Keyword(s):  
Task Difficulty ◽  
Statistical Power ◽  
Meta Analysis ◽  
A Priori ◽  
Significant Heterogeneity ◽  
Performance Study ◽  
Improve Performance ◽  
Research Designs ◽  
Series Of Experiments ◽  
And Performance

A recent series of experiments suggests that fostering superstitions can substantially improve performance on a variety of motor and cognitive tasks ( Damisch, Stoberock, & Mussweiler, 2010 ). We conducted two high-powered and precise replications of one of these experiments, examining if telling participants they had a lucky golf ball could improve their performance on a 10-shot golf task relative to controls. We found that the effect of superstition on performance is elusive: Participants told they had a lucky ball performed almost identically to controls. Our failure to replicate the target study was not due to lack of impact, lack of statistical power, differences in task difficulty, nor differences in participant belief in luck. A meta-analysis indicates significant heterogeneity in the effect of superstition on performance. This could be due to an unknown moderator, but no effect was observed among the studies with the strongest research designs (e.g., high power, a priori sampling plan).

Flow Coefficient Evaluation of Poppet Valves Used in Reciprocating Compressors for LDPE

2008 ◽  
Author(s):  
Enzo Giacomelli ◽  
Massimo Schiavone ◽  
Fabio Manfrone ◽  
Andrea Raggi
Keyword(s):  
Pressure Drop ◽  
Time Pressure ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Operating Life ◽  
High Fatigue ◽  
Strongly Connected ◽  
And Performance ◽  
Poppet Valves

Poppet valves have been used for a long time for very high pressure reciprocating compressors, as for example in the case of Low Density Polyethylene. These applications are very critical because the final pressure can reach 350 MPa and the evaluation of the performance of the machines is strongly connected to the proper operation and performance of the valve itself. The arrangement of cylinders requires generally a certain compactness of valve to withstand high fatigue stresses, but at the same time pressure drop and operating life are very important. In recent years the reliability of the machines has been improving over and over and the customers’ needs are very stringent. Therefore the use of poppet valves has been extended to other cases. In general the mentioned applications are heavy duty services and the simulation of the valves require some coefficients to be used in the differential equations, able to describe the movement of plate/disk or poppet and the flow and related pressure drop through the valves. Such coefficients are often determined in an experimental way in order to have a simulation closer to the real operating conditions. For the flow coefficients it is also possible today to use theoretical programs capable of determining the needed values in a quick and economical way. Some investigations have been carried out to determine the values for certain geometries of poppet valves. The results of the theory have been compared with some experimental tests. The good agreement between the various methods indicates the most suitable procedure to be applied in order to have reliable data. The advantage is evident as the time necessary for the theoretical procedure is faster and less expensive. This is of significant importance at the time of the design and also in case of a need to provide timely technical support for the operating behavior of the valves. Particularly for LDPE, the optimization of all the parameters is strongly necessary. The fatigue stresses of cylinder heads and valve bodies have to match in fact with gas passage turbulence and pressure drop, added to the mechanical behavior of the poppet valve components.

Development of a Ring Permeability Test System

2010 ◽  
Vol 136 ◽  
pp. 153-157
Author(s):  
Yu Hong Du ◽  
Xiu Ming Jiang ◽  
Xiu Ren Li
Keyword(s):  
Control System ◽  
Control Method ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Measuring Method ◽  
Test System ◽  
Fluid Theory ◽  
And Control ◽  
Relationship Of ◽  
The Mathematical Model

To solve the problem of detecting the permeability of the textile machinery, a dedicated test system has been developed based on the pressure difference measuring method. The established system has a number of advantages including simple, fast and accurate. The mathematical model of influencing factors for permeability is derived based on fluid theory, and the relationship of these parameters is achieved. Further investigations are directed towards the inherent characteristics of the control system. Based on the established model and measuring features, an information fusion based clustering control system is proposed to implement the measurement. Using this mechanical structure, a PID control system and a cluster control system have been developed. Simulation and experimental tests are carried out to examine the performance of the established system. It is noted that the clustering method has a high dynamic performance and control accuracy. This cluster fusion control method has been successfully utilized in powder metallurgy collar permeability testing.

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