Robust Input Shaper Control Design for Parameter Variations in Flexible Structures

1999 ◽  
Vol 122 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Lucy Y. Pao ◽  
Mark A. Lau
Keyword(s):  
Design Method ◽  
Structural Parameters ◽  
Flexible Structures ◽  
Control Design ◽  
Input Shaping ◽  
Input Shaper ◽  
Modeling Errors ◽  
Parameter Variations ◽  
Damped Systems ◽  
Parameter Values

Input shaping has been shown to yield good performance in the control of flexible structures while being insensitive to modeling errors. However, previous studies do not take into account the distributions of the parameter variations. We develop a new input shaping method that allows the ranges of system parameter values to be weighted according to the expected modeling errors. Comparisons with previously proposed input shaper designs are presented to illustrate the qualities of the new input shaper design method. These new shapers will be shown to have better robustness under uncertainty in structural parameters and shorter shaper lengths for lightly damped systems. [S0022-0434(00)02201-2]

Control Design for the Active Stabilization of Rail Wheelsets

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
T. X. Mei ◽  
H. Li
Keyword(s):  
Design Method ◽  
Control Design ◽  
Optimization Procedure ◽  
Control Analysis ◽  
Design And Optimization ◽  
Stabilization Control ◽  
Number Of Factors ◽  
Parameter Variations ◽  
Active Stabilization

Through a detailed control assessment of a conventional railway wheelset, this paper addresses some of the key design issues in the development of active primary suspensions for the stabilization control of railway vehicles. It reveals the basic feedback requirements for achieving adequate stability and hence provides a useful insight of how active controllers may be structured. For the control design, a number of factors in addition to the stabilization are considered including the actuation requirements, creep forces at the wheel-rail contact, track following as well as robustness against parameter variations. Based on the outcome of the control analysis, the study proposes a design and optimization procedure for the development of active wheelset control. The design method is applied to a two-axle vehicle in a case study, which shows that the new design approach is advantageous when compared with other design methods previously studied.

Robust Negative Input Shapers for Vibration Suppression

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Joshua Vaughan ◽  
Aika Yano ◽  
William Singhose
Keyword(s):  
Rise Time ◽  
Vibration Suppression ◽  
Control Method ◽  
High Mode ◽  
Input Shaping ◽  
Bridge Crane ◽  
Modeling Errors ◽  
Parameter Variations ◽  
Mode Excitation ◽  
Theoretical Predictions

Input shaping is a control method that limits motion-induced oscillation in vibratory systems by intelligently shaping the reference command. As with any control method, the robustness of input shaping to parameter variations and modeling errors is an important consideration. For input shaping, there exists a fundamental compromise between robustness to such errors and system rise time. For all types of shapers, greater robustness requires a longer duration shaper, which degrades rise time. However, if a shaper is allowed to contain negative impulses, then the shaper duration may be shortened with only a small cost of robustness and possible high-mode excitation. This paper presents a thorough analysis of the compromise between shaper duration, robustness, and possible high-mode excitation for several negative input-shaping methods. In addition, a formulation for specified negative amplitude, specified insensitivity shapers is presented. These shapers provide a continuous spectrum of solutions for the duration/robustness/high-mode excitation trade-off. Experimental results from a portable bridge crane verify the theoretical predictions.

Vibration Reduction Using Multi-Hump Input Shapers

1997 ◽  
Vol 119 (2) ◽  
pp. 320-326 ◽  
Author(s):  
W. E. Singhose ◽  
L. J. Porter ◽  
T. D. Tuttle ◽  
N. C. Singer
Keyword(s):  
Parameter Uncertainty ◽  
Control Experiment ◽  
Space Shuttle ◽  
Vibration Reduction ◽  
Input Shaping ◽  
Input Shaper ◽  
Shaping Process ◽  
Modeling Errors ◽  
System Input ◽  
Computer Controlled

Input shaping is a method for reducing residual vibrations in computer-controlled machines. Vibration is eliminated by convolving an input shaper, which is a sequence of impulses, with a desired system command to produce a shaped input. The shaped input then becomes the command to the system. Requiring the vibration reduction to be robust to modeling errors and system nonlinearities is critical to the success of the shaping process on any real system, Input shapers can be made very insensitive to parameter uncertainty; however, increasing robustness usually increases system delays. A design process is presented that generates input shapers with insensitivity-to-time-delay ratios that are much larger than traditionally designed input shapers. The advantages of the new shapers are demonstrated with computer simulations and their performance is verified with experimental results from the MIT Middeck Active Control Experiment, which was performed on board the Space Shuttle Endeavor.

Sliding Mode Control for Flexible Structures With μ Control-Based Frequency-Shaping Hyperplane

1995 ◽  
Author(s):  
Kenzo Nonami ◽  
Hidekazu Nishimura
Keyword(s):  
Sliding Mode Control ◽  
Control Method ◽  
Reference Model ◽  
Sliding Mode ◽  
Design Method ◽  
Flexible Structures ◽  
Frequency Region ◽  
High Rise ◽  
Mode Control ◽  
Parameter Variations

Abstract This paper proposes a new sliding mode control method using μ synthesis theory. This concept is based on the frequency-shaped approach. A conventional hyperplane consisits of a desired reference model without dynamics. Therefore, the sliding mode control system becomes often unstable based on spillover phenomena in a higher frequency region. On the other hand, the proposed design method can completely suppress such spillover phenomena because of the frequency-shaped hyperplane. Also, it has good robustness and robust performance in cases of parameter variations on the hyperplane to minimize the maximum singular value and structured sigular value from some noise to the controlled variables. We have just applied this new method to the flexible structure of the miniature test rig with four stories like high rise building. We have verified from simulations and experiments that the new sliding mode control method proposed in this paper has good performances and it is very useful to suppress the spillover in a higher frequency region.

Adaptive Input Shaping for Nonlinear Systems: A Case Study

2006 ◽  
Vol 129 (2) ◽  
pp. 219-223 ◽  
Author(s):  
John Stergiopoulos ◽  
Anthony Tzes
Keyword(s):  
System Theory ◽  
Nonlinear Systems ◽  
Input Shaping ◽  
Relative Time ◽  
Pendulum System ◽  
Input Shaper ◽  
Command Input ◽  
Damped Systems ◽  
Theoretical Results

Input shaping is a technique that seeks to reduce residual vibrations of lightly damped systems through modification of the command input to the system. Although several input shaping techniques have been derived primarily from linear system theory, theoretical results are hard to be traced for their application to nonlinear systems. In most of the reported cases, a fixed shaper is designed based on the linearized version around an operating point of the nonlinear system. In this paper, an adaptive form of the input shaper is proposed for a class of nonlinear lightly damped systems. The adaptive shaper adjusts the magnitude and relative time difference between its impulses according to the instant frequency and damping of the linearized systems. The efficacy of the proposed scheme and its comparison to a fixed shaper is investigated through its application to a pendulum system. The adaptive shaper’s parameters vary according to the pendulum’s angle. The illustrative examples indicate the deficiencies of the fixed case and demonstrate the efficacy of the designed controller.

Multivariate design and analysis of aircraft HEX under multiple working conditions within flight envelope

2021 ◽  
pp. 1-18
Author(s):  
Qihang Liu ◽  
G.Q. Xu ◽  
Jie Wen ◽  
Yanchen Fu ◽  
Laihe Zhuang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Design Method ◽  
Structural Parameters ◽  
Optimal Structure ◽  
Clear Correlation ◽  
Pressure Drops ◽  
Design Variables ◽  
Wide Range ◽  
Common Weight

Abstract This paper presents a multi-condition design method for the aircraft heat exchanger (HEX), marking with light weight, compactness and wide range of working conditions. The quasi-traversal genetic algorithm (QT-GA) method is introduced to obtain the optimal values of five structural parameters including the height, the tube diameter, the tube pitch, and the tube rows. The QT-GA method solves the deficiency of the conventional GA in the convergence, and gives a clear correlation between design variables and outputs. Pressure drops, heat transfer and the weight of the HEX are combined in a single objective function of GA in the HEX design, thus the optimal structure of the HEX suitable for all the working conditions can be directly obtained. After optimization, the weight of the HEX is reduced to 2.250 kg, more than 20% lower than a common weight of around 3 kg. Based on the optimal structure, the off-design performance of the HEX is further analyzed. Results show that the extreme working conditions for the heat transfer and the pressure drops are not consistent. It proves the advance of the multi-condition design method over traditional single-condition design method. In general, the proposed QT-GA design method is an efficient way to solve the multi-condition problems related to the aircraft HEX or other energy systems.

scholarly journals Stable Model Predictive Control Design: Sequential Approach

2011 ◽  
Vol 62 (2) ◽  
pp. 99-103
Author(s):  
Vojtech Veselý
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Design Method ◽  
Control Design ◽  
Sequential Design ◽  
Stable Model ◽  
Sequential Approach ◽  
Prediction Horizon ◽  
Guaranteed Cost ◽  
One Step

Stable Model Predictive Control Design: Sequential Approach The paper addresses the problem of output feedback stable model predictive control design with guaranteed cost. The proposed design method pursues the idea of sequential design for N prediction horizon using one-step ahead model predictive control design approach. Numerical examples are given to illustrate the effectiveness of the proposed method.

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