A Preliminary Analysis of Ski Release Binding Dynamic Properties

1976 ◽  
Vol 98 (3) ◽  
pp. 301-308 ◽  
Author(s):  
C. D. Mote ◽  
M. L. Hull

A piecewise, linear, two degree of freedom, ski release binding dynamic system model is presented for an elementary analysis of binding performance. Dynamic performance criteria and techniques for quantitative evaluation of ski release binding properties are discussed. Desirable binding properties along the loading path, where the ski and boot are separating, and desirable binding properties along the return path where the boot is returning to the ski centerline are discussed separately. General characteristics of the loading and return paths have practical application for binding function.

Author(s):  
Qixin Zhu ◽  
Lei Xiong ◽  
Hongli Liu ◽  
Yonghong Zhu ◽  
Guoping Zhang

Background: The conventional method using one-degree-of-freedom (1DOF) controller for Permanent Magnet Synchronous Motor (PMSM) servo system has the trade-off problem between the dynamic performance and the robustness. Methods: In this paper, by using H∞ control theory, a novel robust two-degree-of-freedom (2DOF) controller has been proposed to improve the position control performance of PMSM servo system. Using robust control theory and 2DOF control theory, a H∞ robust position controller has been designed and discussed in detail. Results: The trade-off problem between the dynamic performance and robustness which exists in one-degree-of-freedom (1DOF) control can be dealt with by the application of 2DOF control theory. Then, through H∞ control theory, the design of robust position controller can be translated to H∞ robust standard design problem. Moreover, the control system with robust controller has been proved to be stable. Conclusion: Further simulation results demonstrate that compared with the conventional PID control, the designed control system has better robustness and attenuation to the disturbance of load impact.


2012 ◽  
Vol 226-228 ◽  
pp. 1755-1759
Author(s):  
Hua Zhang ◽  
Fei Li ◽  
Yu Wei Gao

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.


2003 ◽  
Vol 15 (4) ◽  
pp. 391-397 ◽  
Author(s):  
Shigeki Kudomi ◽  
◽  
Hironao Yamada ◽  
Takayoshi Muto ◽  

We previously developed a six-DOF parallel link force display that is actuated by six hydraulic cylinders. The manipulability of the display, however, was insufficient at first, because the dynamic performance of each cylinder was not necessarily the same as that of the others. To overcome this problem, in the present study we have applied disturbance compensation to improve manipulability. To demonstrate a practical application of this force display, we have also constituted a master-slave system in which the display is adopted as the master, and the same type of hydraulic manipulator is adopted as the slave. An operator manipulated the system so that the slave touched a flexible object serving as a load. Our experiments confirmed that the system was controlled with relatively good dynamic performance, and that the operator was able to feel the load force sensitively through the force display.


Author(s):  
D. A. Saravanos ◽  
C. C. Chamis

Abstract A method is developed for the optimal design of composite links based on dynamic performance criteria directly related to structural modal damping and dynamic stiffness. An integrated mechanics theory correlates structural composite damping to the parameters of basic composite material systems, laminate parameters, link shape, and modal deformations. The inclusion of modal properties allows the selective minimization of vibrations associated with specific modes. Ply angles and fiber volumes are tailored to obtain optimal combinations of damping and stiffness. Applications to simple composite links indicate wide margins for trade-offs and illustrate the importance of various design variables to the optimal design.


2006 ◽  
Vol 326-328 ◽  
pp. 1585-1588
Author(s):  
B.J. Shi ◽  
Dong Wei Shu ◽  
J. Luo ◽  
Q.Y. Ng ◽  
J.H.T. Lau

Hard disk drives (HDD) are now the most important means of information storage, and they continue to be made smaller in size, higher in capacity, and lower in cost. The dynamic performance of an HDD has been an increasingly important consideration for its design, as we move forward toward its consumer applications. The dynamic properties of the head arm assembly (HAA) of a micro-drive were investigated using both experimental and numerical techniques. A finite element model for studying the dynamic property of the HAA was created and modified according to the experimental results. Good correlation between the experimental results and those by finite element simulation was achieved.


1997 ◽  
Vol 23 (6) ◽  
pp. 745-757 ◽  
Author(s):  
Diana L. Deadrick ◽  
Nathan Bennett ◽  
Craig J. Russell

The selection literature has long debated the theoretical and practical significance of dynamic criteria. Recent research has begun to explore the nature of individual performance over time. This study contributes to this body of research through a hierarchical linear modeling analysis of dynamic criteria. The purpose of this study was to investigate the role of ability in explaining initial job performance, as well as the rate of improvement-or performance trend-among a sample of 408 sewing machine operators over a 24 week period. The results of a hierarchical linear modeling analysis suggest that ability measures are differentially related to initial performance and performance improvement trend.


Author(s):  
Shiping Yao ◽  
Colin Morgan ◽  
Nigel J. Leighton

Abstract The basic characteristic of a conventional spring is that of a constant rate, that is a linear force-displacement relationship. If, however, a flat, thin leaf spring is end-loaded past its buckling point it will deform into a curve and the resulting force-displacement relationship can be made virtually flat; that is a very low effective rate is seen, once the buckling force is exceeded. A novel form of automotive active suspension system proposed by Leighton & Pullen (1994) relies upon the “buckled spring” element acting through a variable geometry wishbone assembly to provide wheel to body forces that are controllable by a low power actuator but are virtually independent of wheel to body displacement. The dynamic behavior of the spring element is also significant, since resonance effects may affect the vibration isolating properties of the suspension system and may result in unstable modes of motion. This paper presents a rigorous derivation of the static and dynamic characteristic of the spring element and of the effect of design compromises that are essential for practical application. Comparison of the experimental and simulation results shows that the simulation can be used to predict the static and dynamic performance of the spring.


Author(s):  
Etsujiro Imanishi ◽  
Satoshi Yonezawa ◽  
Naoki Sugano ◽  
Eiko Hirooka ◽  
Takahiro Kobayashi

Abstract A characteristic improvement method for dynamic simulation of a stiff mechanical system by adding mass is presented. Hydraulic systems with check valves and control valves on construction machinery exhibit piecewise-linear characteristics for hydraulic flow rate and spool stroke. The proposed improvement method involves no time delay in determining the mass by considering both eigenvalue distortion of the system and time response. This paper shows a practical application to the boom derricking system of a rough terrain crane, and demonstrates that this method is useful for dynamic simulation of hydraulic system including stiff piecewise-linear elements.


Author(s):  
Akira Saito ◽  
Junta Umemoto ◽  
Kohei Noguchi ◽  
Meng-Hsuan Tien ◽  
Kiran D’Souza

Abstract In this paper, an experimental forced response analysis for a two degree of freedom piecewise-linear oscillator is discussed. First, a mathematical model of the piecewise linear oscillator is presented. Second, the experimental setup developed for the forced response study is presented. The experimental setup is capable of investigating a two degree of freedom piecewise linear oscillator model. The piecewise linearity is achieved by attaching mechanical stops between two masses that move along common shafts. Forced response tests have been conducted, and the results are presented. Discussion of characteristics of the oscillators are provided based on frequency response, spectrogram, time histories, phase portraits, and Poincaré sections. Period doubling bifurcation has been observed when the excitation frequency changes from a frequency with multiple contacts between the masses to a frequency with single contact between the masses occurs.


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