Command Shaping Under Nonsymmetrical Acceleration and Braking Dynamics

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Thomas H. Bradley ◽  
Jon Danielson ◽  
Jason Lawrence ◽  
William Singhose
Keyword(s):  
Nonlinear System ◽  
Numerical Optimization ◽  
Analytic Solution ◽  
Effective Means ◽  
Optimization Approach ◽  
Bridge Crane ◽  
Residual Vibration ◽  
Command Shaping ◽  
Shaping Technique ◽  
Braking Dynamics

The conventional unity magnitude zero vibration (UM-ZV) command shaping technique is an effective means for eliminating vibration in linear mechanical systems with on-off actuators. This paper discusses how the UM-ZV command shaping technique is affected by a common nonlinearity: nonsymmetrical accelerating and braking dynamics. Two approaches for creating new types of UM-ZV shaped commands are presented: a closed-form analytic solution and a numerical optimization approach. Both methods reduce residual vibration of the nonlinear system more effectively than the conventional UM-ZV shaped commands. Simulations and experiments on a bridge crane confirm the effectiveness of the new commands.

A numerical optimization approach to acoustic hull array design

2002 ◽  
Vol 112 (6) ◽  
pp. 2735-2741 ◽  
Author(s):  
Thomas A. Wettergren ◽  
John P. Casey ◽  
Roy L. Streit
Keyword(s):  
Numerical Optimization ◽  
Optimization Approach ◽  
Array Design

Optimal Performance of the TLCD in Structural Pitching Vibration Control

2002 ◽  
Vol 8 (5) ◽  
pp. 619-642 ◽  
Author(s):  
S. D. Xue ◽  
J. M. Ko ◽  
Y. L. Xu
Keyword(s):  
Numerical Optimization ◽  
Sensitivity Study ◽  
Optimization Approach ◽  
Optimum Control ◽  
Head Loss Coefficient ◽  
Tuning Ratio ◽  
Mass Moment ◽  
Practical Design ◽  
Mass Moment Of Inertia ◽  
Structural Uncertainties

A detailed optimal parametric study is performed for a tuned liquid column damper (TLCD) in suppressing the pitching vibration of structures. Due to the difficulty of finding analytical solutions for the damped structure, a numerical optimization approach is proposed and applied to the system to find the optimum TLCD parameters. The variations of the optimum control parameter with system parameters are determined and discussed. Using various numerical searching data, a set of practical design formulas for the optimum tuning ratio and optimum head loss coefficient of the TLCD are then derived through regression analysis. The comparison between practical design formula and numerical optimization shows a very close agreement between the two results. The practical design formulas provide a convenient tool for designers. In order to account for the possible effects of structural uncertainties, a parametric sensitivity study on the de-tuning of optimum damper parameters is also carried out. It is found that the detuning effect is more severe for low damped structure with lower ratios of mass moment of inertia, especially for the detuning of tuning ratio.

The Use of Stress Reduces in suddenly Changed Section of Rounded Shafts

2011 ◽  
Vol 147 ◽  
pp. 9-13
Author(s):  
S.R. Mohebpour ◽  
Mohammad Vaghefi
Keyword(s):  
Stress Concentration ◽  
Numerical Optimization ◽  
Optimization Approach ◽  
Geometrical Shape ◽  
New Concepts ◽  
Concentration Factors ◽  
Geometrical Change ◽  
Stress Concentration Factors ◽  
Reducing Stress ◽  
Dangerous Section

Reducing stress concentration is mainly done by fillets. However, new concepts toward better material properties lead designers and engineers to use these materials in their design, still changing in geometrical shape of desired models can help us in reducing stress concentration factors. New devices, including fast computers, reliable numerical methods (FEM), and numerical optimization approach can bring special devices for better designing besides considering design limitations in special industries. In this paper we focus on geometrical change (rounded groove) in the sudden changed section of the rounded shaft to reduce stress concentration in the most dangerous section. By optimizing this proposed change in the geometry of shaft we reduce the stress, so using of fillets can be neglected in the future designs to prevent metallurgical and design limitations.

Friction-Compensating Command Shaping for Vibration Reduction

2004 ◽  
Vol 127 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Jason Lawrence ◽  
William Singhose ◽  
Keith Hekman
Keyword(s):  
Steady State ◽  
Coulomb Friction ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Residual Vibration ◽  
Command Shaping ◽  
Point Motion ◽  
Common Operation ◽  
Point To Point ◽  
Theoretical Developments

Fast and accurate point-to-point motion is a common operation for industrial machines, but vibration will frequently corrupt such motion. This paper develops commands that can move machines without vibration, even in the presence of Coulomb friction. Previous studies have shown that input shaping can be used on linear systems to produce point-to-point motion with no residual vibration. This paper extends command-shaping theory to nonlinear systems, specifically systems with Coulomb friction. This idea is applied to a PD-controlled mass with Coulomb friction to ground. The theoretical developments are experimentally verified on a solder cell machine. The results show that the new commands allow the proportional gain to be increased, resulting in reduced rise time, settling time, and steady-state error.

Parameter Inversion of Thin-Walled Structure Using Numerical Optimization Approach

2011 ◽  
Vol 308-310 ◽  
pp. 1614-1618
Author(s):  
Zhuo Meng ◽  
Qin Sun ◽  
Jin Feng Jiang
Keyword(s):  
Numerical Optimization ◽  
Impact Load ◽  
Optimization Approach ◽  
Optimization Software ◽  
Material Parameters ◽  
Finite Element Software ◽  
Whole Process ◽  
Parameter Inversion ◽  
Thin Walled ◽  
Walled Cylinder

Based on the theory of structure impact dynamic and numerical optimization, application of SQP algorithm in nonlinear parameter inversion is demonstrated in this paper by combining the optimization software and finite element software. Parameter inversion of thin-walled cylinder subjected to axial impact load is studied. The material parameters of thin-walled cylinder are obtained from inversion; besides, the whole process of numerical optimization parameter inversed method is demonstrated.

Approximation Performance of BP Neural Networks Improved by Heuristic Approach

2013 ◽  
Vol 411-414 ◽  
pp. 1952-1955 ◽  
Author(s):  
Shuo Ding ◽  
Xiao Heng Chang ◽  
Qing Hui Wu
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Bp Neural Network ◽  
Numerical Optimization ◽  
Heuristic Algorithms ◽  
Nonlinear Function ◽  
Heuristic Approach ◽  
Optimization Approach ◽  
Bp Neural Networks ◽  
The One

Among all improved BP neural network algorithms, the one improved by heuristic approach is studied in this paper. Firstly, three types of improved heuristic algorithms of BP neural network are programmed in the environment of MATLAB7.0. Then network training and simulation test are conducted taking a nonlinear function as an example. The approximation performances of BP neural networks improved by different numerical optimization approaches are compared to aid the selection of proper numerical optimization approach.

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