Identification and Control of Hysteresis in Rolling Element Guideways

2005 ◽  
Author(s):  
F. Al-Bender ◽  
W. Symens
Keyword(s):  
Effective Control ◽  
Design Parameters ◽  
Systematic Analysis ◽  
Control Structures ◽  
Frictional Characteristic ◽  
Rolling Element ◽  
Harmonic Analysis Method ◽  
Improved Design ◽  
Stiffness And Damping ◽  
And Control

Rate independent hysteresis seems to be the dominant frictional characteristic found in many machine elements in common engineering use, such as plain and rolling element guideways. The study of the non-linear dynamics caused by such elements becomes imperative if we wish to achieve improved design and, in particular, effective control of such machines. This paper reviews systematic analysis, which we have carried out to characterize the dynamics of rolling element guideways. The dependency of hysteresis characteristics on the bearing design parameters is first investigated and the notion of ‘equivalent’ dynamic quantities, namely stiffness and damping, is introduced. Secondly, a frequency domain, harmonic analysis method for mass-“hysteresis spring” systems, via application of the Describing Function method, is developed and discussed. We checked the validity and applicability of this approach by direct numerical simulation as well as by experiment. The results showed that the (amplitude dependent) Frequency Response Maps invariably contain an “anomalous” region where the response is very sensitive to systems parameter variations. This manifests itself in practice in jump-like phenomena, which thus appear to be inherent features of this type of system. Finally, appropriate control structures for systems with this type of hysteresis elements are proposed and discussed.

Improved Surgical Robot Design Using a Novel Compliant Rolling-Contact Joint

2019 ◽  
Author(s):  
Carl A. Nelson ◽  
Cole A. Dempsey ◽  
Ethan R. Brush ◽  
M. Amine Laribi
Keyword(s):  
Human Robot Interaction ◽  
Rolling Contact ◽  
Surgical Robot ◽  
Excessive Force ◽  
Robot Interaction ◽  
Rolling Element ◽  
Spherical Wrist ◽  
Improved Design ◽  
Safety Features ◽  
And Control

Abstract This paper presents an improved design concept for a surgical robot that contributes to improved human-robot interaction and precise positioning of surgical tools. Based on a spherical wrist design, the robot incorporates new human-safe features limiting its ability to apply excessive force and uses a novel adaptation of the compliant rolling-element (CORE) joint suitable for conical rolling surfaces. The proposed safety features aim to provide novel functionality by mechanically disengaging the drive in overload conditions. This approach avoids the necessity of force sensing and control to detect and compensate for unintended device collisions. Further, proof of concept of a novel compliant rolling-element joint is presented as a low-backlash alternative to bevel gear pairs for heightened precision in angular positioning.

Applying Effective Control to the Conduct of UN Forces

2018 ◽  
Vol 15 (1) ◽  
pp. 9-38 ◽  
Author(s):  
Charuka Ekanayake ◽  
Susan Harris Rimmer
Keyword(s):  
United Nations ◽  
International Law ◽  
Command And Control ◽  
Effective Control ◽  
Legal Systems ◽  
Control Structures ◽  
Core Issue ◽  
And Control

Responsibility is a notion that is central to all legal systems. Its operation in international law, however, has been complicated by (inter alia) the complexity of the operative rules, as well as the intricate factual dynamics on which it is called upon to operate. Such complications often create confusion, mistrust and even accountability gaps in important areas. This article deals with one such area: responsibility for the conduct of United Nations (‘UN’) troops. It commences with an analysis of the notion of responsibility in international law before elaborating the factual dynamics underpinning the relevant legal discussion comprised, inter alia, of the troop contribution frameworks, command and control structures, and the execution of UN orders. The article will then proceed to its core issue: how responsibility for acts directly perpetrated by UN forces (in contrast to other forms of responsibility pertaining to, for instance, aiding and assisting or directing the acts of another) should be apportioned.

Environmental technology: Fluidised-bed steam dryers — latest developments and practical experience

2016 ◽  
pp. 86-90
Author(s):  
Gerald Caspers ◽  
Klaus Nammert ◽  
Holger Fersterra ◽  
Hartmut Hafemann
Keyword(s):  
Data Acquisition ◽  
Early Stage ◽  
Practical Experience ◽  
Great Depth ◽  
Fluidised Bed ◽  
Operating Data ◽  
Beet Pulp ◽  
Improved Design ◽  
Distribution Plate ◽  
And Control

Fluidised-bed steam dryers have been in use for industrial-scale drying of pressed beet pulp for more than 20 years. This highly energy-efficient process can be considered to be state of the art in the industry. Scientific laboratory and pilot-plant testing have provided the basis for a detailed description of the principles of fluidisation and drying in superheated water vapour. Advances in production data acquisition, in particular regarding the options for the real-time presentation and evaluation of high-resolution operating data (Industry 4.0), have opened up new potentials for optimisation of the drying process in fluidised-bed steam dryers. By analysing and interpreting sequences of events, or simultaneous events, it is now possible to analyse process behaviour in great depth. This allows malfunctions to be avoided by improved design or, assisted by suitable measuring and control systems, to be detected at an early stage. Failures can then be prevented altogether by initiating automated countermeasures. On the basis of more recent insights gained from the analysis of faults and disruptions using modern operating data acquisition, BMA’s fluidised-bed steam dryer (WVT) has been subjected to fundamental technological and technical improvements, so it now meets today’s demands for efficiency and reliability. Modifications include the product inlet, the distribution plate and several other parts, in addition to the known and patented PPS (Plug Protection System; EP 2457649 B1), and the patented rotary weir (EP 2146167 B1).

scholarly journals Prevalence, awareness, treatment, and control of hypertension in Nigeria in 1995 and 2020: A systematic analysis of current evidence

2021 ◽  
Author(s):  
Davies Adeloye ◽  
Eyitayo O. Owolabi ◽  
Dike B. Ojji ◽  
Asa Auta ◽  
Mary T. Dewan ◽  
...  
Keyword(s):  
Current Evidence ◽  
Systematic Analysis ◽  
And Control

Momentum exchange impact damper design methodology for object-wall-collision problems

2017 ◽  
Vol 24 (14) ◽  
pp. 3206-3218
Author(s):  
Yohei Kushida ◽  
Hiroaki Umehara ◽  
Susumu Hara ◽  
Keisuke Yamada
Keyword(s):  
Optimal Design ◽  
Design Methodology ◽  
Design Parameters ◽  
Momentum Exchange ◽  
Impact Damper ◽  
One Dimensional ◽  
Practical Design ◽  
Wall Collision ◽  
Damper Design ◽  
And Control

Momentum exchange impact dampers (MEIDs) were proposed to control the shock responses of mechanical structures. They were applied to reduce floor shock vibrations and control lunar/planetary exploration spacecraft landings. MEIDs are required to control an object’s velocity and displacement, especially for applications involving spacecraft landing. Previous studies verified numerous MEID performances through various types of simulations and experiments. However, previous studies discussing the optimal design methodology for MEIDs are limited. This study explicitly derived the optimal design parameters of MEIDs, which control the controlled object’s displacement and velocity to zero in one-dimensional motion. In addition, the study derived sub-optimal design parameters to control the controlled object’s velocity within a reasonable approximation to derive a practical design methodology for MEIDs. The derived sub-optimal design methodology could also be applied to MEIDs in two-dimensional motion. Furthermore, simulations conducted in the study verified the performances of MEIDs with optimal/sub-optimal design parameters.

scholarly journals Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Javaid Ahmad ◽  
Shaohong Cheng ◽  
Faouzi Ghrib
Keyword(s):  
Analytical Model ◽  
Design Parameters ◽  
Reference Base ◽  
Cable Network ◽  
Cable Networks ◽  
Modal Behavior ◽  
Stiffness And Damping ◽  
Main Cables ◽  
The Impact ◽  
Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

Survey and control of small mammal populations on two hardwood plantations in southern Ontario

1974 ◽  
Vol 50 (5) ◽  
pp. 181-185 ◽  
Author(s):  
Andrew Radvanyi
Keyword(s):  
Small Mammal ◽  
Late Summer ◽  
Control Measures ◽  
Effective Control ◽  
Southern Ontario ◽  
Live Trapping ◽  
Surrounding Areas ◽  
And Control ◽  
Rodent Populations ◽  
Ingredient Cost

Live trapping and tagging methods were employed to assess small mammal populations within two hardwood plantations in southern Ontario. Excessive girdling damage in past years to young planted trees necessitated an evaluation of rodent populations and development of effective control measures. The application of an anticoagulant rodenticide to oat groats bait broadcast over the study area at an ingredient cost of approximately three dollars per acre virtually wiped out the small mammals. Reinvasion from surrounding areas was, however, fairly rapid, particularly during late summer. Further research on longer term control measures using poisoned bait feeder stations is recommended.

James Bay Spillways and Control Structures

1981 ◽  
Vol 107 (2) ◽  
pp. 183-198
Author(s):  
Klaus R. Ludwig ◽  
Richard T. Olive
Keyword(s):  
James Bay ◽  
Control Structures ◽  
And Control

Design Optimisation Strategies for a Hydraulic Hybrid Wheel Loader

2018 ◽  
Author(s):  
Karl Uebel ◽  
Henrique Raduenz ◽  
Petter Krus ◽  
Victor Juliano de Negri
Keyword(s):  
Energy Management ◽  
Design Parameters ◽  
Linear Component ◽  
Concept Design ◽  
Energy Management Strategy ◽  
Design Optimisation ◽  
Hydraulic Hybrid ◽  
Deterministic Dynamic ◽  
Control Optimisation ◽  
And Control

This paper deals with design optimisation of hydraulic hybrid drivelines during early concept design phases. To set the design parameters of a hybrid driveline such as gear ratios, pump/motor displacements and size of energy storage, the energy management of the hybrid machine needs to be considered as well. This is problematic since a nested design and control optimisation normally requires substantial computer power and is time-consuming. Few previous studies have treated combined design and control optimisation of hydraulic hybrid vehicles using detailed, non-linear component driveline models. Furthermore, previously proposed design optimisation methods for on-road vehicles are not suitable for heavy off-road machines operating in short repetitive cycles with high transient power output. The paper demonstrates and compares different optimisation approaches for design and control optimisation combining deterministic dynamic programming and non-gradient based numerical optimisation. The results show that a simple rule-based energy management strategy can be sufficient to find the optimal hardware design even though non-optimal control laws are used.

The Surface Roughness Effect on the Dynamic Stiffness and Damping Characteristics of the Hydrostatic Thrust Spherical Bearings: Part 5 of 5 — Clearance Type of Bearings

2007 ◽  
Author(s):  
Ahmad W. Yacout
Keyword(s):  
Surface Roughness ◽  
Capillary Tube ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Major Effect ◽  
Design Parameters ◽  
Compressibility Effect ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Fluid Compressibility

This study has theoretically analyzed the surface roughness, centripetal inertia and recess volume fluid compressibility effects on the dynamic behavior of a restrictor compensated hydrostatic thrust spherical clearance type of bearing. The stochastic Reynolds equation, with centripetal inertia effect, and the recess flow continuity equation with recess volume fluid compressibility effect have been derived to take into account the presence of roughness on the bearing surfaces. On the basis of a small perturbations method, the dynamic stiffness and damping coefficients have been evaluated. In addition to the usual bearing design parameters the results for the dynamic stiffness and damping coefficients have been calculated for various frequencies of vibrations or squeeze parameter (frequency parameter) and recess volume fluid compressibility parameter. The study shows that both of the surface roughness and the centripetal inertia have slight effects on the stiffness coefficient and remarkable effects on the damping coefficient while the recess volume fluid compressibility parameter has the major effect on the bearing dynamic characteristics. The cross dynamic stiffness showed the bearing self-aligning property and the ability to oppose whirl movements. The orifice restrictor showed better dynamic performance than that of the capillary tube.

Sign in / Sign up

Export Citation Format

Share Document